Given its wide variety of applications in the pharmaceutical industry, the synthesis of imidazo[1,2-a]pyridines has been extensively studied since the beginning of the last century. Here, we disclose the mechanism for the synthesis of imidazo[1,2-a]pyridines by means of the Ortoleva-King reaction. We also reveal the reaction pathway leading to the formation of an iodinated byproduct, demonstrating the challenge of preventing the formation of such a byproduct because of its low energy barrier to access. Moreover, quantum chemistry tools were employed to investigate the mechanism of intramolecular proton transfer in the excited state, and connections with aromaticity were explored.

中文翻译：

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揭示2-(2'-羟基苯基)咪唑并[1,2-a]吡啶的合成和激发态分子内质子转移的反应机理

鉴于咪唑并[1,2-a]吡啶在制药工业中的广泛应用，自上世纪初以来，咪唑并[1,2-a]吡啶的合成已得到广泛研究。在这里，我们公开了通过Ortoleva-King反应合成咪唑并[1,2-a]吡啶的机理。我们还揭示了导致碘化副产物形成的反应途径，证明了防止这种副产物形成的挑战，因为其低能垒。此外，利用量子化学工具研究了激发态分子内质子转移的机制，并探索了与芳香性的联系。