Asymmetric catalysis: A ligand's eye view

More than ever, synthetic chemists are faced with the requirement of preparing materials in an enantioselective fashion. While there are several options for entering this optically active world, the one with the greatest benefit is the use of asymmetric catalysts. The key feature responsible for the success of these reagents is the chiral ligands that surround the catalytic core and create a chiral environment in which the reaction proceeds. Because the enantioselectivity of these catalysts ultimately can be traced back to the ligands, this review provides an overview of the major classes of ligands and covers the recent developments, both in these existing families as well as in new ones just being reported.