Cyclopropyl azides

The reaction of azide ions with aliphatic diazo compounds was investigated by Kirmse et al. (1979 for a discussion see Zollinger, 1995, Sec. 6.1). Here we mention only that cyclopropanediazonium ions react similarly to the aromatic diazonium ions, i.e., by TV-coupling to 1-cyclopropylpentazene and dediazoniation to cyclopropyl azide. In about 60% of the 1-cyclopropylpentazene the cyclopropyl azide is formed directly by dediazoniation of the original diazonio group, while in 40% the route is via the cyclopropylpentazole. 

Thermal ring expansion of cyclopropyl azides provides a general route (95 — 96) to alkyl- and aryl-azetines (79CB3914). 

CYCLOPROPYL AZIDES Mercuric azide. CYCLOPROPYLCARBINYL COMPOUNDS 3-Butenyitri-n-butyltin. CYCLOPROPYL KETONES Potassium t-buloxide. Sodium ethoxide. Sulfuric add. 1,3-DEHYDROADAMANTANES n-Butyi-lithium. 

In contrast, the photolysis of these azides at 350 nm leads only to the corresponding nitriles and olefins in yields of 90 l-(Alkylthio)cyclopropyl azides (164), readily accessible from the corresponding chlorides and bromides, are smoothly decomposed at ITC with nitrogen evolution. The main process is a ring enlargement to 2-(alkylthio)azetines (165), accompanied by cleavage to an alkyl thiocyanate and an alkene (equation 114). ... 

Reaction of a cyclopropane with diazomethane or an azide generated cyclopropanes containing an azo function " a similar cycloaddition was reported for a nitri-limine. Cycloaddition of an ethandiylidene biscyclopropane and triazolinedione led to a hydrazine derivative Reactions of these types forming azo- or hydrazinocyclopro-panes are not subject of this review however, they could be of interest for aminocyclop-ropane synthesis by functional group interconversion (for the cycloaddition of cyclopropyl azide with a carbon-carbon double bond see Section II.E.3, equation 101). 

A special aminocyclopropane (409) could be prepared by cycloaddition of azide (406) with compound 407 (equation 101) (see also Section II.A.2.b for an easy preparation of cyclopropyl azides see Ref. 218). 

N3 as a nucleophile gave mainly cyclopropyl azides to a greater extent 115,117,138,139,604 consequence of an azo coupling leading to a pentazene and... 

Cyclopropanes, 101, 267 Cyclopropanone ketals, 315-316 Cyclopropene, 113 Cyclopropenone, 519 Cyclopropenones, 27, 399 Cyclopropylacetylene, 401 Cyclopropyl azides, 323 Cyclopropylcarbinyl compounds, 53 Cyclopropyldiphenylsulfonium fluoroborate, 211,213-214... 

Cyclopropyl azides.2 Mercuric azide adds syn to cyclopropenes (1) to give cis-2-azidocyclopropylmercuric azide salt (2) in fair yield. Reductive demercuration with NaBH4 gives cyclopropyl azides (3) in moderate yield. 

N-N bond formation also occurs when cyclopropylamines are converted to the corresponding cyclopropyl azides by treatment with methyllithium or methylmagnesium bromide ° followed by tosyl azide. The yield can be as high as 50%, but is usually significantly lower ° when methylmagnesium bromide is used. 

Cyclopropyl-l-nitrosourea and carbamate derivatives afford the corresponding cyclopropyl azides on treatment with lithium azide in methanol however, the yields are low (< 40%). 1-Cyclopropyl-l-nitrosourea reacted with potassium /er/-butoxide in tetrahydrofuran at low temperature to give the corresponding potassium diazotate. ... 

For example a- and jS- A -labeled cyclopropyl azides 12a and 12b, respectively, were obtained in addition to unlabeled allyl azides 13, when A -labeled 1-cyclopropyl-1-nitrosoureas 9a and 9 b, respectively, were deaminated in a methanolic solution of unlabeled lithium azide, showing the intermediacy of coupling product cyclopropylpentazene 11 (and the corresponding pentazol). ... 

Cyclopropyl azides undergo thermal ring expansion to azetines in good yields, but photolysis leads only to cleavage into olefin, nitrogen, and a nitrile (Eq. 126).454 ... 

The cyclopropyl azide (140) is smoothly decomposed at 70°C to give a nitrene that can interact not only with the three-membered ring but also with the double bond, leading to the A -thiazoline (141) and the thiazolidine... 

A number of 1-azetines have been obtained from thermolysis of cyclopropyl azides, nitriles and alkenes being side products. The cyclopropyl azides were obtained by transfer of a diazo-group from tosyl azide to cyclopropylamine anions or from carbene/carbenoid additions to vinyl azides. The azetine (1) was oxidized... 

Thermal or photochemical decomposition of cyclopropyl azides may give rise to 1-azetines and/or stereospecific fragmentation to olefin plus nitrile. In contrast to the photochemical reaction, substituents have a pronounced effect on the thermal reaction pathway. In general, substitution in the 2-position of the cyclopropyl azide... 

Azetines from cyclopropyl azides Regiospecific ring expansion... 

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