A Route to Enantiopure (O‑Methyl)6‑2,6-Helic[6]arenes: Synthesis of Hexabromo-Substituted 2,6-Helic[6]arene Derivatives and Their Suzuki–Miyaura Coupling Reactions
A route to enantiopure (O-methyl)6-2,6-helic[6]arenes (+)-P-2 and (−)-M-2 has been provided. By the reaction of enantiopure triptycene precursors (+)-1 and (−)-1 in refluxed o-DCB for 12 h in the presence of catalytic amount of FeCl3, and then followed by treatment of the obtained oligomers under...
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Published in | Journal of organic chemistry Vol. 83; no. 19; pp. 11532 - 11540 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
05.10.2018
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Online Access | Get full text |
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Summary: | A route to enantiopure (O-methyl)6-2,6-helic[6]arenes (+)-P-2 and (−)-M-2 has been provided. By the reaction of enantiopure triptycene precursors (+)-1 and (−)-1 in refluxed o-DCB for 12 h in the presence of catalytic amount of FeCl3, and then followed by treatment of the obtained oligomers under the same conditions, (+)-P-2 and (−)-M-2 could be obtained in 51% and 53% total yield, respectively. It was also found that racemic and enantiopure (O-methyl)6-2,6-helic[6]arenes could be easily brominated by Br2 to give the corresponding hexabromo-substituted helic[6]arene derivatives rac-4, (+)-P-4, and (−)-M-4 in high yields. The crystal structure of (+)-P-4 further confirmed the absolute configuration of the helic[6]arenes and their derivatives. Moreover, a series of hexaaryl-substituted helic[6]arene derivatives 5a–f with deepened cavities could be conveniently synthesized in 55–71% yield by Suzuki–Miyaura coupling reactions of 4 and arylboronic acids. rac-5a could encapsulate chloroform and exhibit self-sorting stacking in solid state. Enantiopure (+)-P-5a–f and (−)-M-5a–f showed mirror images in their CD spectra. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-3263 1520-6904 |
DOI: | 10.1021/acs.joc.8b01437 |