Metal-free synthesis of 1,N(6)-ethenoadenines from N(6)-propargyl-adenines via NIS mediated radical cascade reaction

In the present paper, an efficient approach for the construction of 1,N(6)-ethenoadenines from conveniently prepared N(6)-propargyl-adenines is developed. This reaction merges N-iodosuccinimide radical initiation and aerobic aminooxygenation in dioxane. This mild, 5-exo-dig, and metal-free cascade reaction could be applied to a wide substrate scope to provide 1,N(6)-ethenoadenines in moderate to good yields. The reaction mechanism was proposed and tested using radical inhibitor (butylated hydroxytoluene) and isotopic labelling ((18)O(2)) experiments.