scholarly journals Si–C(sp3) bond activation through oxidative addition at a Rh(i) centre

2020 ◽  
Vol 49 (17) ◽  
pp. 5416-5419
Author(s):  
S. Azpeitia ◽  
A. J. Martínez-Martínez ◽  
M. A. Garralda ◽  
A. S. Weller ◽  
M. A. Huertos

Rhodium promoted a fast, quantitative and room temperature Si–CH3 bond activation.

2011 ◽  
Vol 30 (14) ◽  
pp. 3691-3693 ◽  
Author(s):  
Siu Yin Lee ◽  
Tsz Ho Lai ◽  
Kwong Shing Choi ◽  
Kin Shing Chan

2020 ◽  
Author(s):  
Feriel Rekhroukh ◽  
Wenyi Chen ◽  
Ryan Brown ◽  
Andrew J. P. White ◽  
Mark Crimmin

A palladium pre-catalyst, [Pd(PCy<sub>3</sub>)<sub>2</sub>] is reported for the efficient and selective C–F alumination of fluorobenzenes with the aluminium(I) reagent [{(ArNCMe)<sub>2</sub>CH}Al] (<b>1</b>, Ar = 2,6-di-iso-propylphenyl). The catalytic protocol results in the transformation of sp<sup>2</sup> C–F bonds to sp<sup>2</sup> C–Al bonds and provides a route into reactive organoaluminium complexes (<b>2a-h</b>) from fluorocarbons. The catalyst is highly active. Reactions proceed within 5 minutes at 25 ºC (and at appreciable rates at even –50 ºC) and the scope includes low-fluorine-content substrates such as fluorobenzene, difluorobenzenes and trifluorobenzenes. The reaction proceeds with complete chemoselectivity (C–F vs C–H) and high regioselectivities ( >90% for C–F bonds adjacent to the most acidic C–H sites). The heterometallic complex [Pd(PCy<sub>3</sub>)(<b>1</b>)<sub>2</sub>] was shown to be catalytically competent. Catalytic C–F alumination proceeds with a KIE of 1.1–1.3. DFT calculations have been used to model potential mechanisms for C–F bond activation. These calculations suggest that two competing mechanisms may be in operation. Pathway 1 involves a ligand-assisted oxidative addition to [Pd(<b>1</b>)<sub>2</sub>] and leads directly to the product. Pathway 2 involves a stepwise C–H to C–F functionalisation mechanism in which the C–H bond is broken and reformed along the reaction coordinate, allowing it to act as a directing group for the adjacent C–F site. This second mechanism explains the experimentally observed regioselectivity. Experimental support for this C–H activation playing a key role in C–F alumination was obtained by employing [{(MesNCMe)<sub>2</sub>CH}AlH<sub>2</sub>] (<b>3</b>, Mes = 2,4,6-trimethylphenyl) as a reagent in place of 1. In this instance, the kinetic C–H alumination intermediate could be isolated. Under catalytic conditions this intermediate converts to the thermodynamic C–F alumination product.


2019 ◽  
Vol 43 (21) ◽  
pp. 8005-8014 ◽  
Author(s):  
Asma Nahaei ◽  
S. Masoud Nabavizadeh ◽  
Fatemeh Niroomand Hosseini ◽  
S. Jafar Hoseini ◽  
Mahdi M. Abu-Omar

A combined experimental/computational investigation reveals that the cyclometalation of [PtMe2(DMSO)2], 1, by HC^N ligands proceeds via HC^N coordination through the N donor atom, oxidative addition of the arene C–H bond, and final dissociation of methane from a platinum hydride complex.


2016 ◽  
Vol 52 (88) ◽  
pp. 12960-12963 ◽  
Author(s):  
Andrea Monas ◽  
Krunoslav Užarević ◽  
Ivan Halasz ◽  
Marina Juribašić Kulcsár ◽  
Manda Ćurić

Room-temperature accelerated aging in the solid state has been applied for quantitative azobenzene C–H bond activation by Pd(OAc)2. Water-soluble dicyclopalladated methyl orange is a selective chromogenic biothiol sensor at physiologically-relevant micromolar concentrations in aqueous media.


2008 ◽  
Vol 47 (11) ◽  
pp. 2074-2078 ◽  
Author(s):  
Jordi García-Antón ◽  
M. Rosa Axet ◽  
Susanna Jansat ◽  
Karine Philippot ◽  
Bruno Chaudret ◽  
...  

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