Quick assembly of 1-alkylidenyl-tetrahydroisoquinolines via a Catellani reaction/NBS-mediated cyclization sequence and synthetic applications

We herein disclose a modular synthesis of 1-bromomethylene-THIQs involving a Catellani reaction of aryl iodides, aziridines, and terminal alkynes followed by an N -bromosuccinimide (NBS)-mediated cyclization. This approach features mild reaction conditions, wide substrate scope, good step-economy and good scalability. Based on this new method, we have accomplished the concise total synthesis of (±)-cularine, formal synthesis of 8-oxopseudopalmatine as well as the first total synthesis of dactyllactone A, demonstrating the wide synthetic potential of this method.