Selective Palladium‐Catalyzed Direct CH Arylation of Unsubstituted
<i>N</i>
‐Protected Pyrazoles
作者:Esa T. T. Kumpulainen、Antti Pohjakallio
DOI:10.1002/adsc.201301139
日期:2014.5.5
selective C‐5 arylation of N‐dimethylaminosulfamoyl‐protected pyrazole with aryl bromides is catalyzed by 2–5 mol% palladium in the presence of triphenylphosphine ligand and carboxylic acid additive. Selectivities up to 45:1 (C‐5:C‐4) can be achieved by running the reaction in non‐polar solvents. A thorough study of scope and limitations shows good general tolerance of aryl bromide substitution. However