29549-62-0Relevant articles and documents
Enantioselective syntheses of sulfoxides in octahedral ruthenium(II) complexes via a chiral-at-metal strategy
Li, Zheng-Zheng,Wen, A-Hao,Yao, Su-Yang,Ye, Bao-Hui
supporting information, p. 2726 - 2733 (2015/03/30)
The preparation of chiral 2-(alkylsulfinyl)phenol compounds by enantioselective coordination-oxidation of the thioether ruthenium complexes with a chiral-at-metal strategy has been developed. The enantiomerically pure sulfoxide complexes δ-[Ru(bpy)2{(R)-LO-R}](PF6) (bpy is 2,2′-bipyridine, HLO-R is 2-(alkylsulfinyl)phenol, R = Me (δ-1a), Et (δ-2a), iPr (δ-3a), Bn (δ-4a), and Nap (δ-5a)) and δ-[Ru(bpy)2{(S)-LO-R}](PF6) (R = Me (δ-1a), Et (δ-2a), iPr (δ-3a), Bn (δ-4a), and Nap (δ-5a)) have been synthesized by the reaction of δ-[Ru(bpy)2(py)2]2+ or δ-[Ru(bpy)2(py)2]2+ with the prochiral thioether ligands 2-(alkylthio)phenol (HL-R), followed by enantioselective oxidation with m-CPBA as oxidant. The X-ray crystallography was used to verify the stereochemistry of ruthenium complexes and sulfur atoms. The configurations of the ruthenium complexes are stable during the coordination and oxidation reactions. Moreover, the chiral sulfoxide ligands are enantioselectively generated by controlling of the configuration of ruthenium centers in the course of oxidation reaction. That is, the δ configuration at the ruthenium center generates the S sulfoxide ligand; on the contrary, the δ configuration of the ruthenium complex originates the R sulfoxide ligand. Acidolysis of δ-[Ru(bpy)2{(R)-LO-R}](PF6) and δ-[Ru(bpy)2{(S)-LO-R}](PF6) complexes in the presence of TFA-MeCN afforded the chiral ligands (R)-HLO-R and (S)-HLO-R in 96-99% ee values, respectively. Importantly, the chiral ruthenium complexes can be recycled as δ/δ-[Ru(bpy)2(MeCN)2](PF6)2 and reused in a next reaction cycle with complete retention of the configurations at ruthenium centers.
Chemistry of Sulfenic Acids. 7. Reason for the High Reactivity of Sulfenic Acids. Stabilization by Intramolecular Hydrogen Bonding and Electronegativity Effects
Davis, Franklin A.,Jenkins, Linda A.,Billmers, Robert L.
, p. 1033 - 1040 (2007/10/02)
It is proposed that the reason sulfenic acids (RSOH) are so reactive and usually not isolated or even detected is that they form thiosulfinates (RS(O)SR) so readily.This is a consequence of the sulfenic acid hydrogen-bonded dimer, 1, which lowers the energy of activation for thiosulfinate formation.The stability of the few sulfenic acids that have been isolated can be explained in terms of steric, electronic, and intramolecular hydrogen-bonding effects which prevent dimer formation.The importance of these effects on the stability of simple unstable sulfenic acids was demonstrated by flash vacuum pyrolysis (FVP) and the thiosulfinate/vinyl sulfoxide ratio.A novel, high yield, rearrangement of sulfenic acid 19f to 1,3-benzothiazine 26 was observed.
