Triple Role of Proton Sponge (DMAN) in the Palladium-Catalyzed Direct Stereoselective Synthesis of <i>C</i>-Aryl Glycosides from Glycals
作者:Priyanka Pradhan、Sangay Moktan、Ashish Biswas、Animesh Das、Rajesh Lenka、Pavan K. Kancharla
DOI:10.1021/acs.orglett.4c00997
日期:——
sponge) as a reductant, ligand precursor, and organic base in the palladium-catalyzed Heck-type coupling reaction of glycals with aryl iodides affords the rapid and stereoselective synthesis of 2′,3′-unsaturated α-C-aryl glycosides in excellent yields. The role of the proton sponge in reducing palladium(II) to (0) has been studied using cyclic voltammetry, UV–vis, HRMS, and other spectroscopic techniques
1,8-双(二甲氨基)萘(质子海绵)作为还原剂、配体前体和有机碱,在钯催化的甘醛与芳基碘化物的 Heck 型偶联反应中发挥三重作用,可快速、立体选择性地合成 2 ',3'-不饱和α- C-芳基糖苷的产率极佳。使用循环伏安法、紫外可见分光光度计、HRMS 和其他光谱技术研究了质子海绵将钯 (II) 还原为 (0) 的作用。这是用于偶联反应的钯质子海绵络合物的第一个例子。观察到该方法对各种官能团具有耐受性,巨大的底物范围证明了这一点。此外,在位阻吡啶鎓盐催化下,2',3'-不饱和α- C-芳基糖苷也通过开环和闭环机制转化为3-酮-β- C-糖苷。