Ir(III)-Catalyzed Dual C-H Activation of 2-Aryl Phthalazinediones and 3-Aryl-2 H -benzo[ e ][1,2,4]thiadiazine-1,1-dioxides for the Construction of Spiro-Fused Cyclic Frameworks.

An Ir(III)-catalyzed double C-H activation strategy has been developed for the synthesis of highly rigid spiro frameworks by means of ortho -functionalization of 2-aryl phthalazinediones and 2,3-diphenylcycloprop-2-en-1-ones using the Ir(III)/AgSbF 6 catalytic system. Similarly, 3-aryl-2 H -benzo[ e ][1,2,4]thiadiazine-1,1-dioxides undergo smooth cyclization with 2,3-diphenylcycloprop-2-en-1-ones to afford a diverse range of spiro compounds in good yields with excellent selectivity. Additionally, 2-arylindazoles provide the corresponding chalcone derivatives under similar reaction conditions.