Cu(acac)2, Ph3PCuX, Cu(O2CCF3)2 etc copper complexes were used to catalyze the reaction of cyclopropanation of tetramethylethene with ethyldiazoacetate. The stronger the ligand electroaffinity and the lower the sterohandicap of the ligands, the stronger the catalytic activity of their copper complexes. The activity of Cu(O2CCF3)2 and the temperature of the reaction were studied. The active center of the catalysts was crefully researched and it was proved to be a one-valence copper complex. Inducation period is because of the time necessary of the copper (II) to be reduced into copper (I) which is active species for EDA. The mechanism of this reaction was thought by means of metal carbene (A cycle).

Key words: REACTION MECHANISM, ALKENE, CATALYTIC ACTIVITY, TETRAMETHYL-ETHYLENE