8-endo cyclization of (alkoxycarbonyl) methyl radicals: Radical ways for preparation of eight-membered-ring lactones

E Lee, CH Yoon, TH Lee, SY Kim, TJ Ha…

Index: Lee, Eun; Yoon, Cheol Hwan; Lee, Tae Hee; Kim, Sun Young; Ha, Tae Joon; Sung, Yong-Suk; Park, Sang-Hyun; Lee, Sangyoub Journal of the American Chemical Society, 1998 , vol. 120, # 30 p. 7469 - 7478

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Citation Number: 51

Abstract

Cyclization of (alkoxycarbonyl) methyl radicals generated from bromoacetates proceeds in the 8-endo mode to generate heptanolactones. Three distinct types of 8-endo/5-exo tandem radical cyclizations produce different bicyclic heptanolactones. In certain cases, intramolecular free-radical attack on the heptanolactone carbonyl group initiates further skeletal rearrangement. Ab initio calculations indicate that the preference of the 8-endo ...