The synthesis of two selectively deuterium-labelled 4-(((S)-1-((S)-1-((S)-2-methylbutoxy)-1- oxopropan-2-yloxy)-1-oxopropan-2-yloxy) carbonyl) phenyl 4′-(heptyloxy) biphenyl-4- carboxylate derivatives is reported. A new preparation strategy was developed in order to optimise the yields as well as the optical purity, this property being of fundamental importance for the optical applications of this ferroelectric liquid crystal.