On the regiochemistry of cyclialkylation of regiodefined 4-halo-1-alkenylmetals producing cyclobutenes

Article abstract of DOI:10.1016/S0040-4039(97)00011-7

A combination of recently developed anti-carbometallation of homopropargyl alcohols and cyclialkylation of 4-halo-1-alkenyllithiums of appropriate stereochemistry and regiochemistry provides, for the first time, a regiospecific procedure for the synthesis of regiodefined cyclobutenes presumably via σ-type cyclialkylation, whereas carboalumination of 4-halo-1-alkynylmetals containing Si or Al leads to regioconvergent cyclobutene formation.