Rh(III)-Catalyzed Cascade Nucleophilic Addition/Annulation of 2-Diazo-1,3-diketones with 1,3-Dicarbonyl Compounds To Access 6,7-Dihydrobenzofuran-4(5)-ones.

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(5)-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 N and HO as byproducts. Moreover, the method described is scalable and adaptable to late-stage functionalization.