Photochemical Branched Hydrothiocarbonylation of Vinyl Arenes with DHP-Thioesters

We describe for the first time a photochemical branched hydrothiocarbonylation of vinyl arenes with bench-stable 1,4-dihydropyridine thioesters to furnish various thioesters in high regioselectivity. 4CzIPN assists in the activation of DHP-thioester precursors. The Pd/phosphine catalyst system plays a role in harnessing reactivity and achieving site-selectivity. In this mild and scalable method, various thioesters can be obtained with good functional group tolerance, including late-stage thioesterification to deliver drug-conjugates. A branched hydroselenocarbonylation of styrene is also achieved with DHP-selenoester to afford the selenoester.