A General Synthesis of Bis-α-acyloxy-1,4-and -1,5-diketones Through Catalytic Oxidative Opening of Acylated THF and THP Diols

The first general synthesis of bis-alpha-acyloxy-1,4- and -1,5-diketones has been accomplished in a catalytic oxidative opening of bis-acylated THF and THP (tetrahydropyran) diols, which were synthesised by osmium- or ruthenium-catalysed oxidative cyclisation of 1,5- and 1,6-dienes. The overall sequence corresponds to the regioselective double ketoacylox-ylation of the starting diene. The synthesised bis-alpha-acyloxy-1,5-dicarbonyl compounds have been transformed into pyridine-based oxido pincer ligands or pyrazinedimethanol substances, leading to the discovery of unprecedented aromatisation routes.