High catalytic efficiencies in ring opening polymerization(ROP)of a large ring-sized macrolactone,ω-pentadecalactone(PDL),by using transition metal Fe(II)-based catalysts were achieved for the first time in this stud...High catalytic efficiencies in ring opening polymerization(ROP)of a large ring-sized macrolactone,ω-pentadecalactone(PDL),by using transition metal Fe(II)-based catalysts were achieved for the first time in this study.Benefited from the bulky nature of the ligatedα-diimine ligands,as evidenced from single-crystal structures,as well as the weakly oxophilic nature of the metal centers,chain transesterification reactions could be partially suppressed,allowing the polymerization proceed in a living-like and semi-controllable manner,i.e.good linear dependence of propagation rates on catalyst concentration and PDL concentration as observed in the detailed kinetics studies.The whole polymerization proceeds via a“coordination-insertion”mechanism,and with the aid of density functional theory(DFT)calculation studies,a“slow insertion→fast elimination”manner was demonstrated for the monomer propagation step,suggesting the insertion of Fe-OR into the carbonyl group C=O as the rate-determining step.The present catalytic system also showed fast chain transfer reactions to alcohol compounds,affording quasi-immortal characteristics.DFT calculations showed that such a transfer reaction only required an energy barrier of 6.4 kcal/mol,performing a good consistency with the fast chain transfer rates.展开更多
A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-...A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Metal(Al,Ti,Zr)triflate grafted mesoporous SBA‐15(AlTf/S,TiTf/S,ZrTf/S)samples were synthesizedas inexpensive solid acid materials by a simple one‐pot‐two‐step synthesis methodology.These materials were characteri...Metal(Al,Ti,Zr)triflate grafted mesoporous SBA‐15(AlTf/S,TiTf/S,ZrTf/S)samples were synthesizedas inexpensive solid acid materials by a simple one‐pot‐two‐step synthesis methodology.These materials were characterized by X‐ray diffraction,N2‐sorption,thermogravimetric analysis,Fourier transform infrared spectroscopy(FT‐IR),in‐situ pyridine FT‐IR spectroscopy,and elementalanalysis.ZrTf/S was found to be a highly efficient and reusable solid acid catalyst for ring opening ofepoxides with amines and alcohols and producedβ‐amino alcohols andβ‐alkoxy alcohols respectivelyunder ambient reaction conditions.The ZrTf/S catalyst showed the highest activity,whichwas attributed to its high acidity compared with that of the Ti and Al containing samples.展开更多
Ring opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO)was successfully carried out by using a series of aluminum-based catalyst in 1,4-dioxane at62±2℃. The results showed that in-situ ...Ring opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO)was successfully carried out by using a series of aluminum-based catalyst in 1,4-dioxane at62±2℃. The results showed that in-situ AlR_3-H_2O (R=ethyl, iso-butyl) catalysts gavehigher molecular weight (M_w～10~4), while Al(OR)_3 catalysts gave the higher alternatingcopolymer structure with slightly lower molecular weight. The in-situ AlR_3-H_2O systemshave been evaluated in more detail for the reaction which showed the optimum H_2O/Almolar ratio to be 0.5. The copolymers with different composition (F_(SA)/F_(EO)= 36/64to 45/55 mol/mol) were synthesized by using different monomer feed ratio. The melt-ing point (T_m), glass transition temperature (T_g) and enthalpy of fusion (ΔH_f) of thesecopolymers are depended on the copolymer composition and in the range of 87～102℃,-12～-18℃, and 37～66J/g, respectively. The second heating scan of DSC also in-dicated that the higher alternating copolymer was more easily recrystallized. The onsetdecomposition temperature was more than 300℃ under nitrogen and influenced by thecopolymer composition.展开更多
A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead o...A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead oxygen with a piperazine's derivatives, which proceeds with very high regioselectivity.展开更多
The random copolymers of glutamic acid （LG） and aspartic acid （ASP）, poly（LG-co-ASP）, with designed compositions could be successfully synthesized via combination of N-carboxyanhydride ring opening copolymerizat...The random copolymers of glutamic acid （LG） and aspartic acid （ASP）, poly（LG-co-ASP）, with designed compositions could be successfully synthesized via combination of N-carboxyanhydride ring opening copolymerization with debenzylation. Ring opening copolymerizations of y：benzyl-L-glutamate N-carboxyanhydride （BLG-NCA） and β-benzyl-Laspartate N-carboxyanhydride （BLA-NCA） were carried out by using different amines including triethylamine （TEA）, diethylamine, n-hexylamine （NHA）, triphenylamine, diphenylamine or aniline as initiators. All the 6 amines were highly efficient to get well-defined poly（BLG-co-BLA） copolymers with designed compositions although the polymerizations proceeded via different mechanisms （normal amine mechanism or/and activated monomer mechanism）, which are based on chemical structure of amines. The molecular weights of poly（BLG-co-BLA） copolymers could be mediated by both TEA concentration and polymerization time. Then, debenzylation ofpoly（BLG-co-BLA） copolymers was conducted to prepare the corresponding hydrophilic random eopolymers of poly（LG-co-ASP） with a-subunit structure in ASP structural units. The contents of LG structural units in poly（LG-co-ASP） copolymers matched with those of BLG-NCA in NCA-monomer feeds in ring opening copolymerizations initiated by NHA or TEA and were closed to the theoretical line. The diblock copolymer of poly（BLG-b-BLA） could also be synthesized via living NCA ring opening copolymerization by sequential addition of BLG- NCA and BLA-NCA.展开更多
For the first time,metal hydrogen sulfates and phosphates/silica gel have been studied as efficient and powerful solid acid catalysts in the ring opening of epoxides with thiocyanate anion.The most significant result ...For the first time,metal hydrogen sulfates and phosphates/silica gel have been studied as efficient and powerful solid acid catalysts in the ring opening of epoxides with thiocyanate anion.The most significant result was obtained by Al(HSO4)3/SiO2which afforded the corresponding β-hydroxy thiocyanates under mild reaction conditions and in very short reaction times.The cheapness, availability of the catalyst,ease of procedure and work-up make this method attractive for the organic synthesis.展开更多
Ligand effect of the catalytic system WCl6-Et2AlCl for ring opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD) was investigated. The experimental results show that adding sterically hindered phenol-2...Ligand effect of the catalytic system WCl6-Et2AlCl for ring opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD) was investigated. The experimental results show that adding sterically hindered phenol-2. 6-di-tert-butylcresylol(DTBC) in the catalytic system not only can obviously increase the monomer conversion of polymerization but also improve the mechanical properties, such as notched impact strength (NIS), tensile strength (TS) ect. 5 of the synthesized polyicycolpentadiene (PDCPD). A similar effect can be observed by using a sterically hindered polymeric phenol - linear phenol formaldehyde resin (LPF) as a ligand.展开更多
A rhodium-catalyzed ring opening reaction of N-Boc-azabenzonorbornadiene with heteroatom nucleophiles was described. Piperidine and piperazine＇s derivatives were nucleophiles in this reaction. The yields of the produ...A rhodium-catalyzed ring opening reaction of N-Boc-azabenzonorbornadiene with heteroatom nucleophiles was described. Piperidine and piperazine＇s derivatives were nucleophiles in this reaction. The yields of the products 2a-f are good and the regioselectivity are excellent.展开更多
The cationic ring-opening polymerization of tetrahydrofiiran using maghnite-H~＋ is reported.Maghnite-H~＋,is a non-toxic solid catalyst issued from proton exchanged montmorillonite clay.Polytetrahydrofuran,also call...The cationic ring-opening polymerization of tetrahydrofiiran using maghnite-H~＋ is reported.Maghnite-H~＋,is a non-toxic solid catalyst issued from proton exchanged montmorillonite clay.Polytetrahydrofuran,also called ＂poly（butandiol） ether＂,with acetate and hydroxyl end groups was successfully synthesized.Effects of reaction temperature, weight ratio of initiator/monomer and reaction time on the conversion of monomer and on the molecular weight are investigated.A cationic mechanism of the reaction was proposed.This chemistry can be considered as a suitable route for preparing poly（THF） as a soft segment for thermoplastic elastomers.展开更多
Allylic amines and 1,3-oxazinanes are valuable molecular skeletons in organic synthesis and pharmaceutical industry.A straightforward way to such two types of compounds by solvent-controlled rare-earth metal Lewis aci...Allylic amines and 1,3-oxazinanes are valuable molecular skeletons in organic synthesis and pharmaceutical industry.A straightforward way to such two types of compounds by solvent-controlled rare-earth metal Lewis acid-catalyzed transformations of 2-(hetero)aryl-N-sulfonylazetidines:the ring-opening isomerization of azetidines to allylic amines and the annulation of azetidines with aldehydes to 1,3-oxazinanes are reported.These two reactions feature scalability,low catalyst loading,mild reaction conditions,excellent yields and regioselectivity with demonstrated utility in three-step product transformations to naftifine,abamine and abamine SG.展开更多
A new kind of polyesteramide based on 3-morpholinone and e caprolactone was synthesized by ring opening polymerization with zinc powder as catalyst.The polymer was characterized by^(1)H NMR,GPC and FT-IR.The effect of...A new kind of polyesteramide based on 3-morpholinone and e caprolactone was synthesized by ring opening polymerization with zinc powder as catalyst.The polymer was characterized by^(1)H NMR,GPC and FT-IR.The effect of time,temperature and ratio of m(M)/m(1),n(M)/n(CL)on the reaction was studied.The results show that the optimal reaction temperature is 120℃;the optimal duration of reaction is 24 h;the optimal ratio of m(M)/m(CL)is 50:1;the optimal ratio of n(M)/n(CL)is 1:2.Under the optimal condition the polymer whose M_(n)was 13509 could be obtained while the weight yield was 79%.展开更多
We have developed an asymmetric ring opening reaction of oxabenzonorbornadienes with substituted phenolic nucleophiles. Under the reaction conditions （ [Rh（COD）C1]2 （1 mol%）, （S）-（R）-PPF-P^Bu2 （2 mol%）, THF...We have developed an asymmetric ring opening reaction of oxabenzonorbornadienes with substituted phenolic nucleophiles. Under the reaction conditions （ [Rh（COD）C1]2 （1 mol%）, （S）-（R）-PPF-P^Bu2 （2 mol%）, THF, reflux）, the reaction products were obtained with high yield and enantiomeric excesses （ up to 99% ee）.展开更多
We have developed an asymmetric ring opening reaction of azabenzonorbornadiene with substituted piperazine. By increasing the amount of catalyst (from 2.5 to 5%) and ligands (5 to 10%) as well as addition of ammonium ...We have developed an asymmetric ring opening reaction of azabenzonorbornadiene with substituted piperazine. By increasing the amount of catalyst (from 2.5 to 5%) and ligands (5 to 10%) as well as addition of ammonium iodide, the products can be obtained in high yield and the reaction time shortened dramatically, but the ee values were rather low.展开更多
An efficient and water tolerant method for the synthesis ofβ-haloamines is described utilizing hydrated nickel（Ⅱ） halides （NiX_2ⅩnH_2O X = Cl,Br,I） and aziridines as starting materials.N-Tosylaziridines reacted...An efficient and water tolerant method for the synthesis ofβ-haloamines is described utilizing hydrated nickel（Ⅱ） halides （NiX_2ⅩnH_2O X = Cl,Br,I） and aziridines as starting materials.N-Tosylaziridines reacted with NiCl_2·6H_2O or NiI_2·6H_2O givingβ-chloro -orβ-iodoamines in high yields（73-99%） within a short time,but 10 mol%of n-Bu_4NBr should be added in the reactions of N-tosylaziridines with NiBr_2·3H_2O in order to obtain the high yields of correspondingβ-bromoamines.Solvent played an important role in the reactions.The proper solvent for the reaction of NiCl_2·6H_2O was DMF,while NiBr_2·3H_2O or NiI_2·6H_2O proceeded well in 1,4-dioxane.展开更多
A stereoselective and regiospecific synthesis of procursors(2),(4),(6)and(7)of prostacyclin analogues from 2,3-epoxylbicyclo[3.2.0]hept-6-one(1)are described.
Chloromethyl-2-norbornene was synthesized via Diels-Alder reaction of cyclopentadiene and allyl chloride using a polymer supported boron trifluoride as the catalyst, and was then lithiated and used to initiate a livin...Chloromethyl-2-norbornene was synthesized via Diels-Alder reaction of cyclopentadiene and allyl chloride using a polymer supported boron trifluoride as the catalyst, and was then lithiated and used to initiate a living anionic polymerization of styrene to prepare a macromonome, 5-polystyryl-2-norbornene NBPS. Comb graft copolymer PNBgPS was synthesized via ring opening metathesis polymerization of the macromonomer under the catalysis of ruthenium carbene complex RuCl2(PPh3)2(=CCHtBu) and its polymer supported correspondent. Experimental results showed that the behavior of both the supported boron and supported ruthenium catalysts are superior to their unsupported counterparts. The possible promotion mechanism of the tailor-made supports is discussed.展开更多
Visible light photocatalytic redox catalysis has become a powerful tool for organic synthesis, and has opened up new avenues for the formation of challenging structural skeletons and chemical bonds. In this respect, d...Visible light photocatalytic redox catalysis has become a powerful tool for organic synthesis, and has opened up new avenues for the formation of challenging structural skeletons and chemical bonds. In this respect, diverse photocatalysts, including ruthenium(II), iridium(Ⅲ), and organic dyes, have been most commonly applied.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21901020 and 22003076)China Postdoctoral Science Foundation(No.2021M701818)+1 种基金Shandong Provincial Natural Science Foundation(No.ZR2022QE237)the Qingdao Postdoctoral Applied Research Project.H.Liu sincerely acknowledges financial support from the Taishan Scholars Program(No.tsqn202211165)。
文摘High catalytic efficiencies in ring opening polymerization(ROP)of a large ring-sized macrolactone,ω-pentadecalactone(PDL),by using transition metal Fe(II)-based catalysts were achieved for the first time in this study.Benefited from the bulky nature of the ligatedα-diimine ligands,as evidenced from single-crystal structures,as well as the weakly oxophilic nature of the metal centers,chain transesterification reactions could be partially suppressed,allowing the polymerization proceed in a living-like and semi-controllable manner,i.e.good linear dependence of propagation rates on catalyst concentration and PDL concentration as observed in the detailed kinetics studies.The whole polymerization proceeds via a“coordination-insertion”mechanism,and with the aid of density functional theory(DFT)calculation studies,a“slow insertion→fast elimination”manner was demonstrated for the monomer propagation step,suggesting the insertion of Fe-OR into the carbonyl group C=O as the rate-determining step.The present catalytic system also showed fast chain transfer reactions to alcohol compounds,affording quasi-immortal characteristics.DFT calculations showed that such a transfer reaction only required an energy barrier of 6.4 kcal/mol,performing a good consistency with the fast chain transfer rates.
基金the partial support of this work by Shahid Chamran Research Council
文摘A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金supported by the CAS President’s International Fellowship Initiative (2016PT028)the National Natural Science Foundation of China (21273225 and 21403219)~~
文摘Metal(Al,Ti,Zr)triflate grafted mesoporous SBA‐15(AlTf/S,TiTf/S,ZrTf/S)samples were synthesizedas inexpensive solid acid materials by a simple one‐pot‐two‐step synthesis methodology.These materials were characterized by X‐ray diffraction,N2‐sorption,thermogravimetric analysis,Fourier transform infrared spectroscopy(FT‐IR),in‐situ pyridine FT‐IR spectroscopy,and elementalanalysis.ZrTf/S was found to be a highly efficient and reusable solid acid catalyst for ring opening ofepoxides with amines and alcohols and producedβ‐amino alcohols andβ‐alkoxy alcohols respectivelyunder ambient reaction conditions.The ZrTf/S catalyst showed the highest activity,whichwas attributed to its high acidity compared with that of the Ti and Al containing samples.
文摘Ring opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO)was successfully carried out by using a series of aluminum-based catalyst in 1,4-dioxane at62±2℃. The results showed that in-situ AlR_3-H_2O (R=ethyl, iso-butyl) catalysts gavehigher molecular weight (M_w～10~4), while Al(OR)_3 catalysts gave the higher alternatingcopolymer structure with slightly lower molecular weight. The in-situ AlR_3-H_2O systemshave been evaluated in more detail for the reaction which showed the optimum H_2O/Almolar ratio to be 0.5. The copolymers with different composition (F_(SA)/F_(EO)= 36/64to 45/55 mol/mol) were synthesized by using different monomer feed ratio. The melt-ing point (T_m), glass transition temperature (T_g) and enthalpy of fusion (ΔH_f) of thesecopolymers are depended on the copolymer composition and in the range of 87～102℃,-12～-18℃, and 37～66J/g, respectively. The second heating scan of DSC also in-dicated that the higher alternating copolymer was more easily recrystallized. The onsetdecomposition temperature was more than 300℃ under nitrogen and influenced by thecopolymer composition.
文摘A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead oxygen with a piperazine's derivatives, which proceeds with very high regioselectivity.
基金National Natural Science Foundation of China(No.51173008)
文摘The random copolymers of glutamic acid （LG） and aspartic acid （ASP）, poly（LG-co-ASP）, with designed compositions could be successfully synthesized via combination of N-carboxyanhydride ring opening copolymerization with debenzylation. Ring opening copolymerizations of y：benzyl-L-glutamate N-carboxyanhydride （BLG-NCA） and β-benzyl-Laspartate N-carboxyanhydride （BLA-NCA） were carried out by using different amines including triethylamine （TEA）, diethylamine, n-hexylamine （NHA）, triphenylamine, diphenylamine or aniline as initiators. All the 6 amines were highly efficient to get well-defined poly（BLG-co-BLA） copolymers with designed compositions although the polymerizations proceeded via different mechanisms （normal amine mechanism or/and activated monomer mechanism）, which are based on chemical structure of amines. The molecular weights of poly（BLG-co-BLA） copolymers could be mediated by both TEA concentration and polymerization time. Then, debenzylation ofpoly（BLG-co-BLA） copolymers was conducted to prepare the corresponding hydrophilic random eopolymers of poly（LG-co-ASP） with a-subunit structure in ASP structural units. The contents of LG structural units in poly（LG-co-ASP） copolymers matched with those of BLG-NCA in NCA-monomer feeds in ring opening copolymerizations initiated by NHA or TEA and were closed to the theoretical line. The diblock copolymer of poly（BLG-b-BLA） could also be synthesized via living NCA ring opening copolymerization by sequential addition of BLG- NCA and BLA-NCA.
基金the Shahid Chamran University Research Council for partial financial support of this work
文摘For the first time,metal hydrogen sulfates and phosphates/silica gel have been studied as efficient and powerful solid acid catalysts in the ring opening of epoxides with thiocyanate anion.The most significant result was obtained by Al(HSO4)3/SiO2which afforded the corresponding β-hydroxy thiocyanates under mild reaction conditions and in very short reaction times.The cheapness, availability of the catalyst,ease of procedure and work-up make this method attractive for the organic synthesis.
文摘Ligand effect of the catalytic system WCl6-Et2AlCl for ring opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD) was investigated. The experimental results show that adding sterically hindered phenol-2. 6-di-tert-butylcresylol(DTBC) in the catalytic system not only can obviously increase the monomer conversion of polymerization but also improve the mechanical properties, such as notched impact strength (NIS), tensile strength (TS) ect. 5 of the synthesized polyicycolpentadiene (PDCPD). A similar effect can be observed by using a sterically hindered polymeric phenol - linear phenol formaldehyde resin (LPF) as a ligand.
文摘This paper reviewed some recent advances of ring opening metathesis polymerization (ROMP) in tailoring polymers with novel and controlled structures.
文摘A rhodium-catalyzed ring opening reaction of N-Boc-azabenzonorbornadiene with heteroatom nucleophiles was described. Piperidine and piperazine＇s derivatives were nucleophiles in this reaction. The yields of the products 2a-f are good and the regioselectivity are excellent.
文摘The cationic ring-opening polymerization of tetrahydrofiiran using maghnite-H~＋ is reported.Maghnite-H~＋,is a non-toxic solid catalyst issued from proton exchanged montmorillonite clay.Polytetrahydrofuran,also called ＂poly（butandiol） ether＂,with acetate and hydroxyl end groups was successfully synthesized.Effects of reaction temperature, weight ratio of initiator/monomer and reaction time on the conversion of monomer and on the molecular weight are investigated.A cationic mechanism of the reaction was proposed.This chemistry can be considered as a suitable route for preparing poly（THF） as a soft segment for thermoplastic elastomers.
文摘Allylic amines and 1,3-oxazinanes are valuable molecular skeletons in organic synthesis and pharmaceutical industry.A straightforward way to such two types of compounds by solvent-controlled rare-earth metal Lewis acid-catalyzed transformations of 2-(hetero)aryl-N-sulfonylazetidines:the ring-opening isomerization of azetidines to allylic amines and the annulation of azetidines with aldehydes to 1,3-oxazinanes are reported.These two reactions feature scalability,low catalyst loading,mild reaction conditions,excellent yields and regioselectivity with demonstrated utility in three-step product transformations to naftifine,abamine and abamine SG.
文摘A new kind of polyesteramide based on 3-morpholinone and e caprolactone was synthesized by ring opening polymerization with zinc powder as catalyst.The polymer was characterized by^(1)H NMR,GPC and FT-IR.The effect of time,temperature and ratio of m(M)/m(1),n(M)/n(CL)on the reaction was studied.The results show that the optimal reaction temperature is 120℃;the optimal duration of reaction is 24 h;the optimal ratio of m(M)/m(CL)is 50:1;the optimal ratio of n(M)/n(CL)is 1:2.Under the optimal condition the polymer whose M_(n)was 13509 could be obtained while the weight yield was 79%.
基金the Natural Science Foundation of Guangdong Province for financial support （No.04010404）.
文摘We have developed an asymmetric ring opening reaction of oxabenzonorbornadienes with substituted phenolic nucleophiles. Under the reaction conditions （ [Rh（COD）C1]2 （1 mol%）, （S）-（R）-PPF-P^Bu2 （2 mol%）, THF, reflux）, the reaction products were obtained with high yield and enantiomeric excesses （ up to 99% ee）.
文摘We have developed an asymmetric ring opening reaction of azabenzonorbornadiene with substituted piperazine. By increasing the amount of catalyst (from 2.5 to 5%) and ligands (5 to 10%) as well as addition of ammonium iodide, the products can be obtained in high yield and the reaction time shortened dramatically, but the ee values were rather low.
基金supported by the National Natural Science Foundation of China(No20872031)Hubei Provincial Department of Eduction(NoT200701)
文摘An efficient and water tolerant method for the synthesis ofβ-haloamines is described utilizing hydrated nickel（Ⅱ） halides （NiX_2ⅩnH_2O X = Cl,Br,I） and aziridines as starting materials.N-Tosylaziridines reacted with NiCl_2·6H_2O or NiI_2·6H_2O givingβ-chloro -orβ-iodoamines in high yields（73-99%） within a short time,but 10 mol%of n-Bu_4NBr should be added in the reactions of N-tosylaziridines with NiBr_2·3H_2O in order to obtain the high yields of correspondingβ-bromoamines.Solvent played an important role in the reactions.The proper solvent for the reaction of NiCl_2·6H_2O was DMF,while NiBr_2·3H_2O or NiI_2·6H_2O proceeded well in 1,4-dioxane.
文摘A stereoselective and regiospecific synthesis of procursors(2),(4),(6)and(7)of prostacyclin analogues from 2,3-epoxylbicyclo[3.2.0]hept-6-one(1)are described.
基金National Natural Science Foundation of China (Project grant No.: 29874018)
文摘Chloromethyl-2-norbornene was synthesized via Diels-Alder reaction of cyclopentadiene and allyl chloride using a polymer supported boron trifluoride as the catalyst, and was then lithiated and used to initiate a living anionic polymerization of styrene to prepare a macromonome, 5-polystyryl-2-norbornene NBPS. Comb graft copolymer PNBgPS was synthesized via ring opening metathesis polymerization of the macromonomer under the catalysis of ruthenium carbene complex RuCl2(PPh3)2(=CCHtBu) and its polymer supported correspondent. Experimental results showed that the behavior of both the supported boron and supported ruthenium catalysts are superior to their unsupported counterparts. The possible promotion mechanism of the tailor-made supports is discussed.
文摘Visible light photocatalytic redox catalysis has become a powerful tool for organic synthesis, and has opened up new avenues for the formation of challenging structural skeletons and chemical bonds. In this respect, diverse photocatalysts, including ruthenium(II), iridium(Ⅲ), and organic dyes, have been most commonly applied.
