Substrate controlled, regioselective carbopalladation for the one-pot synthesis of C4-substituted tetrahydroisoquinoline analogues.

6- cyclization reaction through regioselective carbopalladation was demonstrated with -(2-halobenzyl)--allylamines to furnish the corresponding C4-substituted tetrahydroisoquinoline derivatives. The scope of the reaction was extended to the synthesis of C4-quaternary tetrahydroisoquinoline derivatives also. The nature of the substituent on the olefin moiety dictates the course of the carbopalladation sequence.