Iodine azide alkenes

Iodine azide, 1N3, adds to alkenes by an electrophilic mechanism similar to that of bromine. If a monosubstituted alkene such as 1-butene is used, only one product results ... 

In the case of electrophilic addition, the reactions of tricyclic dienes 1 with several electrophilic reagents have been investigated.1 7 Interestingly, some of these compounds undergo addition reactions with remarkable syn stereoselectivity. For example, the reaction of dimethyl tricy-clo[4.2.2.02,5]deca-3,9-diene-7,8-dicarboxylate with iodine azide solution, prepared in situ from an excess of sodium azide and iodine monochloride, in acetonitrile at — 5 C provided the. yyn-4-azido-3-iodo derivative 2 (Table 1) in 90% yield.1,2,4,6 The formation of the 5,>,n-4-azido-3-iodo derivative 2 is thought to be the first example of a syn addition of iodine azide to an alkene.1,2 The formation of the syn-product is best explained by the twist strain theory,8 according to which the syn transition structure A is favored over the an/7-coplanar transition structure B.1... 

Azirines are also made by carbene addition to nitriles (89 — 90) and by thermal or photochemical (68JA2869) elimination of N2 from vinyl azides (e.g. 91 — 92). Vinyl azides are prepared by the Hassner reaction (68JOC2686, 71ACR9), where iodine azide is first added to an alkene and the resultant (3-iodoazide is dehydrohalogenated with base (Scheme 37) (86RTC456). 

The alkene pseudohalogen adducts (15) of Scheme 8 are also useful intermediates for aziridine synthesis. These adducts are discussed later in Sections 3.S.6.2-4. The iodine azide and bromine azide adducts may be reduced to aziridines with many reagents recent references report use of lidiium aluminum hydride - and dimethylamineborane. The iodine isocyanate aziridination continues to prove useful, as in Scheme Since the recent reviews, - the mechanism of the triphenylphosphine-based... 

Iodine azide, generally made in situ from ICl and NaNa in MeCN at 0 C, adds readily to alkenes by a similar heterolytic mechanism to INCO. Whereas the trans stereochemistry is generally well established,the regiochemistry of the adduct with 1-phenylcyclohexene has been queried recently it was originally formulated as the l-azido-2-iodo compound (Scheme 86), but base treatment was subsequently shown to yield what appeared to be 6-azido-l-phenylcyclohexene, which would have arisen from the l-iodo-2-azido isomer. However, it has very recently teen shown by 3(X) MHz NMR that the elimination product is in fact 3-azido-l-phenylcyclohexene, derived ultimately (Scheme 86) from the originally proposed l-azido-2-iodo- structure. 

Table 1. Selected / -lodo Azides by Ionic Addition of Iodine Azide to Alkenes...

Under a nitrogen atmosphere, even iodine azide undergoes addition to alkenes with a reversal of the regiochemistry, consistent with a radical pathway24,38 41. Furthermore, the solvent and the source of iodine azide affect the nature of the reagent and consequently the regio- and stereoselectivity of the addition14 16 42,43. 

Generally, iodine azide adds to an alkene by an ionic pathway, yielding a tram addition product however, in a few cases nitrile reagents compete successfully with azide ion in attacking the iodonium intermediate. Thus, ci-pinene was converted into tetrazole (125) in a one-pot reaction in near quantitative yield (Scheme 59).This type of process is far from general. 

Aziridines can be obtained from alkenes using iodine isocyanate or iodine azide. The product from the latter reaction can be converted into the aziridine via reduction, or into an azirine via elimination of hydrogen iodide and pyrolysis. " ... 

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