Synthesis of Spiro[2.2]pentanes and Spiro[2.3]hexanes Employing the Me<sub>3</sub>
Al/CH<sub>2</sub>
I<sub>2</sub>
Reagent
作者:Ilfir R. Ramazanov、Rita N. Kadikova、Tat'yana P. Zosim、Usein M. Dzhemilev、Armin de Meijere
DOI:10.1002/ejoc.201700991
日期:2017.12.22
Substituted alkylidenecyclopropanes reacted with 5 equivalents each of Me3Al and CH2I2 at room temperature in hexane to give 1-mono- and 1,1-disubstituted spiro[2.2]pentanes in high yields. Surprisingly, the same reaction with substituted alkylidenecyclopropanes in CH2Cl2 afforded exclusively 1,1-disubstituted spiro[2.3]hexanes. The transformation of 1,1-diphenylspiro[2.2]pentane into 1,1-diphenylspiro[2