Abstract
Herein, we report the first highly enantioselective Ni-catalyzed arylation and alkenylation of simple aldehydes using readily available and stable organoboronic esters. This protocol provides various chiral secondary alcohols in high yields and enantioselectivities (up to 97% ee) with a broad scope of substrates, functional groups, and heterocycles. The use of a bulky N-heterocyclic carbene (NHC) ligand for nickel catalyst is the key to high enantiocontrol. The competitive Ni-catalyzed transformations, including Tishchenko reaction, dehydrogenation/hydrogenation reaction, and Suzuki-Miyaura couplings, are avoided. The excellent chemoselectivity is likely due to the application of mild base CsF and eta(2)-coordination of aldehydes with nickel.
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