Selective catalytic formation of unsaturated amino acids from petrochemicals and carbon dioxide—Application of high-throughput catalyst screening

The atom economic hydroamination, the addition of an amine to an alkene, gained more and more importance as an “eco-friendly” alternative in amine synthesis. In this work the homogeneous catalytic 1,4-hydroamination of an unsaturated δ-lactone the 2-ethylidene-6-heptene-5-olide is investigated leading to a selective formation of an amino acid in a single step. The δ-lactone can be obtained by the telomerisation of the easily accessible 1,3-butadiene and the green house gas carbon dioxide. A new reactor concept is introduced which allows practical high-throughput catalyst screening with low costs. Variation of the metal precursors and the phosphorous ligands, optimisation of temperature and determinations of reaction rates leads to the catalyst system Al(OTf)3/DPEphos, which combines high activity (TOF = 846 h−1), no side products, low costs and low toxicity.