Regioselective Carbozincation and Further Functionalization of Allenamides Catalyzed by an N‐Heterocyclic Carbene (NHC)‐Copper Complex

Abstract

An efficient protocol for the carbozincation of allenamides with dialkylzinc reagents catalyzed by an NHC‐Cu complex has been developed. This protocol could provide alkenylzinc species introducing the alkyl group to γ‐position and the zinc component to β‐position of the allenamides in a regio‐ and stereoselective manner. The resulting alkenylzinc species can undergo further C‐C bond‐forming reactions, such as allylation, arylation, and benzoylation, affording a variety of β,β‐disubstituted enamides with well‐controlled configurations of the two substituents. Moreover, the chiral allenamide synthesized via this method can be converted to a chiral aminocyclopropane derivative. In view of the high regio‐ and stereoselectivity and the convenient one‐pot procedure, this sequential transformation protocol offers a potentially useful method for synthesizing multi‐substituted enamides, which are important compounds in synthetic organic chemistry.