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
journal contributionposted on 17.11.2020, 21:44 by Bishwa Raj Bhetuwal, Fenglang Wu, Shuai Meng, Jianglong Zhu
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).