The carbon-carbon bond is the one of the most fundamental and abundant bonds that exist in organic molecules,and the challenge of functionalization of carbon-carbon bond has always been a critical pursuit in organic s...The carbon-carbon bond is the one of the most fundamental and abundant bonds that exist in organic molecules,and the challenge of functionalization of carbon-carbon bond has always been a critical pursuit in organic synthesis.In recent years,there have been a growing number of studies on the C-C bond activation.Nevertheless,the metal-catalyzed cleavage of the C-C(O)bond in unstrained ketones has remained relatively underexplored due to the strong affinity of carbonyl groups for metals.In this study,we report a nickel-catalyzed strategy for the reductive alkynylation of ketoimines viaβ-carbon elimination.This method involves the conversion of aryl ketones into aryl ketoimines,thus expanding the toolbox of aryl electrophiles.The use of a N-heterocyclic carbene(NHC)ligand is crucial for this catalytic transformation.This discovery leads to a cross electrophile coupling reaction characterized by its operational simplicity,unique chemo-selectivity and excellent functional group tolerance.In addition,the approach has been effectively applied to the late-stage alkynylation of diverse pharmaceuticals.Ultimately,a series of comprehensive experiments and theoretical studies were conducted to provide insights into the reaction pathway,which supports the proposedβ-carbon elimination process.展开更多
C-C bond activation has emerged as a powerful tool for the construction of complex molecules.Herein,we report a dual ligands relay-promoted transformation of unstrained aryl,alkenyl and alkynyl ketones to the correspo...C-C bond activation has emerged as a powerful tool for the construction of complex molecules.Herein,we report a dual ligands relay-promoted transformation of unstrained aryl,alkenyl and alkynyl ketones to the corresponding polyfluoroarenes and nitriles via C-C(=O)bond cleavage and subsequent decarboxylative arylation process.Various polyfluoroarene and nitrile products are obtained in one pot under cyanide-free conditions.The protocol features high atom economy,broad functional group tolerance and excellent heterocyclic compatibility.The late-stage functionalization of the drug and natural product demonstrated the synthetic utility of our protocol.Furthermore,the decisive role of the dual ligands was clarified and the mechanistic rationale including theβ-C elimination as the rate-limiting step was supported by detailed density functional theory(DFT)studies.展开更多
InAlN/GaN heterostructures were grown on sapphire substrates by low-pressure metal organic chemical vapor deposition. The influences of NH3 flux and growth temperature on the In composition and morphologies of the lnA...InAlN/GaN heterostructures were grown on sapphire substrates by low-pressure metal organic chemical vapor deposition. The influences of NH3 flux and growth temperature on the In composition and morphologies of the lnAlN were investigated by X-ray diffraction and atomic force microscopy. It＇s found that the In composition increases quickly with NH3 flux decrease. But it＇s not sensitive to NH3 flux under higher flux. This suggests that lower NH3 flux induces a higher growth rate and an enhanced In incorporation. The In composition also increases with the growth temperatures decreasing, and the defects of the InAlN have close relation with In composition. Unstrained lnAlN with In composition of 17% is obtained at NH3 flux of 500 sccm and growth temperature of 790 ℃. The InAlN/GaN heterostructure high electron mobility transistor sample showed a high two-dimensional electron gas （2DEG） mobility of 1210 cm2/（V.s） with the sheet density of 2.3 × 10^13 cm^-2 at room temperature.展开更多
C(CO)–alkyl bonds are ubiquitous in a variety of organic molecules,and their selective activation and functionalization are important for the reconstruction of simple ketones into valuable building blocks.However,due...C(CO)–alkyl bonds are ubiquitous in a variety of organic molecules,and their selective activation and functionalization are important for the reconstruction of simple ketones into valuable building blocks.However,due to the thermodynamic and kinetic stability,the cleavage and transformation of the unstrained C(CO)–alkyl bonds remain a significant challenge.Herein,we report a novel silver-catalyzed scission of the unstrained C(CO)–alkyl bond of ketones by reacting with N-isocyanoiminotriphenylphosphorane(NIITP)under mild conditions.This method could transform a variety of unstrained ketones into iminophosphoranes and nitriles in high yields.Experimental and computational studies disclosed the reaction proceeded through an unprecedented[3+2]/retro-[3+2]cycloaddition mechanism.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.22001147,22371171)Taishan Scholars Project of Shandong Province(No.tsqn202103027)+1 种基金Distinguished Young Scholars of Shandong Province(Overseas)(No.2022HWYQ-001)Qilu Youth Scholar Funding of Shandong University。
文摘The carbon-carbon bond is the one of the most fundamental and abundant bonds that exist in organic molecules,and the challenge of functionalization of carbon-carbon bond has always been a critical pursuit in organic synthesis.In recent years,there have been a growing number of studies on the C-C bond activation.Nevertheless,the metal-catalyzed cleavage of the C-C(O)bond in unstrained ketones has remained relatively underexplored due to the strong affinity of carbonyl groups for metals.In this study,we report a nickel-catalyzed strategy for the reductive alkynylation of ketoimines viaβ-carbon elimination.This method involves the conversion of aryl ketones into aryl ketoimines,thus expanding the toolbox of aryl electrophiles.The use of a N-heterocyclic carbene(NHC)ligand is crucial for this catalytic transformation.This discovery leads to a cross electrophile coupling reaction characterized by its operational simplicity,unique chemo-selectivity and excellent functional group tolerance.In addition,the approach has been effectively applied to the late-stage alkynylation of diverse pharmaceuticals.Ultimately,a series of comprehensive experiments and theoretical studies were conducted to provide insights into the reaction pathway,which supports the proposedβ-carbon elimination process.
基金supported by the Shanghai Institute of Materia Medica,the Chinese Academy of ScienceseNational Natural Science Foundation of China(21772211,21920102003)+4 种基金the Institutes for Drug Discovery and Development,Chinese Academy of Sciences(CASIMM0120163006)the Science and Technology Commission of Shanghai Municipality(17JC1405000,18431907100)the Program of Shanghai Academic Research Leader(19XD1424600)the National Science&Technology Major Project“Key New Drug Creation and Manufacturing Program”,China(2018ZX09711002-006)the China Postdoctoral Science Foundation(2019M662854)
文摘C-C bond activation has emerged as a powerful tool for the construction of complex molecules.Herein,we report a dual ligands relay-promoted transformation of unstrained aryl,alkenyl and alkynyl ketones to the corresponding polyfluoroarenes and nitriles via C-C(=O)bond cleavage and subsequent decarboxylative arylation process.Various polyfluoroarene and nitrile products are obtained in one pot under cyanide-free conditions.The protocol features high atom economy,broad functional group tolerance and excellent heterocyclic compatibility.The late-stage functionalization of the drug and natural product demonstrated the synthetic utility of our protocol.Furthermore,the decisive role of the dual ligands was clarified and the mechanistic rationale including theβ-C elimination as the rate-limiting step was supported by detailed density functional theory(DFT)studies.
基金supported by the National Natural Science Foundation of China(No.61306113)
文摘InAlN/GaN heterostructures were grown on sapphire substrates by low-pressure metal organic chemical vapor deposition. The influences of NH3 flux and growth temperature on the In composition and morphologies of the lnAlN were investigated by X-ray diffraction and atomic force microscopy. It＇s found that the In composition increases quickly with NH3 flux decrease. But it＇s not sensitive to NH3 flux under higher flux. This suggests that lower NH3 flux induces a higher growth rate and an enhanced In incorporation. The In composition also increases with the growth temperatures decreasing, and the defects of the InAlN have close relation with In composition. Unstrained lnAlN with In composition of 17% is obtained at NH3 flux of 500 sccm and growth temperature of 790 ℃. The InAlN/GaN heterostructure high electron mobility transistor sample showed a high two-dimensional electron gas （2DEG） mobility of 1210 cm2/（V.s） with the sheet density of 2.3 × 10^13 cm^-2 at room temperature.
基金provided by the National Natural Science Foundation of China(21871043,21961130376)Department of Science and Technology of Jilin Province(20180101185JC,20190701012GH,20200801065GH)the Fundamental Research Funds for the Central Universities(2412019ZD001,2412019FZ006)。
文摘C(CO)–alkyl bonds are ubiquitous in a variety of organic molecules,and their selective activation and functionalization are important for the reconstruction of simple ketones into valuable building blocks.However,due to the thermodynamic and kinetic stability,the cleavage and transformation of the unstrained C(CO)–alkyl bonds remain a significant challenge.Herein,we report a novel silver-catalyzed scission of the unstrained C(CO)–alkyl bond of ketones by reacting with N-isocyanoiminotriphenylphosphorane(NIITP)under mild conditions.This method could transform a variety of unstrained ketones into iminophosphoranes and nitriles in high yields.Experimental and computational studies disclosed the reaction proceeded through an unprecedented[3+2]/retro-[3+2]cycloaddition mechanism.
