tetrakis(triphenylphosphine) palladium(0) in tetrahydrofuran heating in autoclave pressurized with CO2 (33 atm) at 70°C for 24h; cooling, releasing of the pressure, removal of the solvent; chromatography;

in dichloromethane; water at 20°C;

in dichloromethane; water at 20°C;

in benzene byproducts: H2O; mole ratio of (C4H9)3SnOSn(C4H9)3 and carboxylic acid 1:2; at 20°C or at reflux temp. to remove of water formed by azeotropic distn.;