Chinese Journal of Natural Medicines (English Ed.) 2020;18(10):723-728

doi:10.1016/S1875-5364(20)60012-7

Anomeric configuration-dependence of the Lattrell-Dax epimerization from D-glucose to synthetically useful D-allose derivatives.

Yun-Zhan NING 1 ; Chun-Jun QIN 1 ; Wen-Bin SUN 1 ; Jun-Jie FU 1 ; Jing HU 2 ; Jian YIN 3

Affiliations

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Keywords

Acyl migration; Anomeric configuration; D-allosamine; D-allose; Epimerization

Country

China

Language

English

Abstract

D-Allose and its derivatives play important roles in the field of health care and food nutrition. Pure and well-defined D-allose derivatives can facilitate the elucidation of their structure-activity relationship as an essential step for drug design. The Lattrell-Dax epimerization, refers to the triflate inversion using nitrite reagent, is known as valuable method for the synthesis of rare D-allose derivatives. Here, the influence of protecting group patterns on the transformation efficiency of D-glucose derivatives into synthetically useful D-alloses and D-allosamines via the Lattrell-Dax epimerization was studied. For C3 epimerization of D-glucose derivatives bearing O2-acyl group, an anomeric configuration-dependent acyl migration from O2 to O3 was found. In addition, a neighbouring group participation effect-mediated S1 nucleophilic substitution of the D-glucosamine bearing C2 trichloroacetamido (TCA) group in the Lattrell-Dax epimerization was dependent upon anomeric configuration. Thus, the effect of anomeric configuration on the Lattrell-Dax epimerization of D-glucose suggests that β-D-glucosides with low steric hindrance at C2 should be better substrates for the synthesis of D-allose derivatives. Significantly, the efficient synthesis of the orthogonally protected D-allose 13 and D-allosamine 18 will serve well for further assembly of complex glycans.