scholarly journals Palladium-heterogenized porous polyimide materials as effective and recyclable catalysts for reactions in water

2015 ◽  
Vol 17 (1) ◽  
pp. 466-473 ◽  
Author(s):  
E. Rangel Rangel ◽  
E. M. Maya ◽  
F. Sánchez ◽  
J. G. de la Campa ◽  
M. Iglesias

Functionalized porous polyimides were used as supports for palladium complexes leading to efficient catalysts for the Suzuki cross-coupling of water.

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Radomir Jasiński ◽  
Oleg M. Demchuk ◽  
Dmytro Babyuk

The DFT calculations of the simplified model of the asymmetric Suzuki–Miyaura coupling reaction were performed at the M062x/LANL2DZ theory level at first. It was found that enantioselective reactions mediated by the palladium complexes of chiral C,P-ligands follow a four-stage mechanism similar to that proposed previously as one of the most credible mechanisms. It should be underlined that the presence of substituents in the substrates and the chiral ligand at ortho positions determines the energies of possible diastereoisomeric transition states and intermediates in initial reaction steps. This suggests that, in practice, a sharp selection of theoretically possible paths of chirality transfer from the catalyst to the product should have a place and, therefore, the absolute configuration of the formed atropisomeric product is defined and can be predicted.


2021 ◽  
Author(s):  
Mickaël Avanthay ◽  
Robin Bedford ◽  
Callum Begg ◽  
Dietrich Böse ◽  
Jonathan Clayden ◽  
...  

A recent report in Nature Catalysis detailed the potentially paradigm-shifting organocatalysis of Suzuki cross-coupling of aryl halides with aryl boronic acids, catalysed by simple amine species. We have conducted a reinvestigation of key claims in this paper across multiple academic and industrial laboratories that shows that the observed catalytic activity cannot be due to the amine, but rather is due to tricyclohexylphosphine palladium complexes that are readily entrained during the purification of the amine<b>.</b>


Catalysts ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 141 ◽  
Author(s):  
Vladimir Mikhaylov ◽  
Viktor Sorokoumov ◽  
Denis Liakhov ◽  
Alexander Tskhovrebov ◽  
Irina Balova

Two types of immobilized on the amino-functionalized polystyrene-supported acyclic diaminocarbene palladium complexes (ADC-PdII) are investigated under Sonogashira cross-coupling conditions. Depending on substituents in the diaminocarbene fragment immobilized ADC-PdII, systems are found to have different catalytic activity and stability regarding Pd-leaching. PdII-diaminocarbenes possessing protons at both nitrogen atoms smoothly decompose into Pd0-containing species providing a catalytic “cocktail system” with high activity and ability to reuse within nine runs. Polymer-supported palladium (II) complex bearing NBn–Ccarbene–NH-moiety exhibits greater stability while noticeably lower activity under Sonogashira cross-coupling. Four molecular ADC-PdII complexes are also synthesized and investigated with the aim of confirming proposed base-promoted pathway of ADC-PdII conversion through carbodiimide into an active Pd0 forms.


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