carbon monoxide; tri-ruthenium(0)dodecacarbonyl T=200°C; P=14710.2 Torr; 48 h;

tin(IV) chloride in benzene T=30°C; Friedel-Crafts acylation; 3 h;

1: With potassium fluoride on basic alumina; N-benzyl-N,N,N-triethylammonium chloride; zinc(II) chloride in acetonitrile T=20°C; insertion; 24 h; 2: With sodium hydroxide; dihydrogen peroxide in acetonitrile T=40°C; Oxidation; 2 h;

in tetrahydrofuran T=-15 - 20°C; 0.5 h;

tetrachlorosilane; benzene anschliessendes Behandeln mit Thiophen und Zinn(IV)-chlorid;