4-methylmorpholine N-oxide; propynoic acid ethyl ester in tetrahydrofuran T=0 - 20°C; Inert atmosphere;

in diethyl ether inert atmosphere, heated to 50°C, reacted for 3 h; evaporated (20°C, 15 Torr), chromatographed (silica gel, petroleum ether/ether (10:1)), recrystallized from petroleum ether, elem. anal.;

in tetrahydrofuran under inert gas; Cr-complex and thio-compound in dry THF, heated (1 h, 70°C), addn. of pyridine (20°C), 24 h at 20°C; crystn.;

in diethyl ether byproducts: acetophenone; addn. of the allene to the Cr complex, 4,5 h at 50°C; solvent removed (20°C, 15 Torr), separation by chropy. on silica gel in petroleum ether; elem. anal.;

in diethyl ether addn. of the allene to the Cr complex, 3 h at 50°C; characterization by (1)H-NMR in mixture (decompn. by chromy.);