A regioselectivity switch in Pd-catalyzed hydroallylation of alkynes
作者:Ding-Wei Ji、Yan-Cheng Hu、Hao Zheng、Chao-Yang Zhao、Qing-An Chen、Vy M. Dong
DOI:10.1039/c9sc01527b
日期:——
Through rational evaluation of ligands and promoters, the reactivity of a key Pd(ii) species towards transmetalation or β-H elimination is manipulated.
of sulfonyl radicals to alkenes and alkynes is a valuable method for constructing useful highly functionalized sulfonyl compounds. The underexplored alkoxy- and fluorosulfonyl radicals are easily accessed by CF3 radical addition to readily available allylsulfonic acid derivatives and then β-fragmentation. These substituted sulfonyl radicals add to aryl alkyl alkynes to give vinyl radicals that are trapped
Three-Component Friedel–Crafts Transformations: Synthesis of Alkyl and Alkenyl Trifluoromethyl Sulfides and Alkenyl Iodides
作者:Duc Chu、Jonathan A. Ellman
DOI:10.1021/acs.orglett.2c00924
日期:2022.4.22
and alkyl trifluoromethyl sulfides from arenes, (PhSO2)2NSCF3, and alkynes or alkenes, respectively. The transformations proceed with high regio- and stereochemical control via the initial formation of cationic thiirenium and thiiranium intermediates, respectively, followed by Friedel–Crafts reactions with the arene. A mechanistically related three-component synthesis of alkenyl iodides from arenes
A novel regio- and stereoselective reductive coupling of vinyl azaarenes and alkynes has been developed to access functionalized azaarene compounds bearing stereodefined tri-substituted alkenes via photoredox cobalt dualcatalysis. Simple organic base together with alcohol has been applied as the hydrogen sources instead of commonly used Hantzsch esters in this coupling reaction.
Regio- and Stereoselective Reductive Coupling of Alkynes and Crotononitrile
作者:Kun Cui、Yan-Lin Li、Gongqiang Li、Ji-Bao Xia
DOI:10.1021/jacs.2c10021
日期:2022.12.21
bearing a stereodefinedtrisubstitutedalkene have been easily synthesized with good to excellent regio- (up to >20:1 rr), stereo- (>20:1 E/Z), and enantioselectivity (up to 98% ee) control under mild conditions. The corresponding nitrile products were smoothly converted into various chiral building blocks. Remarkably, a simple organic base together with water have been utilized as hydrogen sources in this
通过可见光有机光氧化还原钴双催化开发了炔烃和巴豆腈的新区域选择性和立体选择性还原偶联。多种带有立构定义的三取代烯烃的对映体富集的同烯丙基腈很容易合成,具有良好到极好的区域-(高达 >20:1 rr)、立体-(>20:1 E / Z)和对映选择性(高达 98% ee) 在温和条件下控制。相应的腈产物顺利转化为各种手性结构单元。值得注意的是,在这种光诱导还原反应中,一种简单的有机碱与水一起被用作氢源。