- STRONGLY LEWIS ACIDIC METAL-ORGANIC FRAMEWORKS FOR CONTINUOUS FLOW CATALYSIS
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Lewis acidic metal-organic framework (MOF) materials comprising triflate-coordinated metal nodes are described. The materials can be used as heterogenous catalysts in a wide range of organic group transformations, including Diels-Alder reactions, epoxide-ring opening reactions, Friedel-Crafts acylation reactions and alkene hydroalkoxylation reactions. The MOFs can also be prepared with metallated organic bridging ligands to provide heterogenous catalysts for tandem reactions and/or prepared as composites with support particles for use in columns of continuous flow reactor systems. Methods of preparing and using the MOF materials and their composites are also described.
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Paragraph 0216-0219; 0222; 0239; 0255
(2021/02/26)
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- An efficient and green method for regio- and chemo-selective Friedel-Crafts acylations using a deep eutectic solvent ([CholineCl][ZnCl2]3)
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[CholineCl][ZnCl2]3, a deep eutectic solvent between choline chloride and ZnCl2, has been used as a dual function catalyst and green solvent for the Friedel-Crafts acylation of aromatic compounds instead of using the moisture-sensitive Lewis acids and volatile organic solvents. The reactions are performed with high yields under microwave irradiation with short reaction times for the synthesis of ketones. Interestingly, indole derivatives are regioselectively acylated in the 3-position under mild conditions with high yields without NH protection. Three new ketone products are synthesized. [CholineCl][ZnCl2]3 is easily synthesized from choline chloride and zinc chloride at a low cost, with easy purification and environmentally benign compounds. [CholineCl][ZnCl2]3 can be reused up to five times without loss of catalytic activity, making it ideal in industrial processes.
- Tran, Phuong Hoang,Nguyen, Hai Truong,Hansen, Poul Erik,Le, Thach Ngoc
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p. 37031 - 37038
(2016/05/24)
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- DMF as carbon source: Rh-catalyzed α-methylation of ketones
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An unprecedented Rh-catalyzed direct methylation of ketones with N,N-dimethylformamide (DMF) is disclosed. The reaction shows a broad substrate scope, tolerating both aryl and alkyl ketones with various substituents. Mechanistic studies suggest that DMF delivers a methylene fragment followed by a hydride in the methylation process.
- Li, Yang,Xue, Dong,Lu, Wei,Wang, Chao,Liu, Zhao-Tie,Xiao, Jianliang
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supporting information
p. 66 - 69
(2014/01/23)
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- Hafnium(IV)Trifluoromethanesulfonate, An Efficient Catalyst for the Friedel-Crafts Acylation and Alkylation Reactions
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Hafnium(IV) trifluoromethanesulfonate (hafnium(IV) triflate, Hf(OTf)4) was synthesized from hafnium tetrachloride and trifluoromethanesulfonic acid.The triflate thus prepared was found to be effective in the catalytic Friedel-Crafts acylation reactions of various substituted benzenes with acid anhydrides in lithium perchlorate-nitromethane (LiClO4-MeNO2).Lithium perchlorate-nitromethane is an excellent solvent system, and the catalytic activity of the Lewis acid was much improved in this medium.The product was obtained in up to 250000percent molar amounts baaed on the catalyst.Hafnium(IV) triflate was also found to be quite effective in the catalytic Friedel-Crafts alkylation reactions of aromatic compounds with alkyl chlorides.The reactions proceeded smoothly in the presence of 5percent molar amount of Hf(OTf)4 and 50percent molar amount of LiClO4 by using a slow addition procedure.
- Hachiya, Iwao,Moriwaki, Mitsuhiro,Kobayashi, Shu
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p. 2053 - 2060
(2007/10/02)
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