177.3 mg of rac-(2RS,3RS,5SR)-2-hexyl-3-hydroxy-5-undecyl-δ-valerolactone (Example 1c)), 750 ml of TBME, 86.7 g of 97% 3,4-dihydro-2H-pyran and 0.314 g of pyridinium p-toluenesulphone were stirred at 50° under argon for 20 hours. 500 ml of 2N sodium hydroxide solution were added to the reaction solution. After stirring at 50° for 2.5 hours the aqueous phase was separated and the organic phase was washed with 500 ml of 10% sodium chloride solution. salt slurry was cooled, treated under argon in succession with 152.7 g of benzyl bromide and 99.1 g of Na t-butylate and stirred at room temperature for 24 hours. After adding 750 ml of 2N hydrochloric acid and stirring at 50° for 22 hours the mixture was cooled, the aqueous phase was separated and the organic phase was washed with sodium chloride solution, dried and filtered. After evaporation of the solvent there were obtained 349.8 g of rac-(2RS,3RS,5SR)-5-benzyloxy-2-hexyl-3-hydroxy-decanoic acid (the product of Examples 1g and 12c)).
