A Novel Base-Catalyzed Stereoselective Synthesis of Trifluoromethylated Dienedinitriles

Abstract

The trifluoromethylated γ-cyano-β,γ-unsaturated nitrile 4 was prepared by the reaction of bromo(cyanomethyl)zinc with trifluoroacylated phosphonate 3 in 67% yield (E:Z = 60:40). The E- and Z-isomers obtained were easily separated by column chromatography. Treatment of a catalytic amount of t-BuOK (20 mol%) with a mixture of (Z)-4 and N-toluenesulfonylimines 5 gave trifluoromethylated dienedinitriles 6 in 68-83% yields.

Key words

trifluoromethylated dienedinitriles - γ-cyano-β,γ-unsaturated nitrile - trifluoroacylated phosphonate - organozinc reagent - stereoselective synthesis

References

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10

Crystallographic data of 6e have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication No. CCDC-208198(6e). Copies of the data can be obtained, free of charge, on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: [phone] or e-mail: [e-mail]).