Triflyl azide, preparation

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). 

Scheme 2 Preparation and examples of aryl azides, (a) Three possible routes for the conversion of an aryl amine into its aryl azide (i) via diazotization [44], (ii) by the use of triflyl azide [45], and (iii) with sulfonyl azides 15 (R = imidazole [46] or R = benzotriazole [55]). (b) Examples of substituted aryl azides...

A versatile stereoselective synthesis of endo,exo-furofuranones was accomplished by R.C.D. Brown and coworkers. One of the key steps was a Rh(ll)-catalyzed C-H insertion reaction and the required diazo lactone was prepared via the Regitz diazo transfer reaction. The 2-acetyl substituted lactone substrate proved to be recalcitrant toward the deacylative diazo transfer under standard conditions. Eventually the authors decided to use the very reactive triflyl azide (TfNs), which was generated in situ under phase-transfer conditions to afford the desired a-diazo lactone. The C-H insertion product was then converted to (+)-methylxanthoxylol. 

The natural product (-)-oxetanocin is an unprecedented oxetanosyl-A/-glycoside that inhibits the in vitro replication of human immunodeficiency virus (HIV). In order to prepare multigram quantities of the compound, D.W. Norbeck et al. devised a short and efficient synthetic strategy. The cornerstone of the strategy was the Wolff rearrangement of a five-membered diazo ketone. The diazo transfer was achieved by first converting the ketone to an enamino ketone followed by treatment with triflyl azide. Upon irradiation with a 450 W Pyrex filtered Hanovia lamp, the isomeric oxetanes (a 3 = 2 1) were obtained in 36% yield. 

A. Titz, Z. Radic, O. Schwardt and B. Ernst, A safe and convenient method for the preparation of triflyl azide, and its use in diazo transfer reactions to... 

A series of imino-sugars with the imino group replacing the anomeric carbon atom have been prepared and tested as glycosidase inhibitors. Compound 45 was made from D-mannose via l,5-anhydro-4-C-hydroxymethyl-2,3-0-isopropyli-dene-L-ribofuranose. Compound 46 was also made from D-mannose via benzyl 2- C-benzyloxymethyl-2,3-isopropylidene-5-triflyl-a,P-D-lyxofuranose by successive treatment with azide, trifluoroacetic acid then hydrogenation-hydro-genolysis. ... 

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