Oxidative azidations of phenols and ketones using iodine azide after release from an ion exchange resin

α-Cleavage of 2,2-Diazido-2,3-dihydroinden-1-one in Solution and Cryogenic Matrices

The Norrish type I (α-cleavage) reaction is an excellent photochemical method for radical-pair formation in solution. However, in cryogenic matrices, the starting material typically re-forms before the radical pair diffuses apart. This study focused on N2 extrusion from an azido alkyl radical to prevent radical-pair recombination. Irradiation of 2,2-diazido-2,3-dihydroinden-1-one (1) in methanol mainly yielded methyl 2-cyanomethylbenzoate (2) and 2-cyanomethylbenzoic acid (3) via α-cleavage. Laser flash photolysis of 1 in argon-saturated acetonitrile resulted in α-cleavage to form triplet biradical 31Br1 (λmax ∼ 410 nm, τ ∼ 400 ns). In contrast, upon irradiation in glassy 2-methyltetrahydrofuran matrices, triplet alkylnitrene 31N was directly detected using electron spin resonance (D/hc = 1.5646 cm-1, E/hc = 0.00161 cm-1) and absorption spectroscopy (λmax = 276 and 341 nm). Irradiation of 1 in argon matrices generated 31N, benzoyl azide 4, singlet benzoylnitrene 14N, and isocyanide 5, as revealed by IR spectroscopy. The experimental results supported by density functional theory calculations [B3PW91/6-311++G(d,p)] suggest that irradiation of 1 in matrices results in α-cleavage to form biradical 31Br1, which extrudes N2 to yield 31Br2. Rearrangement of 31Br2 into 31N competes with cleavage of a N3 radical to form radical 1Ra3. The N3/1Ra3 radical pair combines to form 4, which upon irradiation yields 14N and 5.

Iodine-Promoted Reductive Sulfenylation Using Ketones as Hydride Donors

Herein, an iodine-promoted reductive sulfenylation reaction of ketones with disulfides has been developed. This method provides an approach for synthesizing unsymmetrical alkyl-alkyl and alkyl-aryl sulfides in a single step. Investigation of the reaction mechanism revealed that ketones play a dual role in this process. They react with disulfides to produce vinyl thioethers and act as effective organic hydride donors, reducing the number of vinyl thioethers that are formed in situ. This study expands the range of applications of ketones in chemical synthesis.

Enhanced activation of peroxymonosulfate for advanced oxidation processes using solid waste: A novel and easy implement high-value utilization process of slag

A simple, efficient and low energy-consuming process available to generate resultful radicals from PMS for organic pollutants removal had been employed in this study. Slag had been used as the activator for organic pollutants degradation under slag/PMS advanced oxidation process. In this work, effects of slag with or without pretreatment on pollutant removal were studied and radical species generated by slag were measured. Calcination pretreatment is one efficient method to enhance the degradation efficiency significantly. Due to Fe3O4 and Fe2O3 became the dominant phases after calcination, it was about 8.6-flods increasing after comparing the pollutant removal efficiency for different slag/PMS system with calcination pretreatment or not. Organic pollutant neither degraded in PMS system at 25 °C nor being absorbed by slag system for 60 min. On the contrary, up to 90% pollutant concentration reduction achieved in the slag/PMS process. During this process, both •OH and SO4•- had been detected once slag and PMS interaction in wastewater. Through the free radicals quenching tests,•OH should be the key free radical in this advanced oxidation process for the organic pollutant removal under this alkaline condition. In general, organic degradation rate was determined by the slag dosage, and the maximum degradation efficiency was mainly controlled by the PMS usage. This work is expected to broaden the high-value reutilization way for industrial solid waste.

Dibenzoylperoxide as a Versatile Oxidant for Oxidative Azidations of Phenols Using Quaternary Ammonium Iodides or Bromides

Dibenzoylperoxide emerged as a versatile oxidant for quaternary ammonium iodide or bromide‐catalyzed reactions of phenol derivatives with NaN3. While the use of iodides allowed for efficient benzylic azidations under these oxidative conditions, the use of bromides allowed for dearomative azidations instead. Both approaches have been successfully applied to different phenol derivatives and a first proof‐of‐concept for an enantioselective variant using chiral quat. ammonium bromides has been obtained as well.

Reactions with Geminal Diazides: Long Known, Full of Surprises, and New Opportunities

Geminal diazides are uncommon yet powerful tools in organic synthesis. The chemistry of this class of functional compounds is characterized by quite unusual reactivities, including fragmentations and degradations, along with known reactions of organic azides. This Short Review highlights the major reactivities of various structural units having geminal diazido moieties, and provides an overview on the synthetic opportunities of such compounds.

1 Introduction

2 Preparation of Geminal Diazides

3 Reactivities of Geminal Diazides

3.1 α,α-Diazido Carbonyls

3.2 1,3-Diketones

3.3 Diazidated β-Ketoesters

3.4 Diazidated Malonates

3.5 Diazidated Malonamides

3.6 Miscellaneous Geminal Diazides

4 Conclusion

An Expedient Method for the Umpolung Coupling of Enols with Heteronucleophiles**

In this paper, we present an unprecedented and general umpolung protocol that allows the functionalization of silyl enol ethers and of 1,3‐dicarbonyl compounds with a large range of heteroatom nucleophiles, including carboxylic acids, alcohols, primary and secondary amines, azide, thiols, and also anionic carbamates derived from CO₂. The scope of the reaction also extends to carbon‐based nucleophiles. The reaction relies on the use of 1‐bromo‐3,3‐dimethyl‐1,3‐dihydro‐1λ³[d][1,2]iodaoxole, which provides a key α‐brominated carbonyl intermediate. The reaction mechanism has been studied experimentally and by DFT, and we propose formation of an unusual enolonium intermediate with a halogen‐bonded bromide.