Brønsted Acid-Catalyzed, Highly Enantioselective Addition of Enamides to In Situ<i>-</i>Generated<i>ortho</i>-Quinone Methides: A Domino Approach to Complex Acetamidotetrahydroxanthenes
作者:Satyajit Saha、Christoph Schneider
DOI:10.1002/chem.201406044
日期:2015.2.2
The highly enantioselective conjugate addition of enamides and enecarbamates to in situ‐generated ortho‐quinone methides, upon subsequent N,O‐acetalization, gives rise to acetamido‐substituted tetrahydroxanthenes with generally excellent enantio‐ and diastereoselectivities. A chiral BINOL‐based phosphoric acid catalyst controls the enantioselectivity of the carbon–carbon bond‐forming event. The products
Asymmetric Hydrogenation Using Rhodium Complexes Generated from Mixtures of Monodentate Neutral and Anionic Phosphorus Ligands
作者:Dominik J. Frank、Axel Franzke、Andreas Pfaltz
DOI:10.1002/chem.201202408
日期:2013.2.11
anionic phosphorus ligands was synthesized and evaluated in the asymmetric rhodium‐catalyzedhydrogenation of functionalizedolefins by using either catalysts containing identical ligands or catalysts generated from mixtures of two different ligands. We expected that the combination of an anionic ligand with a neutral ligand would favor the formation of hetero over homo bis‐ligand complexes due to charge
WingPhos, a C2‐symmetric bisphosphorus ligand with a deep and well‐defined chiral pocket was developed. It has shown high efficiency in the rhodium‐catalyzed asymmetrichydrogenation of (E)‐β‐aryl‐N‐acetyl enamides, cyclic β‐aryl enamides, and heterocyclic β‐aryl enamides. A series of chiral β‐arylisopropylamines, 2‐aminotetralines, and 3‐aminochromans can be synthesized with excellent ee values (nbd=3
WingPhos是一种C 2对称的双磷配体,具有较深且定义明确的手性口袋。在(E)-β-芳基-N-乙酰基酰胺,环状β-芳基酰胺和杂环β-芳基酰胺的铑催化不对称氢化反应中显示出很高的效率。可以合成一系列具有良好ee值(nbd = 3,5-降冰片二烯; TON =周转数)的手性β-芳基异丙胺,2-氨基四氢呋喃和3-氨基苯并二氢吡喃。
UREAphos: supramolecular bidentate ligands for asymmetric hydrogenation
作者:Albertus J. Sandee、Alida M. van der Burg、Joost N. H. Reek
DOI:10.1039/b614571j
日期:——
Supramolecular bidentate phosphite ligands are presented as a new class of ligands for rhodium catalysed asymmetrichydrogenation.
超分子的二齿亚磷酸酯亚磷酸酯配体作为铑催化的不对称氢化的一类新的配体被提出。
Asymmetric Hydrogenation of Disubstituted, Trisubstituted, and Tetrasubstituted Minimally Functionalized Olefins and Cyclic β-Enamides with Easily Accessible Ir–P,Oxazoline Catalysts
We have developed a family of Ir–P,oxazoline catalysts for asymmetrichydrogenation. These catalysts, with a simple modular architecture, have shown a high tolerance to the olefin geometry and substitution pattern, and to the presence of several neighboring polar groups. Thus, they were able to successfully hydrogenate disubstituted, trisubstituted, and tetrasubstituted minimally functionalized olefins