Synthesis of polycarbonyl compounds by cobalt-catalysed Diels-Alder / ozonolysis or cobalt-catalysed 1,4-hydrovinylation / ozonolysis reaction sequences

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The cobalt-catalysed meta-selective Diels-Alder reaction as well as the cobalt-catalysed 1,4-hydrovinylation reaction generate 1,4-dienes with a high tolerance towards many functional groups. The 1,4-dienes obtained allow us to generate 1,3-dicarbonyl compounds by ozonolysis or other double bond cleaving reactions. Tri-, tetra- or higher polycarbonyl compounds become accessible when incorporating additional double bonds in the starting material, thus allowing a rapid increase in complexity by exceedingly short reaction sequences. An atom economic approach towards polycarbonyl derivatives is realised when symmetrical dihydroaromatic compounds are used in the ozonolysis reaction generating two identical products. The synthesis and especially the handling and characterisation of these tri-, tetra- and polycarbonyl compounds is a challenging task which we will address by complexation of the 1,3-dicarbonyl subunit with a BF2 fragment. Within these complexes the boron acts as a protecting group for the 1,3-dicarbonyl subunit, so that functional group transformations on additional uncomplexed carbonyl groups seem possible. Prototype reactions will be performed to investigate possible followup transformations towards increasingly complex products.