Gravar-mail: (Z)-6-Hy­droxy-1a,5-dimethyl-8-[(morpholin-4-yl)meth­yl]-2,3,6,7,7a,8,10a,10b-octa­hydro­oxireno[2′,3′:9,10]cyclo­deca­[1,2-b]furan-9(1aH)-one