Stereoselective Synthesis of 2‐Deoxyglycosides from Glycals by Visible‐Light‐Induced Photoacid Catalysis
作者:Gaoyuan Zhao、Ting Wang
DOI:10.1002/anie.201800909
日期:2018.5.22
The direct, photoacid‐catalyzed synthesis of 2‐deoxyglycosides fromglycals is reported. A series of phenol‐conjugated acridinium‐based organic photoacids were rationally designed, synthesized, and studied alongside the commercially available phenolic catalyst eosin Y. In the presence of such a photoacid catalyst and light, synthetic glycals were activated and coupled with a range of alcohols to afford
cascade amidoglycosylation was initiated by a benzenesulfonimide radical generated from NFSI under the catalytic reduction of TEMPO. The benzenesulfonimide radical was electrophilically added to the glycals, and then the resulting glycosidic radical was converted to oxocarbenium upon oxidation by TEMPO+, which enabled the following anomeric specific glycosylation.
建立了一种以氮为中心的自由基介导的一步制备1,2-反式-2-氨基-2-脱氧糖苷的策略。级联酰胺糖基化由 NFSI 在 TEMPO 催化还原下产生的苯磺酰亚胺自由基引发。苯磺酰亚胺自由基亲电加成到糖基上,然后得到的糖苷自由基在被 TEMPO +氧化后转化为氧代碳鎓,这使得以下异头特异性糖基化成为可能。
Ir(I)‐Catalyzed C−H Glycosylation for Synthesis of 2‐Indolyl‐
<i>C</i>
‐Deoxyglycosides
作者:Changyue Yu、Yichu Liu、Xiong Xie、Shulei Hu、Shurui Zhang、Mingjie Zeng、Dan Zhang、Jiang Wang、Hong Liu
DOI:10.1002/adsc.202100855
日期:2021.11.9
we present an efficient, regioselective, stereoselective and widely applicable strategy for the synthesis of 2-indolyl-C-deoxyglycosides via Ir(I)-catalyzed, pyridine-group-directed C−H functionalization. This method exhibits high tolerance for the functional groups of indoles and the protecting groups of carbohydrates. Moreover, this protocol has good stereoselectivity and mainly produces β-configuration
catalyzed direct functionalization of dihydropyrans and glycals has been developed. This method affords a new and straightforward access to C-2-CF2 dihydropyrans and glycosides in a single step starting from readily available starting materials. This new copper based catalytic system, probably involving a Cu(III) species as supported by experiments, allows the formation of the valuable fluorinated glycosides
Synthesis and Absolute Stereochemistry of Roseophilin
作者:Paul E. Harrington、Marcus A. Tius
DOI:10.1021/ja011242h
日期:2001.9.1
The enantiospecific total synthesis of natural roseophilin has been completed in 7.0% overall yield over 15 steps by means of an asymmetric cyclopentannelation. This establishes the absolute configuration of the natural product as 22R,23R. Cyclopentenone (+)-12 was prepared in 78% yield and 86% ee in the key step.