Alkoxycarbonylmethylation of(3R, 10bS)-3-Phenyl-2, 3, 5, 6-tetrahydro-10bH-oxazolo[2, 3-a]isoquinoline

As part of a series of studies on synthesis of chiral 1-alkyltetrahydroisoquinolines, asymmetric synthesis of 1-alkoxycarbonylmethyl-1, 2, 3, 4-tetrahydroisoquinolie (IV) was investigated. Two synthetic approaches using intermolecular and intramolecular Reformatsky-type reactions from (3R, 10bS)-3-phenyl-2, 3, 5, 6-tetrahydro-10bH-oxazolo[2, 3-a]isoquinoline (1) were attempted, but high stereoselectivity could not be obtained. For the purpose of determining the absolute structures of the compounds (2, 3) obtained by the Reformatsky-type reactions, transformation of 3a to a chiral 1, 3, 4, 6, 7, 11b-hexahydro-2H-benzo[a]quinolizine (14) was investigated.