Synthesis of chiral auxiliary and multi-activation ligand having phosphonylated sugar moiety and their application for asymmetric synthesis

甲基4，6-di-O-acetyl-2，3-dideoxy-D-erythro-hex-2-enopyranoside与两个当量的二苯基膦阳离子在0°C反应，主要产物为α-和β-1-膦酰化2-吡喃糖苷。同样，二苯基膦阳离子与三-O-乙酰基乙二醛的反应以相似的比例得到相同的产物。相反，在二氯甲烷的回流温度下与三-O-苄基葡萄糖醛反应，得到的主要产物是3-膦酰化的糖。这些反应将通过稳定的烯丙基阳离子进行。此外，3-膦酰化的糖还可以作为手性助剂。例如，3-磷酰化糖的丙烯酸酯与环戊二烯的Diels-Alder反应得到了产率很高的环加合物，具有很好的非对映选择性。

Reaction of methyl 4,6-di-O-acetyl-2,3-dideoxy-D-erythro-hex-2-enopyranoside with two equivalents of diphenylphosphenium cation at 0° C gave the α-and β-1-phosphonylated 2-enopyranosides as major products. Similarly, Reaction of diphenylphosphenium cation with tri-O-acetylglycal afforded the same products in a similar ratio. By contrast, a reaction with tri-O-benzylglucal at reflux temperature of dichloromethane afforded the 3-phosphonylated sugar as a major product. These reactions would proceed via stable allyl cations. Furthermore, the 3-phosphonylated sugar was useful for chiral auxiliary. For example, Diels-Alder reaction of an acrylate ester of the 3-phosphonylated sugar with eyclopentadiene gave a cycloadduct in good yield with excellent diastereoselectiviry.