Copper‐Catalyzed N‐Alkyl Formamide Activation: Tandem Oxidative Coupling Approach for the Construction of C−N and C−O Bonds to Synthesize 3‐Alkyl‐1,3‐Benzoxazine‐2,4‐Dione and 4‐Methylene‐3‐Alkyl‐1,3‐Benzoxazine‐2‐One Derivatives

N‐alkyl formamide activation by using of copper/oxidant system via tandem/domino reaction pathway to construct C−N/C−O bond formation is reported. This protocol elucidated a method for the synthesis of pharmaceutically interested 3‐alkyl‐1,3‐benzoxazine‐2,4‐dione and 1,3‐methylene‐3‐alkyl‐benzoxazine‐2‐one derivatives without the aid of toxic chemicals such as phosgene or its derivatives.