Organocatalyst-controlled site-selective arene C–H functionalization

Over the past three decades, organocatalysis has emerged as a powerful catalysis platform and has gradually been incorporated into the routine synthetic toolbox to obtain chiral molecules. However, its application in the site- and enantioselective functionalization of inactive aryl C–H bonds remains in its infancy. Here, we present an organocatalyst-controlled para-selective arene C–H functionalization strategy that addresses this issue, which remains an enduring challenge in arene functionalization chemistry. By emulating enzyme catalysis, the chiral phosphoric acid catalyst offers an ideal chiral environment for stereoinduction, and the projecting substituents give control of chemo- and site-selectivity. Various types of nucleophile are compatible with this method, affording more than 100 para-selective adducts with stereodefined carbon centres or axes in viable molecular contexts. This protocol is expected to provide a general strategy for para-selective functionalization of arene C–H bonds in a controlled manner. Although organocatalysis has emerged as a powerful catalysis platform, its application for the selective transformation of inactive arenes remains challenging. Now, an organocatalyst-controlled site-selective C–H functionalization of arenes has been developed, with wide substrate generality and applicability, offering a general strategy for arene transformation.