2,2-dimethyl-propionic acid-(2R,4S,6S,8R,10S)-8-(2-acetoxy-butyl)-4-hydroxy-10-methoxy-1,7-dioxa-spiro[5.5]undec-2-ylmethyl ester

2,2-dimethyl-propionic acid-(2R,4R,6R,8R,10S)-8-(2-acetoxy-butyl)-4-(tert-butyl-dimethyl-silanyloxy)-10-methoxy-1,7-dioxa-spiro[5.5]undec-2-ylmethyl ester

2,2-dimethy-propionic acid-(2R,4R,6R,8S,10S)-8-(2-acetoxy-buty)-4-(tert-butyl-dimethyl-silanyloxy)-10-hydroxy-1,7-dioxa-spiro[5.5]undec-2-ylmethyl ester

2,2-dimethyl-propionic acid-(2R,4R,6S,8R)-4-(tert-butyl-dimethyl-silanyloxy)-8-(2-hydroxy-butyl)-10-oxo-1,7-dioxa-spiro[5.5]undec-2-ylmethyl ester

2,2-dimethyl-propionic acid (2R,4R,6S,8R)-8-(2-acetoxy-butyl)-4-(tert-butyl-dimethyl-silanyloxy)-10-oxo-1,7-dioxa-spiro[5.5]undec-2-ylmethyl ester

2-[(4R)-5-benzyloxy-2-(tert-butyl-dimethyl-silanyloxy)-4-(4-methoxy-benzyloxy)-pentyl]-6-methyl-pyran-4-one

2,2-dimethyl-propionic acid-(2R,6R,8R,10S)-8-(2-acetoxy-butyl)-10-methoxy-4-oxo-1,7-dioxa-spiro[5.5]undec-2-ylmethyl ester