Effect of Remote Picolinyl and Picoloyl Substituents on the Stereoselectivity of Chemical Glycosylation
摘要:
O-Picolinyl and O-picoloyl groups at remote positions (C-3, C-4, and C-6) can mediate glycosylation reactions by providing high or even complete facial selectivity for the attack of the glycosyl acceptor. The set of data presented herein offers a strong evidence of the intermolecular H-bond tethering between the glycosyl donor and glycosyl acceptor counterparts while providing a practical new methodology for the synthesis of either 1,2-cis or 1,2-trans linkages. Challenging glycosidic linkages including alpha-gluco, beta-manno, and beta-rhamno have seen obtained with high or complete stereocontrol.
Hydrogen bond activated glycosylation under mild conditions
作者:Ke Xiao、Yongxin Hu、Yongyong Wan、XinXin Li、Qin Nie、Hao Yan、Liming Wang、Jinxi Liao、Deyong Liu、Yuanhong Tu、Jiansong Sun、Jeroen D. C. Codée、Qingju Zhang
DOI:10.1039/d1sc05772c
日期:——
Benefitting from the mild reaction conditions, this new hydrogen bond-mediated glycosylation system in combination with a hydrogen bond-mediated aglycon delivery system provides a reliable method for the synthesis of challenging phenolic glycosides. In addition, a chemoselective glycosylation procedure was developed using different imidate donors (trichloroacetimidates, N-phenyl trifluoroacetimidates, N-4-nitrophenyl