Catalytic cross-coupling of alkylzinc halides with α-chloroketones

The cross-coupling of alkylzinc halides with α-chloroketones catalyzed by Cu(acac)₂ is described. Using this method, primary and secondary alkyl groups are introduced adjacent to a ketone carbonyl under mild reaction conditions and in good yield. Cyclic, acyclic, aromatic, and aliphatic α-chloroketones are suitable substrates. Optically active α-chloroketones are converted to optically active products. The reaction was found to proceed stereospecifically with inversion of stereochemistry. The reaction is proposed to occur by direct substitution of the chloride with the alkyl group of an organocopper, -magnesium, or -zinc species.