The structurally characterized copper complex [(i-Pr(3)TACN)Cu(O2CCF3)(2)] (1) mediates nitrene transfer from PhINTs to olefins to form N-tosylaziridines in good to excellent yields, in catalytic amounts (0.5 mol %) 1 order of magnitude less than is required for other copper catalysts, such as [Cu(acac)(2)]. Nitrene transfer reactivity has also been observed with substituted styrenes, internal and terminal aliphatic olefins, and sulfides, suggesting that 1 may be a general nitrene transfer catalyst for use on organic synthesis.