The ab initio method has been used to study the 1-3 H transfer reaction on formamidine substituted by halogen. The calculation results show that the substituted halogen has two effects on the 1-3 H transfer reaction...The ab initio method has been used to study the 1-3 H transfer reaction on formamidine substituted by halogen. The calculation results show that the substituted halogen has two effects on the 1-3 H transfer reaction: decreasing the activation energy and stabilizing the C=N double bond owing to the conjugative effect of p-π-p of products and transition states.展开更多
For the isomerization reaction of monofluoro-disilene,the geometrical structures of reac- tant,product and transition state have been optimized and energy constant,vibrational frequency calculated.By means of the stat...For the isomerization reaction of monofluoro-disilene,the geometrical structures of reac- tant,product and transition state have been optimized and energy constant,vibrational frequency calculated.By means of the statistical thermodynamics and Eyring's transition state theory,the equilibrium constant,rate constant and heat of isomerization have also been computed.Hence, this reaction has been analysed completely.展开更多
Organosilicon compounds are widely valuable,making the efficient synthesis of alkenyl silanes an important research goal.A novel catalytic system based on a tridentate anionic ligand and cobalt has been developed for ...Organosilicon compounds are widely valuable,making the efficient synthesis of alkenyl silanes an important research goal.A novel catalytic system based on a tridentate anionic ligand and cobalt has been developed for the Markovnikov-selective hydrosilylation of terminal aliphatic alkynes,followed by isomerization of the disubstituted alkenyl silane intermediate,providing efficient access to trisubstituted alkenyl silanes.This system is also highly effective for the Markovnikov hydrosilylation of aryl alkynes.The protocol demonstrates broad functional group tolerance and can be performed on a gram scale.The catalyst achieves a turnover number(TON)of up to 1760 in hydrosilylation reaction.Mechanistic studies suggest that the anionic ligand,upon coordination,forms a dual functional catalyst with cobalt,which is key to enabling this transformation.It is proposed that a cobalt-hydride species selectively catalyzes both the hydrosilylation of terminal alkynes and the subsequent isomerization of the disubstituted alkenyl silane.This work provides an efficient and selective synthetic method using an earth-abundant metal catalyst for alkene synthesis via hydrosilylation and isomerization.展开更多
An efficient method for the synthesis of benzo[b]benzofurano[2,3-e][1,6]naphthyridine-8-one derivatives has been developed via Pictet-Spengler reaction of 4-（3-aminobenzofuran-2-yl）quinoline-2-ones,which could be ob...An efficient method for the synthesis of benzo[b]benzofurano[2,3-e][1,6]naphthyridine-8-one derivatives has been developed via Pictet-Spengler reaction of 4-（3-aminobenzofuran-2-yl）quinoline-2-ones,which could be obtained from alkylation of 4-bromomethylquinoline-2-ones with salicylonitrile and subsequent Thorpe-Ziegier isomerization,with aromatic aldehydes under p-TsOH as catalyst in good yields.展开更多
An efficient method for the preparation of thieno[3＇,2＇：2,3]pyrido[4,5-d]thiazolo[3,2-a] pyrimidin-5-ones 5 is described. The key intermediate, 7-（3-amino-4-cyano-5-phenyl aminothieno-2-yl）-5H-thiazolo-[80_TD$IF]...An efficient method for the preparation of thieno[3＇,2＇：2,3]pyrido[4,5-d]thiazolo[3,2-a] pyrimidin-5-ones 5 is described. The key intermediate, 7-（3-amino-4-cyano-5-phenyl aminothieno-2-yl）-5H-thiazolo-[80_TD$IF]3,2-a]pyrimidin-5-one（3）, was synthesized from 7-chloromethyl-5H-thiazolo[3,2-a]pyrimidin-5-one（1）with potassium-（2,2-dicyano-1-phenylaminoethen-1-yl）thiolate（2） by Thorpe–Ziegler isomerization.Subsequent reaction of the intermediate amine with aromatic aldehydes via Pictet–Spengler reaction provided thieno-pyridine fused thiazolo[3,2-a]pyrimidines under p-Ts OH as catalyst in good yields.展开更多
The structures of singlet stannylenoid H2SnLiF have been examined by ab initio MO theory. Four equilibrium states and three transition states of isomerization reaction are located. The calculation shows that the p-com...The structures of singlet stannylenoid H2SnLiF have been examined by ab initio MO theory. Four equilibrium states and three transition states of isomerization reaction are located. The calculation shows that the p-complex 1 is the most stable and experimentally detectable. The other three species, three-membered ring 2, o-complex 3 and tetrahedron 4, are also local minima on the potential energy surface, but are higher in energy.展开更多
基金Supported by the Yunnan Provincial Science and Technology Department (2003A0003M)
文摘The ab initio method has been used to study the 1-3 H transfer reaction on formamidine substituted by halogen. The calculation results show that the substituted halogen has two effects on the 1-3 H transfer reaction: decreasing the activation energy and stabilizing the C=N double bond owing to the conjugative effect of p-π-p of products and transition states.
基金This research was supported by the National Natural Science Foundation of China.
文摘For the isomerization reaction of monofluoro-disilene,the geometrical structures of reac- tant,product and transition state have been optimized and energy constant,vibrational frequency calculated.By means of the statistical thermodynamics and Eyring's transition state theory,the equilibrium constant,rate constant and heat of isomerization have also been computed.Hence, this reaction has been analysed completely.
基金National Key Research and Development Program of China(2021YFA1500200)National Natural Science Foundation of China(NSFC)(22525109)+1 种基金Zhejiang Provincial Natural Science Foundation of China(LDQ24B020001)the Fundamental Research Funds for the Central Universities(226-2022-00224 and 226-2024-00003).
文摘Organosilicon compounds are widely valuable,making the efficient synthesis of alkenyl silanes an important research goal.A novel catalytic system based on a tridentate anionic ligand and cobalt has been developed for the Markovnikov-selective hydrosilylation of terminal aliphatic alkynes,followed by isomerization of the disubstituted alkenyl silane intermediate,providing efficient access to trisubstituted alkenyl silanes.This system is also highly effective for the Markovnikov hydrosilylation of aryl alkynes.The protocol demonstrates broad functional group tolerance and can be performed on a gram scale.The catalyst achieves a turnover number(TON)of up to 1760 in hydrosilylation reaction.Mechanistic studies suggest that the anionic ligand,upon coordination,forms a dual functional catalyst with cobalt,which is key to enabling this transformation.It is proposed that a cobalt-hydride species selectively catalyzes both the hydrosilylation of terminal alkynes and the subsequent isomerization of the disubstituted alkenyl silane.This work provides an efficient and selective synthetic method using an earth-abundant metal catalyst for alkene synthesis via hydrosilylation and isomerization.
基金financial support from the Science and Technology Department of Liaoning Province(No.2011220022)
文摘An efficient method for the synthesis of benzo[b]benzofurano[2,3-e][1,6]naphthyridine-8-one derivatives has been developed via Pictet-Spengler reaction of 4-（3-aminobenzofuran-2-yl）quinoline-2-ones,which could be obtained from alkylation of 4-bromomethylquinoline-2-ones with salicylonitrile and subsequent Thorpe-Ziegier isomerization,with aromatic aldehydes under p-TsOH as catalyst in good yields.
基金partially supported by innovation team project of Liaoning Province Education Department(No.2015001)
文摘An efficient method for the preparation of thieno[3＇,2＇：2,3]pyrido[4,5-d]thiazolo[3,2-a] pyrimidin-5-ones 5 is described. The key intermediate, 7-（3-amino-4-cyano-5-phenyl aminothieno-2-yl）-5H-thiazolo-[80_TD$IF]3,2-a]pyrimidin-5-one（3）, was synthesized from 7-chloromethyl-5H-thiazolo[3,2-a]pyrimidin-5-one（1）with potassium-（2,2-dicyano-1-phenylaminoethen-1-yl）thiolate（2） by Thorpe–Ziegler isomerization.Subsequent reaction of the intermediate amine with aromatic aldehydes via Pictet–Spengler reaction provided thieno-pyridine fused thiazolo[3,2-a]pyrimidines under p-Ts OH as catalyst in good yields.
文摘The structures of singlet stannylenoid H2SnLiF have been examined by ab initio MO theory. Four equilibrium states and three transition states of isomerization reaction are located. The calculation shows that the p-complex 1 is the most stable and experimentally detectable. The other three species, three-membered ring 2, o-complex 3 and tetrahedron 4, are also local minima on the potential energy surface, but are higher in energy.
