The dihydric dithioketenes 3a-c obtained by 1,2-addition of methallyl Grignard reagent to bis(alkylthio)methylidene derivative ofdimedone 2a-c wewr converted to the cycloaromatization product 4 assisted by boron trifl...The dihydric dithioketenes 3a-c obtained by 1,2-addition of methallyl Grignard reagent to bis(alkylthio)methylidene derivative ofdimedone 2a-c wewr converted to the cycloaromatization product 4 assisted by boron trifluoride etherate.When this reaction was performed in methanol,the substitution-cycloaroatization product 5 was obtained as by- product from 3c.To this eycloaromatization reaction,,the reactivity order dimethylthio>1, 3 - propylenedithio>1, 2- ethylenedithio carbon cation was established by the yields from 3a-c 4.An intramolecular a1,a1reaction pattern was developed by experiment.展开更多
A mild and efficient n Bu4 NBr-mediated oxidative cycloaromatization to prepareβ-carbolines from readily available tryptophans and aldehydes is described.The reaction is practical and allows the synthesis ofβ-carbol...A mild and efficient n Bu4 NBr-mediated oxidative cycloaromatization to prepareβ-carbolines from readily available tryptophans and aldehydes is described.The reaction is practical and allows the synthesis ofβ-carbolines on gram-scale.Some of products crystallized from the reaction mixture and were easily removed by filtration,obviating the need for chromatographic separation.展开更多
Bergman cyclization has shown great promise in constructing conjugated polymers. However, the application of this reaction in polymer science is still limited due to the harsh reaction condition and ill-defined struct...Bergman cyclization has shown great promise in constructing conjugated polymers. However, the application of this reaction in polymer science is still limited due to the harsh reaction condition and ill-defined structure of the achieved polymers. To this end, the cycloaromatization polymerization of enediynes catalyzed by a series of transition metal catalysts is investigated in this work, by taking advantage of the coordination chemistry of the enediyne with the transition metal complexes. According to the nuclear magnetic resonance（NMR）, Fourier transform infrared（FTIR）, ultraviolet-visble（UV-Vis） spectroscopies and matrix-assisted laser desorption/ionization time-offlight mass spectrometry（MALDI-TOF MS） analysis, the cycloaromatization polymerization of enediynes proceeds under milder conditions and in a more controlled manner in the presence of palladium（II） complexes, giving structurally regulated conjugated polymers in high yields.展开更多
文摘The dihydric dithioketenes 3a-c obtained by 1,2-addition of methallyl Grignard reagent to bis(alkylthio)methylidene derivative ofdimedone 2a-c wewr converted to the cycloaromatization product 4 assisted by boron trifluoride etherate.When this reaction was performed in methanol,the substitution-cycloaroatization product 5 was obtained as by- product from 3c.To this eycloaromatization reaction,,the reactivity order dimethylthio>1, 3 - propylenedithio>1, 2- ethylenedithio carbon cation was established by the yields from 3a-c 4.An intramolecular a1,a1reaction pattern was developed by experiment.
基金National Natural Science Foundation of China (Nos. 21172120 and 21472093)Tianjin Municipal Science and Technology Commission (No. 14JCYBJC20600) for financial support
文摘A mild and efficient n Bu4 NBr-mediated oxidative cycloaromatization to prepareβ-carbolines from readily available tryptophans and aldehydes is described.The reaction is practical and allows the synthesis ofβ-carbolines on gram-scale.Some of products crystallized from the reaction mixture and were easily removed by filtration,obviating the need for chromatographic separation.
基金financially supported by the National Natural Science Foundation of China (No. 21474027)Shanghai Leading Academic Discipline Project (No. B502)the "Eastern Scholar Professorship" support from Shanghai local government
文摘Bergman cyclization has shown great promise in constructing conjugated polymers. However, the application of this reaction in polymer science is still limited due to the harsh reaction condition and ill-defined structure of the achieved polymers. To this end, the cycloaromatization polymerization of enediynes catalyzed by a series of transition metal catalysts is investigated in this work, by taking advantage of the coordination chemistry of the enediyne with the transition metal complexes. According to the nuclear magnetic resonance（NMR）, Fourier transform infrared（FTIR）, ultraviolet-visble（UV-Vis） spectroscopies and matrix-assisted laser desorption/ionization time-offlight mass spectrometry（MALDI-TOF MS） analysis, the cycloaromatization polymerization of enediynes proceeds under milder conditions and in a more controlled manner in the presence of palladium（II） complexes, giving structurally regulated conjugated polymers in high yields.
