Monodentate Transient Directing Group Assisted Pd-Catalyzed Direct Dehydrogenative Cross-Coupling of Benzaldehydes with Arenes toward 9‑Fluorenones

Commercially available 3,5-bis­(trifluoromethyl)­aniline was found to be a highly efficient monodentate transient directing group (MonoTDG) for the palladium-catalyzed direct dehydrogenative cross-coupling of benzaldehydes with arenes. A diverse set of symmetrical and unsymmetrical 9-fluorenones was readily obtained in yields of 32–72% along with excellent regioselectivities and broad functional group compatibility as well as high atom economy under mild conditions via a dual carbon–hydrogen (C–H) bond activation sequence.