The enantioselective double Michael reaction of N-Boc-3-nonsubstitued oxindoles with dienones catalyzed by chiral monoimide protected cyclohexane-1,2-diamines was developed. A wide range of optically active spirocycli...The enantioselective double Michael reaction of N-Boc-3-nonsubstitued oxindoles with dienones catalyzed by chiral monoimide protected cyclohexane-1,2-diamines was developed. A wide range of optically active spirocyclic oxindoles were obtained up to 98% yield and up to 89% ee.展开更多
The manufacture of 1,1-dichloroethylene（1,1-DCE） usually employs liquid phase method to perform the dehydrochlorination of 1,1,2-trichloroethane（TCE）, where large amounts of high-concentration salty wastewater is ...The manufacture of 1,1-dichloroethylene（1,1-DCE） usually employs liquid phase method to perform the dehydrochlorination of 1,1,2-trichloroethane（TCE）, where large amounts of high-concentration salty wastewater is produced inevitably. It has been a long-term goal to achieve the gas phase synthesis of 1,1-DCE via supported cata- lysts. In this work, the gas-phase synthesis of 1,1-DCE from TCE was studied in the presence of pentaethylenehexamine（PEHA） supported on silica. High and stable selectivity to 1,1-DCE（up to 98%） was obtained, which could be ascribed to the relatively strong basicity of PEHA according to a proposed E2 mechanism. The formation of PEHA chloride from the HCI generated in situ was detected and was considered to be the main reason for the deactivation of PEHA catalyst.展开更多
Graphene is of great interest because of its exciting properties and potential applications,but its production on a large-scale still presents considerable challenges.Herein,we report the synthesis of predominately fe...Graphene is of great interest because of its exciting properties and potential applications,but its production on a large-scale still presents considerable challenges.Herein,we report the synthesis of predominately few-layer graphene,due toπ–πstacking,and single-layer graphene from reaction between hexabromobenzene and Na metal,followed by annealing to improve crystallinity.The reaction proceeds via a free-radical C(sp^(2))–C(sp^(2))coupling mechanism,which is supported by theoretical calculations.The graphene can host unpaired spin electrons,leading to a short acquisition time for a solidstate nuclear magnetic resonance 13C spectrum from unlabeled graphene,which is ascribed to the very short spin-lattice relaxation time.High catalytic activity for transforming amine to imine with a conversion of>99%and a yield of∼97%is demonstrated,and high electronic conductivity of∼105 S·m^(−1) is found by terahertz spectroscopy.The reaction delivers a method for synthesizing graphene with a high spin concentration from perbrominated benzene molecules by using an active metallic agent,such as Na,Li,or Mg.展开更多
An efficient phase-transfer-catalyzed directed reductive amination of α-keto esters was described using simple substituted benzyl amines as nitrogen source and K2CO3 as base at room temperature, giving a series of al...An efficient phase-transfer-catalyzed directed reductive amination of α-keto esters was described using simple substituted benzyl amines as nitrogen source and K2CO3 as base at room temperature, giving a series of aliphatic a-amino acid derivatives in moderate to high yields（up to 99%）. Preliminary study on this asymmetric process showed that cinchona-derived phase transfer catalyst was elTective, aflbrding the corresponding product in 13% e.e. and 40% yield.展开更多
文摘The enantioselective double Michael reaction of N-Boc-3-nonsubstitued oxindoles with dienones catalyzed by chiral monoimide protected cyclohexane-1,2-diamines was developed. A wide range of optically active spirocyclic oxindoles were obtained up to 98% yield and up to 89% ee.
基金Supported by the National Natural Science Foundation of China（No.NSFC-21476207）, and the Open Research Fund of Top Key Discipline of Chemistry in Zhej iang Provincial Colleges（Zhej iang Normal University）, China（No.ZJHX201413 ）.
文摘The manufacture of 1,1-dichloroethylene（1,1-DCE） usually employs liquid phase method to perform the dehydrochlorination of 1,1,2-trichloroethane（TCE）, where large amounts of high-concentration salty wastewater is produced inevitably. It has been a long-term goal to achieve the gas phase synthesis of 1,1-DCE via supported cata- lysts. In this work, the gas-phase synthesis of 1,1-DCE from TCE was studied in the presence of pentaethylenehexamine（PEHA） supported on silica. High and stable selectivity to 1,1-DCE（up to 98%） was obtained, which could be ascribed to the relatively strong basicity of PEHA according to a proposed E2 mechanism. The formation of PEHA chloride from the HCI generated in situ was detected and was considered to be the main reason for the deactivation of PEHA catalyst.
基金This work was financially support from the National Key R&D Program of China(no.2016YFA0200200)the National Program on Key Basic Research Project(973 program,no.2013CB933804)+1 种基金the National Natural Science Foundation of China(no.21271112)the Tribology Science Fund of State Key Laboratory of Tribology(SKLTKF20B18).
文摘Graphene is of great interest because of its exciting properties and potential applications,but its production on a large-scale still presents considerable challenges.Herein,we report the synthesis of predominately few-layer graphene,due toπ–πstacking,and single-layer graphene from reaction between hexabromobenzene and Na metal,followed by annealing to improve crystallinity.The reaction proceeds via a free-radical C(sp^(2))–C(sp^(2))coupling mechanism,which is supported by theoretical calculations.The graphene can host unpaired spin electrons,leading to a short acquisition time for a solidstate nuclear magnetic resonance 13C spectrum from unlabeled graphene,which is ascribed to the very short spin-lattice relaxation time.High catalytic activity for transforming amine to imine with a conversion of>99%and a yield of∼97%is demonstrated,and high electronic conductivity of∼105 S·m^(−1) is found by terahertz spectroscopy.The reaction delivers a method for synthesizing graphene with a high spin concentration from perbrominated benzene molecules by using an active metallic agent,such as Na,Li,or Mg.
基金Supported by the Natural Science Foundation of China（No.21402127）. Foundation of Liaoning Province Education Department（No.l,2013381）, PhD Research Startup Foundation of Liaoning Province（No.20131110）, and Career Dcvclopment Support Plan for Young and Middle-aged Teachers in Shenyang Pharmaceutical University.
文摘An efficient phase-transfer-catalyzed directed reductive amination of α-keto esters was described using simple substituted benzyl amines as nitrogen source and K2CO3 as base at room temperature, giving a series of aliphatic a-amino acid derivatives in moderate to high yields（up to 99%）. Preliminary study on this asymmetric process showed that cinchona-derived phase transfer catalyst was elTective, aflbrding the corresponding product in 13% e.e. and 40% yield.
