Subject azide synthesis

Alkyl azides are conveniently prepared from the reaction of alkali metal azides with an alkyl halide, tosylate, mesylate, nitrate ester or any other alkyl derivative containing a good leaving group. Reactions usually work well for primary and secondary alkyl substrates and are best conducted in polar aprotic solvents like DMF and DMSO. The synthesis and chemistry of azido compounds is the subject of a functional group series. ... 

Schkeryantz and Pearson (59) reported a total synthesis of ( )-crinane (298) using an intramolecular azide-alkene cycloaddition (Scheme 9.59). The allylic acetate 294 was first subjected to an Ireland-Claisen rearrangement followed by reduction to give alcohol 295, which was then converted into the azide 296 using Mitsunobu conditions. Intramolecular cycloaddition of the azide 296 in refluxing toluene followed by extrusion of nitrogen gave the imine 297 in quantitative yield. On reduction with sodium cyanoborohydride and subsequent reaction with... 

An extensive review of the chemistry of aliphatic and aromatic azides is given by Boyer and Canter [167] and Gray [168]. Organic azides are subject to various reactions such as the Bergmann degradation and the synthesis of peptides, the well known Curtius rearrangement, the Darapsky synthesis of a-aminoacids [169], for synthesis of triazoles [170], tetrazoles ( Schmidt reaction ) [169] and [171] etc. These reactions lie beyond the scope of the present book. 

The synthesis of novel azetidine derivatives remains the subject of intensive study. New procedures for the preparation of this class of compounds include, e.g., rearrangement of /3,7-aziridino-a-amino esters <2007OL4399>, copper-catalyzed multicomponent reactions of terminal alkynes, sulfonyl azides, and carbodiimides <20070L1585>, regioselective addition of 1,3-dicarbonyl dianions to iV-sulfonyl aldimines <2007T4779>, elaboration of a-amino acids <2007TL2471>, palladium-catalyzed iV-arylation of azetidines <2007S243> and... 

One of the best known reactions of 1-azirines is the acid/catalyzed hydrolysis to aminoketones. Since the Neber reaction also accomplishes this same synthetic end, this reaction may appear to have little practical value. This is not the situation because with the Neber reaction there is no control over the aminoketone that will be obtained from a given ketone. For example, when oxime (127) derived from benzyl methyl ketone (126) is subjected to the Neber reaction aminoketone 128 is obtained.59 The amino function is substituted for the most acidic a-hydrogen. The isomeric aminoketone (132) that could not be prepared by the Neber reaction can be formed by the hydrolysis of 1-azirine (131). The synthesis of this 1-azirine has been accomplished from allyl benzene (129) through vinyl azide (130) using iodine azide.22... 

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). 

The initial intent to cover the subject exhaustively had to be abandoned because of the overwhelming amount of relevant literature. The following reactions are not covered but are briefly discussed, with references to reviews and seminal papers, in the section on Comparison with Other Methods reactions of carbanions and enolates and their surrogates with nitrogen oxides, nitrite and nitrate esters, and nitroso and nitro compounds reactions of enolates with diazonium salts, including the Japp-Klingemann reaction the diazo transfer reaction except as it interferes with the synthesis of azides the animation of boranes and the Neber rearrangement. 

The total synthesis of dihydrolycorine (38), the sole hydrogenation product of lycorine (6 R1 + R2 = CH2, R3 = R4 = H) and an alkaloid in its own right, has been reported.27 Scheme 3 shows how treatment of the Diels-Alder adduct (33) with methanol gave a mixture of two half-esters which were directly subjected to Friedel-Crafts cyclization to give the indanone ester (34) and a rearrangement product. Attempted Schmidt ring expansion on (34) failed, but a prior reduction-oxidation sequence followed by treatment with sodium azide and hydrolysis produced the desired lactam (35) and an isomeric compound whose structure remains undetermined. Lactam (35) was readily converted into a chain-extended... 

Nuber and Hirsch, in the meantime, prepared bisaza[70]fulleroid 60 in a one-step synthesis from C70 with MEM azide in ODCB at 120°C. They observed that while 60 was formed preferentially, another bisadduct isomer [presumably the (l,6) (l,9)-isomer, according to modern lUPAC numbering] was formed as a byproduct. When this material was subjected to the reaction conditions that afforded aza[60]fullerenes from 8 (see Sect. 2.2.5), an analogous aza[70]fullerene dimer, most likely with the structure 61, and the methoxyethoxy derivative 62 could be isolated from the mixture in 10 and 15% yield, respectively (Fig. 26)... 

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