Di-n-hexyl d-Tartrate. d-Tartaric acid (20 g), n-hexanol (150 mL) and p-toluenesulfonic acid hydrate (2 g) were mixed in a round-bottomed flask (250 mL) equipped with a Dean-Stark apparatus capped with a CaCl 2 -filled drying tube. The reaction mixture was heated to 200 °C and refluxed until all water produced during the reaction has been removed. After cooling to room temperature, the unreacted n-hexanol was removed by vacuum distillation. The cold yellowish distillation residue was poured into a saturated aqueous NaHCO 3 solution and extracted with dichloromethane. The collected organic phases were dried over Na 2 SO 4 and the solvent removed under reduced pressure to yield the product as an yellowish oil (39.5 g, 93 %). ). Di-n-hexyl tartrate (6 g) was dissolved in diethyl ether (200 mL), cooled with ice to 0 °C and periodic acid dihydrate (4.5 g) was added in small portions over 60 min. The resulting slurry was stirred in the melting ice-bath overnight. The ethereal solution was extracted with water (3 x 300 mL), dried over Na 2 SO 4 , and evaporated under reduced pressure. The oily residue was dissolved in dry hexane (100 mL) and phophorus oxide (~ 6 g) was added in several portions with intense stirring. The mixture was heated to 50 °C and stirred under Ar atmosphere for 60 min. The solvent was cannulated into a pre-dried flask and evaporated under reduced pressure. The greenish-yellow oil was immediately used in the subsequent step.