Rh(III)-Catalyzed Redox-Neutral C-H Activation/[3 + 2] Annulation of -Phenoxy Amides with Propargylic Monofluoroalkynes.

An efficient and redox-neutral Rh(III)-catalyzed C-H activation/[3 + 2] annulation of -phenoxy amides with propargylic monofluoroalkynes has been realized to afford 3-alkylidene dihydrobenzofurans with an interesting α-quaternary carbon center. Combined experimental and computational mechanistic studies revealed that a Rh(III)-Rh(V)-Rh(III) catalytic pathway/uncatalyzed intramolecular [H···F] bonding-assisted S2'-type substitution cascade might be involved in the catalytic cycle, thereby enabling an excellent site-/regioselectivity with broad substrate/functional group compatibility, including the complete retention of the highly strained cyclobutyl structure in the 3-position.