A Unified Approach to Lactonization/Lactamization by Leveraging Tether-Tunable Distonic Radical Anions.

We report using visible-light-induced generation of tether-tunable distonic radical anions for the general catalytic lactonization/lactamization of aromatic carboxylic acids and benzamides. Its success relies on the specific cyclic diacyl peroxide and catalytic amount of CsI, enabling the generation of electrophilic heteroatom-centered radicals via a philicity regulation strategy. Key features include operational simplicity, excellent functional group tolerance, broad substrate scope, high chemo- and regioselectivity, gram-scale scalability, and application to synthesis of urolithin derivatives and 3--butylphthalide.

Trichloroacetonitrile as an efficient activating agent for the ipso-hydroxylation of arylboronic acids to phenolic compounds.

A metal-free and base-free ClCCN mediated method was developed for the ipso-hydroxylation of aryl boronic acids to their corresponding phenols, which was promoted by a key unstable Lewis adduct intermediate. This transformation has broad functional group tolerance, and late-stage functionalization was successful as well. After simple investigation, two pathways (radical/ionic mechanism) were suggested, and the beneficial action of blue light needs to be further studied.

Two catalytic protocols for Achmatowicz rearrangement using cyclic diacyl peroxides as oxidants.

In situ generated bromonium-catalyzed and visible-light photocatalytic Achmatowicz rearrangements of furfuryl alcohols using cyclic diacyl peroxides as oxidants are described. Both protocols feature broad substrate scope, excellent functional group tolerance, and mild reaction conditions, affording the synthetically useful dihydropyranone derivatives in good yields.

Sulfonamide-Directed Chemo- and Site-Selective Oxidative Halogenation/Amination Using Halogenating Reagents Generated in Situ from Cyclic Diacyl Peroxides.

The combination of cyclic diacyl peroxides with commercially available halide salts as a unique halogenating system is utilized in Hofmann-Löffler-Freytag-type reaction. This strategy allows for the formation of N-chloroamides, δ-brominated products, and even biologically relevant pyrrolidines under mild conditions in moderate to excellent yields. Meanwhile, the preliminary structure of the in situ formed brominating reagent is investigated by NMR and UV/vis analysis.

Visible-Light-Enhanced Ring Opening of Cycloalkanols Enabled by Brønsted Base-Tethered Acyloxy Radical Induced Hydrogen Atom Transfer-Electron Transfer.

A metal-free ring opening/halogenation of cycloalkanols, which combines both PPO/TBAX oxidant system and blue LEDs irradiation, is presented. This method produces diverse γ, δ, and even more remotely halogenated ketones in moderate to excellent yields under mild conditions. Interestingly, experimental and computational studies demonstrate the novel ring size-dependent concerted/stepwise (four-/five- to eight-membered rings) hydrogen atom transfer-electron transfer induced by Brønsted base-tethered acyloxy radical, which indicates distinct advantages brought by the cyclic structure of diacyl peroxides.

Correction: Metal- and additive-free oxygen-atom transfer reaction: an efficient and chemoselective oxidation of sulfides to sulfoxides with cyclic diacyl peroxides.

Correction for 'Metal- and additive-free oxygen-atom transfer reaction: an efficient and chemoselective oxidation of sulfides to sulfoxides with cyclic diacyl peroxides' by Shaoyan Gan et al., Org. Biomol.

Metal- and additive-free oxygen-atom transfer reaction: an efficient and chemoselective oxidation of sulfides to sulfoxides with cyclic diacyl peroxides.

Metal- and additive-free oxidation of a series of sulfides/thioketones has been achieved using cyclic diacyl peroxides as mild oxygen sources. This protocol features simple manipulation, high chemo- and diastereoselectivity, and a broad substrate scope (up to 42 examples), tolerates many common functional groups, and is scalable and applicable to the late-stage sulfoxidation strategy. A preliminary mechanistic study by quantum mechanical calculations suggests that a single two-electron transfer process is energetically more favorable, and indicates the reactivity of cyclic diacyl peroxides distinct from conventional acyclic acyl peroxides.

[3 + 2] Cycloadditions of Azides with Arynes via Photolysis of Phthaloyl Peroxide Derivatives.

Photolysis of phthaloyl peroxides yields arynes, which undergo [3 + 2] cycloadditions with azides. This reaction tolerates a variety of organic azides and phthaloyl peroxides and affords the corresponding benzotriazoles in moderate to good yields at room temperature.

Transition-metal-free cross-coupling of thioethers with aryl(cyano)iodonium triflates: a facile and efficient method for the one-pot synthesis of thiocyanates.

A novel transition-metal-free cross-coupling method for the one-step synthesis of thiocyanates via the C-S bond cleavage of readily available thioethers with aryl(cyano)-iodonium triflates as the cyanating agent is developed. This process features relatively broad substrate scopes, less-toxic hypervalent iodine reagents, mild operating conditions, excellent functional group compatibilities, and affords various thiocyanates in moderate to good yields.