EFFICIENT STEREOSELECTIVE SYNTHESIS OF ALL GEOMETRICAL-ISOMERS OF HEPTADECA-11,13-DIENES

All geometrical isomers of heptacosa-11,13-dienes, 1-4, previously ide ntified in termite Prorhinotermes simplex cuticular hydrocarbons, were efficiently synthesized according Peterson-Hudrlik olefination proced ure in high stereoisomeric purity using syn and anti elimination of er ythro alkenyl-beta-hydroxysilanes (15 and 17). These (Z)- and (E)-alke nyl-beta-hydroxysilanes are available from regioselective opening of ( 1R,2S*)-1,2-epoxy-1-trimethylsilylpentadecane 13 with corresponding ( Z)- and (E)-dodec-1-enyl cuprates (14 and 16). Stereoisomeric purity o f obtained dienes 1-4 was higher than 95% (C-13 NMR).