1: diethoxyphosphoryl-acetic acid ethyl ester With sodium hydride in tetrahydrofuran T=20°C; Metallation; 0.5 h; 2: cyclo-octatrienone in tetrahydrofuran T=20°C; Horner-Wadsworth-Emmons reaction; 8 h;

toluene-4-sulfonic acid in benzene 20 h; Heating;

sodium hydroxide Erhitzen des Reaktionsprodukts;

lithium aluminium tetrahydride in diethyl ether T=-78°C; Reduction; 2 h;

1: 99 percent / LiAlH4 / diethyl ether / 2 h / -78 °C 2: 62 percent / Hg(OAc)2 / 36 h / 180 °C 3: 80 percent / O2; PdCl2; CuCl / dimethylformamide; H2O / 20 h / 20 °C 4: 75 percent / KOH / tetrahydrofuran; methanol / 8 h / 20 °C View Scheme