Stereospecific Introduction of Azide Functions into Organic Molecules

Iodine azide prepared in situ by the reaction of sodium azide and iodine monochloride in acetonitrile has been shown to add in good yield and in a highly stereospecific manner to a variety of unsaturated systems. Thus, cyclohexene and 2-cholestene produce the trans and the trans-diaxial adduct, respectively; straight-chain cis and trans olefins give respectively the threo and erythro adducts; terminal olefins form adducts where the azido function is at the 2 position; and conjugated olefins such as 1,2-dihydronaphthalene lead to products with the azido function occupying the benzylic position. Tolane and 1,3-cyclooctadiene yield one-to-one adducts; conjugated ketones and esters give adducts where the azido function occupies the β position; and isonitriles give iodotetrazoles. Possible mechanisms for these reactions are discussed.