Author
Kazushige Maruyama
Bio: Kazushige Maruyama is an academic researcher from Osaka Institute of Technology. The author has contributed to research in topics: Schiff base & Cobalt. The author has an hindex of 12, co-authored 32 publications receiving 375 citations.
Papers
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TL;DR: The asymmetric induction of styrene catalyzed by optically active cobalt Schiff base complexes in 2-propanol gives an enantiomer excess of 1-phenyl-ethanol as discussed by the authors.
51 citations
TL;DR: In this paper, the authors showed that the catalytic activity of Co(SB) depended on the nature of the SB ligand: the formal potential E° and steric factors seem to affect the reaction rate.
Abstract: Cobalt Schiff base complexes [Co(SB)] catalyze the oxidation of anilines (1) with tert-butyl hydroperoxide to give nitrobenzenes 2 and 4-(tert-butylperoxy)-2,5-cyclohexadien-1-imine derivatives 3 in yield distributions depending on the substitution mode of the substrate. 4-Alkyl- and 4-aryl-2,6-di-tert-butylanilines gave mixtures of 2 and 3, where the higher the bulkiness of the 4-substituent, the higher the yield of 2. With 2,4,6-trimethylaniline, the ratio of oxidations of the nitrogen and C-4 atoms was almost the same; but a hydrolyzed product 5 of the imine was obtained. 2,4,6-Triphenylaniline gave only 2. Nitrobenzene derivatives were also obtained from 2,6-dialkylanilines and 4-substituted anilines. The catalytic activity of Co(SB) depended on the nature of the SB ligand: the formal potential E° and steric factors seem to affect the reaction rate. Kinetic studies showed that the key step may involve hydrogen abstraction from the aniline, presumably by t-BuO• generated from homolytic decomposition o...
48 citations
30 citations
Journal Article•
TL;DR: Co III (salpr), a six coordinate cobalt base complex, promotes the highly selective conversion of 1-(o-hydroxyaryl)-1,3-diketones to 4H-chromen-4-ones under neutral conditions as discussed by the authors.
Abstract: Co III (salpr)(OH), a six coordinate cobalt Schiff base complex, promotes the highly selective conversion of 1-(o-hydroxyaryl)-1,3-diketones to 4H-chromen-4-ones under neutral conditions
27 citations
TL;DR: In this paper, it was shown that base catalysis by Co(salpr) (OH) produced in situ is responsible for the reaction, which is found to proceed reversibly.
26 citations
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1,516 citations
TL;DR: The first salen ligand and Cu complex were discovered in 1889, and gradually the potential catalytic activity of subsequent salen species has been recognised, particularly in the case of achiral salen complexes in oxidation reactions.
Abstract: The first salen ligand and Cu complex were discovered in 1889, and gradually the potential catalytic activity of subsequent salen species has been recognised, particularly in the case of achiral salen complexes in oxidation reactions. The development of chiral salen metal complexes and catalysts in the last decade has however stimulated a very rapid growth in the chemistry and application of these species. The variety of asymmetric reactions in which particular chiral metal salen complexes are proving useful grows steadily, and there is no evidence of this growth slowing. This review summarises the key work and references on soluble chiral metal salen complex catalysts categorised according to the metal centre. It also describes the work to date on producing supported heterogeneous chiral analogues of some of these.
856 citations
TL;DR: This review compiles examples of the most promising applied Schiff bases and their complexes in different areas and explains how to understand the properties of both ligands and metal can lead to the synthesis of highly active compounds.
420 citations
392 citations
TL;DR: In this article, the authors focused on three new approaches, namely, the cross-coupling of alcohols with amines, the self coupling of primary amines and the oxidative dehydrogenation of secondary amines.
Abstract: Imines as valuable intermediates are widely applied in pharmaceutical syntheses and organic transformation. However, the traditional imine synthesis involves unstable aldehydes, dehydrating agents, and Lewis acid catalysts. The topic of this review is focused on three new approaches, namely, the cross-coupling of alcohols with amines, the self-coupling of primary amines, and the oxidative dehydrogenation of secondary amines, utilizing much more readily available starting materials and green oxidant (O2/air) to furnish the imine products. The related catalysts are classified into metal, metal-free, photo-, and bioinspired catalysts. Particular emphasis is placed on the high-activity, low-cost, and versatile catalysts; key factors that affect the catalytic activity and reaction mechanisms are also highlighted.
378 citations