4626-58-8Relevant articles and documents
Dinuclear gold(i) complexes bearing alkyl-bridged bis(n-heterocyclic carbene) ligands as catalysts for carboxylative cyclization of propargylamine: Synthesis, structure, and kinetic and mechanistic comparison to the mononuclear complex [Au(IPr)Cl]
Bayrakdar, Tahani A.C.A.,Nahra, Fady,Davis, Jack V.,Gamage, Mohan M.,Captain, Burjor,Temprado, Manuel,Marazzi, Marco,Saab, Marina,van Hecke, Kristof,Ormerod, Dominic,Hoff, Carl D.,Nolan, Steven P.
, p. 2907 - 2916 (2020)
Eight new dinuclear gold(I) complexes, [Au2(L)X2] (1?8), were synthesized using a straightforward synthetic procedure under very mild conditions. The complexes have been characterized by NMR spectroscopy, elemental analysis, and single-crystal X-ray structure analysis. Their catalytic activity was investigated in the carboxylative cyclization of propargylamine (PPA). A superior performance in comparison to [Au(IPr)Cl] (9) was obtained for complexes 1 and 2 having an eight-methylene bridge connecting two NHCs with an arene bearing an isopropyl substituent for X = Cl, Br. This prompted more detailed kinetic and mechanistic studies by FTIR comparing dinuclear complex 2 of X = Cl to complex 9. Fortuitously the FTIR studies allowed monitoring of the formation of the products carbamic acid (CA) and carbamate salt (CS), as well as a key cyclized intermediate first discovered by Ikariya. These data allow additional insight into the mechanism as well as the central role which may be played by Au(I) carbamate formation as a higher energy resting state present in the catalytic cycle. The crystal structures of four of the new complexes and a detailed computational study relevant to the role of carbamic acid (CA) and carbamates in the catalytic cycle are also reported.
Non-Noble-Metal Metal-Organic-Framework-Catalyzed Carboxylative Cyclization of Propargylic Amines with Atmospheric Carbon Dioxide under Ambient Conditions
Gu, Ai-Ling,Wang, Wan-Ting,Cheng, Xin-Yu,Hu, Tian-Ding,Wu, Zhi-Lei
supporting information, p. 13425 - 13433 (2021/08/30)
The coupling reaction of propargylic amines and carbon dioxide (CO2) to synthesize 2-oxazolidinones is an important reaction in industrial production, and yet harsh reaction conditions and noble-metal catalysts are often required to achieve high product yields. Herein, one novel noble-metal-free three-dimensional framework, [Mg3Cu2I2(IN)4(HCOO)2(DEF)4]n (1), assembled by magnesium and copper clusters was synthesized and applied to this reaction. Compound 1 displays excellent solvent stability. Importantly, 1, acting as heterogeneous catalyst, can highly catalyze the cyclization of propargylic amines with CO2 under atmospheric pressure at room temperature, which can be recycled at least five times without an obvious decrease of the catalytic activity. NMR spectroscopy, coupled with 13C-isotope- and deuterium-labeling experiments, clearly clarifies the mechanism of this catalytic system: CO2 was successfully captured and converted to the product of 2-oxazolidinones, the CC bond of propargylic amines can be effectively activated by 1, and proton transfer was involved in the reaction process. Density functional theory calculations are further conducted to uncover the reaction path and the crucial role of compound 1 during the reaction.
Palladium-Catalyzed Carbo-Oxygenation of Propargylic Amines using in Situ Tether Formation
Greenwood, Phillip D. G.,Grenet, Erwann,Waser, Jerome
supporting information, p. 3010 - 3013 (2019/02/07)
1,2-Amino alcohols and α-aminocarbonyls are frequently found in natural products, drugs, chiral auxiliaries, and catalysts. This work reports a new method for the palladium-catalyzed oxyalkynylation and oxyarylation of propargylic amines. The reaction is perfectly regioselective based on the in situ introduction of a hemiacetal tether derived from trifluoroacetaldehyde. cis-Selective carbo-oxygenation was achieved for terminal alkynes, whereas internal alkynes gave trans-carbo-oxygenation products. The obtained enol ethers could be easily transformed into 1,2-amino alcohols or α-amino ketones using hydrogenation or hydrolysis, respectively.
