Using 2-[bis（alkylthio）methylene]-3-oxo-N-o-tolylbutanamides 1 as odorless thiol equivalents, an efficient and odorless synthesis of thioethers has been developed. Promoted by NaOH in EtOH, the cleavage of 1 commenc...Using 2-[bis（alkylthio）methylene]-3-oxo-N-o-tolylbutanamides 1 as odorless thiol equivalents, an efficient and odorless synthesis of thioethers has been developed. Promoted by NaOH in EtOH, the cleavage of 1 commences to generate thiolate anions, and the generated thiolate anions then react with halides to give various thioethers in good yield. It is noteworthy that only a very faint odor ofthiols can be perceived during both the reaction and the workup.展开更多
The title compounds 3 and 4 condensed with aromatic aldehydes to give a--aroylsicinnamoyl ketene cyclic dithioacetals 5 and 6 with sodium ethoxide as the base. The stereochemistryofs and 6 was assigned as E-configurat...The title compounds 3 and 4 condensed with aromatic aldehydes to give a--aroylsicinnamoyl ketene cyclic dithioacetals 5 and 6 with sodium ethoxide as the base. The stereochemistryofs and 6 was assigned as E-configuration by 1H NMR.展开更多
A simple and efficient protocol for the deprotection of dithioacetal,1,3-dithianes and 1,3-dithiolanes has been developed using H_2O_2-SOC1_2 reagent system.In addition to the absence of overoxidation products for oxi...A simple and efficient protocol for the deprotection of dithioacetal,1,3-dithianes and 1,3-dithiolanes has been developed using H_2O_2-SOC1_2 reagent system.In addition to the absence of overoxidation products for oxidation-prone substrates,high chemoselectivity, the low cost and availability of the reagents,simplicity of the method,short reaction times,and excellent yields can also be considered as strong points for this method.展开更多
α-Oxoketene dithioacetals 2 via, 1,2-nucleophilic addition by allyl magnesium bromide afforded corresponding alcohols (3).Treated with water and catalyzed by Lewis acid, the alcohols 3 were converted regiospecifical... α-Oxoketene dithioacetals 2 via, 1,2-nucleophilic addition by allyl magnesium bromide afforded corresponding alcohols (3).Treated with water and catalyzed by Lewis acid, the alcohols 3 were converted regiospecifically to the conjugated 1,1—dialkylthio—1,3,5 hexatrienes (4). Both the alcohol 8 and its methoxy methyl ether 9 were sensative to dilute sulfuric acid and cyclized under this condition to form the aryl methylthio ether (10).展开更多
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
Chloroalkanes are important building blocks in the synthesis,but their use in redox chemistry is limited by their negative reduction potentials.Electrosynthesis can precisely control the reaction energy just by adjust...Chloroalkanes are important building blocks in the synthesis,but their use in redox chemistry is limited by their negative reduction potentials.Electrosynthesis can precisely control the reaction energy just by adjusting the current or voltage to achieve the selectivity of regulation.In this study,the consecutively paired electrolyticmediated controllable radical cross-coupling of thiophenols with dichloromethane was developed to deliver the dithioacetals,sulfides,and sulfoxides in the absence of electrochemical mediator conditions.It features broad substrate scope,simple operation,gram-scale synthesis,and is eco-friendly.Mechanistic studies reveal that this electrochemical reaction is radical-induced cross-coupling of thiophenols with dichloromethane.展开更多
Bromo ketene dithioacetals (5) were prepared in high yields by reaction of α,α-diacetyl ketene dithioacetals (4) with bromine catalyzed by FeBr 3 at room temperature. This new reaction is proposed involving an ipso ...Bromo ketene dithioacetals (5) were prepared in high yields by reaction of α,α-diacetyl ketene dithioacetals (4) with bromine catalyzed by FeBr 3 at room temperature. This new reaction is proposed involving an ipso electrophilic addition-deacetylation mechanism.展开更多
The α-acetyl ketene dithioacetals 2, which bear various alkylthio groups, are a kind of important intermediates in organic synthesis. In this paper, dithioacetals 2 were prepared in very high yields (90%—100%) via t...The α-acetyl ketene dithioacetals 2, which bear various alkylthio groups, are a kind of important intermediates in organic synthesis. In this paper, dithioacetals 2 were prepared in very high yields (90%—100%) via the deacetylation reaction of the corresponding α,α-diacetyl ketene dithioacetals 1 in the presence of concentrated sulfuric acid. This reaction involves an %in-situ% electrophilic addition-deacetylation mechanism and shows the nucleophilicity of the α-carbon atom in α-oxo ketenedithioacetals. Meanwhile, when the reaction time was prolonged to 22—25 h, the β-keto thiolesters 3a and 3c were produced in good yields.展开更多
基金This work was supported by the National Natural Science Foundation of China （No. 20572013） and the Doctoral Foundation of Anshan Normal University.
文摘Using 2-[bis（alkylthio）methylene]-3-oxo-N-o-tolylbutanamides 1 as odorless thiol equivalents, an efficient and odorless synthesis of thioethers has been developed. Promoted by NaOH in EtOH, the cleavage of 1 commences to generate thiolate anions, and the generated thiolate anions then react with halides to give various thioethers in good yield. It is noteworthy that only a very faint odor ofthiols can be perceived during both the reaction and the workup.
文摘The title compounds 3 and 4 condensed with aromatic aldehydes to give a--aroylsicinnamoyl ketene cyclic dithioacetals 5 and 6 with sodium ethoxide as the base. The stereochemistryofs and 6 was assigned as E-configuration by 1H NMR.
基金the Razi University Research Council for partial support of this work
文摘A simple and efficient protocol for the deprotection of dithioacetal,1,3-dithianes and 1,3-dithiolanes has been developed using H_2O_2-SOC1_2 reagent system.In addition to the absence of overoxidation products for oxidation-prone substrates,high chemoselectivity, the low cost and availability of the reagents,simplicity of the method,short reaction times,and excellent yields can also be considered as strong points for this method.
文摘 α-Oxoketene dithioacetals 2 via, 1,2-nucleophilic addition by allyl magnesium bromide afforded corresponding alcohols (3).Treated with water and catalyzed by Lewis acid, the alcohols 3 were converted regiospecifically to the conjugated 1,1—dialkylthio—1,3,5 hexatrienes (4). Both the alcohol 8 and its methoxy methyl ether 9 were sensative to dilute sulfuric acid and cyclized under this condition to form the aryl methylthio ether (10).
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This work is supported by the National Natural Science Foundation of China(No.21902083)the Natural Science Foundation of Shandong Province(No.ZR2020QB130)This work is also supported by the Talent Program Foundation of Qufu Normal University(Nos.6132 and 6125).
文摘Chloroalkanes are important building blocks in the synthesis,but their use in redox chemistry is limited by their negative reduction potentials.Electrosynthesis can precisely control the reaction energy just by adjusting the current or voltage to achieve the selectivity of regulation.In this study,the consecutively paired electrolyticmediated controllable radical cross-coupling of thiophenols with dichloromethane was developed to deliver the dithioacetals,sulfides,and sulfoxides in the absence of electrochemical mediator conditions.It features broad substrate scope,simple operation,gram-scale synthesis,and is eco-friendly.Mechanistic studies reveal that this electrochemical reaction is radical-induced cross-coupling of thiophenols with dichloromethane.
文摘Bromo ketene dithioacetals (5) were prepared in high yields by reaction of α,α-diacetyl ketene dithioacetals (4) with bromine catalyzed by FeBr 3 at room temperature. This new reaction is proposed involving an ipso electrophilic addition-deacetylation mechanism.
文摘The α-acetyl ketene dithioacetals 2, which bear various alkylthio groups, are a kind of important intermediates in organic synthesis. In this paper, dithioacetals 2 were prepared in very high yields (90%—100%) via the deacetylation reaction of the corresponding α,α-diacetyl ketene dithioacetals 1 in the presence of concentrated sulfuric acid. This reaction involves an %in-situ% electrophilic addition-deacetylation mechanism and shows the nucleophilicity of the α-carbon atom in α-oxo ketenedithioacetals. Meanwhile, when the reaction time was prolonged to 22—25 h, the β-keto thiolesters 3a and 3c were produced in good yields.
