Competition of (3+2) annulation and (3+2) cycloaddition in the reaction of alkenes with donor-acceptor cyclopropanes
摘要
Lewis acid-initiated reaction of (het)aryl-substituted donor-acceptor cyclopropanes with styrenes was studied. The initiation of the process by tin(IV) chloride caused the reaction to proceed in two alternative directions, namely, with the formation of substituted cyclopentanes ((3+2) cycloaddition products) and substituted indanes or their hetero analogs ((3+2) annulation products). The chemoselectivity of the reaction was controlled by several factors, such as the reaction conditions and the nature of reacting compounds and initiator.