Highly efficient construction of an oxa-[3.2.1]octane-embedded 5-7-6 tricyclic carbon skeleton and ring-opening of the bridged ring via C-O bond cleavage

Concise syntheses of (-)-quinocarcinol methyl ester and (-)-oxa-quinocarcinol methyl ester

A concise synthesis of (-)-quinocarcinol methyl ester was accomplished with an overall yield of 39% through a 9-step longest linear sequence (LLS). Our synthesis features a two-step ester reduction/reductive amination sequence, a stereoselective [3 + 2] intramolecular cross-cycloaddition for the construction of bicyclo[3.2.1]octane skeletons, four simultaneous hydrogenolysis reactions in a one-pot process, and a stereoselective Krapcho decarboxylation. By following this protocol, (-)-oxa-quinocarcinol methyl ester was also achieved.

Total Synthesis of Resiniferatoxin

From both structural and functional perspectives, the large family of daphnane diterpene orthoesters (DDOs) represent a truly remarkable class of natural products. As potent lead compounds for the treatment of pain, neurodegeneration, HIV/AIDS, and cancer, their medicinal potential continues to be heavily investigated, yet synthetic routes to DDO natural products remain rare. Herein we report a distinct approach to this class of complex diterpenes, highlighted by a 15-step total synthesis of the flagship DDO, resiniferatoxin.