We report decarboxylative carbonyl alpha-arylation by coupling of arylboron nucleophiles with malonic acid derivatives. This process is enabled by the merger of aerobic oxidative Cu catalysis with decarboxylative enolate interception reminiscent of malonyl-CoA reactivity in polyketide biosynthesis. This method enables the synthesis of monoaryl acetate derivatives containing electrophilic functional groups that are incompatible with existing alpha-arylation reactivity paradigms. The utility of the reaction is demonstrated in drug intermediate synthesis and late-stage functionalization.