(αS,1R,3aS,4E,7aR)-4-[(2E)-[(3S,5R)-3,5-Bis[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-methylenecyclohexylidene]ethylidene]octahydro-α,7a-dimethyl-1H-indene-1-acetaldehyde; [1R-[1α(S*),3aβ,4E(1E,3S*,5R*),7aα]]-4-[[3,5-Bis[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-methylenecyclohexylidene]ethylidene]octahydro-α,7a-dimethyl-1H-indene-1-acetaldehyde; (1S,3R,5E,7E)-1,3-Bis[(tert-butyldimethylsilyl)oxy]-9,10-secopregna-5,7,10(19)-triene-20-carboxaldehyde; CLP 8

Intermediate in the preparation of Vitamin D analogs.