98-52-2Relevant articles and documents
UNUSUAL HIGH REACTIVITIES OF 5α- AND 5β-CHOLESTAN-3-ONES IN THE HYDROGENATION CATALYZED BY PALLADIUM. EVIDENCE FOR AN ATTRACTIVE INTERACTION OF THE STEROID α-FACE WITH PALLADIUM
Nishimura, Shigeo,Murai, Mikio,Shiota, Michio
, p. 1239 - 1242 (1980)
5α- And 5β-cholestan-3-ones are 30 and 17 times as reactive as 4-t-butylcyclohexanone in Pd catalyzed competitive hydrogenation in t-BuOH.The high reactivity of the steroid ketones and unusual hydrogenation stereochemistry on Pd have been explained on the basis of an attractive interaction of the steroid α-face with Pd.
A direct conversion of aldohexopyranose to ketohexopyranose benzyl derivatives by Meerwein-Ponndorf/Oppenauer reaction induced by air-oxidised samarium diiodide
Adinolfi, Matteo,Iadonisi, Alfonso,Mangoni, Lorenzo
, p. 5987 - 5988 (1996)
2,3,4,6-tetra-O-benzyl-D-galactopyranose and 2,3,4,6-tetra-O-benzyl-D-glucopyranose can be reduced at C-1 and oxidised at C-5 to give 1,3,4,5-tetra-O-benzyl-L-tagatopyranose and 1,3,4,5-tetra-O-benzyl-L-sorbopyranose, respectively, in good yields, through an intramolecular M-P/O reaction induced by preoxidised samarium diiodide.
Postsynthetic Modification of Half-Sandwich Ruthenium Complexes by Mechanochemical Synthesis
Jia, Wei-Guo,Zhi, Xue-Ting,Li, Xiao-Dong,Zhou, Jun-Peng,Zhong, Rui,Yu, Haibo,Lee, Richmond
, p. 4313 - 4321 (2021/05/04)
A mild and environmentally friendly method to synthesize half-sandwich ruthenium complexes through the Wittig reaction between an aldehyde-tagged half-sandwich ruthenium complex and phosphorus ylide mechanochemically is reported herein. The mechanochemical synthesis of valuable half-sandwich ruthenium complexes resulted in a fast reaction, good yield with simple workup, and the avoidance of harsh reaction conditions and organic solvents. The synthesized half-sandwich ruthenium complexes exhibited high catalytic activity for transfer hydrogenation of ketones using 2-propanol as the hydrogen source and solvent. Density functional theory was carried out to propose a mechanism for the transfer hydrogenation process. The modeling suggests the importance of the labile p-cymene ligand in modulating the reactivity of the catalyst.
Base-free transfer hydrogenation of aryl-ketones, alkyl-ketones and alkenones catalyzed by an IrIIICp* complex bearing a triazenide ligand functionalized with pyrazole
Medrano-Castillo, Layla J.,Collazo-Flores, Miguel á.,Camarena-Díaz, Juan P.,Correa-Ayala, Erick,Chávez, Daniel,Grotjahn, Douglas B.,Rheingold, Arnold L.,Miranda-Soto, Valentín,Parra-Hake, Miguel
, (2020/03/13)
An IrIIICp* complex (2) bearing a triazenide ligand functionalized with pyrazole was synthesized and fully characterized by spectroscopic methods and the structure confirmed by X-ray diffraction studies. The catalytic activity of 2 and the control complex 3, which lacks of pyrazole in its structure, was evaluated in the reduction of aryl-ketones, alkyl-ketones, α,β-unsaturated and γ,δ-unsaturated ketones. The catalytic system, using either 2 or 3, exhibited good to excellent selectivity when tested with ketones and alkenones at 90 °C in 2-propanol as hydrogen source under base-free conditions. Reactivity of 2 in 2-propanol and NaH gave a neutral metal hydride (4) while in the absence of base gave two major cationic hydrides species (5 and 6).
