Dearomatising cyclisation of lithiated l-naphthamides with a phenylglycinol-derived chiral auxiliary: asymmetric synthesis of an arylkainoid and a kainoid-like pyroglutamate

1-Naphthamides of N-benzylphenylglycinols undergo a diastereoselective dear omatising cyclisation on treatment with t-BuLi and DMPU or HMPA. A new pyrr olidinone ring is formed bearing three new stereogenic centers of defined a bsolute stereochemistry. Removal of the phenylglycinol auxiliary gives enan tiomerically pure substituted lactams exhibiting the stereochemistry of the kainoids. These may be converted to kainoid-like pyroglutamates, or altern atively, using the method of the previous paper, to analogues of acromelic acid. (C) 2001 Elsevier Science Ltd. All rights reserved.