Palladium(II)-Catalyzed Nondirected C(sp2)–H Alkoxycarbonylation of Arenes

Aromatic carboxylic acid derivatives are ubiquitous structural motifs in organic chemistry, finding widespread use as synthetic intermediates or target compounds for various applications. An ideal way to access these compounds is by C–H functionalization of a simple arene with a C1-building block like CO. State of the art methods however require the use of pre-functionalized arenes or substrates bearing directing groups, which negatively impact the step economy and/or significantly limit the scope of such processes. Herein we describe Pd-catalysts for the nondirected C–H alkoxycarbonylation of simple arenes. The protocol offers a highly efficient approach towards the synthesis of aromatic esters and enables the functionalization of a broad range of substrates. The predominantly sterically controlled regioselectivity renders the process complementary to electrophilic aromatic substitution reactions. We demonstrate the synthetic versatility of the obtained products to access further carboxylic acid derivatives.