A New and Mild System for the Generation of Nonstabilized Carbonyl Ylides: Synthetically Practical Use in Reactions with Electron-Deficient Dipolarophiles
Reductive Cyclopropanations Catalyzed by Dinuclear Nickel Complexes
作者:You-Yun Zhou、Christopher Uyeda
DOI:10.1002/anie.201511271
日期:2016.2.24
Dinuclear Ni complexes supported by naphthyridine‐diimine (NDI) ligands catalyze the reductive cyclopropanation of alkenes with CH2Cl2 as the methylene source. The use of mild terminal reductants (Zn or Et2Zn) confers significant functional‐group tolerance, and the catalyst accommodates structurally and electronically diverse alkenes. Mononickel catalysts bearing related N chelates afford comparatively
Reactions on a Solid Surface. A Simple, Economical, and Efficient Acylation of Alcohols and Amines over Al<sub>2</sub>O<sub>3</sub>
作者:Veejendra K. Yadav、K. Ganesh Babu
DOI:10.1021/jo035412f
日期:2004.1.1
Al2O3 brings about a rapid acylation of a range of alcohols and amines with acid chlorides and acid anhydrides, respectively. Amines are easily Boc- and Cbz-protected on reaction with Boc-anhydride and Cbz-Cl, respectively. The acylation of phenols is slow enough to allow chemoselective acylation of alcohols and amines in the presence of phenols.
Al 2 O 3分别使多种醇和胺分别与酰氯和酸酐快速酰化。分别与Boc酸酐和Cbz-Cl反应时,胺很容易受到Boc和Cbz保护。酚的酰化足够慢,以允许在酚存在下醇和胺的化学选择性酰化。
Efficient Cu-catalyzed Atom Transfer Radical Addition Reactions of Fluoroalkylsulfonyl Chlorides with Electron-deficient Alkenes Induced by Visible Light
作者:Xiao-Jun Tang、William R. Dolbier
DOI:10.1002/anie.201412199
日期:2015.3.27
Fluoroalkylsulfonyl chlorides, RfSO2Cl, in which Rf=CF3, C4F9, CF2H, CH2F, and CH2CF3, are used as a source of fluorinated radicals to add fluoroalkyl groups to electron‐deficient, unsaturated carbonyl compounds. Photochemical conditions, using Cu mediation, are used to produce the respective α‐chloro‐β‐fluoroalkylcarbonyl products in excellent yields through an atom transferradicaladdition (ATRA) process
氟烷基磺酰氯,R f SO 2 Cl,其中R f= CF 3,C 4 F 9,CF 2 H,CH 2 F和CH 2 CF 3,被用作氟自由基的来源以向电子中添加氟烷基。不足的不饱和羰基化合物。通过铜介导的光化学条件,可通过原子转移自由基加成(ATRA)工艺以优异的产率生产相应的α-氯-β-氟代烷基羰基产物。α-氯取代基的容易亲核取代会导致产物进一步多样化的功能。
Acid- and Base-Switched Palladium-Catalyzed γ-C(sp<sup>3</sup>)–H Alkylation and Alkenylation of Neopentylamine
作者:Jinquan Zhang、Shuaizhong Zhang、Hongbin Zou
DOI:10.1021/acs.orglett.1c00903
日期:2021.5.7
unactivated C(sp3)–H and the reaction selectivity are among the core pursuits for transition-metal catalytic system development. Herein, we report Pd-catalyzed γ-C(sp3)–H-selective alkylation and alkenylation with removable 7-azaindole as a directing group. Acid and base were found to be the decisive regulators for the selective alkylation and alkenylation, respectively, on the same single substrate under otherwise
Direct Photoredox‐Catalyzed Reductive Difluoromethylation of Electron‐Deficient Alkenes
作者:Xiao‐Jun Tang、Zuxiao Zhang、William R. Dolbier
DOI:10.1002/chem.201504363
日期:2015.12.21
Photoredox‐catalyzed reductivedifluoromethylation of electron‐deficient alkenes was achieved in one step under tin‐free, mild and neutral conditions. This protocol affords a facile method to introduce RCF2 (R=H, Ph, Me, and CH2N3) groups at sites β to electron‐withdrawing groups. It was found that TTMS (tris(trimethylsilyl)silane) served nicely as both the H‐atom donor and the electron donor in the
在缺锡,温和和中性的条件下,一步一步就可以完成缺氧烯烃的光氧化还原催化的还原性二氟甲基化反应。该方案提供了一种简便的方法,可将β位的RCF 2(R = H,Ph,Me和CH 2 N 3)基团引入吸电子基团。发现TTMS(三(三甲基甲硅烷基)硅烷)在催化循环中既可以作为氢原子供体,也可以作为电子供体。实验和DFT计算结果提供了RCF 2(R = H,Ph,Me)自由基本质上亲核的证据。