1020264-31-6Relevant articles and documents
Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a PdII-PdIV-PdII Pathway
Khake, Shrikant M.,Jagtap, Rahul A.,Dangat, Yuvraj B.,Gonnade, Rajesh G.,Vanka, Kumar,Punji, Benudhar
supporting information, p. 875 - 886 (2016/04/19)
Pincer-based (R2POCNR′2)PdCl complexes along with CuI cocatalyst catalyze the arylation of azoles with aryl iodides to give the 2-arylated azole products. Herein, we report an extensive mechanistic investigation for the direct arylation of azoles involving a well-defined and highly efficient (iPr2POCNEt2)PdCl (2a) catalyst, which emphasizes a rare PdII-PdIV-PdII redox catalytic pathway. Kinetic studies and deuterium labeling experiments indicate that the C-H bond cleavage on azoles occurs via two distinct routes in a reversible manner. Controlled reactivity of the catalyst 2a underlines the iodo derivative (iPr2POCNEt2)PdI (3a) to be the resting state of the catalyst. The intermediate species (iPr2POCNEt2)Pd-benzothiazolyl (4a) has been isolated and structurally characterized. A determination of reaction rates of compound 4a with electronically different aryl iodides has revealed the kinetic significance of the oxidative addition of the C(sp2)-X electrophile, aryl iodide, to complex 4a. Furthermore, the reactivity behavior of 4a suggests that the arylation of benzothiazole proceeds via an oxidative addition/reductive elimination pathway involving a (iPr2POCNEt2)PdIV(benzothiazolyl)(Ar)I species, which is strongly supported by DFT calculations.
Direct arylations on water: Synthesis of 2,5-disubstituted oxazoles balsoxin and texaline
Ohnmacht, Stephan A.,Mamone, Patrizia,Culshaw, Andrew J.,Greaney, Michael F.
, p. 1241 - 1243 (2008/12/21)
An efficient two-step palladium catalysed synthesis of 2,5-disubstituted oxazoles is reported. The Royal Society of Chemistry.
