From Immobilization to Catalyst Use: A Complete Continuous‐Flow Approach Towards the Use of Immobilized Organocatalysts

Oliveira, Pedro Henrique Ramos de; Santos, Bruno Maia da Silva; Leão, Raquel A. C.; Miranda, Leandro S. M.; Gil, Rosane A. S. San; Souza, Rodrigo O. M. A. de; Finelli, Fernanda G.

doi:10.1002/cctc.201901129

Cited by 19 publications

(8 citation statements)

References 34 publications

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“…In 2019, Oliveira reported the immobilization of MacMillan catalyst supported on silica under continuous flow conditions [57] . The authors compared the activity of the catalyst immobilized on silica gel 52 under continuous flow conditions, and under batch conditions for the Diels‐Alder reaction.…”

Section: Introductionmentioning

confidence: 99%

Recent Development of Recoverable MacMillan Catalyst in Asymmetric Organic Transformations

Deepa

Singh

2020

Adv Synth Catal

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Chiral imidazolidinone as an organocatalyst was developed by MacMillan and co‐workers in 2000 and they evaluated this organocatalyst originally in the enantioselective Diels‐Alder reaction. Later, this catalyst was used in a number of other asymmetric organic transformations. Chiral organocatalysts are expensive, therefore their recoverability and reusability are highly desirable to make the organic transformation economically viable for industrial application. Hence, the chiral imidazolidinone was modified and attached to different supports for its recoverability and reusability. A number of recoverable imidazolidinones have been reported in asymmetric Diels‐Alder reactions. In this review, we have summarized the reports on reusable and recoverable imidazolidinones (MacMillan catalysts) as organocatalysts in asymmetric organic transformations.magnified image

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Section: Introductionmentioning

confidence: 99%

Recent Development of Recoverable MacMillan Catalyst in Asymmetric Organic Transformations

Deepa

Singh

2020

Adv Synth Catal

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“…To solve the problem of the rapid deactivation of catalysts in heterogeneous asymmetric reactions, Finellia nd co-workers were the first to report the synthesis and immobilization of organo-catalysts under batch andc ontinuous-flow conditions. [27] The first-generation MacMillan's organocatalyst was easily synthesized from l-phenylalanine 79 and immobilized on silica through ac arbamate linkage by using batch and flow systems( Figure 25). The performance of theses ilica-supported organocatalysts 80 was investigatedi nt he Diels-Alder reaction between cyclopentadiene and E-cinnamaldehyde.…”

Section: Multi-step Continuous-flow Synthesis Using Supported Synthetmentioning

confidence: 99%

Multi‐Step Continuous‐Flow Organic Synthesis: Opportunities and Challenges

Jiao

Nie

et al. 2021

Chemistry A European J

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Continuous‐flow multi‐step synthesis takes the advantages of microchannel flow chemistry and may transform the conventional multi‐step organic synthesis by using integrated synthetic systems. To realize the goal, however, innovative chemical methods and techniques are urgently required to meet the significant remaining challenges. In the past few years, by using green reactions, telescoped chemical design, and/or novel in‐line separation techniques, major and rapid advancement has been made in this direction. This minireview summarizes the most recent reports (2017–2020) on continuous‐flow synthesis of functional molecules. Notably, several complex active pharmaceutical ingredients (APIs) have been prepared by the continuous‐flow approach. Key technologies to the successes and remaining challenges are discussed. These results exemplified the feasibility of using modern continuous‐flow chemistry for complex synthetic targets, and bode well for the future development of integrated, automated artificial synthetic systems.

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“…In 2013 Cozzi and Benaglia reported the continuous-flow stereoselective organocatalyzed Diels Alder reactions in a chiral catalytic "homemade" HPLC column [65]; the silica-supported MacMillan imidazolidinone 44 was packed into an empty stainless steel HPLC column and used to efficiently promote stereoselective Diels-Alder reactions on different substrates for more than 150 h of continuous operation [66]. Finelli et al [67] reported the in-flow preparation of the first-generation MacMillan's organocatalyst immobilized onto silica through a carbamate linkage (Figure 12). Their synthesis started from the esterification of L-phenylalanine 45 that was carried out at 50 °C in a 3 mL coil (1 hour residence time) in 90% yield, followed by the formation of the corresponding ethanolamide 46 at 60 °C, (3 mL coil, 1 hour residence time, 90% yield).…”

Section: Packed-bed Reactorsmentioning

confidence: 99%

Stereoselective organocatalysis and flow chemistry

Puglisi

Rossi

2021

Physical Sciences Reviews

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Organic synthesis has traditionally been performed in batch. Continuous-flow chemistry was recently rediscovered as an enabling technology to be applied to the synthesis of organic molecules. Organocatalysis is a well-established methodology, especially for the preparation of enantioenriched compounds. In this chapter we discuss the use of chiral organocatalysts in continuous flow. After the classification of the different types of catalytic reactors, in Section 2, each class will be discussed with the most recent and significant examples reported in the literature. In Section 3 we discuss homogeneous stereoselective reactions in flow, with a look at the stereoselective organophotoredox transformations in flow. This research topic is emerging as one of the most powerful method to prepare enantioenriched products with structures that would otherwise be challenging to make. Section 4 describes the use of supported organocatalysts in flow chemistry. Part of the discussion will be devoted to the choice of the support. Examples of packed-bed, monolithic and inner-wall functionalized reactors will be introduced and discussed. We hope to give an overview of the potentialities of the combination of (supported) chiral organocatalysts and flow chemistry.

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From Immobilization to Catalyst Use: A Complete Continuous‐Flow Approach Towards the Use of Immobilized Organocatalysts

Cited by 19 publications

References 34 publications

Recent Development of Recoverable MacMillan Catalyst in Asymmetric Organic Transformations

Recent Development of Recoverable MacMillan Catalyst in Asymmetric Organic Transformations

Multi‐Step Continuous‐Flow Organic Synthesis: Opportunities and Challenges

Stereoselective organocatalysis and flow chemistry

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