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Intramolecular activation of imidate with cationic gold(I) catalyst: A new benzylation reaction of alcohols. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fujita H, Kakuyama S, Fukuyoshi S, Hayakawa N, Oda A, Kunishima M. Triazine-Based Cationic Leaving Group: Synergistic Driving Forces for Rapid Formation of Carbocation Species. J Org Chem 2018; 83:4568-4580. [PMID: 29616811 DOI: 10.1021/acs.joc.8b00331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new triazine-based cationic leaving group has been developed for the acid-catalyzed alkylation of O- and C-nucleophiles. There are two synergistic driving forces, namely, stable C═O bond formation and charge-charge repulsive effects, involved in the rapid generation of the carbocation species in the presence of trifluoromethanesulfonic acid (∼200 mol %). Considerable rate acceleration of benzylation, allylation, and p-nitrobenzylation was observed as compared to the reactions with less than 100 mol % of the acid catalyst. The triazine-based leaving group showed superior p-nitrobenzylation yield and stability in comparison to common leaving groups, trichloroacetimidate and bromide. A plausible reaction mechanism (the cationic leaving group pathway) was proposed on the basis of mechanistic and kinetic studies, NMR experiments, and calculations.
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Affiliation(s)
- Hikaru Fujita
- Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical, and Health Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Satoshi Kakuyama
- Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical, and Health Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Shuichi Fukuyoshi
- Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical, and Health Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Naoko Hayakawa
- Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical, and Health Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Akifumi Oda
- Graduate School of Pharmacy , Meijo University , 150 Yagotoyama , Tempaku-ku, Nagoya , Aichi 468-8503 , Japan
| | - Munetaka Kunishima
- Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical, and Health Sciences , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
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