First Highly Stereoselective Synthesis of Fungicide Systhane

Abstract [reaction: see text] Highly enantiopure (R)-2-p-chlorophenyl-2-(1H-1,2,4-triazol-1-ylmethyl)hexanenitrile 1 (myclobutanil or systhane) was obtained in six synthetic steps from commercially available 1-hexyne (35% yield, 92% ee). The sulfinyl group controls the two key steps of the synthetic sequence, the highly stereoselective hydrocyanation of vinyl sulfoxides with Et(2)AlCN and the further introduction of the proper functionality into the molecule.