Perfluoroalkylation of Aryl-<i>N</i>,<i>N</i>-dimethyl Hydrazones Using Hypervalent Iodine(III) Reagents or Perfluoroalkyl Iodides
作者:Benjamin Janhsen、Armido Studer
DOI:10.1021/acs.joc.7b00934
日期:2017.11.17
Radical trifluoromethylation of aryl N,N-dimethyl hydrazones using TBAI as an initiator and Togni’s reagent as a trifluoromethyl radical source is described. Cascades proceed via electron-catalysis; this approach is generally more applicable to hydrazone perfluoroalkylation using perfluoroalkyl iodides as the radical precursors in combination with a base under visible-light initiation.
The synthesis of N-alkyl-1H-1,2,4-triazoles from N,N-dialkylhydrazones and nitriles via formal [3+2] cycloaddition including the C-chlorination/nucleophilic addition/cyclisation/dealkylation sequence was developed. This sequential reaction utilising the in situ generation of hydrazonoyl chloride based on the ambiphilic reactivity of hydrazones afforded a variety of multi-substituted N-alkyl-triazoles
Gold-Catalyzed Highly Selective Photoredox C(sp<sup>2</sup>
)−H Difluoroalkylation and Perfluoroalkylation of Hydrazones
作者:Jin Xie、Tuo Zhang、Fei Chen、Nina Mehrkens、Frank Rominger、Matthias Rudolph、A. Stephen K. Hashmi
DOI:10.1002/anie.201508622
日期:2016.2.18
hydrazones are highly functionalized, versatile molecules. A mild reduction of the coupling products can efficiently produce gem‐difluoromethylated β‐amino phosphonic acids and β‐amino acid derivatives. In mechanistic studies, a difluoroalkyl radical intermediate was detected by an EPR spin‐trappingexperiment, indicating that a gold‐catalyzed radical pathway is operating.
据报道,使用容易获得的R F -Br试剂,gold的金催化光氧化还原C(sp 2)-H二氟烷基化和hydr的全氟烷基化。所得的宝石二氟甲基化和全氟烷基化的azo是高度官能化的多用途分子。偶合产物的轻度减少可以有效地生产出宝石-二氟甲基化的β-氨基膦酸和β-氨基酸衍生物。在机理研究中,通过EPR自旋捕获实验检测到二氟烷基自由基中间体,表明金催化的自由基途径正在起作用。
C–H Difluoroalkylation of Aldehyde Hydrazones with Functionalized Difluoromethyl Bromides under Copper Catalysis
The Cu-catalyzed direct difluoroalkylation of aldehyde hydrazones with functionalized difluoromethyl bromides is described. The reaction yields stereodefined α,α–difluoro-β-keto hydrazones under mild conditions and can be carried out at a scale that opens up the possibility of practical applications.
A facile and convenient synthesis of 5-trifluoromethyl-4-pyridazinones from aldehyde dialkylhydrazones
作者:Yasuhiro Kamitori、Masaru Hojo、Ryoichi Masuda、Toshiaki Ikemura、Yoshiko Mori
DOI:10.1016/s0040-4039(00)60696-2
日期:1993.8
Several 5-trifluoromethyl-4-pyridazinones were conveniently synthesized by silica gel-mediated cyclization reaction of 1,1,1,2,2-pentafluoroalkan-3,4-dione 4-dialkylhydrazones prepared fromaldehyde dialkylhydrazones and pentafluoropropionic anhydride.