Correction to “Uncovering the Mechanism of the Ag(I)/Persulfate-Catalyzed Cross-Coupling Reaction of Arylboronic Acids and Heteroarenes”

Correction to “Uncovering the Mechanism of the Ag(I)/Persulfate-Catalyzed Cross-Coupling Reaction of Arylboronic Acids and Heteroarenes

Phenol Derivatives as Coupling Partners with Alkylsilicates in Photoredox/Nickel Dual Catalysis

Photoredox/nickel dual catalysis via single electron transmetalation allows coupling of C_sp³–C_sp² hybridized centers under mild conditions. A procedure for the coupling of electron-deficient aryl triflates, -tosylates, and -mesylates with alkylbis­(catecholato)­silicates is presented. This method represents the first example of the use of phenol derivatives as electrophilic coupling partners in photoredox/nickel dual catalysis

Mechanistic Study of Silver-Catalyzed Decarboxylative Fluorination

The silver-catalyzed fluorination of aliphatic carboxylic acids by Selectfluor in acetone/water provides access to fluorinated compounds under mild and straightforward reaction conditions. Although this reaction provides efficient access to fluorinated alkanes from a pool of starting materials that are ubiquitous in nature, little is known about the details of the reaction mechanism. We report spectroscopic and kinetic studies on the role of the individual reaction components in decarboxylative fluorination. The studies presented herein provide evidence that Ag­(II) is the intermediate oxidant in the reaction. In the rate-limiting step of the reaction, Ag­(I)-carboxylate is oxidized to Ag­(II) by Selectfluor. Substrate inhibition of the process occurs through the formation of a silver-carboxylate. Water is critical for solubilizing reaction components and ligates to Ag­(I) under the reaction conditions. The use of donor ligands on Ag­(I) provides evidence of oxidation to Ag­(II) by Selectfluor. The use of sodium persulfate as an additive in the reaction as well as NFSI as a fluorine source further supports the generation of a Ag­(II) intermediate; this data will enable the development of a more efficient set of reaction conditions for the fluorination

Uncovering the Mechanism of the Ag(I)/Persulfate-Catalyzed Cross-Coupling Reaction of Arylboronic Acids and Heteroarenes

The catalytic cross-coupling of arylboronic acids with pyridines through single-electron oxidation provides efficient access to substituted heterocycles. Despite the importance of this reaction, very little is known about its mechanism, and as a consequence, it is unclear whether the full scope of the transformation has been realized. Here we present kinetic and spectroscopic evidence showing a high degree of complexity in the reaction system. The mechanism derived from these studies shows the activation of Ag­(I) for reduction of persulfate and an off-cycle protodeboronation by the pyridine substrate. These results provide key mechanistic insights that enable control of the off-cycle process, thus providing higher efficiency and yield

<i>O</i>‑Benzyl Xanthate Esters under Ni/Photoredox Dual Catalysis: Selective Radical Generation and Csp³–Csp² Cross-Coupling

Alkyl xanthate esters are perhaps best known for their use in deoxygenation chemistry. However, their use in cross-coupling chemistry has not been productive, which is due, in part, to inadequate xanthate activation strategies. Herein, we report the use of <i>O</i>-benzyl xanthate esters, readily derived from alcohols, as radical pronucleophiles in Csp³–Csp² cross-couplings under Ni/photoredox dual catalysis. Xanthate (C–O) cleavage is found to be reliant on photogenerated (<i>sec</i>-butyl) radical activators to form new carbon-centered radicals primed for nickel-catalyzed cross-couplings. Mechanistic experiments support the fact that the key radical components are formed independently, and relative rates are carefully orchestrated, such that no cross reactivity is observed

Engaging Alkenyl Halides with Alkylsilicates via Photoredox Dual Catalysis

Single-electron transmetalation via photoredox/nickel dual catalysis provides the opportunity for the construction of C_sp³–C_sp² bonds through the transfer of alkyl radicals under very mild reaction conditions. A general procedure for the cross-coupling of primary and secondary (bis-catecholato)­alkyl­silicates with alkenyl halides is presented. The developed method allows not only alkenyl bromides and iodides but also previously underexplored alkenyl chlorides to be employed