1: With trifluoromethylsulfonic anhydride in dichloromethane T=0°C; 0.5 h; Inert atmosphere; 2: With n-pentylmercaptane; N-ethyl-N,N-diisopropylamine in dichloromethane T=20°C; 16 h; Inert atmosphere;

1,1,3,3-tetramethyldisiloxane; titanium(IV) isopropylate in various solvent(s) T=100°C; 7 h;

potassium tert-butylate

in ethanol; benzene refluxing soln. of Lewis acid and ligand (molar ratio 1.1:1), 2-3h; evapn.; filtration; washing (benzene/ethanol, petroleum ether); drying; elem. anal.;