A new catalytic procedure for the asymmetric oxidation of aryl alkyl and aryl benzyl sulfides to optically active sulfoxides by hydroperoxides is described. This oxidation of sulfides is mediated by a chiral Ti complex formed in situ by reacting Ti(i-PrO)4, (R,R)-diphenylethane-1,2-diol (1), and water. The conditions of the reaction (stoichiometric composition of the catalyst, temperature, and the presence of additives and solvent) have been determined in order to reach the highest enantioselectivity and avoid the intervention of a kinetic resolution process. The oxidation protocol described herein is quite versatile as the values of chemical yields (60- 73%) and of enantioselectivity (ee 70-80%) achieved for aryl alkyl sulfides are almost independent of the nature of the aryl substituent and of the size of the alkyl group. Notably, aryl benzyl sulfides, which are poor substrates for the Ti/DET catalyzed oxidations, afforded very high ee's (92-99%) with this oxidation system.

Catalytic Asymmetric Oxidation of Aryl Sulfides with a Ti/H2O/(R,R)-Diphenylethane-1,2-diol Complex: a Versatile and Highly Enantioselective Oxidation Protocol

SUPERCHI, Stefano;ROSINI, Carlo
1998

Abstract

A new catalytic procedure for the asymmetric oxidation of aryl alkyl and aryl benzyl sulfides to optically active sulfoxides by hydroperoxides is described. This oxidation of sulfides is mediated by a chiral Ti complex formed in situ by reacting Ti(i-PrO)4, (R,R)-diphenylethane-1,2-diol (1), and water. The conditions of the reaction (stoichiometric composition of the catalyst, temperature, and the presence of additives and solvent) have been determined in order to reach the highest enantioselectivity and avoid the intervention of a kinetic resolution process. The oxidation protocol described herein is quite versatile as the values of chemical yields (60- 73%) and of enantioselectivity (ee 70-80%) achieved for aryl alkyl sulfides are almost independent of the nature of the aryl substituent and of the size of the alkyl group. Notably, aryl benzyl sulfides, which are poor substrates for the Ti/DET catalyzed oxidations, afforded very high ee's (92-99%) with this oxidation system.
File in questo prodotto:
File Dimensione Formato  
JOC_1998_9392.pdf

solo utenti autorizzati

Descrizione: pdf finale
Tipologia: Pdf editoriale
Licenza: DRM non definito
Dimensione 53.32 kB
Formato Adobe PDF
53.32 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11563/15488
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 133
  • ???jsp.display-item.citation.isi??? 124
social impact