[(2R,4S,6S,8S,10S)-4-(tert-Butyl-dimethyl-silanyloxy)-10-hydroxy-8-((2S,3S)-2-hydroxy-3-methyl-4-triethylsilanyloxy-butyl)-10-methyl-1,7-dioxa-spiro[5.5]undec-2-yl]-acetic acid tert-butyl ester

[(2R,4S,6S,8S,10S)-8-[(2S,3R)-4-((R)-4-Benzyl-2-oxo-oxazolidin-3-yl)-2-hydroxy-3-methyl-4-oxo-butyl]-4-(tert-butyl-dimethyl-silanyloxy)-10-hydroxy-10-methyl-1,7-dioxa-spiro[5.5]undec-2-yl]-acetic acid tert-butyl ester

[(2R,4S,6S,8S,10S)-4-(tert-Butyl-dimethyl-silanyloxy)-10-methyl-8-((R)-3-methyl-2-methylene-4-triethylsilanyloxy-butyl)-10-triethylsilanyloxy-1,7-dioxa-spiro[5.5]undec-2-yl]-acetic acid tert-butyl ester