methyl-3,4-di-O-benzyl-α-L-rhamnopyranoside   、                                                                                      
L(+)-rhamnose                                                                                                                                                              在
                                                                                                                                                                                 4 A molecular sieve   、                                                                                                  TMSPTf                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
乙醚                                                                                  为溶剂,
                                                                                                                                                    反应 4.0h,
                                                                                                                以67%的产率得到Acetic acid (2S,3R,4R,5S,6S)-4,5-bis-benzyloxy-2-((2R,3R,4R,5S,6S)-4,5-bis-benzyloxy-2-methoxy-6-methyl-tetrahydro-pyran-3-yloxy)-6-methyl-tetrahydro-pyran-3-yl ester