Diastereoselective protonation of lactam enolates derived from (R)-phenylglycinol. A novel asymmetric route to 4-phenyl-1,2,3,4-tetrahydroisoquinolines

[GRAPHICS] Highly diastereoselective protonation of chiral lactam enolates of 4-substi tuted-7,4-dihydroisoquinolin-3-ones is reported. Protonation and alkylation processes of these lactam enolates derived from phenylglycinol occur with opposite diastereofacial selectivity, This diastereoselective protonation h as been applied to the asymmetric synthesis of (4S)-N-methyl-4-phenyl-1,2,3 ,4-tetrahydroisoquinoline 9 obtained in up to 97% ee.