Pd-Catalyzed Synthesis of C4-Aryl Pyrimidinone Nucleoside Analogues

A two-step synthesis of C4-aryl pyri­midinone nucleoside analogues from readily available thymidine is described, which involves O4-arylsulfonylation and then Suzuki cross-coupling reaction of arylboronic acids with the derived O4-mesylates. Most of the coupling reactions proceed efficiently at room temperature in toluene, and electron-deficient arylboronic acids may also be cross-coupled at elevated temperature in THP.