3243-81-0Relevant articles and documents
α-Alkylation of arylacetonitriles with primary alcohols catalyzed by backbone modified N-heterocyclic carbene iridium(i) complexes
Arslan, Burcu,Gülcemal, Süleyman
, p. 1788 - 1796 (2021)
A series of backbone-modified N-heterocyclic carbene (NHC) complexes of iridium(i) (1d-f) have been synthesized and characterized. The electronic properties of the NHC ligands have been assessed by comparison of the IR carbonyl stretching frequencies of thein situprepared [IrCl(CO)2(NHC)] complexes in CH2Cl2. These new complexes (1d-f), together with previously prepared1a-c, were applied as catalysts for the α-alkylation of arylacetonitriles with an equimolar amount of primary alcohols or 2-aminobenzyl alcohol. The catalytic activities of these complexes could be controlled by modifying the N-substituents and backbone of the NHC ligands. The NHC-IrIcomplex1fbearing 4-methoxybenzyl substituents on the N-atoms and 4-methoxyphenyl groups at the 4,5-positions of imidazole exhibited the highest catalytic activity in the α-alkylation of arylacetonitriles with primary alcohols. Various α-alkylated nitriles and aminoquinolines were obtained in high yields through a borrowing hydrogen pathway by using 0.1 mol%1fand a catalytic amount of KOH (5 mol%) under an air atmosphere within significantly short reaction times.
Base-controlled chemoselectivity: direct coupling of alcohols and acetonitriles to synthesise α-alkylated arylacetonitriles or acetamides
Bai, Liang,Ge, Min-Tong,Li, Chen,Qiu, Yuan-Rui,Wang, Ying,Xia, Ai-Bao,Xu, Dan-Qian
supporting information, p. 15200 - 15204 (2021/09/06)
We achieved chemoselective synthesis of α-alkylated arylacetonitriles and acetamides by combining Ir complex-catalysed direct coupling of alcohols and nitriles by a simple adjustment of the base. Methanol and ethanol performed well as the alkylating reagents. This method of acetonitrile alkylation provided a novel approach for carbon chain extension.
Nickel-catalyzed hydrogen-borrowing strategy: Chemo-selective alkylation of nitriles with alcohols
Banerjee, Debasis,Bera, Atanu,Bera, Sourajit
supporting information, p. 6850 - 6853 (2020/07/04)
The first nickel-catalyzed hydrogen-borrowing alkylation of a series of aryl acetonitriles with a variety of aryl, heteroaryl, allylic and alkyl alcohols releasing water as the by-product (>33 examples, up to 90% yield) is reported.
Sustainable Alkylation of Nitriles with Alcohols by Manganese Catalysis
Borghs, Jannik C.,Tran, Mai Anh,Sklyaruk, Jan,Rueping, Magnus,El-Sepelgy, Osama
, p. 7927 - 7935 (2019/06/24)
A general and chemoselective catalytic alkylation of nitriles using a homogeneous nonprecious manganese catalyst is presented. This alkylation reaction uses naturally abundant alcohols and readily available nitriles as coupling partners. The reaction tolerates a wide range of functional groups and heterocyclic moieties, efficiently providing useful cyanoalkylated products with water as the only side product. Importantly, methanol can be used as a C1 source and the chemoselective C-methylation of nitriles is achieved. The mechanistic investigations support the multiple role of the metal-ligand manganese catalyst, the dehydrogenative activation of the alcohol, α-C-H activation of the nitrile, and hydrogenation of the in-situ-formed unsaturated intermediate.
Facile Ruthenium(II)-Catalyzed α-Alkylation of Arylmethyl Nitriles Using Alcohols Enabled by Metal-Ligand Cooperation
Thiyagarajan, Subramanian,Gunanathan, Chidambaram
, p. 5483 - 5490 (2017/08/17)
A facile ruthenium(II)-catalyzed α-alkylation of arylmethyl nitriles using alcohols is reported. The ruthenium pincer catalyst serves as an efficient catalyst for this atom-economical transformation that undergoes alkylation via borrowing hydrogen pathways, producing water as the only byproduct. Arylmethyl nitriles containing different substituents can be effectively alkylated using diverse primary alcohols. Notably, using ethanol and methanol as alkylating reagents, challenging ethylation and methylation of arylmethyl nitriles were performed. Secondary alcohols do not undergo alkylation reactions. Thus, phenylacetonitrile was chemoselectively alkylated using primary alcohols in the presence of secondary alcohols. Diols provided a mixture of products. When deuterium-labeled alcohol was used, the expected deuterium transposition occurred, providing both α-alkylation and α-deuteration of arylmethyl nitriles. Consumption of nitrile was monitored by GC, which indicated the involvement of first-order kinetics. Plausible mechanistic pathways are suggested on the basis of experimental evidence. The ruthenium catalyst reacts with base and generates an unsaturated intermediate, which further reacts with both nitriles and alcohols. While nitrile is transformed to enamine via [2 + 2] cycloaddition, alcohol is oxidized to aldehyde. The metal bound enamine adduct reacts with aldehyde via Michael addition, resulting in an ene-imine adduct, which perhaps undergoes direct hydrogenation by a Ru dihydride intermediate, produced from alcohol oxidation. However, in situ monitoring of the reaction mixture confirmed the presence of unsaturated vinyl nitrile in the reaction mixture in minor amounts (10%), indicating the possible dissociation of ene-imine adduct during the catalysis, which may further be hydrogenated to provide the α-alkylated nitriles. Overall, the efficient α-alkylation of nitriles using alcohols can be attributed to the amine-amide metal-ligand cooperation that is operative in the ruthenium pincer catalyst, which enables all of the catalytic intermediates to remain in the +2 oxidation state throughout the catalytic cycle.
