Themed collection Free Radical Chemistry special themed issue in memory of Athel Beckwith

Relative enthalpy changes for the two possible modes of ring opening of 2,2-dimethylcyclopropylcarbinyl radical. Tunnelling is indicated by wavy lines.

Sulfonyl radicals generate from sulfonylhydrazides in the presence of an iron catalyst and air. Addition of resultant radicals to alkenes affords β-hydroxysulfones in good yield.

Direct generation of a benzyl radical by C–H bond activation of toluenes and the addition reaction were developed.

Atom efficient generation of Sm(OTf)₂ in acetonitrile provides a stable alternative to SmI₂.

Further investigations into the direct synthesis of N-nororipavine from oripavine using iron powder under non-classical Polonovski conditions have been conducted. The stoichiometry, solvents and iron oxidation rates were found to have a dramatic effect on the rate of N-demethylation as well as product yield. Herein, we also present high-yield access to the N-demethylated product simply by employing stainless steel rather than iron powder as redox catalyst.

Stable chlorine atom complexes with lignin derivatives may mediate reaction of chlorine atom in the environment and in bleaching facilities.

Vinyl compounds can be transformed to macro-RAFT agents by RAFT single unit monomer insertion providing a route to block copolymers with a short, non-hydrolysable block linkage.

Radical alkylation of a chiral equivalent of glycolic acid occurs with good to high diastereoselectivity that compares favorably with the corresponding enolate alkylation.

Isomeric radicals of the model peptide Bz-Ala-Gly-OMe can be distinguished via gas phase ion-molecule reactions with O₂ and NO₂˙. The latter reagent acts as a radical trap to give nitrate esters, whose structures can be distinguished via collision induced dissociation

What are the factors that influence the effect of substituents on the stability of multiply substituted carbon-centered radicals? This question is addressed with the help of a variety of existing and new thermochemical quantities.

The free-radical copolymerization of alkyl-substituted 1,3-butadienes with sulfur dioxide produced poly(diene sulfone)s consisting of a highly alternating and 1,4-regiospecific repeating structure.

One-pot multicomponent domino radical synthesis of aminoalcohols under mild conditions.

Efficient methods for the synthesis of α-methylene lactams were developed based on radical carbonylation and cyclization of ω-alkynylamines.

The photochemical cyclization of o-alkynylaryl isocyanides with (RSe)₂, (RTe)₂, RSH, RSeH, R₃GeH, and TTMSS provides a useful tool to access quinoline derivatives.

Vitamin C lipid-soluble derivatives react with peroxyl radicals at close to diffusion-controlled rate in the dissociated form which has a BDE(OH) lower by 10 kcal mol⁻¹ than the neutral form.

Replacement of (S)-tyrosine by a novel peptide building block led to a high subtype selectivity for the human NTS2 receptor.

Elaboration of the C10–C20 skeleton of gymnodimine, incorporating a tetrahydrofuran fragment, has been performed through a stereocontrolled Ueno–Stork radical cyclization.

Experimental evidence and computational results suggest that the thermal C²–C⁶/[2 + 2] cyclisation of enyne-allenes follows a stepwise mechanism involving the reversible formation of the C²–C⁶ diradical.

The role of structural effects on the intrinsic ET reactivities of short-lived N-oxyl radicals have been examined through a kinetic study of the one electron oxidation reactions of substituted ferrocenes

Radical 5-exo-dig cyclization is used as an entry to bis-butyrolactone natural products with L-ara configuration.

N,N-Dialkoxyamides — unusual anomeric amides. A new PIFA mediated synthesis and studies of their radical homolysis under thermal conditions.

In the presence of pyridine, phenol oxidation occurs concertedly with proton transfer, the charge being delocalized over a primary shell of water molecules bound to the pyridinium cation.

A new mechanism of free radical reactions of artemisinin and its analogs is proposed, where the initiation of hydroxy radicals plays a key role in the antimalarial effect.

The first example of paramagnetic rotaxane containing cucurbit[6]urils has been reported.

The search for photosensitive alkoxyamines remains a challenge. We investigate the effect of alkoxyamine structure on the photodissociation process.

BHandHLYP/6-311++G(d,p) calculations predict that intramolecular homolytic substitution by aryl radicals at the sulfur atom in phenylsulfinates and sulfinamides competes with intramolecular addition to the phenyl ring.

The addition of α-hydroxyalkyl radicals to 8-bromoguanine derivatives results in the efficient formation of intermolecular C–C bonds in aqueous media.

Copper-mediated Fenton oxidation of 2′-deoxyguanosine leads to predominant formation of 5-carboxamido-5-formamido-2-iminohydantoin (d2Ih) via C5 hydroxylation.

Upon association of quinolones to template (+)-1 the chirality information is provided for the enantioselectivity determining cyclisation step.

A biomimetic model offers for the first time the parallel estimation of peroxidation and isomerization as results of oxidative free radical conditions in the presence of thiols.

The ease with which plant-derived thiosulfinates undergo Cope elimination to form the corresponding sulfenic acids accounts for their differences in antioxidant activity.

Many density-functional theory methods provide poor agreement to experimental rate constants for the ring opening of radical clock species.

Interception of alkyl radicals leads to fragmentation, detected by release of alcohols.

The formation of radicals upon high energy irradiation of sutures allows their easy GMA-derivatization.

Imidoyl and thioyl radicals add to the nitrogen of methanimine through simultaneous multi-orbital interactions between the radicals and the imine.

Cis- and trans-decalins, trans-perhydroazulenes, and [5.3.1]bicyclo-undecanone scaffolds can be readily constructed starting from unsaturated ketones and using the degenerative xanthate transfer technology to accomplish unusual and otherwise difficult radical cyclisations

Damage of aromatic amino acids by the most important atmospheric free-radical oxidant, NO₃˙, was studied under simulated environmental conditions.

Stable, readily available, low molecular weight N-hetereocyclic carbene boranes reduce halides bearing electron withdrawing substituents. Product isolation is convenient.

The synthesis, characterization and studies on aggregation behavior by DLS and AFM of various peptide–polymer conjugates synthesized by NMP are described.

Cyclic, peri- and benzo-fused N,N-bissulfonylnitroxides undergo hydrogen atom abstraction in preference to fragmentation.

A route to cis–hydrindanes, featuring SmI₂-mediated cyclisations, has been used in an RCM approach to analogues of the antibacterial pleuromutilin.

Spin trapping of peroxyl radicals using DEPMPO as the spin trap

Rate constant data and Arrhenius parameters have been determined for a series of substituted hexenyl radicals of differing electronic and steric demand. Rate constants (k_cis + k_trans) were found to lie in the range 0.4–2.1 × 10⁵ s⁻¹ at 25°. Cis/trans and k_c/k_H ratios were found to be solvent dependent.

The dynamics of β-elimination for retinol thiyl addition radicals and their reactions with oxygen were examined for the first time.

The propagation step of Bolland and Gee's basic autooxidation scheme is not actually thermodynamically favoured for many polymers and biopolymers.

Rate constants for 5-exo and 6-exo cyclizations of α-hydroxy radicals were measured.

Homolytic addition/substitution chemistry has been used to prepare benzoselenophene analogues of the antihypertensive compounds milfasartan and eprosartan. Benzothiophenes were also prepared.

Chemoenzymatic dynamic kinetic resolution of amines involving sulfanyl radical-induced racemization happened to be the very first switchable DKR process allowing the synthesis of either (R)- or (S)-amides.