Azides with double bonds

The most popular type of photosensitive functionality is the aryl azide derivative. On photolysis, phenyl azide groups form short-lived nitrenes that react rapidly with the surrounding chemical environment (Gilchrist and Rees, 1969). Nitrenes can insert nonspecifically into chemical bonds of target molecules, including undergoing addition reactions with double bonds and insertion reactions into active hydrogen bonds at l"l C—H and N—H sites. Abundant evidence, however, indicates that the photolyzed... 

Accordingly, cycloaddition reactions can be carried out in solvents such as alkanes, cycloalkanes and acetonitrile. The insertion reaction into the O-H-bond of alcohols is, in every case, faster than the cycloaddition reaction. Furthermore, 100% production of isocyanate was observed upon irradiation of benzoyl azide in dichloromethane solution, however, nitrenes that can be trapped by compounds with double bonds are also formed in this solvent [21]. 

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-... 

Abstract Organic azides R-N3, albeit being energy-rich and very reactive, are useful intermediates in organic synthesis. The cycloaddition reaction of azides with double and triple bonds to yield heterocyclic structures - albeit being discovered many centuries ago - has been evolved into a powerful tool in organic synthesis, material sciences and life sciences, and are thus covered in this review. In particular, the recent development of catalytic and therefore mild reaction conditions has led to an enormous increase of systematic investigation and novel applications. 

The cycloaddition of azides with double and triple bonds to yield heterocycUc structures - albeit being discovered many centuries ago - has been evolved into a powerful tool in organic synthesis, material sciences and life sciences. 

That looks simple and direct don t it If safrole was used as the alkene one would get safrole-azide as product. Just one teensy little reduction away from MDA. Strike also found some azide papers that, with a little work, will get safrole-azide in a totally different way. Strike came across a lot of work where groups were using dinucleophilic addition to get an azide and a halogen added across a double bond. The azide would always go to the beta secondary carbon and the halogen to the primary carbon (just what one would want if safrole was the substrate). 

Addition on to the exocyclic C—C double bond of an alkylideneaziridine also occurs when this compound is allowed to react with organic azides (75JOC2045). The initially formed spirotriazolines (332) are converted into four-membered ring amidines (334) with extrusion of molecular nitrogen. In the case of phenyl azide, the amidine (334) is obtained alongside the triazoline (333). 

Diphenylthiirene 1-oxide reacts with hydroxylamine to give the oxime of benzyl phenyl ketone (79JA390). The reaction probably occurs by addition to the carbon-carbon double bond followed by loss of sulfur monoxide (Scheme 80). Dimethylamine adds to the double bond of 2,3-diphenylthiirene 1,1-dioxide with loss of sulfur dioxide (Scheme 81) (75JOC3189). Azide ion gives seven products, one of which involves cleavage of the carbon-carbon bond of an intermediate cycloadduct (Scheme 81) (80JOC2604). 

The C —C double bonds of 3-benzothiepins do not react with bromine (vide supra), nor with phenyl azide or diazoacetate however, one or two equivalents of diazomethane do add to 3-benzothiepins, e.g. 4, to yield crystals which melt with quantitative loss of nitrogen.65... 

Organoboranes react with a mixture of aqueous NH3 and NaOCl to produce primary amines. It is likely that the actual reagent is chloramine NH2CI. Chloramine itself,hydroxylamine-O-sulfonic acid in diglyme, and trimethyl-silyl azide " also give the reaction. Since the boranes can be prepared by the hydroboration of alkenes (15-16), this is an indirect method for the addition of NH3 to a double bond with anti-Markovnikov orientation. Secondary amines can be prepared by the treatment of alkyl- or aryldichloroboranes or dialkylchlorobor-anes with alkyl or aryl azides. 

Two azido groups can be added to double bonds by treatment with sodium azide and iodosobenzene in acetic acid." ... 

Aziridines can be prepared directly from double-bond compounds by photolysis or thermolysis of a mixture of the substrate and an azide. The reaction has been carried out with R = aryl, cyano, EtOOC, and RSO2, as well as other groups. The reaction can take place by at least two pathways. In one, the azide is converted to a nitrene, which adds to the double bond in a manner analogous to that of carbene addition (15-62). Reaction of NsONHC02Et/ CuO [Ns = A(/7-toluenesulfonyl-inimo)] and a conjugated ketone, for example, leads to the A-carboethoxy aziridine derivative.Calcium oxide has also been used to generate the nitrene.Other specialized reagents have also been used." ... 

The use of reductive alkylation conditions has been employed to access tricycles from the azide 353 <2002S242> (Equation 95). Hydroboration of the alkene double bond with dicyclohexylborane followed by reaction with the azide and subsequent elimination of nitrogen and cyclization gave the linear tricyclic diketopiperazine 354 and 355 as a mixture of diastereoisomers. 

The 1,3-dipolar cycloaddition reactions to unsaturated carbon-carbon bonds have been known for quite some time and have become an important part of strategies for organic synthesis of many compounds (Smith and March, 2007). The 1,3-dipolar compounds that participate in this reaction include many of those that can be drawn having charged resonance hybrid structures, such as azides, diazoalkanes, nitriles, azomethine ylides, and aziridines, among others. The heterocyclic ring structures formed as the result of this reaction typically are triazoline, triazole, or pyrrolidine derivatives. In all cases, the product is a 5-membered heterocycle that contains components of both reactants and occurs with a reduction in the total bond unsaturation. In addition, this type of cycloaddition reaction can be done using carbon-carbon double bonds or triple bonds (alkynes). 

Catalytic transfer hydrogenations for the reduction of carbon-carbon double bonds are illustrated in Scheme 4.18. Reductions of azide functionalities to amines with lipases suspended in organic media under microwave conditions have also been reported [206]. 

Acyl azides 268, derived from furan, thiophene and selenophene, add slowly at room temperature to the strained double bond of 5-methylenebicyclo[2.2.1]hept-2-ene. Two regioisomeric triazolines, 269 and 270, which form in the first step, are unstable and decompose with elimination of nitrogen to provide aziridine derivatives 271. Products 271 are isolated in good yield (73-85%). It is worthy to note that not only the terminal, unstrained double bond in the starting material, 5-methylenebicyclo[2.2.1]hept-2-ene, is unaffected, but also the typical dipolarophiles like esters of crotonic, propiolic and byt-2-ynoic acids do not react with azides 268 under these conditions (Scheme 39) <2002J(P1)1420>. 

This chapter has to do with reactions wherein the photochemical event is the breaking of a bond in a molecule. For a single bond this results in the formation of a pair of radicals or a diradical. For a double bond as in diazo compounds or in azides a carbene or a nitrene and nitrogen are formed. All these intermediates will then undergo further mono- or bi-molecular dark reactions or eventually recombine to ground state starting materials. 

Saxitoxin is a small tricyclic structure isolated from oceanic red tides it has attracted much interest for its peculiar structure and toxicity as a paralytic agent. The core structure that is related to a l-iminooctahydropyrrolo[l,2-f]-pyrimidine nucleus was prepared by rearrangement after oxidation of a double bond contained in a medium-size guanidine ring. This key intermediate in the synthesis was prepared from azide 376 with a judicious use of Mbs... 

There has been little recent work on the stannaimines, R2Sn=NR. The compound [(Me3Si)2N]2SnNAr (Ar = 2,6-diisopropylphenyl) can be obtained as dark red crystals that are stable below —30 °C, and have an Sn=N bond length of 203.0(3) pm. Above —30 °C, cyclization slowly occurs by intramolecular addition of CH of an isopropyl group to the double bond. It reacts with 2,6-diethylphenyl azide to give the stannatetraazole (Equation (194)).592... 

The cycloaddition of picryl azide with phenoxyallene took place at the C1-C2 double bond of the allene exclusively to give the triazoline intermediate 97 [89]. This intermediate underwent a facile Claisen rearrangement to yield cyclohexadienone 98, which rapidly tautomerized to phenol 99. 

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