US Patent 7256302 Substituted paracyclophane derivatives in asymmetric catalysis

A substituted paracyclophane is described of formula (I) wherein X1 and X2 are linking groups comprising between 2 to 4 carbon atoms, Y1 and Y2 are selected from the group consisting of hydrogen, halide, oxygen, nitrogen, alkyl, cycloalkyl, aryl or heteroaryl, Z1, Z2 and Z3 are substituting groups that optionally contain functional groups, a, b, c, d, e and f are 0 or 1 and a+b+c+d+e+f=1 to 6. Preferably X1 and X2 are —(C2H4)— and a+b+c+d+e+f=1 or 2. The substituted paracyclophane provides transition metal catalysts that demonstrate high activity and selectivity for asymmetric reactions