Photocatalyst-Free Visible-Light-Promoted C-H Selenylation of Pyrazolo[1,5-a ]pyrimidines

A new method has been developed for the C-H selenylation of pyrazolo[1,5-a]pyrimidine derivatives under the irradiation of visible light. This photocatalyst-free strategy is applicable to a wide range of pyrazolo[1,5-a]pyrimidines with broad functionalities. The salient features of the method are mild reaction conditions, use of bench-stable oxidant, high regioselectivity, and scalability.