Multigram Synthesis of Glyceollin I

Scaled-up procedures and preparation of glyceollin I in multigrarn quantities are described. The synthesis features construction of a cis-fused ring system in high enantiomeric excess after Sharpless asymmetric dihydroxylation of a key intermediate that is initially produced by an intramolecular Wittig reaction to afford the requisite alkene while simultaneously forming the first ring. The overall yield is 12% after 11 steps.