Iodine azide addition

Ranganathan also reports iodine azide addition to camphene in MeCN at —10 °C to give two compounds 288 the minor component is (5 X = CHI) and the major component is probably (199 X = N3, Y = CH2I) and not the proposed unstable (199 X = I, Y = CH2N3). 2-Bornene yields (201) and the endo-azide (202) as major products, together with a small amount of the isomeric exo-azide.287... 

Table S. Products from Iodine azide addition to simple olefins...

The alternative explanation, that iodine azide additions to afi-un-saturated carbonyl compounds are of the Ad, type (equation 96) is. 

It is apparent, then, that precursors for terminal vinyl azides are obtained following iodine azide addition to olefins only when rather unusual steric or electronic factors are operating. A number of other reaction sequences have been investigated in the search for a general approach to the terminal compounds. The opening of a terminal epoxide by azide ion leads to an azidohydrin which can be readily dehydrated (equation 4). Unfortunately, this reaction sequence... 

Iodine azide, on the other hand, forms pure adducts with A -, A - and A -steroids by a mechanism analogous to that proposed for iodine isocyanate additions. Reduction of such adducts can lead to aziridines. However, most reducing agents effect elimination of the elements of iodine azide from the /mwj -diaxial adducts of the A - and A -olefins rather than reduction of the azide function to the iodo amine. Thus, this sequence appears to be of little value for the synthesis of A-, B- or C-ring aziridines. It is worthy to note that based on experience with nonsteroidal systems the application of electrophilic reducing agents such as diborane or lithium aluminum hydride-aluminum chloride may yet prove effective for the desired reduction. Lithium aluminum hydride accomplishes aziridine formation from the A -adducts, Le., 16 -azido-17a-iodoandrostanes (97) in a one-step reaction. The scope of this addition has been considerably enhanced by the recent... 

Iodine azide is a highly selective reagent addition to the 16-double bond of androsta-4,16-diene-3-ones is possible and some selectivity in addition to the 16-double bond of A -dienes has been observed.Hydroxy groups in the steroid should be protected, e.g., by acetylation, since in some instances oxidized side products are formed. 

Iodine azide, generated in situ from an excess of sodium azide and iodine monochloride in acetonitrile, adds to ethyl l//-azepine-l-carboxylate at the C4 — C5 and C2 —C3 positions to yield a 10 1 mixture of the rw-diazidodihydro-l//-azepines 1 and 2, respectively.278 The as stereochemistry of the products is thought to be the result of initial trans addition of the iodine azide followed by an SN2 azido-deiodination. The diazides were isolated and their stereochemistry determined by conversion to their bis-l,3-dipolar cycloadducts with dimethyl acetylene-dicarboxylate. 

Puacz et al. (1995) developed a catalytic method, based on the iodine-azide reaction, for the determination of hydrogen sulfide in human whole blood. The method involves the generation of hydrogen sulfide in an evolution-absorption apparatus. In addition, the method allows for the determination of sulfide in blood without interference from other sulfur compounds in blood. A detection limit of 4 g/dm3 and a percent recovery of 98-102% were achieved. Although the accuracy and precision of the catalytic method are comparable to those of the ion-selective electrode method, the catalytic method is simpler, faster, and would be advantageous in serial analysis. 

Finally, it is noteworthy that the addition of iodine azide to 3 leads mainly to the surprisingly stable tetrazido-substituted 2-tetrazene 74 (equation 76)96. The formation of 74 should start with the addition of IN3 to the double bonds of 3, giving four possible isomers. Under the applied conditions these compounds seem to be unstable. 

The addition of the pseudohalogen iodine azide (prepared from iodine monochloride and sodium azide in acetonitrile) to methyl 5,6-dideoxy-2,3-di-0-p-tolylsulfonyl-a -L-arabtno-hex-5-enofuranoside has also been achieved a crystalline /3-iodo azide was isolated, in 69% yield, that was stable in the dark, but became colored on exposure to light.130 Brimacombe and coworkers133 have reported the addition of iodine azide to 5,6-dideoxy-l,2-0-isopropylidene-o -D-xy/o-hex-5-enofuranose X-ray crystallographic analysis established that the product is 6-azido-5,6-dideoxy-5-iodo-l,2-0-isopropylidene-/3-L-idofuranose. 

A similar situation is found in 6-azido-5,6-dideoxy-5-iodo-1,2-0-isopropylidene-/3-L-idofuranose, prepared by the action of iodine azide (IN3 a pseudohalogen) on 5,6-dideoxy-l,2-0-isopropylidene-a-D-xylo-hex-5-enofuranose.53 The addition of iodine azide to the... 

Addition of iodine azide to 1-ethoxycarbonyl-l/f-azepine is regioselective and in the presence of sodium azide yields a 10 1 mixture of the c/s-4,5- and cis-2,3-diazides. The cis stereochemistry of the adducts is adduced to have arisen by initial trans addition of IN3, substitution of iodide by azide, and then conversion to the cis isomers via the azanor-caradiene valence tautomer (72JOC890). 

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... 

Alternatively, the addition of iodine azide under similar conditions to 9,10-dimethyltricy-clo[4.2.2.02,5]deca-3,7-diene produced the tetracyclic tetrazole 3, whose formation possibly involves initial reaction of the solvent acetonitrile with the azide ion.1 The addition proceeds via electrophilic attack of iodine azide with the formation of a three-membered iodonium ion intermediate backside opening of the intermediate results in the anti configuration of the tetrazole derivative (see Table 1). 

In systems without steric constraint, trans stereospecificity is observed. This aspect has been aptly demonstrated in the addition of iodine azide to 1-methylcyclobutene.10... 

The addition of iodine azide to double bonds gives p-iodo azides.674 The addition is stereospecific and anti, suggesting that the mechanism involves a cyclic iodonium ion interme-... 

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). 

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