title: Development of a new carbon-carbon bond forming reaction. new organic chemistry of sulfur dioxide. Asymmetric four-component synthesis of polyfunctional sulfones.
abstract: At low temperature 1-alkoxy-1,3-dienes add to sulfur dioxide activated by a Lewis or Brønstedt acid and generate zwitterionic intermediates that can be quenched by enoxysilanes. The resulting beta,gamma-unsaturated silyl sulfinates can be desilylated and reacted with methyl iodide to provide polyfunctional sulfones. Exploratory studies of this four-component synthesis of sulfones are reported. Enantiomerically pure derivatives containing up to three new stereogenic centers can be obtained using enantiomerically pure (E,E)-1-alkoxy-2-methylpenta-1,3-dienes derived from alpha-methyl benzyl alcohols, including the Greene's chiral auxiliary. The stereochemistry of the reactions is consistent with a mechanism involving the suprafacial hetero-Diels-Alder addition of sulfur dioxide to the 1-alkoxy-1,3-dienes that are rapidly ionized into zwitterionic intermediates.
authors.affiliation: Section de Chimie, Université de Lausanne, BCH, CH-1015 Lausanne-Dorigny, Switzerland.
authors.forename: V
authors.initials: V
authors.lastname: Narkevitch
authors.forename: S
authors.initials: S
authors.lastname: Megevand
authors.forename: K
authors.initials: K
authors.lastname: Schenk
authors.forename: P
authors.initials: P
authors.lastname: Vogel