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

#### **Anna Lidskog** †**, Yutang Li** † **and Kenneth Wärnmark \***

Centre for Analysis and Synthesis, Lund University, P.O Box 124, SE-22100 Lund, Sweden;

Anna.Lidskog@chem.lu.se (A.L.); Yutang.Li@chem.lu.se (Y.L.)

**\*** Correspondence: kenneth.warnmark@chem.lu.se; Tel.: +46-46-222-8217

† These authors equally contributed to this work.

Received: 4 June 2020; Accepted: 18 June 2020; Published: 23 June 2020

**Abstract:** 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.

**Keywords:** asymmetric catalysis; salen complexes; ring-opening; epoxide; kinetic resolution
