111209-96-2Relevant articles and documents
A practical asymmetric conjugate addition to cyclic enones with chiral bifunctional Ru amido catalysts
Dub, Pavel A.,Wang, Hui,Watanabe, Masahito,Gridnev, Ilya D.,Ikariya, Takao
, p. 3452 - 3455 (2012)
A practical asymmetric C-C bond formation to synthetically useful β-chiral cyclic ketones (>99% ee) using bifunctional chiral amido Ru catalysts under an S/C = 1000, the highest ratio achieved so far in the literature for this class of reactions, is descr
Physico-chemical and Catalytic Properties of Ytterbium introduced into Y-Zeolite
Baba, Toshihide,Hikita, Satoru,Koide, Ryutaro,Ono, Yoshio,Hanada, Tomoko et al.
, p. 3177 - 3180 (1993)
Ytterbium was introduced into K(+)-exchanged Y-zeolite (Yb/K-Y) by impregnation from a liquid ammonia solution of the metal, and the change in the chemical state of the metal with evacuation temperature was investigated by infrared (IR), X-ray absorbtion fine structure (XAFS) and X-ray photoelectron (XPS) spectroscopies.When ammonia was removed by brief evacuation at room temperature followed by evacuation at 333 K, the IR spectrum showed the presence of Yb amides.The amide species were observed up to 423 K.The Yb L2-edge X-ray absorbtion near-edge structure (XANES) spectrum showed that the Yb species exist as 16.4percent Yb(II) and 83.6percent Yb(III) after evacuation at 333 K.The fraction of Yb(2+) increased with increasing evacuation temperature and reached 44.2percent at 573 K by the decomposition of Yb(II, III) amides to Yb(II, III) imides.The fraction of Yb(III) species increased at an evacuation temperature > 600 K, owing to the decomposition of Yb imides to Yb nitride with concomitant formation of hydrogen.The Yb(II) imide species catalyses the isomerization of but-1-ene and the Michael reaction of cyclopent-2-enone with dimethylmalonate, while the Yb(III) nitride species catalyses the hydrogenation of ethene.
Catalytic C-C bond formation promoted by Mg-Al-O-t-Bu hydrotalcite
Choudary,Lakshmi Kantam,Kavita,Venkat Reddy,Figueras
, p. 9357 - 9364 (2000)
Mg-Al-O-t-Bu-hydrotalcite catalyst was found to be an efficient, environmentally attractive and selective solid base catalyst for 1,4 Michael addition. Mg-Al-O-t-Bu hydrotalcite is also effective for simple synthesis of α,β-unsaturated esters and nitriles by condensation of the corresponding activated carboxylic esters or nitriles with various aldehydes by Knoevenagel condensation. These reactions proceeded at room temperature at a greater rate in the presence of Mg-Al-O-t-Bu hydrotalcite than in the presence of any of the other catalysts examined. (C) 2000 Elsevier Science Ltd.
Bifunctional Ligand-Assisted Catalytic Ketone α-Alkenylation with Internal Alkynes: Controlled Synthesis of Enones and Mechanistic Studies
Mo, Fanyang,Lim, Hee Nam,Dong, Guangbin
supporting information, p. 15518 - 15527 (2015/12/26)
Here, we describe a detailed study of the rhodium(I)-catalyzed, bifunctional ligand-assisted ketone α-C-H alkenylation using internal alkynes. Through controlling the reaction conditions, conjugated enamines, α,β- or β,γ-unsaturated ketones, can be selectively accessed. Both aromatic and aliphatic alkynes can be employed as coupling partners. The reaction conditions also tolerate a broad range of functional groups, including carboxylic esters, malonates, secondary amides, thioethers, and free alcohols. In addition, excellent E-selectivity was observed for the tetra-substituted alkene when forming the α,β-unsaturated ketone products. The mechanism of this transformation was explored through control experiments, kinetic monitoring, synthesizing the rhodium-hydride intermediates and their reactions with alkynes, deuterium-labeling experiments, and identification of the resting states of the catalyst.
An efficient organocatalytic method for highly enantioselective michael addition of malonates to enones catalyzed by readily accessible primary amine-thiourea
Dudzinski, Krzysztof,Pakulska, Anna M.,Kwiatkowski, Piotr
supporting information; experimental part, p. 4222 - 4225 (2012/09/22)
A practical and highly enantioselective Michael addition of malonates to enones catalyzed by simple and readily available bifunctional primary amine-thiourea derived from 1,2-diaminocyclohexane is reported. The addition of weak acids and elevated temperature (ca. 50 °C) improved the efficiency of the Michael reaction. This approach enables the efficient synthesis of 1,5-ketoesters with good yields, excellent enantioselectivities (up to 99% ee), and low loading (0.5-5 mol %) of simple chiral primary amine-thiourea catalysts, and is applicable in multigram scale synthesis.
