| Research Abstract |
Hydrogenation of unsaturated organic molecules such as olefins and ketones is one of the simplest and basic organic reaction. The chiral version realizing general stereocontrol of tertiary stereogenic carbon atoms is undoubtedly desirable. Particularly homogeneous asymmetric hydrogenation catalyzed by transition metal complexes provides an ideal way to multiply chirality and to produce large amounts of chiral compounds of either absolute configuration with a very small quantity of chiral source. Proper combination of selected central metals and well-designed chiral ligands is the most important requirement for high efficiency. Our invention of rhodium(I) and ruthenium(II) complexes containing an originally designed atropisomeric chiral bis(triaryl)phosphine, 2,2'-bis(diarylphosphino)-1,1'-binaphthyl(BINAP), has opened a new era in stereoselective hydrogenation. A wide range of olefinic and ketonic substrates can be smoothly hydrogenated in an enantioselective manner. A variety of terpenes, vitamins, beta-lactam antibiotics, alpha-and beta-amino acids, alkaloids, and other compounds of biological interest are accessible by this method. Some important chiral compounds thus prepared include antiinflammatory naproxen, isoquinoline alkaloids such as morphine, benzomorphans, and morphinans, citronellol, vitamin E and K_1, intermediates of 1beta-methylcarbapenems, prostaglandins, statine series, carnitine, GABOB, and compactin intermediates. This asymmetric hydrogenation is very clean, operationally simple, economical, and capable of being conducted on any scale with a substantially high substrate/catalyst ratio and very high substrate concentration in organic solvents. This method, therefore, is not only useful for laboratory preparation of optically active substances but also powerful even on an industrial level. The BINAP-Ru catalyzed hydrogenation of racemic methyl alpha-(benzamidomethyl)acetoacetate (dynamic kinetic resolution) is indeed used for an industrial
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