One-pot (1-ethoxycarbonylcyclopropyl)triphenylphosphonium tetrafluoroborate ring-opening and Wittig reaction.

An efficient method was developed for the synthesis of 2-methylene-4-substituted ethyl butyrates via cyclopropyl opening followed by a Wittig reaction. The desired products were formed in a two-step, one-pot reaction sequence. Alternatively, the key intermediate ylide 2 was isolable and could be stored under oxygen-free conditions and subsequently utilized. A variety of nucleophiles were found to open the commercially available cyclopropane 1. The resulting ylide reacted with aldehydes to provide E-olefinic products.