Development of a new carbon-carbon bond forming reaction. new organic chemistry of sulfur dioxide. Asymmetric four-component synthesis of polyfunctional sulfones.
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.
Narkevitch
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V
Section de Chimie, Université de Lausanne, BCH, CH-1015 Lausanne-Dorigny, Switzerland.
Megevand
S
S
Schenk
K
K
Vogel
P
P