thallium ethylate 1) benzene, reflux, 1 h, 2) benzene, reflux, 5 min; Yield given. Multistep reaction. Yields of byproduct given;

1: 1.55 g / bis(triphenylphosphine)tetrahydroboratocopper(I), triphenylphosphine / acetone / 0.5 h / Heating 2: 0.52 g / tris(triphenylphosphine)chlororhodium(I) / 2 h / 180 °C 3: 0.30 g / selenium dioxide / acetic acid / 1 h / Heating View Scheme