The hydroxyl group is protected by a benzyl group and the carboxylic acid is activated by reaction with thionyl chloride to the acid chloride. The acid chloride reacts with the chiral auxiliary trans-2-phenyl-1-cyclohexanol.
In this specific compound, the hydroxyl group is safeguarded by a benzyl group, and the carboxylic acid is amplified through its reaction with thionyl chloride to form an acid chloride. This acid chloride then reacts with the chiral auxiliary trans-2-phenyl-1-cyclohexanol.