RhIII-Catalyzed Dehydrogenative Coupling of Quinoline N-Oxides with Alkenes: N-Oxide as Traceless Directing Group for Remote C-H Activation

A Rh-III-catalyzed dehydrogenative coupling reaction of quinoline N-oxides with alkenes has been developed that provides C-8 olefinated quinoline derivatives by employing a remote C-H activation strategy. Main features of this catalytic method include the use of N-oxide as a traceless directing group, the high selectivity of the reaction for the C-8 position, and the broad scope of possible substrates. Mechanistic studies have also been performed. A five-membered rhodacycle of quinoline N-oxide, a possible key reaction intermediate, was synthesized and characterized for the first time.