Biomimetic Cyclization of Enamide-Containing Polyenes as a New Route to Azapolycycles
作者:Stephanie E. Sen、Steven L. Roach
DOI:10.1021/jo960924y
日期:1996.1.1
Enamide 4 was studied for its effectiveness as a polyene precursor in biomimeticcyclizations. While most conventional Lewis acids were poor cyclization promoters, FeCl(3).6H(2)O initiated the conversion of 4 into tricycles 6 and 7 in excellent yield. The two isomeric products result from the cyclization of intermediate aldehyde 5 by either a chair or boat B-ring transition state. These results suggest