The Experts below are selected from a list of 2727 Experts worldwide ranked by ideXlab platform
Tian-li Wang - One of the best experts on this subject based on the ideXlab platform.
-
Enantiodivergent Kinetic Resolution of 1,1'-Biaryl-2,2'-Diols and Amino Alcohols by Dipeptide-Phosphonium Salt Catalysis Inspired by the Atherton-Todd Reaction.
Angewandte Chemie (International ed. in English), 2021Co-Authors: Siqiang Fang, Jianke Pan, Xiaoyu Ren, Jian-ping Tan, Yuan Chen, Hongkui Zhang, Tian-li WangAbstract:Herein, we disclose a highly enantiodivergent organocatalytic protocol towards the synthesis of atropisomeric biaryls, through a kinetic resolution inspired by dipeptide-Phosphonium Salt-catalyzed Atherton-Todd (A-T) reaction. This flexible approach led to both R- and S-enantiomers by fine-tuning of bifunctional Phosphonium with excellent selectivity factors (s) of up to 1057 and 525, respectively. The potential of newly synthesized O-phosphorylated biaryl diols was illustrated by providing a platform for the synthesis of axially chiral organophosphorus compounds. Mechanistic investigations suggest that the bifunctional Phosphonium halide catalyst differentiates between the in-situ generating P-species in the A-T process, mainly involving phosphoryl chloride and phosphoric anhydride, thus leading to highly enantiodivergent O-phosphorylation reactions; and furthermore hydrogen bonding interactions between the catalysts and phosphorus molecules were crucial in asymmetric induction.
-
Asymmetric synthesis of benzothiazolopyrimidines with high catalytic efficiency and stereoselectivity under bifunctional Phosphonium Salt systems
Chemical communications (Cambridge England), 2020Co-Authors: Jianke Pan, Xue Chen, Xiaoyu Ren, Tian-li WangAbstract:An efficient formal [4+2] annulation between 2-benzothiazolimines and allenoates mediated by an amino acid-derived bifunctional Phosphonium Salt catalyst is developed. This protocol provides a new and facile synthetic approach to create a broad range of isothiourea-based benzothiazolopyrimidine derivatives under mild reaction conditions with high isolated yields and excellent diastereo- and enantioselectivities.
-
enantioselective synthesis of multifunctionalized 4h pyrans via formal 4 2 annulation process by bifunctional Phosphonium Salt catalysis
Organic Letters, 2020Co-Authors: Jianke Pan, Chunhui Jiang, Xiaoxia Wang, Xuemei Wang, Tian-li WangAbstract:A highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional Phosphonium Salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to >20:1 dr, up to >99.9% ee). The utility and the practicality of this method were demonstrated by the gram-scale reaction and facile elaboration. Of note, this is the first example of an asymmetric annulation reaction involving allenic reactants under a phase-transfer catalysis system.
-
Enantioselective Synthesis of Multifunctionalized 4H-Pyrans via Formal [4 + 2] Annulation Process by Bifunctional Phosphonium Salt Catalysis
Organic letters, 2019Co-Authors: Jianke Pan, Chunhui Jiang, Xiaoxia Wang, Xuemei Wang, Tian-li WangAbstract:A highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional Phosphonium Salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to >20:1 dr, up to >99.9% ee). The utility and the practicality of this method were demonstrated by the gram-scale reaction and facile elaboration. Of note, this is the first example of an asymmetric annulation reaction involving allenic reactants under a phase-transfer catalysis system.
-
Asymmetric synthesis of spiro-structural 2,3-dihydrobenzofurans via the bifunctional Phosphonium Salt-promoted [4 + 1] cyclization of ortho-quinone methides with α-bromoketones
Organic Chemistry Frontiers, 2019Co-Authors: Song Zhang, Jianke Pan, Chunhui Jiang, Hong-su Zhang, Tian-li WangAbstract:We report a practical and scalable method for the highly diastereo- and enantio-selective construction of 2,3-dihydrobenzofurans bearing spiro-structures by means of cyclization reactions between ortho-quinone methides and α-bromoketones through bifunctional Phosphonium Salt catalysis under mild conditions. A variety of spiro-fused 2,3-dihydrobenzofuran derivatives were readily synthesized in high yields with excellent diastereo- and enantio-selectivities (up to >20 : 1 dr and 97% ee). This protocol represents an alternative facile way for preparing biologically important chiral 2,3-dihydrobenzofurans. Moreover, mechanistic observations indicated that the hydrogen bonding interaction between the Bronsted acid moiety of the Phosphonium catalyst and the “CO” unit of the quinone is crucial for stereoinduction.
Gang Zhao - One of the best experts on this subject based on the ideXlab platform.
-
asymmetric cyclizations via a sequential michael addition conia ene reaction by combining multifunctional quaternary Phosphonium Salt and silver catalysis
Tetrahedron, 2019Co-Authors: Guosheng Fang, Changwu Zheng, Dongdong Cao, Lu Pan, Hongyu Wang, Gang Zhao, Haoran HongAbstract:Abstract A one-pot asymmetric Michael addition/Conia-ene reaction sequence, catalyzed by combination of a dipeptide-derived multifunctional quaternary Phosphonium Salt and Ag2CO3 has been developed, which provides a series of synthetically important chiral methylenecyclopentane derivatives in moderate to excellent yields (up to 97%) and enantioselectivities (up to 93%).
-
Asymmetric Total Synthesis of Vincadifformine Enabled by a Thiourea-Phosphonium Salt Catalyzed Mannich-Type Reaction.
Chemistry (Weinheim an der Bergstrasse Germany), 2019Co-Authors: Lu Pan, Changwu Zheng, Hao‐ran Hong, Guo‐sheng Fang, Jun Liu, Gang ZhaoAbstract:An asymmetric total synthesis of vincadifformine is described. The limited tactics with chiral cation-directed catalysis in total synthesis inspired the development of our strategy for accessing this alkaloid in enantionrich form. The route features a thiourea-Phosphonium Salt catalyzed Mannich-type reaction, a phosphine-promoted aza-Morita-Baylis-Hillman reaction and a trifluoroacetic acid promoted deprotection/amidation cascade process.
-
Asymmetric cyclizations via a sequential Michael addition/Conia-ene reaction by combining multifunctional quaternary Phosphonium Salt and silver catalysis
Tetrahedron, 2019Co-Authors: Guosheng Fang, Changwu Zheng, Dongdong Cao, Lu Pan, Hao‐ran Hong, Hongyu Wang, Gang ZhaoAbstract:Abstract A one-pot asymmetric Michael addition/Conia-ene reaction sequence, catalyzed by combination of a dipeptide-derived multifunctional quaternary Phosphonium Salt and Ag2CO3 has been developed, which provides a series of synthetically important chiral methylenecyclopentane derivatives in moderate to excellent yields (up to 97%) and enantioselectivities (up to 93%).
-
Nucleophilic monofluoroalkylation with fluorinated Phosphonium Salt toward carbonyl and imine compounds
Journal of Fluorine Chemistry, 2017Co-Authors: Xian-liang Zeng, Gang Zhao, Zuyong Deng, Can Liu, Jin-hong Lin, Xing Zheng, Ji-chang XiaoAbstract:Abstract A fluorinated substituent on the positive phosphorus in Phosphonium Salt [Ph3P+CF(Me)CO2Et Br−] was found to be able to act as a nucleophile to realize monofluoroalkylation of aldehydes, ketones and imines.
-
Enantioselective Construction of Spirocyclic Oxindoles via Tandem Michael/Michael Reactions Catalyzed by Multifunctional Quaternary Phosphonium Salt.
The Journal of organic chemistry, 2016Co-Authors: Jia-xing Zhang, Changwu Zheng, Dongdong Cao, Hongyu Wang, Gang Zhao, Yongjia ShangAbstract:The enantioselective construction of five-membered spirocyclic oxindoles via a double Michael cascade reaction is described by using dipeptide-based multifunctional quaternary Phosphonium Salt catalysts. The desired products were obtained in excellent yields (up to 94%) and good to high stereoselectivities (up to >19:1 dr and 99% ee).
Chunhui Jiang - One of the best experts on this subject based on the ideXlab platform.
-
enantioselective synthesis of multifunctionalized 4h pyrans via formal 4 2 annulation process by bifunctional Phosphonium Salt catalysis
Organic Letters, 2020Co-Authors: Jianke Pan, Chunhui Jiang, Xiaoxia Wang, Xuemei Wang, Tian-li WangAbstract:A highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional Phosphonium Salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to >20:1 dr, up to >99.9% ee). The utility and the practicality of this method were demonstrated by the gram-scale reaction and facile elaboration. Of note, this is the first example of an asymmetric annulation reaction involving allenic reactants under a phase-transfer catalysis system.
-
Enantioselective Synthesis of Multifunctionalized 4H-Pyrans via Formal [4 + 2] Annulation Process by Bifunctional Phosphonium Salt Catalysis
Organic letters, 2019Co-Authors: Jianke Pan, Chunhui Jiang, Xiaoxia Wang, Xuemei Wang, Tian-li WangAbstract:A highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional Phosphonium Salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to >20:1 dr, up to >99.9% ee). The utility and the practicality of this method were demonstrated by the gram-scale reaction and facile elaboration. Of note, this is the first example of an asymmetric annulation reaction involving allenic reactants under a phase-transfer catalysis system.
-
Asymmetric synthesis of spiro-structural 2,3-dihydrobenzofurans via the bifunctional Phosphonium Salt-promoted [4 + 1] cyclization of ortho-quinone methides with α-bromoketones
Organic Chemistry Frontiers, 2019Co-Authors: Song Zhang, Jianke Pan, Chunhui Jiang, Hong-su Zhang, Tian-li WangAbstract:We report a practical and scalable method for the highly diastereo- and enantio-selective construction of 2,3-dihydrobenzofurans bearing spiro-structures by means of cyclization reactions between ortho-quinone methides and α-bromoketones through bifunctional Phosphonium Salt catalysis under mild conditions. A variety of spiro-fused 2,3-dihydrobenzofuran derivatives were readily synthesized in high yields with excellent diastereo- and enantio-selectivities (up to >20 : 1 dr and 97% ee). This protocol represents an alternative facile way for preparing biologically important chiral 2,3-dihydrobenzofurans. Moreover, mechanistic observations indicated that the hydrogen bonding interaction between the Bronsted acid moiety of the Phosphonium catalyst and the “CO” unit of the quinone is crucial for stereoinduction.
-
asymmetric synthesis of spiro structural 2 3 dihydrobenzofurans via the bifunctional Phosphonium Salt promoted 4 1 cyclization of ortho quinone methides with α bromoketones
Organic chemistry frontiers, 2019Co-Authors: Song Zhang, Jianke Pan, Chunhui Jiang, Hong-su Zhang, Tian-li WangAbstract:We report a practical and scalable method for the highly diastereo- and enantio-selective construction of 2,3-dihydrobenzofurans bearing spiro-structures by means of cyclization reactions between ortho-quinone methides and α-bromoketones through bifunctional Phosphonium Salt catalysis under mild conditions. A variety of spiro-fused 2,3-dihydrobenzofuran derivatives were readily synthesized in high yields with excellent diastereo- and enantio-selectivities (up to >20 : 1 dr and 97% ee). This protocol represents an alternative facile way for preparing biologically important chiral 2,3-dihydrobenzofurans. Moreover, mechanistic observations indicated that the hydrogen bonding interaction between the Bronsted acid moiety of the Phosphonium catalyst and the “CO” unit of the quinone is crucial for stereoinduction.
-
Asymmetric Three-Component Cyclizations toward Structurally Spiro Pyrrolidines via Bifunctional Phosphonium Salt Catalysis.
Organic letters, 2019Co-Authors: Lixiang Zhu, Jianke Pan, Xiaoyu Ren, Zhongxiu Liao, Chunhui Jiang, Tian-li WangAbstract:Asymmetric multicomponent reactions toward optically pure compounds are highly attractive but extremely challenging. Presented herein is a highly diastereo- and enantioselective three-component cyclization of exocyclic alkenes with aldehydes and amino esters, which was enabled by bifunctional Phosphonium Salt catalysts. A wide range of multiply substituted spiro pyrrolidine derivatives were prepared in high yields with excellent stereoselectivities. Of note, this is the first example of a catalytic asymmetric three-component reaction with a phase-transfer catalysis system.
Jianke Pan - One of the best experts on this subject based on the ideXlab platform.
-
Enantiodivergent Kinetic Resolution of 1,1'-Biaryl-2,2'-Diols and Amino Alcohols by Dipeptide-Phosphonium Salt Catalysis Inspired by the Atherton-Todd Reaction.
Angewandte Chemie (International ed. in English), 2021Co-Authors: Siqiang Fang, Jianke Pan, Xiaoyu Ren, Jian-ping Tan, Yuan Chen, Hongkui Zhang, Tian-li WangAbstract:Herein, we disclose a highly enantiodivergent organocatalytic protocol towards the synthesis of atropisomeric biaryls, through a kinetic resolution inspired by dipeptide-Phosphonium Salt-catalyzed Atherton-Todd (A-T) reaction. This flexible approach led to both R- and S-enantiomers by fine-tuning of bifunctional Phosphonium with excellent selectivity factors (s) of up to 1057 and 525, respectively. The potential of newly synthesized O-phosphorylated biaryl diols was illustrated by providing a platform for the synthesis of axially chiral organophosphorus compounds. Mechanistic investigations suggest that the bifunctional Phosphonium halide catalyst differentiates between the in-situ generating P-species in the A-T process, mainly involving phosphoryl chloride and phosphoric anhydride, thus leading to highly enantiodivergent O-phosphorylation reactions; and furthermore hydrogen bonding interactions between the catalysts and phosphorus molecules were crucial in asymmetric induction.
-
Asymmetric synthesis of benzothiazolopyrimidines with high catalytic efficiency and stereoselectivity under bifunctional Phosphonium Salt systems
Chemical communications (Cambridge England), 2020Co-Authors: Jianke Pan, Xue Chen, Xiaoyu Ren, Tian-li WangAbstract:An efficient formal [4+2] annulation between 2-benzothiazolimines and allenoates mediated by an amino acid-derived bifunctional Phosphonium Salt catalyst is developed. This protocol provides a new and facile synthetic approach to create a broad range of isothiourea-based benzothiazolopyrimidine derivatives under mild reaction conditions with high isolated yields and excellent diastereo- and enantioselectivities.
-
enantioselective synthesis of multifunctionalized 4h pyrans via formal 4 2 annulation process by bifunctional Phosphonium Salt catalysis
Organic Letters, 2020Co-Authors: Jianke Pan, Chunhui Jiang, Xiaoxia Wang, Xuemei Wang, Tian-li WangAbstract:A highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional Phosphonium Salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to >20:1 dr, up to >99.9% ee). The utility and the practicality of this method were demonstrated by the gram-scale reaction and facile elaboration. Of note, this is the first example of an asymmetric annulation reaction involving allenic reactants under a phase-transfer catalysis system.
-
Enantioselective Synthesis of Multifunctionalized 4H-Pyrans via Formal [4 + 2] Annulation Process by Bifunctional Phosphonium Salt Catalysis
Organic letters, 2019Co-Authors: Jianke Pan, Chunhui Jiang, Xiaoxia Wang, Xuemei Wang, Tian-li WangAbstract:A highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional Phosphonium Salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to >20:1 dr, up to >99.9% ee). The utility and the practicality of this method were demonstrated by the gram-scale reaction and facile elaboration. Of note, this is the first example of an asymmetric annulation reaction involving allenic reactants under a phase-transfer catalysis system.
-
Asymmetric synthesis of spiro-structural 2,3-dihydrobenzofurans via the bifunctional Phosphonium Salt-promoted [4 + 1] cyclization of ortho-quinone methides with α-bromoketones
Organic Chemistry Frontiers, 2019Co-Authors: Song Zhang, Jianke Pan, Chunhui Jiang, Hong-su Zhang, Tian-li WangAbstract:We report a practical and scalable method for the highly diastereo- and enantio-selective construction of 2,3-dihydrobenzofurans bearing spiro-structures by means of cyclization reactions between ortho-quinone methides and α-bromoketones through bifunctional Phosphonium Salt catalysis under mild conditions. A variety of spiro-fused 2,3-dihydrobenzofuran derivatives were readily synthesized in high yields with excellent diastereo- and enantio-selectivities (up to >20 : 1 dr and 97% ee). This protocol represents an alternative facile way for preparing biologically important chiral 2,3-dihydrobenzofurans. Moreover, mechanistic observations indicated that the hydrogen bonding interaction between the Bronsted acid moiety of the Phosphonium catalyst and the “CO” unit of the quinone is crucial for stereoinduction.
Yongjia Shang - One of the best experts on this subject based on the ideXlab platform.
-
Enantioselective Construction of Spirocyclic Oxindoles via Tandem Michael/Michael Reactions Catalyzed by Multifunctional Quaternary Phosphonium Salt.
The Journal of organic chemistry, 2016Co-Authors: Jia-xing Zhang, Changwu Zheng, Dongdong Cao, Hongyu Wang, Gang Zhao, Yongjia ShangAbstract:The enantioselective construction of five-membered spirocyclic oxindoles via a double Michael cascade reaction is described by using dipeptide-based multifunctional quaternary Phosphonium Salt catalysts. The desired products were obtained in excellent yields (up to 94%) and good to high stereoselectivities (up to >19:1 dr and 99% ee).
-
enantioselective construction of spirocyclic oxindoles via tandem michael michael reactions catalyzed by multifunctional quaternary Phosphonium Salt
Journal of Organic Chemistry, 2016Co-Authors: Jia-xing Zhang, Changwu Zheng, Dongdong Cao, Hongyu Wang, Gang Zhao, Yongjia ShangAbstract:The enantioselective construction of five-membered spirocyclic oxindoles via a double Michael cascade reaction is described by using dipeptide-based multifunctional quaternary Phosphonium Salt catalysts. The desired products were obtained in excellent yields (up to 94%) and good to high stereoselectivities (up to >19:1 dr and 99% ee).