Photocatalyzed Dehydrogenation of Aliphatic N-Heterocycles Releasing Dihydrogen

We report the iridium–nickel dual photocatalytic acceptorless and redox neutral dehydrogenation of aliphatic heterocycles yielding cyclic alkenes without overoxidation at room temperature. Excitation of the iridium photocatalyst initiates the formation of a nickel hydride intermediate that yields alkenes and H2 via β-hydride elimination. The reaction proceeds regioselectively and the scope was demonstrated by the synthesis of 12 biologically relevant molecules and drugs. In addition, commercially and easily available N-heterocyclic alkane starting materials were converted into functionalized alkenes of high synthetic and commercial value using the method.