Theoretical studies to predict the utility of diazo esters in their reactions with 1,4-quinones: experimental validation via a visible light driven metal free process

Abstract

We report here theoretical and experimental studies that revealed two distinct modes of reactivity of 1,4-quinones (benzoquinone [BQ], 2-methyl benzoquinone [MBQ], naphthoquinone [NQ], and anthraquinone [AQ]) with electronically different alkyl-2-diazoalkylnoates and aryl diazo acetates (electron acceptor–electron donor), methyl diazo acetates (electron acceptor) and dialkyl-2-diazomalonate (electron acceptor–electron acceptor) under blue LEDs. Depending on the substrate–reactant combination, the reaction either happens at the CC region or the CO region of 1,4-quinones to provide a diverse variety of aryl vinyl ethers, spiro epoxides, and cyclopropanated and CH-alkylated quinones. Computational studies based on density functional theory calculations predicted the reaction outcomes which were later corroborated via experimentation.