Driving Enantioselectivity by actuating from strong to very weak organometallic bonds

An excursus on our work in the field of stereoselective homogeneous catalysis will be made starting from classical mono- and C1 and C2 symmetric di-phosphanes to end with a singular D2 symmetric tetra-phosphane. The most characteristic feature of these ligands is electronic tunability, achieved by taking advantage of the different electronic properties of the five-membered aromatic heterocycles used to build the scaffold bearing the phosphorous atom. Phosphorous electronic availability affects the strength of the metal-donor atom bond, which is a crucial parameter influencing the reaction mechanism and, by consequence, kinetics and stereoselectivity. Strong bonds are highly performing in hydrogenation of prostereogenic C=C and C=O double bonds, while weaker bonds are ideal in stereoselective C-C bond forming reactions. Very weak bonds are expectedly ineffective. A deviation from this assumption was highlighted in the case of "inherently chiral" ionic liquids (ICILs), a new class of chiral ionic liquids in which the stereogenic element responsible for chirality coincides with the molecular portion responsible for their specific properties as ionic liquids. Charged metal surfaces strongly influence the supramolecular organizations of an achiral ionic liquid in contact with him through electrostatic interactions and the presence of an ICIL in infinitesimal amounts induces strong chiral reorganization of the whole layer endowing it with impressive enantiorecognition properties.