In Situ Opening of Epoxy Alcohols: A Convenient Alternative to the Isolation of Unstable Epoxy Alcohols

The synthetic utility of the titanium-catalyzed asymmetric epoxidation has been demonstrated by numerous applications of the reaction to the synthesis of enantiomerically pure compounds. However, successful applications of the original epoxidation procedure have been elusive for small epoxy alcohols, especially those bearing a terminal epoxy group, among which glycidol (1) and 2-methylglycidol (2) are of particular importance as chiral building blocks. The problems often cited in the production of these epoxy alcohols are their propensity for undergoing ring-opening reactions and their water solubility. Although recent developments in the catalytic version of the process and the nonaqueous workup procedure have made it possible to obtain these epoxy alcohols in good yield and high enantiomeric purity, difficulties are still encountered during workup, distillation, and storage.