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Synthesis of Bridging Chiral p–tert ‐Butylcalix[4]arenes with One and Two Carbamoyl Bridge‐Substituents through Anionic Ortho‐Fries Rearrangement
Author(s) -
Ma Hao,
Weng XiuFang,
Ren ShanShan,
Tang ZiYing,
Peng XinBang,
He Yong,
Zheng Shuang,
Li ShaoYong
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202000891
Subject(s) - substituent , chemistry , fries rearrangement , enantiomer , yield (engineering) , stereochemistry , medicinal chemistry , crystal structure , crystallography , catalysis , organic chemistry , materials science , metallurgy
Bridging chiral p ‐ tert ‐butylcalix[4]arenes ( p ‐ t ‐Bu‐BCC's) with different N ‐substituted carbamoyl bridge‐substituents ( N , N ‐dimethylcarbamoyl, N , N ‐diethylcarbamoyl and morpholinocarbonyl) were successfully prepared through anionic ortho‐Fries rearrangement from mono‐ O ‐carbamates of 1,3‐dipropyl‐ p‐tert‐ butylcalix[4]arene in 65–75% yield. In addition, p ‐ t ‐Bu ‐ BCC with two N , N ‐dimethylcarbamoyl bridge‐substituents was produced by this method from mono‐ O ‐carbamate of p ‐ t ‐Bu ‐ BCC with one N , N ‐dimethylcarbamoyl bridge‐substituent in 71% yield. However, the synthesis of p ‐ t ‐Bu ‐ BCC with additional carbamoyl bridge‐substituents using this method could not be attempted, as the required rearrangement precursor failed to be synthesized. Finally, the racemic p ‐ t ‐Bu ‐ BCC with morpholinocarbonyl bridge‐substituent was optically resolved into a pair of enantiomers, whose absolute configurations were determined through ROESY analysis and ECD comparison.