1-Chloroalkyl p-tolyl sulfoxides as useful agents for homologation of carbonyl compounds: conversion of carbonyl compounds to .alpha.-hydroxy acids, esters, and amides and .alpha.,.alpha.'-dihydroxy ketones

Satoh, Tsuyoshi; Onda, Kenichi; Yamakawa, Kōji

doi:10.1021/jo00013a011

Cited by 26 publications

(9 citation statements)

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“…five-step synthetic approach to aromatic and aliphatic dihydroxy ketones starting from 1,4-dioxene and lithiation with tert-butyllithium, [4] a strategy including a ruthenium-catalyzed oxidation of allenes, [5] a double hydroxylation of silyl enol ethers with m-chloroperbenzoic acid, [6] the utilisation of 1-chloroalkyl p-tolyl sulfoxides as hydroxycarbonyl anion equivalents, [7] the approach by Enders et al to enantiomeric α,αЈ-dihydroxy ketones using dihydroxyacetone and chiral auxiliaries, [8] and an organoiron-templated route to cyclic species. [9] The lack of concise, direct strategies, presumably stems from the difficulties associated with creating a stable hydroxycarbonyl anion equivalent: umpolung approaches using dithianes or tert-butyl hydrazones can result in β-elimination of hydroxide or alkoxide upon generation of the hydroxycarbonyl anion.…”

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confidence: 99%

The First Mimetic of the Transketolase Reaction

et al. 2006

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Although the biocatalytic formation of acyclic α,α′‐dihydroxy ketones by transketolase is well documented in the literature, there is currently no one‐pot chemical synthesis of these dihydroxy ketones available. Here, we report preliminary results of an atom‐efficient one‐pot synthesis of α,α′‐dihydroxy ketones in water by a mimic of the transketolase reaction. The formation of a quaternary ammonium enolate is postulated in this tertiary‐amine‐mediated carbon–carbon bond‐forming reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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confidence: 99%

The First Mimetic of the Transketolase Reaction

et al. 2006

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“…When the reaction time was limited to 3 h, the yield for 47 was improved to 71 %. Elimination and asymmetric dihydroxylation of 41 (433 mg, 1.0 mmol) according to the standard protocol afforded the title compound 50 [49] (152 mg, 0.7 mmol, 70 %) after column chromatography (petroleum ether/ethyl acetate 10:1 Elimination and asymmetric dihydroxylation of 66 (410 mg, 1.0 mmol) according to the standard protocol afforded the title compound 61 a,b [51] (151 mg, 0.78 mmol, 78 %) after column chromatography (petroleum ether/ ethyl acetate 10:1). The diastereomeric excess of 61 a,b* was determined by chiral GC: isothermal 122 8C, 27.42 min (2S, 3R) , 1 H, 2-H), 4.25 (dd, J 1.8, 4.8 Hz 1 H, 5'-H), 3.41, 3.37 (2s, 6 H, 2 OCH 3 ), 2.76 (br, 1 H, COH), 1.06, 1.40, 1.31, 1.30 Elimination and asymmetric dihydroxylation of 68 (536 mg, 1.0 mmol) by applying the standard protocol described above except that a threefold excess of the AD-mix a reagent was employed afforded the title compounds (2S)-69 a (257 mg, 0.81 mmol, 81 %) and 70 (18.1 mg, 0.06 mmol, 6 %) after column chromatography (petroleum ether/ethyl acetate 10:1).…”

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confidence: 99%

Asymmetric Nucleophilic Acylation of Aldehydes via 1,1-Heterodisubstituted Alkenes

Monenschein

Dräger

Jung

et al. 1999

Chemistry - A European Journal

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Aldehydes are asymmetrically acylated by a two step sequence that is initiated by a homologation step to 1,1-heterodisubstituted alkenes followed by asymmetric dihydroxylation. Thus, ketene O,S-acetals are efficiently prepared from aldehydes by a Peterson olefination with lithiated methoxy-phenylthiotrimethylsilyl methane 14 as the C-1 source. Although they are dihydroxylated with the Sharpless catalyst with moderate to good enantioselectivity (62 ± 80 % ee), the process is not efficient owing to the low chemical yields of the desired a-hydroxy methyl esters (7 ± 37 %). Use of the corresponding sulfoxide 24 or sulfon 25 led to an improved chemical yield of a-hydroxy methyl ester 19, but the stereoselectivity was diminished. In contrast, intermediate ketene O,O-acetals are prepared by a Horner ± Wittig reaction with phosphine oxide 31 and are dihydroxylated both with good chemical and stereochemical yield. The concept is applicable to aromatic, aliphatic, and chiral aldehydes. For example, this short sequence allows exclusive and independent preparation of both diastereomeric heptoses 69 a and 69 b.

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“…1,4-Dioxene was lithiated with tert-butyllithium then reacted with the relevant aldehyde or ketone and treatment with MCPBA, then sodium borohydride and hydrolysis with acidic silca gel gave the racemic dihydroxy ketone (Scheme (2)) [8]. Alternatively, 1-chloroalkyl p-tolyl sulfoxides have been reported as hydroxymethylcarbonyl anion equivalents [9]. The chloroalkyl aryl sulfoxides are prepared in two steps from arene thiols and alkyl halides, then treated with lithium diisopropylamine (LDA) and the aldehyde or ketone.…”

Section: Chemical Synthesis Of '-Dihydroxy Ketonesmentioning

confidence: 99%

“…The chloroalkyl aryl sulfoxides are prepared in two steps from arene thiols and alkyl halides, then treated with lithium diisopropylamine (LDA) and the aldehyde or ketone. Subsequent refluxing in xylene and oxidation with osmium tetroxide gave the desired , '-dihydroxy ketones in good yields [9].…”

Section: Chemical Synthesis Of '-Dihydroxy Ketonesmentioning

confidence: 99%

“…A study was carried out using racemic 1,3-dihydroxy-1-phenylpropan-2-one (8) which was converted to 2-amino-1-phenylpropane-1,3-diol (9) using C. violaceum -TAm and also a chemical reductive amination using benzylamine and then removal of the benzylic group using H 2 and Pd/C. The products were triacetylated for HPLC analysis, together with (1S,2S)-and (1R,2R)- (9), which are commercially available. In addition (1R,2S)-(9) was synthesised via a four-step procedure in 70% de which was also triacetylated.…”

Section: Stereoselectivity Of C Violaceum -Tammentioning

confidence: 99%

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α, α -Dihydroxy Ketones and 2-Amino-1,3-diols: Synthetic and Process Strategies Using Biocatalysts

Hailes¹,

Dalby²,

Lye³

et al. 2010

COC

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There is increasing interest in the use of biocatalysts in synthetic applications due to their ability to achieve highly stereoselective and atom efficient conversions. Recent developments in molecular biology techniques and synthetic biology have also enhanced potential applications using non-natural substrates. Here we review strategies to , '-dihydroxy ketones and 2-amino-1,3-diols via the use of transketolase, a carbon-carbon bond forming biocatalyst, and the enzyme transaminase which converts aldehydes and ketones to amines. Using an integrated strategy we have investigated new chemistries and assays, identified novel biocatalysts and used directed evolution strategies, together with miniaturization studies and modelling to achieve rapid and predictive process scale-up.The use of biocatalysts for the synthesis of biologically active compounds is of increasing interest to the chemical, pharmaceutical and biotechnology sectors in the search for sustainable, cost effective, synthetic strategies. In addition, developments in molecular biology tools and protein and pathway engineering, leading to improved biocatalyst substrate tolerance, specific activities and processing properties are resulting in extensive possibilities for the use of enzymes in synthesis. Current interest in synthetic biology approaches and also cascade reactions, with applications in biofuel synthesis as well as routes to pharmaceuticals, will result in exciting developments and opportunities using biocatalysts in the next decade. At UCL, a multidisciplinary approach has been established in the Departments of Chemistry, Biochemical Engineering and Structural and Molecular Biology (BiCE programme) focusing initially on biocatalytic approaches to , '-dihydroxy ketones and 2-amino-1,3-diols [1]. This has led to the development of new biocatalysts and chemistries and new miniaturization tools for rapid and predictable process scale-up. This review will focus on the use of two enzymes, transketolase (TK) (EC 2.2.1.1) and transaminase (TAm) for the synthesis of the important structural motifs , '-dihydroxy ketones and 2-amino-1,3-diols and biocatalyst scale-up tools.

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1-Chloroalkyl p-tolyl sulfoxides as useful agents for homologation of carbonyl compounds: conversion of carbonyl compounds to .alpha.-hydroxy acids, esters, and amides and .alpha.,.alpha.'-dihydroxy ketones

Cited by 26 publications

References 0 publications

The First Mimetic of the Transketolase Reaction

The First Mimetic of the Transketolase Reaction

Asymmetric Nucleophilic Acylation of Aldehydes via 1,1-Heterodisubstituted Alkenes

α, α -Dihydroxy Ketones and 2-Amino-1,3-diols: Synthetic and Process Strategies Using Biocatalysts

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1-Chloroalkyl p-tolyl sulfoxides as useful agents for homologation of carbonyl compounds: conversion of carbonyl compounds to .alpha.-hydroxy acids, esters, and amides and .alpha.,.alpha.'-dihydroxy ketones

Cited by 26 publications

References 0 publications

The First Mimetic of the Transketolase Reaction

The First Mimetic of the Transketolase Reaction

Asymmetric Nucleophilic Acylation of Aldehydes via 1,1-Heterodisubstituted Alkenes

&#945;, &#945; -Dihydroxy Ketones and 2-Amino-1,3-diols: Synthetic and Process Strategies Using Biocatalysts

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α, α -Dihydroxy Ketones and 2-Amino-1,3-diols: Synthetic and Process Strategies Using Biocatalysts