A transition-metal-free azide–alkyne cycloaddition/oxetane ring opening cascade reaction for the construction of hydroxymethyl decorated triazole-fused piperazin-2-ones and [1,4]diazepin-4-ones†

Abstract

A versatile synthesis of functionalized triazole-fused piperazin-2-one and [1,4]diazepin-4-one scaffolds via a cascade azide–alkyne cycloaddition/oxetane ring opening reaction is reported. This approach features broad functional group compatibility and high atom economy and avoids the use of transition-metal catalysts. Several transformations of the triazole-fused piperazin-2-one product are carried out to showcase the synthetic potential of this method for the construction of bioactive compounds.