Ru(II)-Catalyzed peri -C–H Activation with Strained Alkylidene β-Lactones and β-Lactams: Selective Access to Seven- and Four-Membered Heterocycles

A Ru(II)-catalyzed peri-C–H activation of α-naphthols with strained alkylidene β-lactones and β-lactams is reported. With alkylidene β-lactones, the reaction proceeds via controlled strain release, favoring an allylic substitution pathway to afford a broad range of seven-membered oxepines in high yields. In contrast, the corresponding β-lactams suppress this reactivity and undergo Heck-type functionalization, leading to functionalized β-lactams. The protocol is operationally simple and scalable, displays a broad substrate scope, and can be extended to distal functionalization of indoles. The synthetic utility of this method is highlighted through downstream product diversification, which further enhances the scaffold diversity.