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Non-explosive hydrazoic acid equivalent in many cycloaddition reactions: e.g. with alkynes to give 1,2,3-triazoles: Chem. Ber., 99, 2512 (1966), nitriles, catalyzed by Di-n-butyltin oxide, L14491, to give tetrazoles: J. Org. Chem., 58, 4139 (1993).•
In combination withSnCl4,?-D-ribofuranosyl acetates are converted to azides: Carbohydr. Res., 232, 359 (1992). Similarly, reaction with tert-halides in the presence of tin(IV) chloride gives tert-azides, which can be converted to iminophosphoranes by Staudinger reduction with Triethyl phosphite, L00339. Hydrolysis completes a one-pot sequence for the conversion of a tert-halide to the corresponding amine: Synthesis, 487 (1987).• Mitsunobu reaction, in the presence of DIAD, with 1,2- and 1,3-diols leads to regioselective, stereospecific azidation to give predominantly the 2- or 3-azido alcohol with inversion of configuration: J. Org. Chem., 64, 6049 (1999).
• In combination with triflic acid, is useful for the direct amination of aromatics. Aminodiazonium triflate is suggested as the active intermediate. Thus, benzene gives aniline in 95% yield and toluene gives a mixture of o- and p-toluidine: J. Org. Chem., 54, 1203 (1989). See also: Tetrahedron Lett., 32, 4321 (1991).
• For reviews, see: Chem. Soc. Rev., 7, 15 (1978); Synthesis, 861 (1980); Chem. Rev., 88, 351 (1988).
• A mild, convenient synthesis of alkyl azides involves SN2 reaction with the corresponding alkyl halide, phosphate or tosylate, promoted by TBAF: Synthesis, 376 (1995).
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Curtius reaction with acid halides gives isocyanates in one operation: Synth. Commun., 2, 227 (1972): Synthesis, 551 (1972); J. Org. Chem., 38, 2982 (1973). Similarly, pyridine-2,3-dicarboxylic anhydride is converted to 3-azaisatoic anhydride: Synthesis, 972 (1982):
