Enantioselective synthesis of 2-substituted tetrahydro-β-carboline derivatives via the asymmetric transfer hydrogenation

Several 1-substituted-3,4-dihydro-beta-carboline derivatives were subjected to asymmetric transfer hydrogenation catalysed by chiral ruthenium complexes to give both enantiomers of 1,2,3,4-tetrahydro-beta-carbolines of high optical purity and in good yields. The absolute stereochemistry of 4c was established on the basis of X-ray analysis of its Mosher amide. (c) 2005 Elsevier B.V. All rights reserved.