A Regio- and Enantioselective CuH-Catalyzed Ketone Allylation with Terminal Allenes

We report a method for the highly enantioselective CuH-catalyzed allylation of ketones that employs terminal allenes as allylmetal surrogates. Ketones and allenes bearing diverse and sensitive functional groups are efficiently coupled with high stereoselectivity and exclusive branched regioselectivity. In stoichiometric experiments, each elementary step of the proposed hydrocupration–addition–metathesis mechanism can be followed by NMR spectroscopy.