Regioselective Cyclodehydration of Chiral Diols with Diethoxytriphenylphosphorane, Triphenylphosphine-Tetrachloromethane-Potassium Carbonate, and Triphenylphosphine-Diethyl Azodicarboxylate Reagents. A Comparative Study

Article abstract of DOI:10.1021/jo00174a059

The regioselectivity of cyclodehydration of chiral diols has been examined with the reagents diethoxytriphenylphosphorane, triphenylphosphine-tetrachloromethane-potassium carbonate, and triphenylphosphine-diethyl azodicarboxylate. (S)-(+)-Propane-1,2-diol and (R)-(-)-pentane-1,4-diol afford 80-87percent retention of stereochemistry at the chiral carbon in the ether while (S)-(+)-phenylethane-1,2-diol affords essentially racemic styrene oxide with all three reagents.