Fifty-three samples of multi-substituted benzylideneanilines XArCH=NArYs （abbreviated XBAYs） were synthesized and their NMR spectra were determined. An extensional study of substituent effects on the 1H NMR chemical...Fifty-three samples of multi-substituted benzylideneanilines XArCH=NArYs （abbreviated XBAYs） were synthesized and their NMR spectra were determined. An extensional study of substituent effects on the 1H NMR chemical shifts （δH（CH=N）） and 13C NMR chemical shifts （δc（CH=N）） of the CH=N bridging group from di-substituted to multi-substituted XBAYs was made based on a total of 182 samples of XBAYs, together with the NMR data of other 129 samples of di-substituted XBAYs quoted from literatures. The results show thatthe substituent specific cross-interaction effect parameter （△（∑σ）2） plays an important role in quantifying the δc（CH=N） values of XBAYs, but it is negligible for quantifying the δH （CH=N） values; the other substituent parameters also present different influences on the δc （CH=N） and （δH （CH=N）. On the whole, the contributions of X and Y to the δc （CH=N） of XBAYs are balanced, but the δH（CH=N） values of XBAYs mainly rely on the contributions of X.展开更多
In this study, a new zirconium-mediated cycloaddition for preparing dibenzosilole derivatives was developed using siliconbridged diynes and electron-withdrawing alkynes as starting materials. The preparation of silico...In this study, a new zirconium-mediated cycloaddition for preparing dibenzosilole derivatives was developed using siliconbridged diynes and electron-withdrawing alkynes as starting materials. The preparation of silicon-bridged diynes from 1-bromide-2-iodobenzene, terminal alkynes, and dimethyldichlorosilane was also studied. Unlike in the previous synthesis methods, much higher yields of electron-withdrawing group-substituted dibenzosilole derivatives were obtained. In addition, a new synthesis strategy for preparing benzonaphthosilole derivatives using internal alkynes, 1,4-dibromobenzene, and electron-withdrawing alkynes as starting materials is proposed. Compared with previous methods, alkyl, phenyl, and electron-withdrawing groups can be successfully introduced onto aromatic rings, and the positions of these substituents can be easily controlled. The cycloaddition reactions for dibenzosilole and benzonaphthosilole derivatives are highly efficient one-pot processes, and the raw materials are available and easily prepared. Using these new methods, a series of novel multisubstituted dibenzonsilole and benzonaphthosilole derivatives were obtained effectively.展开更多
Transition metal-catalyzed olefination of aryl C-H bond is a powerful tool for the synthesis of alkenes. While the Pd-catalyzed oxidative C-H olefination of arenes, also known as Fujiwara-Moritani reaction, has been e...Transition metal-catalyzed olefination of aryl C-H bond is a powerful tool for the synthesis of alkenes. While the Pd-catalyzed oxidative C-H olefination of arenes, also known as Fujiwara-Moritani reaction, has been established as one of the most efficient methods, the substrates are largely limited to terminal olefins with electron-withdrawing group(s). Herein, we report a synergistic silver-mediated and palladium-catalyzed non-directed C-H olefination of arenes with vinyl(pseudo)halides, which offers a complementary strategy to the typical Fujiwara-Moritani reaction. The reactions proceeded well for a variety of halogenated arenes, heteroarenes, and olefin substrates, providing an efficient access to various multi-substituted aryl olefins, including trisubstituted/tetrasubstituted olefins and several complex olefins derived from medicines or natural products. Mechanistic studies indicated a bimetallic Pd/Ag cooperation is operative in the catalysis, i.e., the reaction is initiated by aryl C-H bond cleavage via ligation with phosphine/Ag species, followed by transferring of the aryl moiety to a vinyl palladium intermediate,which is in turn formed by oxidative addition of vinyl(pseudo)halide to a Pd complex. This method enables the synthesis of a wide range of challenging multi-substituted vinyl products from simple arenes(directing-group free) in a streamlined and controllable fashion.展开更多
The ruthenium multi-substituted polyoxotungstate,K_(7)[Si W_(9)O_(37)Ru_(4)(H_(2)O)_(3)Cl_(3)]·15H_(2)O(S1),was synthesized by a conventional aqueous solution containing the trilacunary Keggin-anionsβ-Na_(9)HSi ...The ruthenium multi-substituted polyoxotungstate,K_(7)[Si W_(9)O_(37)Ru_(4)(H_(2)O)_(3)Cl_(3)]·15H_(2)O(S1),was synthesized by a conventional aqueous solution containing the trilacunary Keggin-anionsβ-Na_(9)HSi W_(9)O_(34)·12H_(2)O(S2)and Ru Cl_(3)·n H_(2)O(S3).Compound S1 was charac‐terized by elemental analysis,energy-dispersive X-ray spectroscopy(EDS),thermogravimetric analysis(TG),infrared spectroscopy(IR),uliraviolet visible absorption spectroscopy(UV/Vis)and X-ray photoelectron spectroscopy(XPS).The cytotoxicitycy of S1 was tested in C33A(human cervical cancer),DLD-1(human colon cancer),Hep G2(human liver cancer)and human normal embryonic lung fibroblasts cell(MRC-5).And the viability of these treated cells was evaluated by MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bro‐mide)assay.To explore the mode of cell death induced by S1,morphological study of DNA damage and apoptosis assays were conducted.These analyses revealed that S1 exerted its cytotoxic effect in a dose-dependent manner,primarily triggering apoptotic cell death.Cell cycle analysis by flow cytometry indicated that compound S1 caused cell cycle arrest and accumulated cells in S phase.展开更多
The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed...The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed.This protocol was applied efficiently in the aqueous synthesis of multi-substituted vinylboranes.展开更多
Herein,we report a distinctive and marvelous dual-migration of alkynyl tetracoordinate borons activated by both hydrochloric acid(HCl)and N-chlorosuccinimide(NCS),which is significantly different from conventional mig...Herein,we report a distinctive and marvelous dual-migration of alkynyl tetracoordinate borons activated by both hydrochloric acid(HCl)and N-chlorosuccinimide(NCS),which is significantly different from conventional migration modes under basic conditions.In this protocol,HCl,as the first electrophile,activates the C≡C bond,triggering the first 1,2-aryl migration.Subsequently,NCS promotes a secondary metallate shift,enabling the construction of polysubstituted alkenes.Notably,this process can work well under mild conditions,exhibits high efficiency,and provides valuable products.This transformation reveals that Zweifel olefination is not just limited to traditional basic conditions,it can proceed smoothly under acidic conditions as well,which greatly expands the scope of this well-known olefination reaction.展开更多
基金supported by the National Natural Science Foundation of China(No.21672058 and No.21272063)
文摘Fifty-three samples of multi-substituted benzylideneanilines XArCH=NArYs （abbreviated XBAYs） were synthesized and their NMR spectra were determined. An extensional study of substituent effects on the 1H NMR chemical shifts （δH（CH=N）） and 13C NMR chemical shifts （δc（CH=N）） of the CH=N bridging group from di-substituted to multi-substituted XBAYs was made based on a total of 182 samples of XBAYs, together with the NMR data of other 129 samples of di-substituted XBAYs quoted from literatures. The results show thatthe substituent specific cross-interaction effect parameter （△（∑σ）2） plays an important role in quantifying the δc（CH=N） values of XBAYs, but it is negligible for quantifying the δH （CH=N） values; the other substituent parameters also present different influences on the δc （CH=N） and （δH （CH=N）. On the whole, the contributions of X and Y to the δc （CH=N） of XBAYs are balanced, but the δH（CH=N） values of XBAYs mainly rely on the contributions of X.
基金supported by the National Natural Science Foundation of China(No.21102099)
文摘In this study, a new zirconium-mediated cycloaddition for preparing dibenzosilole derivatives was developed using siliconbridged diynes and electron-withdrawing alkynes as starting materials. The preparation of silicon-bridged diynes from 1-bromide-2-iodobenzene, terminal alkynes, and dimethyldichlorosilane was also studied. Unlike in the previous synthesis methods, much higher yields of electron-withdrawing group-substituted dibenzosilole derivatives were obtained. In addition, a new synthesis strategy for preparing benzonaphthosilole derivatives using internal alkynes, 1,4-dibromobenzene, and electron-withdrawing alkynes as starting materials is proposed. Compared with previous methods, alkyl, phenyl, and electron-withdrawing groups can be successfully introduced onto aromatic rings, and the positions of these substituents can be easily controlled. The cycloaddition reactions for dibenzosilole and benzonaphthosilole derivatives are highly efficient one-pot processes, and the raw materials are available and easily prepared. Using these new methods, a series of novel multisubstituted dibenzonsilole and benzonaphthosilole derivatives were obtained effectively.
基金supported by the National Key R&D Program of China(2021YFA1500100)the National Natural Science Foundation of China(21821002,92256303,22171278)+1 种基金Shanghai Science and Technology Committee(23ZR1482400)the Natural Science Foundation of Ningbo(2023J034)。
文摘Transition metal-catalyzed olefination of aryl C-H bond is a powerful tool for the synthesis of alkenes. While the Pd-catalyzed oxidative C-H olefination of arenes, also known as Fujiwara-Moritani reaction, has been established as one of the most efficient methods, the substrates are largely limited to terminal olefins with electron-withdrawing group(s). Herein, we report a synergistic silver-mediated and palladium-catalyzed non-directed C-H olefination of arenes with vinyl(pseudo)halides, which offers a complementary strategy to the typical Fujiwara-Moritani reaction. The reactions proceeded well for a variety of halogenated arenes, heteroarenes, and olefin substrates, providing an efficient access to various multi-substituted aryl olefins, including trisubstituted/tetrasubstituted olefins and several complex olefins derived from medicines or natural products. Mechanistic studies indicated a bimetallic Pd/Ag cooperation is operative in the catalysis, i.e., the reaction is initiated by aryl C-H bond cleavage via ligation with phosphine/Ag species, followed by transferring of the aryl moiety to a vinyl palladium intermediate,which is in turn formed by oxidative addition of vinyl(pseudo)halide to a Pd complex. This method enables the synthesis of a wide range of challenging multi-substituted vinyl products from simple arenes(directing-group free) in a streamlined and controllable fashion.
基金Supported by the National Natural Science Foundation of China (21701120)the Science and Technology Innovation Project of Colleges and Universities in Shanxi Province (2020L0334)the Innovation and Entrepreneurship Training Program for College Students in Shanxi Province(20240778)。
文摘The ruthenium multi-substituted polyoxotungstate,K_(7)[Si W_(9)O_(37)Ru_(4)(H_(2)O)_(3)Cl_(3)]·15H_(2)O(S1),was synthesized by a conventional aqueous solution containing the trilacunary Keggin-anionsβ-Na_(9)HSi W_(9)O_(34)·12H_(2)O(S2)and Ru Cl_(3)·n H_(2)O(S3).Compound S1 was charac‐terized by elemental analysis,energy-dispersive X-ray spectroscopy(EDS),thermogravimetric analysis(TG),infrared spectroscopy(IR),uliraviolet visible absorption spectroscopy(UV/Vis)and X-ray photoelectron spectroscopy(XPS).The cytotoxicitycy of S1 was tested in C33A(human cervical cancer),DLD-1(human colon cancer),Hep G2(human liver cancer)and human normal embryonic lung fibroblasts cell(MRC-5).And the viability of these treated cells was evaluated by MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bro‐mide)assay.To explore the mode of cell death induced by S1,morphological study of DNA damage and apoptosis assays were conducted.These analyses revealed that S1 exerted its cytotoxic effect in a dose-dependent manner,primarily triggering apoptotic cell death.Cell cycle analysis by flow cytometry indicated that compound S1 caused cell cycle arrest and accumulated cells in S phase.
文摘The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed.This protocol was applied efficiently in the aqueous synthesis of multi-substituted vinylboranes.
基金the financial support from the National Key Research&Development Program of China(2023YFF0723900)the National Natural Science Foundation of China(22271105)+3 种基金the Natural Science Foundation of Fujian Province(2022J02009)the Open Research Fund of State Key Laboratory of Coordination ChemistrySchool of Chemistry and Chemical Engineering,Nanjing Universitythe Hubei Key Laboratory of Pollutant Analysis&Reuse Technology Open Foundation(PA240102)。
文摘Herein,we report a distinctive and marvelous dual-migration of alkynyl tetracoordinate borons activated by both hydrochloric acid(HCl)and N-chlorosuccinimide(NCS),which is significantly different from conventional migration modes under basic conditions.In this protocol,HCl,as the first electrophile,activates the C≡C bond,triggering the first 1,2-aryl migration.Subsequently,NCS promotes a secondary metallate shift,enabling the construction of polysubstituted alkenes.Notably,this process can work well under mild conditions,exhibits high efficiency,and provides valuable products.This transformation reveals that Zweifel olefination is not just limited to traditional basic conditions,it can proceed smoothly under acidic conditions as well,which greatly expands the scope of this well-known olefination reaction.
