Cobalt-Catalyzed Asymmetric 1,4-Reduction of α,β-Unsaturated Nitriles with HBpin.

A series of novel AAO ligands were synthesized and employed in the cobalt-catalyzed asymmetric 1,4-reduction of α,β-unsaturated nitriles with HBpin, affording β-stereogenic alkyl nitriles with high enantioselectivities. This protocol can be scaled to gram quantities with a low catalyst loading (0.5 mol %) and demonstrates broad synthetic utility, as evidenced by the efficient transformation of the enantioenriched products into valuable chiral building blocks, including aldehydes, carboxylic acids, amides, and ketones.