Catalytic enantioconvergent coupling of secondary and tertiary electrophiles with olefins. (15th November 2018) - Wang, Zhaobin
Abstract Carbon–carbon bonds, including those betweensp 3 -hybridized carbon atoms (alkyl–alkyl bonds), typically comprise much of the framework of organic molecules. In the case ofsp 3 -hybridized carbon, the carbon can be stereogenic and the particular stereochemistry can have implications for structure and function1–3 . As a consequence, the development of methods that simultaneously construct alkyl–alkyl bonds and control stereochemistry is important, although challenging. Here we describe a strategy for enantioselective alkyl–alkyl bond formation, in which a racemic alkyl electrophile is coupled with an olefin in the presence of a hydrosilane, rather than via a traditional electrophile–nucleophile cross-coupling, through the action of a chiral nickel catalyst. We demonstrate that families of racemic alkyl halides—including secondary and tertiary electrophiles, which have not previously been shown to be suitable for enantioconvergent coupling with alkyl metal nucleophiles—cross-couple with olefins with good enantioselectivity and yield under very mild reaction conditions. Given the ready availability of olefins, our approach opens the door to developing more general methods for enantioconvergent alkyl–alkyl coupling. Nickel-catalysed coupling of racemic alkyl electrophiles and olefins in the presence of a hydrosilane is achieved with good enantioselectivity and yield under very mild reaction conditions.