Palladium(II)-catalyzed direct ortho-C-H acylation of anilides by oxidative cross-coupling with aldehydes using tert-butyl hydroperoxide as oxidant

An efficient palladium-catalyzed C-H acylation with aldehydes using tert-butyl hydroperoxide (TBHP) transforms various anilides into synthetically useful 2-aminobenzophenone derivatives under mild conditions (40°C, 3 h). The acylation reaction exhibits excellent regioselectivity and functional group tolerance, and simple aromatic aldehydes, functionalized aliphatic aldehydes and heteroaromatic aldehydes are effective coupling partners. The acylation reaction is probably initiated by a rate-limiting electrophilic C-H cyclopalladation (kH/kD=3.6; ρ+=-0.74) to form an arylpalladium complex, followed by acyl radical functionalization.