Concerning the Potential Reversibility of Carbometalation in Alkoxide-directed Ti(Oi-Pr)4-mediated Reductive Cross-Coupling of Homoallylic Alcohols with Aromatic Imines

摘要

In an attempt to understand the nature of selectivity in Ti-mediated reductive cross-coupling between homoallylic alcohols and imines, we investigated whether thermodynamic equilibration of the presumed organometallic intermediate plays a role in selectivity. No evidence could be found for olefin exchange in preformed azatitanacyclopentanes – an observation that is consistent with a model based on kinetically controlled selective carbometalation.