Diastereoselective Copper-Catalyzed Defluorosilylation of Pentafluoroethyl Alkenes to Access Polyfluorinated Allylsilanes

Abstract

A highly diastereoselective copper-catalyzed defluorosilylation of pentafluoroethyl alkenes is described. In the presence of CuCN/PCy₃ catalyst, polyfluorinated allylsilanes containing an sp²-carbon connected to F and CF₃ can be synthesized with E-alkene geometry. Without the ligand, the Z-alkenes are obtained as major products. Moreover, a one-pot defluorosilylation/protodesilylation sequence affords the hydrodefluorination product, which can undergo another round of defluorosilylation to generate trifluoromethylated allylsilanes as Z-alkenes.

Keywords

Copper catalysis / Defluorosilylation / Diastereoselective / Fluoroalkene / Pentafluoroethyl / Allylsilane

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