Methanesulfonyl azide

Pyrolysis or photolysis of methanesulfonyl azide in 2-methyl butane (RH) produces formal C H insertion adducts attributed to reactions of the thermally generated nitrene. The selectivity of this nitrene for 3°/2°/l° C—H bonds was 6/2.3/1.0 Sulfonyinitrenes, like acylnitrenes, insert into the OH bonds of alcohols. 

Compounds containing a CH2 bonded to two Z groups (as defined on p. 464) can be converted to diazo compounds on treatment with tosyl azide in the presence of a base,164 The use of phase transfer catalysis increases the convenience of the method.165 p-Dodecylbenzenesul-fonyl azide,166 methanesulfonyl azide,167 and p-acetamidobenzenesulfonyl azide168 also give the reaction. The reaction, which is called the diazo transfer reaction, can also be applied to other reactive positions, e.g., the 5 position of cyclopentadiene.169 The mechanism is probably as follows ... 

The diazo transfer reaction with sulfonyl azides has been extensively used for the preparation of diazo compounds with two electron-withdrawing groups (equation 1 ).28 Toluenesulfonyl azide (13a)29 is the standard reagent used, but due to problems of safety and ease of product separation, several alternative reagents have been developed recently. n-DodecylbenzenesuIfonyl azide (13b)30 is very effective for the preparation of crystalline diazo compounds, while p-acetamidobenzenesulfonyl azide (13c)31 or naph-thalenesulfonyl azide (13d)30 are particularly useful with fairly nonpolar compounds. Other useful reagents are methanesulfonyl azide (13e)32 and p-carboxybenzenesulfonyl azide (13f).33... 

Methaneperoxoic acid, see Peroxyformic acid, 0419 Methanesulfinyl chloride, 0434 Methanesulfonic acid, 0486 Methanesulfonyl azide, 0464... 

The submitters originally used methanesulfonyl azide,4 but the Board of Editors of Organic Syntheses requested substitution of the much less shock sensitive reagent 4-dodecylbenzenesulfonyl azide. The use of methanesulfonyl azide has previously been recommended,43 since excess reagent as well as certain formamide by-products can be easily separated from the desired diazo ketone product during workup by extraction into dilute aqueous base. 

To prepare an a-diazo ester from the ester (129) itself, formylation is effective. Alternatively, it has been reported that trifluoroacetylation of an ester proceeds smoothly (equation 53).The trifluoro-methylacetoacetate (130) would be expected to react directly with methanesulfonyl azide and sodium hydride to give the a-diazo ester. 

Intramolecular C—H insertion, on the other hand, is already a practical alternative for the constmction of cyclobutanols, P-lactams - and of cyclopentane-containing targets. With regard to the latter, diazo transfer can be effected on a large scale with the inexpensive methanesulfonyl azide. The rhodium carboxylate catalysts are effective at very low concentration (<1 mol %) and can easily be recovered from the reaction mixture, if desired. ... 

The electron-deficient sulfonyl nitrene (88) can insert into electron-rich carbon-hydrogen bonds, abstract hydrogen atoms, and add to double bonds and aromatic rings. These reactions may be initiated by acids, heat, light and transition metals. The reactions are illustrated by heating methanesulfonyl azide (89) with bezene (23) (Scheme 59). Here, the electrophilic sulfonyl nitrene (90) adds to the electron-rich aromatic double bond, but the kinetically favoured azepine(91) rearranges to give the thermodynamically favoured N-phenyl sulfonamide (92) (Scheme 59). 

Formylation followed by the deformylation diazo transfer reaction of 4-chromanone (65) produces 2-diazochromanone(66) in overall yield of 55-60%.24 Diazo transfer from methanesulfonyl azide to dimethylbenzosuberone (67) is achieved via deformylation.25... 

Difficulties have been reported in the chromatographic separation of the desired product from excess 4-toluenesulfonyl azide and 4-toluenesulfonamide (Doyle et al., 1985 Hudlicky et al., 1985). Taber et al. (1986, 1988) found that methanesulfonyl azide (mesyl azide) is generally a superior reagent for diazo transfer. ... 

The advantage of methanesulfonyl azide (mesyl azide) is that it is easily separated from the desired product by washing the organic phase (CH3CN or ether) with 1097o aqueous NaOH solution. Other transfer reagents are either more expensive or show similar disadvantages to those of 4-toluenesulfonyl azide (see Taber et al., 1986, references 5 and 6). Since 1985, Taber (1989) prefers mesyl azide to 4-toluenesulfonyl azide in all diazo transfers. 

The results discussed above clearly demonstrated that the cleavage of the dihydrotriazole ring to diazoalkane products following Scheme 2-67 is facilitated most by 4-toluenesulfonyl azide, although, in some cases, diazoalkanes can also be obtained with other aryl azides. Unfortunately, no study has been conducted comparing reactivity, products, and the yields of reactions with methanesulfonyl azide. This transfer reagent was recommended by Taber et al. (1986, see Sect. 2.6) as a superior reagent to 4-toluenesulfonyl azide. 

A soln. of methanesulfonyl azide in isopropanol-water irradiated 80 min. in a slow Ng-stream with a high-pressure Hg-arc lamp until gas-evolution ceases -> methane-sulfonamide. Y 99.8%. F. e., also in the presence of benzophenone as sensitizer, s. M. T. Reagan and A. Nickon, Am. Soc. 90, 4096 (1968). 

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