Formal enantioselective total synthesis of bisdehydroneostemoninine.

A formal enantioselective total synthesis of bisdehydroneostemoninine employing L-glutamic acid as the chiral pool is described. The key features of the synthesis include regioselective and enantioselective opening the chiral epoxide with dimethylsulfonium methylide and tandem Friedel-Crafts cyclization followed by lactonization to form the 5-7-5 tricyclic core of the target stemona alkaloids. The synthetic route provides opportunities to explore the biological behavior of enantiopure bisdehydroneostemoninine. [Formula: see text].