Synthesis of C-1 indol-3-yl substituted tetrahydroisoquinoline derivatives via a Pictet–Spengler approach

A protocol for the diastereoselective synthesis of C-1 indol-3-yl substituted tetrahydroisoquinoline derivatives via Pictet–Spengler condensation with L-DOPA or l-DOPA derivatives and 1H-indole-3-carbaldehydes is presented. The protocol is used for the successful synthesis of several tetrahydroisoquinolines as well as diketopiperazine fused analogues.