Asymmetric Ring-Opening of Epoxides Catalyzed by Metal–Salen Complexes

The asymmetric ring-opening of epoxides is an important reaction in organic synthesis, since it allows for the enantioselective installation of two vicinal functional groups with specific stereochemistry within one step from a highly available starting material. An effective class of catalysts for the asymmetric ring-opening of epoxides is metal–salen complexes. This review summarizes the development of metal–salen catalyzed enantioselective desymmetrization of meso-epoxides and kinetic resolution of epoxides with various nucleophiles, including the design and application of both homogeneous- and heterogeneous epoxide-opening catalysts as well as multi-metallic covalent and supramolecular catalytic systems.

Catalytic Asymmetric Transformations of Racemic Aziridines

The catalytic asymmetric ring-opening transformations of aziridines represent an important strategy for the construction of various chiral nitrogen-containing molecular architectures. This short review covers the progress achieved in the catalytic asymmetric transformation of racemic aziridines, focusing on the catalytic strategies employed for each different type of such aziridines.1 Introduction2 Reaction of Racemic 2-Vinylaziridines3 Reaction of Racemic 2-Alkylaziridines3.1 Regiodivergent Parallel Kinetic Resolution3.2 Kinetic Resolution4 Reaction of Racemic 2-(Hetero)arylaziridines4.1 Kinetic Resolution4.2 Enantioconvergent Transformation5 Reaction of Racemic Donor–Acceptor-Type Aziridines6 Conclusion and Outlook