Over the past decade many bifunctional amine-thioureas have been developed as active metal-free organocatalysts. Coopera-tive catalysis of these amino-thioureas allows high reaction rates and excellent transfer of ste...Over the past decade many bifunctional amine-thioureas have been developed as active metal-free organocatalysts. Coopera-tive catalysis of these amino-thioureas allows high reaction rates and excellent transfer of stereocbemical information. Despite these impressive advances, the design of new high-performance catalysts for applications in asymmetric catalytic reactions is of ongoing interest in organic chemistry. Herein we describe a cooperative catalyst system consisting of a chiral amine thiourea and an achiral organic acid that promotes the conjugate addition of 4-nonsubstituted pyrazolones to nitroolefins and subsequent dearomative chlorination. The corresponding adducts and the subsequent products were obtained in high to excel lent yields （up to 99%） and high stereoselectivities （up to 99/1 dr, 98% ee） under mild reacton conditions. These transforma tions provide an easy access to enantio-enriched pvrazole derivatives, which could possess Potential oharmaceutical activity.展开更多
An organocatalytic asymmetric branching sequence was realized in the presence of 10 mol%of(DHQD)2AQN,affording the sequential products with three stereocentres,including two quaternary carbon centres,in 47%-79%yields ...An organocatalytic asymmetric branching sequence was realized in the presence of 10 mol%of(DHQD)2AQN,affording the sequential products with three stereocentres,including two quaternary carbon centres,in 47%-79%yields with 85%-99%ee.展开更多
The direct asymmetric three-component reaction of an aromatic (or cinnamic) aldehyde, an amine and a phosphite was investigated by employing chiral BrΦnsted acid. In general, modest to good enantioselectivities (31%...The direct asymmetric three-component reaction of an aromatic (or cinnamic) aldehyde, an amine and a phosphite was investigated by employing chiral BrΦnsted acid. In general, modest to good enantioselectivities (31%–87% ee) could be obtained in acceptable isolated yields (61%–91%) for a series of substrates.展开更多
基金supported by the National Natural Science Foundation of China(21172170 and 21225208)the National Basic Research Program of China(973 Program,2014CB745100)
文摘Over the past decade many bifunctional amine-thioureas have been developed as active metal-free organocatalysts. Coopera-tive catalysis of these amino-thioureas allows high reaction rates and excellent transfer of stereocbemical information. Despite these impressive advances, the design of new high-performance catalysts for applications in asymmetric catalytic reactions is of ongoing interest in organic chemistry. Herein we describe a cooperative catalyst system consisting of a chiral amine thiourea and an achiral organic acid that promotes the conjugate addition of 4-nonsubstituted pyrazolones to nitroolefins and subsequent dearomative chlorination. The corresponding adducts and the subsequent products were obtained in high to excel lent yields （up to 99%） and high stereoselectivities （up to 99/1 dr, 98% ee） under mild reacton conditions. These transforma tions provide an easy access to enantio-enriched pvrazole derivatives, which could possess Potential oharmaceutical activity.
基金supported financially by the National Natural Science Foundation of China(Nos.20972110 and 20902067).
文摘An organocatalytic asymmetric branching sequence was realized in the presence of 10 mol%of(DHQD)2AQN,affording the sequential products with three stereocentres,including two quaternary carbon centres,in 47%-79%yields with 85%-99%ee.
基金supported by the National Natural Science Foundation of China (20772091)Tianjin Municipal Science and Technology Commis-sion (07JCZDJC04700)
文摘The direct asymmetric three-component reaction of an aromatic (or cinnamic) aldehyde, an amine and a phosphite was investigated by employing chiral BrΦnsted acid. In general, modest to good enantioselectivities (31%–87% ee) could be obtained in acceptable isolated yields (61%–91%) for a series of substrates.
