Spiro[2a,6a-epoxynaphth[2,3-b]oxirene-2(1aH),2'-naphtho[1,8-de][1,3]dioxin]-3(6H)-one,7,7a-dihydro-6,7-dihydroxy-, [1aR-(1aa,2ab,6a,6ab,7b,7aa)]-