Cesium carbonate-mediated anomeric O-alkylation of various protected 2-azido-2-deoxy-d-mannoses with primary triflate electrophiles afforded corresponding 2-azido-2-deoxy-β-mannosides in good yields and excellent anomeric selectivity. In addition, 1,3-dibromo-5,5-dimethylhydantoin was found to be the optimal oxidant for preparation of those 2-azido-2-deoxy-d-mannoses from their corresponding thioglycosides. The utilization of this method was demonstrated in the synthesis of a tetrasaccharide fragment of Micrococcus luteus teichuronic acid containing N-acetyl-β-d-mannosaminuronic acid (ManNAcA).
Bishwa Raj Bhetuwal, Fenglang Wu, Shuai Meng, Jianglong Zhu. Stereoselective Synthesis of 2-Azido-2-deoxy-β-d-mannosides via Cs2CO3-Mediated Anomeric O-Alkylation with Primary Triflates: Synthesis of a Tetrasaccharide Fragment of Micrococcus luteus Teichuronic Acid. The Journal of organic chemistry. 2020 Dec 18;85(24):16196-16206
PMID: 33201716
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