A New Coupled Catalytic System for Dihydroxylation of Olefins by H<sub>2</sub>O<sub>2</sub>

Bergstad, Katarina; Jonsson, Sandra Y.; Bäckvall, Jan‐E.

doi:10.1021/ja991710b

Cited by 105 publications

(44 citation statements)

References 21 publications

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“…Reactivo 4 (%) 9 (%) 10 (%) 3 (%) Bajo las condiciones experimentales descritas en el procedimiento Upjohn (Bergstad et al, 1999;VanRheenen et al, 1976) se consiguió obtener el mejor rendimiento en la preparación del diol 4, imprescindible para continuar con la síntesis enantioselectiva de (1).…”

Section: Entradaunclassified

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Aproximación a la síntesis enantioselectiva de achillifolina.

Rosales¹,

Bascón²,

Alcalá³

et al. 2017

REMCB

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RESUMEN.-En este artículo se presenta una aproximación biomimética a la síntesis enantioselectiva de achillifolina, una lactona sesquiterpénica natural aislada de Achillea millefolium subsp. Millenium. La ciclación carbocatiónica de epoxi-costunolida es la etapa clave de la secuencia sintética. Esta ciclación transanular permite la formación del esqueleto de 1,4-epoxi-ciclodecano presente en (+)-achillifolina.PALABRAS CLAVES: Achillifolina, carbocatión, ciclación, síntesis, terpenos ABSTRACT.-In this paper, an approximation biomimetic synthesis of achillifoline, a natural sesquiterpene lactone isolated from Achillea millefolium subsp. Millenium, is presented. Carbocationic cyclization of epoxycostunolide is the key step of the synthetic sequence. This transannular cyclization, allows the formation of the skeleton of 1,4-epoxy-cyclodecane presents in achillifoline.

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Section: Entradaunclassified

“…La formación del diol 4 y del cetol 9 se justifica mediante el mecanismo generalmente aceptado para las reacciones de oxidación de alquenos con KMnO 4 (Wolfe, et al, 1981) y OsO 4 (Bergstad et al, 1999;VanRheenen et al, 1976). La determinación estructural del diol 4 y del cetol 9 se realizó mediante técnicas espectroscópicas.…”

Section: Entradaunclassified

Aproximación a la síntesis enantioselectiva de achillifolina.

Rosales¹,

Bascón²,

Alcalá³

et al. 2017

REMCB

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“…The solvents were purified and dried using standard procedures [46]. Compounds 1a [17], 2a [42], 2b [18], 1a-H 2 [37,38], 1a-OCH 3 [47], and 2a-OH [47] were prepared according to previously described procedures. The NMR spectra of 1a, 2a, 2b, 1a-H 2 and 1a-OCH 3 are in accord with those reported in the literature.…”

Section: Synthesis and Characterization Of The Catalystsmentioning

confidence: 99%

“…Research into catalysis with flavinium salts was initiated by the investigation of the mode of action of flavin-4a-hydroperoxides, which were recognized as oxidizing agents in flavoenzymes [30][31][32][33][34][35][36]. So far, flavinium salts have been found to catalyze sulfoxidations [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], N-oxidations [24,37,38], and Baeyer-Villiger oxidations [39][40][41] in the similar way as flavindependent monooxygenases [13,14,[30][31][32][33][34][35][36]. Biomimetic systems utilizing a flavinium salt and oxygen as terminal oxidant have also been designed [42][43][44].…”

Section: Introductionmentioning

confidence: 99%

Insight into the catalytic activity of alloxazinium and isoalloxazinium salts in the oxidations of sulfides and amines with hydrogen peroxide

Ménová

Cibulka

2012

Journal of Molecular Catalysis A: Chemical

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“…As with the parent achiral osmium oxidation, NMMO can also be used as the oxidant (see above) [92]. However, rather than using NMMO in stoichiometric amounts, this morpholine component can be used in catalytic amounts by the addition of the biomimetic flavin 4 to set up a triple catalytic system where hydrogen peroxide is the oxidant [93][94][95]. Methyltrioxorhenium can be used in place of the flavin mimic [96], as can tungsten(VI) [97] and carbon dioxide [98].…”

Section: Bisalkaloid Ligandsmentioning

confidence: 99%

Cinchona Alkaloids as Chiral Ligands in Asymmetric Oxidations

Ager¹

2009

Cinchona Alkaloids in Synthesis and Catalysis

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For oxidation reactions, the cinchona alkaloids have been mainly employed to control the osmium-catalyzed conversion of an alkene to give a 1,2-diol or vicinal functionalized alcohol. As these are important asymmetric reactions, they have been the subject of a number of reviews [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. This chapter discusses the uses of these alkaloids as chiral ligands in asymmetric oxidation reactions. Oxidation reactions where an alkaloid is used in a phase-transfer sense are discussed in Chapter 5.The use of osmium tetroxide for the conversion of an alkene to a 1,2-diol is a wellestablished reaction [19][20][21][22]. The formation of an intermediate cyclic ester accounts for the cis-stereochemistry [21, 23-32] as reaction occurs on the least hindered face of the alkene [21,30,[33][34][35][36][37][38]. This steric effect is amplified in cyclic substrates [39,40]. The reaction conditions have to be carefully controlled to avoid oxidative cleavage of the diol product [28].There is a marked rate acceleration in the presence of a tertiary amine or pyridine [19,41]. This finding provided the background for the asymmetric dihydroxylation (AD) and, later, the asymmetric aminohydroxylation (AA) reactions as it is this ligand acceleration effect (LAE) that ensures the reaction pathway involving the ligand.The use of a cooxidant can reduce the amount of osmium required for a complete reaction of an alkene from stoichiometric to catalytic; some examples of oxidants that can achieve this are peroxides [20,22,35,37,[42][43][44] including hydrogen peroxide [20,42], chlorates [45], periodate [46,47], hypochlorite [48], N-methylmorpholine-N-oxide (NMMO) [22,34,35,37,49], potassium ferricyanide [50,51], and even air [52,53].Stereoselection for the OsO 4 reactions itself can also be observed when a directing group is adjacent to the alkene, such as in an allyl alcohol. An empirical rule has been devised, where the reagent approaches from the face opposite to the preexisting oxygen functionality. Although the hydroxy group may be protected, the presence of an acyl group reduces stereoselectivity. cis-Alkenes afford better selectivity

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A New Coupled Catalytic System for Dihydroxylation of Olefins by H₂O₂

Cited by 105 publications

References 21 publications

Aproximación a la síntesis enantioselectiva de achillifolina.

Aproximación a la síntesis enantioselectiva de achillifolina.

Insight into the catalytic activity of alloxazinium and isoalloxazinium salts in the oxidations of sulfides and amines with hydrogen peroxide

Cinchona Alkaloids as Chiral Ligands in Asymmetric Oxidations

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A New Coupled Catalytic System for Dihydroxylation of Olefins by H2O2

Cited by 105 publications

References 21 publications

Aproximación a la síntesis enantioselectiva de achillifolina.

Aproximación a la síntesis enantioselectiva de achillifolina.

Insight into the catalytic activity of alloxazinium and isoalloxazinium salts in the oxidations of sulfides and amines with hydrogen peroxide

Cinchona Alkaloids as Chiral Ligands in Asymmetric Oxidations

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A New Coupled Catalytic System for Dihydroxylation of Olefins by H₂O₂