2,2,2-trimethylacetic acid in various solvent(s) 24 h; Heating;

1: 1.) BuLi / 1.) THF, hexane, -78 deg C, 40 min, 2.) THF, hexane, a) -78 deg C, 50 min, b) 25 deg C, 20 min 2: 100 percent / Hg/Nafion-H, H2O / ethanol / 1.5 h / 25 °C View Scheme

n-butyllithium 1.) THF, hexane, -78 deg C, 40 min, 2.) THF, hexane, a) -78 deg C, 50 min, b) 25 deg C, 20 min; Yield given. Multistep reaction;

1: triethyl orthopropiolate With n-butyllithium in tetrahydrofuran T=-78°C; 2: 4-methyl-[1,3,2]dioxathiolane 2,2-dioxide in tetrahydrofuran T=-78 - 20°C;

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: Et3N / (PPh3)2PdCl2, CuI / 4 h / Ambient temperature 2: p-toluenesulfonic acid / benzene / 12 h / Ambient temperature View Scheme