In Situ Generated, Tetracoordinated Copper(II)‐Quinoline Complexes as Photocatalysts for the Chlorosulfonylation of Alkenes and Alkynes
Pawittra Chaibuth, Sebastian Engl, Alexander Reichle, Kittipong Chainok, Mongkol Sukwattanasinitt, Oliver Reiser
Abstract
Abstract A series of copper complexes was synthesized and studied as photocatalysts for the chlorosulfonylation of olefins. Featuring a tetradentate ligand consisting of one amino quinoline and two methyl pyridine moieties, the resulting Cu(II)‐complex is effective under visible light irradiation to add sulfonyl chlorides to alkenes and alkynes, including unactivated aliphatic olefins. A weak base additive such as Na 2 CO 3 prevents catalyst poisoning, resulting in an improvement of reaction yields and catalyst lifetime. A broad scope of sulfonyl chlorides and alkenes/alkynes as coupling partners are amenable for the title process, including examples previously reported unsuccessful with established copper‐based photocatalysts.