Carbon-carbon bonds, including those between sp 3 -hybridized carbons (alkyl-alkyl bonds), typically comprise much of the framework of organic molecules. In the case of sp 3 -hybridized carbons, the carbon can be stereogenic, and the particular stereochemistry can have implications for structure and/or function 1 , 2 , 3 . As a consequence, the development of methods that simultaneously construct alkyl-alkyl bonds and control stereochemistry is a highly important, as well as a challenging, objective. Herein, a new strategy for enantioselective alkyl-alkyl bond formation is described, wherein a racemic alkyl electrophile is coupled with an olefin in the presence of a hydrosilane, through the action of a chiral nickel catalyst. Families of racemic alkyl halides, including tertiary substrates, that have not previously proved to be suitable for enantioconvergent couplings with alkylmetal nucleophiles are shown to cross-couple with olefins with good enantioselectivity and yield under very mild conditions. Given the ready availability of olefins, this new approach opens the door to the development of ever more general and powerful methods for enantioconvergent alkyl-alkyl coupling.

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A new organocatalytic transfer hydrogenation strategy for the asymmetric synthesis of 1,1-diarylethanes is described. Under mild conditions, a range of 1,1-diarylethanes substituted with an o-hydroxyphenyl or indole unit could be obtained with excellent efficiency and enantioselectivity. We also extended the protocol to an unprecedented asymmetric hydroarylation of 1,1-diarylalkenes with indoles for the synthesis of a range of highly enantioenriched 1,1,1-triarylethanes bearing acyclic all-carbon quaternary stereocenters. These diaryl- and triarylethanes exhibit impressive cytotoxicity against a number of human cancer cell lines. Preliminary mechanistic studies combined with DFT calculations provided important insight into the reaction mechanism.