From Esters to Ketones via a Photoredox‐Assisted Reductive Acyl Cross‐Coupling Strategy

Abstract A method was developed for ketone synthesis via a photoredox‐assisted reductive acyl cross‐coupling (PARAC) using a nickel/photoredox dual‐catalyzed cross‐electrophile coupling of two different carboxylic acid esters. A variety of aryl, 1°, 2°, 3°‐alkyl 2‐pyridyl esters can act as acyl electrophiles while N ‐(acyloxy)phthalimides (NHPI esters) act as 1°, 2°, 3°‐radical precursors. Our PARAC strategy provides an alternative and reliable way to synthesize various sterically congested 3°‐3°, 3°‐2°, and aryl‐3° ketones under mild and highly unified conditions, which have been otherwise difficult to access. The combined experimental and computational studies identified a Ni 0 /Ni I /Ni III pathway for ketone formation.