On the mechanism of ketene three-component reaction

Ketene three-component reaction (K-3CR) and silylative ketene three-component reaction (SK-3CR) are valuable multicomponent transformations for the efficient synthesis of α-acyloxy- and α-silyloxyacrylamides, structural motifs frequently found in bioactive compounds and strategically important synthetic intermediates. In this study, a combined investigation employing density functional theory (DFT) calculations and mass spectrometry monitoring experiments provides a detailed and consistent description of the full reaction pathways involved in both transformations. The results elucidate the principal elementary steps, intermediates, and divergence points between the K-3CR and SK-3CR, offering a unified mechanistic framework that aligns and rationalizes experimental observations reported in the literature. • DFT and ESI-MS reveal complete reaction pathway for Ketene three-component reaction. • Key steps, intermediates, and divergence points are outlined. • A distinct mechanism is unveiled for Silylative three-component variant. • A unified mechanism rationalizes reported experimental data.