Bidirectional Elongation Strategy Using Ambiphilic Radical Linchpin for Modular Access to 1,4-Dicarbonyls via Sequential Photocatalysis

Published: May 22, 2023

Organic molecules that can be connected with multiple substrates by sequential C−C bond formations utilized as linchpins in multicomponent processes. While they are useful for rapidly increasing molecular complexity, most of the reported linchpin coupling methods rely on use organometallic species strong carbon nucleophiles to form bonds, which narrows functional group compatibility. Here, we describe a metal-free, radical-mediated approach using formyl-stabilized phosphonium ylide multifunctional under visible-light photoredox conditions. The present method uses ambiphilic character ylide, serves both nucleophilic and an electrophilic carbon-centered radical source. stepwise controllable generation these intermediates allows photocatalysis involving two mechanistically distinct additions, initiated same photocatalyst one pot high functional-group tolerance. methodology enables bidirectional assembly electronically differentiated alkene fragments thus offers rapid modular access 1,4-dicarbonyl compounds versatile synthetic intermediates.

Language: Английский

Dual Photosensitizer Cycles Working Synergistically in a C(sp)‐C(sp³) Cross‐Coupling Reaction**

Asian Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 12(10)

Published: Aug. 16, 2023

Abstract To assess the value and reactivity of new photocatalysts (PCs), their performance should be evaluated in one or more established reactions benchmarked against using known PCs. Here, we our recently developed PC, pDTCz‐DPmS , a C(sp)‐C(sp 3 ) cross‐coupling reaction that had been documented literature. Previous findings indicated this could not proceed absence PC; however, under conditions was case. Without moderate product yield obtained, while increased significantly upon addition . UV‐Vis absorption studies Hantzsch ester (HE) additive acting as competitive absorber light from excitation source, quenching confirmed HE quenched by radical precursor, N ‐(acyloxy)phthalimide. Mechanistic investigations two parallel photosensitization pathways were operation; reductive photocatalytic pathway (using sacrificial photoreductant (employing HE). These work synergistically to enhance target product.

Language: Английский