Reaction of α-(N-carbamoyl)alkylcuprates with propargyl substrates:: Synthetic route to a-amino allenes and Δ3-pyrrolines

[GRAPHICS] Carbamate deprotonation followed by treatment with CuCN center dot 2LiCl affords alpha-(IV-carbamoyl)-alkylcuprates which react with propargyl halides, mesylates, tosylates, phosphates, acetates, and epoxides to give alpha-(N-carbamoyl) allenes via an anti-S(N)2' substitution process. Propargyl halides, sulfonates, and phosphates give good yields of carbamoyl allenes, while the acetates afford low yields. Propargyl substrates undergo regiospecific S(N)2' substitution in the absence of severe steric hindrance. The a-(N-carbamoyl) allenes can be cyclized to 2-oxazolidinones or deprotected to afford the free amines which can be cyclized to Delta(3)-pyrrolines with either AgNO3 or Ru-3(CO)(12).