作者:Peter Stoss、Peter Merrath、Günther Schlüter
DOI:10.1055/s-1987-27878
日期:——
Regioselective Acylation of 1,4:3,6-Dianhydro-D-glucitol Acylation of 1,4:3,6-dianhydro-D-glucitol with anhydrides in the presence of heavy metal salts affords 5-endo-acylates with high regioselectivity, without detectable amounts of the isomeric 2-acylates. Acyl group migration occurs with preference for the 2-exo-position, on heating an acylation mixture, which contains varying amounts of 1,4:3,6-dianhydro-D-glucitol, 2- and 5-monoacylate and 2,5-diacylate, in the presence of reesterification catalysts and whilst distilling off the lower boiling 2-acylate.
1,4:3,6-二脱氢-D-葡萄糖醇的区域选择性酰化 1,4:3,6-二脱氢-D-葡萄糖醇在重金属盐存在下与酸酐发生酰化反应,可生成具有高区域选择性的 5-内向酰化物,且检测不到大量异构的 2-酰化物。在有酯化催化剂存在的情况下,加热含有不同量的 1,4:3,6-二脱氢-D-葡萄糖醇、2-和 5-单乙酸酯以及 2,5-二乙酸酯的酰化混合物,同时蒸馏掉沸点较低的 2-乙酸酯,就会发生酰基迁移,优先选择 2-外位。