نتایج جستجو برای: rhodium
تعداد نتایج: 4139 فیلتر نتایج به سال:
Treatment of a-(5,6-dimethylbenzimidazolyl)hydrogenobamide with rhodium carbonyl chloride [Rh(C0)2C1]2 in ethyl alcohol-glacial acetic acid in the presence of sodium acetate produces chlororhodibalamin as the principal rhodium corrinoid. Chlororhodibalamin, when reacted with silver nitrate, is converted into aquorhodibalamin. In the absence of oxygen, chloroand aquorhodibalamin are readily redu...
Inspired by nature's ability to regulate catalysis using physiological stimuli, azobenzene was incorporated into Rh(bis)diphosphine CO2 hydrogenation catalysts to photoinitiate structural changes to modulate the resulting catalytic activity. The rhodium bound diphosphine ligands (P(Ph2)-CH2-N(R)-CH2-P(Ph2)) contain the terminal amine of a non-natural amino acid, with the R-group being either β-...
Rhodium on a La-containing ZrO2 support effectively eliminated NOx from a synthetic auto exhaust gas under fluctuating oxygen conditions. Rhodium particles maintained a low oxidation state on the ZrO2-La2O3 mixed oxide even after treatment with 5% O2 at 773 K, highlighting the significant effect of the La addition.
A highly enantioselective rhodium-catalysed conjugate addition of phenylboronic acid to cyclic enones has been achieved using a dynamic library of chiral phosphorus ligands; the tropos/atropos nature of the ligands in the rhodium complex has been characterised via 31P-NMR.
Chiral rhodium(I)-catalyzed highly enantioselective arylation of aliphatic N-sulfonyl aldimines with arylboronic acids has been developed. This transformation is achieved by the use of a rhodium/bis(phosphoramidite) catalyst to give enantiomerically enriched α-branched amines (up to 99 % ee). In addition, this system enables efficient synthesis of (+)-NPS R-568 and Cinacalcet which are calcimim...
The rhodium-catalyzed reactions of 3-diazoindolin-2-imines with N,N-dialkylanilines, N-allyl-N-alkylanilines, and N-propargyl-N-alkylanilines and 3-diazoindolin-2-imines furnished 3-aryl-2-aminoindoles, 3-allyl-3-amino-2-iminoindolines, and tetrahydro-[1,4]diazepino[2,3-b]indoles, respectively. 3-Diazoindolin-2-imines acted as precursors of α-imino rhodium carbenes in these transformations.
The rhodium(III)-catalyzed hydroarylation of internal alkynes is described. Good yields are obtained for a variety of alkynes, and excellent regioselectivity is observed for unsymmetrically substituted alkynes. The reaction also gives good yields for a range of arenes. Preliminary mechanistic investigations suggest that this reaction proceeds through arene metalation with the cationic rhodium c...
A novel rhodium-catalyzed linear codimerization of alkyl phenyl ketenes with internal alkynes to dienones and a novel synthesis of furans by an unusual cycloaddition of diaryl ketenes with internal alkynes have been developed. These reactions proceed smoothly with the same rhodium catalyst, RhCl(PPh(3))(3), and are highly dependent on the structure and reactivity of the starting ketenes.
The synthesis of rhodium(I) and iridium(I) complexes of chiral MOP-phosphonite ligands is reported. The full characterisation of η(1),η(6)-(σ-P, π-arene) chelated 18VE rhodium(I) complexes reveals hemilabile binding on the arene which has been quantitatively analysed.
1,3-Enynes containing allylic hydrogens cis to the alkyne function as three-carbon components in rhodium(III)-catalyzed, all-carbon [3+3] oxidative annulations to produce spirodialins. The proposed mechanism of these reactions involves the alkenyl-to-allyl 1,4-rhodium(III) migration.
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