32110-48-8Relevant academic research and scientific papers
Waste-Free Swift Synthesis of Symmetrical and Unsymmetrical Diarylmethyl Thioethers from Diaryl Carbinols
Singh, Pallavi,Peddinti, Rama Krishna
, p. 3633 - 3642 (2017/08/15)
A waste-free and swift protocol to synthesize symmetrical and unsymmetrical diarylmethyl thioethers from diaryl carbinols and thiols in good to quantitative yields is reported. The thiol scope included alkyl and aryl thiols bearing electron-donating and electron-withdrawing groups. Short reaction time, high atom economy, inexpensive activator, free from workup and aryl halides, and gram-scale synthesis are the significant features of the new protocol.
Palladium-catalyzed direct α-arylation of benzyl thioethers with aryl bromides
Frensch, Gustavo,Hussain, Nusrah,Marques, Francisco A.,Walsh, Patrick J.
supporting information, p. 2517 - 2524 (2014/09/29)
The arylation of sp3-hybridized C-H bonds is a powerful strategy to build molecular complexity and diversity. A novel and efficient palladium-catalyzed direct sp3 C-H arylation of aryl and alkyl benzyl thioether derivatives with aryl bromides is reported. The reaction involves reversible deprotonation of the benzylic C-H bond of the thioether with either lithium or sodium bis(trimethylsilyl)amide [LiN(SiMe3)2 or NaN(SiMe3)2] and subsequent cross-coupling to provide the functionalized products in up to 97% yield. A screen of 24 of the most successful ligands in cross-coupling chemistry led to the identification of NiXantPhos as the only viable ligand for this challenging coupling.
Electron transfer to sulfides and disulfides: Intrinsic barriers and relationship between heterogeneous and homogeneous electron-transfer kinetics
Meneses, Ana Belen,Antonello, Sabrina,Arevalo, Maria Carmen,Gonzalez, Concepcion Carmen,Sharma, Jadab,Wallette, Andrea N.,Workentin, Mark S.,Maran, Flavio
, p. 7983 - 7995 (2008/04/01)
The electron-acceptor properties of series of related sulfides and disulfides were investigated in N,N-dimethylformamide with homogeneous (redox catalysis) and/or heterogeneous (cyclic voltammetry and convolution analysis) electrochemical techniques. The electron-transfer rate constants were determined as a function of the reaction free energy and the corresponding intrinsic barriers were determined. The dependence of relevant thermodynamic and kinetic parameters on substituents was assessed. The kinetic data were also analyzed in relation to corresponding data pertaining to reduction of diaryl disulfides. All investigated reductions take place by stepwise dissociative electron transfer (DET) which causes cleavage of the Calkyl-S or S-S bond. A generalized picture of how the intrinsic electron-transfer barrier depends on molecular features, ring substituents, and the presence of spacers between the frangible bond and aromatic groups was established. The reduction mechanism was found to undergo a progressive (and now predictable) transition between common stepwise DET and DET proceeding through formation of loose radical anions. The intrinsic barriers were compared with available results for ET to several classes of dissociative- and nondissociative-type acceptors, and this led to verification that the heterogeneous and the homogeneous data correlate as predicted by the Hush theory.
Unexpected differences in the α-halogenation and related reactivity of sulfones with perhaloalkanes in KOH-t-BuOH
Meyers, Cal Y.,Chan-Yu-King, Roch,Hua, Duy H.,Kolb, Vera M.,Matthews, Walter S.,Parady, Thomas E.,Horii, Toyokazu,Sandrock, Paul B.,Hou, Yuqing,Xie, Songwen
, p. 500 - 511 (2007/10/03)
Most alkyl phenyl sulfones are readily α-chlorinated with CCl4 and α-brominated with CBrCl3 in KOH-t-BuOH via radical-anion radical pair (RARP) reactions. While isopropyl mesityl sulfone (4) is easily α-chlorinated with CCl4, it was completely recovered when treated with the more reactive CBrCl3. Subsequent investigations showed the latter result to be due to the poor acidity of 4 together with the rapid depletion of CBrCl3 and KOH by their reaction with each other, and led to a variety of other important results. 4-Hydroxyphenyl isopropyl sulfone (6) is unreactive with either CCl4 or CBrCl3 in KOH-t-BuOH, its phenoxide anion strongly reducing the electronegativity of the sulfonyl group, thereby inhibiting α-anion formation. This effect is reversed by the electron-withdrawing influence of two α-phenyls, so that benzhydryl 4-hydroxyphenyl sulfone (8) is readily α-halogenated in KOH-t-BuOH with CCl4 or CBrCl3. On further contact with KOH-t-BuOH the α-halogenated sulfones from 8 are decomposed into benzophenone and phenol. While the α-halogenated derivatives of 4-methoxyphenyl benzhydryl sulfone (9) are stable to base, they are decomposed even under mildly acidic conditions into 4-methoxyphenyl 4-methoxybenzenethiolsulfonate (9c), phenol, and benzophenone. Mono-α-halogenation of benzyl phenyl sulfone (10) enhances the rate of the subsequent halogenation, so that α,α-dihalogenation is attained while much substrate is still present and the mono-α-halogenated product is not detected. The ease of reductive debromination of α-bromo sulfones with Cl3C- was correlated with the stability of the formed α-anions, explaining the success with α-bromobenzylic sulfones but failure with α-bromoalkyl sulfones. In the presence of air and the absence of competing halogenation, formation of the α-anions of alkyl aryl sulfones is quickly accompanied by oxidative cleavage by atmospheric O2, leading to the formation of arenesulfonyl alcohols, arenesulfonyl halides, and haloarenes.
