Synthesis and Use in Asymmetric Hydrogenations of Solely Planar Chiral 1,2-Disubstituted and 1,2,3-Trisubstituted Ferrocenyl Diphosphines: A Comparative Study
摘要:
A total of 12 enantiopure 1,2-disubstituted and 1,2,3-trisubstituted ferrocenyl diphosphines [1-Ph2P-2-R2PCH2-3-R'-Fc, R = Cy, t-Bu, 3,5-(CH3)(2)C6H3), R' = H, CH3, Ph, 3,5-(CH3)(2)C6H3)] have been synthesized, characterized, and tested in asymmetric rhodium- and ruthenium-catalyzed hydrogenations of four alkenes and two ketones. The performance of these ferrocene derivatives in catalytic hydrogenations was compared to those of catalysts based on Josiphos, PPF-t-Bu-2, and Xyliphos [1-Ph2P-2-R2P(CH3)CH-Fc, R = Cy, t-Bu, 3,5-(CH3)(2)C6H3)]. Dichloro palladium(II) complexes of Xyliphos and its analogues lacking the stereogenic center were synthesized as model compounds, and their molecular structures were studied in solution and, for four complexes, in the solid state. In hydrogenation reactions the replacement of Xyliphos as the catalyst ligand with its analogues lacking the stereogenic center leads to changes in product configurations or significant increases or decreases in ee values.
Catalytic Enantioselective Synthesis of Cyclobutenes from Alkynes and Alkenyl Derivatives
作者:Mahesh M. Parsutkar、Vinayak Vishnu Pagar、T. V. RajanBabu
DOI:10.1021/jacs.9b07885
日期:2019.9.25
compounds from readily available precursors, using scalable and environmentally benign chemistry, can greatly impact their design, synthesis and eventually manufacture on scale. Functionalized cyclobutanes and cyclobutenes are important structural motifs seen in many bioactive natural products and pharmaceutically relevant small molecules. They are also useful precursors for other classes of organic compounds
使用可扩展且环境友好的化学方法,发现用于从容易获得的前体制备手性化合物的对映选择性催化反应,可以极大地影响它们的设计、合成和最终的规模制造。功能化环丁烷和环丁烯是许多生物活性天然产物和药学相关小分子中的重要结构基序。它们也是其他类别有机化合物的有用前体,例如其他环烷烃衍生物、杂环化合物、立体定义的 1,3-二烯和催化不对称合成的配体。制造环丁烯的最简单方法是通过炔烃和烯基衍生物之间的对映选择性 [2+2]-环加成反应,这种反应历史悠久。然而,给出可接受的对映选择性的此类已知反应的范围非常窄,并且严格限于活化的炔烃和高反应性烯烃。在这里,我们公开了一种广泛适用的对映选择性 [2+2]-环加成反应,在各种炔烃和烯基衍生物(两种最丰富的有机前体类别)之间进行。关键的环加成反应使用衍生自易于合成的配体和地球上丰富的金属钴的催化剂。记录了 50 多种对映选择性在 86-97% ee 范围内的不同
Tunable ferrocenyl diphosphine ligands for the Ir-catalyzed enantioselective hydrogenation of N-aryl imines
Ferrocenyl diphosphines R2PF-P(R′)2 are effective, tunable ligands for the iridium catalyzed enantioselectivehydrogenation of N-aryl imines in the presence of iodide and acid promoters. Structure–activity/selectivity correlations were found for the hydrogenation of N-(2-ethyl-6-methylphenyl)-N-(1′-methoxymethyl)-ethylidene-amine (MEA-imine) and for 2,3,3-trimethylindolenine (TMI). Extremely high catalytic
Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Rhenium Complexes with Chiral Ferrocenylphosphane Ligands
作者:Esteban Mejía、Raphael Aardoom、Antonio Togni
DOI:10.1002/ejic.201200693
日期:2012.11
rhenium complexes containing chiral ferrocenyldiphosphane ligands of the Josiphos family, starting from commercially available rhenium sources. These new ReV oxido and nitrido complexes, several of which have been characterized by X-ray crystallography, are air- and moisture-stable and are active catalysts in the asymmetric transfer hydrogenation of ketones using 2-propanol as the hydrogen source in
The new clusters [H4Ru4(CO)10(μ‐1,2‐P‐P)], [H4Ru4(CO)10(1,1‐P‐P)] and [H4Ru4(CO)11(P‐P)] (P‐P=chiral diphosphine of the ferrocene‐based Josiphos or Walphos ligand families) have been synthesised and characterised. The crystal and molecular structures of eleven clusters reveal that the coordination modes of the diphosphine in the [H4Ru4(CO)10(μ‐1,2‐P‐P)] clusters are different for the Josiphos and the
Asymmetric hydrogenation of an α-unsaturated carboxylic acid catalyzed by intact chiral transition metal carbonyl clusters – diastereomeric control of enantioselectivity
作者:Ahmed F. Abdel-Magied、Yusuf Theibich、Amrendra K. Singh、Ahibur Rahaman、Isa Doverbratt、Arun K. Raha、Matti Haukka、Michael G. Richmond、Ebbe Nordlander
DOI:10.1039/c9dt04799a
日期:——
Asymmetric hydrogenation catalysis by [(μ-H)2Ru3(μ3-S)(CO)7(μ-P–P*)] (P–P* = chiral diphosphine) indicates intact chiral clusters as active catalysts.