a modest 15% enantiomeric excess. Knowles was also the first to apply enantioselective metal catalysis to industrial-scale synthesis; while working for the Monsanto Company he developed an enantioselective hydrogenation step for the production of L-DOPA, utilising the DIPAMP ligand. Noyori devised a copper complex using a chiral Schiff base ligand, which he used for the metal–carbenoid cyclopropanation of styrene. In common with Knowles' findings, Noyori's results for the enantiomeric excess for this first-generation ligand were disappointingly low: 6%. However continued research eventually led to the development of the Noyori asymmetric hydrogenation reaction. Sharpless complemented these reduction reactions by developing a range of asymmetric oxidations (Sharpless epoxidation, Sharpless asymmetric dihydroxylation, Sharpless oxyamination) during the 1970s and 1980s. With the asymmetric oxyamination reaction, using osmium tetroxide, being the earliest. During the same period, methods were developed to allow the analysis of chiral compounds by NMR; either using chiral derivatizing agents, such as Mosher's acid, or europium based shift reagents, of which Eu(DPM)3 was the earliest. Chiral auxiliaries were introduced by E.J. Corey in 1978 and featured prominently in the work of Dieter Enders. Around the same time enantioselective organocatalysis was developed, with pioneering work including the Hajos–Parrish–Eder–Sauer–Wiechert reaction. Enzyme-catalyzed enantioselective reactions became more and more common during the 1980s, particularly in industry, with their applications including asymmetric ester hydrolysis with pig-liver esterase. The emerging technology of genetic engineering has allowed the tailoring of enzymes to specific processes, permitting an increased range of selective transformations. For example, in the asymmetric hydrogenation of statin precursors. See also Aza-Baylis–Hillman reaction, for the use of a chiral ionic liquid in enantioselective synthesis Kelliphite, a chiral ligand widely used in asymmetric synthesis Spontaneous absolute asymmetric synthesis, the synthesis of chiral products from achiral precursors and without the use of optically active catalysts or auxiliaries. It is relevant to the discussion homochirality in nature. Tacticity, a property of polymers which originates from enantioselective synthesis Chiral analysis Enantioselective analysis References Chemical synthesis Stereochemistry Asymmetry