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
Use of Hemilabile N,N Ligands in Nitrogen-Directed Iridium-Catalyzed Borylations of Arenes
作者:Abel Ros、Beatriz Estepa、Rocío López-Rodríguez、Eleuterio Álvarez、Rosario Fernández、José M. Lassaletta
DOI:10.1002/anie.201104544
日期:2011.12.2
The hemilabile character of 2‐pyridyl carbaldehyde hydrazones as N,N bidentate ligands is key to performing regioselective IrIII‐catalyzed ortho borylations of 2‐aryl pyridines(isoquinolines) and aromatic N,N‐dimethylhydrazones (see scheme; pin=pinacol, Bn=benzyl). Internal “ate” complexes or products free from NB interactions are formed depending on the steric properties of the substrates.
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.