Visible Light Mediated Co-Catalyzed Isocyanide Insertion with Sulfonyl Azide: Synthesis of Sulfonyl Carbamimidic Azide and Sulfonyl Aminotetrazole via Carbodiimide Intermediate.

Herein, we report an operationally simple and efficient protocol to prepare sulfonyl carbamimidic azide and N-sulfonyl aminotetrazole via Co-catalyzed three component coupling of sulfonyl azide (acts as nitrene source), isocyanide, and TMS-azide at room temperature under visible light. Initially, the carbamimidic azide is formed, which cyclizes only in the presence of base to deliver N-sulfonyl aminotetrazole in very good yields. The sulfonyl aminotetrazole can also be synthesized directly without isolating the carbamimidic azide in the presence of base. The sulfonyl azide is anticipated to generate nitrene and reacts with isocyanide to produce carbodiimide. Subsequent addition of azide (TMS-N3 ) to carbodiimide results in the formation of carbamimidic azide.