Stereospecific conversion of (1R*,3S*)- and (1R*,3R*)-3-cyclohexyl-1-phenylpropane-1,3-diol into the corresponding 2,4-disubstituted oxetanes

Conversion of two diastereoisomeric 1,3-diols (3-cyclohexyl-1-phenylpropane-1,3-diol) into orthoesters was followed by treatment with acetyl bromide. The 1,3-bromo acetates (acetic acid 3-bromo-1-cyclohexyl-3-phenylpropyl esters) were obtained with complete inversion of configuration at a benzylic site. Methanolysis of the bromo acetates, followed by ring-closure, resulted in a second inversion of configuration at a benzylic site to give the corresponding oxetanes with overall retention of configuration.