most common chiral bisoxazoline (box) ligands consist of two identical chiral oxazoline moieties, substituted by a bulky group at the 4-positions, joined by a linker. the ligand is bidentate when the linker is a single carbon unit, but is tridentate (usually meridial) when the linker bears an additional coordinating atom, such as a pyridine nitrogen in the case of pybox ligands. the impact of ligand denticity and active intermediate geometry on the stereochemical outcome has been thoroughly reviewed.