A new functionalized, chiral disulfide derived from l-cysteine: (R,R)-bis[(3-benzyloxazolan-4-yl)-methane] disulfide as a catalyst in the diethylzinc addition to aldehydes

Braga, Antônio L.; Appelt, Helmoz R.; Schneider, Paulo H.; Silveira, Cláudio C.; Wessjohann, Ludger A.

doi:10.1016/s0957-4166(99)00145-7

Cited by 49 publications

(24 citation statements)

References 21 publications

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“…This ligand was applied in the addition of diethylzinc to several aromatic and aliphatic aldehydes and enantioselectivities of up to >99% were achieved when 2 mol% of the catalyst were used [12].…”

Section: Introductionmentioning

confidence: 99%

A chiral disulfide derived from (R)-cysteine in the enantioselective addition of diethylzinc to aldehydes: loading effect and asymmetric amplification

Braga¹,

Lüdtke²,

Wessjohann³

et al. 2005

Journal of Molecular Catalysis A: Chemical

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Section: Introductionmentioning

confidence: 99%

A chiral disulfide derived from (R)-cysteine in the enantioselective addition of diethylzinc to aldehydes: loading effect and asymmetric amplification

Braga¹,

Lüdtke²,

Wessjohann³

et al. 2005

Journal of Molecular Catalysis A: Chemical

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“…Our strategy to synthesise the CILs 1 and 2 (Scheme ) started with the disulfide 5 , which was obtained in two steps from l ‐cysteine, as described previously. [4a] The disulfide 5 was treated with iodomethane and K 2 CO 3 to provide the disulfide 6 , which, through an esterification with 6‐bromohexanoic acid, furnished 7 in excellent yield. To form the ionic pair, compound 7 was treated with 1,2‐dimethylimidazole in acetonitrile or with pyridine at 65 °C to provide the bromides 1a and 2a , respectively, in quantitative yields.…”

Section: Resultsmentioning

confidence: 99%

“…Ligands derived from amino acids are outstanding due to their easy access from natural sources and to their excellent performance in asymmetric reactions . In this way, our group has described a series of ligands derived from the amino acid l ‐cysteine, which have proved to be very efficient in the enantioselective addition of alkylzinc, alkynylzinc and arylzinc to aldehydes, as well as in palladium‐catalysed asymmetric allylations and enantioselective direct aldol reactions . Some examples of the ligands used in the asymmetric addition of diethylzinc to aldehydes can be seen in Scheme .…”

Section: Introductionmentioning

confidence: 99%

“…As part of our broader program to explore the preparation and use of chiral catalysts in asymmetric synthesis,, we describe in this article the design and synthesis of a new class of chiral ionic liquids derived from l ‐cysteine (see Scheme ) through efficient synthetic routes. To prove our new catalytic system, we envisioned their application in an organometallic reaction, taking into account the importance of replacing volatile organic solvents with clean ones, such as ionic liquids.…”

Section: Introductionmentioning

confidence: 99%

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Design of a Chiral Ionic Liquid System for the Enantioselective Addition of Diethylzinc to Aldehydes

et al. 2017

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An important contribution to the field of asymmetric catalysis is described in this work, as it merges the search for new ligands that can provide high performance in asymmetric catalysis with the extremely important and increasing need for sustainability. New chiral ionic liquids have been synthesised from the amino acid l‐cysteine by straightforward routes. With these ligands, we have developed a chiral ionic system that includes chiral ionic liquids and their immobilisation in ionic solvents to provide a chiral supramolecular structure. These new catalytic systems were used in the enantioselective addition of alkylzinc to aldehydes and proved to be very efficient, capable of providing chiral secondary alcohols in excellent enantiomeric excesses and yields. This system also enabled the recycling of the ionic media and the ionic ligand, taking into account green chemistry considerations.

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“…Porém, poucos grupos efetivamente desenvolvem pesquisas focadas no desenvolvimento de novos catalisadores quirais, 27 sendo que boa parte dos trabalhos desenvolvidos envolvem artigos de grupos pontuais, 28 dentre os quais cabe destacar os avanços recentes que vêm sendo relatados pelo grupo do Prof. Correia no desenvolvimento da versão catalítica e assimétrica da reação de Heck-Matsuda de olefinas cíclicas e acíclicas. 29 Um dos grupos mais consolidados nessa área utiliza como estratégia o desenvolvimento de catalisadores/ligantes provenientes de aminoácidos, que são compostos abundantes de origem natural.…”

Section: Catálise Organometálicaunclassified

Catálise assimétrica no Brasil: desenvolvimento e potencialidades para o avanço da indústria química brasileira

Braga¹,

Lüdtke²,

Schneider³

et al. 2013

Quím. Nova

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Recebido em 11/7/13; aceito em 9/10/13; publicado na web em 24/10/13 ASYMMETRIC CATALYSIS IN BRAZIL: DEVELOPMENT AND POTENTIAL FOR ADVANCEMENT OF BRAZILIAN CHEMICAL INDUSTRY. The preparation of enantiomerically pure or enriched substances is of fundamental importance to pharmaceutical, food, agrochemical, and cosmetics industries and involves a growing market of hundreds of billions of dollars. However, most chemical processes used for their production are not environmentally friendly because in most cases, stoichiometric amounts of chiral inductors are used and substantial waste is produced. In this context, asymmetric catalysis has emerged as an efficient tool for the synthesis of enantiomerically enriched compounds using chiral catalysts. More specifically, considering the current scenario in the Brazilian chemical industry, especially that of pharmaceuticals, the immediate prospect for the use of synthetic routes developed in Brazil in an enantioselective fashion or even the discovery of new drugs is practically null. Currently, the industrial production of drugs in Brazil is primarily focused on the production of generic drugs and is basically supported by imports of intermediates from China and India. In order to change this panorama and move forward toward the gradual incorporation of genuinely Brazilian synthetic routes, strong incentive policies, especially those related to continuous funding, will be needed. These incentives could be a breakthrough once we establish several research groups working in the area of organic synthesis and on the development and application of chiral organocatalysts and ligands in asymmetric catalysis, thus contributing to boost the development of the Brazilian chemical industry. Considering these circumstances, Brazil can benefit from this opportunity because we have a wide biodiversity and a large pool of natural resources that can be used as starting materials for the production of new chiral catalysts and are creating competence in asymmetric catalysis and related areas. This may decisively contribute to the growth of chemistry in our country.Keywords: asymmetric catalysis; chiral compounds; chiral catalyst. INTRODUÇÃOCom o objetivo de fomentar e contribuir na formulação de novas políticas de C&T, especialmente para a área de Química, apresentam--se, nesse artigo, diagnósticos, reflexões e discussões sobre a atual situação da área de Catálise Assimétrica no Brasil. Propõem-se, ainda, ações que permitam à Química do País contribuir para um futuro próspero, seguro e sustentável para sua população. A presente proposta está de acordo com os position papers "Química sem Fronteiras" da Química Nova, 1 nos temas centrais: Indústria Química e Inovação, nos setores farmoquímicos, agroquímicos e de alimentos. Enquadra-se, também, nos temas transversais, nos setores de inovação e agregação de valores.Durante as últimas décadas grandes esforços vêm sendo realizados no sentido de se estabelecer rotas enantiosseletivas para a preparação de substâncias enantiomericamente puras ou enriq...

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A new functionalized, chiral disulfide derived from l-cysteine: (R,R)-bis[(3-benzyloxazolan-4-yl)-methane] disulfide as a catalyst in the diethylzinc addition to aldehydes

Cited by 49 publications

References 21 publications

A chiral disulfide derived from (R)-cysteine in the enantioselective addition of diethylzinc to aldehydes: loading effect and asymmetric amplification

A chiral disulfide derived from (R)-cysteine in the enantioselective addition of diethylzinc to aldehydes: loading effect and asymmetric amplification

Design of a Chiral Ionic Liquid System for the Enantioselective Addition of Diethylzinc to Aldehydes

Catálise assimétrica no Brasil: desenvolvimento e potencialidades para o avanço da indústria química brasileira

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