[(2R,4S,6R,8R,10S)-4-acetoxy-8-hydroxymethyl-10-methyl-10-triethylsilanyloxy-1,7-dioxaspiro[5.5]undec-2-yl]acetic acid tert-butyl ester

[(2R,4R,6S)-6-((2RS,6R)-7-benzyloxy-2-hydroxy-4-oxo-6-triethylsilanyloxyheptyl)-2-(4-methoxyphenyl)-[1,3]dioxan-4-yl]acetic acid tert-butyl ester

[(2R,4S,6R,8R)-8-benzyloxymethyl-4-hydroxy-10-oxo-1,7-dioxaspiro[5.5]undec-2-yl]acetic acid tert-butyl ester

[(2R,4S,6R,8R,10S)-8-benzyloxymethyl-4,10-dihydroxy-10-methyl-1,7-dioxaspiro[5.5]undec-2-yl]acetic acid tert-butyl ester

tert-butyl 2-[(6S,4R)-6-(hydroxymethyl)-2-(4-methoxyphenyl)-1,3-dioxan-4-yl]acetate

tert-butyl (2S,4R,6S)-2-(4-methoxyphenyl)-6-(2-oxoethyl)-[1,3]dioxan-4-ylacetate