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

1-[(2S,4S,6R,8R,10S)-10-(tert-butyldimethylsilanyloxy)-4-methoxy-8-triisopropylsilanyloxymethyl-1,7-dioxaspiro[5.5]undec-2-yl]-butan-2-one

[(2R,4S,6S,8S,10S)-4-(tert-Butyl-dimethyl-silanyloxy)-10-hydroxy-10-methyl-8-(2-triethylsilanyloxy-ethyl)-1,7-dioxa-spiro[5.5]undec-2-yl]-acetaldehyde

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

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