This Account provides an overview of our activities in the area of asymmetric hydrogenation over the last 12 years. We discuss the manufacture of metal-containing precatalysts and their use in asymmetric hydrogenation processes. Many of the metal complexes have been made on a multikilogram scale for our own use and also provided to our customers. In addition, we review some of the applications that we have developed for our asymmetric hydrogenation catalysts, many of which have been operated on commercial scales. This all underlines that asymmetric hydrogenation is a mature technology that has been adopted for use in the pharmaceutical and fine-chemical industries.

A concise enantioselective synthesis of (S)-(+)-3-aminomethyl-5-methylhexanoic acid (1, Pregabalin) has been developed. The key step is the asymmetric hydrogenation of a 3-cyano-5-methylhex-3-enoic acid salt 2 with a rhodium Me-DuPHOS catalyst, providing the desired (S)-3-cyano-5-methylhexanoate 3 in very high ee. Subsequent hydrogenation of the nitrile 3 with a heterogeneous nickel catalyst provides Pregabalin 1 in excellent overall yield and purity.

An extremely efficient route to highly enantiomerically enriched 2-methylsuccinamic acid via asymmetric hydrogenation has been developed. By using [(S,S)-Et-DuPHOS Rh COD]BF 4 as the precatalyst under a set of broadly optimised process parameters, (R)-2-methylsuccinamic acid was obtained in 96% ee at a substrate-to-catalyst ratio (S/C) of 100000 (average turnover frequency ∼13000 h -1 ). The exclusion of chloridecontaining contaminants in the substrate was found to be crucial in obtaining exceptionally low catalyst loadings. This material could be upgraded with a single-crystal digestion to yield (R)-2-methylsuccinamic acid in >99.5% ee containing less than 1 ppm rhodium.

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