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Breaking the Aromaticity Trap: N-Silylation-Induced Formation of Stable 2,3-Dihydro-4-dialkylaminopyridin-1-iums
Verkhov, Valery A., Yakubenko, Artyom A.
, Begović, Benjamin, Tupikina, Elena Yu.
and Antonov, Alexander S.
(2026)
Breaking the Aromaticity Trap: N-Silylation-Induced Formation of Stable 2,3-Dihydro-4-dialkylaminopyridin-1-iums.
The Journal of Organic Chemistry.
Date of publication of this fulltext: 02 Jul 2026 14:16
Article
DOI to cite this document: 10.5283/epub.79749
Abstract
The reactivity of pyridines toward organolithium reagents is dominated by the nucleophilic addition to the C2 position, leading to the formation of labile 1,2-dihydropyridines that readily rearomatize. Herein, we report an unexpected deviation from this classical pathway. Trimethylsilylation of 4-dialkylaminopyridine steers their reaction with alkyl lithium reagents (n-BuLi, s-BuLi, t-BuLi) ...
The reactivity of pyridines toward organolithium reagents is dominated by the nucleophilic addition to the C2 position, leading to the formation of labile 1,2-dihydropyridines that readily rearomatize. Herein, we report an unexpected deviation from this classical pathway. Trimethylsilylation of 4-dialkylaminopyridine steers their reaction with alkyl lithium reagents (n-BuLi, s-BuLi, t-BuLi) toward the formation of 2,3-dihydro-4-dialkylaminopyridin-1-iums, isolated as air-stable triflates, which are remarkably resistant to oxidation and deprotonation. This stability is attributed to pronounced orbital interactions and charge delocalization between the NR2 group and the pyridinium core creating a vinylogous amidine structural motif. At the same time, triisopropylsilylation completely suppresses nucleophilic addition, enabling the first case of room-temperature C2 lithiation of the pyridine core. This difference in the reaction pathway originated from a dramatic decrease of the relative steric accessibility of C2(6) pyridine carbon atoms.
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Details
| Item type | Article | ||||
| Journal or Publication Title | The Journal of Organic Chemistry | ||||
| Publisher: | ACS | ||||
|---|---|---|---|---|---|
| Open Access Type: | ACS Hybrid | ||||
| Date | 25 June 2026 | ||||
| Institutions | Chemistry and Pharmacy > Institut für Organische Chemie Chemistry and Pharmacy > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind | ||||
| Projects |
Funded by:
Deutsche Forschungsgemeinschaft (DFG)
(426795949)
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| Identification Number |
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| Keywords | Addition reactions, Chemical reactions, Nitrogen, Pyridines, Reagents | ||||
| Dewey Decimal Classification | 500 Science > 540 Chemistry & allied sciences | ||||
| Status | Published | ||||
| Refereed | Yes, this version has been refereed | ||||
| Created at the University of Regensburg | Yes | ||||
| URN of the UB Regensburg | urn:nbn:de:bvb:355-epub-797497 | ||||
| Item ID | 79749 |
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