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