The reaction of 2-substituted imidazolinium salt with bis-Grignard reagents is reported and a new method for the synthesis of symmetric diketones from carboxylic acids and bis-Grignard reagents is provided.
As models of 5, 10-methenyl-tetrahydrofolate coenaymes imidazolinium salts 6a. b were synthesized and their carbon transfer reactions with several types of nucleophiles were studied.
Tetrahydrofolate (THF) coenzymes are involved in biochemical transfer of aone-carbon fragment at different oxidation levels. The study of THF models may providea valuable class of reagents for group transfer reactions...Tetrahydrofolate (THF) coenzymes are involved in biochemical transfer of aone-carbon fragment at different oxidation levels. The study of THF models may providea valuable class of reagents for group transfer reactions with practical significance. Onlya few researches about 5, 10-methenyl-THF models have been reported in literature.展开更多
One-carbon unit transfer reaction of folate cofactor model compound, 1-acetyl-2-methyl-imidazolinium, with 1,2-diaminobenzene has been studied theoretically with ONIOM method. The result shows that there are two pathw...One-carbon unit transfer reaction of folate cofactor model compound, 1-acetyl-2-methyl-imidazolinium, with 1,2-diaminobenzene has been studied theoretically with ONIOM method. The result shows that there are two pathways to complete this reaction because the imidazolinium ring has two breaking patterns. Both the two pathways have six steps. They are combination of two reactants, proton migration, break of five-membered ring, formation of benzimidazole derivate, another proton migration, and formation of final products. In each of the above pathways, the two proton migration steps have higher energy, which illuminate that the reaction is catalyzed by general acid-base. This fact agrees with the experimental results of enzymatic one-carbon unit transfer at oxidation level of formate.展开更多
Two new bis-imidazolinium salts (4a, 4b) have been synthesized as precursors of N-heterocyclic carbenes (NHCs) from the commercially available (R)-2,2′-dihydroxy-1,1′-binaphthalene. The two bis-imidazolinium salts w...Two new bis-imidazolinium salts (4a, 4b) have been synthesized as precursors of N-heterocyclic carbenes (NHCs) from the commercially available (R)-2,2′-dihydroxy-1,1′-binaphthalene. The two bis-imidazolinium salts were used as efficient precursor of NHC ancillary ligands in the palladium-catalyzed Heck reaction. Good to excellent yields and high stereoselectivities were obtained with ethyl acrylate, acrylonitrile, and acrylamide as starting materials. The structure of bis-imidazolinium salt 4b was further characterized by single crystal X-ray diffraction analysis.展开更多
One-carbon unit transfer reaction of imidazolinium with 1,2-diaminobenzene has been studied with semi-empirical molecular orbital calculations, PM3. The result shows that there are two ways to complete this reaction b...One-carbon unit transfer reaction of imidazolinium with 1,2-diaminobenzene has been studied with semi-empirical molecular orbital calculations, PM3. The result shows that there are two ways to complete this reaction because the imidazolinium ring has two different breaking patterns. These two ways both have seven steps, including two proton-migrating steps that limit the rate of the reaction. The structures and energies of the intermediates and transition states have been calculated.展开更多
基金This work was supported by the National NatUral Science Foundation of China the Provincial Natural Science Foundation of Sha
文摘The reaction of 2-substituted imidazolinium salt with bis-Grignard reagents is reported and a new method for the synthesis of symmetric diketones from carboxylic acids and bis-Grignard reagents is provided.
基金This work was supported by the National Natural Science Foundation of China and Shanxi Natural Science Foundation
文摘As models of 5, 10-methenyl-tetrahydrofolate coenaymes imidazolinium salts 6a. b were synthesized and their carbon transfer reactions with several types of nucleophiles were studied.
基金Project supported by the Chinese Science Foundation and Shanxi Provincial Science Foundation.
文摘Tetrahydrofolate (THF) coenzymes are involved in biochemical transfer of aone-carbon fragment at different oxidation levels. The study of THF models may providea valuable class of reagents for group transfer reactions with practical significance. Onlya few researches about 5, 10-methenyl-THF models have been reported in literature.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29973021).
文摘One-carbon unit transfer reaction of folate cofactor model compound, 1-acetyl-2-methyl-imidazolinium, with 1,2-diaminobenzene has been studied theoretically with ONIOM method. The result shows that there are two pathways to complete this reaction because the imidazolinium ring has two breaking patterns. Both the two pathways have six steps. They are combination of two reactants, proton migration, break of five-membered ring, formation of benzimidazole derivate, another proton migration, and formation of final products. In each of the above pathways, the two proton migration steps have higher energy, which illuminate that the reaction is catalyzed by general acid-base. This fact agrees with the experimental results of enzymatic one-carbon unit transfer at oxidation level of formate.
基金support from the National Natural Science Foundation of China (20932004, 21072093)the National Basic Research Program of China (2011CB808600)+1 种基金the Program for New Century Excellent Talents in University (NCET-07-0425)the Doctoral Fund of Ministry of Education of China (20090091110017)
文摘Two new bis-imidazolinium salts (4a, 4b) have been synthesized as precursors of N-heterocyclic carbenes (NHCs) from the commercially available (R)-2,2′-dihydroxy-1,1′-binaphthalene. The two bis-imidazolinium salts were used as efficient precursor of NHC ancillary ligands in the palladium-catalyzed Heck reaction. Good to excellent yields and high stereoselectivities were obtained with ethyl acrylate, acrylonitrile, and acrylamide as starting materials. The structure of bis-imidazolinium salt 4b was further characterized by single crystal X-ray diffraction analysis.
文摘One-carbon unit transfer reaction of imidazolinium with 1,2-diaminobenzene has been studied with semi-empirical molecular orbital calculations, PM3. The result shows that there are two ways to complete this reaction because the imidazolinium ring has two different breaking patterns. These two ways both have seven steps, including two proton-migrating steps that limit the rate of the reaction. The structures and energies of the intermediates and transition states have been calculated.
