oxepino<3,2-b>pyrano<2',3':5,6>pyrano<2,3-f>oxepin, 2-<(2,2,2-trimethylacetoxy)methyl>-4,10-dihydroxy-9-<1-<(tert-butyldimethylsilyl)oxy>propyl>hexadecahydro-5a,10-dimethyl-, <2R-<2α,4α,4aβ,5aβ,7aβ,9α,10β,12aα,13aα,14aα>>-