(1aS,2S,10R,10aR)-2,7-bis((tert-butyldiphenylsilyl)oxy)-3,8-dimethoxy-10a-methyl-9-oxo-1a,9,10,10a-tetrahydro-2H-benzo[6,7]fluoreno[2,3-b]oxiren-10-yl acetate

(1aS,2S,10R,10aR)-2,7-bis((tert-butyldiphenylsilyl)oxy)-3,8-dimethoxy-10a-methyl-9-(2-(methylsulfonyl)hydrazineylidene)-1a,9,10,10a-tetrahydro-2H-benzo[6,7]fluoreno[2,3-b]oxiren-10-yl acetate

(1aS,2S,10R,10aR)-2,7-bis((tert-butyldiphenylsilyl)oxy)-9-diazo-10a-methyl-3,8-dioxo-1a,3,8,9,10,10a-hexahydro-2H-benzo[6,7]fluoreno[2,3-b]oxiren-10-yl acetate

(1aS,2S,10R,10aR)-10-acetoxy-3,8-dimethoxy-7-(methoxymethoxy)-10a-methyl-9-oxo-1a,9,10,10a-tetrahydro-2H-benzo[6,7]fluoreno[2,3-b]oxiren-2-yl 4-azidobutanoate

(7R,7aR,8aS,9S)-7-acetoxy-1-hydroxy-11-methoxy-7a-methyl-6-oxo-7,7a,8a,9-tetrahydro-6H-benzo[h]oxireno[2',3':4,5]benzo[1,2-c]chromen-9-yl 4-azidobutanoate