نتایج جستجو برای: carbene reaction
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Benzyl bromides and related molecules are among the most common substrates in organic synthesis. They are typically used as electrophiles in nucleophilic substitution reactions. These molecules can also be activated via single-electron-transfer (SET) process for radical reactions. Representative recent progress includes α-carbon benzylation of ketones and aldehydes via photoredox catalysis. Her...
Theoretical calculations on the gas-phase thermal decomposition of dimethyldiazirine, diethyldiazirine and difluorodiazirine have been carried out using ab initio composite methods CBS-QB3 and G3, and DFT CAM-B3LYP, MPW1PW91, PBE1PBE and M062X. Reasonable agreement has been found with the experimental values by the G3 method. Two possible mechanisms were studied: Mechanism A consists the openin...
The metalloradical activation of ortho-benzallylaryl N-tosyl hydrazones with [Co(TPP)] (TPP=tetraphenylporphyrin) as the catalyst enabled the controlled exploitation of the single-electron reactivity of the redox non-innocent carbene intermediate. This method offers a novel route to prepare eight-membered rings, using base metal catalysis to construct a series of unique dibenzocyclooctenes thro...
Effective methods of ligand design have been highly sought due to the significant roles of ligands in controlling metal catalyses. In particular, easy-to-handle ligands to realize high reaction efficacy, substrate tolerance, and environmental friendliness are desirable. Novel bidentate ligands containing N-heterocyclic carbene and thioether moieties were developed based on findings of hemilabil...
The coordination versatility of a 1,3,5-triphenylbenzene-tris-mesoionic carbene ligand is illustrated by the preparation of complexes with three different metals: rhodium, iridium and nickel. The rhodium and iridium complexes contained the [MCl(COD)] fragments, while the nickel compound contained [NiCpCl]. The preparation of the tris-MIC (MIC = mesoionic carbene) complex with three [IrCl(CO)2] ...
The first example of the use of an N-heterocyclic carbene (NHC) as an organocatalyst for the activation of isocyanides was demonstrated. On the basis of previous reports on the interaction between NHCs and isocyanides, we developed a catalytic cycle involving transient imidoyl intermediate. The reaction of ketones with isocyanides produced the corresponding enaminones with high efficiency. Cont...
Predictive catalysis was applied to the reaction of pyridinium 1,4-zwitterionic thiolates with a copper carbene. Theoretical calculations were first performed determine suitability their annulation and make predictions about performance different salts, diazo species, derivatives. With in hand, experimental conditions optimized, scope assessed, precision evaluated. Yields up 90% obtained for sy...
The first example of the use of an N-heterocyclic carbene (NHC) as an organocatalyst for the activation of isocyanides was demonstrated. On the basis of previous reports on the interaction between NHCs and isocyanides, we developed a catalytic cycle involving transient imidoyl intermediate. The reaction of ketones with isocyanides produced the corresponding enaminones with high efficiency. Cont...
Silicondiselenide is a semiconductor and exists as an insoluble polymer (SiSe2) n which is prepared by reacting elemental silicon with selenium powder in the temperature range of 400-850 °C. Herein, we report on the synthesis, isolation, and characterization of carbene stabilized molecular silicondiselenide in the form of (cAAC)2Si2Se4 (3) [cAAC = cyclic alkyl(amino)carbene]. 3 is synthesized v...
The title complex, [Re(2)(C(27)H(25)N(2)O(2))H(CO)(8)]·0.67C(4)H(8)O, was formed as a product in the reaction of a rhenium(I)-Fischer carbene complex with a free NHC carbene. The coordination environment about the two Re atoms is slightly distorted octahedral, including a bridging H atom. The imidazolium and furan groups are almost coplanar, whereas the mesityl substituents show an almost perpe...
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