Photoirradiation-Promoted ipso -Azidation of 1-Aryltriazenes

Ultraviolet (UV) irradiation (λ_max = 370 nm) of a methanol solution of 1-aryltriazenes and azidotrimethylsilane promotes ipso-azidation. Optimization of the reaction conditions and a mechanistic study revealed that the hydrazoic acid generated in situ enabled efficient transformation. The high functional group tolerance of this reaction allowed for the transformation of a broad range of 1-aryltriazenes, including those introduced on a protein, to the corresponding aryl azides.