An aqueous solution of sodium hydroxide (50% (w/w), 6 ml) was added portionwise to a mixture of (5Z,8Z,11Z,14Z,17Z)-icosa-5,8,11,14,17-pentaen-1-ol (2.01 g, 6.39 mmol), tert-butyl-2-bromobutyrat (2.85 g, 12.8 mmol) and tetrabutylammonium bisulfate (0.65 g, 1.91 mmol) in toluene (12 ml). The reaction mixture was vigorously stirred under N2-atmosphere and warmed to 50° C. The reaction mixture was stirred at 50° C. for a total of 22 hrs. Additional tert-butyl-2-bromobutyrat (1.43 g, 6.39 mmol) and (1.44 g, 6.44 mmol) was added after 1½ hrs and 3 hrs respectively. The mixture was cooled and added ice-water (˜50 ml) and heptane (50 ml), the phases were separated and the organic phase was concentrated under reduced pressure. Flash chromatography on silica gel (30 g) eluting with heptane-heptane/EtOAc (99:1) yielded 2.12 g of the title compound as a liquid. 1H NMR (300 MHz, CDCl3) δ 0.94-1.04 (m, 6H), 1.47 (s, 9H), 1.68-1.85 (m, 4H), 1.93-2.20 (m, 4H), 2.80-2.86 (m, 10H), 3.28-3.36 (m, 1H), 3.55-3.63 (m, 2H), 5.27-5.43 (m, 12H)
