At this point in the synthesis of Taxol, the material was a racemic mixture. To obtain the desired enantiomer, allylic alcohol 4.9 was acylated with (1S)-(−)-camphanic chloride and dimethylaminopyridine, giving two diastereomers. These were then separated using standard column chromatography. The desired enantiomer was then isolated when one of the separated disatereomers was treated with potassium bicarbonate in methanol.