1-{6-[6-(6-allyloxy-2,2-dimethyl-tetrahydro-furo[2,3-d][1,3]dioxol-5-ylmethoxy)-2,2-dimethyl-tetrahydro-furo[2,3-d][1,3]dioxol-5-ylmethoxy]-2,2-dimethyl-tetrahydro-furo[2,3-d][1,3]dioxol-5-yl}-ethane-1,2-diol