Synthesis of Tetrahydroisoquinoline Alkaloids via Anodic Cyanation as the Key Step

We report a new route to tetrahydroisoquinoline (THIQ) alkaloids involving the alkylation of alpha-aminonitrile 2 as a key step. The latter compound was prepared by anodic cyanation of the corresponding tertiary amine 1. Reductive decyanation of alpha-aminonitriles 6a-c proceeded diastereoselectively (up to 95% de) to deliver the Cl-substituted alkaloids precursors 9a-c. The syntheses of (+/-)-carnegine, (+/-)-norlaudanosine, and (+/-)-O,O-dimethylcoclaurine have been achieved.