A General Synthesis of Vinyl Azides from Olefins. Stereochemistry of Elimination from β-iodo Azides

Treatment with base of β-iodo azides, prepared by the addition of iodine azide to olefins, resulted generally in vinyl azides, suggesting a directive effect of the azido function. Terminal olefins, vicinally disubstituted olefins, and unsaturated carbonyl compounds all led regiospecifically to the vinyl azides. Indene, 1,2-dihydronaphthalane, cyclooctene, and 1,3-cyclooctadiene also gave the vinyl azides. However, the iodine azide adducts of cyclopentene and cyclohexene produced the allyl azides. Apparently, the stereoelectronic preference for trans elimination is greater than the directive effect of the azido function. An assignment of cis configuration to the double bond in the eight-membered-ring vinyl azides, made on the basis of nmr data, suggests syn elimination of hydrogen iodide in these systems. Regioselectivity in IN₃ additions to olefins is discussed.