Synfacts 2007(5): 0516-0516  
DOI: 10.1055/s-2007-968460
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Quaternary Carbon Stereocenters via NHC-Cu Induced Conjugate Addition

Contributor(s): Hisashi Yamamoto, Joshua N. Payette
M. K. Brown, T. L. May, C. A. Baxter, A. H. Hoveyda*
Boston College, Chestnut Hill, USA
Further Information

Publication History

Publication Date:
24 April 2007 (online)

Significance

A new chiral N-heterocyclic carbene (NHC) promotes the Cu-catalyzed conjugate addition of alkylzinc reagents to cyclic γ-keto esters. This system accommodates sterically congested electrophilic sites to yield products containing quaternary carbon centers in significantly higher yields and ee values than previously reported systems. Further, selective in situ reduction of the ester moiety of the product conveniently affords chiral material amenable to further manipulation.