Construction of five- and seven-membered rings facilitated by alkyne–azide functionality: access to quinoline fused triazolo-azepines†

The synthesis of novel quinoline-fused triazolo-azepine derivatives has been reported using an intramolecular 1,3-dipolar azide–alkyne cycloaddition strategy. This method possesses considerable potential to synthesize five- and seven-membered rings in high yields (65–87%) without the necessity of metal catalysts or additives. Additionally, this methodology was applicable to pyridine and tetralone based adducts to afford triazolo-azepine derivatives. This intriguing chemistry offers numerous advantages, including metal-free and additive-free processes, applicability to gram scale synthesis, high atom economy and easy access to a diverse library of potential pharmacological compounds in high yields.