1: (n-propyl)-triphenylphosphonium bromide With sodium hexamethyldisilazane in tetrahydrofuran T=0 - 20°C; Wittig reaction; Inert atmosphere; 2: 15-oxo-pentadecanoic acid methyl ester in tetrahydrofuran T=-78 - 20°C; Wittig reaction; Inert atmosphere; stereoselective reaction;