Catalytic Enantioselective Synthesis of β-Lactams: Intramolecular Kinugasa Reactions and Interception of an Intermediate in the Reaction Cascade

Authors


  • Support has been provided by the National Institutes of Health (National Institute of General Medical Sciences, R01-GM066960), Merck, and Novartis. Funding for the MIT Department of Chemistry Instrumentation Facility has been furnished in part by NSF CHE-9808061 and NSF DBI-9729592. We thank Ivory D. Hills for an X-ray crystallographic study.

Abstract

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A planar-chiral Cu/phosphaferrocene–oxazoline catalyst mediates intramolecular Kinugasa reactions to give tricyclic β-lactams with good enantioselectivity. A variant of the process, in which a postulated enolate intermediate is intercepted with an electrophile in a transformation that generates two C[BOND]C bonds, a C[BOND]N bond, two new rings, a carbonyl group, and adjacent tertiary and quaternary stereocenters (see scheme), supports the proposed mechanism.

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