Phosphorus ylides reaction with azides

Ykman, P., L Abbe, G. and Smets, G., Reactions of aryl azides with a-keto phosphorus ylides, Tetrahedron, 1971, 27, 845-849. 

The preparation of N-acyl-1,2,3-triazoles by reaction of N-trimethylsilyl derivatives with acetyl chloride has been reported by Birkofer and Wegner (Eq. 1). In a later paper they showed that the 1-N-product (5.1-1) is obtained at low temperature (15°), and the 2-N-product (5.1-2) at high temperature (120°). The yields are generally high (ca. 90%), and the isomer ratio for an unsymmetrical case was determined (Eq. 2). Zbiral and his collaborators have added acetyl azide to a-keto phosphorus ylides and have obtained generally good yields of N-acetyl-1,2,3-triazoles (Eq. 3). The isomer ratio for unsymmetrical products (5.1-3) was not determined. 

Several D-ribofuranosyl [113] and L-arabinofuranosyl 1,2,3-triazole derivatives [114] such as 119 have been prepared by cycloaddition of the corresponding glycosyl azide to 2-ethoxycarbonyl-2-oxoethylidene-triphenylphos-phorane, followed by reaction with methanolic ammonia or primary or secondary amines (Scheme 29). Some of prepared nucleosides proved to be potent inhibitors of HIV-1 replication. Phosphorus ylides containing an a-oxo group in the chain behave in a similar way as activated acetylenes with electron-donating groups [108[. Presimiably the azide adds to the enolate form of the ylide, followed by elimination of PhsPO [108]. 

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