Ligands & Organocatalysts
A ligand comprises hetero atoms, carbenes, or unsaturated bonds in its molecule, and is coordinated with a metal to form a complex. If a ligand is bulky or exhibits high electron density, it improves the turnover frequency (TOF) of a reaction. If stereoselectivity in the reaction field around a metal complex is controlled by using a bulky ligand, a highly selective reaction is possible. FUJIFILM Wako deal with phosphine and carbene ligands that are applicable to a wide range of reactions.
In addition, organometallic catalysts are used for a wide range of asymmetric syntheses; however, in some cases, catalysts tend to be unstable and expensive, with trace amounts of metal catalysts remaining in the target compound. Organic catalysts, which do not contain any metals, are attracting attention for addressing these problems. Organic catalysts are considered environmentally friendly because they do not produce harmful metal wastes. Maruoka Catalyst is a chiral phase-transfer catalyst that is optimal for the asymmetric synthesis of α-amino acids having various side chains.