8-Endo Cyclization of (Alkoxycarbonyl)methyl Radicals: Radical Ways for Preparation of Eight-Membered-Ring Lactones
作者:Eun Lee、Cheol Hwan Yoon、Tae Hee Lee、Sun Young Kim、Tae Joon Ha、Yong-suk Sung、Sang-Hyun Park、Sangyoub Lee
DOI:10.1021/ja980908d
日期:1998.8.1
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, intramolecularfree-radical attack on the heptanolactone carbonyl group initiates further skeletal rearrangement. Ab initio calculations indicate
The prenylation of isopentenyl and 3,3-dimethylallyl derivatives could be achieved effeciently with dimethyl, vinyl carbinol and a variety of acids in nitromethane. Geraniol and isopentenylacetate led to farnesyl derivatives.
Basic elimination of sulfonium salts. Neighbouring group influence on regioselectivity.
作者:B. Badet、M. Julia、J.M. Mallet、C. Schmitz
DOI:10.1016/s0040-4039(00)88333-1
日期:1983.1
A simple preparation of sulfonium salts functionalized by oxygenated groups is reported. The nature and the position of the latter control the regiochemistry of elimination of the sulfonium moiety leading to selective formation of Saytsev or Hofmann olefins.