methyl 3,2':4',6'-di-O-isopropylidene-6-O-(methoxydimethyl)methyl-β-maltoside 生成 [(1R,3R,4R,6R,7R,8S,12R,13S,14R,19R)-7-acetyloxy-6-methoxy-4-(2-methoxypropan-2-yloxymethyl)-10,10,16,16-tetramethyl-2,5,9,11,15,17,20-heptaoxatetracyclo[10.8.0.03,8.014,19]icosan-13-yl] acetate