in hexane addn. of C3O2 to AlMe3 (1:5, hexane) under stirring at -78°C, warming to room temp., standing for 4 h; evapn. (vac.), distn. (vac.), diln. with hexane, cooling to -30°C and hydrolysing (NH4Cl-NH3-buffer, pH 8);

tin(IV) chloride

diethyl ether

in hexane addn. of C3O2 to AlMe3 (1:2, hexane) under stirring at -78°C, warming to room temp., standing for 10 h; cooling to -30°C, hydrolysing with NH4Cl-NH3-buffer (pH 8), preparative TLC (hexane-acetone);