Huisgen [2+3]-Cycloaddition Route to Triazolopyrazinones

Significance

Presented is the high-yielding synthesis of 4,5,6,7-tetrahydro[1,2,3]triazolo-[1,5-a]pyrazin-6-one using the Huisgen 1,3-dipolar cycloaddition of azide onto an alkyne. The starting material is easily synthesized in good yield in two steps from the parent amine. In the case of chirally pure amino acids, enantiopure cyclized compounds were obtained.