Treatment of the sulfonamide 9a with MCPBA or NBS gave the pyridinone 10a in 99% yield (Scheme [4] ). Previous aromatisations of pyridinones have used acid catalysis to promote dehydration and, hence, aromatisation. [9] [10] We investigated the aromatisation of the pyridinone 10a in the presence of a range of Lewis acids (Scheme [4] ); selected examples are described in Table [2] . The yield of the pyridine 11a increased with the strength of the Lewis acid (for ...