| Autor: |
Shishilov, Oleg N., Shamsiev, Ravshan S., Akhmadullina, Nailya S., Flid, Vitaly R. |
| Předmět: |
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| Zdroj: |
ChemistrySelect; 2/24/2021, Vol. 6 Issue 8, p1795-1803, 9p |
| Abstrakt: |
Palladium nitrsosyl carboxylates Pd3(NO)2(CX3CO2)4(ArH)2 (I: X=Cl, Ar=Ph; II: X=F, Ar=Tol) are found to be effective catalysts for C−H/C−H oxidative homocoupling of arenes bearing electron‐donor as well as electron‐withdrawing groups (EWG). Trifluoroacetate complex II is found to be more promising due to higher stability under the reaction conditions. Complex II also shows high performance in intramolecular coupling in diarylsulfides, diarylethers and diarylamines giving corresponding dibenzothiophenes, dibenzofurans and carbazoles with yields ranged from moderate to high. The plausible mechanism is studied by DFT computational analysis basing on Pd3 linear complexes as major active species. It was found that two deprotonation steps proceed in two different ways: for the first deprotonation SEAr is most probable pathway while for the second one concerted metalation‐deprotonation (CMD) is preferable. That can explain high tolerance of the system to different substrates: SEAr is favorable in the presence of electron donor group and EWG facilitate CMD. NO group was found to be involved into the CMD pathway and that is the rate‐determining step with the highest activation barrier. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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