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。
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
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。
Alternatives to Phosphinooxazoline (<i>t-</i>
BuPHOX) Ligands in the Metal-Catalyzed Hydrogenation of Minimally Functionalized Olefins and Cyclic β-Enamides
privileged 4‐alkyl‐2‐[2‐(diphenylphosphino)phenyl]‐2‐oxazoline (PHOX) ligands by replacing the phosphine moiety by a biaryl phosphite group and/or the introduction of a methylene spacer between the oxazoline and the phenyl ring. The modular design of the ligands has given us the opportunity not only to overcome the limitations of the iridium‐PHOX catalytic systems in the hydrogenation of minimally functionalized
Indene Derived Phosphorus‐Thioether Ligands for the Ir‐Catalyzed Asymmetric Hydrogenation of Olefins with Diverse Substitution Patterns and Different Functional Groups
作者:Jèssica Margalef、Maria Biosca、Pol Cruz‐Sánchez、Xisco Caldentey、Carles Rodríguez‐Escrich、Oscar Pàmies、Miquel A. Pericàs、Montserrat Diéguez
DOI:10.1002/adsc.202100069
日期:2021.10.5
ether ligands have been tested in the Ir-catalyzedasymmetrichydrogenation of a range of olefins (50 substrates in total). The presented ligands are synthesized in three steps from cheap indene and they are air-stable solids. Their modular architecture has been crucial to maximize the catalytic performance for each type of substrate. Improving most Ir-catalysts reported so far, this ligand family
已经在 Ir 催化的一系列烯烃(总共 50 个底物)的不对称氢化中测试了一系列亚磷酸酯/亚膦酸酯 - 硫醚配体。所提出的配体是由廉价的茚分三步合成的,它们是空气稳定的固体。它们的模块化结构对于最大化每种类型底物的催化性能至关重要。改进了迄今为止报道的大多数 Ir 催化剂,该配体家族呈现出更广泛的底物范围,涵盖具有不同官能团的不同取代模式,范围从未官能化的烯烃,到具有较差配位基团的烯烃,再到具有配位官能团的烯烃。α,β-不饱和无环和环状酯、酮和酰胺以 83% 到 99% ee 的对映选择性氢化。对于具有挑战性的底物,例如未官能化的 1,1'-二取代烯烃、官能化的三和 1,1'-二取代乙烯基膦酸酯和 β-环状烯酰胺,也实现了 91% 至 98% ee 的对映选择性。当使用环境友好的 1,2-碳酸亚丙酯作为溶剂时,Ir-配体组件的催化性能得以保持。