(4aS,4bS,10aS,10bR,11S,12aS)-10b-fluoro-11-hydroxy-10a,12a-dimethyl-3,4,4a,5,6,10a,10b,11,12,12a-decahydro-2H-naphtho[2,1-f]chromene-2,8(4bH)-dione