78638-64-9Relevant articles and documents
Cationic NHC-Phosphine Iridium Complexes: Highly Active Catalysts for Base-Free Hydrogenation of Ketones
Quan, Xu,Kerdphon, Sutthichat,Peters, Bram B. C.,Rujirawanich, Janjira,Krajangsri, Suppachai,Jongcharoenkamol, Jira,Andersson, Pher G.
, p. 13311 - 13316 (2020/09/22)
Novel bidentate N-heterocyclic carbene-phosphine iridium complexes have been synthesized and evaluated in the hydrogenation of ketones. Reported catalytic systems require base additives and, if excluded, need elevated temperature or high pressure of hydrogen gas to achieve satisfactory reactivity. The developed catalysts showed extremely high reactivity and good enantioselectivity under base-free and mild conditions. In the presence of 1 mol % catalyst under 1 bar hydrogen pressure at room temperature, hydrogenation was complete in 30 minutes giving up to 96 % ee. Again, this high reactivity was achieved in additive-free conditions. Mechanistic experiments demonstrated that balloon pressure of hydrogen was sufficient to form the activate species by reducing and eliminating the 1,5-cyclooctadiene ligand. The pre-activated catalyst was able to hydrogenate acetophenone with 89 % conversion in 5 min.
Stereospecific oxygen rearrangement in the reduction of optically pure methyl mandelate to phenylethanol isomers
Angelis,Smonou
, p. 488 - 490 (2007/10/03)
The reduction of methyl (S)-(+)-mandelate, 1, produces the expected 2-phenylethanol, 3, and the unexpected optically pure 1-phenylethanol, 6, by a stereospecific oxygen atom metathesis; which occurs through a styrene oxide intermediate, whose concentration varies with solvent polarity.
