A versatile approach to cis-5-substituted 4-hydroxy-2-pyrrolidinones: asymmetric synthesis of angiogenesis inhibitor streptopyrrolidine

Stereoselective formation of chiral trans-4-hydroxy-5-substituted 2-pyrrolidinones: syntheses of streptopyrrolidine and 3-epi-epohelmin A

A highly diastereoselective approach for synthesis of trans-4-hydroxy-5-substituted 2-pyrrolidinones has been developed. The streptopyrrolidine and 3-epi-epohelmin A were synthesized by this one-pot cascade protocol.

Simple, versatile, and chemoselective reduction of secondary amides and lactams to amines with the Tf2O–NaBH4 or Cp2ZrHCl–NaBH4 system

A convenient method for the direct reduction of secondary amides and lactams to amines is reported.

Stereoselective synthesis of four possible isomers of streptopyrrolidine

The synthesis of (4R,5R)-streptopyrrolidine (1), (4S,5R)-streptopyrrolidine (2) (4R,5S)-streptopyrrolidine (3) and (4S,5S)-streptopyrrolidine (4) have been achieved in a concise and highly efficient manner via a highly stereoselective aldol type reaction with the trimethylsilyl enolate of ethyl acetate and Lewis acid mediated lactamization as the key reactions in ≈42% yield over six steps starting from D-phenylalanine and L-phenylalanine, respectively. The absolute configuration of the natural product was shown to be (4S,5S) by comparing its spectral and analytical data with the reported values.