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.