in dimethyl sulfoxide T=25°C; 3.5 h;

1: triethyl orthopropiolate; 2-iodophenylacetic acid methyl ester With bis-triphenylphosphine-palladium(II) chloride; copper(l) iodide; triethylamine in acetonitrile T=0 - 20°C; Sonogashira coupling; 3.5 h; 2: methanol With toluene-4-sulfonic acid in benzene T=20°C; 12 h; Further stages.;

1.1: (COCl)2; DMF / tetrahydrofuran; benzene / 0.5 h / 0 °C 1.2: 79 percent / diethyl ether; tetrahydrofuran / 2 h / 0 °C 2.1: 86 percent / AgOBz; NEt3 / 0.5 h / 20 °C 3.1: PdCl2(PPh3)2; CuI; NEt3 / acetonitrile / 3.5 h / 0 - 20 °C 3.2: 85 percent / TsOH / benzene / 12 h / 20 °C View Scheme

1.1: 86 percent / AgOBz; NEt3 / 0.5 h / 20 °C 2.1: PdCl2(PPh3)2; CuI; NEt3 / acetonitrile / 3.5 h / 0 - 20 °C 2.2: 85 percent / TsOH / benzene / 12 h / 20 °C View Scheme