The Regio-specific solvent controlled asymmetric Strecker reaction of trifluoromethyl α,β-unsaturated N-tert-butanesulfinyl ketimines with trimethylsilyl cyanide

The stereoselectivity of the reaction of (Rs)-trifluoromethyl α,β-unsaturated N-tert-butanesulfinyl ketimines with TMSCN was studied. The diastereomers of α-trifluoromethyl unsaturated cyano amines were obtained, respectively, in good yields with excellent diastereoselectivities in terms of the different solvents used. In c-hexane, the (S, Rs)-isomer was obtained with up to 17:1 dr, whereas the (R, Rs)-isomer was generated as the main product with up to 145:1 dr in DMF at −60 °C.

Graphical abstractThe stereoselectivity of the reaction of (Rs)-trifluoromethyl α,β-unsaturated N-tert-butanesulfinyl ketimines with TMSCN was studied. The diastereomers of α-trifluoromethyl unsaturated cyano amines were obtained, respectively, in good yields with excellent diastereoselectivities in terms of the different solvents used. In c-hexane, the (S, Rs)-isomer was obtained with up to 17:1 dr, whereas the (R, Rs)-isomer was generated as the main product with up to 145:1 dr in DMF at −60 °C.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The reaction of chiral N-tert-butanesulfinyl ketimines with TMSCN was studied. ► Different diastereoselectivities were obtained in terms of the solvents used. ► In c-hexane, d.r. (2a:3a) of the addition products is up to 1:17. ► In DMF, a reversed diastereoselectivity was observed with up to 145:1 d.r. (2a:3a).