Directed (R)- or (S)-Selective Dynamic Kinetic Enzymatic Hydrolysis of 1,2,3,4-Tetrahydroisoquinoline-1-carboxylic Esters

The first synthesis of both enantiomers of 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinotine-1-carboxylic acid was accomplished through dynamic kinetic resolution in procedures based on CAL-B- or subtilisin Carlsberg-catalysed enantioselective hydrolysis of the corresponding ethyl esters in aqueous NH4OAc buffer at pH 8.5. The products were obtained with high enantiopurity (92-93%ee) in good yields (85-92%). (R)-1,2,3,4-Tetrahydroisoquinotine-1-carboxylic acid was obtained with high enantiopurity (98%ee) and in good yield (85 %) in a CAL-B-catalysed process, under similar conditions. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)