2‐oxo‐2H‐chromen‐7‐olate Catalyzed C−C and C−N Bond Formations in Visible Light

Abstract 7‐hydroxycoumarin is a naturally occurring compound with useful biological and fluorescent properties. In this work, we demonstrate a base‐assisted photoactivation of 7‐hydroxycoumarin in blue LED and its potential in enabling C−C and C−N bond formations. 7‐hydroxycoumarin, on deprotonation with Cs 2 CO 3 forms 2‐oxo‐2 H ‐chromen‐7‐olate which exhibits photoreductant properties and mediates arylation and hydroxyarylation using hypervalent iodonium ylides; alkylation using N ‐hydroxyphthalimide esters; and amination with primary and secondary amines. The strategy does not require any additional metal or organic dye‐based photocatalyst and offers a good functional group tolerance giving the C−C and C−N coupled products in moderate to good yields.