Radical Alkylations of Alkyl
Halides and Unactivated C-H Bonds Using Vinyl Triflates

Jin Young Lee; Kyoung-Chan Lim; Xiangjian Meng; Sunggak Kim

doi:10.1055/s-0029-1219960

LETTER

Radical Alkylations of Alkyl Halides and Unactivated C-H Bonds Using Vinyl Triflates

Jin Young Lee^a, Kyoung-Chan Lim^a, Xiangjian Meng^b, Sunggak Kim*^a,b
^a Department of Chemistry, Korea Advanced Institute of Science & Technology, Daejeon 305-701, Korea
^b Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
Fax: +65(6791)1961; e-Mail: sgkim@ntu.edu.sg;

Abstract

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Abstract

Radical alkylations of activated alkyl iodides and bromides were achieved using vinyl triflates in the presence of hexadimethyltin, whereas those of unactivated C-H bonds using vinyl triflates proceeded cleanly under tin-free conditions.

Key words

alkylation - radical reaction - ketone - vinyl triflate

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Referenzen

References and Notes

<A NAME="RU02610ST-1A">1a</A> House HO. Modern Synthetic Reactions Benjamin WA. Menlo Park; CA: 1972. Chap. 9.

<A NAME="RU02610ST-1B">1b</A> Caine D. In Comprehensive Organic Synthesis Trost BM. Fleming I. Pattenden G. Pergamon; Oxford: 1991. Vol. 3. p.1-63

<A NAME="RU02610ST-1C">1c</A> Seebach D. Angew. Chem. Int. Ed. 1988, 27: 1624

<A NAME="RU02610ST-2">2</A> Kim S. In Radicals in Organic Synthesis Vol 2.: Renaud P. Sibi M. Wiley-VCH; Weinheim: 2001. p.1-21

<A NAME="RU02610ST-3A">3a</A> Watanabe Y. Yoneda T. Ueno Y. Toru T. Tetrahedron Lett. 1990, 31: 6669

<A NAME="RU02610ST-3B">3b</A> Miura K. Fujisawa H. Saito D. Hosomi A. Org. Lett. 2001, 3: 2591

<A NAME="RU02610ST-4">4</A> Roepel MG. Tetrahedron Lett. 2002, 43: 1973

<A NAME="RU02610ST-5A">5a</A> Perkins MJ. Roberts BP. J. Chem. Soc., Perkin Trans. 1975, 2: 77

<A NAME="RU02610ST-5B">5b</A> Dang H.-S. Franchi P. Roberts BP. Chem. Commun. 2000, 499

<A NAME="RU02610ST-5C">5c</A> Fielding AJ. Franchi P. Roberts BP. Smits TM. J. Chem. Soc., Perkin Trans. 2002, 2: 155

<A NAME="RU02610ST-6A">6a</A> Kim S. Lim CJ. Song C. Chung W.-j. J. Am. Chem. Soc. 2002, 124: 14306

<A NAME="RU02610ST-6B">6b</A> Kim S. Lim CJ. Angew. Chem. Int. Ed. 2004, 43: 5378

<A NAME="RU02610ST-6C">6c</A> Song H.-J. Lim CJ. Lee S. Kim S. Chem. Commun. 2006, 2893

<A NAME="RU02610ST-7">7</A> Kim S. Lee JY. Synlett 2008, 49

<A NAME="RU02610ST-8A">8a</A> Ritter K. Synthesis 1993, 735

<A NAME="RU02610ST-8B">8b</A> Roth GP. Fuller CE. J. Org. Chem. 1989, 54: 4899

<A NAME="RU02610ST-8C">8c</A> Pridgen LN. Huang GK. Tetrahedron Lett. 1998, 39: 8421

<A NAME="RU02610ST-8D">8d</A> Limmert ME. Roy AH. Hartwig JF. J. Org. Chem. 2005, 70: 9364

<A NAME="RU02610ST-9A">9a</A> Huffman MA. Yasuda N. Synlett 1999, 471

<A NAME="RU02610ST-9B">9b</A> Baxter JM. Steinhubel D. Palucki M. Davies IW. Org. Lett. 2005, 7: 215

<A NAME="RU02610ST-10">10</A> Cui D.-M. Meng Q. Zheng J.-Z. Zhang C. Chem. Commun. 2009, 1577

<A NAME="RU02610ST-11A">11a</A> Wille U. J. Am. Chem. Soc. 2002, 124: 14

<A NAME="RU02610ST-11B">11b</A> Wille U. Org. Lett. 2000, 2: 3485

<A NAME="RU02610ST-12A">12a</A> Kim S. Kim S. Bull. Chem. Soc. Jpn. 2007, 80: 809

<A NAME="RU02610ST-12B">12b</A> Kim S. Kim S. Otsuka N. Ryu I. Angew. Chem. Int. Ed. 2005, 44: 6183

<A NAME="RU02610ST-12C">12c</A> Kim S. Lim CJ. Angew. Chem. Int. Ed. 2002, 41: 3265

For alkynylations, see:

<A NAME="RU02610ST-13A">13a</A> Gong J. Fuchs PL. J. Am. Chem. Soc. 1996, 118: 4486

<A NAME="RU02610ST-13B">13b</A> Gong J. Fuchs PL. Tetrahedron Lett. 1997, 38: 787

For alkenylations, see:

<A NAME="RU02610ST-13C">13c</A> Xiang J. Fuchs PL. J. Am. Chem. Soc. 1996, 118: 11986

<A NAME="RU02610ST-13D">13d</A> Xiang J. Jiang W. Gong J. Fuchs PL. J. Am. Chem. Soc. 1997, 119: 4123

<A NAME="RU02610ST-13E">13e</A> For allylation, see: Xiang J. Evarts J. Rivkin A. Curran DP. Fuchs PL. Tetrahedron Lett. 1998, 39: 4163

<A NAME="RU02610ST-14A">14a</A> Kharasch MS. Brown HC. J. Am. Chem. Soc. 1942, 64: 329

<A NAME="RU02610ST-14B">14b</A> Tabushi I. Hamuro J. Oda R. J. Org. Chem. 1968, 33: 2108

<A NAME="RU02610ST-15A">15a</A> Bentrude WG. Darnall KR. J. Am. Chem. Soc. 1968, 90: 3588

<A NAME="RU02610ST-15B">15b</A> Citterio A. Filippini L. Synthesis 1986, 473

<A NAME="RU02610ST-15C">15c</A> Kim S. Kim N. Chung W.-j. Cho CH. Synlett 2001, 937

<A NAME="RU02610ST-16">16</A> Akindele T. Yamada K.-I. Tomioka K. Acc. Chem. Res. 2009, 42: 345 ; and references cited therein

Typical procedure for radical alkylation of a carbonyl compound: A solution of iodomethyl phenylsulfone (56 mg, 0.2 mmol), vinyl triflate 7 (76 mg, 0.3 mmol), and hexamethylditin (33 mg, 0.1 mmol) in benzene (1 mL; 0.2 M in iodide) was degassed with nitrogen for 10 min, and the solution was then irradiated in a photochemical reactor (300 nm) for 5 h. The solvent was evaporated under reduced pressure and the residue was purified by silica gel column chromatography (EtOAc-hexane, 1:10) to give 1-phenyl-3-(phenylsulfonyl)propan-1-one (38 mg, 69%) as a colorless oil. ^¹H NMR (CDCl₃, 400 MHz): δ = 3.45-3.49 (m, 2 H), 3.52-3.56 (m, 2 H), 7.42-7.46 (m, 2 H), 7.55-7.57 (m, 3 H), 7.63-7.64 (m, 1 H), 7.88-7.94 (m, 4 H); ^¹³C NMR (CDCl₃, 100 MHz): δ = 31.3, 51.0, 127.9 (C2), 128.0 (C2), 128.7 (C2), 129.4 (C2), 133.7, 133.9, 135.8, 139.0, 195.3

Typical procedure for radical alkylation of an unactivated C-H bond: A solution of vinyl triflate 9 (76 mg, 0.3 mmol) and AIBN (5 mg, 0.03 mmol) in THF (1 mL) was degassed with nitrogen for 10 min, and the solution was heated at reflux (80 ˚C) for 9 h under nitrogen. The solvent was evaporated under reduced pressure and the residue was purified by silica gel column chromatography (EtOAc-hexane, 1:50) to give 16 (41 mg, 65%) as a colorless oil. ^¹H NMR (CDCl₃, 400 MHz): δ = 1.33 (t, J = 7.2 Hz, 3 H), 1.48-1.55 (m, 1 H), 1.84-1.92 (m, 2 H), 2.06-2.14 (m, 1 H), 2.94 (dd, J = 16.5, 5.7 Hz, 1 H), 3.10 (dd, J = 16.5, 7.1 Hz, 1 H), 3.67-3.73 (m, 1 H), 3.80-3.85 (m, 1 H), 4.29 (q, J = 7.2 Hz, 2 H), 4.26-4.32 (m, 1 H); ^¹³C NMR (CDCl₃, 100 MHz): δ = 13.9, 25.4, 31.4, 45.1, 62.4, 67.9, 74.3, 160.8, 192.6