5407-91-0Relevant articles and documents
pH Dependence of the Lifetime of a Norrish II Biradical
Caldwell, Richard A.,Dhawan, S. N.,Moore, D. E.
, p. 5163 - 5166 (1985)
The transient spectroscopy of γ-phenylbutyrophenone in a 2:1 (v/v) methanol:water mixture has been studied as a function of pH.The lifetime of the Norrish II 1,4-biradical shows an excellent titration curve.The moderately strongly absorbing acidic form of the biradical has a lifetime of 125 ns, with λmax of the difference spectrum with starting material at 320 nm.The strongly absorbing basic form has a lifetime of 62 ns and λmax 325 nm.The pKa in the mixed solvent is 11.8.The pKa in pure water, based on solvent dependence of pKa values for phenols of similar acidity, is estimated as 10.2+/-0.2, essentially identical with a value reported for the acetophenone ketyl monoradical.
Photocatalyzed Decarboxylative Thiolation of Carboxylic Acids Enabled by Fluorinated Disulfide
Zubkov, Mikhail O.,Kosobokov, Mikhail D.,Levin, Vitalij V.,Dilman, Alexander D.
supporting information, p. 2354 - 2358 (2022/04/07)
Thiolation of carboxylic acids using a disulfide reagent having tetrafluoropyridinyl groups is described. The light-mediated process is performed using an acridine-type photocatalyst. Primary, secondary, tertiary, and heteroatom-substituted carboxylic acids can be thiolated, and the method can be applied to the late-stage modification of a range of naturally occurring compounds and drugs. The fluorinated pyridine fragment is believed to enable the C-S bond formation. The resulting sulfides were used as redox-active radical precursors.
Rh-Catalyzed Coupling of Aldehydes with Allylboronates Enables Facile Access to Ketones
Zhang, Kezhuo,Huang, Jiaxin,Zhao, Wanxiang
supporting information, (2022/02/21)
We present herein a novel strategy for the preparation of ketones from aldehydes and allylic boronic esters. This reaction involves the allylation of aldehydes with allylic boronic esters and the Rh-catalyzed chain-walking of homoallylic alcohols. The key to this successful development is the protodeboronation of alkenyl borylether intermediate via a tetravalent borate anion species in the presence of KHF2 and MeOH. This approach features mild reaction conditions, broad substrate scope, and excellent functional group tolerance. Mechanistic studies also supported that the tandem allylation and chain-walking process were involved.
Vinyl Azides as Radical Acceptors in the Vitamin B12-Catalyzed Synthesis of Unsymmetrical Ketones
Dworakowski, Krzysztof R.,Pisarek, Sabina,Hassan, Sidra,Gryko, Dorota
supporting information, p. 9068 - 9072 (2021/11/30)
Vinyl azides are very reactive species and as such are useful building blocks, in particular, in the synthesis of N-heterocycles. They can also serve as precursors of ketones. These form in reactions of vinyl azides with nucleophiles or radicals. We have found, however, that under light irradiation vitamin B12 catalyzes the reaction of vinyl azides with electrophiles to afford unsymmetrical carbonyl compounds in decent yields. Mechanistic studies revealed that alkyl radicals are key intermediates in this transformation.
