Stereoselective Synthesis of Unhindered Olefins by 2-Fold Extrusion Reactions

Article abstract of DOI:10.1021/jo00053a013

Two-fold extrusion reactions of 1,3,4-thiadiazolines 1 provide a convenient stereoselective route to unhindered Z-olefins.An improved preparation of the thiadiazolines involves reaction of an aldehyde with H2S-hydrazine, followed by in situ oxidation of the intermediate predominantly trans thiadiazolidine 2.Stereospecific extrusion of nitrogen yields the cis-thiirane which upon treatment with triphenylphosphine affords the corresponding Z-alkene in good yields.