(1aR)-5β,6β-Bis(benzoyloxy)-1aα,2,5,5a,6,9,10,10aα-octahydro-5aβ-hydroxy-4-(hydroxymethyl)-1,1,7,9α-tetramethyl-1H-2α,8aα-methanocyclopenta[a]cyclopropa[e]cyclodecen-11-one