Highly Diastereoselective Addition of the Lithium Enolate of α-Diazoacetoacetate to N-Sulfinyl Imines:  Enantioselective Synthesis of 2-Oxo and 3-Oxo Pyrrolidines

The highly enantioselective synthesis of 2-oxo and 3-oxo pyrrolidines has been achieved by diastereoselective addition of the lithium enolate of α-diazoacetoacetate to chiral N-sulfinyl imines, followed by photoinduced Wolff rearrangement or Rh(II)-catalyzed intramolecular N−H insertion.