A new tandem catalysis was set up after intensive investigations regarding the amino catalysed aldol condensation and epoxidation. 20 proteinogenic amino acids were investigated as organocatalysts in the epoxidation of an alpha-branched alpha,beta-unsaturated aldehyde. The most active amino acids were chosen for the optimization of the reaction conditions obtaining excellent yields in the epoxidation. With these insights the first tandem aldol condensation/epoxidation was developed gaining very good yields of the epoxy aldehyde, which was obtained directly from butanal without any purification or isolation of the intermediate. Applying butanal as substrate, which is produced on a large industrial scale, opens up new horizons for novel useful and reactive products. Furthermore, the beneficial influence of lysine and arginine was proven and it was revealed that these amino acids bear two different catalytic centres, which have impact on the synergy in this new tandem catalysis being active within two different reaction mechanisms. The alpha-amino function catalyses the aldol condensation and the corresponding side chain group is responsible for the catalytically conversion in the epoxidation. (C) 2015 Elsevier B.V. All rights reserved.