Nickel-Catalyzed Guerbet Type Reaction: C-Alkylation of Secondary Alcohols via Double (de)Hydrogenation.

Acceptorless double dehydrogenative cross-coupling of secondary and primary alcohols under nickel catalysis is reported. This Guerbet type reaction provides an atom- and a step-economical method for the C-alkylation of secondary alcohols under mild, benign conditions. A broad range of substrates including aromatic, cyclic, acyclic, and aliphatic alcohols was well tolerated. Interestingly, the C-alkylation of cholesterol derivatives and the double C-alkylation of cyclopentanol with various alcohols were also demonstrated.