Diastereoselective Synthesis of Pyrazolo[1,2-a][1,2,4]triazine Derivatives via Cross-1,3-dipolar Cyclizations of Azaoxyallyl Cations with N,N'& nbsp;-Cyclic Azomethine Imines

A cross-1,3-dipolar cycloaddition reaction of a-halohydroxamates (in situ generated azaoxyallyl cations) with N,N'-cyclic azomethine imines was developed. The synthetic protocol provided facile and rapid access to pyrazolo[1,2-a][1,2,4]triazine derivatives in good yields and excellent diastereoselectivities under mild metal-free conditions.

Automated summary

A cross-1,3-dipolar cycloaddition reaction between α-halohydroxamates (azaoxyallyl cations generated in situ) and N,N'-cyclic azomethine imines was developed. The synthetic protocol provided a facile and rapid access to pyrazolo[1,2-a][1,2,4]triazine derivatives with good yields and excellent diastereoselectivities under mild metal-free conditions.