title: Highly enantioselective organocatalytic sulfa-Michael addition to alpha,beta-unsaturated ketones.
abstract: A cinchona alkaloid-derived urea was found to be an efficient organocatalyst for catalyzing enantioselective conjugate addition between thiols and various alpha,beta-unsaturated ketones to provide optically active sulfides with high chemical yields (up to >99%) and enantiomeric excess (up to >99% ee). The reaction was performed with 0.1 mol % of catalyst in toluene at room temperature. A transition state model has been proposed to explain the stereochemical outcome of the reaction.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Kanpur, India 208 016.
authors.forename: Nirmal K
authors.initials: NK
authors.lastname: Rana
authors.forename: Sermadurai
authors.initials: S
authors.lastname: Selvakumar
authors.forename: Vinod K
authors.initials: VK
authors.lastname: Singh