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.
Copper-Catalyzed Double C–H Alkylation of Aldehyde-Derived <i>N</i>,<i>N</i>-Dialkylhydrazones with Polyhalomethanes: Flexible Access to 4-Functionalized Pyrazoles
作者:Alexis Prieto、Didier Bouyssi、Nuno Monteiro
DOI:10.1021/acscatal.6b02439
日期:2016.10.7
have been made accessible in a single step from readily available aldehyde-derived N,N-dialkyl hydrazones and functionalized polyhalomethane derivatives. The process is believed to follow copper-catalyzed cascade C(sp2)–H haloalkylation/C(sp3)–H cyclization/aromatization reaction sequences.
The electrochemical thiocyanation/cyclization of aldehyde hydrazones was developed under external oxidant‐free and catalyst‐free conditions. In contrast to previous thiocyanation, this electrosynthetic approach enabled a cascade C—H thiocyanation/cyclization through a mild, direct electrolysis manner in an undivided cell without the additive of halogens and stoichiometric oxidants. In this protocol
An ammonium persulfate mediated thiocyanation reaction of aldehyde‐derived hydrazones that affords 5‐thioxo‐1,2,4‐triazoliuminnersalts has been developed. The operational simplicity, mild and metal‐free reaction conditions performed at ambient temperature, wide functional group tolerance, and scalability of the process are key features of this method.
Phenyliodonium diacetate mediated carbotrifluoromethylation of N-acylhydrazones
作者:Weigang Zhang、Yingpeng Su、Siying Chong、Lili Wu、Guiyan Cao、Danfeng Huang、Ke-Hu Wang、Yulai Hu
DOI:10.1039/c6ob02041k
日期:——
A concise, efficient and direct trifluoromethylation method of aldehyde-derived N-acylhydrazones has been firstly developed by using the combination of inexpensive, stable and commercially available TMSCF3 and PhI(OAc)2 as the CF3 source under mild reaction conditions. This method provides easy access to highly functionalized trifluoromethylated N-acylhydrazones, which could be used as trifluoromethyl