Domino Heck–Diels–Alder Reactions of Differently Substituted Cyclopropylallenes

Abstract

Abstract Several substituted cyclopropylallenes were coupled under Heck conditions with aryl iodides and aryl bromides, respectively, and the 1,3,5‐hexatrienes resulting with ring‐opening of the cyclopropyl group, were captured in situ by a number of reactive dienophiles to yield oligosubstituted cyclohexene derivatives (8–86 %, 33 examples) with diastereomeric ratios ranging from 1.4:1 to 4.9:1. The influences of the number, the nature and the pattern of substituents have been elaborated. The [4+2] cycloaddition most probably proceeds in two steps through a mesomerically well stabilized 1,6‐zwitterionic intermediate. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)