2,3,4,6,7-penta-O-acetyl-L-glycero-α-D-manno-heptopyranosyl trichloroacetimidate 、
methyl (allyl 7,8-O-carbonyl-3-deoxy-α-D-manno-2-octulopyranosid)-onate 在
三氟甲磺酸三甲基硅酯 、 4 A molecular sieve 作用下,
以
二氯甲烷 为溶剂,
以61%的产率得到methyl (2R,4R,5R,6S)-5-hydroxy-6-[(4R)-2-oxo-1,3-dioxolan-4-yl]-2-prop-2-enoxy-4-[(2S,3S,4S,5R,6R)-3,4,5-triacetyloxy-6-[(1S)-1,2-diacetyloxyethyl]oxan-2-yl]oxyoxane-2-carboxylate