Synthesis, Table of Contents Synthesis 2022; 54(20): 4576-4582DOI: 10.1055/a-1874-4935 paper Aryl Ketone Mediated Light-Driven Naphthylation of C(sp3)–H Bonds Attached to either Oxygen or Nitrogen Substituents Authors Masaya Azami Toshihiro Murafuji Shin Kamijo∗ Recommend Article Abstract Buy Article(opens in new window) All articles of this category(opens in new window) Abstract A light-driven naphthylation was achieved at C(sp3)–H bonds attached to either oxygen or nitrogen substituents using sulfonylnaphthalenes as a naphthalene precursor in the presence of 4-benzoylpyridine at ambient temperature. The present transformation is proposed to proceed through the generation of a carbon radical species via chemoselective cleavage of the heteroatom-substituted C(sp3)–H bond by photoexcited 4-benzoylpyridine, the addition of the derived carbon radical to the electron-deficient sulfonylnaphthalene, and then rearomatization by releasing sulfinyl radical. Key words Key wordsC–H functionalization - naphthylation - photoreaction - aryl ketones - ethers - amides Full Text References References For representative books on functionalization of non-acidic C–H bonds, see: 1a Handbook of C–H Transformations . Dyker G. Wiley-VCH; Weinheim: 2005 1b Handbook of Reagents for Organic Synthesis: Reagents for Direct Functionalization of C–H Bonds. Paquette LA, Fuchs PL. Wiley; Chichester: 2007 1c Alkane C–H Activation by Single-Site Metal Catalysis. Pérez PJ. Springer; Dordrecht: 2012 1d From C–H to C–C Bonds: Cross-Dehydrogenative-Coupling . Li C.-J. Royal Society of Chemistry; Cambridge: 2015 1e C–H Bond Activation in Organic Synthesis 2015 1f Science of Synthesis: Catalytic Transformations via C–H Activation 2. Yu J.-Q. Thieme; Stuttgart: 2016 2 Kamijo S, Kamijo K, Murafuji T. J. Org. Chem. 2017; 82: 2664 3 Kamijo S, Kamijo K, Murafuji T. Synthesis 2019; 51: 3859 For representative reports of light-driven aryl ketone mediated C(sp3)–H functionalizations from other research groups, see: 4a Hoshikawa T, Inoue M. Chem. Sci. 2013; 4: 3118 4b Xia J.-B, Zhu C, Chen C. J. Am. Chem. Soc. 2013; 135: 17494 4c Kee CW, Chin KF, Wong MW, Tan C.-H. Chem. Commun. 2014; 50: 8211 4d Xia J.-B, Zhu C, Chen C. Chem. Commun. 2014; 50: 11701 4e Cantillo D, de Frutos O, Rincón JA, Mateos C, Kappe CO. J. Org. Chem. 2014; 79: 8486 4f Nagatomo M, Yoshioka S, Inoue M. Chem. Asian J. 2015; 10: 120 4g Ota E, Mikame Y, Hirai G, Nishiyama S, Sodeoka M. Synlett 2016; 27: 1128 5a Lipshutz BH, Sengupta S. Org. React. 1992; 41: 135 5b Amano T, Yoshikawa K, Sano T, Ohuchi Y, Shiono M, Ishiguro M, Fujita Y. Synth. Commun. 1986; 16: 499 5c Wakefield BJ. Organomagnesium Methods in Organic Synthesis. Academic; London: 1995 5d Kruse CG, Wijsman A, van der Gen A. J. Org. Chem. 1979; 44: 1847 6a Olah GA, Krishnamurti R, Prakash GK. S. In Comprehensive Organic Synthesis, Vol. 3. Trost BM, Fleming I. Pergamon; Oxford: 1991: 293-339 6b He T, Klare HF. T, Oestreich M. ACS Catal. 2021; 11: 12186 7a Sandrock DL. In Science of Synthesis: Cross Coupling and Heck-Type Reactions 1 . Molander GA. Thieme; Stuttgart: 2013: 323-357 7b Molander GA, Beaumard F. Org. Lett. 2011; 13: 1242 7c Molander GA, Beaumard F, Niethamer TK. J. Org. Chem. 2011; 76: 8126 7d Murai N, Yonaga M, Tanaka K. Org. Lett. 2012; 14: 1278 Other representative examples of the coupling strategies for preparation of alkylated naphthalenes: 8a Gourai SK, Jin M, Hatakeyama T, Nakamura M. Org. Lett. 2012; 14: 1066 8b Silberstein A, Ramgren SD, Garg NK. Org. Lett. 2012; 14: 3796 8c Sun C.-L, Krause H, Fürstner A. Adv. Synth. Catal. 2014; 356: 1281 8d Iwasaki T, Min X, Fukuoka A, Kuniyasu H, Kambe N. Angew. Chem. Int. Ed. 2016; 55: 5550 9a Ueno R, Shirakawa E. Org. Biomol. Chem. 2014; 12: 7469 9b Ueno R, Ikeda Y, Shirakawa E. Eur. J. Org. Chem. 2017; 4188 9c Ikeda Y, Ueno R, Akai Y, Shirakawa E. Chem. Commun. 2018; 54: 10471 9d Aoki K, Yohekura K, Ikeda Y, Ueno R, Shirakawa E. Adv. Synth. Catal. 2020; 362: 2200 Other recent examples for preparation of alkylated naphthalenes: 10a Zhu J, Pérez M, Caputo CB, Stephan DW. Angew. Chem. Int. Ed. 2016; 55: 1417 10b Li H, Breen CP, Seo H, Jamison TF, Fang Y.-Q, Bio MM. Org. Lett. 2018; 20: 1338 10c Yue H, Zhu C, Shen L, Geng Q, Hock KJ, Yuan T, Cavallo L, Rueping M. Chem. Sci. 2019; 10: 4430 10d Mane KD, Mukherjee A, Vanka K, Suryavanshi G. J. Org. Chem. 2019; 84: 2039 For examples of light-driven C(sp3)–H functionalizations utilizing 4-BzPy, see: 11a Kamijo S, Watanabe M, Kamijo K, Tao K, Murafuji T. Synthesis 2016; 48: 115 11b Kamijo S, Takao G, Kamijo K, Hirota M, Tao K, Murafuji T. Angew. Chem. Int. Ed. 2016; 55: 9695 For closely related examples of light-driven aryl ketone mediated C(sp3)–H functionalizations from our group, see: 12a Amaoka Y, Nagatomo M, Watanabe M, Tao K, Kamijo S, Inoue M. Chem. Sci. 2014; 5: 4339 12b Kamijo S, Takao G, Kamijo K, Tsuno T, Ishiguro K, Murafuji T. Org. Lett. 2016; 18: 4912 12c Kamijo S, Kamijo K, Maruoka K, Murafuji T. Org. Lett. 2016; 18: 6516 13 A radical chain mechanism, by hydrogen atom abstraction from THF (1a) with in-situ generated methanesulfinyl radical, seems not to be operating in the present case because the reaction ceased when the light was turned off; see Supporting Information for details and also, see: Wang Y.-T, Shih Y.-L, Wu Y.-K, Ryu I. Adv. Synth. Catal. 2022; 364: 1039 14 We, indeed, confirmed that the reaction of THF (1a) with 4-methoxy-1-(methylsulfonyl)naphthalene (2j) in the presence of 4-BzPy did not provide the expected product 3aj, and the recovery of a significant amount of the naphthalene precursor 2j was observed. 15 The reason for the different reactivities of Ph2CO, 2-BzPy, 3-BzPy, and 4-BzPy is not clear at the moment. 16 For beneficial effect of a base, see: Lipp A, Lahm G, Opatz T. J. Org. Chem. 2016; 81: 4890 17 The addition of K2CO3 might work as an effective scavenger of in-situ formed methanesulfinic acid and assists the regeneration of 4-BzPy. 18 The reactions of three- and four-membered cyclic ethers did not produce the expected alkylated naphthalenes. Furthermore, the naphthylation of tetrahydrothiophene, a sulfur-containing cyclic compound, resulted in a complex mixture of unidentified products and the expected adduct could not be identified. 19 The formation of 1-(tetrahydrofuran-2-yloxy)-2,2,6,6-tetramethylpiperidine (4) [CAS Reg. No. 197246-28-9] was confirmed by comparison with the reported data; see: Pan S, Liu J, Li H, Wang Z, Guo X, Li Z. Org. Lett. 2010; 12: 1932 20 We also measured the kinetic isotope effect (KIE) by treating a mixture of THF (1a) and its fully deuterated analogue 1a-d with the naphthalene precursor 2b under the optimized conditions. The value of the KIE was determined to be 1.6. A relatively small value of the KIE might indicate that the C–H bond cleavage by photoexcited 4-BzPy could be taking place in more concerted fashion, for instance, via electron transfer between photoexcited 4-BzPy and THF followed by proton abstraction. In any case, further investigations are required to clarify the detailed reaction pathway. 21 Singh PP, Gudup S, Ambala S, Singh U, Dadhwal S, Singh B, Sawant SD, Vishwakarma RA. Chem. Commun. 2011; 47: 5852 Supplementary Material Supplementary Material Supporting Information (PDF)
