Ten chirai mesogenic compounds containing fluorinated alkyl terminal tails were prepared and characterized by IR, NMR, MS. The phase transition behavior was investigated by DSC and polarized optical microscope. Two-ri...Ten chirai mesogenic compounds containing fluorinated alkyl terminal tails were prepared and characterized by IR, NMR, MS. The phase transition behavior was investigated by DSC and polarized optical microscope. Two-ring liquid crystal compounds exhibited no mesogenic phase or only a monotropic smectic A phase. The longer fluori- natal alkyl chain on the three-ring was advantageous to the formation of smectic phase. The mesogens with chiral center located between fluorinated tail and mesogenic core exhibited chiral smectic C phase and other smectic phases when the alkoxyl adhering to the other side of the mesogenic core was of intermediate length.展开更多
A selective monodefluorinative alkylation of 3,3-difluorooxindoles is achieved.The reaction starts by the attack of a 4-dimethylaminopyrine-boryl radical to the carbonyl oxygen atom of 3,3-difluorooxindoles,followed b...A selective monodefluorinative alkylation of 3,3-difluorooxindoles is achieved.The reaction starts by the attack of a 4-dimethylaminopyrine-boryl radical to the carbonyl oxygen atom of 3,3-difluorooxindoles,followed by a spin-center shift to generate radical intermediates with the elimination of a fluoride anion.The subsequent radical addition to alkenes affords a range of 3-alkyl-fluorooxindoles products.The strategy offers access to C-3 functionalized oxindoles with wide substrate scope and tolerates a wide range of functional groups.展开更多
文摘Ten chirai mesogenic compounds containing fluorinated alkyl terminal tails were prepared and characterized by IR, NMR, MS. The phase transition behavior was investigated by DSC and polarized optical microscope. Two-ring liquid crystal compounds exhibited no mesogenic phase or only a monotropic smectic A phase. The longer fluori- natal alkyl chain on the three-ring was advantageous to the formation of smectic phase. The mesogens with chiral center located between fluorinated tail and mesogenic core exhibited chiral smectic C phase and other smectic phases when the alkoxyl adhering to the other side of the mesogenic core was of intermediate length.
基金We thank the National Natural Science Foundation of China(Nos.21971226 and 22171253)the Anhui Provincial Natural Science Foundation(No.2108085MB59)the Fundamental Research Funds for the Central Universities(No.WK2060000017)for financial support.
文摘A selective monodefluorinative alkylation of 3,3-difluorooxindoles is achieved.The reaction starts by the attack of a 4-dimethylaminopyrine-boryl radical to the carbonyl oxygen atom of 3,3-difluorooxindoles,followed by a spin-center shift to generate radical intermediates with the elimination of a fluoride anion.The subsequent radical addition to alkenes affords a range of 3-alkyl-fluorooxindoles products.The strategy offers access to C-3 functionalized oxindoles with wide substrate scope and tolerates a wide range of functional groups.
