Manganese-Catalyzed Hydrogen-Autotransfer C−C Bond Formation: α-Alkylation of Ketones with Primary Alcohols

A novel catalytic hydrogen‐autotransfer protocol for the atom‐efficient α‐alkylation of ketones with readily available alcohols is presented. The use of manganese complexes bearing non‐innocent PNP pincer ligands enabled the functionalization of a broad range of valuable ketones, including 2‐oxindole, estrone 3‐methyl ether, and testosterone. Mechanistic investigations suggest the participation of an intramolecular amidate‐assisted alcohol‐dehydrogenation process. Something borrowed, something new: A hydrogen‐autotransfer reaction catalyzed by manganese(I) PNP pincer complexes was developed for the α‐alkylation of ketones with alcohols (see scheme). Structurally diverse primary alcohols were used to functionalize a wide range of ketones, including 2‐oxindole, estrone 3‐methyl ether, and testosterone, by this straightforward method.