Reactions of aryl azides with α-keto phosphorus ylides

A new conjugated addition of trialkyl phosphites and alkylidenephosphoranes to 3‐ω‐azideoacetyl coumarin synthesis of some 1,2,3,4‐triazaphospholes, triazoles, and azido‐coumarin derivatives

“…As depicted in , a 1,3‐dipolar addition of the azide 1 on the PC bond of the ylide 7b , 7c followed by elimination of TPPO from the cyclic intermediate 9 afforded N ‐1‐substituted‐5‐methyl (or 5‐phenyl)‐1,2,3‐triazoles 10a , 10b [19–23] . The formation of the triazoles from treating 1 with 7a , 7b adequately demonstrates the regiochemistry [23] of the reaction that leads to the exclusive formation of 1,5‐ instead of 1,4‐disubstituted triazoles. Furthermore, the formation of 10b , 11a through either a two step addition, via the intermediate 9 , or a concerted cycloaddition, via the transition state 9A , is consistent with the observed result.…”

Reaction of 2,6-Bis(4-azidobenzylidene)-4-methyl-cyclohexanone with Organophosphorus Reagents. Synthesis of Some Benzylidene-1, 2, 3-triazole Derivatives

“…A possible explanation of the reaction course of azidobenzylidene (4) with phosphorus ylides (3a-d) is shown in Scheme 7. The reaction can be visualized as 1,3-dipolar cycloaddition of the azide (4) to C=C bond of the ylides (3a-d) (enolate form) occurred in the first step of the reaction followed by loss of OPPh 3 from the cyclic intermediate to give N-1 substituted-1,2,3-triazoles (7a-d) (25,26) . Previously it has been reported that triazoles can be easily obtained through microwave irradiation (27) .…”

Heterocyclic Chemistry Using Microwave‐Assisted Approaches

“…One reported example involves the reaction of ␣-acylphosphonium ylides with aryl azides to afford 1-aryl-5-substituted 1,2,3-triazoles (Scheme 3.18). This reaction was initially reported to take place in refluxing benzene and required several days of reaction time 30 . The same reaction was performed in a domestic microwave instrument using silica gel as the support.…”