Alame, Mohamad; Pestre, Nathalie; de Bellefon, Claude published the article 《Extensive re-investigations of pressure effects in rhodium-catalyzed asymmetric hydrogenations》. Keywords: pressure effect rhodium catalysis asym hydrogenation.They researched the compound: (R)-2,2′,6,6′-Tetramethoxy-4,4′-bis(diphenylphosphino)-3,3′-bipyridine( cas:221012-82-4 ).HPLC of Formula: 221012-82-4. Aromatic heterocyclic compounds can be divided into two categories: single heterocyclic and fused heterocyclic. In addition, there is a lot of other information about this compound (cas:221012-82-4) here.
The catalytic hydrogenation of three prochiral substrates Me Z-α-acetamidocinnamate (MAC), Me 2-acetamidoacrylate (M-Acrylate) and Et 4-methyl-3-acetamido-2-propanoate (E-EMAP) with rhodium precursors complexed with chiral diphosphines is reported at 1-30 bar hydrogen pressure. A library of 56 chiral diphosphines, including 23 BINAP derivatives, 7 JOSIPHOS, 5 BIPHEP, 3 DUPHOS derivatives, and 18 other ligands, was used. While it was generally accepted that high hydrogen pressure would result in lower ees, it is now demonstrated on a statistical basis that an equivalent distribution between beneficial and detrimental pressure effects on ee prevails and that the hydrogen pressure effect on enantioselectivity is not an isolated phenomenon since more than 33% of the reaction systems studied are strongly affected. In some case, the enantioselectivity can be improved up to 97% just by applying a higher hydrogen pressure. Extension of these conclusions to other non-chiral reagents is proposed.
In addition to the literature in the link below, there is a lot of literature about this compound((R)-2,2′,6,6′-Tetramethoxy-4,4′-bis(diphenylphosphino)-3,3′-bipyridine)HPLC of Formula: 221012-82-4, illustrating the importance and wide applicability of this compound(221012-82-4).
Reference:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider