β-l-Rhamnosylation and β-d-Mannosylation Mediated by 4- O-Ester Groups in a Weakly Nucleophilic Environment

Yongliang Zhang; Changsheng Chen; Yongtao Gao; Min Yang; Zehuan He; Bangzhi Zhang; Guofeng Gu; Bencan Tang; Feng Cai

doi:10.1021/acs.orglett.3c02566

β-l-Rhamnosylation and β-d-Mannosylation Mediated by 4- O-Ester Groups in a Weakly Nucleophilic Environment

Org Lett. 2023 Oct 6;25(39):7120-7125. doi: 10.1021/acs.orglett.3c02566. Epub 2023 Sep 22.

Authors

Yongliang Zhang¹, Changsheng Chen¹, Yongtao Gao¹, Min Yang², Zehuan He¹, Bangzhi Zhang³, Guofeng Gu¹, Bencan Tang⁴, Feng Cai^{1

3}

Affiliations

¹ National Glycoengineering Research Center and Shandong Key laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 72 Binhai Rd Qingdao 266237, China.
² Center for Analysis and Characterization, School of Physical Science and Technology, ShanghaiTech University, 393 Huaxia Middle Rd, Shanghai 201210, China.
³ Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, China.
⁴ Faculty of Science and Engineering, The University of Nottingham Ningbo China, 199 Taikang E Rd, Ningbo 315100, China.

PMID: 37738091
DOI: 10.1021/acs.orglett.3c02566

Abstract

eq-4-O-Acyl group directed β-rhamnosylation and β-mannosylation are achieved in a carborane or BARF anion formed weakly nucleophilic environment with the assistance of a 2,3-orthocarbonate group. The 4-O-acyl group plays a critical role in directing the β-selectivity, and the weakly coordinating anion is essential to amplify this direction. The orthocarbonate group could be readily removed with 1,3-propanediol in the presence of BF₃·Et₂O.