Decarboxylation via addition of water to a carboxyl group: acid catalysis of pyrrole-2-carboxylic acid.
The 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.
Mundle
Scott O C
SO
Davenport Chemical Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
Kluger
Ronald
R