Photochemical Synthesis of Ynones from Aryl Aldehydes and Sulfone-Based Alkynes

Ynones are attractive molecular building blocks owing to their electrophilic character, which can be exploited in a variety of functionalization strategies, giving rise to valuable reaction products. This work presents a photochemical strategy for the direct generation of ynones from aldehydes and substituted alkynes bearing radicofugal groups, such as sulfones. Using TBADT (tetrabutylammonium decatungstate) as a photocatalyst, the direct photochemical synthesis of a variety of ynones is achieved in high yields and short reaction times. Exploiting a continuous flow reactor setup thereby provides for higher photon flux and scalability to generate gram quantities of the desired products. The beneficial effect of acetone as a cosolvent is reported, which minimizes double addition of the acyl radical generated from the aldehyde building blocks. Overall, this method represents an efficient and chemoselective route toward valuable ynones that may find further applications in industrial settings.