Olefins diazidation

The electrophilic nature of alkoxy radicals is evident from their reactions with olefins which are conjugated to electron-withdrawing substituents With such substrates, both a diazide and the... 

Direct introduction of HN3, or its equivalents, onto olefins constitutes an efficient and straightforward approach. Unfortunately, the most efficient reactions are multi-step sequences, such as epoxidation followed by opening with azide ions or hydroboration followed by iodination and snbstitution. Several one-step methods, such as halo-azidation, diazidation, seleno-azidation, nitrato-azidation, ° formation of a-azido ketones," and carboazidation, have also been reported, bnt the conceptually simplest reaction, the hydroazidation reaction, has been much less developed (Figure 4.1). 

Hypervalent iodine compounds represent a nsefiil source of azidyl radicals. For instance, a mixture of iodosyl benzene (PhIO), acetic acid, and sodium azide is employed for the diazidation of several olefins. A carbocationic mechanism has been proposed bnt azidyl radicals are likely responsible for the observed reactivity. ... 

Nocquet-Thibault S, Rayar A, Retailleau P, Cariou K, Dodd RH (2015) Iodine(in)-mediated diazidation and azido-oxyamination of enamides. (Them Eur J 21(40) 14205-14210 Yuan YA, Lu DF, Chen YR, Xu H (2016) Iron-catalyzed direct diazidation for a broad range of olefins. Angew Chem Int Ed 55(2) 534-538... 

The addition of HN3 to nonactivated alkenes with formation of the saturated azides requires drastic conditions and a catalyst. Olefinic double bonds activated by conjugated, electron-withdrawing groups like -CN, -NO2, or -C(0)R react easily [8, 9]. The photolysis [10] and the pyrolysis [7] of HN3 with alkenes yields nitriles, N2, and decomposition products. The reaction of HN3 with alkines usually leads to 1,2,3-triazoles. Single or double addition with formation of vinyl azides or saturated diazides are rare [8, 9]. Arenes and HN3 form aniline derivatives directly and efficiently in the presence of trifluoroacetic acid and the strongly acidic trifluoromethanesulfonic acid [11]. The yield is frequently low in the presence ofH2S04[1]. 

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