Direct coupling of ethers and acylhalides was promoted by a binary catalytic system comprising an Ir-based photocatalyst and a Ni complex under blue-light irradiation. Photocatalysts with high triplet energy directed the catalysis, and the reaction likely proceeded by triplet–triplet energy transfer from the excited photocatalysts. Chlorine radicals generated from an excited Ni complex bearing a Ni–Cl
A nitrite-catalyzed ring contraction reaction of substituted tetrahydrofurans by oxidation of bromide under aerobic conditions as a dehydrogenative dual functionalization was developed to provide 2-acyltetrahydrofurans in good yields. On the other hand, the oxidation reaction of 1-substituted isochromans occurred via the bromohydroxylation to give 1-(dibromoalkyl)-1-hydroxyisochromans in high yields