The enantioselective trifluoromethylation of aromatic aldehydes by quaternary ammonium bromide and (IPr)CuF at low catalyst loading

A general catalytic enantioselective trifluoromethylation of aromatic aldehydes using (IPr)CuF and quinidine-derived quaternary ammonium salt as catalysts has been developed. A wide range of aromatic aldehydes are converted to the corresponding products in up to 92% yield and 81% ee at 2 mol% of catalyst loading.

(IPr)CuF and quinidine-derived quaternary ammonium salt worked cooperatively in the catalytic enantioselective trifluoromethylation of aromatic aldehydes as catalysts.Figure optionsDownload as PowerPoint slideHighlights
► A cooperative catalyst for enantioselective trifluoromethylation has been developed.
► The hydroxy at C-9 has a significant influence on enantioselectivity.
► The reaction requires only 2 mol% of catalyst loading.
► The plausible catalytic cycle has been proposed.
► The initiation of Me3SiCF3 by (IPr)CuF is the key factor for the high performance.