Unveiling Heavier Dihydropyridine Chalcogenol Esters in Metallaphotoredox Catalyst-Enabled Regioselective Hydrothio(seleno)carbonylation

Herein, aromaticity-driven thio(seleno)ester group transfer from novel 1,4-dihydropyridine thio(seleno)esters to alkene feedstocks is disclosed by merging palladium and photoredox catalysis. In this process, photoactivation of dihydropyridine thio(seleno)esters is integrated with regioselective hydrometalation of alkenes, avoiding photoinduced Pd-C bond homolysis of organopalladium intermediates. Additionally, a regioselective hydroselenocarbonylation of an alkene is accomplished for the first time using a bench-stable selenoester reagent. The activation mode of novel dihydropyridine thioesters has been illustrated by detailed mechanistic studies, spectroscopic analysis, intermediate trapping, and isotope labeling experiments.