Multisite modifications of arenes using ketones as removable handles enabled by Pd and norbornene cooperative catalysis

Abstract

Natural products serve as crucial sources for new drugs and play an indispensable role in drug discovery. Late-stage functionalization of natural products is an efficient method for diversifying their structures, fine-tuning their biological properties and rapidly constructing molecular libraries. Polysubstituted arenes serve as structural cores in pharmaceuticals derived from natural products. However, programmable multisite arene modification remains a largely unmet challenge. Here, using commercially available and easy-to-synthesize aryl ketones as substrates, we present the programmable multifunctionalization of natural products via a palladium- and norbornene-catalysed Catellani-type reaction. Given the ease of installing an acyl group and using it as a relay, this protocol enables the incorporation of a variety of bioactive molecules into natural products via successive acylation and deacylation processes. Furthermore, this strategy was applied to the construction of a molecular library based on dehydroabietic acid. Multiple molecules with substantially increased activity were obtained through antimicrobial activity screening. Polysubstituted arenes are ubiquitous structural cores in natural products and drugs but their synthesis through programmable arene modification remains a challenge. Now, a palladium- and norbornene-catalysed Catellani-type reaction of aryl ketones, through successive acylation and deacylation, allows the synthesis of polysubstituted arenes.