Photoredox Decarboxylative C(sp³)–N Coupling of α-Diazoacetates with Alkyl <i>N</i>-Hydroxyphthalimide Esters for Diversified Synthesis of Functionalized <i>N</i>-Alkyl Hydrazones

Abstract

Herein we report a metal-free photocatalytic coupling reaction for the synthesis of structurally and functionally diverse <i>N</i>-alkyl hydrazones from α-diazoacetates and <i>N</i>-alkyl hydroxyphthalimide esters. By employing Rose Bengal as a photocatalyst with yellow LEDs irradiation, over 60 <i>N</i>-alkyl hydrazones were synthesized. Fluorescence quenching analysis and deuterium incorporation experiments reveal that Hantzsch ester serves as both an electron donor and proton source for the reaction. This strategy offers a simple retrosynthetic disconnection for conventionally inaccessible C(sp³)-rich <i>N</i>-alkyl hydrazones.