Efficient access to 8 H -isoquinolino[1,2- b ]quinazolin-8-ones and phthalazino[2,3- a ]cinnoline-8,13-diones through cyclic amide-directed Ru(II)/Ir(III)-catalyzed C–H bond activation, has been developed. Consecutive C–H bond activation, carbene insertion, and condensation annulation processes were realized, affording 8 H -isoquinolino[1,2- b ]quinazolin-8-one and phthalazino[2,3- a ]cinnoline-8,13-dione derivatives in good-to-excellent yields under mild conditions, with H 2 O and N 2 being generated as the only byproducts.

A Rh­(III)-catalyzed cascade nucleophilic addition/intramolecular annulation of 2-diazo-1,3-diketones with 1,3-dicarbonyl compounds (e.g., 1,3-diketones and β-keto esters) is achieved to afford 6,7-dihydrobenzofuran-4­(5H)-ones in up to 91% yields. Notably, a wide range of substrates and functional groups were well-tolerated under the optimized reaction conditions to give desired products in moderate to excellent yields with release of N2 and H2O as byproducts. Moreover, the method described is scalable and adaptable to late-stage functionalization.

A variety of pyran-fused isoquinoline derivatives were prepared in moderate to good yields through the rhodium-catalyzed dual C-H functionalization/annulation of methyl benzimidates and diazo compounds. A one-pot procedure, broad substrate scope, diversified products, and mild reaction conditions make this transformation a powerful tool for the synthesis of fused heteroarenes. In addition, the synthetic application was extended by large-scale synthesis and late-stage functionalization via Pd-catalyzed Suzuki-Miyaura, Heck, and Sonogashira cross-coupling reaction. Furthermore, a photophysical survey reveals that the pyran-fused isoquinoline products exhibit fluorescence properties and show potential for exploring fluorescent material applications.

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An effective and operationally simple one-pot strategy has been developed for the synthesis of unsymmetrical urea derivatives via sequential three-component reactions of cyclic 2-dizao-1,3-diketones with carbodiimides and 1,2-dihaloethane.