Tetrahedron

Free radical annulation of dichlorocyclobutanones with sequential ring expansion

P Dowd, W Zhang, SJ Geib

Index: Dowd, Paul; Zhang, Wei; Geib, Steven J. Tetrahedron, 1995 , vol. 51, # 12 p. 3435 - 3454

Full Text: HTML

Citation Number: 20

Abstract

A new synthetic sequence that adds the elements of ketene across the termini of a 1, 5- diene is described. Dichlorocyclobutanone adducts from reaction of dichloroketene with 1, 5- dienes undergo intramolecular free radical annulation. Lewis acid-promoted ring-opening of the cyclized cyclobutanones then yields novel ring expansion products. Reaction of (R)- carvone provides an unusual example leading to the formation of a tricyclic dione. The ...