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.
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
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
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
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
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
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 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.
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.