Enantioselective Enolate Protonation with Chiral Anilines: Scope, Structural Requirements, and Mechanistic Implications
作者:E. Vedejs、A. W. Kruger、N. Lee、S. T. Sakata、M. Stec、E. Suna
DOI:10.1021/ja994437m
日期:2000.5.1
substitution at the γ-carbon, γ-protonation can be a competing reaction in the case of the aliphatic substrates 12, 14b, 14d, and 18. The evidence is most consistent with a mechanism that involves proton transfer from 1a to a mixed aggregate consisting of enolate 4a and the lithiated amide 5, but direct proton transfer from 1a to the enolate is not ruled out.
Stereochemical control by carboxylate groups in homogeneous hydrogenation
作者:John M. Brown、Stephen A. Hall
DOI:10.1016/0022-328x(85)87378-2
日期:1985.4
The stereochemistry of hydrogenation of a range of unsaturated cyclohexanecarboxylic acids and their esters has been investigated, employing either bis(1,4-diphenylphosphino)butanerhodium or pyridine(tricyclohexylphosphine)iridium based cationic catalysts in CH2Cl2. For methyl 3-methylcyclohex-2-enecarboxylate, highly selective reduction to the trans-product was achieved in both cases, whereas the