Direct and Asymmetric Nickel(II)-Catalyzed Construction of Carbon-Carbon Bonds from N-Acyl Thiazinanethiones.

A wide array of new N-acyl thiazinanethiones are employed in a number of direct and enantioselective carbon-carbon-bond-forming reactions catalyzed by nickel(II) complexes. The electrophilic species are mostly prepared in situ from ortho esters, methyl ethers, acetals, and ketals, which makes the overall process highly efficient and experimentally straightforward. Theoretical calculations indicate that the reactions proceed through an open transition state in a SN1-like mechanism. The utility of this novel procedure has been demonstrated by the asymmetric preparation of synthetically useful intermediates and the total synthesis of peperomin D.