Efficient tin hydride-mediated radical cyclisation of secondary amides leading to substituted pyrrolidinones. Part 2. Application to the synthesis of aromatic kainic acid analogues

Abstract

An enantioselective synthesis of phenyl allokainoid, starting from D-serine, is reported. Tin-mediated cyclisation of a secondary amide was used in the key step to produce a trisubstituted pyrrolidinone in excellent yield (ca. 80%). The predominant formation of the all-trans diastereoisomer is consistent with a reversible cyclisation to give the thermodynamically more stable product.