A Mixed-Ligand Approach Enables the Asymmetric Hydrogenation of an α-Isopropylcinnamic Acid en Route to the Renin Inhibitor Aliskiren was written by Boogers, Jeroen A. F.;Felfer, Ulfried;Kotthaus, Martina;Lefort, Laurent;Steinbauer, Gerhard;De Vries, Andre H. M.;De Vries, Johannes G.. And the article was included in Organic Process Research & Development in 2007.Recommanded Product: 864529-90-8 This article mentions the following:
An asym. hydrogenation of (E)-2-isopropyl-3-[3-(3-methoxypropoxy)-4-methoxyphenyl]-2-propenoic acid, which affords a chiral intermediate for the renin inhibitor aliskiren, has been developed using a rhodium catalyst ligated with a chiral monodentate phosphoramidite and a nonchiral phosphine. Whereas catalysts based on two equivalent of monodentate phosphoramidites gave promising results, the rate of hydrogenation and ee of the product could be improved spectacularly by the addition of monodentate nonchiral triarylphosphines to these catalysts. This remarkable mixed-ligand catalyst has been identified using high-throughput experimentation. With the best catalysts turnover numbers >5000 mol mol-1, turnover frequencies >1000 mol mol-1 h-1, and ee’s up to 95% have been achieved. In the experiment, the researchers used many compounds, for example, 1-((11bR)-2,6-Dimethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-yl)piperidine (cas: 864529-90-8Recommanded Product: 864529-90-8).
1-((11bR)-2,6-Dimethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-yl)piperidine (cas: 864529-90-8) belongs to chiral phosphine ligands. Although many reactions require more nucleophilic trialkylphosphines as catalysts, only a few chiral trialkylphosphines are available. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.Recommanded Product: 864529-90-8
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis