Enantioselective Formal Total Syntheses of Didehydrostemofoline and Isodidehydrostemofoline through a Catalytic Dipolar Cycloaddition Cascade


  • We thank the National Institutes of Health (GM 25439 and GM 31077) and The Robert A. Welch Foundation (F-0652) for their generous support. D.H.P. thanks NIH for a postdoc fellowship (GM096557).


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Sweet to the core: Enantioselective formal total syntheses of the title compounds were accomplished in 24 steps from 2-deoxy-D-ribose. The synthesis features a novel cascade of reactions culminating in an intramolecular dipolar cycloaddition to form the tricyclic core of the stemofoline alkaloids from an acyclic diazo imine intermediate.