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 (18O2) experiments.