Formation of 1,4- and 1,5-regioisomers of triazolines in reactions of 2-ethoxyethyl azide with monosubstituted ethylenes

Thermal azide–alkene cycloaddition reactions: straightforward multi-gram access to Δ2-1,2,3-triazolines in deep eutectic solvents

“…The reaction of 1-azido-2-ethoxyethane with styrene has been reported to yield a mixture of regioisomeric triazolines after heating neat at 50°C for 30 days. 31 However, when we tried to reproduce this transformation, we obtained a mixture of 1,5-disubstituted triazoline and aziridine (49% and 35% 1 H NMR yield, respectively). This reaction could also be performed in DES, albeit low conversions were obtained after 16 h of stirring (Table 4, entry 5).…”