S. Kanemasa et al., C-2-SYMMETRICAL 1,2-DIAMINE COPPER(II) TRIFLUOROMETHANESULFONATE COMPLEXES AS CHIRAL CATALYSTS - ASYMMETRIC CYCLOPROPANATIONS OF STYRENE WITH DIAZO ESTERS/, Tetrahedron letters, 35(43), 1994, pp. 7985-7988
Styrene and diazo esters react in the presence of copper(II) trifluoro
methanesulfonate (1 mol%) and '-di(mesitylmethyl)-1,2-diphenyl-1,2-eth
anediamine (2 - 3 mol%) to give 2-phenyl-1-cyclopropanecarboxylates in
good to excellent optical yields. This reaction has been applied to t
he synthesis of chrythanthemic acid.