Chiral Pentacoordinated Manganese Complexes As Biomimetic Catalysts for Asymmetric Epoxidations with Hydrogen Peroxide

Berkessel, Albrecht; Schwenkreis, Thomas; Frauenkron, Matthias; Steinmetz, Adrian; Schatz, Norbert; Prox, Jochen

doi:10.1002/3527600396.ch24

Cited by 4 publications

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“…Subsequently, the epoxidation of 1,2-dihydronaphthalene ( 68 ) with 10 mol % of M52 and H 2 O 2 as the oxidant provided epoxide (1a S ,7b R )- 69 in 72% yield with an enantioselectivity of 64% ee (Scheme a). Following this promising result, they later synthesized various derivatives of this catalyst system for asymmetric epoxidations. , …”

Section: Stereogenic-at-metal Catalysts From Chiral Ligandsmentioning

confidence: 99%

“…Following this promising result, they later synthesized various derivatives of this catalyst system for asymmetric epoxidations. 144,145 In 2018, Sun introduced a tripodal, proline-derived, pentadentate ligand and demonstrated its predetermination of the metal center for the complexation with iron(II) 146 and manganese(II). 147 Despite the tertiary amine moiety bearing two identical methyl-pyridinyl groups, the facial coordination of this motif induces a stereogenic metal center with two possible diastereomers.…”

Section: Hexacoordinated Catalysts From Chiral Pentadentate Ligands O...mentioning

confidence: 99%

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Metal Stereogenicity in Asymmetric Transition Metal Catalysis

2023

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Chiral transition metal catalysts represent a powerful and economic tool for implementing stereocenters in organic synthesis, with the metal center providing a strong chemical activation upon its interaction with substrates or reagents, while the overall chirality of the metal complex achieves the desired stereoselectivity. Often, the overall chiral topology of the metal complex implements a stereogenic metal center, which is then involved in the origin of the asymmetric induction. This review provides a comprehensive survey of reported chiral transition metal catalysts in which the metal formally constitutes a stereocenter. A stereogenic metal center goes along with an overall chiral topology of the metal complex, regardless of whether the ligands are chiral or achiral. Implications for the catalyst design and mechanism of asymmetric induction are discussed for half-sandwich, tetracoordinated, pentacoordinated, and hexacoordinated chiral transition metal complexes containing a stereogenic metal center. The review distinguishes between chiral metal catalysts originating from the coordination to chiral ligands and those which are solely composed of optically inactive ligands (achiral or rapidly interconverting enantiomers) prior to complexation (dubbed “chiral-at-metal” catalysts).

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Section: Stereogenic-at-metal Catalysts From Chiral Ligandsmentioning

confidence: 99%

Section: Hexacoordinated Catalysts From Chiral Pentadentate Ligands O...mentioning

confidence: 99%

Metal Stereogenicity in Asymmetric Transition Metal Catalysis

2023

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Synthesis of Metal–(Pentadentate‐Salen) Complexes: Asymmetric Epoxidation with Aqueous Hydrogen Peroxide and Asymmetric Cyclopropanation (salenH₂: N,N′‐bis(salicylidene)ethylene‐1,2‐diamine)

Shitama

Katsuki

2007

Chemistry A European J

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It is known that the rates and stereochemical outcomes of epoxidations and cyclopropanations using a metallosalen (salenH(2): N,N'-bis(salicylidene)ethylene-1,2-diamine) complex as catalyst are affected by a trans effect of the apical ligand of the complex. By taking into consideration this trans effect, we have synthesized optically active pentadentate salen ligands bearing an imidazole or pyridine derivative as the fifth coordinating group, and have prepared the corresponding manganese(III) and cobalt(II) complexes, in which the fifth ligand is expected to intramolecularly coordinate to the metal center and exert a trans effect. Indeed, high enantioselectivity has been achieved in epoxidations using aqueous hydrogen peroxide as the terminal oxidant and in cyclopropanations with these complexes as catalysts. In general, metallosalen-catalyzed reactions have been carried out in the presence of an excess of a donor ligand; however, the present reactions do not need the addition of any extra donor ligand.

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ChemInform Abstract: Chiral Pentacoordinated Manganese Complexes as Biomimetic Catalysts for Asymmetric Epoxidations with Hydrogen Peroxide

Berkessel¹,

Schwenkreis²,

Frauenkron³

et al. 2001

ChemInform

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Chiral Pentacoordinated Manganese Complexes As Biomimetic Catalysts for Asymmetric Epoxidations with Hydrogen Peroxide

Cited by 4 publications

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Metal Stereogenicity in Asymmetric Transition Metal Catalysis

Metal Stereogenicity in Asymmetric Transition Metal Catalysis

Synthesis of Metal–(Pentadentate‐Salen) Complexes: Asymmetric Epoxidation with Aqueous Hydrogen Peroxide and Asymmetric Cyclopropanation (salenH₂: N,N′‐bis(salicylidene)ethylene‐1,2‐diamine)

ChemInform Abstract: Chiral Pentacoordinated Manganese Complexes as Biomimetic Catalysts for Asymmetric Epoxidations with Hydrogen Peroxide

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Chiral Pentacoordinated Manganese Complexes As Biomimetic Catalysts for Asymmetric Epoxidations with Hydrogen Peroxide

Cited by 4 publications

References 0 publications

Metal Stereogenicity in Asymmetric Transition Metal Catalysis

Metal Stereogenicity in Asymmetric Transition Metal Catalysis

Synthesis of Metal–(Pentadentate‐Salen) Complexes: Asymmetric Epoxidation with Aqueous Hydrogen Peroxide and Asymmetric Cyclopropanation (salenH2: N,N′‐bis(salicylidene)ethylene‐1,2‐diamine)

ChemInform Abstract: Chiral Pentacoordinated Manganese Complexes as Biomimetic Catalysts for Asymmetric Epoxidations with Hydrogen Peroxide

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Synthesis of Metal–(Pentadentate‐Salen) Complexes: Asymmetric Epoxidation with Aqueous Hydrogen Peroxide and Asymmetric Cyclopropanation (salenH₂: N,N′‐bis(salicylidene)ethylene‐1,2‐diamine)