Enols, Diamino Enols, and Breslow Intermediates: A Comparative Quantum Chemical Analysis

Abstract

Breslow intermediates (BIs) are generally referred as diamino enols, however, there are subtle differences between enols, diamino enols, and Breslow intermediates. Quantum chemical analysis has been carried out to establish the differences among the three classes of compounds. Electronic structure details, charge distribution, bond dissociation energies, etc. were analyzed in a few BIs and compared with that of enols and diamino enols. Energy decomposition analysis has been carried out to establish the variation in the C–C bond character among these systems. There are clear differences among the three classes of the compounds, though there are a few overlaps. A few systems which were earlier considered as BIs do not exhibit the expected characteristics.