Nitrile Synthesis with Aldoxime Dehydratases: A Biocatalytic Platform with Applications in Asymmetric Synthesis, Bulk Chemicals, and Biorefineries

Nitriles comprise a broad group of chemicals that are currently being industrially produced and used in fine chemicals and pharmaceuticals, as well as in bulk applications, polymer chemistry, solvents, etc. Aldoxime dehydratases catalyze the cyanide-free synthesis of nitriles starting from aldoximes under mild conditions, holding potential to become sustainable alternatives for industrial processes. Different aldoxime dehydratases accept a broad range of aldoximes with impressive high substrate loadings of up to >1 Kg L−1 and can efficiently catalyze the reaction in aqueous media as well as in non-aqueous systems, such as organic solvents and solvent-free (neat substrates). This paper provides an overview of the recent developments in this field with emphasis on strategies that may be of relevance for industry and sustainability. When possible, potential links to biorefineries and to the use of biogenic raw materials are discussed.

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Transition-Metal-Free Synthetic Strategies for the Cross-Coupling Reactions in Water: A Green Approach

Current Green Chemistry ◽

10.2174/2213346107999201006193653 ◽

2020 ◽

Vol 07 ◽

Author(s):

Tanmay Chatterjee ◽

Nilanjana Mukherjee

Keyword(s):

Transition Metal ◽

Organic Solvents ◽

Aqueous Media ◽

Cross Coupling ◽

Transition Metal Catalysts ◽

Synthetic Methods ◽

Coupling Reactions ◽

Organic Transformations ◽

Green Approach ◽

Dehydrogenative Coupling

Abstract: A natural driving force is always working behind the synthetic organic chemists towards the development of ‘green’ synthetic methodologies for the synthesis of useful classes of organic molecules having potential applications. The majority of the essential classes of organic transformations, including C-C and C-X (X = heteroatom) bond-forming crosscoupling reactions, cross dehydrogenative-coupling (CDC) mostly rely on the requirement of transition-metal catalysts and hazardous organic solvents. Hence, the scope in developing green synthetic strategies by avoiding the use of transitionmetal catalysts and hazardous organic solvents for those important and useful classes of organic transformations is very high. Hence, several attempts are made so far. Water being the most abundant, cheap, and green solvent in the world; numerous synthetic methods have been developed in an aqueous medium. In this review, the development of transitionmetal- free green synthetic strategies for various important classes of organic transformations such as C-C and C-X bondforming cross-coupling, cross dehydrogenative-coupling, and oxidative-coupling in an aqueous media is discussed.

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Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Polymers ◽

10.3390/polym12102237 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2237 ◽

Cited By ~ 2

Author(s):

P. R. Sarika ◽

Paul Nancarrow ◽

Abdulrahman Khansaheb ◽

Taleb Ibrahim

Keyword(s):

Raw Materials ◽

Phenol Formaldehyde ◽

Raw Material ◽

Wood Industry ◽

Suitable Material ◽

The Past ◽

Wide Range ◽

Recent Developments ◽

Sustainable Materials ◽

Materials Used

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.

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Electrochemical multicomponent synthesis of 4-selanylpyrazoles under catalyst- and chemical-oxidant-free conditions

Green Chemistry ◽

10.1039/d1gc00562f ◽

2021 ◽

Author(s):

Yan Wu ◽

Jin-Yang Chen ◽

Jing Ning ◽

Xue Jiang ◽

Jie Deng ◽

...

Keyword(s):

Multicomponent Reaction ◽

Raw Materials ◽

Multicomponent Synthesis ◽

Mild Conditions ◽

Simple Protocol ◽

High Yields

An electrochemical multicomponent reaction was established under catalyst-, chemical-oxidant-free and mild conditions, which provides an eco-friendly and simple protocol for constructing 4-selanylpyrazoles from easily available raw materials with high yields.

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Biocatalysis with Laccases: An Updated Overview

Catalysts ◽

10.3390/catal11010026 ◽

2020 ◽

Vol 11 (1) ◽

pp. 26

Author(s):

Ivan Bassanini ◽

Erica Elisa Ferrandi ◽

Sergio Riva ◽

Daniela Monti

Keyword(s):

Organic Synthesis ◽

Alcohol Oxidation ◽

Industrial Processes ◽

Organic Substrates ◽

Fine Chemicals ◽

Multicopper Oxidases ◽

Carbohydrate Chemistry ◽

Nucleophilic Substitutions ◽

Mediator System ◽

Integrated Processes

Laccases are multicopper oxidases, which have been widely investigated in recent decades thanks to their ability to oxidize organic substrates to the corresponding radicals while producing water at the expense of molecular oxygen. Besides their successful (bio)technological applications, for example, in textile, petrochemical, and detoxifications/bioremediations industrial processes, their synthetic potentialities for the mild and green preparation or selective modification of fine chemicals are of outstanding value in biocatalyzed organic synthesis. Accordingly, this review is focused on reporting and rationalizing some of the most recent and interesting synthetic exploitations of laccases. Applications of the so-called laccase-mediator system (LMS) for alcohol oxidation are discussed with a focus on carbohydrate chemistry and natural products modification as well as on bio- and chemo-integrated processes. The laccase-catalyzed Csp2-H bonds activation via monoelectronic oxidation is also discussed by reporting examples of enzymatic C-C and C-O radical homo- and hetero-couplings, as well as of aromatic nucleophilic substitutions of hydroquinones or quinoids. Finally, the laccase-initiated domino/cascade synthesis of valuable aromatic (hetero)cycles, elegant strategies widely documented in the literature across more than three decades, is also presented.

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Enantioselective Radical Functionalization of Imines and Iminium Intermediates via Visible Light Photoredox Catalysis

Synthesis ◽

10.1055/a-1343-6541 ◽

2020 ◽

Author(s):

Jia-Jia Zhao ◽

Hong-Hao Zhang ◽

Shouyun Yu

Keyword(s):

Visible Light ◽

Asymmetric Synthesis ◽

Carbonyl Compounds ◽

Asymmetric Reduction ◽

Chemical Transformations ◽

Photoredox Catalysis ◽

Radical Coupling ◽

Mild Conditions ◽

Iminium Ions ◽

Radical Functionalization

Visible light photoredox catalysis has recently emerged as a powerful tool for the development of new and valuable chemical transformations under mild conditions. Visible-light promoted enantioselective radical transformations of imines and iminium intermediates provide new opportunities for the asymmetric synthesis of amines and asymmetric β-functionalization of unsaturated carbonyl compounds. In this review, the advance in the catalytic asymmetric radical functionalization of imines, as well as iminium intermediates, are summarized. 1 Introduction 2 The enantioselective radical functionalization of imines 2.1 Asymmetric reduction 2.2 Asymmetric cyclization 2.3 Asymmetric addition 2.4 Asymmetric radical coupling 3 The enantioselective radical functionalization of iminium ions 3.1 Asymmetric radical alkylation 3.2 Asymmetric radical acylation 4 Conclusion

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Recent Advances in Rapid Synthesis of Non-proteinogenic Amino Acids from Proteinogenic Amino Acids Derivatives via Direct Photo-Mediated C–H Functionalization

Molecules ◽

10.3390/molecules25225270 ◽

2020 ◽

Vol 25 (22) ◽

pp. 5270

Author(s):

Zhenbo Yuan ◽

Xuanzhong Liu ◽

Changmei Liu ◽

Yan Zhang ◽

Yijian Rao

Keyword(s):

Amino Acids ◽

Direct Synthesis ◽

Environmentally Friendly ◽

Powerful Method ◽

Rapid Synthesis ◽

Conservation Of Energy ◽

Mild Conditions ◽

Recent Advances ◽

Recent Developments

Non-proteinogenic amino acids have attracted tremendous interest for their essential applications in the realm of biology and chemistry. Recently, rising C–H functionalization has been considered an alternative powerful method for the direct synthesis of non-proteinogenic amino acids. Meanwhile, photochemistry has become popular for its predominant advantages of mild conditions and conservation of energy. Therefore, C–H functionalization and photochemistry have been merged to synthesize diverse non-proteinogenic amino acids in a mild and environmentally friendly way. In this review, the recent developments in the photo-mediated C–H functionalization of proteinogenic amino acids derivatives for the rapid synthesis of versatile non-proteinogenic amino acids are presented. Moreover, postulated mechanisms are also described wherever needed.

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Recent developments in carbon dioxide utilization under mild conditions

Dalton Transactions ◽

10.1039/b920163g ◽

2010 ◽

Vol 39 (14) ◽

pp. 3347 ◽

Cited By ~ 484

Author(s):

Siti Nurhanna Riduan ◽

Yugen Zhang

Keyword(s):

Carbon Dioxide ◽

Mild Conditions ◽

Carbon Dioxide Utilization ◽

Recent Developments

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Carbon Dioxide as a Carbon Resource – Recent Trends and Perspectives

Zeitschrift für Naturforschung B ◽

10.5560/znb.2012-0219 ◽

2012 ◽

Vol 67 (10) ◽

pp. 961-975 ◽

Cited By ~ 26

Author(s):

Markus Hölscher ◽

Christoph Gürtler ◽

Wilhelm Keim ◽

Thomas E. Müller ◽

Martina Peters ◽

...

Keyword(s):

Carbon Dioxide ◽

Raw Materials ◽

Low Cost ◽

Polymeric Materials ◽

Short Review ◽

Chemical Research ◽

Bond Forming ◽

Bulk Chemicals ◽

High Thermodynamic Stability ◽

Recent Trends

With the growing perception of industrialized societies that fossil raw materials are limited resources, academic chemical research and chemical industry have started to introduce novel catalytic technologies which aim at the development of economically competitive processes relying much more strongly on the use of alternative carbon feedstocks. Great interest is given world-wide to carbon dioxide (CO2) as it is part of the global carbon cycle, nontoxic, easily available in sufficient quantities anywhere in the industrialized world, and can be managed technically with ease, and at low cost. In principle carbon dioxide can be used to generate a large variety of synthetic products ranging from bulk chemicals like methanol and formic acid, through polymeric materials, to fine chemicals like aromatic acids useful in the pharmaceutical industry. Owing to the high thermodynamic stability of CO2, the energy constraints of chemical reactions have to be carefully analyzed to select promising processes. Furthermore, the high kinetic barriers for incorporation of CO2 into C-H or C-C bond forming reactions require that any novel transformation of CO2 must inevitably be associated with a novel catalytic technology. This short review comprises a selection of the most recent academic and industrial research developments mainly with regard to innovations in CO2 chemistry in the field of homogeneous catalysis and processes.

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Iodination of insulin in aqueous and organic solvents

Biochemical Journal ◽

10.1042/bj1150011 ◽

1969 ◽

Vol 115 (1) ◽

pp. 11-18 ◽

Cited By ~ 24

Author(s):

A. Massaglia ◽

U. Rosa ◽

G. Rialdi ◽

C. A. Rossi

Keyword(s):

Ethylene Glycol ◽

Organic Solvents ◽

Molecular Conformation ◽

Aqueous Media ◽

Native Structure ◽

Experimental Conditions ◽

Polar Environment ◽

Polar Area ◽

The Difference ◽

A Chain

1. The iodination of insulin was studied under various experimental conditions in aqueous media and in some organic solvents, by measuring separately the uptake of iodine by the four tyrosyl groups and the relative amounts of monoiodotyrosine and di-iodotyrosine that are formed. In aqueous media from pH1 to pH9 the iodination occurs predominantly on the tyrosyl groups of the A chain. Some organic solvents increase the iodine uptake of the B-chain tyrosyl groups. Their efficacy in promoting iodination of Tyr-B-16 and Tyr-B-26 is in the order: ethylene glycol and propylene glycol≃methanol and ethanol>dioxan>8m-urea. 2. It is suggested that each of the four tyrosyl groups in insulin has a different environment: Tyr-A-14 is fully exposed to the solvent; Tyr-A-19 is sterically influenced by the environmental structure, possibly by the vicinity of a disulphide interchain bond; Tyr-B-16 is embedded into a non-polar area whose stability is virtually independent of the molecular conformation; Tyr-B-26 is probably in a situation similar to Tyr-B-16 with the difference that its non-polar environment depends on the preservation of the native structure.

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