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Variation of the electronic nature of the tetraphenyl-cyclopentadienone ligand in organoruthenium complexes influences their utility for racemisation of model chiral amines. Our study highlights the need to balance reactivity and selectivity in the design of racemisation catalysts. Electron-poor Shvo-type catalysts are, at first sight, more effective for racemisation, but yield more by-product; electron-rich complexes are less proficient at racemisation, but lead to less by-product. [ABSTRACT FROM AUTHOR]

(S,S)- or (R,R)-Naph-diPIM-dioxo-i-Pr-CpRu(II) complex with a Brønsted acid catalyzes dehydrative intermolecular C-allylation with high enantio- and regioselectivity. The new soft Ru/hard H+ combined catalyst can also be used for intramolecular C-, N-, and O-allylations, giving nearly enantiomerically pure α-alkenyl-substituted cyclic compounds. As water is only the co-product, the synthetic process can be readily scaled up. [ABSTRACT FROM AUTHOR]

A catalytic tandem olefin migration-aldol condensation process with allylic carbinols and aryl aldehydes was performed with 0.5 mol% of an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin supported phosphine-ruthenium complex in water as a single reaction medium under heterogeneous conditions to give the corresponding aldols with syn selectivity. Inverse stereoselectivity (anti selectivity) was observed when the reaction was carried out in the presence of K2CO3. [ABSTRACT FROM AUTHOR]

Ruthenium-porphyrins are effective catalysts for a wide variety of carbenoid transfer reactions, such as alkene cyclopropanation, carbon-hydrogen, nitrogen-hydrogen, or sulfur-hydrogen (X-H, X = C, N, S) bond insertion, diazo coupling, carbonyl or azomethine ylide formation/1,3-dipolar cycloaddition, and halonium, sulfonium, or ammonium ylide formation/[2,3]-sigmatropic rearrangement reactions. Extensive studies have demonstrated that ruthenium-porphyrins exhibit high stability, high product turnover numbers, and remarkable selectivity in catalytic carbenoid transfer reactions. The catalysis has been successfully applied to the synthesis of organic building blocks and natural products, and to the modification of peptides and proteins. 1 Introduction 2 Catalyst Types 3 Cyclopropanation Reactions 4 Carbon-Hydrogen, Nitrogen-Hydrogen, and Sulfur-?Hydrogen Bond Insertion Reactions 5 Alkene Formation Reactions 5.1 Coupling of Diazo Compounds 5.2 Olefination of Aldehydes 6 Ylide Formation and Subsequent Reactions 6.1 Carbonyl Ylide Formation/1,3-Dipolar Cycloaddition 6.2 Azomethine Ylide Formation/1,3-Dipolar Cycloaddition 6.3 Halonium Ylide Formation/[2,3]-Sigmatropic Rearrangement 6.4 Sulfonium or Ammonium Ylide Formation/[2,3]-Sigmatropic Rearrangement 7 Comparison of (Carbene)ruthenium-Porphyrin Complexes with Iron and Osmium Analogues 8 Conclusion [ABSTRACT FROM AUTHOR]

Second-generation Grubbs' catalyst and Hoveyda-Grubbs' catalyst are able to catalyze both crossed [2+2+2] cyclotrimerization of diynes with alkynes and di- or trimerizations of diynes. Selection of the reaction conditions allows us to favor one particular process. The process is selective when applied to unsymmetric diynes. [ABSTRACT FROM AUTHOR]

A binary catalyst system of [RuCl 2(? 6-arene)] 2and a protic aminothiol (SN) ligand has been found to promote hydrogen transfer between alcohols and carbonyl compounds. The chiral catalyst system with the pipecolinol-derived chiral SN ligand displays excellent stereoselectivity in the asymmetric transfer hydrogenation of aromatic ketones using HCO 2H-Et 3N. Novel unsymmetrical bis(thiolate)-bridged binuclear complex, which is relevant to the generation of catalytically active species, has been synthesized and structurally characterized. [ABSTRACT FROM AUTHOR]

The article presents a research study concerning the effectiveness of C-H bond activation for the catalysis of Ruthenium (II) and cyclic amines' alkylation. Study shows the popularity of such activation in the field of organic chemistry and cites its efficacy in converting cyclic amines based on the findings of Christian Bruneau. The role of hydrogen-transfer and oxidation is also cited.