虽然涉及 2e -转移途径的策略决定了糖基化的发展,但由于自由基异头选择性高以及原子和步骤经济性,易于获得的糖基供体作为自由基前体的直接糖基化特别有吸引力。然而,由于常用的不稳定糖基供体的竞争性还原、消除和/或 S N副反应,自由基过程的发展一直充满挑战。在这里,我们介绍了一种有机光催化策略,通过光氧化还原介导的 HAT 催化,糖基溴可以有效地转化为相应的异头自由基,无需过渡金属或导向基团,并实现高度异头选择性。温和的反应条件能够合成具有挑战性的α-1,2-顺式硫代糖苷、各种官能团的耐受性以及常见戊糖和己糖的广泛底物范围,证明了该平台的强大功能。此外,这种通用方法与 sp 2和 sp 3硫亲电子试剂以及总共探测的 50 种底物的后期糖基多样化兼容。
We describe herein a catalyst-free selective C−H sulfenylation of imidazo[1,2-a]pyridines using sulfonothioates as odorless source of thioarylated reagent in an aqueous medium. The method works for a variety of substitutedimidazo[1,2-a]pyridines with broad functional group tolerance. The methodology has been extends to selective sulfernylation of indoles and imidazothiazoles. The sulfonothioates are
practical synthesis of electrophilic sulfenylating reagents, thiosulfonates and disulfides, from inexpensive and easily available sulfonyl chlorides, has been developed. By appropriate choice of solvents, the reaction of sulfonyl chlorides and tetrabutylammonium iodide gave the target products in good to excellent yields, respectively. These transformations probably proceed through a reducing–coupling
Polyfunctional benzylic zinc chlorides by the direct insertion of magnesium into benzylic chlorides in the presence of LiCl and ZnCl2
作者:Albrecht Metzger、Fabian M. Piller、Paul Knochel
DOI:10.1039/b812396a
日期:——
Benzylic zinc chlorides bearing various functional groups are smoothly prepared by the directinsertion of magnesium into benzylic chlorides in the presence of LiCl and ZnCl(2).
Sustainable Three-Component Synthesis of Isothioureas from Isocyanides, Thiosulfonates, and Amines
作者:Pieter Mampuys、Yanping Zhu、Tjøstil Vlaar、Eelco Ruijter、Romano V. A. Orru、Bert U. W. Maes
DOI:10.1002/anie.201406717
日期:2014.11.17
Multiple applications of isothioureas as fine chemicals (or their precursors) are known, but a general sustainable method for their synthesis was hitherto unavailable. We report a novel general approach towards S‐alkyl and S‐aryl isothioureas through a copper(I)‐catalyzed three‐component reaction between amines, isocyanides, and thiosulfonates. The formal synthesis of a superpotent sweetener further
activated dimethylsulfoxide is reported herein. Although the yields of the reactions are moderate, this method enables the incorporation of the SCD3 group of dimethyl sulfoxide-d 6 into thiosulfonates. This is the first synthesis of deuterated thiosulfonates with a labeling purity above 99%. In addition, the cytotoxicity of the thiosulfonates is reported for the first time. thiols - esterification - sulfoxides