A versatile approach to cis-5-substituted 4-hydroxy-2-pyrrolidinones: asymmetric synthesis of angiogenesis inhibitor streptopyrrolidine
摘要:
A concise, flexible, and highly diastereoselective approach to cis-5-alkyl-4-hydroxy-2-pyrrolidinones 1 is described. The key step is an ammonium acetate-assisted catalytic hydrogenation of the enamides 9, derived in two steps from malimides 6a,b as we have described previously. The method was applied to the asymmetric synthesis of streptopyrrolidine 5, a natural product, which exhibited significant anti-angiogenesis activity. (C) 2009 Elsevier Ltd. All rights reserved.
Versatile One-Pot Reductive Alkylation of Lactams/Amides via Amide Activation: Application to the Concise Syntheses of Bioactive Alkaloids (±)-Bgugaine, (±)-Coniine, (+)-Preussin, and (−)-Cassine
Direct entry: One‐pot reductivealkylation of lactams/amides with Grignard reagents has been realized vialactam/amideactivation with Tf2O. This method opens a direct entry to α‐alkylated amines. The versatility of the method is illustrated by the concisesyntheses of bioactivealkaloids (±)‐bgugaine, (±)‐coniine, (+)‐preussin, and (−)‐cassine.