Total Synthesis of (±)-Jamtine Using a Thionium/N-Acyliminium Ion Cascade

The first total synthesis of (±)-jamtine (4), a tetrahydroisoquinoline alkaloid reputed for its therapeutic properties, is described. The key step involves a tandem thionium/N-acyliminium ion cyclization from enamido sulfoxide 13. The cascade process takes place with high diastereoselectivity and in excellent yield.