Total syntheses of crinine and related alkaloids

Cyclizations of a bicyclic amine via an intramolecular Heck reaction followed by an oxidation reaction generated a tetracyclic spirocyclohexadione. From this useful intermediate, different crinine alkaloids such as crinine, buphanisine, flexinine, and augustine could be synthesized. Dienol/benzene or dienone/phenol rearrangement of this tetracyclic spirodienone afforded apogalanthamine analogs. [Display omitted]