Versatile Cobalt-Catalyzed Enantioselective Entry to Boryl-Functionalized All-Carbon Quaternary Stereogenic Centers

We report an asymmetric synthesis of chiral boryl-functionalized gamma-lactams containing all-carbon quaternary stereocenters via a Co-catalyzed enantioselective hydroboration/cyclization of amide-tethered 1,6-enynes. These enantio-enriched gamma-lactam products can be readily converted to a variety of cyclic and acyclic other chiral gamma-lactams, pyrrolidin-2,3-diones, beta-amino acid N-carboxyanhydrides, and beta-amino carboxylic amides.