Rh-Catalyzed Intramolecular Hydroarylation of Unactivated Alkenes via C-C Bond Activation

The transition-metal-catalyzed intramolecular hydroarylation of alkenes has been recognized as a straightforward approach for the construction of 3,3-disubstituted 2,3-dihydrobenzofurans. The reactions mainly rely on the reductive Heck reaction of aryl halides or the direct C-H bond activation of arenes bearing a directing group. This work realizes the Rh-catalyzed intramolecular hydroarylation of olefin-tethered benzocyclobutenols via C-C bond activation, which offers an alternative approach to 3,3-disubstituted 2,3-dihydrobenzofurans bearing a 4-beta-keto moiety. The methodology features 100% atom economy and pH-and redox-neutral conditions, and is applicable to the late-stage functionalization of complex molecules. The asymmetric variant has also been achieved with excellent enantioselectivities.