74851-75-5Relevant articles and documents
Site-Selective C?S Bond Formation at C?Br over C?OTf and C?Cl Enabled by an Air-Stable, Easily Recoverable, and Recyclable Palladium(I) Catalyst
Scattolin, Thomas,Senol, Erdem,Yin, Guoyin,Guo, Qianqian,Schoenebeck, Franziska
supporting information, p. 12425 - 12429 (2018/09/18)
This report widens the repertoire of emerging PdI catalysis to carbon–heteroatom, that is, C?S bond formation. While Pd0-catalyzed protocols may suffer from the formation of poisonous sulfide-bound off-cycle intermediates and lack of selectivity, the mechanistically diverse PdI catalysis concept circumvents these challenges and allows for C?S bond formation (S–aryl and S–alkyl) of a wide range of aryl halides. Site-selective thiolations of C?Br sites in the presence of C?Cl and C?OTf were achieved in a general and a priori predictable fashion. Computational, spectroscopic, X-ray, and reactivity data support dinuclear PdI catalysis to be operative. Contrary to air-sensitive Pd0, the active PdI species was easily recovered in the open atmosphere and subjected to multiple rounds of recycling.
Homolytic Bond Dissociation Energies of the Acidic C-H Bonds in α-Substituted and 10-Substituted 9-Methylanthracenes and Their Related Radical Anions
Zhang, Xian-Man,Bordwell, Frederick G.,Bares, Joseph E.,Cheng, Jin-Pei,Petrie, Brian C.
, p. 3051 - 3059 (2007/10/02)
Equilibrium acidities (pKHA), reduction potentials Ere(HA), oxidation potentials EOX(HA), and oxidation potentials of the conjugate anions EOX(A-) have been measured in dimethyl sulfoxide (DMSO) solution for 13 α-substituted 9-methylanthracenes (9-GCH2An) and 11 10-substituted 9-methylanthracenes (10-G-9-MeAn).The equilibrium acidities have been shown to be linearly correlated with Hammett ?- constants.The similar ρ- values for the linear correlations of pKHA vs ?- for 9-GCH2An (ρ- = 13.8) and 10-G-9-MeAn (ρ- = 14.2) demonstrate that the like substituents in 9-GCH2An and 10-G-9-MeAn have similar large effects on the equilibrium acidities.Suitable combinations of these equilibrium acidities with the reduction and oxidation potentials led to estimates of (a) the homolytic bond dissociation energies (BDEHA) of the acidic C-H bonds in 9-GCH2An and 10-G-9-MeAn, (b) the homolytic bond dissociation energies (BDEHA*-%) of the acidic C-H bonds in 9-GCH2An*- and 10-G-9-MeAn*- radical anions, and (c) the radical cation acidities (pKHA*+%) of the 9-GCH2An*+ and 10-G-9-MeAn*+ radical cations.Introduction of α-CN and α-NO2 groups had opposite effects on the strengths (BDEHA) of the acidic C-H bonds in 9-GCH2An; the α-CN group decreased the BDEHA value by 2.5 kcal/mol and the α-NO2 increased the BDEHA value by 4.5 kcal/mol, but they both weakened the acidic C-H bonds in 9-GCH2An*- radical anions (by 10.6 and 12.5 kcal/mol, respectively).The BDEs of the acidic C-H bonds in 10-G-9-MeAn were estimated to be 81.3 +/- 1.3 kcal/mol and those in the corresponding radical anions were estimated to be 58.5 +/- 2.5 kcal/mol.The 9-GCH2An*+ and 10-G-9-MeAn*+ radical cations are strongly acidic with the pKHA*+% values estimated in the range of -5 to -11 pKHA*+% units.Seven linear free energy relationships have been observed.
Sur le comportement cathodique inattendu des di-aryl sulfoxydes en solvant de tres faible acidite
Djeghidjegh, Nouredine,Simonet, Jacques
, p. 39 - 41 (2007/10/02)
When conducted in aprotic solvents the cathodic reduction of aromatic sulphoxides (only able to lead to an electron transfer under such conditions) does not afford the quantitative formation of the corresponding sulphides.On the contrary, one observes the conversion into a mixture sulphide/sulphone in a molar ratio 1/1 followed in most of the cases by the cathodic cleavage of the sulphone.Reasons for such a are analysed.
