A simple,practical and eco-friendly visible light-induced alkylation of N-sulfonyl ketamine under metal-,additive-,external photocatalyst-free conditions was developed.This photocatalytic method utilized low cost and ...A simple,practical and eco-friendly visible light-induced alkylation of N-sulfonyl ketamine under metal-,additive-,external photocatalyst-free conditions was developed.This photocatalytic method utilized low cost and abundant alkanes as the atom economy alkyl sources with H2O2as the environmentally beneficial oxidant,allowing for the efficient construction of diverse valuable 4-alkylated sulfonyl ketamines.The N-sulfonyl ketamine played a dual role of reactant and photocatalyst,thus simplifying the reaction system.展开更多
Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophil...Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophiles such as aldehydes and ketones in these addition reactions has been a challenge due to the inherent difficulty of benzylic deprotonation.In this study,we present a novel approach for the construction of N-sulfonyl amines via rhodium-catalyzed addition of unbiased benzylic C–H bonds to cyclic N-sulfonyl ketamines throughπ-coordination.This strategy enables the synthesis of a diverse range of N-sulfonyl amines,and subsequent diversification of the addition products showcases the synthetic potential of this protocol.展开更多
The metal-free combination of catalytic amounts of PPh3,B（C6F5）3,and PhSiH_3 can efficiently hydrosilylate aldehydes, ketones,aldimines and ketimines to afford the corresponding reduction products in good yields.
Benzosultams exhibit antibacterial,antidiabetic,and anticancer activities,yet synthesizing chiral spirocyclic sultams remains challenging.To overcome this issue,we developed a photoinduced cocatalyzed asymmetric[3+2]a...Benzosultams exhibit antibacterial,antidiabetic,and anticancer activities,yet synthesizing chiral spirocyclic sultams remains challenging.To overcome this issue,we developed a photoinduced cocatalyzed asymmetric[3+2]annulation of N-sulfonyl ketimines and alkynes to access these structures.This methodology delivers diverse chiral spirocyclic sultams in high yields(up to 95%)and enantioselectivity(up to 98%ee)under mild reaction conditions.Additionally,mechanistic studies reveal that oxidative addition may be the rate-determining step.Our methodology broadens the applications of synergistic photoredox/Co catalysis and offers a sustainable route to pharmaceutically relevant chiral sultams.展开更多
The asymmetric Pudovik reaction of chiral fluoroalkyl α,β-unsaturated ketimines derivated from(R)-tert-butanesulfinamide and diphenyl phosphite was achieved in the presence of Rb2CO3 at room temperature.A series of ...The asymmetric Pudovik reaction of chiral fluoroalkyl α,β-unsaturated ketimines derivated from(R)-tert-butanesulfinamide and diphenyl phosphite was achieved in the presence of Rb2CO3 at room temperature.A series of fluoroalkylated α-amino phosphonates were prepared in good yields with high diastereoselectivities.展开更多
Construction of biologically interesting tryptanthrin-derived N,O-ketals was enabled via Cu(II)-catalyzed enantioselective addition of alcohols and tert-butyl hydroperoxide to tryptanthrin-derived N-Boc ketimines.Ster...Construction of biologically interesting tryptanthrin-derived N,O-ketals was enabled via Cu(II)-catalyzed enantioselective addition of alcohols and tert-butyl hydroperoxide to tryptanthrin-derived N-Boc ketimines.Stereoselective activation of the electrophiles was possible using structurally confined chiral catalysts although such electrophiles suffered from the drawbacks such as low reactivity or steric hindrance around the reaction center.The protocol tolerated variations in both the tryptanthrin part and the alcohol scopes,and the products could be obtained with up to 99%ee and in up to 99%yield.Gram-scale reaction was possible,and functional group transformations could also be realized.X-ray diffraction experiments confirmed the configuration of tryptanthrin-derived N-Boc ketimine as well as the absolute configuration of the product.展开更多
A series of α-amino acids are obtained in 72-96% optical yields by alkylation of the ketimine derived from(+)-2-hydroxy-pinan-3-one and(-)-menthyl glycinate fol- lowed by hydrolysis of the alkylated intermediates wit...A series of α-amino acids are obtained in 72-96% optical yields by alkylation of the ketimine derived from(+)-2-hydroxy-pinan-3-one and(-)-menthyl glycinate fol- lowed by hydrolysis of the alkylated intermediates with mineral acid.The double asymmetric induction are explained by the transition model of lithium enolate.展开更多
Alkylation of the ketimine 2 obtained from condensation of (+)-ketopinic acid and benzyla- mine with a variety of alkylating agents gives the products whose trends in diastereomeric excesses (1- 100% O. P.) appear to ...Alkylation of the ketimine 2 obtained from condensation of (+)-ketopinic acid and benzyla- mine with a variety of alkylating agents gives the products whose trends in diastereomeric excesses (1- 100% O. P.) appear to correlate with the structure and reactivity of electrophilic agents. Using excess n-butyl lithium and allylic or benzylic halides, β-alkylation occured.展开更多
Asymmetric syntheses of (S)-α-amino acids in 28--98% optical yields via double chiral induction in alkylations of ketimine 1 derived from (+)-2-hydroxypinan-3-one and (-)-men- thyl glycinate which is a chiral match p...Asymmetric syntheses of (S)-α-amino acids in 28--98% optical yields via double chiral induction in alkylations of ketimine 1 derived from (+)-2-hydroxypinan-3-one and (-)-men- thyl glycinate which is a chiral match pair have been studied. The factors controlling the diastereoselec- tivities in alkylation reactions of the ketimine, the properties of alkylating agents and various alkylation conditions are examined.展开更多
基金financial support from the University of South China。
文摘A simple,practical and eco-friendly visible light-induced alkylation of N-sulfonyl ketamine under metal-,additive-,external photocatalyst-free conditions was developed.This photocatalytic method utilized low cost and abundant alkanes as the atom economy alkyl sources with H2O2as the environmentally beneficial oxidant,allowing for the efficient construction of diverse valuable 4-alkylated sulfonyl ketamines.The N-sulfonyl ketamine played a dual role of reactant and photocatalyst,thus simplifying the reaction system.
基金the National Natural Science Foundation of China(Nos.22271235,22071198)the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2022SDXHDX0006)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(No.2020R01004)for research support。
文摘Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophiles such as aldehydes and ketones in these addition reactions has been a challenge due to the inherent difficulty of benzylic deprotonation.In this study,we present a novel approach for the construction of N-sulfonyl amines via rhodium-catalyzed addition of unbiased benzylic C–H bonds to cyclic N-sulfonyl ketamines throughπ-coordination.This strategy enables the synthesis of a diverse range of N-sulfonyl amines,and subsequent diversification of the addition products showcases the synthetic potential of this protocol.
文摘The metal-free combination of catalytic amounts of PPh3,B（C6F5）3,and PhSiH_3 can efficiently hydrosilylate aldehydes, ketones,aldimines and ketimines to afford the corresponding reduction products in good yields.
基金the National Science Foundation of China(grant nos.22371085,22471089,22271113,and 92256301)the Fundamental Research Funds for the Central Universities(grant nos.CCNU24JCPT018 and CCNU24JCPT013)Central China Normal University and Wuhan Institute of Photochemistry and Technology for support of this research.
文摘Benzosultams exhibit antibacterial,antidiabetic,and anticancer activities,yet synthesizing chiral spirocyclic sultams remains challenging.To overcome this issue,we developed a photoinduced cocatalyzed asymmetric[3+2]annulation of N-sulfonyl ketimines and alkynes to access these structures.This methodology delivers diverse chiral spirocyclic sultams in high yields(up to 95%)and enantioselectivity(up to 98%ee)under mild reaction conditions.Additionally,mechanistic studies reveal that oxidative addition may be the rate-determining step.Our methodology broadens the applications of synergistic photoredox/Co catalysis and offers a sustainable route to pharmaceutically relevant chiral sultams.
基金Financial support from the National Natural Science Foundation of China(No.21172243)is gratefully acknowledged.
文摘The asymmetric Pudovik reaction of chiral fluoroalkyl α,β-unsaturated ketimines derivated from(R)-tert-butanesulfinamide and diphenyl phosphite was achieved in the presence of Rb2CO3 at room temperature.A series of fluoroalkylated α-amino phosphonates were prepared in good yields with high diastereoselectivities.
基金supports from the National Natural Science Foundation of China(21672106).
文摘Construction of biologically interesting tryptanthrin-derived N,O-ketals was enabled via Cu(II)-catalyzed enantioselective addition of alcohols and tert-butyl hydroperoxide to tryptanthrin-derived N-Boc ketimines.Stereoselective activation of the electrophiles was possible using structurally confined chiral catalysts although such electrophiles suffered from the drawbacks such as low reactivity or steric hindrance around the reaction center.The protocol tolerated variations in both the tryptanthrin part and the alcohol scopes,and the products could be obtained with up to 99%ee and in up to 99%yield.Gram-scale reaction was possible,and functional group transformations could also be realized.X-ray diffraction experiments confirmed the configuration of tryptanthrin-derived N-Boc ketimine as well as the absolute configuration of the product.
基金This work was supported by the National Natural Science Foundation of China
文摘A series of α-amino acids are obtained in 72-96% optical yields by alkylation of the ketimine derived from(+)-2-hydroxy-pinan-3-one and(-)-menthyl glycinate fol- lowed by hydrolysis of the alkylated intermediates with mineral acid.The double asymmetric induction are explained by the transition model of lithium enolate.
基金The subject was supported by the National Natural Science Foundation of China
文摘Alkylation of the ketimine 2 obtained from condensation of (+)-ketopinic acid and benzyla- mine with a variety of alkylating agents gives the products whose trends in diastereomeric excesses (1- 100% O. P.) appear to correlate with the structure and reactivity of electrophilic agents. Using excess n-butyl lithium and allylic or benzylic halides, β-alkylation occured.
基金the National Natural Science Foundation of China.
文摘Asymmetric syntheses of (S)-α-amino acids in 28--98% optical yields via double chiral induction in alkylations of ketimine 1 derived from (+)-2-hydroxypinan-3-one and (-)-men- thyl glycinate which is a chiral match pair have been studied. The factors controlling the diastereoselec- tivities in alkylation reactions of the ketimine, the properties of alkylating agents and various alkylation conditions are examined.
