α-Olefins as Alkenylmetal Equivalents in Catalytic Conjugate Addition Reactions


  • Support for this work was provided by the National Institute of General Medical Sciences (GM-063755). C.-Y.H. and H.O. thank the Croucher Foundation and the JSPS, respectively, for postdoctoral fellowships. We are grateful to Dr. Li Li for obtaining mass spectrometric data for all compounds (MIT Department of Chemistry Instrumentation Facility, which is supported in part by the NSF (CHE-9809061 and DBI-9729592) and the NIH (1S10RR13886-01)).


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In the presence of a silyl triflate and an amine base, a nickel–phosphine complex catalyzes the direct conjugate addition of ethylene, α-olefins, and aryl alkenes to unsaturated aldehydes and ketones. The enolsilane products are isolated in good to very high yield, and in very high stereoselectivity for some cases. The alkene is a functional equivalent of an alkenylmetal reagent in the transformation.