John C. Walton
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View article: Sulfur and Phosphorus Oxyacid Radicals
Sulfur and Phosphorus Oxyacid Radicals Open
We report a computational study of the little-studied neutral bisulfite, bisulfate, dihydro-phosphite, and dihydro-phosphate radicals (HSOx•, H2POx•, x = 3,4), calling special attention to their various tautomeric structures together with …
View article: Genesis and World Chronology
Genesis and World Chronology Open
Distrust of Genesis as history has been fostered by uniformitarian geoscience and Deep Time chronology. The reality or otherwise of a global flood has a crucial bearing on world history and chronology. Evidence of disparate kinds favouring…
View article: Genesis and World Chronology
Genesis and World Chronology Open
Distrust of Genesis as history has been fostered by uniformitarian geoscience and Deep Time chronology. The reality or otherwise of a global flood has a crucial bearing on world history and chronology. Evidence of disparate kinds favouring…
View article: Dissociations of free radicals to generate protons, electrophiles or nucleophiles: role in DNA strand breaks
Dissociations of free radicals to generate protons, electrophiles or nucleophiles: role in DNA strand breaks Open
The concept behind the research described in this article was that of marrying the ‘soft’ methods of radical generation with the effectiveness and flexibility of nucleophile/electrophile synthetic procedures.
View article: Free Radical Mediated Oxidative Degradation of Carotenes and Xanthophylls
Free Radical Mediated Oxidative Degradation of Carotenes and Xanthophylls Open
This article reviews the excited-state quenching, pro-vitamin A activity and anticarcinogenicity of carotenes and xanthophylls in relation to their chemical structures. Excited-state quenching improved with the length of the conjugated cha…
View article: EPR Studies on the Addition of Ligated Boryl Radicals to Carbonyl Compounds
EPR Studies on the Addition of Ligated Boryl Radicals to Carbonyl Compounds Open
The boron-centered radicals derived from alkenyl N-heterocyclic carbene (NHC)-boranes bearing ester substituents were recently found to ring close in 5-endo mode by addition to the oxygen atoms of the ester substituents. The inference from…
View article: Radical-Stimulated Nucleophile Release
Radical-Stimulated Nucleophile Release Open
Experimental and computational results have shown that deprotonation was enhanced for precursors containing radical centers (RED-shift). An examination of whether the inverse heterolytic dissociations that release nucleophiles instead of e…
View article: EPR and Preparative Studies of 5-<i>endo</i> Cyclizations of Radicals Derived from Alkenyl NHC-Boranes Bearing <i>tert</i>-Butyl Ester Substituents
EPR and Preparative Studies of 5-<i>endo</i> Cyclizations of Radicals Derived from Alkenyl NHC-Boranes Bearing <i>tert</i>-Butyl Ester Substituents Open
Radical H atom abstraction from a set of N-heterocyclic carbene (NHC) complexes of alkenylboranes bearing two tert-butyl ester substituents was studied by EPR spectroscopy. The initial boraallyl radical intermediates rapidly ring closed on…
View article: 5-<i>Endo</i> Cyclizations of NHC-Boraallyl Radicals Bearing Ester Substituents: Characterization of Derived 1,2-Oxaborole Radicals and Boralactones
5-<i>Endo</i> Cyclizations of NHC-Boraallyl Radicals Bearing Ester Substituents: Characterization of Derived 1,2-Oxaborole Radicals and Boralactones Open
EPR studies of radical hydrogen abstraction reactions of N-heterocyclic carbene (NHC) complexes of alkenylboranes bearing two ester substituents revealed not the expected boraallyl radicals but instead isomeric 1,2-oaxborole radicals. Such…
View article: Reflex Carbocation Release from Covalent Molecules by Endogenous Free Radicals
Reflex Carbocation Release from Covalent Molecules by Endogenous Free Radicals Open
Carbocations are pervasive in contemporary organic synthesis, so new and innocuous methods of making them are always desirable. A theoretical approach revealed that compounds in which radical generation takes place may release carbocations…
View article: Microhydration and the Enhanced Acidity of Free Radicals
Microhydration and the Enhanced Acidity of Free Radicals Open
Recent theoretical research employing a continuum solvent model predicted that radical centers would enhance the acidity (RED-shift) of certain proton-donor molecules. Microhydration studies employing a DFT method are reported here with th…
View article: Enhanced Proton Loss from Neutral Free Radicals: Toward Carbon-Centered Superacids
Enhanced Proton Loss from Neutral Free Radicals: Toward Carbon-Centered Superacids Open
Radical centers close to protons are known to enhance their dissociation. Investigation of the generality of this radical enhanced deprotonation (RED-shift) phenomenon, and the kinds of structures in which it operates, are reported. The pK…
View article: CCDC 1566656: Experimental Crystal Structure Determination
CCDC 1566656: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: CCDC 1566661: Experimental Crystal Structure Determination
CCDC 1566661: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: CCDC 1566657: Experimental Crystal Structure Determination
CCDC 1566657: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: CCDC 1566662: Experimental Crystal Structure Determination
CCDC 1566662: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: CCDC 1566658: Experimental Crystal Structure Determination
CCDC 1566658: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: CCDC 1566660: Experimental Crystal Structure Determination
CCDC 1566660: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: CCDC 1566659: Experimental Crystal Structure Determination
CCDC 1566659: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: Dealkanative Main Group Couplings across the peri-Gap
Dealkanative Main Group Couplings across the peri-Gap Open
Here, we highlight the ability of peri-substitution chemistry to promote a series of unique P-P/P-As coupling reactions, which proceed with concomitant C-H bond formation. This dealkanative reactivity represents an interesting and unexpect…
View article: Generation and Structure of Unique Boriranyl Radicals
Generation and Structure of Unique Boriranyl Radicals Open
J.C.W. thanks EaStCHEM for financial support. T.R.M. and D.P.C. thank the US National Science Foundation for grant CHE-1660927.
View article: Radical-Enhanced Acidity: Why Bicarbonate, Carboxyl, Hydroperoxyl, and Related Radicals Are So Acidic
Radical-Enhanced Acidity: Why Bicarbonate, Carboxyl, Hydroperoxyl, and Related Radicals Are So Acidic Open
Comparison of accepted pKa values of bicarbonate, carboxyl, and hydroperoxyl radicals, with those of models having the unpaired electron replaced by H atoms, implied the acidity of the radicals was greatly increased. A Density Functional T…
View article: N- to C-sulfonyl photoisomerisation of dihydropyridinones: a synthetic and mechanistic study
N- to C-sulfonyl photoisomerisation of dihydropyridinones: a synthetic and mechanistic study Open
The scope and limitations of a photoinitiated N- to C-sulfonyl migration process within a range of dihydropyridinones is assessed.
View article: Synthetic Strategies for 5- and 6-Membered Ring Azaheterocycles Facilitated by Iminyl Radicals
Synthetic Strategies for 5- and 6-Membered Ring Azaheterocycles Facilitated by Iminyl Radicals Open
The totality of chemical space is so immense that only a small fraction can ever be explored. Computational searching has indicated that bioactivity is associated with a comparatively small number of ring-containing structures. Pyrrole, in…
View article: Functionalised Oximes: Emergent Precursors for Carbon-, Nitrogen- and Oxygen-Centred Radicals
Functionalised Oximes: Emergent Precursors for Carbon-, Nitrogen- and Oxygen-Centred Radicals Open
Oxime derivatives are easily made, are non-hazardous and have long shelf lives. They contain weak N–O bonds that undergo homolytic scission, on appropriate thermal or photochemical stimulus, to initially release a pair of N- and O-centred …
View article: CCDC 962517: Experimental Crystal Structure Determination
CCDC 962517: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: CCDC 962518: Experimental Crystal Structure Determination
CCDC 962518: Experimental Crystal Structure Determination Open
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available …
View article: Bicarbonate and Alkyl Carbonate Radicals: Structural Integrity and Reactions with Lipid Components
Bicarbonate and Alkyl Carbonate Radicals: Structural Integrity and Reactions with Lipid Components Open
The elusive neutral bicarbonate radical and the carbonate radical anion form an acid/conjugate base pair. We now report experimental studies for a model of bicarbonate radical, namely, methyl carbonate (methoxycarbonyloxyl) radical, comple…
View article: Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis
Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis Open
Heterogeneous semiconductor photoredox catalysis (SCPC), particularly with TiO 2 , is evolving to provide radically new synthetic applications. In this review we describe how photoactivated SCPCs can either (i) interact with a precursor th…