Inorganic Radicals in Organic Synthesis
29
Citation
51
Reference
10
Related Paper
Citation Trend
Abstract:
Inorganic radicals have so far led a shadowy existence in synthetic organic radical chemistry. This article briefly reviews the synthetic applications of the most important inorganic radicals. In addition, a new synthetic concept is presented, which should demonstrate that with inorganic, oxygen-centered radicals of the type X-O*, in which X is NO2, SO3-, and H, respectively, novel oxidative radical reactions could be performed, which in turn are difficult or impossible with their organic counterparts, the alkoxyl radicals R-O*.Keywords:
Organic Synthesis
Alkoxy radicals have been identified as versatile intermediates in synthetic chemistry in the last few decades. Over the last decade, various catalytic processes for the in situ generation of alkoxy radicals have been explored, leading to the development of new synthetic methodologies based on alkoxy radicals. In this review, we provided a comprehensive review of recent developments in the utilization of alkoxy radicals in diverse organic transformations, natural product synthesis, and the late-stage modification of bioactive molecules through the implementation of the photoredox methodology.
Organic Synthesis
Cite
Citations (2)
Cite
Citations (15)
Abstract Exchange of Alkoxy Into Cyano Group by Means of Cyanotrimethylsilane.
Cite
Citations (0)
Inorganic radicals have so far led a shadowy existence in synthetic organic radical chemistry. This article briefly reviews the synthetic applications of the most important inorganic radicals. In addition, a new synthetic concept is presented, which should demonstrate that with inorganic, oxygen-centered radicals of the type X-O*, in which X is NO2, SO3-, and H, respectively, novel oxidative radical reactions could be performed, which in turn are difficult or impossible with their organic counterparts, the alkoxyl radicals R-O*.
Organic Synthesis
Cite
Citations (29)
Cite
Citations (7)
Abstract Until recently, repetitive solid‐phase synthesis procedures were used predominantly for the preparation of oligomers such as peptides, oligosaccharides, peptoids, oligocarbamates, peptide vinylogues, oligomers of pyrrolin‐4‐one, peptide phosphates, and peptide nucleic acids. However, the oligomers thus produced have a limited range of possible backbone structures due to the restricted number of building blocks and synthetic techniques available. Biologically active compounds of this type are generally not suitable as therapeutic agents but can serve as lead structures for optimization. “Combinatorial organic synthesis” has been developed with the aim of obtaining low molecular weight compounds by pathways other than those of oligomer synthesis. This concept was first described in 1971 by Ugi. [56f,g,59c] Combinatorial synthesis offers new strategies for preparing diverse molecules, which can then be screened to provide lead structures. Combinatorial chemistry is compatible with both solution‐phase and solid‐phase synthesis. Moreover, this approach is conducive to automation, as proven by recent successes in the synthesis of peptide libraries. These developments have led to a renaissance in solid‐phase organic synthesis (SPOS), which has been in use since the 1970s. Fully automated combinatorial chemistry relies not only on the testing and optimization of known chemical reactions on solid supports, but also on the development of highly efficient techniques for simultaneous multiple syntheses. Almost all of the standard reactions in organic chemistry can be carried out using suitable supports, anchors, and protecting groups with all the advantages of solid‐phase synthesis, which until now have been exploited only sporadically by synthetic organic chemists. Among the reported organic reactions developed on solid supports are Diels–Alder reactions, 1,3‐dipolar cycloadditions, Wittig and Wittig–Horner reactions, Michael additions, oxidations, reductions, and Pd‐catalyzed CC bond formation. In this article we present a comprehensive review of the previously published solid‐phase syntheses of nonpeptidic organic compounds.
Solid-Phase Synthesis
Organic Synthesis
Peptide Synthesis
Oligomer
Combinatorial synthesis
Cite
Citations (646)
This chapter contains sections titled: C-, N-, and O-centered Radicals Si-, P-, and S-centered Radicals CC-, NN-, and OO-centered Radicals NO- and NO2-centered Radicals PO-, PP-, SO-, SS-, and SO2-centered Radicals
Cite
Citations (4)
Abstract The kinetics and mechanism of the photochemical reactions of the peroxide radicals have been investigated in polytetrafluorethylene by electron paramagnetic resonance. Under irradiation by UV light, with λ < 300 nm, the peroxide radicals ˜CF 2 CF(O 2 )CF 2 ∼ and ∼CF 2 CF 2 O 2 are dissociated and the end fluoralkyl radicals ∼CF 2 CF 2 are produced. The activation effective energy of the photodissociation of the peroxide radicals is equal to approximately 1‐2 kcal/mole. Quantum yield of the dissociation of peroxide radicals is equal to about 1. In the presence of oxygen the photorecombination of the peroxide radicals takes place. The photorecombination of the peroxide radicals bring about a reversal of the reactions of the dissociation of the end peroxide radicals and the addition of oxygen to the end fluoralkyl radical. Due to a dependence upon the initial concentration of peroxide radicals, the quantity of molecules of CF 2 O produced varies from 25 to 45 per one vanished radical. The rate of the photorecombination of the peroxide radical is in linear dependence on light intensity and in the interval 150‐500 torr does not depend upon oxygen pressure.
Peroxide
Organic peroxide
Cite
Citations (7)
Photodegradation
Hydroxyl radical
Cite
Citations (41)
This chapter contains sections titled: Introduction Formation of Phenoxyl Radicals Oxidation of Phenols by Metal Ions Oxidation of Phenols by Free Radicals Oxidation of Phenols by Radical Cations Reaction of Phenols with Hydroxyl Radicals. The Addition/Elimination Mechanism Formation of Phenoxyl Radicals by Oxidative Replacement of Substituents Formation of Phenoxyl Radicals by Intramolecular Electron Transfer Formation of Phenoxyl Radicals from Phenols and Hydroxyphenols by Reaction with O2 and/or O2·− (Autoxidation) Properties of Phenoxyl Radicals Electron Spin Resonance Spectra of Phenoxyl Radicals Phenoxyl and Monosubstituted Phenoxyl Radicals Phenoxyl Radicals with Extended π-systems Kinetic ESR Measurements Comparison with Isoelectronic Radicals Optical Spectra of Phenoxyl Radicals Acid–Base Equilibria of Phenoxyl Radicals Reactions of Phenoxyl Radicals Reduction Potentials of Phenoxyl Radicals References
Autoxidation
Cite
Citations (46)