Facile synthesis of pyrazoles via [3 + 2] cycloaddition of diazocarbonyl compounds and enones
作者:Guipeng Feng、Shaohong Xu、Rongxiang Chen、Wenyan Chen、Kai-Kai Wang、Shaoyan Wang
DOI:10.1016/j.tetlet.2020.152622
日期:2020.12
A facile and efficient [3 + 2] cycloaddition reaction of diazocarbonyl compounds with enones has been achieved, which represents facile and straightforward access to pyrazoles in moderate to good yields. The present methodology is characterized by readily available starting materials, operational simplicity, and wide substrate scope.
generates diazoester anion, a reactive 1,3-dipole, which undergoes [3+2] annulation with chalcones to afford pyrazole ketoesters. Under similar conditions, the 1,3-dipole takes part in a [3+3] annulation with chalcone epoxides to provide pyridazine esters. Despite moderate yields, high regioselectivity, mild conditions, and functional group diversity are the salient features of this novel methodology.