Tandem β-Elimination/Hetero-Michael Addition Rearrangement of an N-Alkylated Pyridinium Oxime to an O-Alkylated Pyridine Oxime Ether: An Experimental and Computational Study
| Autor: | Igor Picek, Primož Šket, Robert Vianello, Blaženka Foretić, Janez Plavec |
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| Rok vydání: | 2015 |
| Předmět: |
Alkylation
Molecular Structure Pyridines Stereochemistry Kornblum–DeLaMare rearrangement Organic Chemistry Pyridinium Compounds Ether Sigmatropic reaction Oxime Medicinal chemistry chemistry.chemical_compound Tandem reactions Pyridine oxime ether Reaction mechanisms Rearrangement chemistry Cascade reaction Oximes Pyridine Michael reaction Quantum Theory Thermodynamics Pyridinium Ethers |
| Zdroj: | The Journal of Organic Chemistry. 80:2165-2173 |
| ISSN: | 1520-6904 0022-3263 |
| Popis: | A novel OH(-)-promoted tandem reaction involving C(β)-N(+)(pyridinium) cleavage and ether C(β)-O(oxime) bond formation in aqueous media has been presented. The study fully elucidates the fascinating reaction behavior of N-benzoylethylpyridinium-4-oxime chloride in aqueous media under mild reaction conditions. The reaction journey begins with the exclusive β-elimination and formation of pyridine-4-oxime and phenyl vinyl ketone and ends with the formation of O-alkylated pyridine oxime ether. A combination of experimental and computational studies enabled the introduction of a new type of rearrangement process that involves a unique tandem reaction sequence. We showed that (E)-O-benzoylethylpyridine-4-oxime is formed in aqueous solution by a base-induced tandem β-elimination/hetero-Michael addition rearrangement of (E)-N-benzoylethylpyridinium-4-oximate, the novel synthetic route to this engaging target class of compounds. The complete mechanistic picture of this rearrangement process was presented and discussed in terms of the E1cb reaction scheme within the rate-limiting β-elimination step. |
| Databáze: | OpenAIRE |
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