(2S,3R,6S,8R,9S)-3-Butyl-3-(tert-butyl-dimethyl-silanyloxy)-8-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-2-ethynyl-9-methyl-1,7-dioxa-spiro[5.5]undecane

{(2S,3R,6S,8R,9S)-3-Butyl-3-(tert-butyl-dimethyl-silanyloxy)-8-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-9-methyl-1,7-dioxa-spiro[5.5]undec-2-yl}-methanol