Total synthesis of (+)-crocacin C using hidden symmetry.

A highly convergent and protecting-group-free synthesis of (+)-crocacin C, featuring an enzymatic enantioselective desymmetrization of a meso-diol, a base-induced ring opening of a THP ring, and a one-pot hydrostannylation/Stille coupling as the key steps, is reported. The natural product was obtained in 11 steps and 22.3% overall yield starting from readily available oxabicycle 1. Finally, a unique enantioselective step, an enzymatic desymmetrization, revealed four stereogenic centers and created one in C4 of the THP furnishing the dense building block 4 with high enantioselectivity (ee >98%).