A convenient silver-catalyzed decarboxylative cascade radical cyclization of tertiary carboxylic acids and o-(allyloxy)arylaldehydes was developed to synthesize 3-alkyl-substituted chroman-4-one derivatives. A series of chroman-4-one derivatives were constructed with moderate to good yields. This procedure offers a practical method for the synthesis of 3-alkyl-substituted chroman-4-one derivatives by a one-pot reaction from easily available reagents.