Stereospecific or Stereoselective Elimination of vicinal-Alkoxyiodoalkanes by Means of Organometallic Reagents

Stereospecific or stereoselective elimination reactions of vicinal alkoxyiodoalkanes provide both stereo- and regiochemically defined alkenes via organometallic reagents. Three different reaction conditions have been developed. The first is the organolithium-induced stereospecific syn-elimination of a β-methoxy alkyl iodide. This method can be successfully applied to the interconversion of olefinic geometrical isomers. The second is a stereoselective elimination using a Grignard reagent. An isomeric mixture of alkenes can be converted into a pure (E)-alkene by this method. Finally, allylsilane/TiCl4-mediated stereospecific anti-elimination of iodoalkoxyalkanes is described. These methods provide new routes for the stereoselective synthesis of alkenes. Stereoselective synthesis of the substrates is also discussed.