Unexpected anomeric selectivity of a 1-C-arylglycal donor in Kdo glycoside synthesis
Yuxin Qian1, Jianhao Feng, Masood Parvez
1Alberta Ingenuity Centre for Carbohydrate Science, Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T3G 3M9, Canada.
Abstract:
A novel class of 1-C-arylglycals was developed and subjected to N-iodosuccinimide-mediated glycosylations with alcohols. Unexpectedly, all reactions provided 2-iodo-β-D-ketopyranosides in high yields and excellent stereoselectivity. After removal of the 2-iodide by radical conditions, the aryl group was smoothly oxidized to provide the corresponding β-Kdo glycosides. A mechanism for the stereoselective formation of β-D-ketopyranosides was proposed, which was supported by evidence from X-ray crystallography.
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