"On-Water" Palladium-Catalyzed Tandem Cyclization Reaction for the Synthesis of Biologically Relevant 4-Arylquinazolines.

The quinazoline scaffold is prevalent in pharmaceutically relevant molecules that show diverse biological activities. Herein, we report an efficient "on-water" palladium-catalyzed tandem cyclization reaction from commercially available arylboronic acids and benzonitriles that enable the rapid access to 4-arylquinazoline scaffolds in good to excellent yields (45 examples, up to 98 % yield). This protocol has shown good functional group tolerance and broad substrate scope. The reaction was also performed on a gram scale and successfully applied to the synthesis of the highly potent and selective PI3Kδ inhibitor N11, showing the practicability and synthetic utility of the protocol. In this reaction, the quinazoline scaffold is efficiently constructed with the simultaneous formation of one C-C bond and one C-N bond. Collectively, the protocol could serve as an alternative strategy to synthesize biologically important quinazoline scaffolds.