88546-12-7Relevant articles and documents
Mechanistically Guided One Pot Synthesis of Phosphine-Phosphite and Its Implication in Asymmetric Hydrogenation
Sen, Anirban,Kumar, Rohit,Pandey, Swechchha,Vipin Raj,Kumar, Pawan,Vanka, Kumar,Chikkali, Samir H.
, (2022/01/11)
Although hybrid bidentate ligands are known to yield highly enantioselective products in asymmetric hydrogenation (AH), synthesis of these ligands is an arduous process. Herein, a one pot, atom-economic synthesis of a hybrid phosphine-phosphite (L1) is reported. After understanding the reactivity difference between an O-nucleophile versus C-nucleophile, one pot synthesis of Senphos (L1) was achieved (72 %). When L1 was treated with [Rh], 31P NMR revealed bidentate coordination to Rh. Senphos, in the presence of rhodium, catalyzes the AH of Methyl-2-acetamido-3-phenylacrylate and discloses an unprecedented turn over frequency of 2289, along with excellent enantio-selectivity (92 %). The generality is demonstrated by hydrogenating an array of alkenes. The AH operates under mild conditions of 1–2 bar H2 pressure, at room temperature. The practical relevance of L1 is demonstrated by scaling-up the reaction to 1 g and by synthesizing DOPA, a drug widely employed for the treatment of Parkinson's disease. Computational insights indicate that the R isomer is preferred by 3.8 kcal/mol over the S isomer.
Melphalan intermediate and preparation method thereof
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Paragraph 0043; 0050; 0056-0057; 0107; 0114; 0120-0121; 0171, (2019/08/02)
The invention discloses a Melphalan intermediate and a preparation method thereof. The Melphalan intermediate is prepared by acidifying a compound p-nitrobenzaldehyde under the action of methanol, a hydrochloric acid solvent, etc. The preparation method has a route with mild reaction conditions, is higher than an existing preparation method in yield, is economical and effective, and is suitable for large-scale industrial production. The synthesis route is as shown in the description.
Model containing pyridine base crown ether chiral bis-phosphorus ligand and its in asymmetric catalytic application of the catalyst in the reaction (by machine translation)
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Paragraph 0122; 0123; 0124, (2016/10/10)
This invention relates to model containing pyridine base crown ether chiral bis-phosphorus ligand and its application of symmetrical catalytic reaction. Chiral bis-phosphorus ligand and intermediates containing pyridine base crown ether single phosphorus ligand the structural formula of (I) are respectively shown as the following formula, formula (I '). These chiral bis-phosphorus ligand of the transition metal complexes can be used as catalyst for asymmetric reactions, containing pyridine base crown ether of the invention the chiral bis-phosphorus ligand it is a kind of novel chiral ligand capable of regulating, by using different alkali metal ion, alkaline earth metal ion, rare-earth metal ion, ammonium salt or organic amine salt such as a crown ether, on the object with the ligand complex, the catalyst can be realized the space structure and electronic nature of the regulation and control. This kind of the alkali metal ion complexation assembled containing pyridine base crown ether chiral double-phosphorus ligand transition metal (Rh and Ir) complexes in catalytic hydrogenation reaction demonstrate excellent catalytic activity and good stereoselectivity. (by machine translation)
