Translocation of radical sites by intramolecular 1,5-hydrogen atom transfer

Journal of the American Chemical Society

Volumn 110, Issue 17, 1988, Pages 5900-5902

  Curran, Dennis P ^a   Kim, Dooseop ^a   Liu, Hong Tao ^a   Shen, Wang ^a  

^a UNIVERSITY OF PITTSBURGH   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0001279669     PISSN: 00027863     EISSN: 15205126     Source Type: Journal    
DOI: 10.1021/ja00225a052     Document Type: Article

References (8)

1. Reviews: Curran, D. P. Synthesis 1988, 417, 489. Neumann, W. P. Synthesis 1987, 665. Giese, B. Radicals in Organic Synthesis: Formation of Carbon-Carbon Bonds; Pergamon Press: Oxford, 1986. Ramaiah, M. Tetrahedron 1987, 43, 3541.
2. Hydrogen atom transfer is a fundamental reaction of organic free radicals which is a key step in transformations such as the Kharasch, Barton, and Hofmann-Löffler-Freytag reactions. Remote functionalization by intramolecular H-atom transfer has been extensively studied by Breslow. For a leading reference, see: Breslow, R.; Heyer, D. J. Am. Chem. Soc. 1982, 104, 2045.
3. An example of 1,5-H atom transfer prior to an addition reaction has been reported by Giese. Giese, B.; Dupuis, J.; Hasskerl, T.; Meixner, J. Tetrahedron Lett. 1983, 24, 703. (b) For a Kharasch reaction where cyclization follows H-atom transfer, see: Heiba, E. I.; Dessau, R. M. J. Am. Chem. Soc. 1967, 89, 3772.
4. For some interesting examples where 1,5-hydrogen atom transfer has intervened in reactions conducted by the tin hydride method, see: Beckwith, A. L. J.; O'Shea, D. M.; Gerba, S.; Westwood, S. W. J. Chem. Soc., Chem. Commun. 1987, 666. Choi, J.-K.; Hart, D. J. Tetrahedron 1985, 41, 3959. Bennett, S. M.; Clive. D. L. J. J. Chem. Soc., Chem. Commun. 1986, 878. Chenera, B.; Chuang, C.-P.; Hart, D. J.; Hsu, L.-Y. J. Org. Chem. 1985, 50, 5409.
5. Very recently, an example of this approach has appeared in which an allylic hydrogen is transferred. Lathbury, D. C.; Parsons, P. J.; Pinto, I. J. Chem. Soc., Chem. Commun. 1988, 81.
6. For pertinent mechanistic studies of substituent effects on hydrogen atom abstraction, see: Beckwith, A. L. J.; Brumby, S. J. Chem. Soc., Perkin Trans. 2 1987, 1801. Malatesta, V.; Scaiano, J. C. J. Org. Chem. 1982, 47, 1455. Malatesta, V.; Ingold, K. U. J. Am. Chem. Soc. 1981, 103, 609. Beckwith, A. L. J.; Easton, C. J. J. Am. Chem. Soc. 1981, 103, 615.
7. Stork, G.; Sher, P. M. J. Am. Chem. Soc. 1986, 108, 303.
8. (o-Bromophenyl)dimethylsilyl chloride was prepared by silylation of o-bromophenyllithium. See: Chen, L. S.; Chen, G. J.; Tamborski, C. J. Organomet. Chem. 1980, 193, 283. This procedure was modified as follows: dimethyldichlorosilane was added before n-butyllithium, and the product was isolated by nonaqueous workup (evaporation of the THF, dilution with hexane, filtration and concentration). We thank Drs. Richard Elliott and Thomas Fevig for the preparation of this silyl chloride.