Ring expansion reactions of ethyl cyclopropylideneacetate and benzosilacyclobutenes: formal σ bond cross metathesis

The ring expansion reaction of ethyl cyclopropylideneacetate (1) with benzosilacyclobutenes proceeded smoothly in the presence of Ni(cod)(2)-TOPP (tribiphenyl-2-yl phosphite) to give benzosilacycloheptenes in good yields. This formal sigma bond metathesis reaction proceeded in a selective manner. The Ni-catalyzed reaction of 1 with biphenylenes was also examined. (C) 2010 Elsevier Ltd. All rights reserved.