Decarboxylation via Addition of Water to a Carboxyl Group: Acid Catalysis of Pyrrole-2-Carboxylic Acid
2009; American Chemical Society; Volume: 131; Issue: 33 Linguagem: Inglês
10.1021/ja905196n
ISSN1943-2984
AutoresScott O. C. Mundle, Ronald Kluger,
Tópico(s)Organic Chemistry Cycloaddition Reactions
ResumoThe decarboxylation of pyrrole-2-carboxylic acid is subject to acid catalysis in strongly acidic solutions. Protonation of the pyrrole ring at C2 produces a potentially low-energy carbanion leaving group. Carbon dioxide formation is suppressed by the requisite formation of its high-energy conjugate acid. As a result, decarboxylation must proceed via an associative mechanism through the addition of water to the carboxyl group of the protonated reactant, leading to the formation of pyrrole and protonated carbonic acid, which rapidly dissociates into H(3)O(+) and carbon dioxide.
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