1H-Phenanthro[10,1-de][1,3]dioxepin-2(4H)-one,3-ethenyl-7a,8,8a,9,10,11,12,12a,12b,12c-decahydro-6,6,9,9,12a-pentamethyl-,[7aS-(7aa,8aa,12ab,12ba,12cb)]-