Synthesis of rapamycin glycoconjugates via a CuAAC-based approach
摘要:
The conversion of the C40 secondary hydroxyl group of rapamycin into the azido group was followed by copper catalyzed cycloaddition of the resulting azido-rapamcin with various unprotected propargyl O-and S-glycosides and a C-ethynyl derivative. This approach furnished a collection of triazole-bridged rapamycin glycoconjugates (14 examples) in 44-83% isolated yield. (C) 2013 Elsevier Ltd. All rights reserved.
Palladium-Mediated Oxidative Homocoupling of Prop-2-ynyl Glycosides: Application Toward the Synthesis of Symmetrical Conjugated Sugar Diynes
作者:René Roy、Sanjoy Kumar Das、Fernando Hernández-Mateo、Francisco Santoyo-González、Zhonghong Gan
DOI:10.1055/s-2001-14903
日期:——
A palladium-catalyzed reaction has been applied toward the synthesis of divalent carbohydrate derivatives, which showed excellent lectin cross-linking abilities. The procedure, which involves copper(I) iodide and dichlorobis(triphenylphosphine)palladium(II)-catalyzed head-to-head coupling of prop-2-ynyl glycosides, is very efficient affording symmetrically conjugated carbohydrates containing 1,3-diynes in excellent yields. The reactions proceeded rapidly and efficiently at room temperature without the need for added oxidizing agents.