The Norrish type II reaction is an interesting photochemical process through Csp3-H functionalization of N,N-disubstituted oxo-amine or oxo-amide provides access to diverse synthetic building blocks by different pathw...The Norrish type II reaction is an interesting photochemical process through Csp3-H functionalization of N,N-disubstituted oxo-amine or oxo-amide provides access to diverse synthetic building blocks by different pathways.Due to the finite lifetime of the excited state and rapid changes in the intermediates,there are significant challenges in controlling the stereochemical outcomes of this reaction over the strong racemic background reaction.The oxazolidin-4-one skeleton is a useful structural motif found in bioactive molecules,and it is the one that is produced by a not well-studied route among the three routes in Norrish type II cyclization.Herein we report the asymmetric version of this process,and a variety of oxazolidin-4-ones is achieved from arylα-oxoamides via triplet excimers with three H-transfer steps interspersed by a cyclization step under mild,visible light.In the presence of chiral N,N-dioxide/metal complex catalysts,diastereo-and enantiocontrol in this photochemical reaction happens with enantioselective protonation of enol intermediates as the crucial stereo-determining step,getting the better of the thermodynamical control pathway.Trans-oxazolidine-4-ones can be obtained in high enantioselectivity,which can be transferred into optically active cis-oxazolidine-4-ones after the treatment with a base.展开更多
（S）-4-Phenyl-2-oxazolidinone imprinted polymers were prepared by using methacrylic acid （MAA） as the functional monomer, and divinylbenzene （DVB） as crosslinker. The factors, which influence the selectivity of t...（S）-4-Phenyl-2-oxazolidinone imprinted polymers were prepared by using methacrylic acid （MAA） as the functional monomer, and divinylbenzene （DVB） as crosslinker. The factors, which influence the selectivity of the polymers were explored. Effective separation was observed for racemic 4-phenyl-2-oxazolidinone in mobile phase of acetonitrile. The investigation of mobile phase suggested that the hydrogen bonds between template and functional monomer was a primary factor in chiral recognition, while the preparation of polymers implied that the л-л stacking interaction between template and crosslinker played a role in imprinting procedure.展开更多
4-Methylene-1,3-oxazolidin-2-ones can be synthesized from propargylic alcohols, primary amines and carbon dioxide under supercritical condition in the absence of any additional catalyst and solvent. Various propargyli...4-Methylene-1,3-oxazolidin-2-ones can be synthesized from propargylic alcohols, primary amines and carbon dioxide under supercritical condition in the absence of any additional catalyst and solvent. Various propargylic alcohols and primary amines were examined.展开更多
基金the financial support of the National Natural Science Foundation(grant no.22188101)the Science and Technology Department of Sichuan Province(grant no.2021YJ0561)Sichuan University(grant no.2020SCUNL204)for financial support.
文摘The Norrish type II reaction is an interesting photochemical process through Csp3-H functionalization of N,N-disubstituted oxo-amine or oxo-amide provides access to diverse synthetic building blocks by different pathways.Due to the finite lifetime of the excited state and rapid changes in the intermediates,there are significant challenges in controlling the stereochemical outcomes of this reaction over the strong racemic background reaction.The oxazolidin-4-one skeleton is a useful structural motif found in bioactive molecules,and it is the one that is produced by a not well-studied route among the three routes in Norrish type II cyclization.Herein we report the asymmetric version of this process,and a variety of oxazolidin-4-ones is achieved from arylα-oxoamides via triplet excimers with three H-transfer steps interspersed by a cyclization step under mild,visible light.In the presence of chiral N,N-dioxide/metal complex catalysts,diastereo-and enantiocontrol in this photochemical reaction happens with enantioselective protonation of enol intermediates as the crucial stereo-determining step,getting the better of the thermodynamical control pathway.Trans-oxazolidine-4-ones can be obtained in high enantioselectivity,which can be transferred into optically active cis-oxazolidine-4-ones after the treatment with a base.
基金financed by the National Natural Science Foundation of China(No.20202015).
文摘（S）-4-Phenyl-2-oxazolidinone imprinted polymers were prepared by using methacrylic acid （MAA） as the functional monomer, and divinylbenzene （DVB） as crosslinker. The factors, which influence the selectivity of the polymers were explored. Effective separation was observed for racemic 4-phenyl-2-oxazolidinone in mobile phase of acetonitrile. The investigation of mobile phase suggested that the hydrogen bonds between template and functional monomer was a primary factor in chiral recognition, while the preparation of polymers implied that the л-л stacking interaction between template and crosslinker played a role in imprinting procedure.
基金supported financially by Youth Foundation of Guangdong Medical College(No.XQ1029)Science and Technology Planning Project of Zhanjiang city(No.2009c3103024)
文摘4-Methylene-1,3-oxazolidin-2-ones can be synthesized from propargylic alcohols, primary amines and carbon dioxide under supercritical condition in the absence of any additional catalyst and solvent. Various propargylic alcohols and primary amines were examined.
