Diastereoselective alkylation of homochiral 1,2,3,4-tetrahydroisoquinolin-3-one. A potential route to enantiomerically pure 4-substituted tetrahydroisoquinolines

Article abstract of DOI:10.1016/0957-4166(96)00022-5

Enantiomerically pure 1,4-dihydroisoquinolin-3-one 1 was prepared in four steps with an overall yield of 60%. Alkylation of the corresponding lactam enolate has been studied and has proven to be highly diastereoselective. Thus, 4-substituted-1,4-dihydroisoquinolin-3-ones 7a-d were obtained in high chemical yields with up to 97% diastereoisomeric excesses.