First controlled asymmetric dihydroxylation of thiophene acrylates

Bonini, Carlo; D’Auria, Maurizio; Fedeli, Pietro

doi:10.1016/s0040-4039(02)00688-3

Cited by 15 publications

(4 citation statements)

References 15 publications

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“…After purification (5% MeOH/DCM, R f = 0.15), compound 14m was afforded as a pale yellow oil (53 mg, 32% yield) as a 3:2 mixture of diastereomers. Characterization matches previous published results …”

Section: Methodssupporting

confidence: 62%

“…Characterization matches previous published results. 41 Methyl 2,3-Dihydroxy-3-(pyridin-2-yl)propanoate (14n). The general procedure was followed using DHF dihydrate (150 mg, 0.814 mmol), 2-pyridyl carboxyaldehyde 8n (261 mg, 2.44 mmol) in 0.15 mL of THF, NaOH (130 mg, 3.26 mmol), and LiOH•H 2 O (68 mg, 1.63 mmol) in deionized water.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Base-Mediated Cascade Aldol Addition and Fragmentation Reactions of Dihydroxyfumaric Acid and Aromatic Aldehydes: Controlling Chemodivergence via Choice of Base, Solvent, and Substituents

2018

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The diester derivative of dihydroxyfumaric acid (DHF) has been used exclusively as an electrophile in organic synthesis. However, the synthetic utility of DHF's nucleophilic reactivity, contained in the ene-diol moiety, has been underexplored. Inspired by recently observed pH-dependent chemodivergent nucleophilic aldol reactions of dihydroxyfumarate (DHF) with glyoxylate and formaldehyde, we report herein the control and synthetic application of base-controlled chemodivergent reactions between dihydroxyfumarate and aromatic and heteroaromatic aldehydes. With hydroxide as the base in a predominantly aqueous medium, aldol addition followed by deoxalation occurs to provide various 3-aryl-2,3-dihydroxypropanoic acids. With triethylamine as the base in THF, 1-aryl-2,3-dihydroxypropanones are the products of the reaction. In order to understand the difference in reactivity between DHF, its dicarboxylate, and its dimethyl ester, we undertook computational and experimental studies that provide a rationale as to why the dihydroxyfumarate (DHF) is a nucleophile while the corresponding diester reacts as an electrophile.

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Section: Methodssupporting

confidence: 62%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Base-Mediated Cascade Aldol Addition and Fragmentation Reactions of Dihydroxyfumaric Acid and Aromatic Aldehydes: Controlling Chemodivergence via Choice of Base, Solvent, and Substituents

2018

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“…Finally, the cyclic erythro diols (−)- 1n and (+)- 1o were prepared by AD of indene and 1,2-dihydronaphthalene, respectively, using (DHQ) 2 AQN ligand . Diols ( R )-(−)- 1a , ( R )-(−)- 1b , ( R )-(−)- 1c , ( R )-(−)- 1f , ( R )-(−)- 1i ,(2 S ,3 R )-(−)- 1j , (2 R ,3 R )-(+)- 1m , (1 S ,2 R )-(−)- 1n , and (1 S ,2 R )-(+)- 1o were of known AC. The AC of diols ( R )-(−)- 1d , ( R )-(−)- 1g , ,,20b ( R )-(−)- 1h , ( 1R,2R )-(−)- 1k , and ( 1R,2S )-(−)- 1l 32 were attributed only on the basis of empirical correlations.…”

Section: Resultsmentioning

confidence: 99%

A General and Nonempirical Approach to the Determination of the Absolute Configuration of 1-Aryl-1,2-diols

et al. 2004

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We describe herein a simple, general, and reliable nonempirical approach, based on the exciton coupling method, to assign the absolute configuration of the benzylic stereogenic center of 1-aryl-1,2-diols. According to this method, it is only necessary to prepare the 4-biphenylboronic esters of the diols and to record their CD spectra in the 230-300 nm range, i.e., in the range corresponding to the long-axis (1)L(a) transition of the biphenyl chromophore. From the sign of the CD couplet or Cotton effect at 260 nm it is possible to know the chirality defined by the aryl and biphenyl chromophore transitions and then to determine the absolute configuration of the benzylic carbon. By this approach, simple rules have been formulated which allow us to establish the absolute configuration of many classes of 1-aryl-1,2-diols.

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“…Although the furyl and thiophenyl derivatives of the ester 34 gave good regio-and enantioselectivities, the pyrrol analogues did not undergo reaction (Scheme 3.43) [367,368]. Although the furyl and thiophenyl derivatives of the ester 34 gave good regio-and enantioselectivities, the pyrrol analogues did not undergo reaction (Scheme 3.43) [367,368].…”

Section: Aminohydroxylation J57mentioning

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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First controlled asymmetric dihydroxylation of thiophene acrylates

Cited by 15 publications

References 15 publications

Base-Mediated Cascade Aldol Addition and Fragmentation Reactions of Dihydroxyfumaric Acid and Aromatic Aldehydes: Controlling Chemodivergence via Choice of Base, Solvent, and Substituents

Base-Mediated Cascade Aldol Addition and Fragmentation Reactions of Dihydroxyfumaric Acid and Aromatic Aldehydes: Controlling Chemodivergence via Choice of Base, Solvent, and Substituents

A General and Nonempirical Approach to the Determination of the Absolute Configuration of 1-Aryl-1,2-diols

Cinchona Alkaloids as Chiral Ligands in Asymmetric Oxidations

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