1.1: potassium tert-butylate / tetrahydrofuran / 0.5 h / 20 °C / Inert atmosphere 1.2: 3.25 h / 0 - 20 °C 2.1: hydrogenchloride / water; tetrahydrofuran / 18 h / 20 °C 2.2: pH 6.8 / Aqueous phosphate buffer View Scheme

1: (3aR,4R,5R,6aS)-5-(tert-butyldimethylsilyloxy)-4-((R)-3-(tert-butyldimethylsilyloxy)-5-phenylpentyl)hexahydro-2H-cyclopenta[b]furan-2-ol; triphenylphosphonium salt of ω-bromopentanoic acid in tetrahydrofuran T=-15 - -5°C; Inert atmosphere; 2: With water; ammonium chloride in tetrahydrofuran; n-heptane; ethyl acetate T=15 - 30°C; 3: 2-iodo-propane

1.1: potassium tert-butylate / tetrahydrofuran / 0.5 h / 20 °C / Inert atmosphere 1.2: 3.25 h / 0 - 20 °C 2.1: hydrogenchloride / water; tetrahydrofuran / 18 h / 20 °C 2.2: pH 6.8 / Aqueous phosphate buffer 3.1: Novozym 435 / 18 h / 30 °C View Scheme