Enantioselective total synthesis of (-)-myrifabral A and B.

A catalytic enantioselective approach to the Myrioneuron alkaloids (-)-myrifabral A and (-)-myrifabral B is described. The synthesis was enabled by a palladium-catalyzed enantioselective allylic alkylation, that generates the C(10) all-carbon quaternary center. A key N-acyl iminium ion cyclization forged the cyclohexane fused tricyclic core, while vinyl boronate cross metathesis and oxidation afforded the lactol ring of (-)-myrifabral A. Adaptation of previously reported conditions allowed for the conversion of (-)-myrifabral A to (-)-myrifabral B.