Taming Chlorine Azide: Access to 1,2-Azidochlorides from Alkenes

The
in situ preparation and trapping of chlorine azide provided
a versatile one-pot method for the azidochlorination of alkenes. Gaseous
ClN3 generated from sodium azide, hypochlorite, and acetic
acid can be explosive if isolation is attempted. Instead, we generated
the reagent in biphasic media in the presence of olefinic compounds
dissolved in the organic layer or evenly emulsified throughout the
solution in the absence of organic solvent. Under these conditions,
ClN3 is created slowly and trapped immediately at the aqueous–organic
interface. The resulting safe and reliable procedure provided 1,2-azidochloride
derivatives of a variety of substrates, with evidence for both polar
and radical mechanisms. Minor impurities characterized in the product
mixtures indicated the presence of alternative reaction pathways deriving
primarily from radical intermediates.