A positive nonlinear effect in catalytic asymmetric cyclopropanation of styrene with ethyl diazoacetate

The existence of a positive nonlinear effect [(+)-NLE] in the asymmetric cyclopropanation of styrene with ethyl diazoacetate catalysed by a chiral Cu(I)–bisoxazoline complex was observed. This effect can be explained by the possible formation of a catalytically inactive heterochiral meso-complex.