Asymmetric Counteranion-Directed Catalysis for the Epoxidation of Enals


  • We thank Simone Marcus, Esther Böß, and Jutta Rosentreter for technical assistance. Generous support by the Max Planck Society, the DFG (SPP 1179, Organokatalyse), and Novartis (Young Investigator Award to B.L.) is gratefully acknowledged. We also thank BASF, Degussa, Merck, Saltigo, and Wacker for general support and for donating chemicals.


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A new mode of chiral anion catalysis: A powerful chiral-counteranion strategy for catalytic asymmetric epoxidations using the newly discovered catalyst 1 has been applied to the epoxidation of α,β-unsaturated aldehydes together with tert-butyl hydroperoxide as the oxidant (see scheme). Remarkably, this system provides the corresponding epoxides in high diastereo- and enantioselectivity for both di- and trisubstituted enals.