金催化立体选择性构建β艾杜七碳糖苷键

Gold(I)-Catalyzed Stereoselective Construction ofβ-idosidic Bond

本文发展了一种简洁高效的金催化立体选择性构建β-艾杜七碳糖苷键的方法。以全苄基保护的艾杜七碳糖邻己炔基苯甲酸酯3作为供体,6-OH裸露的苄基葡萄糖甲苷4作为受体,以多种金催化剂进行糖苷化反应,最终确定以(PhO)_3PAuCl和AgB(C_6F_5)_4为最优催化体系,以96%的收率和β/α=7∶1的立体选择性构建了β-艾杜七碳糖苷键。在最优条件下以邻己炔基苯甲酸酯供体3与氨基糖衍生物6进行糖苷化反应,以77%的收率和β/α=2∶1的立体选择性完成了二糖化合物7的合成。

A convenient and effective protocol for construction ofβ-idosidic bond was developed.With the 2,3,4,7-Tetra-O-benzyl-1-(ortho-hexynylbenzoate)-α-D-idopyranoside 3 as glycosyl donor and the 2,3,4-Tri-O-benzyl-1-methyl-α-D-glucopyranoside 4 as glycosyl acceptor,the selectivity was investigated in different conditions in which a series of Gold(I)catalysts were used and(PhO)3PAuCl/AgB(C 6F 5)4 was finally determined as the optimal catalytic system with the stereoselectivity up toβ/α=7∶1 and the yield of 96%.Under the optimal condition,glycosyl donor 3 and amino sugar derivative 6 were coupled to afford the disaccharide 7 with the stereoselectivityβ/α=2∶1 and the yield of 77%.