Multiphoton Multicomponent Reactions: Discovery of the 2‐Photon Ketene 4‐Component Reaction (2P‐K‐4CR)

Herein, the first multiphoton, multicomponent approach for synthesizing highly functionalized oxetanes using diazoketones, isocyanides, silanols (or carboxylic acids), and 1,2-dicarbonyl derivatives (benzils) is presented as starting materials. Blue light irradiation initiates the Wolff rearrangement of diazoketones, generating ketenes that promptly react with isocyanides and silanols (or carboxylic acids) to afford captodative olefins. Concurrently, excitation of benzils promotes a [2 + 2] photocycloaddition between the activated carbonyl group and the captodative olefin. This newly developed two-photon ketene four-component reaction has been thoroughly investigated, also through chemometric analysis, including its substrates scope and the extension to mixed benzils. Furthermore, the observed stereochemical outcomes, validated by X-Ray diffraction analysis, are elucidated through detailed computational studies, providing insights into the underlying reaction mechanism.