Iodine azide, reactions with unsaturated

The addition of iodine azide to double bonds gives p-iodo azides. The reagent can be prepared in situ from KI—NaNa in the presence of Oxone -wet alumina. The addition is stereospecific and anti, suggesting that the mechanism involves a cyclic iodonium ion intermediate. The reaction has been performed on many double-bond compounds, including allenes and a,p-unsaturated ketones. Similar reactions can be performed with BrNa and CfNa. 1,4-Addition has been found with acyclic conjugated dienes. In the case of BrNa, both electrophilic and free-radical mechanisms are important, whUe with CIN3 the addi-... 

The general method for synthesizing 4 -azido-2 -deoxynucleosides has been previously described and is depicted in Scheme I. Selective iodination at the 5 -position of the starting 2 -deoxynucleosides with triphenylphosphine, iodine and pyridine in dioxane, followed by sodium methoxide induced elimination, afforded the 4, 5 -unsaturated derivatives. The addition of iodine azide across the double bond was carried out by first preparing a solution of iodine azide in DMF via the reaction of iodine monochloride with excess sodium azide. To this freshly prepared solution was added the unsaturated... 

With substrates featuring a more energetic, multiply unsaturated polarized bonding scheme, like carbodiimides or isocyanides, a [2+2] cycloaddition reaction to the C=Y bond subsequent to the preliminary nucleophilic attack of the benzyl ligand could be observed [68] (Scheme 17). The same cycloaddition was also observed with those substrates and the corresponding iodinated yttrium complex, which also reacted with tert-butyl phosphaalkyne [67]. However, no subsequent [2+2] cycloaddition was observed with pivalonitrile or adamantly azide on the benzylated complex. 

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