Metal- and Oxidant-Free Photoinduced Aromatic Trifluoromethylation Performed in Aerated Gel Media: Determining the Effects on Yield and Selectivity

Abramov, Alex; Vernickel, Hendrick; Saldías, César; Díaz, David Díaz

doi:10.3390/molecules24010029

Cited by 9 publications

(8 citation statements)

References 28 publications

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“…Polyamide‐based supramolecular gels were also applied as reaction media to carry out air‐sensitive and metal‐free, light‐induced trifluoromethylation of six‐membered (hetero)arenes under aerobic conditions (Scheme 36). [48] The reaction was performed at room temperature using sodium triflinate as a source of radicals and diacetyl as electron donor. It was observed that different variables influenced the yields and selectivity of the reaction, especially the type of gelator and its concentration.…”

Section: Photocatalysismentioning

confidence: 99%

Catalysis in Supramolecular Systems: the Case of Gel Phases

et al. 2021

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Dedicated to Prof. Franco Cozzi in the occasion of his 70th birthday.Supramolecular gels are a fascinating class of materials, originated by the self-assembly of low molecular weight molecules. Underpinned by non-covalent interactions, they find application in a diverse range of fields. Among these, supramolecular gels can be considered as organized, nonconventional reaction media, able to influence reactivity in a radically different way, compared with what happens in solution. This short review will focus on this aspect, covering literature from 2010 onwards, addressing the application of supramolecular gels as reaction media. In particular, in the first section we explore organocatalytic reactions in gel phase, with wide synthetic relevance, such as aldol and Mannich reactions as well as Friedel Crafts or ester hydrolysis processes. Subsequently, focus is laid on metal-catalysed reactions, among which relevance is given to widely used reactions like crosscoupling and click reactions. Then, the final sections describe the use of supramolecular gels as reaction media for photoand biocatalysed processes.

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Section: Photocatalysismentioning

confidence: 99%

Catalysis in Supramolecular Systems: the Case of Gel Phases

et al. 2021

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“…We have recently described our preliminary results regarding a similar trifluoromethylation reaction of unactivated six-membered (hetero)arenes under aerobic conditions using supramolecular gels as confining media. 48 When the reaction was performed under inert atmosphere conditions with vigorous stirring, the overall yield was 96% favoring the monosubstituted product (i.e., monosubstituted 79%, disubstituted 17%, Figure 13). The overall yield decreased to only 37% when the reaction was carried out under aerobic conditions.…”

Section: ■ Photoreductionmentioning

confidence: 96%

The Prospect of Photochemical Reactions in Confined Gel Media

et al. 2019

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Conspectus Nature is intrinsically able to control kinetics, conversion, and selectivity of biochemical processes by means of confined reaction environments such as enzyme pockets, bilayer membranes, micelles, vesicles, cells, or bioorganic frameworks. The main reason for this fact is the optimal molecular alignment and restricted motion of reactant molecules compared to those found in bulk solution. Under this inspiration, a number of synthetic photo-nanoreactors based on supramolecular self-assembled systems have been developed during the last decades, including mesoporous inorganic materials, microemulsions, micelles, vesicles, lipid bilayer foams, polyelectrolyte nanoparticles, etc. In a broader sense, nanoreactor technology constitutes nowadays a promising tool to enhance organic synthesis under sustainable reaction conditions. In general, nanoreactors change the essential properties of the molecules within them, thus affecting their chemical reactivity. Among the nanoreactor-like systems described in the literature to facilitate photochemical processes, the more recent use of viscoelastic supramolecular gels, typically made of low-molecular-weight (LMW) compounds self-assembled through noncovalent interactions, as compartmentalized reaction media is particularly appealing due to the versatility of these materials in terms of fabrication, properties, and processability. Furthermore, the high specific surface areas found in supramolecular gels, their stimuli-responsive reversibility, good diffusion properties enhancing the interactions between reactants and the three-dimensional (3D) porous network, functional tunability, and blocking effect of external oxygen are some of the most important features that can benefit photoinduced processes carried out in confined gel media. Not surprisingly, the efficiency of photochemical processes inside gel media is largely dependent on the type of reaction, characteristics of the gel network, solvent nature, reactant properties, and reaction conditions. Thus, the main focus of this Account is to provide a concise overview of the most relevant examples reported by us and others in order to illustrate the main advantages associated with the emerging use of gel-based materials as nonconventional reaction media to facilitate and control photochemical reactions. In particular, photodimerization, triplet–triplet annihilation upconversion (TTA-UC) coupled to single electron transfer (SET), photooxidation, photoreduction, and trifluoromethylation reactions will be illustrated during the discussion. These examples suggest that gel-based media can provide a versatile platform for the discovery of new reaction pathways and facilitate the way that photochemical reactions are traditionally carried out in academia and industry in terms of reaction conditions and required infrastructure. In addition, the use of physical or chemical gels as reaction systems may also accelerate high-throughput screening of photocatalysts. Overall, a judicious choice of gelators, reactants, solvent, and rea...

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“…Thus, it can be comfortably argued that photoredox catalysis processes in supramolecular gels can emerge as an advanced methodology for the synthesis of halogenated drug molecules under aerobic conditions. 130 In a recent report, Yang et al demonstrated multicomponent supramolecular gels from two types of porphyrin dyes, TCPP/ THPP and an L-glutamic acid based amide gelator (G4) (Figure 29). 131 J-aggregation of porphyrin derivatives and protonation under neutral conditions within DFM gels led to enhanced absorption in visible wavelengths.…”

Section: Photoredox Catalysis Processes Withinmentioning

confidence: 99%

“…The gel network decreased the diffusion of O 2 , preventing fast deactivation of the excited species generated upon photoexcitation of the catalyst. Thus, it can be comfortably argued that photoredox catalysis processes in supramolecular gels can emerge as an advanced methodology for the synthesis of halogenated drug molecules under aerobic conditions …”

Section: Photoredox Catalysis Processes Within Supramolecular Gel Net...mentioning

confidence: 99%

Supramolecular Engineering and Self-Assembly Strategies in Photoredox Catalysis

2020

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Visible-light-mediated photoredox catalysis has evolved as an efficient and mild alternative to conventional organic synthesis. Inspired by the elegance and sophistication of natural photosynthetic machinery involving complex self-assembled systems, recently researchers have resorted to the implementation of supramolecular chemistry in photoredox catalytic processes with the objective of achieving improved efficiency for known chemical reactions, as well as developing advanced methodologies for inaccessible transformations. Supramolecular engineering offers the ability to customize the existing properties of traditional photoredox catalysts by various self-assembly strategies and expands their scope in cutting-edge synthetic methodologies by means of their noncovalent interactions with different chemical components. In this review, we summarize the recent advances and key achievements in photoredox catalytic synthesis adopting various supramolecular techniques based on organic self-assembled systems and underline their advantages and mechanistic facets. Diverse directional noncovalent interaction driven photoredox catalytic systems are thoroughly discussed. Furthermore, self-assembly strategies for various photocatalytic reactions within confined nanospaces (viz. micelles, vesicles, polymersomes, polymeric nanoparticles, gels etc.) are summarized. Finally, a brief perspective on the encouraging future prospects and challenges in this contemporary field of supramolecular photoredox catalysis is presented.

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Metal- and Oxidant-Free Photoinduced Aromatic Trifluoromethylation Performed in Aerated Gel Media: Determining the Effects on Yield and Selectivity

Cited by 9 publications

References 28 publications

Catalysis in Supramolecular Systems: the Case of Gel Phases

Catalysis in Supramolecular Systems: the Case of Gel Phases

The Prospect of Photochemical Reactions in Confined Gel Media

Supramolecular Engineering and Self-Assembly Strategies in Photoredox Catalysis

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