HPtCl6·6H2O in tetrahydrofuran refluxing (2 h); evapn. of solvent, distn. (74-76°C/1.5 Torr); product mixt. (3-substituted/2-substituted=18:82) not sepd.; total yield 67percent;

dihydrogen hexachloroplatinate in neat (no solvent) product ratio E:Z:α-substituted isomer 14:34:52 (GLC);