53782-51-7Relevant academic research and scientific papers
A Nucleophilic Activation of Carboxylic Acids by Proline: Oxa-Michael Addition to Methyl Vinyl Ketone under Solvent-Free Conditions
Jha, Ajit Kumar,Inani, Heena,Easwar, Srinivasan
supporting information, p. 1473 - 1477 (2017/07/22)
A serendipitous nucleophilic activation of carboxylic acids by proline helped to achieve a direct hydrocarboxylation of methyl vinyl ketone at 60 °C under solvent-free conditions. A variety of carboxylic acids were used successfully in this oxa-Michael addition, affording useful 4-acyloxy-2-butanones in moderate yields. The reactions are carried out under solvent-free conditions, and the products are isolated in high purity by a simple work-up procedure without any need for column chromatographic purification, imparting a green quotient to the protocol. A heterodimeric non-covalent interaction between the amino acid and the carboxylic acid appears to be the most plausible mechanistic interpretation for the nucleophilic activation; additionally, the possible activation of the Michael acceptor by iminium ion formation presents an interesting case of proline acting as a bifunctional catalyst.
