Aldehydes as Carbon Radical Acceptors: Silver Nitrate Catalyzed Cascade Decarboxylation and Oxidative Cyclization toward Dihydroflavonoid Derivatives

Silver nitrate-catalyzed cascade decarboxylation and oxidative cyclization of alpha-oxocarboxylic acids, alkenes, and aldehydes is demonstrated for the first time. With ammonium persulfate as the oxidant, the cascade reactions afford dihydroflavonoid derivatives as products in moderate to good yields, exhibiting a broad substrate tolerance. Control experiments indicated that the mechanism includes a radical pathway with aldehydes as the carbon radical acceptors.