Irradiation of 4,4-dimethyl-3-[(2-cyclopentenyl)methoxy]-2-cyclohexen-1-one, prepared from 4,4-dimethyl-3-phenylthio-2-cyclohexen-1-one and (2-cyclopentenyl) methanol, gave a tetracyclic intramolecular [2+2]photocycloadduct 7. Treatment of 7 with iodotrimethylsilane followed with tributyltin hydride afforded 3,3,11-trimethylbicyclo[6.3.0]undecane-2,6-dione(12). Methylenation of 12 afforded 6-methylene-3,3,11-trimethylbicyclo[6.3.0] undecan-2-one, the known intermediate to precapnelladiene.
Preparation of (<i>R</i>)-(2-Cyclopentenyl)methanol and the First Total Synthesis of (8<i>R</i>,11<i>R</i>)-Precapnelladiene
作者:Koji Maeda、Yoshinobu Inouye
DOI:10.1246/bcsj.67.2880
日期:1994.10
Enantiometrically pure (R)-(2-cyclopentenyl)methanol (2) was prepared from ethyl 2-oxocyclopentanecarboxylate. Coupling of 2 with 4,4-dimethyl-3-phenylthio-2-cyclohexenone gave an enol ether, which...