Highly diastereoselective addition of the lithium enolate of alpha-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 alpha-diazoacetoacetate to chiral N-sulfinyl imines, followed by photoinduced Wolff rearrangement or Rh(II)-catalyzed intramolecular N-H insertion.