3a,4a-Epoxy-8H-cyclopent[a]-s-indacen-8-one,1,7-dibromo-1,2,3,3b,4,5,6,7,7a,8a-decahydro-3b-hydroxy-2,4,6,6,8a-pentamethyl-,[1S-(1a,2b,3aa,3bb,4b,4aa,7a,7aa,8ab)]-