A soluble, poly(ethylene glycol)-supported piperazine catalyst was prepared. This soluble catalyst efficiently catalyzes the Knoevenagel condensation of various aromatic aldehydes with diethyl malonate or ethyl acet...A soluble, poly(ethylene glycol)-supported piperazine catalyst was prepared. This soluble catalyst efficiently catalyzes the Knoevenagel condensation of various aromatic aldehydes with diethyl malonate or ethyl acetoacetate in a homogeneous phase to afford the desired alkenes in good purity and yield with a facile work-up process. It was found that the polymer reagent could be repeatedly used at least four times without the too much loss of activity. The catalyst has shown a good activity, stability, and recycling capability.展开更多
A silver-catalyzed,K_(2)S_(2)O_(8)-mediated protocol to access regioselective acylarylation of unactivated alkenes was developed.The reaction between N-allyl-indoles andα-oxocarboxylic acids proceeded smoothly and in...A silver-catalyzed,K_(2)S_(2)O_(8)-mediated protocol to access regioselective acylarylation of unactivated alkenes was developed.The reaction between N-allyl-indoles andα-oxocarboxylic acids proceeded smoothly and involved an acyl radical addition/C–H cyclization cascade.The protocol showed a broad substrate scope and good tolerance of functional groups.The reaction proceeded with both internal and terminal alkenes to furnish many functional pyrrolo[1,2-a]indoles bearing the ketone carbonyl group,and this feature also provides the potential to construct structurally complex N-containing heterocycles.展开更多
Seven square planar bis(o-diiminobenzosemiquinonato)nickel(II) complexes, [Ni(o-C6H4(NH)(NAr))2] (Ar= Mes, 1; p-F-C6H4, 2; p-CI-C6H4, 3), [Ni(o-4,5-F2-C6H2(NH)(NPh))2] (4), and [Ni(o-4,5-CIz-C6H2...Seven square planar bis(o-diiminobenzosemiquinonato)nickel(II) complexes, [Ni(o-C6H4(NH)(NAr))2] (Ar= Mes, 1; p-F-C6H4, 2; p-CI-C6H4, 3), [Ni(o-4,5-F2-C6H2(NH)(NPh))2] (4), and [Ni(o-4,5-CIz-C6H2(NH)(NAr))2] (Ar =Ph, 5; 2,6-F2-C6H3, 6; 2,6-C12-C6H3, 7), have been synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, IR, UV-Vis-NIR, elemental analyses, HRMS, as well as single-crystal X-ray diffraction studies (1 and 7). The cyclic voltammograms of these complexes exhibit two reversible redox processes of [NiLe]0n- and [NIL2]l /2 , and one irreversible process of [NiL2]~n+. Substituent effects on the redox properties of these complexes, in addi- tion with those of the known complexes [Ni(o-C6Ha(NH)(NPh))2] (8) and [Ni(o-3,5-Butz-C6Hz(NH)2)2] (9), are identified by comparing the half-wave potentials of the reduction waves, as 1 ~ 9 〈 8 ~ 2 〈 3 〈 4 〈 5 〈 7 〈 6, reflect- ing the ease of reduction of [NIL2] parallels the electron-donating and -withdrawing ability of the substituent group. Reduction of 1 with one or two equivalents of sodium metal in THF has led to the isolation of [Na(THF)3][I] and [Na(THF)3]2[1]. The structure data of these two complexes revealed by low-temperature X-ray crystallography suggest their corresponding electronic structures of [Nill(lL-1 )(IL2-)]1- and [Ni1](1L2 )212-, which are in line with those of [9]n (n = 1-, 2-) suggested by spectroelectrochemical study.展开更多
基金Supported by the National Natural Science Foundation of China(No.20872001)the Natural Science Foundation of Education Administration of Anhui Province,China(No.KJ2008A064)
文摘A soluble, poly(ethylene glycol)-supported piperazine catalyst was prepared. This soluble catalyst efficiently catalyzes the Knoevenagel condensation of various aromatic aldehydes with diethyl malonate or ethyl acetoacetate in a homogeneous phase to afford the desired alkenes in good purity and yield with a facile work-up process. It was found that the polymer reagent could be repeatedly used at least four times without the too much loss of activity. The catalyst has shown a good activity, stability, and recycling capability.
基金the National Natural Science Foundation of China(21702237,21272004)the Natural Science Research Project for Anhui Universities,the Start-up Research Fund of Anhui Normal University and the Project for Students’Innovative Experiment of Anhui Normal University for their financial support.
文摘A silver-catalyzed,K_(2)S_(2)O_(8)-mediated protocol to access regioselective acylarylation of unactivated alkenes was developed.The reaction between N-allyl-indoles andα-oxocarboxylic acids proceeded smoothly and involved an acyl radical addition/C–H cyclization cascade.The protocol showed a broad substrate scope and good tolerance of functional groups.The reaction proceeded with both internal and terminal alkenes to furnish many functional pyrrolo[1,2-a]indoles bearing the ketone carbonyl group,and this feature also provides the potential to construct structurally complex N-containing heterocycles.
基金We thank the financial supports from the National Natural Science Foundation of China,the Science and Technology Commission of Shanghai Municipality
文摘Seven square planar bis(o-diiminobenzosemiquinonato)nickel(II) complexes, [Ni(o-C6H4(NH)(NAr))2] (Ar= Mes, 1; p-F-C6H4, 2; p-CI-C6H4, 3), [Ni(o-4,5-F2-C6H2(NH)(NPh))2] (4), and [Ni(o-4,5-CIz-C6H2(NH)(NAr))2] (Ar =Ph, 5; 2,6-F2-C6H3, 6; 2,6-C12-C6H3, 7), have been synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, IR, UV-Vis-NIR, elemental analyses, HRMS, as well as single-crystal X-ray diffraction studies (1 and 7). The cyclic voltammograms of these complexes exhibit two reversible redox processes of [NiLe]0n- and [NIL2]l /2 , and one irreversible process of [NiL2]~n+. Substituent effects on the redox properties of these complexes, in addi- tion with those of the known complexes [Ni(o-C6Ha(NH)(NPh))2] (8) and [Ni(o-3,5-Butz-C6Hz(NH)2)2] (9), are identified by comparing the half-wave potentials of the reduction waves, as 1 ~ 9 〈 8 ~ 2 〈 3 〈 4 〈 5 〈 7 〈 6, reflect- ing the ease of reduction of [NIL2] parallels the electron-donating and -withdrawing ability of the substituent group. Reduction of 1 with one or two equivalents of sodium metal in THF has led to the isolation of [Na(THF)3][I] and [Na(THF)3]2[1]. The structure data of these two complexes revealed by low-temperature X-ray crystallography suggest their corresponding electronic structures of [Nill(lL-1 )(IL2-)]1- and [Ni1](1L2 )212-, which are in line with those of [9]n (n = 1-, 2-) suggested by spectroelectrochemical study.