Manganese(I)-Catalyzed α-Alkenylation of Ketones Using Primary Alcohols.

A simple protocol of manganese catalyzed selective α-alkenylation of ketones using primary alcohols is reported. The reactions proceeded well with a low loading of catalyst (0.3 mol %). The overall transformation operates through O-H bond activation of primary alcohols via dearomatization-aromatization metal ligand cooperation in the catalyst to provide the corresponding aldehydes, which further undergo condensation with methylene ketones to deliver α,β-unsaturated ketones. This selective α-alkenylation proceeds with the release of water and liberation of molecular hydrogen.