(S)-benzyl 2-(benzyloxycarbonyl)but-3-enoate   、                                                                                      allyl 2,3,4,6-tetra-O-acetyl-α-D-galactopyranoside                                                                                                                                                              在
                                                                                                                                         tri(cycloxexyl)phosphine[1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidene]ruthenium(IV) dichloride                                                                                                                                                                          作用下,
                                                                                                                以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                    反应 48.0h,
                                                                                                                以98%的产率得到benzyl (2S)-5-(2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl)-2-(benzyloxycarbonylamino)pent-3-enoate