Asymmetric epoxidation of trans-methylstyrene with t-BuOOH/CHP and 66-68.

Asymmetric epoxidation of trans-methylstyrene with t-BuOOH/CHP and 66-68.

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The paper presents a comprehensive survey on the synthetic procedures of transition metal complexes of α-pyridinyl alcoholato, α-bipyridinyl alcoholato, α,α’-pyridinyl dialcoholato and α,α’-bipyridinyl dialcoholato ligands and their coordination chemistry. Greater emphasis is, however, given to the catalytic activity of the complexes in homogeneous...

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Context 1
... catalytic epoxidation of trans-methylstyrene with t-BuOOH or cumolhydroperoxide (CHP) in 1.0 mol% of catalysts 66-68 after 6 h at 50 or 70 °C was investigated. The results are shown in Table 2. 1 Both conv. and ee are in %. ...
Context 2
... reactions were run for four days to ensure complete conversion for the less reactive systems. The results of the reaction are presented in Table 12. The absolute configuration of the product depended on the absolute configuration at the benzylic centre rather than on the configuration of the pyrrolidine ring. ...

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... As part of a program that is concerned with the design and synthesis of novel Grubbs-type pre-catalysts, containing the hemilabile pyridinyl alcholato ligand for the metathesis of 1-alkene derivates, these ligands convey increased thermal stability of the pre-catalysts and decreased the extent of side reactions. [1][2][3][4][5][6][7] Incorporation of an alicyclic moiety in the hemilable ligands may further improve the thermal stability of these Grubbs-type pre-catalysts. 8 Filipescu 9 and Kusher 10 were able to synthesize the Diels-Alder adduct (2) from the cyclo-addition of cyclopentadiene and 1,4-naphthoquinone (1) by intramolecular photocyclization to produce the expected hexacyclo [7.4.2.0 1,9 .0 ...
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... 2,11 .0 4,9 .0 13,20 .0 ...
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A systematized survey of reviews and monographs published in 2018 on all aspects of heterocyclic chemistry is given.
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Background: The preparation and use of pyridinyl alcohols as ligands showed incredible increment in the past three decades. Important property of pyridinyl alcoholato ligands is their strong basicity, which is mainly due to the lack of resonance stabilization of the corresponding anion. This strongly basic anionic nature gives them high ability to make bridges between metal centers rather than to bind to only one metal center in a terminal fashion. They are needed as ligands due to their ability to interact with transition metals both covalently (with oxygen) and hemilabile coordination (through nitrogen). Objective: The review focuses on the wide application of α-pyridinyl alcohols, α,α'-pyridine diols, α- bipyridinyl alcohols, and α,α'-bipyridine diols as structure motifs in the preparation of important organic molecules which is due to their strongly basic anionic nature. Conclusion: It is clear from the review that in addition to their synthetic utility in the homogeneous and asymmetric catalytic reactions, the preparation of the crown ethers, cyclic and acyclic ethers, coordinated borates (boronic esters), pyridinyl-phosphine ligands, pyridinyl-phosphite ligands, and pyridinyl-phosphinite ligands is the other broad area of application of pyridinyl alcohols. In addition to the aforementioned applications they are used for modeling mode of action of enzymes and some therapeutic agents. Their strongly basic anionic nature gives them high ability to make bridges between metal centers rather than to bind to only one metal center in a terminal fashion in the synthesis of transition metal cluster complexes. Not least numbers of single molecule magnets that can be used as storage of high density information were the result of transition metal complexes of pyridinyl alcoholato ligands.