Trifluoro-methanesulfonic acid (1R,3R,3aS,6S,6aR)-6-(tert-butyl-diphenyl-silanyloxymethyl)-3-isopropyl-3-methoxy-3a-methyl-4-oxo-tetrahydro-furo[3,4-c]furan-1-ylmethyl ester

(3S,3aR,4S,6R,6aS)-3-(((tert-butyldiphenylsilyl)oxy)methyl)-4-(((R)-5-ethyl-2-methyl-3-oxo-2,3-dihydrofuran-2-yl)methyl)-6-isopropyl-6-methoxy-6a-methyltetrahydrofuro[3,4-c]furan-1(3H)-one