Preparation of rare L-idose derivatives from D-glucofuranose via neighboring acyl group assistance

An efficient protocol for preparation of rare L-idose derivatives from 5-OH D-glucofuranose derivatives was developed, and the stereo-inversion of 5-OH was assisted by neighboring acyl group. A library of L-idose derivatives with various protective groups at C3 and C6 positions were obtained from the corresponding D-glucofuranose derivatives in good to high yields, which provides an alternative approach for the synthesis of L-iduronic acid building blocks when assembling heparin-like oligosaccharides. And the mechanism of the stereo-inversion reaction was proposed.