Synthesis and transformations of metallacycles 41.☆ Cyclomagnesiation of O-containing 1,2-dienes with Grignard reagents in the presence of Cp2TiCl2

A Cp2TiCl2-catalyzed intermolecular homocyclomagnesiation of O-containing 1,2-dienes and cross-cyclomagnesiation of O-containing 1,2-dienes with aliphatic 1,2-dienes of cyclic and acyclic structure have been accomplished using Grignard reagents, which led to mono- and bicyclic organomagnesium compounds in 61-94% yields.