Electrophilic C(sp²)−H Borylation of Nonactivated and Deactivated Arenes with Pyramidal Boron Lewis Superacids

Dedication

Dedicated to Prof. Paul Knochel for his 70th birthday.

Keywords

Borylations - Boron Lewis superacids - Borylating reagents - Pyramidal boranes - Boratriptycenes - C–H borylation reactions

Introduction

Over the past decade, remarkable progress has been made in the transition-metal-free electrophilic C–H borylation of arenes and heteroarenes using borenium ions or other electrophilic borylating species.[1] Directed, transition-metal-free, regioselective electrophilic C–H borylations are increasingly used in organic synthesis using various directing groups and template reagents.[2]

Very recent examples of transition-metal-free electrophilic borylation methods of C(sp²)–H and C(sp³)–H bonds have been reported by the groups of Fontaine,[3] Ingleson,[4] Wang,[5] and Houk and Shi,[6] propelling this emerging field in a new, exciting direction.

We previously employed a pyramidal boron Lewis superacid derived from our 9-boratriptycene platform[7] as a strongly electrophilic borylation reagent able to achieve some C(sp²)–H borylations.[8] This boron Lewis superacid generated in situ in solution, in combination with a proper weakly coordinating counteranion (WCA = B(C₆F₅)₄ ⁻, Tf₂N⁻, Tf₃C⁻) and a suitable Brønsted base, enabled the electrophilic C–H borylation of substituted aromatics with moderate to good yields.

However, the aromatic substrates had to be used in very large excess (as solvents), which precluded the use of solid arenes or of structurally complex molecules ([Scheme 1]). The mechanism of these C–H borylations has not been investigated so far.

Scheme 1 Previous examples of electrophilic C−H borylations of arenes reported by us,[8] via the in situ generation of the 10-sulfonium-9-boratriptycene pyramidal boron Lewis superacid in the aromatic solvent. TMA = N,N,3,5-tetramethylaniline.

We now report a regioselective electrophilic C(sp²)–H borylation methodology for a wide range of functionalized aromatics and polyaromatics, together with a mechanistic investigation of these electrophilic C–H borylation reactions. The aromatic substrates can now be used in relatively low excess (e.g., 30 equiv) and no longer need to be used as the solvent (i.e., 244 equiv on average).

Reaction Optimization

We started our investigation by screening for an unreactive solvent, using benzene as the substrate. We observed that common solvents such as 1,2-dichloro- and 1,2-difluorobenzene reacted under the reaction conditions, producing inseparable mixtures of the target product and solvent-borylation byproducts, indicating that even electron-poor halogenated aromatics undergo borylation ([Table 1] entries 1 and 2).

Table 1 Solvents screening for the optimization of the electrophilic C(sp²)–H borylation of benzene

Entry	Solventa	Yield (%)b
1	1,2-Dichlorobenzene	/c
2	1,2-Difluorobenzene	/c
3	1-Bromo-3,4,5-trifluorobenzene	~5
4	1-Bromo-2,4,6-trifluorobenzene	42
5	1,2,3,4-Tetrafluorobenzene	48
6	1,3,5-Trifluorobenzene	47
7	p-Xylene	~5
8	Mesitylene	~5

^aUse of apolar aromatic hydrocarbons led to poor yields, which was attributed to the very low solubility of the reagents.

^b1H NMR yields using 4-bromoanisole as the internal reference.

^cObtained as an inseparable mixture of phenyl- and 3,4-dihalophenyl-boronate complexes.

1,2,3,4-Tetrafluorobenzene emerged as the optimal solvent, although identical results were obtained with the more cost-effective 1,3,5-trifluorobenzene ([Table 1], entries 5 and 6), despite its apparently lower reagent solubility.

Nonhalogenated arene solvents led to low yields ([Table 1], entries 7 and 8), mostly due to the insolubility of the starting material and HNTf₂, leading to incomplete protodeborylation.

With suitable solvents identified, we next optimized the stoichiometry of the aromatic substrates. The goal was to maximize yields while maintaining low substrate excess ([Table 2]). Increasing the number of equivalents of benzene from 10 to 30 increased the yield to 85% ([Table 2], entry 3). Further increasing the amount of benzene further to 40 or 50 equiv had only a modest effect on the reaction yield ([Table 2], entries 4 and 5); therefore, 30 equiv were selected for further optimization.

Table 2 Optimization of benzene and chlorobenzene equivalents

Entry	Substrate equivalents	Concentration (mol L−1)	Yield (%)a
	Benzene
1	10	0.49	48a
2	20	0.94	66a
3	30	1.35	85a
4	40	1.73	86a
5	50	2.08	89a
	Chlorobenzene
6	30	1.33	29b
7	40	1.70	35b
8	50	2.04	58b
9	60	2.35	61b
10	80	2.90	66b

^aNMR yields using 4-bromoanisole as internal reference.

^bIsolated yield.

Using chlorobenzene as a benchmark for deactivated arenes resulted in drastically decreased yield of 29% with 30 equiv of arene ([Table 2], entry 6). However, a satisfactory yield of 66% was reached with 80 equiv of chlorobenzene ([Table 2], entry 10), which was adopted as the optimal conditions for the borylation of deactivated arenes.

Substrate Scope Investigation

With suitable experimental conditions in hand for the C(sp²)–H borylation of aromatics, and after an extensive screening of 16 Brønsted bases (see Table S1 in the Supporting Information), the substrate scope was examined with a particular focus on unactivated and deactivated arenes, which are challenging substrates for electrophilic aromatic substitution reactions in general. The amount of base was increased from 3 to 6 equiv to ensure high yields across structurally diverse arenes. With our new conditions being compatible with solid substrates (highlighted in light gray in [Scheme 2]), we first evaluated arenes with an extended π-system. Similarly to the parent phenylboronate 2a, naphthyl 2b and anthracenyl borate 2c were obtained in 82% and 85% yield, respectively, with full selectivity for the less-hindered position.

Interestingly, the use of dibenzothiophene 1d results in nonequivalent meta and para positions that were borylated in the same ratio, affording 48% total yield using only 15 equiv of arene.

We found that biphenyls 1e–g displayed good reactivity and regioselectivity. First, biphenyl 1e afforded the desired product 2e in 64% yield with an 8:92 meta:para selectivity. Adding methyl substituents (1f) increased the yield to 71%. With phenyl substituents, the poorly soluble 1g was borylated in 59% yield with similar selectivity (89% para).

Surprisingly, diphenylacetylene 1h showed poor reactivity (17%).

Scheme 2 Electrophilic borylation of arenes 1a–ah and formation of the aryl-boratriptycenes ate-complexes 2a–ah. Products for which the initial substrate is solid are highlighted in light gray. Yields refer to those of purified, isolated products.

Substrates bearing primary (1i–k), secondary (1l–n), or tertiary (1o) alkyl groups were borylated with mostly good yields. In all cases, the regioselectivity for para-borylation was higher than for the meta one (84–98%). The 1,1-disubstituted arene 1p was selectively borylated in 76% yield. We then investigated the influence of 1,3-substitution starting with methyl substituents. This selectively afforded the desired meta-borylated product 2q in 85% yield. Increasing the steric hindrance using ethyl (1r) and isopropyl (1s) reduced the yield to 77% and 69%, respectively, with the same regioselectivity.

The reaction tolerated diaryl ethers, such as 1t, which afforded the desired borylated ether 2t in 65% yield and gave the highest observed regioselectivity (99% para).

We then decided to incorporate deactivating halogen substituents into the methylated 1p and 1q scaffolds. To our delight, these push-pull (+I/−I) combinations showed almost no modification for the 1,2-methyl system (1u), with 2u obtained in 65% yield. Concerning the halogenated analogues 1v–w of 1q, this reduced the yield from 85% to 57%, as expected from the addition of a deactivating group para to the reactive position. We then investigated more electron-poor arenes 1x-ah with the conditions optimized for chlorobenzene (80 equiv of arene). Haloarenes 1x-aa were all borylated with decent to good yields. Going down the halogen series, the +M effect decreases. As a result, the para/meta selectivity decreases from chloride to iodide (80% para for 2x to 67% for 2aa). Fluorine is the only substituent so far small enough to enable ortho borylation with our system. As for dibenzothiophene 1d, the two meta and para positions of 1ab were borylated in the same ratio, with 65% total yield. The 1,3-disubstituted isomer 1ac led to a reduced yield of 23% with complete regioselectivity for the meta position. In general, regioselectivities were higher than those reported in other undirected, metal-free electrophilic C(sp²)–H borylation reactions with classical borenium ions, which are smaller borylating species than boratriptycene.[9] The latter precludes ortho (except for fluorine) and minimizes meta borylation.

We also succeeded in the borylation of dihaloarenes 1ad–ah. For these strongly deactivated substrates, yields below 30% were obtained.

Mechanistic Investigations and Control Experiments

The mechanism of the protodeborylation reaction of 1 occurring via protonation at the carbon atom of the C−B bond connecting the boratriptycene and the mesityl group with the bistriflimidic acid HNTf₂ was investigated by NMR spectroscopy in toluene-d ₈ ([Scheme 3]). Mixing 1 with a substoichiometric or excess amounts of HNTf₂ led to the immediate formation of two previously reported species: the O-ligated triflimidate boratriptycene sulfonium 3 [10] and the triflimidate-bridged dimer 3′ (see the SI, pages 9–11).[11]

Scheme 3 Investigation of the protodeborylation of 1 with bistriflimidic acid HNTf₂ and formation of 3 and of the dimer 3′.

No N-ligated isomer in which the nitrogen atom of NTf₂ ⁻ is connected to the boron atom of the pyramidal boron Lewis superacid was formed, and only trace amounts of unknown species were observed. Performing ¹H and ¹⁹F NMR analysis of the reaction medium over extended time revealed, in both cases, a slow conversion of the bridged dimer 3′ into 3, which is supposed to be the thermodynamic product.

In the absence of the sodium salt NaB(C₆F₅)₄, the triflimidate-boratriptycene species 3 and 3′ are not competent for C(sp²)–H borylation. To rationalize the key role of NaB(C₆F₅)₄, we mixed 1, HNTf₂, and NaB(C₆F₅)₄ ([Scheme 3], bottom panel). Following this reaction by ¹⁹F NMR analysis over time showed that, contrary to the “salt-free” conditions (i.e., without NaB(C₆F₅)₄), the dimer 3′ amount increased slowly, reaching a 3:3′ ratio of 85:15 after 16 h. After 40 h, numerous signals were observed in the NMR spectra, suggesting a decomposition of the B(C₆F₅)₄ anion.

We then investigated 3:3′ equilibrium, starting from isolated pure 3. Mixing the latter and HNTf₂ (1 equiv) did not lead to any reaction, even after 16 h ([Scheme 4A]).

Scheme 4 Evaluation of the reversibility of 3:3′ equilibrium.

Conversely, mixing 3 and NaB(C₆F₅)₄ (1 equiv) led to a slow dimerization, and 3′ was detected by ¹⁹NMR after 16 h ([Scheme 4B]). From this, we infer that the addition of sodium cation allows the displacement of the equilibrium between 3 and 3′, implying coordination/decoordination sequences of the triflimidate on the boron center. The decoordination of the triflimidate anion from the boron atom of 3 may be due to the sodium cation chelating the oxygen atom of each of its sulfone group, forming a cyclic bidentate NaNTf₂ complex,[12] which is insoluble and precipitates, potentially allowing a very slow and continuous release of the uncomplexed pyramidal boron Lewis superacid, which could perform the C(sp²)–H borylation reactions (see mechanism proposal in [Scheme 7]).

Surprisingly, while a range of sterically hindered Brønsted bases are suitable for rearomatization by proton transfer during the reaction (see Table S1 in the Supporting Information), we found that bases which are not sterically shielded around the Lewis basic site, such as N,N-3,5-tetramethylaniline (TMA), are also suitable. To elucidate the dual role of TMA as Lewis and Brønsted base, we first generated the sulfonium-10-boratriptycene Lewis adduct 4, which turned out to be very stable in solution ([Scheme 5A], see NMR characterization in the SI).

Scheme 5 Investigation of the association of the N,N-3,5-tetramethylaniline (TMA) with the 9-bora-10-sulfonium triptycene.

The Lewis adducts 4 did not perform the C(sp²)–H borylation of benzene, regardless of the reaction conditions. Addition of the triflimidate complex 3 to the solution is necessary to observe the borylation of benzene ([Scheme 5B]). Importantly, 48% of the borylation product 2ai is obtained based on the initial amount of 1, meaning that more 2ai is produced than 3 was added. Therefore, the B–N bond in 4 is dissociated in the presence of 3.

As some sodium salts are still present, 3 can dimerize to 3′ and the B–N bond dissociation in 4 can also be mediated by 3′.

Kinetic isotope effect (KIE) experiments were conducted, varying the substrate nucleophilicity ([Scheme 6]). The observed KIEs were relatively small (~1.2) for both benzene and 1,2-dichlorobenzene. Therefore, deprotonation is not the rate-determining step in the overall mechanism of the borylation reaction.

Scheme 6 Kinetic isotopic effect (KIE) for the electrophilic C(sp²)−H borylation of benzene and 1,2-dichlorobenzene using TMA as base.

From the previous experiments, the proposed mechanism can be found in [Scheme 7]. First, the strong Brønsted acid HNTf₂ selectively protonates the most electron-rich arene of 1 (the mesityl ring), which is followed by protodeborylation, giving mesitylene and a mixture of 3 and 3′. In the absence of additives, 3′ converts to the more stable 3, but in the presence of a superstoichiometric amount of NaB(C₆F₅)₄, the precipitation of NaNTf₂ displaces the equilibrium in favor of 3′-B(C ₆ F ₅ ) ₄ ([Scheme 3]). This species can be seen as a reservoir of highly electrophilic Lewis acid such as 3″, which is well suited to react with arenes, giving 2-H. In the absence of arene, or when the arene is not reactive enough, the Lewis adduct 4 is the principal product ([Scheme 5A]). Although very stable, this adduct does not constitute a dead-end for the reaction, as it can be dissociated, probably by reacting with the key reservoir species 3′-B(C ₆ F ₅ ) ₄. Finally, 2-H is deprotonated irreversibly, enabling its rearomatization to the product 2. Thus, 3′-B(C ₆ F ₅ ) ₄ can be considered as a “masked” or latent Lewis superacid, which, upon heating, generates slowly and continuously a highly electrophilic trivalent pyramidal boron Lewis acid in solution.

Scheme 7 Proposed mechanism for the electrophilic C(sp²)–H borylation of aromatics with 9-bora-10-sulfonium triptycene.

Both the mesityl group of 1 and our base of choice (TMA) are 1,3,5-trisubstituted arenes. This is crucial to the reaction design, as these types of substrates are inert toward our C(sp²)–H borylation reaction (see [Scheme 2]). Indeed, neither mesitylene (even when used as a reagent in large excess or as solvent) nor TMA undergo electrophilic C–H borylation, despite being electron-rich aromatics, as their aromatic C–H bonds are sterically protected by two substituents in the ortho positions. As such, protodeborylation of 1 is thus fully irreversible, and the generation of a pyramidal boron Lewis acid in solution initiates the entire borylation process.

Conclusion

We have developed an improved electrophilic C(sp²)–H borylation methodology that significantly reduces substrate requirements while expanding the scope to include solid aromatics.

The method provides excellent regioselectivity across diverse substrate classes, with mechanistic studies revealing the involvement of multiple equilibrating boron species. This work advances the practical utility of transition-metal-free aromatic borylation and provides mechanistic insights for future method development. Quantum-chemical calculations are underway to obtain a detailed reaction-energy profile, and further derivatization of these borate complexes is under investigation in our laboratory.

Experimental Section

NMR spectra were recorded on 400- or 500-MHz JEOL NMR spectrometers. The observed signals are reported in parts per million (ppm) relative to the residual signal of the nondeuterated solvent for ¹H and ¹³C NMR spectra. The following abbreviations are used to describe multiplicities s = singlet, d = doublet, t = triplet, q = quartet, quin = quintuplet, br = broad, m = multiplet. The external references considered as 0.0 ppm are boron trifluoride etherate (BF₃ ^.Et₂O) for ¹¹B NMR, trichloromonofluoromethane (CFCl₃) for ¹⁹F NMR, and H₃PO₄ (85%) for ³¹P NMR. Flash chromatography was performed using silica gel Silica Flash® 40–63 μm (230–400 mesh) from Sigma-Aldrich. TLC detection was accomplished by irradiation with a UV lamp at 265 or 313 nm. Melting points were determined on a Büchi B-545 device and are not corrected. Infrared spectra were recorded on a PerkinElmer FT-IR Spectrometer. UV–vis absorption spectra were recorded on a Cary 5000 UV–vis–NIR Spectrophotometer. Photoluminescence spectra were recorded on a Cary Eclipse Fluorescence Spectrophotometer. In some cases, HRMS were detected as the sum of the desired product and trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene] malononitrile, a constituent of the matrix.

4 Å molecular sieves were dried at 400 °C under high vacuum for 3 days and stored in a high-performance glove box. Diethyl ether, tetrahydrofuran, toluene, and dichloromethane were dried with an MBraun solvent-purification system and stored under argon. Other reagents and chemicals were purchased from Sigma-Aldrich, Alfa Aesar, TCI, and Fluorochem and used without further purification. Unless otherwise stated, all the reactions were performed under an atmosphere of argon using classical Schlenk-line techniques or in a high-performance glovebox.

Procedures

General Procedure for the Electrophilic C–H Borylation of Volatile Aromatic Substrates (GP1)

In an argon-filled glovebox, HNTf₂ (40 mg, 0.14 mmol, 1.1 equiv) was added to a Schlenk tube containing a suspension of 10-mesityl-9-sulfonium-10-boratritpyceneate complex 1 (50 mg, 0.13 mmol, 1.0 equiv) in 1,2,3,4-tetrafluorobenzene (3.0 mL) or 1,3,5-trifluorobenzene (3.0 mL). The reaction was stirred for 5 min, then NaB(C₆F₅)₄ (139 mg, 0.19 mmol, 1.5 equiv) was added, and the reaction mixture was stirred for a further 5 min. TMA (105 μL, 0.64 mmol, 5.0 equiv) and the aromatic substrate were added. The Schlenk tube was then sealed with a glass stopper, stirred, and warmed in an oil bath at 60 °C. After 16 h, the volatiles were removed, and the crude was dissolved in CH₂Cl₂, after which trifluoroacetic acid (54 μL, 0.70 mmol, 5.5 equiv) was added, and the solution was filtered over silica-gel plug. The filtrate was evaporated to dryness and purified via flash chromatography (90:10 n-hexane/CH₂Cl₂), affording pure 10-aryl-9-sulfonium-10-boratriptycene-ate complex as colorless powder.

General Procedure for the Electrophilic C–H Borylation for Solid Aromatics and Nonvolatile Aromatic Substrates (GP2)

In an argon-filled glovebox, HNTf₂ (40 mg, 0.14 mmol, 1.1 equiv) was added to a Schlenk tube containing a suspension of 10-mesityl-9-sulfonium-10-boratritpyceneate complex 1 (50 mg, 0.13 mmol, 1.0 equiv) in 1,2,3,4-tetrafluorobenzene (3.0 mL) or 1,3,5-trifluorobenzene (3.0 mL). The reaction was stirred for 5 min, then NaB(C₆F₅)₄ (139 mg, 0.19 mmol, 1.5 equiv) was added, and the reaction mixture was stirred for a further 5 min. TMA (105 μL, 0.64 mmol, 5.0 equiv) and the aromatic substrate were added. The Schlenk tube was then sealed with a glass stopper, stirred, and warmed in an oil bath at 60 °C. After 16 h, the volatiles were removed, and the crude was dissolved in CH₂Cl₂, after which trifluoroacetic acid (54 μL, 0.70 mmol, 5.5 equiv) was added and the solution was filtered over silica-gel plug. The filtrate was evaporated to dryness then adsorbed on silica and settled on a silica-gel plug. The silica was thoroughly washed with a mixture of n-hexane and CH₂Cl₂ (98:2). The removal of excess aromatic substrate was monitored by TLC. Once the excess aromatic substrate was removed, the silica-gel plug was washed with pure CH₂Cl₂ and the filtrate was recovered. The crude was then purified via flash chromatography (90:10 n-hexane/CH₂Cl₂) affording pure 10-aryl-9-sulfonium-10-boratriptycene-ate complex as colorless powder.

10-Phenyl-9-sulfonium-10-boratriptycene-ate Complex 2a

According to GP1 with the following quantities of benzene (343 μL, 3.8 mmol, 30 equiv). Colorless powder, yield: 85%. The ¹H, ¹³C, and ¹¹B NMR data are identical to the previously reported ones.[7]

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.10 (d, J = 6.9 Hz, 2H), 7.86 (d, J = 7.3 Hz, 3H), 7.77 (d, J = 7.6 Hz, 3H), 7.56 (t, J = 7.5 Hz, 2H), 7.39 (t, J = 7.3 Hz, ¹H), 7.23 (td, J =7.4, 1.2 Hz, 3H), 7.06 (td, J = 7.5, 1.4 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 135.8 (CH), 134.5 (CH), 134.3 (CH), 130.2 (CH), 127.7 (CH), 124.9 (CH), 224.2 (CH). The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

10-(2-Naphtyl)-9-sulfonium-10-boratriptycene-ate Complex 2b

According to GP2 with the following quantities of naphthalene (492 mg, 3.8 mmol, 30 equiv). Yield: 82%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.67 (s, ¹H), 8.14 (d, J = 8.2 Hz, ¹H), 8.00 (d, J = 8.3 Hz, ¹H), 7.98–7.93 (m, 2H), 7.90 (d, J = 7.3 Hz, 3H), 7.80 (dd, J = 7.7, 0.9 Hz, 3H). 7.54–7.46 (m, 2H), 7.24 (td, J = 7.5, 1.1 Hz, 3H), 7.09 (td, J = 7.5, 1.4 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.9 (CB), 135.0 (CH), 134.5 (Cq), 134.3 (CH), 134.1 (Cq), 134.0 (CH), 132.1 (Cq), 130.3 (CH), 128.1 (CH), 127.8 (CH), 127.7 (CH), 126.1 (CH), 125.0 (CH), 124.7 (CH), 124.3 (CH).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.1 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C28H19BNaS⁺]: 421.1198, [M⁺]: 421.1206.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 1498, 1429, 1297, 1256, 1170, 1124, 946, 905, 810, 741.

M.p.: >300 °C.

10-(2-Anthracyl)-9-sulfonium-10-boratriptycene-ate Complex 2c

According to GP2 with the following quantities of anthracene (686 mg, 3.8 mmol, 30 equiv). Yield: 85%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.89 (s, ¹H), 8.55 (d, J = 14.7 Hz, 2H), 8.16 (d, J = 8.5 Hz, ¹H), 8.13–8.04 (m, 3H), 7.96 (d, J = 7.2 Hz, 3H), 7.81 (dd, J = 7.6, 0.9 Hz, 3H), 7.48–7.43 (m, 2H), 7.26 (td, J = 7.4, 1.1 Hz, 3H), 7.10 (td, J = 7.5, 1.4 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.8 (CB), 135.1 (CH), 134.5 (Cq), 134.4 (CH), 133.6 (CH), 132.9 (Cq), 131.7 (Cq), 131.4 (Cq), 131.2 (Cq), 130.3 (CH), 128.4 (CH), 128.3 (CH), 127.8 (CH), 126.0 (CH), 126.0 (CH), 125.7 (CH), 125.6 (CH), 124.8 (CH), 124.6 (CH), 124.3 (CH), 120.5 (CH), 119.6 (CH), 110.7 (CH).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.1 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C32H21BNaS⁺]: 471.1355, [M⁺]: 471.1347

IR (neat, ATR): ṽ/cm⁻¹ = 3043, 2961, 2924, 1589, 1507, 1457, 1425, 1293, 1270, 1161, 1083, 978, 869, 746.

M.p.: 291 °C (dec).

10-(2-Dibenzothiophene)-9-sulfonium-10-boratriptycene-ate Complex 2d

According to GP2 with the following quantities of dibenzothiophene (354 mg, 1.9 mmol, 15 equiv). Product obtained as inseparable mixture of two regioisomers (2-:3–50:50). Yield: 48%.

TLC: R _f = 0.8 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (2-isomer) 8.63 (s, ¹H), 8.35 (d, J = 8.0 Hz, ¹H), 8.16 (d, J = 8.0 Hz, ¹H), 8.28–8.25 (m, ¹H), 7.95–7.87 (m, 4H), 7.83–7.79 (m, 3H), 7.50–7.42 (m, 2H), 7.26 (tt, J = 7.3, 1.1 Hz, 3H), 7.10 (td, J = 7.5, 1.3 Hz, 3H). (3-isomer) 8.95 (s, ¹H), 8.20 (d, J = 8.2 Hz, ¹H), 8.05 (d, J = 8.0 Hz, ¹H), 7.95–7.87 (m, 4H), 7.83–7.79 (m, 3H), 7.50–7.42 (m, 2H), 7.09 (td, J = 7.5, 1.3 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 132.6 (CB), 139.5 (Cq), 139.3 (Cq), 136.7 (Cq), 136.7 (Cq), 136.3 (Cq), 135.4 (CH), 135.1 (CH), 134.5 (Cq), 134.4 (Cq), 134.2 (CH), 132.9 (CH), 132.4 (CH), 130.3 (CH), 129.2 (CH), 129.1 (CH), 128.5 (CH), 128.4 (CH), 127.9 (CH), 127.8 (CH), 126.1 (CH), 126.0 (CH), 124.3 (CH), 124.2 (CH), 124.1 (CH), 123.0 (CH), 123.0 (CH), 121.9 (CH), 121.6 (CH), 121.3 (CH), 120.7 (CH).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.0 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C30H19BNaS2+]: 477.0919, [M⁺]: 477.0926.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 2965, 2920, 1644, 1589, 1507, 1452, 1420, 1261, 1165, 1129, 1088, 974, 869, 746.

M.p.: 278–283 °C.

10-(4-Biphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2e

According to GP2 with the following quantities of biphenyl (593 mg, 3.8 mmol, 30 equiv).

Product obtained as inseparable mixture of two regioisomers (m:p 08:92) Yield: 64%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.19 (d, J = 7.5 Hz, 2H), 7.92 (d, J = 7.4 Hz, 3H), 7.84 (t, J = 7.2 Hz, 4H), 7.79 (d, J = 7.7 Hz, 3H), 7.51 (t, J = 7.3 Hz, 2H), 7.37 (td, J = 7.6, 1.1 Hz, ¹H), 7.26 (t, J = 7.4 Hz, 3H), 7.09 (t, J = 7.5 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.8 (CB), 142.2 (Cq), 137.4 (Cq), 136.2 (CH), 134.5 (Cq), 134.3 (CH), 130.2 (CH), 128.8 (CH), 127.8 (CH), 127.2 (CH), 126.7 (CH), 126.3 (CH), 124.3 (CH).¹¹B NMR (160 MHz, CDCl₃) δ (ppm) = −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C32H21BNaS⁺]: 471.1355, [M⁺]: 471.1359.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 1484, 1434, 1302, 1261, 1193, 1115, 1010, 892, 750.

M.p.: 283–285 °C.

10-(5-(3,3′-Dimethylbiphenyl))-9-sulfonium-10-boratriptycene-ate Complex 2f

According to GP2 with the following quantities of 3,3′-dimethylbiphenyl (700 mg, 3.8 mmol, 30 equiv). Yield: 71%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.10 (s, ¹H), 7.96 (s, ¹H), 7.93 (d, J = 6.8 Hz, 3H), 7.78 (dd, J = 7.6, 0.8 Hz, 3H), 7.56–7.53 (m, 2H), 7.46–7.44 (m, ¹H), 7.33 (t, J = 8.0 Hz, ¹H), 7.25 (td, J = 7.4, 1.2 Hz, 3H), 7.14 (d, J = 7.5 Hz, ¹H), 7.08 (td, J = 7.5, 1.4 Hz, 3H), 2.58 (s, 3H), 2.42 (s, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.2 (CB), 143.3 (Cq), 140.3 (Cq), 138.1 (Cq), 137.0 (Cq), 135.5 (CH), 134.5 (Cq), 134.4 (CH), 132.0 (CH), 130.3 (CH), 128.6 (CH), 128.4 (CH), 127.7 (CH), 127.4 (CH), 124.8 (CH), 124.7 (CH), 124.2 (CH), 22.3 (CH₃), 21.8 (CH₃).

¹¹B NMR (160 MHz, CDCl₃):: δ (ppm) = −9.1 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C32H25BNaS⁺]: 475.1668, [M⁺]: 475.1663.

IR (neat, ATR): ṽ/cm⁻¹ = 3029, 1580, 1425, 1297, 1256, 1165, 1120, 955, 869, 787, 741.

M.p. :187–188 °C.

10-(4-Triphenylbenzene)-9-sulfonium-10-boratriptycene-ate Complex 2g

According to GP2 with the following quantities of triphenylbenzene (785 mg, 2.5 mmol, 20 equiv).

Product obtained as inseparable mixture of two regioisomers (m:p 11:89) Yield: 59%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.23 (d, J = 8.0 Hz, 2H), 8.04 (d, J = 1.7 Hz, 2H), 7.97–7.92 (m, 5H), 7.83 (dt, J = 1.7 Hz, ¹H), 7.83–7.78 (m, 7H), 7.53 (t, J = 7.7 Hz, 4H), 7.42 (tt, J = 7.4, 1.2 Hz, 2H), 7.2 (td, J = 7.4, 1.2 Hz, 3H), 7.09 (td, J = 7.5, 1.3 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.7 (CB), 143.3 (Cq), 142.3 (Cq), 141.6 (Cq), 137.3 (Cq), 136.2 (CH), 134.4 (Cq), 134.2 (CH), 130.2 (CH), 128.9 (CH), 127.8 (CH), 127.5 (CH), 127.5 (CH), 126.4 (CH), 125.2 (CH), 124.6 (CH), 124.2 (CH).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.2 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C42H29BKS⁺]: 615.1720, [M⁺]: 615.1710.

IR (neat, ATR): ṽ/cm⁻¹ = 3052, 2910, 1584, 1498, 1425, 1293, 1256, 1199, 1015, 887, 746.

M.p.: 296 °C (dec).

10-(4-Diphenylacetylene)-9-sulfonium-10-boratriptycene-ate Complex 2h

According to GP2 with the following quantities of diphenylacetylene (685 mg, 3.8 mmol, 30 equiv). Product obtained as inseparable mixture of two regioisomers (m:p 12:88) Yield: 17%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.09 (d, J = 8.0 Hz, 2H), 7.83 (dd, J = 7.4, 0.9 Hz, 3H), 7.78 (dd, J = 7.7, 0.9 Hz, 3H), 7.73 (d, J = 8.2 Hz, 2H), 7.63–7.59 (m, 2H), 7.40–7.32 (m, 3H), 7.25 (td, J = 7.4, 1.2 Hz, 3H), 7.08 (td, J = 7.5, 1.5 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.5 (CB), 135.7 (CH), 134.4 (Cq), 134.1 (CH), 131.8 (CH), 131.7 (CH), 130.8 (CH), 130.3 (CH), 128.4 (CH), 127.9 (CH), 127.8 (CH), 124.3 (CH), 119.3 (Cq), 91.0 (Cq), 88.3 (Cq).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C32H21BNaS⁺]: 471.1355, [M⁺]: 471.1351.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 2920, 1589, 1484, 1429, 1297, 1220, 1165, 1024, 892, 855, 810, 750.

M.p.: 254–257 °C.

10-(4-Octylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2i

According to GP2 with the following quantities of octylbenzene (852 μL, 3.8 mmol, 30 equiv).

Product obtained as inseparable mixture of two regioisomers (m:p 02:98) Yield: 59%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.01 (d, J = 7.7 Hz, 2H), 7.87 (d, J = 6.8 Hz, 3H), 7.77 (dd, J = 7.6, 0.7 Hz, 3H), 7.39 (d, J = 7.9 Hz, 2H), 7.23 (td, J = 7.4, 1.1 Hz, 3H), 7.06 (td, J = 7.5, 1.3 Hz, 3H), 2.79–2.74 (m, 2H), 1.84–1.75 (m, 2H), 1.52–1.45 (m, 2H), 1.45–1.30 (m, 8H), 0.92 (t, J = 6.9 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.5 (CB), 139.2 (Cq), 135.6 (CH), 134.4 (Cq), 134.3 (CH), 130.1 (CH), 127.7 (CH), 127.7 (CH), 124.1 (CH), 36.1 (CH2), 32.1 (CH2), 31.9 (CH2), 29.8 (CH2), 29.7 (CH2), 29.5 (CH2), 22.8 (CH2), 14.3 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C32H33BNaS⁺]: 483.2294, [M⁺]: 483.2285.

IR (neat, ATR): ṽ/cm⁻¹ = 2924, 2847, 1434, 1293, 1261, 1183, 1115, 1040, 896, 750.

M.p.: Could not be determined.

10-(4-Bibenzyl)-9-sulfonium-10-boratriptycene-ate Complex 2j

According to GP2 with the following quantities of bibenzyl (700 mg, 3.8 mmol, 30 equiv).

Product obtained as inseparable mixture of two regioisomers (m:p 07:93) Yield: 66%

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.04 (d, J = 7.7 Hz, 2H), 7.88 (d, J = 7.3 Hz, 3H), 7.78 (d, J = 7.7 Hz, 3H), 7.43 (d, J = 7.8 Hz, 2H), 7.38–7.32 (m, 4H), 7.25 (td, J = 7.4, 1.0 Hz, 3H), 7.07 (td, J = 7.5, 1.3 Hz, 3H), 3.15–3.06 (m, 4H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.3 (CB), 142.7 (Cq), 138.1 (Cq), 135.8 (CH), 134.4 (Cq), 134.3 (CH), 130.1 (CH), 128.7 (CH), 128.5 (CH), 128.4 (CH), 127.8 (CH), 127.7 (CH) 125.9 (CH), 124.2 (CH), 38.4 (CH2), 38.2 (CH2).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C32H25BNaS⁺]: 475.1668, [M⁺]: 475.1667.

IR (neat, ATR): ṽ/cm⁻¹ = 3038, 2920, 1493, 1439, 1293, 1256, 1179, 1019, 901, 801, 750.

M.p.: 245–248 °C.

10-(4-Diphenylmethane)-9-sulfonium-10-boratriptycene-ate Complex 2k

According to GP2 with the following quantities of diphenylmethane (950 mg, 3.8 mmol, 30 equiv).

Product obtained as inseparable mixture of two regioisomers (m:p 16:84) Yield: 65%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (p-isomer) 8.02 (d, J = 7.8 Hz, 2H), 7.86 (J = 6.8 Hz, 3H), 7.77 (dd, J = 7.7, 0.8 Hz, 3H), 7.43–7.35 (m, 5H), 7.28–7.25 (m, 2H), 7.23 (dt, J = 7.4, 1.1 Hz, 3H), 7.06 (td, J = 7.5, 1.4 Hz, 3H), 4.15 (s, 2H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.1 (CB), 142.2 (Cq), 137.3 (Cq), 135.8 (CH), 134.4 (Cq), 134.3 (CH), 130.1 (CH), 129.3 (CH), 128.5 (CH), 128.2 (CH), 127.7 (CH), 126.0 (CH), 124.2 (CH), 42.1 (CH2).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C3¹H23BNaS⁺]: 461.1511, [M⁺]: 461.1502.

IR (neat, ATR): ṽ/cm⁻¹ = 3052, 2965, 2929, 1648, 1589, 1521, 1420, 1270, 1179, 1129, 1088, 978, 878, 750.

M.p.: 216–219 °C.

10-(4-Isopropylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2l

According to GP1 with the following quantities of isopropylbenzene (536 μL, 3.8 mmol, 30 equiv). Product obtained as inseparable mixture of two regioisomers (m:p 15:85). Yield: 53%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (m-isomer) 7.95 (d, J = 6.3 Hz, 2H), 7.77 (dd, J = 7.6, 0.9 Hz, 3H), 7.72 (t, J = 7.8 Hz, 2H), 7.51 (t, J = 7.7 Hz, ¹H), 7.24 (dt, J = 7.3, 1.2 Hz, 3H), 7.07 (td, J = 7.5, 1.4 Hz, 3H), 3.07 (hept, J = 6.9 Hz, ¹H), 1.39 (d, J = 6.9 Hz). (p-isomer) 8.03 (d, J = 7.8 Hz, 2H), 7.88 (d, J = 7.3 Hz, 3H), 7.77 (dd, J = 7.6, 0.9 Hz, 3H), 7.44 (d, J = 7.7 Hz, 2H), 7.24 (td, J = 6.7, 1.2 Hz, 3H), 7.06 (td, J = 7.4, 1.4 Hz, 3H), 3.07 (hept, J = 6.9 Hz, ¹H), 1.42 (d, J = 6.9 Hz, 6H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.1 (CB), 145.0 (Cq), 135.6 (CH), 134.5 (Cq), 134.4 (CH), 130.1 (CH), 127.7 (CH), 125.7 (CH), 124.1 (CH), 34.0 (CH), 24.4 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C27H23BNaS⁺]: 413.1511, [M⁺]: 413.1507

IR (neat, ATR): ṽ/cm⁻¹ = 3052, 2956, 1434, 1306, 1261, 1179, 1010, 892, 750.

M.p.: 211–214 °C.

10-(4-(4-Secbutylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2m

According to GP1 with the following quantities of secbutylbenzene (598 μL, 3.8 mmol, 30 equiv).

Product obtained as inseparable mixture of two regioisomers (m:p 07:93) Yield: 25%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 7.99 (d, J = 7.6 Hz, 2H), 7.86 (d, J = 7.2 Hz, 3H), 7.76 (d, J = 7.5 Hz, 3H), 7.37 (d, J = 7.9 Hz, 2H), 7.23 td, J = 7.3, 0.9 Hz, 3H), 7.05 (td, J = 7.5, 1.2 Hz, 3H), 2.72 (sext, J = 7.0 Hz, ¹H), 1.83–1.63 (m, 2H), 1.39 (d, J = 7.0 Hz, 3H), 0.97 (t, J = 7.4 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.6 (CB), 143.8 (Cq), 135.5 (CH), 134.4 (Cq), 134.3 (CH), 130.0 (CH), 127.6 (CH), 126.3 (CH), 124.1 (CH), 41.5 (CH), 31.6 (CH2), 21.9 (CH₃), 12.7 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = (m-isomer) −9.0 (s), (p-isomer) −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C28H25BNaS⁺]: 427.1668, [M⁺]: 427.1659.

IR (neat, ATR): ṽ/cm⁻¹ = 3043, 2951, 2860, 1434, 1297, 1265, 1188, 1010, 896, 750.

M.p.: 264–265 °C (dec).

10-(4-Cyclohexylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2n

According to GP1 with the following quantities of cyclohexylbenzene (648 μL, 3.8 mmol, 30 equiv).

Product obtained as inseparable mixture of two regioisomers (m:p 05:95).

Yield: 65%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.01 (d, J = 7.8 Hz, 2H), 7.87 (d, J = 6.7 Hz, 3H), 7.76 (dd, J = 7.6, 0.8 Hz, 3H), 7.41 (d, J = 7.9 Hz, 2H), 7.23 (td, J = 7.3, 1.1 Hz, 3H), 7.06 (td, J = 7.5, 1.4 Hz, 3H), 2.65 (tt, J = 11.9, 3.3 Hz, ¹H), 2.09 (d, J = 11.6 Hz, 2H), 1.90 (dt, J = 12.9, 3.1 Hz, 2H), 1.81 (d, J = 12.8 Hz, ¹H), 1.61 (dq, J = 12.5, 2.9 Hz, 2H), 1.49 (tq, J = 12.8, 3.2 Hz, 2H), 1.34 (tq, J = 12.8, 3.6 Hz, ¹H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.2 (CB), 144.3 (Cq), 135.6 (CH), 1344 (Cq), 134.3 (CH), 130.1 (CH), 127.7 (CH), 126.1 (CH), 124.1 (CH), 44.5 (CH), 34.9 (CH2), 27.3 (CH2), 26.6 (CH2).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C30H27BNaS⁺]: 453.1824, [M⁺]: 453.1828.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 2915, 2847, 1580, 1507, 1457, 1293, 1193, 1010, 869, 750.

M.p.: 250–252 °C.

10-(4-(4-Terbutylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2o

According to GP1 with the following quantities of terbutylbenzene (597 μL, 3.8 mmol, 30 equiv).

Product obtained as inseparable mixture of two regioisomers (m:p 12:88) Yield: 64%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (m-isomer) 8.12 (s, ¹H), 7.97 (d, J = 7.3 Hz, ¹H), 7.88–7.86 (m, 3H), 7.80–7.76 (m, 3H), 7.72 (dd, J = 7.5, 1.1 Hz, ¹H), 7.53 (t, J = 7.5 Hz, ¹H), 7.44 (d, J = 7.8 Hz, ¹H), 7.27–7.22 (m, 3H), 7.10–7.05 (m, 3H), 1.45 (s, 9H). (p-isomer) 8.03 (d, J = 8.0 Hz, 2H), 7.89 (d, J = 7.4 Hz, 3H), 7.61–7.58 (m, 2H), 7.24 (td, J = 7.4, 1.2 Hz, 3H), 7.06 (td, J = 7.5, 1.4 Hz, 3H), 1.49 (s, 9H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.3 (CB), 147.2 (Cq), 135.4 (CH), 134.4 (Cq), 134.4 (CH), 130.1 (CH), 127.7 (CH), 124.5 (CH), 124.1 (CH), 34.6 (Cq), 31.8 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = (m-isomer) −9.0 (s), (p-isomer) −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C28H25BNaS⁺]: 427.1668, [M⁺]: 427.1662.

IR (neat, ATR): ṽ/cm⁻¹ = 2947, 2869, 1489, 1416, 1265, 1202, 1120, 1019, 869, 846, 814, 750.

M.p.: 242–249 °C.

10-(4-(3,4-Dimethylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2p

According to GP1 with the following quantities of o-xylene (464 μL, 3.8 mmol, 30 equiv). Yield: 76%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 7.93–7.88 (m, 4H), 7.84 (d, J = 7.3 Hz, ¹H), 7.77 (dd, J = 7.6, 0.6 Hz, 3H), 7.36 (d, J = 7.4 Hz, ¹H), 7.24 (td, J = 7.5, 1.1 Hz, 3H), 7.06 (td, J = 7.5, 1.4 Hz, 3H), 2.45 (s, 3H), 2.44 (s, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.3 (CB), 137.2 (CH), 135.3 (Cq), 134.5 (Cq), 134.4 (CH), 133.4 (CH), 132.7 (Cq), 130.1 (CH), 129.1 (CH), 127.7 (CH), 124.1 (CH), 20.4 (CH₃), 19.8 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C26H21BNaS⁺]: 399.1355, [M⁺]: 399.1354.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 1493, 1420, 1297, 1252, 1202, 1124, 1010, 937, 805, 750.

M.p. :266–268 °C.

10-(5-(1,3-Dimethylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2q

According to GP1 with the following quantities of m-xylene (475 μL, 3.8 mmol, 30 equiv). [S1].

Yield: 85%.

The ¹H, ¹³C, and ¹¹B NMR data are identical to that previously reported.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 7.89 (d, J = 7.4 Hz, 3H), 7.76 (d, J = 7.6 Hz, 3H), 7.73 (s, 2H), 7.25 (t, J = 7.3 Hz, 3H), 7.09–7.04 (m, 4H), 2.48 (s, 6H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.0 (CB), 136.6 (Cq), 134.5 (Cq), 134.5 (CH), 133.6 (CH), 130.2 (CH), 127.7 (CH), 126.6 (CH), 124.2 (CH), 22.1 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.3 (s).

10-(3,5-Diethylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2r

According to GP1 with the following quantities of 1,3-diethylbenzene (597 μL, 3.8 mmol, 30 equiv). Yield: 77%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 7.91 (d, J = 7.3 Hz, 3H), 7.82–7.77 (m, 5H), 7.25 (td, J = 7.4, 0.5 Hz, 3H), 7.10 (s, ¹H), 7.07 (td, J = 7.3, 0.9 Hz, 3H), 2.81 (q, J = 7.6 Hz, 4H), 1.39 (t, J = 7.6 Hz, 6H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.2 (CB), 143.0 (Cq), 134.5 (CH), 134.5 (CH), 132.8 (CH), 130.1 (CH), 127.7 (CH), 124.1 (CH), 124.0 (CH), 29.6 (CH2), 16.3 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.1 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C28H25BNaS⁺]: 427.1668, [M⁺]: 427.1674

IR (neat, ATR): ṽ/cm⁻¹ = 2961, 2920, 1648, 1589, 1507, 1461, 1411, 1275, 1170, 1092, 978, 878, 755.

M.p.: 209–212 °C.

10-(3,5-Diisopropylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2s

According to GP1 with the following quantities of 1,3-diisopriopylbenzene (729 μL, 3.8 mmol, 30 equiv). Yield: 69%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 7.89 (d, J = 7.0 Hz, 3H), 7.80 (s, 2H), 7.77 (dd, J = 7.6, 0.8 Hz, 3H), 7.25 (td, J = 7.4, 1.3 Hz, 3H), 7.11 (t, J = 1.6 Hz, ¹H), 7.07 (td, J = 7.5, 1.4 Hz, 3H), 3.05 (hept, J = 6.9 Hz, 2H), 1.39 (d, J = 6.9 Hz, 12H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.3 (CB), 147.4 (Cq), 134.5 (CH), 131.4 (CH), 130.1 (CH), 130.1 (CH), 127.7 (CH), 124.1 (CH), 121.0 (CH), 34.7 (CH), 24.6 (CH₃).¹¹B NMR (160 MHz, CDCl₃) δ (ppm) = −9.0 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C30H29BNaS⁺]: 455.1981, [M⁺]: 455.1973.

IR (neat, ATR): ṽ/cm⁻¹ = 3056, 2956, 1584, 1429, 1293, 1256, 1183, 1024, 873, 741.

M.p.: 226–228 °C.

10-((4-Mesityloxy)-4-phenyl)-9-sulfonium-10-boratriptycene-ate Complex 2t

According to GP2 with the following quantities of mesityl-phenyl ether[13] (815 mg, 3.8 mmol, 30 equiv). Product obtained as inseparable mixture of two regioisomers (m:p 01:99). Yield: 65%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (p-isomer) 7.95 (d, J = 8.4 Hz, 2H), 7.85 (d, J = 6.8 Hz, 3H), 7.76 (dd, J = 7.6, 0.7 Hz, 3H), 7.23 (td, J = 7.3, 1.1 Hz, 3H), 7.06 (td, J =7.5, 1.4 Hz, 3H), 6.99 (d, J = 8.6 Hz, 2H), 6.97 (s, 2H), 2.35 (s, 3H), 2.28 (s, 6H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 163.3 (CB), 155.8 (Cq), 149.7 (Cq), 136.7 (CH), 134.4 (Cq), 134.2 (CH), 134.0 (Cq), 131.6 (Cq), 130.1 (CH), 129.6 (CH), 127.7 (CH), 124.1 (CH), 114.1 (CH), 21.0 (CH₃), 16.8 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.4 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C33H27BONaS⁺]: 505.1773, [M⁺]: 505.1762.

IR (neat, ATR): ṽ/cm⁻¹ = 3043, 2929, 1584, 1484, 1429, 1297, 1215, 1165, 1010, 887, 832, 741.

M.p.: 203 °C (dec).

10-(5-(2,3-Dimethylchlorophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2u

According to GP1 with the following quantities of 2,3-dimethylchlorobenzene (492 μL, 3.8 mmol, 30 equiv).

Yield: 65%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 7.93 (s, ¹H), 7.84 (d, J = 7.2 Hz, 3H), 7.76 (dd, J = 7.7, 0.8 Hz, 3H), 7.74 (s, ¹H), 7.25 (td, J = 7.4, 1.2 Hz, 3H), 7.07 (td, J = 7.5, 1.4 Hz, 3H), 2.47 (s, 3H), 2.45 (s, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 137.3 (Cq), 135.8 (CH), 134.4 (Cq), 134.1 (CH), 133.7 (CH), 130.4 (Cq), 130.3 (CH), 127.8 (CH), 124.3 (CH), 21.4 (CH₃), 16.3 (CH₃).

The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.6 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C₂₆H₂₀BNaSCl⁺]: 433.0965, [M⁺]: 433.0958.

IR (neat, ATR): ṽ/cm⁻¹ = 3043, 1534, 1475, 1429, 1293, 1256, 1215, 1138, 1006, 969, 892, 801, 750.

M.p.: >300 °C.

10-(4-(1-Chloro-2,6-dimethylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2v

According to GP1 with the following quantities of 2,6-dimethylchlorobenzene (510 μL, 3.8 mmol, 30 equiv). [S1].

Yield: 57%.

The ¹H, ¹³C, and ¹¹B NMR data are identical to that previously reported.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = = 7.84 (d, J = 7.4 Hz, 3H), 7.81 (s, 2H), 7.78 (d, J = 7.7 Hz, 3H), 7.26 (t, J = 7.4 Hz, 3H), 7.08 (t, J = 7.5 Hz, 3H), 2.54 (s, 6H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = = 162.7, 136.0, 134.8 (Cq), 134.4 (Cq), 134.2, 131.5 (Cq), 130.3, 127.8, 124.3, 21.2 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.6 (s).

10-(4-(2,6-Dimethylbromophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2w

According to GP1 with the following quantities of 2,6-dimethylbromobenzene (512 μL, 3.8 mmol, 30 equiv).

Yield: 57%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹ H NMR (500 MHz, CDCl₃): δ (ppm) = 7.85 (d, J = 7.3 Hz, 3H), 7.81 (s, 2H), 7.78 (dd, J = 7.7, 1.0 Hz, 3H), 7.26 (td, J = 7.6, 1.0 Hz, 3H), 7.08 (td, J = 7.4, 1.3 Hz, 3H), 2.58 (s, 6H).

¹³ C NMR (126 MHz, CDCl₃): δ (ppm) = 162.7 (CB), 136.8 (Cq), 135.9 (CH), 134.4 (Cq), 134.1 (CH), 130.3 (CH), 127.8 (CH), 124.5 (Cq), 124.3 (CH), 24.4 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.5 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C26H20BNaS⁷⁹Br⁺]: 477.0460, [M⁺]: 477.0458.

IR (neat, ATR): ṽ/cm⁻¹ = 3052, 1439, 1375, 1297, 1252, 1170, 1129, 1015, 955, 787, 750.

M.p.: >300 °C.

10-(4-Fluorophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2x

According to GP1 with the following quantities of fluorobenzene (966 μL, 10 mmol, 80 equiv). [S1] Product obtained as inseparable mixture of two regioisomers (o:p 10:90). Yield: 64%. The ¹H, ¹³C, and ¹¹B NMR data are identical to that previously reported.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.06–8.00 (m, 2H), 7.80 (d, J = 7.4 Hz, 3H), 7.77 (dd, J = 7.6, 0.6 Hz, 3H), 7.27–7.22 (m, 5H), 7.07 (dt, J = 7.5, 1.4 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 161.4 (d, J = 242.2 Hz, Cq), 136.9 (6.2 Hz, CH), 134.4 (Cq), 134.0 (CH), 130.3 (CH), 127.8 (CH), 124.3 (CH), 114.3 (d, J = 18.1 Hz, CH). The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.5 (s, p-isomer), −10.0 (s, o-isomer).

¹⁹ F NMR (483 MHz, CDCl₃): δ (ppm) = −115.0 (s, o-isomer), −119.2 (s, p-isomer).

10-(4-Chlorophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2y

According to GP1 with the following quantities of chlorobenzene (1.04 mL, 10 mmol, 80 equiv). Product obtained as inseparable mixture of two regioisomers (m:p 20:80). Yield: 66% The ¹H, ¹³C, and ¹¹B NMR data are identical to that previously reported.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (m-isomer) 8.09 (s, ¹H), 7.96 (d, J = 7.5 Hz, ¹H), 7.83–7.76 (m, 6H), 7.49 (t, J = 7.7 Hz, ¹H), 7.38 (d, J = 7.8 Hz, ¹H), 7.27–7.22 (m, 3H), 7.08 (t, J = 7.5 Hz, 3H). (p-isomer) 8.03 (d, J = 7.5 Hz, 2H), 7.83–7.76 (m, 6H), 7.53 (dd, J = 8.1, 1.3 Hz, 2H), 7.27–7.22 (m, 3H), 7.08 (t, J = 7.5 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 137.1, 134.5, 134.0, 130.3, 127.8, 127.7, 124.4, 124.3. The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.5.

10-(4-Bromophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2z

According to GP1 with the following quantities of bromobenzene (1.07 mL, 10 mmol, 80 equiv). [S1] Product obtained as inseparable mixture of two regioisomers (m:p 23:77). Yield: 49%. The ¹H, ¹³C, and ¹¹B NMR data are identical to that previously reported.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (m-isomer) 8.24 (s, ¹H), 8.11–7.98 (m, ¹H), 7.82–7.76 (m, 6H), 7.53 (ddd, J = 7.9, 2.1, 1.1 Hz, ¹H), 7.42 (t, J = 7.6 Hz, ¹H), 7.28–7.24 (m, 3H), 7.08 (t, J = 7.5 Hz, 3H). (p-isomer) 7.96 (d, J = 7.8 Hz, 2H), 7.82–7.76 (m, 6H), 7.67 (d, J = 8.3 Hz, 2H), 7.24 (td, J = 7.4, 1.2 Hz, 3H), 7.08 (td, J = 7.5, 1.5 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 137.6, 134.4, 134.0, 130.7, 130.3, 127.8, 124.4.

The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.4.

10-(4-Iodophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2aa

According to GP1 with the following quantities of iodobenzene (1.16 mL, 10 mmol, 80 equiv). [S1] Product obtained as inseparable mixture of two regioisomers (m:p 33:67). Yield: 47%. The ¹H, ¹³C, and ¹¹B NMR data are identical to that previously reported.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (m-isomer) 8.44 (s, ¹H), 8.03 (d, J = 7.4 Hz, ¹H), 7.80–7.76 (m, 6H), 7.73 (ddd, J = 7.8, 1.8, 1.1 Hz, ¹H), 7.30 (t, J = 7.6 Hz, ¹H), 7.26 (t, J = 7.4 Hz, 3H), 7.08 (t, J = 7.5 Hz, 3H). (p-isomer) 7.87 (d, J = 8.3 Hz, 2H), 7.83 (d, J = 8.1 Hz, 2H), 7.80–7.76 (m, 6H), 7.24 (td, J = 7.4, 1.2 Hz, 3H), 7.08 (td, J = 7.5, 1.4 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.6, 144.3, 137.9, 136.6, 134.7, 134.4 (Cq), 134.1 (Cq), 134.0, 133.9, 133.9, 130.4, 130.3, 127.9, 124.4, 124.3, 91.0.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.5 (s), −9.7 (s).

10-(3-Bromo-4-methylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2ab

According to GP2 with the following quantities of 2-bromotoluene (1.2 mL, 10 mmol, 80 equiv). Product obtained as inseparable mixture of two regioisomers (m:p 50:50) Yield: 65%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = (3-bromo isomer) 8.27 (s, ¹H), 7.82 (dd, J = 7.1, 1.9 Hz, 3H), 7.78 (d, J = 7.7 Hz, 3H), 7.76–7.73 (m, ¹H), 7.43 (d, J = 7.5 Hz, ¹H), 7.28–7.23 (m, 3H), 7.08 (t, J = 7.5 Hz, 3H), 2.56 (s, 3H). (4-bromo isomer) 7.98 (s, ¹H), 7.90 (d, J = 7.3 Hz, ¹H), 7.82 (dd, J = 7.1, 1.9 Hz, 3H), 7.78 (d, J = 7.7 Hz, 3H), 7.71 (d, J = 8.0 Hz, ¹H), 7.28–7.23 (m, 3H), 7.08 (t, J = 7.5 Hz, 3H), 2.55 (s, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.5 (CB), 139.1 (CH), 138.4 (CH), 135.0 (CH), 134.8 (CH), 134.3 (Cq), 134.3 (Cq), 134.1 (CH), 134.0 (CH), 133.8 (Cq), 131.5 (CH), 130.2 (CH), 130.3 (CH), 130.3 (CH), 127.8 (CH), 124.3 (CH), 121.7 (CH), 23.4 (CH₃), 22.9 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = (4-bromo isomer) −9.5 (s) (3-bromo isomer) −9.7 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C₂₅H₁₈BS⁷⁹Br⁺]: 463.0303, [M⁺]: 463.0305.

IR (neat, ATR): ṽ/cm⁻¹ = 3043, 2961, 2929, 1639, 1589, 1511, 1466, 1425, 1265, 1179, 1092, 983, 878, 760.

M.p.: 252–253 °C.

10-(3-(1-Bromo-3-methylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2ac

According to GP1 with the following quantities of 3-bromotoluene (777 μL, 64 mmol, 50 equiv).

Yield: 23%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.00 (s, ¹H), 7.83–7.78 (m, 4H), 7.77 (dd, J = 7.6, 0.8 Hz, 3H), 7.36 (s, ¹H), 7.26 (td, J = 7.4, 1.2 Hz, 3H), 7.08 (td, J = 7.5, 1.4 Hz, 3H), 2.46 (s, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 135.2 (CH), 135.0 (CH), 134.4 (CH), 134.1 (CH), 130.4 (CH), 128.6 (CH), 127.8 (CH), 124.4 (CH), 21.8 (CH₃).

The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.6 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C25H18BNaS⁷⁹Br⁺]: 463.0303, [M⁺]: 463.0290.

IR (neat, ATR): ṽ/cm⁻¹ = 3038, 1584, 1553, 1425, 1288, 1261, 1234, 1156, 960, 851, 810, 755.

M.p.: >300 °C.

10-(3-(o-Difluorophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2ad

According to GP1 with the following quantities of o-difluorobenzene (1.12 mL, 10 mmol, 80 equiv).

Yield: 22%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 7.87–7.81 (m, ¹H), 7.80–8.71 (m, 7H), 7.36–7.28 (m, ¹H), 7.26 (td, J = 7.3, 1.2 Hz, 3H), 7.09 (td, J = 7.5, 1.4 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.3 (CB), 134.3 (Cq), 133.8 (CH), 131.3 (CH), 130.4 (CH), 127.9 (CH), 124.4 (CH), 123.5 (d, J = 13.6 Hz, CF), 116.3 (d, J = 13.3 Hz, CF).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.7 (s).

¹⁹ F NMR (483 MHz, CDCl₃): δ (ppm) = −141.1 (s), −144.6 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C₂₄H₁₅BNaSF₂ ⁺]: 407.0853, [M⁺]: 407.0849.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 1603, 1502, 1429, 1384, 1265, 1151, 1120, 1019, 951, 805, 746.

M.p.: ~250 °C (dec).

10-(3-(4-Fluorobromophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2ae

According to GP1 with the following quantities of 2-fluoro-bromobenzene (1.12 mL, 10 mmol, 80 equiv). Yield: 26%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.24 (d, J = 7.3 Hz, ¹H), 7.93 (s, ¹H), 7.78 (d, J = 7.7 Hz, 3H), 7.75 (d, J = 7.3 Hz, 3H), 7.33–7.28 (m, ¹H), 7.26 (td, J = 7.3, 1.1 Hz, 3H), 7.09 (td, J = 7.4, 1.2 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 140.0 (CH), 136.0 (d, J = 6.1 Hz, CF), 134.3 (Cq), 133.8 (CH), 130.4 (CH), 127.9 (CH), 124.5 (CH).

The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.5 (s).

¹⁹ F NMR (483 MHz, CDCl₃): δ (ppm) = (o-isomer) −110.6, (m-isomer) −114.2, (p-isomer) −113.6.

HRMS (MALDI ⁺ ) (m/z): calcd for [C24H15BNaSBrF⁺]: 467.0053, [M⁺]: 467.0060.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 1571, 1480, 1429, 1297, 1261, 1234, 1183, 1047, 919, 801, 750.

M.p.: 265–267 °C.

10-(5-(1,2-Dibromophenyl)-9-sulfonium-10-boratriptycene-ate Complex 2af

According to GP1 with the following quantities of o-dibromobenzene (773 μL, 64 mmol, 50 equiv).

Yield: 18%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.34 (s, ¹H), 7.84 (d, J = 7.7 Hz, ¹H), 7.79–773 (m, 7H), 7.27 (td, J = 7.4, 1.1 Hz, 3H), 7.09 (td, J = 7.5, 1.3 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 140.5 (CH), 136.0 (CH), 134.2 (Cq), 133.7 (CH), 132.9 (Cq), 130.4 (CH), 127.9 (CH), 124.4 (CH).

The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.8 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C24H15BNaS⁷⁹Br⁺]: 526.9252, [M⁺]: 526.9236.

IR (neat, ATR): ṽ/cm⁻¹ = 3052, 2920, 2851, 1448, 1261, 1188, 1115, 1010, 905, 760.

M.p.: 257–259 °C.

10-(5-(1,2-Difluoro-3-methylphenyl))-9-sulfonium-10-boratriptycene-ate Complex 2ag

According to GP1 with the following quantities of o-difluorobenzene (1.2 mL, 10 mmol, 80 equiv). Yield: 21%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 7.80–7.75 (m, 6H), 7.69–7.58 (m, 2H), 7.26 (td, J = 6.9, 1.0 Hz, 3H), 7.08 (td, J = 7.5, 1.4 Hz, 3H), 2.45 (d, J = 1.9 Hz, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.5 (CB), 134.3 (Cq), 134.1, 133.9 (CH), 132.9, 130.3 (CH), 127.9 (CH), 127.7, 124.4 (CH), 124.3, 120.8 (d, J = 13.7 Hz, CF), 15.0 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = (5-isomer) −9.7 (s), (6-isomer) −10.0 (s).

¹⁹ F NMR (483 MHz, CDCl₃): δ (ppm) = (5-isomer) −142.2 (dd, J = 20.7, 12.2 Hz, 1F), −149.1 (dt, J = 15.9, 7.4 Hz, 1F), (6-isomer) −123.6 (d, J = 21.8 Hz, ¹H), −144.5 (d, J = 22.0 Hz, ¹H).

HRMS (MALDI ⁺ ) (m/z): calcd for [C25H17BNaSF2+]: 421.1010, [M⁺]: 421.1006.

IR (neat, ATR): ṽ/cm⁻¹ = 3047, 1603, 1507, 1420, 1384, 1302, 1261, 1156, 1033, 969, 755.

M.p.: 244–250 °C (dec).

10-(5-(1-Bromo-2chloro-3-methylphenyl)-9-sulfonium-10-boratriptycene-ate Complex 2ah

According to GP1 with the following quantities of 1-bromo-2-chloro-3-methylbenzene (1.32 g, 64 mmol, 50 equiv).

Yield: 26%.

TLC: R _f = 0.9 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.18 (s, ¹H), 7.86 (s, ¹H), 7.78 (dd, J = 7.6, 1.0 Hz, 6H), 7.27 (td, J = 7.4, 1.1 Hz, 3H), 7.09 (td, J = 7.5, 1.3 Hz, 3H), 2.57 (s, 3H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 162.2 (CB), 138.1 (CH), 137.2 (CH), 137.1 (Cq), 134.3 (Cq), 133.8 (CH), 130.5 (Cq), 130.4 (CH), 127.9 (CH), 124.5 (CH), 22.1 (CH₃).

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = −9.8 (s).

HRMS (MALDI ⁺ ) (m/z): calcd for [C25H17BNaSCl⁷⁹Br⁺]: 496.9914, [M⁺]: 496.9901.

IR (neat, ATR): ṽ/cm⁻¹ = 3043, 1530, 1434, 1302, 1265, 1197, 1129, 1047, 965, 896, 846, 746.

M.p.: >300 °C.

10-(N,N,3,5-Tetramethylaniline)-9-sulfonium-10-boratriptycene Lewis Adduct Tetrakis(pentafluorophenyl)borate 4

Under glovebox conditions in a Schlenk tube, HNTf2 (40 mg, 0.14 mmol, 1.1 equiv) was added to a suspension of 10-mesityl-9-sulfonium-10-boratritpyceneate complex 1 (50 mg, 0.13 mmol, 1.0 equiv) in 1,2,3,4-tetrafluorobenzene (3.0 mL). The reaction was stirred for 5 min then NaB(C6F5)4 (139 mg, 0.19 mmol, 1.5 equiv) and stirred for a further 5 min. TMA (105 μL, 0.64 mmol, 5.0 equiv). The Schlenk tube was then sealed with a glass stopper, stirred, and warmed in an oil bath at 60 °C. After 16 h, the volatiles were removed, and the crude was purified via flash chromatography (50:50 n-hexane/CH₂Cl₂) affording pure 10-(N,N,3,5-tetramethylaniline)-9-sulfonium-10-boratriptycene Lewis adduct tetrakis(pentafluorophenyl) borate (82 mg, 0.074 mmol, 58%).

Yield: 58%.

TLC: R _f = 0.3 (50:50 n-hexane/CH₂Cl₂).

¹H NMR (500 MHz, CDCl₃): δ (ppm) = 8.05 (d, J = 7.6 Hz, ¹H), 7.97 (d, J = 7.7 Hz, ¹H), 7.94–7.91 (m, 2H), 7.53–7.45 (m, 3H), 7.33–7.25 (m, 7H), 7.08 (s, 3H), 4.21–4.17 (m, 6H), 2.32–2.03 (br, 6H).

¹³C NMR (126 MHz, CDCl₃): δ (ppm) = 150.8, (Cq), 149.3 (Cq), 147.4 (Cq), 137.3 (CH), 135.4 (CH), 134.8 (CH), 134.7 (CH), 133.4 (CH), 133.1 (CH), 132.7 (Cq), 131.3 (CH), 131.2 (CH), 130.6 (CH), 130.6 (CH), 130.1 (CH), 129.2 (CH), 129.1 (CH), 126.7 (CH), 126.6 (CH), 126.5 (CH), 57.8 (CH₃), 57.7 (CH₃), 21.4 (CH₃). The carbon atoms directly attached to the boron atom on the triptycene core were not detected, likely due to quadrupolar relaxation.

¹¹B NMR (160 MHz, CDCl₃): δ (ppm) = 1.8 (br).

¹⁹ F NMR (483 MHz, CDCl₃): δ (ppm) = −132.4 (d, J = 10.1 Hz, 8F), −162.9 (t, J = 20.5 Hz, 4F), −166.6 (t, J = 18.1 Hz, 8F).

HRMS (MALDI ⁺ ) (m/z): calcd for [C28H27BNNaS⁺]: 420.1957, [M⁺]: 420.1946.

IR (neat, ATR): ṽ/cm⁻¹ = 2951, 2865, 1648, 1511, 1452, 1370, 1275, 1079, 978, 878, 750.

M.p.: 81–82 °C.

• References

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