(6R,8R,10R)-8-benzyloxymethyl-10-(tert-butyl-dimethyl-silanyloxy)-2-(2-hydroxy-butyl)-1,7-dioxa-spiro[5.5]undec-2-en-4-one

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