Asymmetric Hydrogenation of β-Aryl Alkylidene Malonate Esters: Installing an Ester Group Significantly Increases the Efficiency

Acid cleavage of the acetoxy epoxide IIIa with aqueous perchloric acid or hydrobromic acid gave two types of products, i.e. the diol Va or the bromohydrin VIa, and the cyclic ether VIII. The latter compound arises by participation of ether oxygen of the ester group. On reaction with perchloric acid the epoxide IVa gave the diol XIIIa as a product of a normal reaction and the isomeric diol Xa as a product arising by intramolecular participation of the carbonyl oxygen of the 19-acetoxy group. Participation of the 19-ester group is confirmed by the formation of the cyclic carbonate XI when the 19-carbonate IVb is treated analogously. On reaction with hydrobromic acid, the epoxide IVa gave solely the bromohydrin XIVa as a product of the normal reaction course. Discussed is the similarity of these reactions with electrophilic additions to the related 19-acetoxy olefins I and II, the mechanism, the difference in behavior of both epoxides III and IV, the dependence of the product ratio on the nucleophility of the attacking species, and the competition between participation of an ambident neighboring group and an external nucleophile attack.

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Chiral Diphosphites as Ligands for the Rhodium- and Iridium-Catalysed Asymmetric Hydrogenation: Precatalyst Complexes, Intermediates and Kinetics of the Reaction

European Journal of Inorganic Chemistry ◽

10.1002/(sici)1099-0682(200006)2000:6<1287::aid-ejic1287>3.3.co;2-g ◽

2000 ◽

Vol 2000 (6) ◽

pp. 1287-1294 ◽

Cited By ~ 17

Author(s):

Oscar Pàmies ◽

Gemma Net ◽

Aurora Ruiz ◽

Carmen Claver

Keyword(s):

Asymmetric Hydrogenation ◽

Kinetics Of

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Reaction Mechanisms of Inorganic and Organometallic Systems

10.1093/oso/9780195301007.001.0001 ◽

2007 ◽

Author(s):

Robert B. Jordan

Keyword(s):

Electron Transfer ◽

Heterogeneous Systems ◽

Asymmetric Hydrogenation ◽

Pressure Effects ◽

General Level ◽

Hydrogenation Catalysts ◽

Methyl Transferase ◽

Transfer Region ◽

Previous Edition ◽

Oxide Synthase

This third edition retains the general level and scope of earlier editions, but has been substantially updated with over 900 new references covering the literature through 2005, and 140 more pages of text than the previous edition. In addition to the general updating of materials, there is new or greatly expanded coverage of topics such as Curtin-Hammett conditions, pressure effects, metal hydrides and asymmetric hydrogenation catalysts, the inverted electron-transfer region, intervalence electron transfer, photochemistry of metal carbonyls, methyl transferase and nitric oxide synthase. The new chapter on heterogeneous systems introduces the basic background to this industrially important area. The emphasis is on inorganic examples of gas/liquid and gas/liquid/solid systems and methods of determining heterogeneity.

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Synthesis of Spiro Diphosphines and Their Application in Asymmetric Hydrogenation of Ketones

Journal of the American Chemical Society ◽

10.1021/ja029907i ◽

2003 ◽

Vol 125 (15) ◽

pp. 4404-4405 ◽

Cited By ~ 193

Author(s):

Jian-Hua Xie ◽

Li-Xin Wang ◽

Yu Fu ◽

Shuo-Fei Zhu ◽

Bao-Min Fan ◽

...

Keyword(s):

Asymmetric Hydrogenation

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