New heterogeneous catalysts for the synthesis of chiral amino acids: Functionalization of organic resins with chiral salen complexes

Esteves, M. Alexandra; Gigante, Bárbara; Santos, Caio Y. dos; Guerreiro, Ana M. G.; Baleizão, Carlos

doi:10.1016/j.cattod.2013.06.022

Cited by 18 publications

(8 citation statements)

References 23 publications

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“…The preparation of isolated, well-defined, supported vanadium complexes therefore presents a significant scientific interest. − Several strategies have been employed to prepare well-defined immobilized vanadium catalysts on mesoporous materials, zeolites, graphene oxide, and polymers . Supported oxo-vanadium complexes are catalytically active for the oxidation of alkanes and alkenes, − epoxidation, − oxo-bromination, − sulfur oxidation, − and others. − It is unclear whether these supported complexes operate with the same catalytic reaction mechanisms as their homogeneous analogues due to the difficulties in characterizing surface sites and reaction intermediates in supported systems.…”

Section: Supported Well-defined Vanadium Catalystsmentioning

confidence: 75%

Catalytic Applications of Vanadium: A Mechanistic Perspective

et al. 2018

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The chemistry of vanadium has seen remarkable activity in the past 50 years. In the present review, reactions catalyzed by homogeneous and supported vanadium complexes from 2008 to 2018 are summarized and discussed. Particular attention is given to mechanistic and kinetics studies of vanadium-catalyzed reactions including oxidations of alkanes, alkenes, arenes, alcohols, aldehydes, ketones, and sulfur species, as well as oxidative C–C and C–O bond cleavage, carbon–carbon bond formation, deoxydehydration, haloperoxidase, cyanation, hydrogenation, dehydrogenation, ring-opening metathesis polymerization, and oxo/imido heterometathesis. Additionally, insights into heterogeneous vanadium catalysis are provided when parallels can be drawn from the homogeneous literature.

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Section: Supported Well-defined Vanadium Catalystsmentioning

confidence: 75%

Catalytic Applications of Vanadium: A Mechanistic Perspective

et al. 2018

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“…The solid-supported catalysts were characterized by typical solid state analytical and spectroscopic techniques, and they were tested for the Strecker type reaction. However, these showed quite modest results in the case of Al(salen) complexes [41]. Peters reported a recent improvement for the preparation of a cooperative catalyst (Scheme 4) [42,43].…”

Section: Addition Of Cn To Electrophiles Promoted By Chiral Al(salmentioning

confidence: 99%

Al(Salen) Metal Complexes in Stereoselective Catalysis

et al. 2019

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Salen ligands are a class of Schiff bases simply obtained through condensation of two molecules of a hydroxyl-substituted aryl aldehyde with an achiral or chiral diamine. The prototype salen, or N,N′-bis(salicylidene)ethylenediamine has a long history, as it was first reported in 1889, and immediately, some of its metal complexes were also described. Now, the salen ligands are a class of N,N,O,O tetradentate Schiff bases capable of coordinating many metal ions. The geometry and the stereogenic group inserted in the diamine backbone or aryl aldehyde backbone have been utilized in the past to efficiently transmit chiral information in a variety of different reactions. In this review we will summarize the important and recent achievements obtained in stereocontrolled reactions in which Al(salen) metal complexes are employed. Several other reviews devoted to the general applications and synthesis of chromium and other metal salens have already been published.

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“…Recent examples of such a strategy involving immobilization of salen derivatives are becoming scarcer, but some chiral catalytic organic polymers are still constructed from preformed enantiopure salen complexes. In a recent contribution, V‐ and Al‐salen complexes were covalently attached to Merrifield and JandaJel resins, for the synthesis of scalemic amino acid derivatives through the Strecker reaction. V(V)‐salen complexes linked to a JandaJel resin were the most productive however without completely reaching the ee values obtained by the homogeneous analogues.…”

Section: Grafting Of Salen Complexes On Organic Supportsmentioning

confidence: 99%

Chiral Salen Complexes for Asymmetric Heterogeneous Catalysis: Recent Examples for Recycling and Cooperativity

2019

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Chiral salen complexes are privileged and versatile catalysts used in a wide variety of enantioselective transformations. Researches for their use in multicatalysis, including cooperative as well as tandem processes, are more recent, but many reports already highlight the important effect of the salen ligand structure on reaction rates and/or selectivities. This review article thus outlines the literature covering last five years, on the current developments of chiral polymetallic salen complexes used in asymmetric heterogeneous catalysis; their preparation, their efficiency as catalysts in various reactions and their recyclability are highlighted according to the immobilization procedures involved for their heterogenization. These methods include grafting on organic or inorganic supports insuring easy recovery by simple filtration. Polymerization processes are also part of recent research, leading to high densities of catalytic sites to favor their cooperativity. Combination of salen complexes via non covalent interactions or their introduction on MOFs and COFs networks is currently in full expansion, with examples of highly functionalized and enantioenriched products issued from tandem catalysis.

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New heterogeneous catalysts for the synthesis of chiral amino acids: Functionalization of organic resins with chiral salen complexes

Cited by 18 publications

References 23 publications

Catalytic Applications of Vanadium: A Mechanistic Perspective

Catalytic Applications of Vanadium: A Mechanistic Perspective

Al(Salen) Metal Complexes in Stereoselective Catalysis

Chiral Salen Complexes for Asymmetric Heterogeneous Catalysis: Recent Examples for Recycling and Cooperativity

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