Synthesis of (+)-trans-Dihydrolycoricidine by an Organocatalytic Enantioselective Friedel-Crafts Reaction

The amaryllidaceae alkaloid (+)‐trans‐dihydrolycoricidine (1) was synthesized by asymmetric organocatalytic Friedel–Crafts reaction of sesamol with nitro‐olefin followed by an intramolecular Henry reaction for construction of the C ring system. Construction of the B ring was achieved by a microwave‐assisted palladium‐catalyzed CO insertion reaction. Finally, regio‐ and stereoselective introduction of the third hydroxyl group (at C3) on the C ring afforded 1. Organocatalyzed FC: Enantioselective synthesis of antitumor alkaloid, trans‐dihydrolycoricidine, was achieved by means of a 1,4‐type Friedel–Crafts reaction by using a guanidine/bisthioure organocatalyst, followed by an intramolecular Henry reaction for construction of the C ring system.