Epoxidation advance may spur its industrial use

Abstract

Asymmetric epoxidation of allylic alcohols finally has been made truly catalytic [ J. Org. Chem ., 51 , 1922 (1986)]. This advance may accelerate industrial use of the reaction to make optically pure intermediates for drugs and pheromones. Engineers at Upjohn already have used the stoichiometric version of the reaction to convert (2 E )-octenl- ol to (3 S )-pentyloxirane-(2 S )-methanol on a multikilo scale. In the future, Upjohn may switch to the catalytic version. Aldrich Chemical offers enantiomers of eight substituted glycidols and their esters made with the catalytic version. And Arco Chemical plans to use it to produce the two enantiomers of glycidol. Invented by organic chemistry professor K. Barry Sharpless at Stanford University in 1980, asymmetric epoxidation uses titanium(IV) isopropoxide and diethyl (+)- or (-)-tartrate to effect reaction of tertbutyl hydroperoxide with allylic alcohol substrates. Chemists can predict and direct the enantiomer to be made by sketching the geometry of the substr...