A new and simple route for the synthesis of α,β-unsaturated ketones via cleavage of the C-C(O)C single bond of monoalkylated β-diketone has been described. The reaction was catalyzed by copper, a cheap transition m...A new and simple route for the synthesis of α,β-unsaturated ketones via cleavage of the C-C(O)C single bond of monoalkylated β-diketone has been described. The reaction was catalyzed by copper, a cheap transition metal in a weakly basic medium (K<sub>3</sub>PO<sub>4</sub>) at room temperature. To carry out this study, we first had to synthesize the monoalkylated β-diketones 1. Afterwards, α,β-unsaturated ketones 2 were obtained with high yields around 80%. Finally, all the products were characterized by 1H NMR, 13C NMR, and HRMS spectra. .展开更多
Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that...Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that both cinnamaldehyde and benzalacetone had an evident anticorrosion effect and could reduce the corrosion of steel effectively in acid medium, α,β-unsaturated carbonyl compounds with a benzene ring structure had good adsorption on steel surface. The experiments proved that polymerization of α,β-unsaturated carbonyl compounds on the steel surface at a high temperature and in concentrated acid medium resulted in a good corrosion inhibiting effect, which was attributed to the structures of α,β-unsaturated carbonyl compounds.展开更多
Michael addition of indole and pyrrole to a variety of α, β-unsaturated ketones was efficiently promoted by a catalytic amount of GaCl3 in aqueous media to afford the corresponding products in good to excellent yields.
Microwave irradiation can accelerate the rate of the synthetic reaction of α,β-unsaturated ketones by using KF-Al2O3 as catalyst. The rate enhancement of the reaction is 360-860 fold.
Two new α,β-unsaturated butyrolactone derivatives, 4-(4″-hydroxybenzyl)-3-(3′-hydroxy-phenethyl)furan-2(5H)-one (1) and 3-(3′-hydroxyphenethyl)furan-2(5H)-one (2), together with one known phenolic compound (3), w...Two new α,β-unsaturated butyrolactone derivatives, 4-(4″-hydroxybenzyl)-3-(3′-hydroxy-phenethyl)furan-2(5H)-one (1) and 3-(3′-hydroxyphenethyl)furan-2(5H)-one (2), together with one known phenolic compound (3), were isolated from the tubers of Pleione bulbocodioides (Franch.) Rolfe. Their structures were elucidated by analysis of spectroscopic data.展开更多
Functionalized organozinc reagents can easily under 1, 4-addition reaction withunsaturated esters in the presence of catalytic amount of Ni (acac)_2 and tertiary ammes under verymild conditions to give the products in...Functionalized organozinc reagents can easily under 1, 4-addition reaction withunsaturated esters in the presence of catalytic amount of Ni (acac)_2 and tertiary ammes under verymild conditions to give the products in excellent yields.展开更多
The effect of catalysts P-2 00-Ni(Nickel boride) and P-2 00-Ni-M(M: Co, Fe, Cu, Sn), prepared by adopting a modified recipe, on the chemoselective hydrogenation of carbon carbon double bonds in α,β- unsaturated...The effect of catalysts P-2 00-Ni(Nickel boride) and P-2 00-Ni-M(M: Co, Fe, Cu, Sn), prepared by adopting a modified recipe, on the chemoselective hydrogenation of carbon carbon double bonds in α,β- unsaturated ketones, and the activity of catalysts P-1.80-Ni, P-2 00-Ni or P-1.80(2 00) -Ni-M(M: Pd, Co, Cu) in the selective hydrogenation of carbon carbon double bonds in α,β-unsaturated carboxylic esters, were investigated systematically. According to the experimental results, the selectivities of these catalysts toward the hydrogenation of the carbon carbon double bonds of α,β-unsaturated keones or α,β-unsaturated carboxylic esters are 96%—100% or 100%, respectively.展开更多
Allylsamarium bromide reacts with Q, 6 -unsaturated esters and a -alkyloxy carbonyl α, β-unsaturated esters to give l,2-addition and 1 .4-addition products respectively.
The reaction of α-triazolyl-α, β-unsaturated ketones with phenyl hydrazine was studied. The result indicated that cyclization took place and new heterocyclic compounds of substituted 4,5-2H-pyrazoles were obtained,...The reaction of α-triazolyl-α, β-unsaturated ketones with phenyl hydrazine was studied. The result indicated that cyclization took place and new heterocyclic compounds of substituted 4,5-2H-pyrazoles were obtained, whose structures and conformation were characterized by 1H NMR, IR, MS, elemental analysis and X-ray diffraction.展开更多
Methanol is a safe, economic and easy-to-handle hydrogen source. It has rarely been used in transfer hydrogenation reactions, however. We herein report that a cyclometalated rhodium complex, rhodacycle, catalyzes high...Methanol is a safe, economic and easy-to-handle hydrogen source. It has rarely been used in transfer hydrogenation reactions, however. We herein report that a cyclometalated rhodium complex, rhodacycle, catalyzes highly chemoselective hydrogenation of α,β-unsaturated ketones with methanol as the hydrogen source. A wide variety of chalcones, styryl methyl ketones and vinyl methyl ketones, including sterically demanding ones, were reduced to the saturated ketones in refluxing methanol in a short reaction time, with no need for inter gas protection, and no reduction of the carbonyl moieties was observed. The catalysis described provides a practically easy and operationally safe method for the reduction of olefinic bonds in α,β-unsaturated ketone compounds.展开更多
N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted additio...N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted addition mechanism was provided to explain the difference.展开更多
Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α, β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were ef...Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α, β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were efficient media for Doebner condensation, which could be recycled easily. The highest yields could reach 93% and 90% in [Bmim]BF4 and [Bpy]BF4, respectively.展开更多
Functionalized organozinc reagents can easily conduct 1,4-addition reaction with unsaturated esters in the presence of Cu(OAc)2 and LiCl under very Anld conditions to give the products in excellent yields.
An efficient enantioselective Michael addition of ethyl-2-cyanoacetate and diethyl malonate to α,β-unsaturated ketones catalyzed by a simple chiral Schiff base, and products were obtained in good yields at room temp...An efficient enantioselective Michael addition of ethyl-2-cyanoacetate and diethyl malonate to α,β-unsaturated ketones catalyzed by a simple chiral Schiff base, and products were obtained in good yields at room temperature.展开更多
Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free co...Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free conditions. The reactants were ground in a mortar with a pestle for about 30 minutes. The aromatic acids underwent nitro decarboxylation and afforded β-nitro styrene derivatives in very good yield while α, β-unsaturated aliphatic carboxylic acids gave corresponding nitro derivatives. Addition of PEG accelerated rate of the reaction enormously. Reaction times substantially decreased from several hours to few minutes followed by highly significant increase in the product yield. Among the several PEGs PEG-300 has been found to be much more effective than other PEGs.展开更多
Regio and stereoselective synthesis of substituted dihydrofurans were accomplished by eeric ammonium nitrate mediated oxidative cycloaddition of 1,3-dicarbonyls to β-aryl-α,β-unsaturated ketones in moderate yields.
A new synthetic method is described here to obtain α, β-unsaturated ketones through alkenes through a sequence involving f (1) cycloaddition of alkenes with dichloroketene, (2) dechlorination of adducts, (3)acidprom...A new synthetic method is described here to obtain α, β-unsaturated ketones through alkenes through a sequence involving f (1) cycloaddition of alkenes with dichloroketene, (2) dechlorination of adducts, (3)acidpromoted ring-opening isomerization ofcyclobutanones in CF3 CO2H.展开更多
Promoted by SmI3 β -diketones， β-ketoesters and α -cyano esters were added to α,β -unsaturated esters to form δ-carbonyl esters in mild conditions in moderate to good yields.
Catalyzed by ytterbium（III） triflate hydrate [Yb（OTf）3.xH20], the Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran der...Catalyzed by ytterbium（III） triflate hydrate [Yb（OTf）3.xH20], the Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran derivatives, respectively were studied.展开更多
Air-stable cationic organobismuth complexes (2-5) possessing both acidic and basic characters were synthesized. The catalyst system that comprises an air-stable bifunctional Lewis acidic/basic organobismuth complex an...Air-stable cationic organobismuth complexes (2-5) possessing both acidic and basic characters were synthesized. The catalyst system that comprises an air-stable bifunctional Lewis acidic/basic organobismuth complex and [Bmim]BF4 showed high catalytic activity, diastereoselec-tivity, stability, and reusability in the one-pot synthesis of (E)-α,β-unsaturat-ed ketones through highly selective crossed-condensation of ketones and aldehydes. Through switching the reaction from homogeneous to heterogeneous, the system shows facile separation ability and facile reusability.展开更多
文摘A new and simple route for the synthesis of α,β-unsaturated ketones via cleavage of the C-C(O)C single bond of monoalkylated β-diketone has been described. The reaction was catalyzed by copper, a cheap transition metal in a weakly basic medium (K<sub>3</sub>PO<sub>4</sub>) at room temperature. To carry out this study, we first had to synthesize the monoalkylated β-diketones 1. Afterwards, α,β-unsaturated ketones 2 were obtained with high yields around 80%. Finally, all the products were characterized by 1H NMR, 13C NMR, and HRMS spectra. .
文摘Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that both cinnamaldehyde and benzalacetone had an evident anticorrosion effect and could reduce the corrosion of steel effectively in acid medium, α,β-unsaturated carbonyl compounds with a benzene ring structure had good adsorption on steel surface. The experiments proved that polymerization of α,β-unsaturated carbonyl compounds on the steel surface at a high temperature and in concentrated acid medium resulted in a good corrosion inhibiting effect, which was attributed to the structures of α,β-unsaturated carbonyl compounds.
基金support by the Natural Science Foundation of Zhejiang Province(No.Y4051137,Y405015 and Y4080177)
文摘Michael addition of indole and pyrrole to a variety of α, β-unsaturated ketones was efficiently promoted by a catalytic amount of GaCl3 in aqueous media to afford the corresponding products in good to excellent yields.
文摘Microwave irradiation can accelerate the rate of the synthetic reaction of α,β-unsaturated ketones by using KF-Al2O3 as catalyst. The rate enhancement of the reaction is 360-860 fold.
文摘Two new α,β-unsaturated butyrolactone derivatives, 4-(4″-hydroxybenzyl)-3-(3′-hydroxy-phenethyl)furan-2(5H)-one (1) and 3-(3′-hydroxyphenethyl)furan-2(5H)-one (2), together with one known phenolic compound (3), were isolated from the tubers of Pleione bulbocodioides (Franch.) Rolfe. Their structures were elucidated by analysis of spectroscopic data.
文摘Functionalized organozinc reagents can easily under 1, 4-addition reaction withunsaturated esters in the presence of catalytic amount of Ni (acac)_2 and tertiary ammes under verymild conditions to give the products in excellent yields.
文摘The effect of catalysts P-2 00-Ni(Nickel boride) and P-2 00-Ni-M(M: Co, Fe, Cu, Sn), prepared by adopting a modified recipe, on the chemoselective hydrogenation of carbon carbon double bonds in α,β- unsaturated ketones, and the activity of catalysts P-1.80-Ni, P-2 00-Ni or P-1.80(2 00) -Ni-M(M: Pd, Co, Cu) in the selective hydrogenation of carbon carbon double bonds in α,β-unsaturated carboxylic esters, were investigated systematically. According to the experimental results, the selectivities of these catalysts toward the hydrogenation of the carbon carbon double bonds of α,β-unsaturated keones or α,β-unsaturated carboxylic esters are 96%—100% or 100%, respectively.
文摘Allylsamarium bromide reacts with Q, 6 -unsaturated esters and a -alkyloxy carbonyl α, β-unsaturated esters to give l,2-addition and 1 .4-addition products respectively.
文摘The reaction of α-triazolyl-α, β-unsaturated ketones with phenyl hydrazine was studied. The result indicated that cyclization took place and new heterocyclic compounds of substituted 4,5-2H-pyrazoles were obtained, whose structures and conformation were characterized by 1H NMR, IR, MS, elemental analysis and X-ray diffraction.
基金the Higher Committee for Education Development in Iraq for financial support(AHB)the Commonwealth Scholarships Commission in the UK for a Split-Site PhD Scholarship(RB)
文摘Methanol is a safe, economic and easy-to-handle hydrogen source. It has rarely been used in transfer hydrogenation reactions, however. We herein report that a cyclometalated rhodium complex, rhodacycle, catalyzes highly chemoselective hydrogenation of α,β-unsaturated ketones with methanol as the hydrogen source. A wide variety of chalcones, styryl methyl ketones and vinyl methyl ketones, including sterically demanding ones, were reduced to the saturated ketones in refluxing methanol in a short reaction time, with no need for inter gas protection, and no reduction of the carbonyl moieties was observed. The catalysis described provides a practically easy and operationally safe method for the reduction of olefinic bonds in α,β-unsaturated ketone compounds.
文摘N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted addition mechanism was provided to explain the difference.
基金supported by National 863 High-Tech Research and Development Program of China(No.2007AA05Z101).
文摘Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α, β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were efficient media for Doebner condensation, which could be recycled easily. The highest yields could reach 93% and 90% in [Bmim]BF4 and [Bpy]BF4, respectively.
文摘Functionalized organozinc reagents can easily conduct 1,4-addition reaction with unsaturated esters in the presence of Cu(OAc)2 and LiCl under very Anld conditions to give the products in excellent yields.
基金We appreciate the National Natural Science Foundation of China （No. 20962018, 20862015, 20762009 and 20562011） for supporting this research.
文摘An efficient enantioselective Michael addition of ethyl-2-cyanoacetate and diethyl malonate to α,β-unsaturated ketones catalyzed by a simple chiral Schiff base, and products were obtained in good yields at room temperature.
文摘Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free conditions. The reactants were ground in a mortar with a pestle for about 30 minutes. The aromatic acids underwent nitro decarboxylation and afforded β-nitro styrene derivatives in very good yield while α, β-unsaturated aliphatic carboxylic acids gave corresponding nitro derivatives. Addition of PEG accelerated rate of the reaction enormously. Reaction times substantially decreased from several hours to few minutes followed by highly significant increase in the product yield. Among the several PEGs PEG-300 has been found to be much more effective than other PEGs.
文摘Regio and stereoselective synthesis of substituted dihydrofurans were accomplished by eeric ammonium nitrate mediated oxidative cycloaddition of 1,3-dicarbonyls to β-aryl-α,β-unsaturated ketones in moderate yields.
文摘A new synthetic method is described here to obtain α, β-unsaturated ketones through alkenes through a sequence involving f (1) cycloaddition of alkenes with dichloroketene, (2) dechlorination of adducts, (3)acidpromoted ring-opening isomerization ofcyclobutanones in CF3 CO2H.
文摘Promoted by SmI3 β -diketones， β-ketoesters and α -cyano esters were added to α,β -unsaturated esters to form δ-carbonyl esters in mild conditions in moderate to good yields.
基金the National Natural Science Foundation of China (No.20676123) for financial support.
文摘Catalyzed by ytterbium（III） triflate hydrate [Yb（OTf）3.xH20], the Michael addition and cyclocondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran derivatives, respectively were studied.
文摘Air-stable cationic organobismuth complexes (2-5) possessing both acidic and basic characters were synthesized. The catalyst system that comprises an air-stable bifunctional Lewis acidic/basic organobismuth complex and [Bmim]BF4 showed high catalytic activity, diastereoselec-tivity, stability, and reusability in the one-pot synthesis of (E)-α,β-unsaturat-ed ketones through highly selective crossed-condensation of ketones and aldehydes. Through switching the reaction from homogeneous to heterogeneous, the system shows facile separation ability and facile reusability.
