Synthesis of enantiopure β-amino alcohols via AKR/ARO of epoxides using recyclable macrocyclic Cr(III) salen complexes

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.

Development of recyclable chiral macrocyclic metal complexes for asymmetric aminolysis of epoxides: application for the synthesis of an enantiopure oxazolidine ring

Macrocyclic Cr(iii)-salen complexes were synthesized for the ring opening reaction of various epoxides with anilines to furnish the corresponding β-amino-α-hydroxyl esters and β-amino alcohols with excellent ee/yield upto 99/95%.

Asymmetric ring-opening reaction of meso-epoxides with aromatic amines using homochiral metal–organic frameworks as recyclable heterogeneous catalysts

Asymmetric ring-opening reactions of meso-epoxides by aromatic amines were achieved by using some chiral metal–organic frameworks. The corresponding β-amino alcohols were obtained with good yields and enantioselectivities (up to 97% ee).

The mechanism of an asymmetric ring-opening reaction of epoxide with amine catalyzed by a metal–organic framework: insights from combined quantum mechanics and molecular mechanics calculations

QM/MM computations suggest that the asymmetric ring-opening reaction of epoxide with amine is controlled by CH–π interactions between aniline and a naphthol moiety.

Chiral Co(iii)–salen complex supported over highly ordered functionalized mesoporous silica for enantioselective aminolysis of racemic epoxides

New mesoporous chiral Co(iii)-catalyst has been synthesed and used in the synthesis of chiral β-amino alcohols with excellent yield and enantioselectivity (ee > 99%) under neat conditions at RT.

A new chiral Fe(iii)–salen grafted mesoporous catalyst for enantioselective asymmetric ring opening of racemic epoxides at room temperature under solvent-free conditions

A new heterogeneous chiral Fe(iii)–salen grafted mesoporous catalyst has been synthesized for the enantioselective (ee > 99%) ARO reaction of racemic epoxides with aromatic amine under solvent-free conditions.

Enantioselective syntheses of β-amino alcohols catalyzed by recyclable chiral Fe(iii) metal complex

An efficient asymmetric desymmetrization of meso-epoxides with anilines catalyzed by a series of simple and environmentally benign in situ generated Fe(iii) complexes based on chiral tridentate ligands L1–L7 was carried out at rt.

Kinetic resolution of 2,3-epoxy 3-aryl ketones via catalytic asymmetric ring-opening with pyrazole derivatives

A highly efficient catalytic kinetic resolution of 2,3-epoxy 3-aryl ketones via asymmetric ring-opening with pyrazole derivatives has been achieved by using a chiral N,N′-dioxide–Sc(iii) complex as the catalyst.

A broadly applicable and practical oligomeric (salen) Co catalyst for enantioselective epoxide ring-opening reactions

The (salen) Co catalyst (4a) can be prepared as a mixture of cyclic oligomers in a short, chromatography-free synthesis from inexpensive, commercially available precursors. This catalyst displays remarkable enhancements in reactivity and enantioselectivity relative to monomeric and other multimeric (salen) Co catalysts in a wide variety of enantioselective epoxide ring-opening reactions. The application of catalyst 4a is illustrated in the kinetic resolution of terminal epoxides by nucleophilic ring-opening with water, phenols, and primary alcohols; the desymmetrization of meso epoxides by addition of water and carbamates; and the desymmetrization of oxetanes by intramolecular ring opening with alcohols and phenols. The favorable solubility properties of complex 4a under the catalytic conditions facilitated mechanistic studies, allowing elucidation of the basis for the beneficial effect of oligomerization. Finally, a catalyst selection guide is provided to delineate the specific advantages of oligomeric catalyst 4a relative to (salen) Co monomer 1 for each reaction class.

Asymmetric hydrolytic kinetic resolution with recyclable polymeric Co(iii)–salen complexes: a practical strategy in the preparation of (S)-metoprolol, (S)-toliprolol and (S)-alprenolol: computational rationale for enantioselectivity

Role of chiral/achiral linker in asymmetric HKR of terminal epoxides using recyclable polymeric Co(iii) salen complexes.