Catalylic diastereo- and enantioselective hydroalkylation of 3,3-disubstituted cyclopropenes with Co-homoenolate generated in situ from ring-opening of easily accessible cyclopropanols promoted by a chiral phosphine-cobalt complex is presented. Such a process represents the unprecedented and direct introduction of a wide range of functionalized alkyl groups without the need of pre-formation of stoichiometric amounts of organometallic reagents onto the cyclopropane motif, affording multi-substituted cyclopropanes in up to 99 % yield with >95:5 dr and 98:2 er. Functionalization of the products delivered enantioenriched cyclopropanes that are otherwise difficult to access.
Keywords: cobalt; cyclopropanes; enantioselective catalysis; hydroalkylation; small rings.
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