Reaction with iodine azide

Ring-opening of -pinene with iodine," and of a-pinene with a zinc-copper couple have been mentioned addition of acrolein and methyl acrylate to -pinene may also result in some ring-opened products,and so do the reactions with iodine azide, aldehydes in the presence of light, and ketones in the presence of t-butyl peroxide. Of particular interest in this respect is a paper by Julia et al., who describe the production of cis- and trans-carveols (118) from a-pinene, and perilla alcohol (388) from -pinene with retention of configuration, using benzoyl peroxide in the presence of cupric salts. ... 

Aziridines are formed from alkenes in a number of multistep processes involving initial reaction with iodine azide, iodine isocyanate or NN-dichlorourethane ... 

This reaction is catalyzed by the presence of divalent sulfur — e.g. sulfur ions, substances with S-S links, thioethers, thiazoles. If such substances are present in a chromatogram zone then the iodine applied with the reagent is consumed by reaction with sodium azide according to the above reaction. It is no longer available for the for-... 

Significant amounts of the bicyclo[3.3.1]nonane adduct and of the octahydropental-enes were isolated also from the reaction of 3 with preformed iodine acetate and iodine acetate thallium (equation 75)94 whereas only the monocyclic 1,2-adducts were obtained from treatment of 3 with iodine azide, iodine isocyanate or iodine nitrate95. The different propensity to give transannular products with these latter reagents has been related to the different positive charge density on carbons in the corresponding iodonium ion intermediates. 

Reaction of iodine azide with olefins followed by reduction leads to a stereospecific synthesis of aziridines [59]. 

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... 

Imino thioethers,2 The reagent, prepared in situ, converts the dimethyl thioketal of a cyclic ketone (2) into the imino thioether 3 in high yield. The reaction can also he carried out with azidotrimethylsilane (1 equivalent), stannic chloride (1 equivalent), and iodine (10 mole %). but yields arc lower. This reaction was examined because of the reaction of thiokctals with iodine azide (this volume). 

Amides lactams. Dimethyl thioketals of cyclic or acyclic ketones react with iodine azide to form an a-azido sulfide in 75-95% yield. The product rearranges to an amide or a lactam in high yield in the presence of trifluoroacctic acid. This sequence is an attractive alternative to the Beckmann rearrangement or Schmidt reaction. 

The reaction of cL-2-pentcne with iodine azide (IN3) in dichloromethane gives (2S,3S)-3-azido-2-iodopentane and (2 A , 3 A )-3-azido-2-iodopentane but not any other diastereomers. What is the stereochemistry of the addition and give a curved-arrow mechanism to account for it. 

Normally, iodanes with one or two azido groups attached to iodine(III) are very labile. Two cyclic iodanes, however, l-azido-l,2-benziodazol-3(lH)-one and its 2-acetoxy derivative, are stable. They are prepared from the corresponding 1-acetoxybenziodazoles by reaction with trimethylsilyl azide (Scheme 25) [76,77]. 

March82 has summerized the addition reactions of iodine isocyanate (IN=C=0) to C=C functions which were reported in the period 1963-1983. These reactions are similar to those with iodine azide described above. With IN=C=0, p-iodo isocyanates are formed (equation 55). As is the case with IN3, the addition is stereospecific and anti. The... 

Azirines are also made by carbene addition to nitriles (121 122) and by thermal or photochemical elimination of N2 from vinyl azides (123 124) . Vinyl azides are prepared by the Hassner reaction, where iodine azide is first added to an alkene and the resultant -iodoazide is dehydrohalogenated with a base this approach is illustrated by the preparation of haloazirines 125 (Scheme 66) <2001T6203>. 

The reaction of iodine azide in acetonitrile with cyclic conjugated dienes and polyenes afforded cis-1,2- or cis- 1,4-diazides80 81 in 80-90% yield, via SN2 reaction of the azide ion with the intermediate trans-/)-iodo azides (Section 1.2.2.2). These diazides were not purified, due to their explosive nature, and their stereochemistry was deduced from the H-NMR spectrum of the cycloadducts obtained with dimethyl acetylenedicarboxylate80,81. Instead, the addition of iodine azide to. V-acyl and 7V-sulfonylindole82-83 and benzofuran83 gave mixtures of trans- and cis-2,3-diazides. 

The reaction of iodine azide with haloalkenes 839 followed by elimination of hydrogen halide by potassium fetf-butoxide gives the corresponding halovinyl azides 840, which can be converted into haloazirines 841 by photolysis at —40 C (Scheme 209) <2001T6203>. 

However, the products of the reaction of medium sized cyclic olefins, such as cyclooctene, with iodine azide did decompose to give the vinyl azides... 

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