[2.2]Paracyclophane derivatives in asymmetric catalysis

The use of paracyclophane derivatives in asymmetric catalysis was surveyed. It was found that to date, a rather limited range of cyclophane ligands has been applied to a fairly wide variety of catalytic oxidations, reductions, and carbon-carbon bond-forming reactions, producing yields and selectivities that range from modest to excellent. Monosubstituted paracyclophane ligands have formed catalysts that are only modestly selective. In contrast, disubstituted cyclophanes with substituents either on the same ring or on different rings have formed some very selective classes of catalyst. The reactions investigated to date suggest that the creation of cyclophanes bearing chiral substituents leads to an interesting interplay between the planar chirality of the cyclophane and the chirality of the substituent.