Highly Enantioselective Transfer Hydrogenation of Prochiral Ketones Using Ru(II)‐Chitosan Catalyst in Aqueous Media

Szőllősi, György; Kolcsár, Vanessza Judit

doi:10.1002/cctc.201801602

Cited by 21 publications

(21 citation statements)

References 113 publications

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“…Then, this adduct was treated with [Ru( p -cymene)Cl 2 ] 2 in methanol. The obtained product was tested in the asymmetric transfer hydrogenation of acetophenone [ 258 , 259 ]. One of the main drawbacks of this catalyst were its degradation and precipitation under basic conditions [ 258 ].…”

Section: Applications Of Chitosanmentioning

confidence: 99%

Chitosan: A Natural Biopolymer with a Wide and Varied Range of Applications

2020

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Although chitin is of the most available biopolymers on Earth its uses and applications are limited due to its low solubility. The deacetylation of chitin leads to chitosan. This biopolymer, composed of randomly distributed β-(1-4)-linked D-units, has better physicochemical properties due to the facts that it is possible to dissolve this biopolymer under acidic conditions, it can adopt several conformations or structures and it can be functionalized with a wide range of functional groups to modulate its superficial composition to a specific application. Chitosan is considered a highly biocompatible biopolymer due to its biodegradability, bioadhesivity and bioactivity in such a way this biopolymer displays a wide range of applications. Thus, chitosan is a promising biopolymer for numerous applications in the biomedical field (skin, bone, tissue engineering, artificial kidneys, nerves, livers, wound healing). This biopolymer is also employed to trap both organic compounds and dyes or for the selective separation of binary mixtures. In addition, chitosan can also be used as catalyst or can be used as starting molecule to obtain high added value products. Considering these premises, this review is focused on the structure and modification of chitosan as well as its uses and applications.

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Section: Applications Of Chitosanmentioning

confidence: 99%

Chitosan: A Natural Biopolymer with a Wide and Varied Range of Applications

2020

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“…In fact, these results were recently defined as "uncertain, irreproducible". [35] However, they challenge the idea of using chitosan as chiral ligand for transition metals. At any rate, it may be argued that the potential of the homochirality of this biopolymer for enantioselective reductions was unlocked only more recently, when two laboratories described their investigations on the combination of ruthenium and chitosan for the transfer hydrogenation of ketones.…”

Section: Marine Polysaccharides As Chiral Inducing Elements In Catalytic Enantioselective Reactionsmentioning

confidence: 99%

“…More recently, Szőllősi and co-workers reported an interesting and ample study on the combination of ruthenium and chitosan for the transfer hydrogenation of ketones. [35,38] Compared to the approach reported in Scheme 16 with O6-esterified chitosan, these authors simplified the system by complexing the ruthenium salt [Ru(p-cymene)Cl2]2 with unmodified, high molecular weight, chitosan, resulting in Ch18 (Scheme 17). This complex, prepared in situ, was then tested in the transfer hydrogenation of acetophenone.…”

Section: Marine Polysaccharides As Chiral Inducing Elements In Catalytic Enantioselective Reactionsmentioning

confidence: 99%

Blue Chemistry. Marine Polysaccharide Biopolymers in Asymmetric Catalysis: Challenges and Opportunities

et al. 2020

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Alginate, chitin (precursor of chitosan) and carrageenan are natural polysaccharides derived from marine sources and available in nearly unlimited amounts. In contrast with other natural polysaccharides (i.e. cellulose), their monomers bear functional groups (amine, carboxylate, sulfate). These functional groups can be used to anchor catalytic species, or even as catalytically active units. In this mini-review, the utilization of marine polysaccharides in asymmetric catalysis is discussed. Examples include: i) combinations with chiral catalysts, resulting in heterogeneous catalytic systems, and ii) utilization of the biopolymers as chirality inducing elements -serving as chiral ligands or organocatalysts. The reviewed works propose innovative and unconventional utilizations of these renewable materials, providing not only a useful alternative to oil-based polymers, but also unforeseen and fascinating opportunities in the field of asymmetric catalysis.

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“…However, in previous biocatalytic studies, the product was not obtained enantiomerically pure form. To date, this product was also prepared by metal catalyzed hydrogenation . However, the production of chiral ligands is generally complex and costly, and the molecules themselves are harmful to the environment.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of enantiopure (S)‐6‐chlorochroman‐4‐ol using whole‐cell Lactobacillus paracasei biotransformation

Şahin

2020

Chirality

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Chromane, which has a fused cyclic structure, is a significant molecule that can be found in the structure of many important compounds. Lactobacillus paracasei BD101 was demonstrated as whole‐cell biocatalyst for the synthesis of (S)‐6‐chlorochroman‐4‐ol with immense enantioselectivity. The conditions of asymmetric reduction were optimized one factor by one factor using L paracasei BD101 to achieve enantiomerically pure product and complete conversion. Using these obtained optimization conditions, asymmetric reduction of 6‐chlorochroman‐4‐one was performed under environmentally friendly conditions; 6‐chlorochroman‐4‐one, having a fused cyclic structure as previously noted to be difficult to asymmetric reduction with biocatalysts, was enantiomerically reduced to (S)‐6‐chlorochroman‐4‐ol with an enantiomeric excess >99% on a high gram scale. This study is the first example in the literature for the enantiopure synthesis of (S)‐6‐chlorochroman‐4‐ol using a biocatalyst. Also notably, the optical purity of (S)‐6‐chlorochroman‐4‐ol obtained in this study through asymmetric bioreduction using whole‐cell biocatalyst is the highest value in the literature. In this study, (S)‐6‐chlorochroman‐4‐ol was produced on a gram scale by an easy, inexpensive, and environmentally friendly method, which has shown the production of valuable chiral precursors for drug synthesis and other industrial applications. This study provides a convenient method for the production of (S)‐6‐chlorochroman‐4‐ol, which can meet the industrial green production demand of this chiral secondary alcohol.

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Highly Enantioselective Transfer Hydrogenation of Prochiral Ketones Using Ru(II)‐Chitosan Catalyst in Aqueous Media

Cited by 21 publications

References 113 publications

Chitosan: A Natural Biopolymer with a Wide and Varied Range of Applications

Chitosan: A Natural Biopolymer with a Wide and Varied Range of Applications

Blue Chemistry. Marine Polysaccharide Biopolymers in Asymmetric Catalysis: Challenges and Opportunities

Synthesis of enantiopure (S)‐6‐chlorochroman‐4‐ol using whole‐cell Lactobacillus paracasei biotransformation

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