Total synthesis of (.+-.)-africanol and (.+-.)-isoafricanol
作者:Weiming Fan、James B. White
DOI:10.1021/jo00065a018
日期:1993.6
A six-step synthesis of the sesquiterpenes africanol and isoafricanol from 3,5,5-trimethylcyclohex-2-en-1-one is reported. The anionic oxy-Cope rearrangement is used to prepare substituted 5-cyclodecenones functionalized with an allylstannane moiety, which, upon cyclization with the ketone, lead to hydroazulene derivatives. The stereochemistry in the transannular cyclization can be controlled through the choice of reaction conditions both with respect to the ring fusion itself and with respect to a preexisting chiral center. Cyclopropanation of the alkene that is generated following cyclization completes the synthesis of both compounds.