Chemical and Electrochemical Asymmetric Dihydroxylation of Olefins in I2−K2CO3−K2OsO2(OH)4 and I2−K3PO4/K2HPO4−K2OsO2(OH)4 Systems with Sharpless' Ligand

Torii, Sigeru; Liu, Ping; Bhuvaneswari, N. Sudha; Amatore, Christian; Jutand, Anny

doi:10.1021/jo952137r

Cited by 96 publications

(34 citation statements)

References 32 publications

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“…[1][2][3] For this reason, considerable and continuous efforts have been made to improve the optical purity of the resulting diols with the desired absolute configuration. 2,3 Similarly, the enantioselectivity estimation of a increasing number of chiral catalysts demands convenient, fast and sensitive methods to measure enantiomeric excesses and impurities of the chiral vicinal diol products. Besides the major HPLC method, cyclodextrin-modified capillary zone electrophoresis (CZE) is enjoying increasing popularity.…”

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Chiral Separation of Synthetic Vicinal Diol Compounds by Capillary Zone Electrophoresis with Borate Buffer and b-Cyclodextrin as Buffer Additive

et al. 2006

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The osmium-catalyzed asymmetric dihydroxylation (AD) of olefins is one of the most widely used methods for the synthesis of chiral vicinal diols, which are the synthetic intermediates of chiral drugs, natural products and fine chemicals. [1][2][3] For this reason, considerable and continuous efforts have been made to improve the optical purity of the resulting diols with the desired absolute configuration. 2,3 Similarly, the enantioselectivity estimation of a increasing number of chiral catalysts demands convenient, fast and sensitive methods to measure enantiomeric excesses and impurities of the chiral vicinal diol products. Besides the major HPLC method, cyclodextrin-modified capillary zone electrophoresis (CZE) is enjoying increasing popularity. 4,5 In contrast to HPLC, in which chiral selectors are immobilized to the solid support, CZE shows many advantages by dissolving chiral selector in separation buffer, such as simplification, high efficiency, reduced analysis time, and smaller sample volumes. In CZE, borate buffers were widely used for the separation of carbohydrates, glycoproteins, nucleosides, and other compounds of biological interest. [6][7][8][9][10][11][12][13] The phenomenon of borate complexation has been extensively studied and the principle of mixed borate-cyclodextrin complexation has been found to be a useful approach for the chiral separation of neutral compounds with diol structures. [6][7][8][9] For neutral analytes in the CZE separation mode, enantioseparation is not achievable with neutral CDs unless the electrophoretic system is modified with the use of a buffer system containing CD which can form charged complexes with analytes or with the addition of charged CDs in a buffer system. In those studies, to the best of our knowledge, so far only two articles on the enantioseparation of vicinal diols by the neutral cyclodextrin-modified capillary electrophoresis have been reported. 14,15 Moreover, the enantioseparation of hydrobenzoin, which is a 1,2-diol compound, and structurally related benzoin compounds have been achieved using charged CDs alone or mixed with neutral CDs as chiral selectors. 16,17 Unfortunately, no detailed information on the enantioseparation of typical vicinal diol compounds was provided. Thus, enantioseparation and migration behavior of typical vicinal diol compounds in the presence of borate complexation need to be explored further.In this study, the optimum conditions for the separation of six 1,2-diols synthesized in our laboratory according to literature methods 18,19 using native β-CD by CZE were described. Especially, the enantioseparation and migration behavior of several 1,2-diols, such as 1-(3-chlorophenyl)-1,2-ethanediol, 1-methyl-1-phenyl-1,2-ethanediol, 2-methyl-1-phenyl-1,2-ethanediol and 1-naphthyl-1,2-ethanediol, were firstly explored with neutral β-CD as a chiral selector in a borate buffer at an alkaline pH. For our studies, the influences of the concentration of β-CD, the pH of borate buffer and the buffer concentration on the chiral separation we...

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Chiral Separation of Synthetic Vicinal Diol Compounds by Capillary Zone Electrophoresis with Borate Buffer and b-Cyclodextrin as Buffer Additive

et al. 2006

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“…It only requires [% in weight] catalytic amounts of (i) the pre-oxidant: potassium osmate dihydrate [0.104%] and of (ii) the chiral inductor derived from Cinchona alkaloid: often (DHQD) 2 PHAL or (DHQ) 2 PHAL [0.552%] to produce diols in extremely good yields and enantiomeric excesses. A series of selected ligands, all belonging to the Cinchona alkaloid family but attached to different linkers, are available for borderline cases [1a].In fact, two premixes are commercially available under the name of AD-mix [2]. Although the amount of active ingredients is negligible, the amount of reagent required is important (1.4 g of AD-mix per mmole of olefin), mainly due to the excess of cooxidant {potassium ferricyanide, K 3 Fe(CN) 6 [69.96%]} and of base [potassium carbonate, K 2 CO 3 (29.39%)].…”

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“…In fact, two premixes are commercially available under the name of AD-mix [2]. Although the amount of active ingredients is negligible, the amount of reagent required is important (1.4 g of AD-mix per mmole of olefin), mainly due to the excess of cooxidant {potassium ferricyanide, K 3 Fe(CN) 6 [69.96%]} and of base [potassium carbonate, K 2 CO 3 (29.39%)].…”

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“…Several oxidants, such as N-methyl morpholine N-oxide (NMO) [1a], sodium peroxodisulphate (Na 2 S 2 O 8 ) [1a], and iodine (I 2 ) [2], which have been used in place of the ferricyanide, proved to be much less efficient or less practicable. This is the case of NMO [3], which constantly allows the high yield synthesis of diols from olefins but which did not provide the high ee's obtained with potassium ferricyanide.…”

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“…allylphenylselenides are reacted in place of benzyl phenyl selenide with AD-mix (Scheme 4, entry a) 2) olefins are present in the medium besides catalytic amount of potassium osmate dihydrate and stoichiometric quantities of benzyl phenyl selenoxide (Scheme 4, entry b).…”

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Asymmetric dihydroxylation of C,C double bonds using catalytic amounts of osmium tetroxide, selenides, and air

Krief

Colaux-Castillo²

2002

Pure and Applied Chemistry

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Selenides, selenoxides, osmium tetroxide, and potassium osmate dihydrate are in equilibrium in aqueous tert-butanol containing potassium carbonate. We took advantage of this feature to withdraw the equilibrium in each of the two directions to produce allylalcohols from allylselenides and diols from olefins. The latter reaction performed in the presence of catalytic amounts of Cinchona alkaloids and osmium tetroxide allows the enantioselective dihydroxylation of C,C double bonds.

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Sauerstoff und Osmium – ein neues Paar für Dihydroxylierungen?

Wirth¹

2000

Angewandte Chemie

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Chemical and Electrochemical Asymmetric Dihydroxylation of Olefins in I₂−K₂CO₃−K₂OsO₂(OH)₄ and I₂−K₃PO₄/K₂HPO₄−K₂OsO₂(OH)₄ Systems with Sharpless' Ligand

Cited by 96 publications

References 32 publications

Chiral Separation of Synthetic Vicinal Diol Compounds by Capillary Zone Electrophoresis with Borate Buffer and b-Cyclodextrin as Buffer Additive

Chiral Separation of Synthetic Vicinal Diol Compounds by Capillary Zone Electrophoresis with Borate Buffer and b-Cyclodextrin as Buffer Additive

Asymmetric dihydroxylation of C,C double bonds using catalytic amounts of osmium tetroxide, selenides, and air

Sauerstoff und Osmium – ein neues Paar für Dihydroxylierungen?

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