(Z)-1,2-dibromoethylene; tetrakis(triphenylphosphine) palladium(0) in tetrahydrofuran 16 h; Ambient temperature;

in tetrahydrofuran addn. of a mixt. of (E)- and (Z)-1,2-dibromoethylene in THF to the Pd-complex (room temp.), crystn. (after 0.5 h); no react. of the (Z)-compd.; filtration, washing (THF), drying; elem. anal.; dibromobis(triphenylphosphine)palladium(II) from the mother liquor (after 24 h separation);

zinc in ethanol

tetrabutylammonium fluoride; water T=100°C;

T=49°C; Isomerisierung; Rate constant;

ethanol; bromine

T=300 - 400°C; decomposition;

hydrogen fluoride; hexachloromelamine T=0 - 10°C; 2.5 h; Product distributionMechanism;