title: Design of sulfides with a locked conformation as promoters of catalytic and asymmetric sulfonium ylide epoxidation.
abstract: [reaction: see text] A new generation of 2,5-dimethylthiolanes with a locked conformation was developed to promote the asymmetric addition of chiral sulfonium ylides to aldehydes. The novel chiral sulfur derivative 4 succeeded the synthesis of trans-stilbene oxide derivatives with enantiomeric ratios ranging from 95:5 to 98:2. This user-friendly organocatalytic process proved to be efficient with 20-10% of sulfide 4 in 1 or 2 days of reaction. An insight into the ylide intermediate conformation is given on the basis of a computational ab initio study.
authors.affiliation: Laboratoire de Chimie Moléculaire et Thio-organique (UMR CNRS 6507), ENSICaen-Université de Caen, 6 Boulevard du Maréchal Juin, 14050 Caen, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Davoust
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Brière
authors.forename: Paul-Alain
authors.initials: PA
authors.lastname: Jaffrès
authors.forename: Patrick
authors.initials: P
authors.lastname: Metzner