inversion of configuration, probably through an episulphonium-ion intermediate, to give the diethyl dithioacetal (2) of 2-S-ethyl-2-thio-D-mannose (9), the free sugar (9) being exceptionally readily epimerized, at pH 8, to give the gluco-analogue (8).
酸催化的3,4,5,6-四-O-苯甲酰基-
D-葡萄糖二乙基二
硫缩醛(1)中C-2羟基被乙
硫基取代的过程可能会发生构型反转上磺砜离子中间体,得到2- S-乙基-2-
硫代
D-甘露糖的
二乙基二
硫缩醛(2)(9),游离糖(9)在pH 8时特别容易差向异构化,得到
葡萄糖-模拟(8)。