Access to Some C5-Cyclised 2-Pyrones and 2-Pyridones via Direct Arylation; Retention of Chloride as a Synthetic Handle

The synthetic effort towards the functionalisation of C–H bonds on 2-pyrones and 2-pyridones has been enabled by the preferential reactivity of the C-3 position. Herein, we report a direct arylation protocol for the intramolecular coupling of 2-pyrones and 2-pyridones, allowing access to a previously unavailable class of C-5 cyclised products with an unstudied biological profile. A C–Cl bond was retained at C-3 during the direct arylation process allowing further derivatisation at C-3, using a Suzuki–Miyaura cross-coupling reaction.