Compared Behaviors of trans- and cis-α,β-Epoxy-γ,δ-vinyl-silanes Towards Nucleophiles and Bases: High Regioselective Ring Opening and Deprotonation

Abstract

This work describes the regioselective nucleophilic ring opening and the deprotonation of α,β-epoxy-γ,δ-vinyl-silanes with nitrogen, sulfur and carbon nucleophiles. In an original way, our results point out the α,β-epoxy-silane-like or vinyloxirane-like behavior of α,β-epoxy-γ,δ-vinyl-silanes according to their configuration and to the type of the nucleophile. Furthermore we report an easy stereoselective access to α-alkylated-α"-silylated-β,γ-unsaturated-ketones.

α,β-epoxy-γ,δ-vinyl-silanes - ring opening of oxiranes - regioselectivity.

References

<A NAME="RG01502ST-1A">1a</A> Le Bideau F. Aubert C. Malacria M. Tetrahedron: Asymmetry  1995,  6:  697 

<A NAME="RG01502ST-1B">1b</A> Gilloir F. Malacria M. Tetrahedron Lett.  1992,  33:  3859 

<A NAME="RG01502ST-2">2</A> Courillon C. Le Fol R. Vandendris E. Malacria M. Tetrahedron Lett.  1997,  38:  5493 

<A NAME="RG01502ST-3">3</A> Le Bideau F. Gilloir F. Nilsson Y. Aubert C. Malacria M. Tetrahedron Lett.  1995,  36:  1641 

<A NAME="RG01502ST-4">4</A> Le Bideau F. Gilloir F. Nilsson Y. Aubert C. Malacria M. Tetrahedron  1996,  52:  7487 

<A NAME="RG01502ST-5">5</A> Marion F. Le Fol R. Courillon C. Malacria M. Synlett  2001,  138 

<A NAME="RG01502ST-6">6</A> Kawai T. Isobe M. Peters SC. Aust. J. Chem.  1995,  48:  115 

<A NAME="RG01502ST-7">7</A> Nobuki O. Organomet. News  2000,  3:  84 

<A NAME="RG01502ST-8">8</A> Jacobsen EN. Wu MH. In Comprehensive Asymmetric Catalysis I-III   Jacobsen EN. Pfaltz A. Yamamoto H. Springer; New York: 1999.  Chap. 35.

<A NAME="RG01502ST-9">9</A> Garcia R. Martinez M. Aracil J. Chem. Eng. Technol.  1999,  22:  987 

<A NAME="RG01502ST-10">10</A> Zamojski A. Chemtracts  1998,  11:  287 

<A NAME="RG01502ST-11">11</A> Behrens CJ. Sharpless KB. J. Org. Chem.  1985,  50:  5696 

<A NAME="RG01502ST-12">12</A> Colvin EW. Chem. Org. Silicon Compd.  1998,  2:  1667 

<A NAME="RG01502ST-13">13</A> Davis AP. Hughes GJ. Lowndes P. Robbins CM. Thomas EJ. Whitham GH. J. Chem. Soc., Perkin
Trans. 1  1981,  7:  1934 

<A NAME="RG01502ST-14">14</A> Hudrlik PF. Hudrlik AM. Adv. Silicon Chem.  1993,  2:  1 

<A NAME="RG01502ST-15">15</A> Chauret DC. Chong JM. Tetrahedron Lett.  1993,  34:  3695 

<A NAME="RG01502ST-16">16</A> Masnyk M. Wicha J. Chem. Ber.  1994,  127:  677 

<A NAME="RG01502ST-17">17</A> Bassindale AR. Soobramanien M.-C. Taylor PG. Bull. Soc. Chim. Fr.  1995,  132:  604 

<A NAME="RG01502ST-18">18</A> Adam W. Prein M. Richter MJ. Tetrahedron  1996,  52:  1231 

<A NAME="RG01502ST-19">19</A> Marshall JA. Chem. Rev.  1989,  89:  1503 

<A NAME="RG01502ST-20">20</A> Ittah Y. Sasson Y. Tsaroom S. Blum J. J. Org. Chem.  1978,  43:  4271 

<A NAME="RG01502ST-21">21</A> Coldham I. Collis AJ. Mould RJ. Electron. Conf. Heterocycl. Chem., [Proc.]   1997.  Rzepa HS. Snyder JP. Leach C. Royal Society of Chemistry; Cambridge: 1997. 

<A NAME="RG01502ST-22A">22a</A> Tenaglia A. Waegell B. Tetrahedron Lett.  1988,  29:  4851 

<A NAME="RG01502ST-22B">22b</A> Chini M. Crotti P. Macchia F. Tetrahedron Lett.  1990,  31:  4661 

<A NAME="RG01502ST-22C">22c</A> Hayashi M. Kohmura K. Oguni N. Synlett  1991,  774 

<A NAME="RG01502ST-22D">22d</A> Canas M. Poch M. Verdaguer X. Moyano A. Pericas MA. Riera A. Tetrahedron Lett.  1991,  32:  6931 

<A NAME="RG01502ST-23A">23a</A> Fristad WE. Bailey TR. Paquette LA. Gleiter R. Böhm MC. J. Am.Chem. Soc.  1979,  101:  4420 

<A NAME="RG01502ST-23B">23b</A> Tomoda S. Matsumoto Y. Takeuchi Y. Nomura Y. Chem. Lett.  1986,  7:  1193 

<A NAME="RG01502ST-23C">23c</A> Hudrlik PF. Hudrlik AM. Kulkarni AK. Tetrahedron Lett.  1985,  26:  139 

<A NAME="RG01502ST-23D">23d</A> Chakraborty TK. Reddy GV. Tetrahedron Lett.  1990,  31:  1335 

<A NAME="RG01502ST-24A">24a</A> Eisch JJ. Galle JE. J. Am. Chem. Soc.  1976,  98:  4646 

<A NAME="RG01502ST-24B">24b</A> Eisch JJ. Galle JE. J. Organomet. Chem.  1988,  341:  293 

<A NAME="RG01502ST-24C">24c</A> Molander GA. Mautner K. J. Org. Chem.  1989,  54:  4042 

<A NAME="RG01502ST-25">25</A> Eisch JJ. Galle JE. J. Org. Chem.  1990,  55:  4835 

<A NAME="RG01502ST-26">26</A> Molander GA. Mautner K. Pure Appl. Chem.  1990,  62:  707 

<A NAME="RG01502ST-27">27</A>

Preparation of 7a: To a solution of the trans-silylated vinyloxirane 1a (100 mg, 0.54 mmol, 1 equiv) in pentane (10 mL), under argon, was added dropwise, at -30 °C, to a solution of tert-butyllithium in pentane (0.72 mL of a 1.5 M, 1.08 mmol, 2 equiv). The reaction was monitored by TLC and after completion of the reaction it was quenched at this temperature, with a 1:1 solution of propionic acid:diethyl ether. The reaction mixture was then allowed to warm to room temperature and treated with an excess of a saturated sodium hydrogenocarbonate solution. The aqueous layer was then extracted with ethyl acetate. The combined organic layers were washed with brine and dried over anhydrous sodium sulfate. Flash chromatography on silica gel (petoleum ether/diethyl ether, 98:2) gave 116 mg (89%) of the desired product as a 2:1 mixture of two diastereomers E/Z.
E diastereomer: ¹H NMR (200 MHz, C₆D₆): δ = 5.59 (1 H, dd, J = 15.25, 5.40 Hz), 5.44 (1 H, dt, J = 15.25, 6.90 Hz), 3.93 (1 H, d, J = 5.90 Hz), 1.90 (2 H, d, J = 6.40 Hz), 1.03 (9 H, s), 0.89 (9 H, s), 0.09 (3H, s), -0.02 (3H, s).
¹³C NMR (50 MHz, C₆D₆): δ = 136.33, 124.80, 67.77, 48.42, 30.41 (3 C), 28.23 (3 C), 19.44, 18.16, -6.18, -7.82.
Z diastereomer: ¹H NMR (200 MHz, C₆D₆): δ = 5.64 (1 H, dd, J = 10.82, 10.34 Hz), 5.34 (1 H, m), 4.40 (1 H, d, J = 10.37 Hz), 2.01 (1 H, d, J = 9.20 Hz), 1.80 (1 H, dd, J = 5.62, 1.70 Hz) 1.05 (9 H, s), 0.86 (9 H, s), 0.13 (3 H, s), 0.00 (3 H, s).
¹³C NMR (50 MHz, C₆D₆): δ = 133.62, 125.95, 62.38, 41.89, 29.50 (3 C), 27.46 (3 C), 19.60, 17.49, -7.07, -8.26.

<A NAME="RG01502ST-28">28</A>

Preparation of 10 (typical procedure for lithiation of the cis-epoxide): To a cold solution (-116 °C) of the cis-silylated vinyloxirane 1b (200 mg, 1.08 mmol, 1 equiv) and TMEDA (0.25 mL, 1.63 mmol, 1.5 equiv) in diethyl ether (10 mL) was added dropwise a solution of sec-butyllithium in cyclohexane (1.67 mL of a 1.3 M, 2.17 mmol, 2 equiv). The reaction mixture was stirred under argon at this temperature until the bright yellow lithiated anion precipitated (ca 30-45 minutes). Methyliodide (0.68 mL, 10.85 mmol, 10 equiv) was then quickly added to the solution and after 10 minutes at -116 °C, the mixture was allowed to warm to room temperature. The organic layer was washed with a saturated ammonium chloride solution, and the aqueous phase was extracted with diethyl ether. The combined organic layers were washed with brine and dried over anhydrous sodium sulfate. Evaporation under reduced pressure afforded the crude product that was purified by flash chromatography on silica gel (petroleum ether/diethyl ether, 99:1). The desired product was obtained in 89% yield.
¹H NMR (200 MHz, C₆D₆): δ = 5.74 (1 H, ddd, J = 17.70, 10.32, 8.36 Hz), 5.25 (1 H, dd, J = 17.22, 1.48 Hz), 5.04 (1 H, dd, J = 10.82, 0.98 Hz), 3.01 (1 H, d, J = 8.38 Hz), 1.18 (3 H, s), 0.90 (9 H, s), 0.05 (3 H, s), 0.00 (3 H, s).
¹³C NMR (50 MHz, C₆D₆): δ = 138.09, 119.95, 67.01, 56.64, 28.53 (3 C), 25.87, 18.28, -3.85, -4.21.

<A NAME="RG01502ST-29">29</A>

Rearrangement of 10 with palladium(0): Triphenylphosphite (26 µL, 0.10 mmol, 0.2 equiv) was added via a syringe to a stirred solution of palladium diacetate (6 mg, 0.03 mmol, 0.05 equiv) in freshly distilled THF (1 mL). After 10 minutes at room temperature, a solution of vinylepoxysilane 10 (100 mg, 0.5 mmol, 1 equiv) in THF (2 mL) was transferred by cannula into the pale yellow reaction mixture. After completion of the rearrangement (ca 2 h), the crude mixture was filtered through a pad of celite and the organic layer was directly evaporated under reduced pressure. After purification by flash chromatography on silica gel, the ketone 14 was obtained in 82% yield.
¹H NMR (200 MHz, CDCl₃): δ = 6.06 (1 H, ddd, J = 17.22, 10.82, 10.32 Hz), 4.93 (1 H, dd, J = 10.34, 1.48 Hz), 4.90 (1 H, dd, J = 16.74, 1.48 Hz), 3.41 (1 H, d, J = 10.82 Hz), 2.11 (3 H, s), 0.91 (9 H, s), 0.07 (3H, s), 0.03 (3H, s).
¹³C NMR (50 MHz, C₆D₆): δ = 207.42, 134.36, 113.99, 54.01, 31.30, 26.84 (3 C), 18.38, -6.12, -6.63.