Sequential S(N)Ar Reaction/Suzuki-Miyaura Coupling/C-H Direct Arylations Approach for the Rapid Synthesis of Tetraaryl-Substituted Pyrazoles

Abstract

A rapid synthesis of 1,3,4,5-tetraaryl-substituted pyrazoles has been achieved through a sequence of SN Ar reaction/Suzuki-Miyaura coupling/Pd-catalyzed direct arylations that used 3-iodo-1H-pyrazole as a scaffold. Pyrazoles with four different aryl groups were synthesized in a straightforward manner with no extra synthetic steps, such as protection/deprotection or the introduction of activating/directing groups, using readily available substrates and reagents. The developed synthetic approach enabled the structurally diverse synthesis of multiaryl-substituted pyrazoles without using a glovebox technique.

Keywords: C-H activation; cross-coupling; heterocycles; palladium; synthetic methods.