Generation of nitrenes

Thermolysis or photolysis of azides gives nitrenes with expulsion of nitrogen. This method is analogous to the formation of carbenes from diazo compounds. 

Alkyl nitrenes can also be obtained by the photolysis of isocyanates with the expulsion of carbon monoxide, a method analogous to carbene formation from ketenes. 

The reaction of N-benzenesulfonoxy carbamate (2.90) with a base results in the formation of carboalkoxynitrene with the elimination of benenesulfonate anion. 

Understanding the chemistry revolving around reactive intermediates, including radicals, diradicals, carbenes, and nitrenes, is necessary because they play a major 

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The types of azides that have been used for generation of nitrenes include alkyl,247 aryl,248 acyl,249 and sulfonyl250 derivatives. 

The direct photolysis of o-isocyanatobiphenyls 278 is yet another means for the generation of nitrene, which leads via cyclization to a carbazole. How-... 

A substantial 267-article review covers the theoretical treatment of nitrenes.72 Further reviews address the kinetics, spectroscopy, and computational chemistry of arylnitr-enes73 and the generation of nitrene species catalysed by transition metal complexes.74... 

In general, the reactive nitrenes can be generated by thermolytic or photolytic elimination of stable compounds from suitable precursors such as heterocycles, ylides, and azides. The most commonly used method for the generation of nitrenes is the thermolysis or photolysis of the corresponding... 

Common methods for generating nitrene intermediates are the photolysis and thermolysis of azides. Generation of nitrenes from acyl azides can only be effected photochemically thermolysis of an acyl azide gives the corresponding isocyanate. 

The majority of recent research in the photochemistry of azides and the generation of nitrenes has involved aryl rather than alkyl azides. Amongst the latter, however, is an interesting study of the photodissociation of methyl azide at wavelengths from 292 to 325 nm. The photodissociation dynamics of methyl azide are apparently complex, with the predominant pathway producing CH2=NH by concerted 1,2-H shift and N2 extrusion. Triplet methylnitrene (CH3N) was also observed by emission spectroscopy, but seems to arise by a minor, spin-forbidden pathway. 

Generation of nitrene [1, 482], Appel and Buchner4 reasoned that treatment of the reagent with base might liberate NH (nitrene, imene) and so they examined the reaction of the reagent with 1,4-butadiene in methanol in... 

Pyrolysis of the compounds 250 yields nitrene intermediates, which undergo a wide range of insertion reactions.502 529 W-Cyanopyrroles, which are obtained from the pyrolysis of tetrazolopyridines, also arise from nitrene intermediates via ring contraction.512,530 Mass spectral studies have indicated that the first step in the gas-phase pyrolysis of fused tetrazolopyridines and pyrimidines involves tautomerism to the azide with subsequent nitrene formation.523 Copper compounds have been found to catalyze the generation of nitrene intermediates from the compounds 250 and 244.531 The compounds 250 also undergo cycloaddition reactions through the azido form.511... 

Photoelimination of nitrogen is an efficient and mild method for the generation of nitrenes. Irradiation of the azide (106) results in formation of the -acylimine... 

Adamantane azide (106) behaves similarly (Scheme 10.26) after generation of nitrene 107, the main reaction consists of a 1,2-alkyl shift to form 4-azahomoadamant-4-ene (108) which can be isolated. As a side product, adamantane imine (109) is produced through... 

Scheme 6.6 Generation of nitrenes from azides and isocyanates.

Scheme 6.7 Generation of nitrenes from their relevant precursors.

Scheme 6.12 Photochemical generation of nitrenes from oxaziridines. 6.3.5...

Scheme 2 Photo induced generation of nitrenes and their addition to aikene doubie bonds.

Figure 302. Possible routes to the generation of nitrene-expanded ligands.

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