1,6-Dioxaspiro[3.4]octane-7-carboxaldehyde, 5-[3,4-dihydro-3-[(4-methoxyphenyl)methyl]-2,4-dioxo-1(2H)-pyrimidinyl]-8-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-, (4R,5R,7S,8R)-

2,4(1H,3H)-Pyrimidinedione, 1-[(4R,5R,7R,8R)-8-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-7-[[[(1,1-dimethylethyl)dimethylsilyl]oxy]methyl]-1,6-dioxaspiro[3.4]oct-5-yl]-3-[(4-methoxyphenyl)methyl]-