Optically Active Amine Derivatives: Ruthenium-Catalyzed Enantioselective Hydrogenation of Enamides
作者:P. Dupau、P. Le Gendre、C. Bruneau、P. H. Dixneuf
DOI:10.1055/s-1999-2937
日期:1999.11
Enamides have first been prepared by reaction of 5-methoxy-3-chromanone and 2-tetralone with primary amides under acidic conditions. The enantioselectivities observed in the asymmetric hydrogenation of these enamides using ruthenium catalysts strongly depended on both the starting ketone and the nature of the amide group.
reducing alkenes bearing metal-coordinating groups. In the present system, selectivity was pressure-dependent: In most cases, a decrease in the H2 pressure to 3 bar resulted in an increase in enantioselectivity. Moreover, the process can be carried out in environmentally friendly solvents, such as methanol and ethyl acetate, with no loss of selectivity.
MaxPHOX-Ir 催化剂系统为 α-和 β-四氢萘酮衍生的环状烯酰胺的还原提供了迄今为止报道的最高选择性。该结果表明铱催化剂也能有效还原带有金属配位基团的烯烃。在本系统中,选择性取决于压力:在大多数情况下,氢气压力降低至 3 bar 会导致对映选择性增加。此外,该过程可以在甲醇和乙酸乙酯等环保溶剂中进行,而不会损失选择性。
Ruthenium-Catalysed Enantioselective Hydrogenation of Trisubstituted Enamides Derived from 2-Tetralone and 3-Chromanone: Influence of Substitution on the Amide Arm and the Aromatic Ring
作者:J. L. Renaud、P. Dupau、A.-E. Hay、M. Guingouain、P. H. Dixneuf、C. Bruneau
DOI:10.1002/adsc.200390017
日期:2003.1
Cyclic enamides were prepared in one step from tetralone and chromanone derivatives and primary amides under acidic conditions. The enantioselectivehydrogenation of these enamides bearing an endocyclic trisubstituted carbon-carbon double bond was performed at room temperature in the presence of ruthenium catalysts. On the one hand, the nature of the amide group had little influence on the enantioselectivity
Phosphite-Thiother Ligands Derived from Carbohydrates allow the Enantioswitchable Hydrogenation of Cyclic β-Enamides by using either Rh or Ir Catalysts
Phosphite‐thioether ligands with a simple modular architecture, derivedfrom inexpensive l‐(+)‐tartaric acid and d‐mannitol, have been for the first time successfully applied (ee values up to 99 %) in the synthesis of 2‐aminotetralines and 3‐aminochromanes by metal‐catalyzed asymmetric hydrogenation of cyclic β‐enamides. The ligands have the advantages of the robustness of the thioether/phosphite moieties
Rhodium-P,O-bidentate coordinated ureaphosphine ligands for asymmetric hydrogenation reactions
作者:Jurjen Meeuwissen、Remko J. Detz、Albertus J. Sandee、Bas de Bruin、Joost N. H. Reek
DOI:10.1039/b926043a
日期:——
We present new ureaphosphine ligands that coordinate in a P,O-bidentate fashion to rhodium(I). The ureaphosphine-Rh(I)-complexes were effectively used in the asymmetric hydrogenation of cyclic enamides giving high conversions and enantioselectivity.