Unlocking regioselective meta-alkylation with epoxides and oxetanes via dynamic kinetic catalyst control

Regioselective arene C−H bond alkylation is a powerful tool in synthetic chemistry, yet subject to many challenges. Herein, we report the meta -C−H bond alkylation of aromatics bearing N -directing groups using (hetero)aromatic epoxides as alkylating agents. This method results in complete regioselectivity on both the arene as well as the epoxide coupling partners, cleaving exclusively the benzylic C−O bond. Oxetanes, which are normally unreactive, also participate as alkylating reagents under the reaction conditions. Our mechanistic studies reveal an unexpected reversible epoxide ring opening process undergoing catalyst-controlled regioselection, as key for the observed high regioselectivities. Regioselective arene C−H bond alkylation is a powerful tool in synthetic chemistry, yet subject to many challenges. Here, the authors report the meta-C−H bond alkylation of aromatics bearing N-directing groups using (hetero)aromatic epoxides as alkylating agents.