From sulfonyl azides

Diazocarbonyl compounds can be prepared on insoluble supports by diazo group transfer with sulfonyl azides or by diazotization of primary amines. Diazo group transfer from sulfonyl azides to 1,3-dicarbonyl compounds proceeds on cross-linked polystyrene as smoothly as in solution (Table 10.19). When 3-keto esters or amides are... 

The direct diazo transfer from sulfonyl azides to methyl ketones is usually not a practicable process, with the exception of the a-diazotization of ketones with 2,4,6-triisopropylbenzenesulfonyl azide under phase-transfer conditions. However, diazomethyl ketones amenable to the Arndt-Eistert reaction can be easily prepared in two steps by a formylation-deformylation diazo-transfer sequence (Regitz procedure ). A related practical method advantageously applies the detrifluoroacetylation of a-trifluoroacetyl ketones tScheme 3 a). The preparation of 2-diazo-1,3-dicarbonyl compounds is commonly best performed with p-toluenesulfonyl azide (TsNg) as the diazo-transfer reagent tScheme 3.9h). > An issue... 

Several important a-diazo ketones cannot be prepared via this approach however due to their base-sensitive nature. Danheiser and coworkers reported a detrifluoroacetylative diazo transfer strategy to combat this shortcoming. Deprotonation of substrate 52, followed by a trifluoroethyl trifluoroacetate (TFEA) quench furnished the trifluoroacetylated product. This undergoes facile detrifluoroacetylative diazo transfer from sulfonyl azide 54, to yield diazo ketone 53. In general they found TFEA to be superior to other trifluoroacetylating agents. 

A three-component reaction for the synthesis of functionalized benzimidazoles from terminal alkynes, o-aminoanilines, and / -tolylsulfonyl azide is developed by Wang and coworkers (Scheme 8.52). The C(sp)-H bond of alkyne was activated in this reaction via Cul-catalyzed azide-alkyne cycloaddtion (CuAAC) reaction which could lead to the formation of a ketenimine intermediate by the release of N2- The benzimidazoles could be obtained by intramolecular nucleophilic addition and subsequent elimination of amide intermediate with 2% H2SO4 under reflux conditions [91]. They also developed another protocol for the synthesis of substituted benzimidazole derivatives via a sequential three-component cascade reaction from sulfonyl azides, alkynes, and 2-bromoanilines using Cul as catalyst. Similarly, the C-H bond of alkyne was activated at the process of copper-catalyzed azide-alkyne cycloaddtion (CuAAC) reaction [92]. 

SCHEME 5.56 Cu(I)-catalyzed formation of the ketenimine intermediate from sulfonyl azide and terminal aUcyne. 

Mg or Ca in MeOH, " baker s yeast, Sm/l2, LiMe2NBH3, and tin complexes prepared from SnCl2 or Sn(SR)2. This reaction, combined with RX —+ RN3 (10-65), is an important way of converting alkyl halides RX to primary amines RNH2 in some cases the two procedures have been combined into one laboratory step. Sulfonyl azides (RSO2N3) have been reduced to sulfonamides (RSO2NH2) by irradiation in isopropyl alcohol and with NaH. ... 

The impure compound, present as a majority in the distillation residue from preparation of 1-diazoindene, will explode if the bath temperature exceeds 120°C [1], A polymer-bound sulfonyl azide reagent has been described as safer in use than the title compound [2], Distillation of the azide at 130-132 C/ 0.5 mbar from an oil bath at 145°C led to darkening, then violent explosion of the 30-40% residue [3],... 

Decomposition of sulfonyl azides was shown to be catalyzed by copper in 1967 (72, 73). In the presence of alkenes, the reaction provides both aziridines and the C-H insertion products, albeit in low yields (73). In 1991, Evans et al. (74, 75) illustrated that both Cu(I) and Cu(II) salts were effective catalysts for nitrenoid transfer from [A-(/Moluenesulfonyl)imino]phenyliodinane (PhI=NTs) to a variety of acceptor alkenes. In the absence of ancillary ligands, reactions proceed best in polar aprotic solvents such as acetonitrile. Similar results are observed using both Cu(MeCN)4C104 and Cu(acac)2 as precatalysts, Eq. 53. 

A reaction known as diazo group transfer produces diazo barbituric acid from barbituric acid and p-toluene sulfonyl azide. Additional barbituric acid affords azo barbituric acid [7]. Subsequent complexation with a nickel (II) salt yields a greenish yellow pigment. 

Closure to the triazoline certainly occurs in many systems, since products are isolated which can only have been formed by this route. Occasionally these products include w-triazoles for example, 4-phenyl-triazole is isolated in moderate yield from the reaction of the aldehydes (3) with toluene-p-sulfonyl azide (Scheme 9). ... 

Triazoles have also been obtained when the carbon atom adjacent to the activated methylene group carries a nitrogen function (i.e., amides, nitriles, amidines, and imines - ). In many of these cases it is impossible to decide, without N-labeling experiments, whether the third nitrogen of the triazole ring is derived from the toluene-p-sulfonyl azide or from the activated methylene compound. With amides, amidines, and nitriles, the first possibility seems more reasonable, but with imines, the third nitrogen is that of the imino group (Scheme... 

The HC1 generated in this reaction destroys one equivalent of diazomethane. This can be avoided by including a base, such as triethylamine, to neutralize the acid.74 Cyclic z-diazoketones, which are not available from acyl chlorides, can be prepared by reaction of an enolate equivalent with a sulfonyl azide. This reaction is called diazo transfer 5 Various arenesulfonyl azides76 and methanesulfonyl azide77 are used most frequently. Several types of compounds can act as the carbon nucleophile. These include the anion of the hydroxymethylene derivative of the ketone78 or the dialkylaminomethylene derivative of... 

A mixture of sulfonyl-azafulleroid 168 and sulfonylaziridino-fullerene 169 was obtained by reaction of sulfonyl azide with CgQ in o-dichlorobenzene at 160 °C (Scheme 4.30) [173]. The ratio of the two products depends on the substituent of the sulfonyl group. In all cases the aziridino fullerene can be obtained from the azafulleroids by irradiation. 

Numerous methods to prepare individual classes of aliphatic diazo compounds have been extensively developed. The major strategies for their synthesis involve the alkaline cleavage of N-alkyl-N-nitroso-ureas, -carboxamides and -sulfonamides, dehydrogenation of hydrazones, as well as diazo group transfer from sulfonyl and related azides to active methylene compounds, and electrophilic diazoalkane substitution reactions. These synthetic methods have been comprehensively reviewed (15,16). Useful information on the preparation of selected diazo compounds can be found elsewhere (6,17). 

Phenoxysulfonyl azide. This novel azidosulfate is prepared in two steps from phenol (equation 1), preferably under homogeneous conditions. Sulfonyl azides arc reduced lo sullamaics, Ar0S03NH2, which undergo cycloaddition with alkenes to formn/.iridiiies.- ... 

Sulfonyl azides react with pyridine to give pyridine 1-sulfonylimides (e.g. 367). However, the analogous reaction with 2,4,6-trimethylpyridine gives some 3-(phenylsulfonylamino) derivative together with the 1-sulfonylimide. Nitrenes derived from photolysis of acyl azides also add to the nitrogen atom to form the corresponding pyridine A-imines (74AHC(17)220). 

Kwart and Kahn have found that benzenesulfonyl azide forms a complex with freshly reduced copper powder.189 190 This copper azide complex decomposes at a lower temperature than the pure sulfonyl azide. In refluxing methanol, benzene-sulfonamide (27) is isolated as the major product. In the presence of dimethyl sulfoxide, N-benzenesulfonyldimethyl-sulfoximine (28) is obtained in almost quantitative yield. In cyclohexene solution benzenesulfonamide (29), N-benzenesul-fonyl-7-azabicyclo[4.1.0]heptane (30), and 1-cyclohexenylben-zenesulfonamide (31) are isolated as the main reaction products. According to the authors, Schemes VII and VIII represent an acceptable interpretation of the experimental data.189 190 In pure alcohol, the decomposition should occur by two competitive reactions (Scheme VII) producing benzenesulfonamide together with a ketone and oxidized copper. These last two products have indeed been observed in the reaction mixture. In the presence of DMSO, it seems that a copper-nitrene intermediate is formed which is trapped by DMSO. In cyclohexene solution, the authors have observed that the aziridine (30) disappears from the product composition when DMSO is added. The yield of enamine 31, however, is... 

The reactions of vinyl ethers with sulfonyl azides have been described by several authors.260-273-275 From dihydropyran the arylsulfonimines of 5-valerolactone (87) are obtained. These compounds rearrange at ca. 180° into N-arylsulfonyl-2-piperidones (88) (Chapman rearrangement).276... 

With a range of methods available for the formation of 1,3-dicarbonyl compounds, the dicarbonyl diazomethanes can be readily prepared via a simple diazo transfer reaction with sulfonyl azide. This has made a vast array of dicarbonyl diazomethanes available, which enhances the versatility in organic synthesis. A selection of examples from recent literature to illustrate the versatility of the cyclopropanation using dicarbonyl diazomethane in the construction of natural products as well as other biologically active compounds is described below. 

The reaction of dienamines and sulfonyl azides provides a method for the synthesis of vinyldiazomethanes.233,431 Likewise, the pyrolysis of a fluo-rinated 1-benzyltriazoline over a nickel surface yields difluorodiazometh-ane.145 The formation of diazo compounds from the reaction of azides with alkylidene phosphoranes apparently originates from an intermediate triazoline compound (Scheme 145)408,411 412,415,441... 

N-Methylindole acts like an enamine with sulfonyl azides and gives a diazoimino compound.443-445 So does dihydropyridine but only in the presence of 5% lithium hydroxide (Scheme 147).242 A triazole is postulated to be formed from the triazoline followed by a ring opening oxidation of diazoamino compounds to triazoles has been known to proceed via a diazoimino compound in equilibrium with the triazole (Scheme 1 19).285-3"-400... 

Amidines are also formed from less stable 1-hetaryl-220 and l-styryl-5-aminotriazolines.222,492,493 Thermolysis of the latter provides a method of synthesis of novel l-amino-2-azabutadienes (Scheme 176)492,493 Whereas cyanogen azide addition to dihydropyridines leads to bicycloazir-idines,241-243 addition of ethyl azidoformate yields the corresponding amidine 494 Likewise, indoles (103) react with picryl and sulfonyl azides to give... 

Aminoamidines (105) are also formed from the reaction of picryl and sulfonyl azides with indoles (103) when R1, R2, and R3 are all alkyl groups or a... 

Aryl azides (such as 13) can be easily prepared from their corresponding amines (12) in one or two steps. Three examples are given in Scheme 2a. The most common method is the diazotization of the amine with sodium nitrite under acidic conditions (giving diazonium species 14), followed by addition of sodium azide in an aqueous medium (route i in Scheme 2a) [44], In 2003, the synthetic method was improved by application of triflyl azide (TfN3), which allowed a one-step conversion and gave improved yields (route ii in Scheme 2a) [45]. Recently, the development of sulfonyl azides 15 (with R = imidazole [46] or R = benzotriazole [47]) was reported these proved to be more stable reagents and allowed a conversion under mild conditions (route iii in Scheme 2a). 

Iminocoumarins are formed in high yield from the Cu-catalysed multicomponent reaction of salicylaldehyde, alkynes and sulfonyl azides. It is considered that an initially formed ketimine reacts with the salicylaldehyde hydroxy function and an intramolecular nucleophilic addition to the aldehyde moiety completes the sequence (Scheme 29) <06OL4517>. 

A sample of the hexane layer from the reaction mixture is diluted 10 fold with hexane, spotted and developed as described in Note 4. Visualization by UV light shows Rf = 0.3 for sulfonyl azides. 

The assay for sulfonyl azides is adapted from the method of Siewinski, et al.3 The azide content of the hexane solution was assayed as follows to determine the contained yield ... 

---