2,2-dimethyl-propionic acid-(2R,4S,6R)-4-(tert-butyl-dimethyl-silanyloxy)-8-(2-hydroxy-butyl)-10-oxo-1,7-dioxa-spiro[5,5]undec-8-en-2-ylmethyl ester

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