Diarylprolinol in the Direct Asymmetric Aldol Reaction of Trifluoromethylacetaldehyde Ethyl Hemiacetal with Aldehyde

Asymmetric direct aldol reaction of trifluoromethylacetaldehyde with aldehyde using diarylprolinol as a catalyst, to afford a synthetically useful beta-trifluoromethyl-beta-hydroxy aldehyde with excellent enantioselectivity, was developed. Commercially available trifluoromethylacetaldehyde ethyl hemiacetal was used directly as a precursor of trifluoromethylacetaldehyde without acid pyrolysis or distillation prior to use.