Modified Raney nickel catalyst hydrogenation

UHV surface analysis, apparatus designs, 36 4-14 see also Ultrahigh vacuum surface analysis mechanisms, 32 313, 319-320 Modified Raney nickel catalyst defined, 32 215-217 hydrogenation, 32 224-229 Modifying technique of catalysts, 32 262-264 Modulated-beam mass spectrometry, in detection of surface-generated gas-phase radicals, 35 148-149 MojFe S CpjfCOlj, 38 352 Molar integral entropy of adsorption, 38 158, 160-161... 

Hoffmann-LaRoche has developed a process that uses R,R-tartaric acid/NaBr modified Raney nickel catalyst in the asymmetric hydrogenation of 160 to give 161 in 100% yield and 90-92% ee (6-100-kg scale) for the synthesis of the intermediate of tetrahydrolipstatin (162), a pancreatic lipase inhibitor (Scheme 12.62).5... 

Fukawa, H., Izumi, Y., Komatsu, S., and Akabori, S. (1962) Studies on modified hydrogenation catalyst. 1. Selective hydrogenation activity of modified Raney nickel catalyst for carbonyl group and C=C double bond. Bull. Chem. Soc. Jpn., 35, 1703-1706. 

Nakagawa, S., Sugimura, T., and Tai, A. (1997) Almost perfect enantio-differentiating hydrogenation of methyl 3-cyclopropyl-3-oxopropion-ate over tartaric acid modified Raney Nickel catalyst, Chem. Lett., %59 - 860. 

Tai, A., Ito, K., and Harada, T. (1981) Stereochemical studies of the hydrogenation with an asymmetrically modified Raney nickel catalyst. The hydrogenation of acetylacetone. Bull Chem. Soc. Jpn. 54, 223 -227. 

Ozaki, H., Tai, A., Kobatake, S., Watanabe, H., and Izumi, Y. (1978) Enantioface-differentiating (asymmetric) hydrogenation of ketoester with modified Raney nickel catalyst (MRNi). XXXI. A comparative study of reaction rates and optical yields. Bull. Chem. Soc. Jpn. 51, 3559- 3563. 

Bartok, M., Wittmann, G.W., Gondos, G., and Smith, G.V. (1987) Homogeneous and heterogeneous catalytic asymmetric reactions. I. As5mimetric hydrogenation of the prochiral C=C bond on a modified Raney nickel catalyst, J. Org. Chem. 52, 1139 -1141. 

Gondos, G., Wittmann, G., Bartok, M., Orr, J.C (1993) Chiral hydrogenation of estrone-3-methyl ether on modified Raney nickel catalysts. Steroids, 58, 533-535. 

Scheme 9.6 Hydrogenation of an alkene in the presence of a heterogeneous tartaric acid-modified Raney nickel catalyst.

This procedure is based on the method of Lindsay and Hauser as modified slightly by Osgerby and Pauson. N,N-dimethyl-aminomethylferrocene methiodide has also been prepared by heating formylferrocene with dimethylamine and hydrogen in the presence of Raney nickel catalyst to give dimethylamino-methylferrocene, which was quaternized with methyl iodide. ... 

One of the important conclusions of the early attempts was that it is fruitful to place the functionality near an optically active support. Already in 1958, Isoda and coworkers reported for the first time the enantioselective hydrogenation with a Raney nickel catalyst modified with optically pure amino acids. Optical yields reported at that time were from low (2.5%) to moderate (36%) values (for references see [12]). Subsequently, in 1963, Izumi and coworkers [100] initiated an extended study of the modified Raney nickel system with TA. As a result of their initial researches, this system was the first heterogeneous chiral catalyst to give high enantioselectivities in the hydrogenation of / -ketoesters (95%) [101,102],... 

An excellent review of the problems of the enantioselective heterocatalytic hydrogenation of prochiral double bonds, covering the literature up to 1970, has been compiled by Izumi57). Raney nickel catalysts modified with chiral amino acids or dipeptides gave only very moderate enantiomeric excesses of between 0 and 10% in the hydrogenation of olefins, carbonyl compounds or oximes 57). Only Raney nickel modified with (S)-tyrosine furnished a higher enantiomeric excess in the products58). 

One hundred and six grams (i mole) of benzaldehyde (Note i) and 107 g. (1 mole) of m-toluidine are mixed in a suitable flask the temperature rises to about 6o° (Notes 2 and 3). The mixture is cooled below 35° in cold water, 200 cc. of ether is added, and the solution is placed in the steel reaction vessel of a high-pressure hydrogenation apparatus.1,2 Eight to ten grams of Raney nickel catalyst (p. 15) is added, the bomb is closed, and hydrogen is admitted up to 1000 lb. pressure (Note 4). The bomb is shaken continuously at room temperature for fifteen minutes (Note 5). The contents are removed, and the bomb is washed out with two 200-cc. portions of ether. After the catalyst has been separated by filtration (Note 6), the ether is removed by distillation and the product is distilled from a modified Claisen flask (Note 7). After a small fore-run the A-benzyl-m-toluidine boils at i53-i57°/4 mm. 3iS-3i7°/76o mm. The yield is 175-185 g. (89-94 per cent of the theoretical amount) (Notes 8 and 9). 

Amidine derivatives are effective dehalogenation inhibitors for the chemoselective hydrogenation of aromatic halonitro compounds with Raney nickel catalysts. The best modifiers are unsubstituted or N-alkyl substituted formamidine acetates and dicyandiamide which are able to prevent dehalogenation even of very sensitive substrates. Our results indicate that the dehalogenation occurs after the nitro group has been completely reduced i.e. as a consecutive reaction from the halogenated aniline. A possible explanation for these observations is the competitive adsorption between haloaniline, nitro compound, reaction intermediates and/or modifier. The measurement of the catalyst potential can be used to determine the endpoint of the desired nitro reduction very accurately. 

In contrast to Raney nickel catalysts ( 3.4.1), heterogeneous hydrogenation catalysts based on Pt, Rh or Pd do not induce asymmetry in the presence of tartaric acid [113, 578], Platinum catalysts modified by cinchona alkaloids 3.1 and 3.2 cause asymmetric hydrogenation of the carbonyl group of a-ketoesters with a high enantiomeric excess (> 90%). From other types of ketones, the enantioselectivities are lower. 

Ketones carrying a sulfone substituent in the -position were subjected to enantioselective hydrogenation of the carbonyl group. With the heterogeneous Raney nickel catalyst, modified with tartaric acid and sodium bromide (see Section 2.3.1.1.), l-methylsulfonyl-2-butanone was reduced to (R)-l-methylsulfonyl-2-butanol, 1-methylsulfonyl-2-heptanone to (R)-l-methylsul-fonyl-2-heptanol, and l-methylsulfonyl-2-deeanone to (/ )-l-methylsulfonyl-2-decanol in 100% yield 67-71% ee51. 

The efficiency of a Raney nickel catalyst for hydrogenation of carbonyl groups is much diminished if the catalyst is treated with 0.1% acetic acid or an amino acid, particularly dibasic amino acids or L-phenylalanine but the efficiency for hydrogenation of C=C double bonds remains unaffected. Thus mesityl oxide was hydrogenated to isobutyl methyl ketone selectively and in good yield but cinnamaldehyde could not be reduced in this way.161 For asymmetric hydrogenation with Raney nickel modified by optically active 2-hydroxy carboxylic acids see Tatsumi et al.162... 

The second point to be mentioned is that, in spite of the particular architecture of the catalytic site located inside the pillared layered structure, the hydrogenation activity and selectivity of B3N and B2N is not drastically modified as compared to conventional Raney nickel catalyst. 

Firstly, the /-piperitone is reduced, by means of a reagent such as lithium aluminium hydride to a mixture of diastereomeric alcohols, l-cis-piperitol (36%) and df-frans-piperitol (64%). This mixture is reduced by a Raney nickel catalyst modified by addition of nickel (II) chloride. The hydrogenation is carried out in isopropanol as solvent at 25 °C and a hydrogen pressure of 60 psig. During hydrogenation, the stereochemistry of the isopropyl group controls the stereochemistry of the other centres. 

Izumi Y., Imaida S., Fukawa H. and Akabori S. (1963) Asymmetric hydrogenation with modified Raney nickel. 1. Studies on modified heterogeneous catalysts. IT, Bull. Chem. Soc. Jpn. 36, 21-25. 

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