Direct C7‐H Arylation of Pyrazolo[1,5‐a]azines with Aryl Chlorides

Abstract

C7‐Arylated pyrazolo[1,5‐a]azines are important structural motifs with profound applications in drug and material research. Here, we report a general and straighforward synthesis of these bi(hetero)aryls via palladium‐catalyzed direct C−H arylation, employing low‐cost and abundant (hetero)aryl chlorides as the aryl source. The catalytic system is robust and covers a wide substrate scope regarding heteroarenes as well as (hetero)aryl chlorides, with possible extension to the C−H arylation of [1,2,4]triazolo[1,5‐a]pyrimidines. This study also presents a rare example of using (hetero)aryl chlorides for the direct C−H arylation of six‐membered heteroarenes.