(+/-)-(1α,2α,4aα,4bβ,10β)-8,8-(Ethylenedioxy)-2,7-dihydroxy-10-(methoxycarbonyl)-1-methylgibbane-1,4a-carbolactone

methyl (1'S,2'S,4a'R,4b'R,7'S,9a'R,10'S,10a'R)-2'-(benzoyloxy)-7'-hydroxy-1'-methyl-13'-oxo-1',2',4b',5',6',7',10',10a'-octahydro-9'H-spiro[[1,3]dioxolane-2,8'-[4a,1](epoxymethano)[7,9a]methanobenzo[a]azulene]-10'-carboxylate

methyl (1'S,2'R,3'R,4a'R,4b'R,7'S,9a'R,10'S,10a'R)-2'-(benzoyloxy)-3'-bromo-7'-hydroxy-1'-methyl-13'-oxodecahydro-9'H-spiro[[1,3]dioxolane-2,8'-[4a,1](epoxymethano)[7,9a]methanobenzo[a]azulene]-10'-carboxylate

methyl (1'S,2'R,3'S,4a'R,4b'R,7'S,9a'R,10'S,10a'R)-2',3',7'-trihydroxy-1'-methyl-13'-oxodecahydro-9'H-spiro[[1,3]dioxolane-2,8'-[4a,1](epoxymethano)[7,9a]methanobenzo[a]azulene]-10'-carboxylate

methyl (1S,2S,4aR,4bR,7S,9aR,10S,10aR)-2-(benzoyloxy)-7-hydroxy-1-methyl-8,13-dioxo-1,2,4b,5,6,7,8,9,10,10a-decahydro-4a,1-(epoxymethano)-7,9a-methanobenzo[a]azulene-10-carboxylate