1: 6,8-bismercaptooctanoic acid With sodium hydride in tetrahydrofuran T=0°C; Metallation; 0.333333 h; 2: 3-Bromopropylphosphane in tetrahydrofuran Alkylation; 12 h; Heating;

1.1: 98 percent / NaBH4; H2O / ethanol / 5 h / 25 °C 2.1: NaH / tetrahydrofuran / 0.33 h / 0 °C 2.2: 80 percent / tetrahydrofuran / 12 h / Heating View Scheme