Chemoselective, Regioselective, and <i>E</i>/<i>Z</i>-Diastereoselective Synthesis of 2-Alkylidenetetrahydrofurans by Sequential Reactions of Ambident Dianions and Monoanions
作者:Peter Langer、Esen Bellur
DOI:10.1021/jo034966f
日期:2003.12.1
A number of novel beta-ketoesters were prepared by regioselective alkylation reactions of simple beta-ketoester dianions. The cyclization of the dianions of these 1,3-dicarbonyl derivatives with 1-bromo-2-chloroethane afforded a variety of 2-alkylidenetetrahydrofurans with very good regioselectivity and E/Z-diastereoselectivity. These products were deprotonated to give novel ambident carbanions. The