Wereport a base-promoted catalyst-free protocol for the highly regioselective hydroacylation of styrenes with hydrazones derived from naturally abundant aldehydes.This protocolgeneratedlinearketoneswith goodfunctional...Wereport a base-promoted catalyst-free protocol for the highly regioselective hydroacylation of styrenes with hydrazones derived from naturally abundant aldehydes.This protocolgeneratedlinearketoneswith goodfunctional grouptolerance anda broadsubstrate scope under mild conditions.Mechanistic studies showed that the addition of hydrazone anion to a styrene double bond was the key step,different from previoushydroacylationpathways(viaorganometallic complexes or radical intermediates).展开更多
Regioselective addition reactions of silyl enolates to a, b-unsaturated aldehyde and its acetal catalyzed by MgI2 etherate give aldol adducts (1, 2-addition) preferentially over Michael adducts (1, 4-addition). This ...Regioselective addition reactions of silyl enolates to a, b-unsaturated aldehyde and its acetal catalyzed by MgI2 etherate give aldol adducts (1, 2-addition) preferentially over Michael adducts (1, 4-addition). This unique regioselectivity is distinctly different with other Lewis acidic promoters and may be attributed to the high oxyphilicity of IMg+.展开更多
In the presence of catalytic amount of cesium hydroxide, the hydrothiolation of alkynyl sulfides occurred at room temperature in DMF under nitrogen atmosphere to afford exclusive （Z）-1,2-diorganothio-1-alkene in exc...In the presence of catalytic amount of cesium hydroxide, the hydrothiolation of alkynyl sulfides occurred at room temperature in DMF under nitrogen atmosphere to afford exclusive （Z）-1,2-diorganothio-1-alkene in excellent yields. It could provide a new and expedient way for the preparation of symmetrical and unsymmetrical （Z）-1,2-diorganolthiol-1-alkenes.展开更多
By the cyclization of 4,4-dimethylcyclohexane-1,3-dione with different aromatic aldehydes, the xanthene regio- isomers were obtained. The diversity of xanthene isomers could be determined. The electronic and steric ef...By the cyclization of 4,4-dimethylcyclohexane-1,3-dione with different aromatic aldehydes, the xanthene regio- isomers were obtained. The diversity of xanthene isomers could be determined. The electronic and steric effects on aromatic aldehydes could be observed.展开更多
The copper-catalyzed,highly enantioselective 1,4-protoboration of terminal 1,3-dienes with proton source and B2Pin2 has been developed.Chiral allylic boronate reagents,which are significant precursors for many well-es...The copper-catalyzed,highly enantioselective 1,4-protoboration of terminal 1,3-dienes with proton source and B2Pin2 has been developed.Chiral allylic boronate reagents,which are significant precursors for many well-established transformations,were prepared by this novel method with good functional group tolerance and enantioselectivity.Further studies indicated the products could be used as versatile precursors for asymmetric transformations and natural products syntheses.The mechanism of this reaction was investigated by control and reaction monitoring experiments.展开更多
Most of the electrophilic additions on carbon-carbon multiply bond can be summarized as: where Y are certain atoms on the fight of the periodic table; Z may be null, atom or group. Regardless of the rate law of Ad_E2 ...Most of the electrophilic additions on carbon-carbon multiply bond can be summarized as: where Y are certain atoms on the fight of the periodic table; Z may be null, atom or group. Regardless of the rate law of Ad_E2 Ad_E3 or the more complex kinetics, the micromechanisms of transition state of electrophilic addition can be divided into two sorts, i.e. open ion and bridged ion mechanisms. The former one allows free rotation of展开更多
1 Results We have already published a double nucleophilic addition reaction of α,β-unsaturated imines with several nucleophiles such as ketene silyl acetals, trimethylsilyl cyanides, trimethylsilyl azides and thiols...1 Results We have already published a double nucleophilic addition reaction of α,β-unsaturated imines with several nucleophiles such as ketene silyl acetals, trimethylsilyl cyanides, trimethylsilyl azides and thiols[1]. However, it was not easy to use N-allylideneamine 2 derived from acrolein for such reactions. Since there is no substituent at the β-position, imine 2 has high reactivity and are prone to be polymerization. We report the first synthesis of N-allylideneamines 2 using the isomerization of ...展开更多
基金Project supported by the National Natural Science Foundation of Chinathe Foundation of National Key Laboratory of Bioorganic Natural Product Chemistry of China.
文摘Linalyl alkyl or aryl carbinols were regioselectively synthesized by the reaction of geranyl bromide and powdered tin with aldehydes and ketones.
基金from the National Natural Science Foundation of China(grant no.21971093)the International Joint Research Centre for Green Catalysis and Synthesis(grant no.2016B01017),and the 111 project.
文摘Wereport a base-promoted catalyst-free protocol for the highly regioselective hydroacylation of styrenes with hydrazones derived from naturally abundant aldehydes.This protocolgeneratedlinearketoneswith goodfunctional grouptolerance anda broadsubstrate scope under mild conditions.Mechanistic studies showed that the addition of hydrazone anion to a styrene double bond was the key step,different from previoushydroacylationpathways(viaorganometallic complexes or radical intermediates).
基金We are grateful for the financial supports from the National Outstanding Youth Fund No.29925204)the Foundation for University Key Teacher by the Ministry of Education of Chinaa Visiting Fund of the National Laboratory of Applied Organic Chemistry.
文摘Regioselective addition reactions of silyl enolates to a, b-unsaturated aldehyde and its acetal catalyzed by MgI2 etherate give aldol adducts (1, 2-addition) preferentially over Michael adducts (1, 4-addition). This unique regioselectivity is distinctly different with other Lewis acidic promoters and may be attributed to the high oxyphilicity of IMg+.
基金Project supported by the National Natural Science Foundation of China （Nos. 21071152, 20372020）.
文摘In the presence of catalytic amount of cesium hydroxide, the hydrothiolation of alkynyl sulfides occurred at room temperature in DMF under nitrogen atmosphere to afford exclusive （Z）-1,2-diorganothio-1-alkene in excellent yields. It could provide a new and expedient way for the preparation of symmetrical and unsymmetrical （Z）-1,2-diorganolthiol-1-alkenes.
文摘By the cyclization of 4,4-dimethylcyclohexane-1,3-dione with different aromatic aldehydes, the xanthene regio- isomers were obtained. The diversity of xanthene isomers could be determined. The electronic and steric effects on aromatic aldehydes could be observed.
基金a generous grant from Tianjin University,National Natural Science Foundation of China(no.21801181).
文摘The copper-catalyzed,highly enantioselective 1,4-protoboration of terminal 1,3-dienes with proton source and B2Pin2 has been developed.Chiral allylic boronate reagents,which are significant precursors for many well-established transformations,were prepared by this novel method with good functional group tolerance and enantioselectivity.Further studies indicated the products could be used as versatile precursors for asymmetric transformations and natural products syntheses.The mechanism of this reaction was investigated by control and reaction monitoring experiments.
基金Project supported by the National Natural Science Foundation of China.
文摘Most of the electrophilic additions on carbon-carbon multiply bond can be summarized as: where Y are certain atoms on the fight of the periodic table; Z may be null, atom or group. Regardless of the rate law of Ad_E2 Ad_E3 or the more complex kinetics, the micromechanisms of transition state of electrophilic addition can be divided into two sorts, i.e. open ion and bridged ion mechanisms. The former one allows free rotation of
文摘1 Results We have already published a double nucleophilic addition reaction of α,β-unsaturated imines with several nucleophiles such as ketene silyl acetals, trimethylsilyl cyanides, trimethylsilyl azides and thiols[1]. However, it was not easy to use N-allylideneamine 2 derived from acrolein for such reactions. Since there is no substituent at the β-position, imine 2 has high reactivity and are prone to be polymerization. We report the first synthesis of N-allylideneamines 2 using the isomerization of ...
