Stereoselective TiCl4-promoted nucleophilic substitution at C-2 of (4S,5S)-2-alkyl-4-methyl-5-trifluoromethyl-1,3-dioxolanes

TiCl4-mediated nucleophilic ring-opening reactions of chiral acetals derived from (2S,3S)-1,1,1-trifluorobutane-2,3-diol proceed in a completely regioselective manner, leading to the break of the O1-C2 bond accompanied by a high degree of stereoselectivity. The use of triethylsilyl deuteride or allyltributyltin as nucleophiles gives access, after removal of the chiral auxiliary, to stereoselectively deuterated primary alcohols or homoallylic secondary alcohols, respectively, with high enantiomeric excesses.