Enantioselective Synthesis of 1-Aryltetrahydroisoquinolines

Significance

1,2,3,4-Tetrahydroisoquinolines (THQs) 2 are an important motif often encountered in alkaloids and pharmaceutical targets (see Review below). The authors describe the synthesis of 1-aryl THQs through a 1,2-addition of boronic acids to 3,4-dihydroisoquinoline N-oxides 1 using zinc. The addition of nucleophiles to 1 is not an uncommon strategy and the authors expand the scope of this reaction. Following up on their earlier report of reactions of styrylboronic esters (Org. Lett. 2006, 8, 3979) the authors find that arylboroxines and arylboronic esters react with ­diethylzinc and an amino acid derived ligand to give products 2 with high enantioselectivity and good yields.

Review: J. D. Scott, R. M. Williams Chem. Rev. 2002, 102, 1669-1730.