scholarly journals Aldehydes as powerful initiators for photochemical transformations

2020 ◽  
Vol 16 ◽  
pp. 833-857 ◽  
Author(s):  
Maria A Theodoropoulou ◽  
Nikolaos F Nikitas ◽  
Christoforos G Kokotos
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Organic Molecules ◽  
Photophysical Properties ◽  
Organic Transformations ◽  
Aliphatic Aldehydes ◽  
Small Organic Molecules ◽  
Photochemical Transformations ◽  
The Way

Photochemistry, the use of light to promote organic transformations, has been known for more than a century but only recently has revolutionized the way modern chemists are thinking. Except from transition metal-based complexes, small organic molecules have been introduced as catalysts or initiators. In this review, we summarize the potential that (aromatic or aliphatic) aldehydes have as photoinitiators. The photophysical properties and photoreactivity of benzaldehyde are initially provided, followed by applications of aldehydes as initiators for polymerization reactions. Finally, the applications to date regarding aldehydes as photoinitiators in organic synthesis are presented.

scholarly journals Transition metal–assisted carbonization of small organic molecules toward functional carbon materials

2018 ◽  
Vol 4 (7) ◽  
pp. eaat0788 ◽  
Author(s):  
Zhen-Yu Wu ◽  
Shi-Long Xu ◽  
Qiang-Qiang Yan ◽  
Zhi-Qin Chen ◽  
Yan-Wei Ding ◽  
...  
Keyword(s):  
Transition Metal ◽  
Organic Molecules ◽  
Carbon Materials ◽  
Small Organic Molecules

Microwave-assisted organo-catalyzed C-C and C-X (heteroatom) bond-forming reactions-An overview

2021 ◽  
Vol 08 ◽  
Author(s):  
Kantharaju Kamanna ◽  
Yamanappagouda Amaregouda
Keyword(s):  
Organic Molecules ◽  
Organic Transformations ◽  
Large Area ◽  
High Demand ◽  
Moisture Sensitivity ◽  
Small Organic Molecules ◽  
Bond Forming ◽  
Direct Benefits ◽  
Speed Up ◽  
Chemical Manufacture

: Organocatalysis defines small organic molecules exclusively containing carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorous atom to speed-up the chemical reactions. Researcher demonstrated large area of applications in various organic transformations catalyzed by the organocatalysts, due to their less moisture sensitivity and air, easy abundance, less polluting, not interfere with the final product and inexpensive. This highlights high demand and direct benefits in the pharmaceutical intermediate and fine chemical manufacture compared to other conventional transition metal and enzyme catalysts. This review article intends to compile literature reported application of the microwave accelerated organocatalyzed carbon-carbon and carbon–heteroatom bond formation reactions reported in the literature.

Pyridine-mediated B-B Bond Activation of (RO)2B-B(OR)2 for Generating Borylpyridine Anions and Pyridine-stabilized Boryl Radicals as Useful Boryl Reagents in Organic Synthesis

Synthesis ◽  
2021 ◽  
Author(s):  
Luis Carlos Misal Castro ◽  
Ibrahim Sultan ◽  
Hayato Tsurugi ◽  
Kazushi Mashima
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Pyridine Derivatives ◽  
Organic Transformations ◽  
Lewis Bases ◽  
Metal Free ◽  
Synthetic Utility

Significant developments have been achieved in recent years toward the utilization of (RO)2B-B(OR)2 for exploring transition metal-free organic transformations in organic synthesis. Among the various combinations of Lewis bases with diborons developed so far, pyridine-derivatives are simple, commercially available, and cheap compounds to expand the synthetic utility of diborons by generating borylpyridine anions and pyridine-stabilized boryl radicals via the B-B bond cleavage. These borylpyridine species mediate a series of transformations in both a catalytic and stoichiometric manner for C-X activation (X = Halogen, CO2H, NR2) and concomitant C-borylation, hydroboration, C-C bond formation, and reduction reactions.

scholarly journals Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments

2015 ◽  
Author(s):  
Chiara Palumbo
Keyword(s):  
Asymmetric Catalysis ◽  
Scientific Community ◽  
Organic Molecules ◽  
Optically Active ◽  
Enantioselective Synthesis ◽  
Fine Chemicals ◽  
Organic Transformations ◽  
Small Organic Molecules ◽  
Substrate Activation ◽  
High Yields

Organocatalysis, that is the use of small organic molecules to catalyse organic transformations, has been included among the most successful concepts in asymmetric catalysis and it has been used for the enantioselective construction of C-C, C-N, C-O, C-S, C-P, and C-halide bonds. Since the seminal works in early 2000, the scientific community has been paying an ever-growing attention to the use of organocatalysts for the synthesis, with high yields and remarkable stereoselectivities, of optically active fine chemicals of interest for the pharmaceutical industry. A brief overview is here presented about the two main classes of substrate activation by the catalyst: covalent organocatalysis and non-covalent organocatalysis, with a more stringent focus on some recent outcomes in the field of the latter and of hydrogen-bond-based catalysis. Finally, some successful examples of heterogenisation of organocatalysts are also discussed, in the view of a potential industrial exploitation.

scholarly journals Heterogeneous photocatalysis in flow chemical reactors

2020 ◽  
Vol 16 ◽  
pp. 1495-1549 ◽  
Author(s):  
Christopher G Thomson ◽  
Ai-Lan Lee ◽  
Filipe Vilela
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Continuous Flow ◽  
Environmental Remediation ◽  
Photophysical Properties ◽  
Heterogeneous Photocatalysis ◽  
Attractive Alternative ◽  
Redox Potentials ◽  
Separation And Purification ◽  
Chemical Reactors

The synergy between photocatalysis and continuous flow chemical reactors has shifted the paradigms of photochemistry, opening new avenues of research with safer and scalable processes that can be readily implemented in academia and industry. Current state-of-the-art photocatalysts are homogeneous transition metal complexes that have favourable photophysical properties, wide electrochemical redox potentials, and photostability. However, these photocatalysts present serious drawbacks, such as toxicity, limited availability, and the overall cost of rare transition metal elements. This reduces their long-term viability, especially at an industrial scale. Heterogeneous photocatalysts (HPCats) are an attractive alternative, as the requirement for the separation and purification is largely removed, but typically at the cost of efficiency. Flow chemical reactors can, to a large extent, mitigate the loss in efficiency through reactor designs that enhance mass transport and irradiation. Herein, we review some important developments of heterogeneous photocatalytic materials and their application in flow reactors for sustainable organic synthesis. Further, the application of continuous flow heterogeneous photocatalysis in environmental remediation is briefly discussed to present some interesting reactor designs that could be implemented to enhance organic synthesis.

Organocatalytic Synthesis of Heterocycles: A Brief Overview Covering Recent Aspects

2020 ◽  
Vol 07 ◽  
Author(s):  
Rajib Sarkar ◽  
Chhanda Mukhopadhyay
Keyword(s):  
Organic Synthesis ◽  
Organic Molecules ◽  
Synthetic Methods ◽  
Environmentally Benign ◽  
Reaction Conditions ◽  
Small Organic Molecules ◽  
Heterocycle Synthesis ◽  
The Past ◽  
Metal Catalyzed ◽  
Atom Bond

Abstract:: The use of small organic molecules as organocatalysts in organic synthesis has intensely studied over the past decade. In this emerging field, considerable study has led to the introduction of various efficient organocatalyzed synthetic methods of carbon-carbon and carbon-hetero atom bond formations. The use of these organocatalysts also emerged environmentally benign reaction conditions compared to the metal catalyzed transformations. In this review, we make a special attention on the most recent organocatalytic protocols reported for the synthesis of heterocycles. The works have been outlined by depending on the organocatalysts used as (i) nitrogen based molecules as organocatalyst, (ii) NHCs as organocatalyst, and (iii) phosphorus based molecules as organocatalyst. The discussion intends to reveal the scope as well as vitality of organocatalysis in the area of heterocycle synthesis.

scholarly journals Small organic molecules with tailored structures: initiators in the transition-metal-free C–H arylation of unactivated arenes

RSC Advances ◽  
2020 ◽  
Vol 10 (25) ◽  
pp. 14500-14509 ◽  
Author(s):  
Zhenghui Liu ◽  
Peng Wang ◽  
Yu Chen ◽  
Zhenzhong Yan ◽  
Suqing Chen ◽  
...  
Keyword(s):  
Transition Metal ◽  
Organic Molecule ◽  
Organic Molecules ◽  
Efficient Synthesis ◽  
Small Organic Molecules ◽  
Small Organic Molecule ◽  
Metal Free ◽  
Aryl Iodides

A small organic molecule was tailored for the efficient synthesis of biphenyl and its derivatives from aryl iodides.

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