1609274-93-2Relevant academic research and scientific papers
Enantioselective oxidation of thioethers to sulfoxides by means of a structural template with chiral-at-metal ruthenium complexes
Li, Zheng-Zheng,Yao, Su-Yang,Ye, Bao-Hui
, p. 141 - 150 (2015/02/05)
Treatment of cis-[Ru(bpy)2Cl2]·2H2O or Δ/Λ-[Ru(bpy)2(py)2]2+ (bpy=2,2′-bipyridine, py=pyridine) with the prochiral thioether ligands 2-alkylthiobenzoic acid (HOS-R) produces the corresponding thioether complexes rac-[Ru(bpy)2(OS-R)](PF6) (R=Me (rac-1), iPr (rac-2), 2-benzylthiobenzonate (Bn) (rac-3)) and Δ/Λ-[Ru(bpy)2(OS-R)](PF6) (R=Me (Δ-1/Λ-1), iPr (Δ-2/Λ-2), Bn (Δ-3/Λ-3)) with retention of the configurations at chiral metal centers. In situ oxidation of the thioether complexes by metachloroperoxybenzoic acid provides the corresponding sulfoxide complexes rac-[Ru(bpy)2(OSO-R)](PF6) (OSO-R is 2-alkylsulfinylbenzonate, R=Me (rac-1a), iPr (rac-2a), Bn (rac-3a)), Δ-[Ru(bpy)2{(R)-OSO-R}](PF6) (R=Me (Δ-1a), iPr (Δ-2a), Bn (Δ-3a)), and Λ-[Ru(bpy)2{(S)-OSO-R}](PF6) (R=Me (Λ-1a), iPr (Λ-2a), Bn (Λ-3a)) in yields of 95% with 98% ee values. The absolute configurations at the metal centers and sulfur atoms were determined by means of X-ray crystallography. The results indicate that the configurations of the metal centers are retained and have the function of controlling sulfoxide chirality during the oxidation process. The Δ metal-centered configuration enantioselectively generates an R-configuration sulfoxide, and the Λ configuration enantioselectively forms an S-configuration sulfoxide in the course of the in situ oxidation reaction, thereby resulting in a predetermined chirality of the sulfoxide ligands. The predetermined chirality of sulfoxides (S)-HOSO-R and (R)-HOSO-R were obtained by the treatments of the corresponding sulfoxide complexes Δ-[Ru(bpy)2{(R )-OSO-R}](PF6) and Λ-[Ru(bpy)2{(S)-OSO-R}](PF6) with trifluoroacetic acid in yields of 90% with 83.5-92.9% ee values.
In situ generation of sulfoxides with predetermined chirality via a structural template with a chiral-at-metal ruthenium complex
Li, Zheng-Zheng,Yao, Su-Yang,Wu, Jin-Ji,Ye, Bao-Hui
supporting information, p. 5644 - 5647 (2014/05/20)
The reaction of Δ/Λ-[Ru(bpy)2(py)2] 2+ with a prochiral sulfide ligand, and then in situ oxidation, provide the corresponding Δ-[Ru(bpy)2{(R)-OSO-iPr}]+ and Λ-[Ru(bpy)2{(S)-OSO-iPr}]+ (OSO-iPr = 2-isopropylsulfonylbenzonate) enantiomers in a yield of 83% with 98% ee. The chiral sulfoxides were obtained by treatment of the sulfoxide complexes with TFA in a yield of 90% with 88-91% ee. the Partner Organisations 2014.
