346-06-5Relevant articles and documents
Structural Elucidation of Silver(I) Amides and Their Application as Catalysts in the Hydrosilylation and Hydroboration of Carbonyls
Blair, Victoria L.,Boutland, Aaron J.,Kelly, John A.,Orr, Samantha A.
supporting information, p. 4947 - 4951 (2020/04/22)
This study details the isolation and characterisation of three novel silver(I) amides in solution and solid-state, [Ag(Cy3P)(HMDS)] 2, [Ag(Cy3P){N(TMS)(Dipp)}] 3 and [Ag(Cy3P)2(NPh2)] 4. Their catalytic abilities have proved successful in hydroboration and hydrosilylation reactions with a full investigation performed with complex 2. Both protocols proceed under mild conditions, displaying exceptional functional-group tolerance and chemoselectivity, in excellent conversions at competitive reaction times. This work reveals the first catalytic hydroboration of aldehydes and ketones performed by a silver(I) catalyst.
Polypyridyl iridium(III) based catalysts for highly chemoselective hydrogenation of aldehydes
Pandrala, Mallesh,Resendez, Angel,Malhotra, Sanjay V.
, p. 283 - 288 (2019/09/30)
Iridium-catalyzed transfer hydrogenation (TH) of carbonyl compounds using HCOOR (R = H, Na, NH4) as a hydrogen source is a pivotal process as it provides the clean process and is easy to execute. However, the existing highly efficient iridium catalysts work at a narrow pH; thus, does not apply to a wide variety of substrates. Therefore, the development of a new catalyst which works at a broad pH range is essential as it can gain a broader scope of utilization. Here we report highly efficient polypyridyl iridium(III) catalysts, [Ir(tpy)(L)Cl](PF6)2 {where tpy = 2,2′:6′,2′'-Terpyridine, L = phen (1,10-Phenanthroline), Me2phen (4,7-Dimethyl-1,10-phenanthroline), Me4phen (3,4,7,8-Tetramethyl-1,10-phenanthroline), Me2bpy (4,4′-Dimethyl-2–2′-dipyridyl)} for the chemoselective reduction of aldehydes to alcohols in aqueous ethanol and sodium formate as the hydride source. The reaction can be carried out efficiently in broad pH ranges, from pH 6 to 11. These catalysts are air stable, easy to prepare using commercially available starting materials, and are highly applicable for a wide range of substrates, such as electron-rich or deficient (hetero)arenes, halogens, phenols, alkoxy, ketones, esters, carboxylic acids, cyano, and nitro groups. Particularly, acid and hydroxy groups containing aldehydes were reduced successfully in basic and acidic reaction conditions, demonstrating the efficiency of the catalyst in a broad pH range with high conversion rates under microwave irradiation.
Cooperative interplay between a flexible PNN-Ru(II) complex and a NaBH4 additive in the efficient catalytic hydrogenation of esters
Wang, Zheng,Chen, Xiangyang,Liu, Bo,Liu, Qing-Bin,Solan, Gregory A.,Yang, Xinzheng,Sun, Wen-Hua
, p. 1297 - 1304 (2017/05/05)
A catalyst loading of between 0.001-0.05 mol% of the PNN-bearing ruthenium(II) complex [fac-PNN]RuH(PPh3)(CO) (PNN = 8-(2-diphenylphosphinoethyl)amidotrihydroquinoline), in combination with 5 mol% NaBH4, efficiently catalyzes the hydrogenation of esters to their corresponding alcohols under mild pressures of hydrogen. Both aromatic and aliphatic esters can be converted with high values of TON or TOF achievable. Mechanistic investigations using both DFT calculations and labeling experiments highlight the cooperative role of NaBH4 in the catalysis while the catalytically active species has been established as trans-dihydride [mer-PNHN]RuH2(CO) (PNHN = 8-(2-diphenylphosphinoethyl)aminotrihydroquinoline). The stereo-structure of the PNHN-ruthenium species greatly affects the activity of the catalyst, and indeed the cis-dihydride isomer [fac-PNHN]RuH2(CO) is unable to catalyze the hydrogenation of esters until ligand reorganization occurs to give the trans isomer.
