Alame, Mohamad published the artcileExtensive re-investigations of pressure effects in rhodium-catalyzed asymmetric hydrogenations, COA of Formula: C38H24F4O4P2, the publication is Advanced Synthesis & Catalysis (2008), 350(6), 898-908, database is CAplus.
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.
Advanced Synthesis & Catalysis published new progress about 503538-69-0. 503538-69-0 belongs to dioxole, auxiliary class (Atropisomeric Bisphosphine Ligands, name is (R)-5,5′-Bis(diphenylphosphino)-2,2,2′,2′-tetrafluoro-4,4′-bi-1,3-benzodioxole, and the molecular formula is C38H24F4O4P2, COA of Formula: C38H24F4O4P2.
Referemce:
https://en.wikipedia.org/wiki/1,3-Benzodioxole,
Dioxole | C3H4O2 – PubChem