Flow Synthesis of (3R)- and (3S)-(E)-1-Iodohexa-1,5-dien-3-ol: Chiral Building Blocks for Natural Product Synthesis

Katayama, Sota; Koge, Tomoyuki; Katsuragi, Satoko; Akai, Shuji; Oishi, Tohru

doi:10.1246/cl.180475

Cited by 12 publications

(5 citation statements)

References 28 publications

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“…First, we examined reactions in two types of reactors under different alkali concentrations and residence times. The flow reactors tested were a stainless used steel (SUS) pipe ( L = 5.0 m, inner diameter = 0.5 mm, and V = 5 mL) and Comet X (Table ). The hydrolysis reaction was performed with mixtures of a KOH solution at various concentrations and the MeOH extract of P. senega .…”

Section: Results and Discussionmentioning

confidence: 99%

Preparation of Tenuifolin from Polygala senega L. Root Using a Hydrolytic Continuous Flow System under High-Temperature, High-Pressure Conditions

et al. 2021

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An improved process for preparing tenuifolin (presenegenin 3-β-d-glucopyranoside) from the root of Polygala senega L. was developed. A crude saponin mixture extracted from P. senega was subjected to hydrolysis, and the reactivity of compounds in the extract was controlled by utilizing the combination of a flow reactor and experimental design. In addition, column chromatography with HP 20, a synthetic polystyrenic adsorbent, allowed the gram-scale preparation of tenuifolin in a continuous manner with fewer steps. This approach shortens the total time required for gram-scale preparation from 16 to 5 h in a continuous manner while improving the yield from 0.59% to 2.08% (w/w).

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Section: Results and Discussionmentioning

confidence: 99%

Preparation of Tenuifolin from Polygala senega L. Root Using a Hydrolytic Continuous Flow System under High-Temperature, High-Pressure Conditions

et al. 2021

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“…Removal of the acetyl groups of 5 (a mixture of diastereomers at C32 in a 5 : 1 ratio) was carried out under the flow conditions ( Figure 3). [20] A solution of 5 in methanol (0.5 M) was passed through anion exchange resin (MeO À form) packed in a column (ϕ5 × 100 mm) at a flow rate of 0.1 mL/min at room temperature to give tetraol 6 quantitatively after simple evaporation of the eluent. This procedure is useful for water soluble polar products such as 6, and can be easily scaled up by increasing the elution volume.…”

Section: Resultsmentioning

confidence: 99%

“…The A‐ring iodoolefins 3 a and 3 b were synthesized from the known compound 5 as shown Scheme . Removal of the acetyl groups of 5 (a mixture of diastereomers at C32 in a 5 : 1 ratio) was carried out under the flow conditions (Figure ) . A solution of 5 in methanol (0.5 M) was passed through anion exchange resin (MeO − form) packed in a column (φ5×100 mm) at a flow rate of 0.1 mL/min at room temperature to give tetraol 6 quantitatively after simple evaporation of the eluent.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Stereochemistry of the C30−C63 Section of Karlotoxin 2

Umeno

Oishi

2020

Asian J Org Chem

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Karlotoxin 2 (KmTx2) is a marine natural product isolated from the dinoflagellate Karlodinium veneficum. The absolute configuration of KmTx2 was determined by NMR analysis in combination with degradation of the natural product, and the absolute configuration at C49 was revised by computational analysis. On the other hand, we reported revision of the absolute configuration of amphidinol 3 (AM3), whose structure is similar to that of KmTx2, by comparing NMR data of the synthesized partial structures and total synthesis of AM3. In this paper, we report the synthesis of the partial structures of KmTx2 corresponding to the C30À C63 section, and the diastereomer at C37, C41À C43, and C45À C49, which is hypothetically proposed on the basis of the revised structure of AM3. Comparison of the NMR data of the synthetic specimens with those of the natural product suggested that the absolute configuration of KmTx2 is revised to be 37R, 41R, 42R, 43R, 45R, 46R, 47R, 48S, and 49S.

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“…Among many different micromixers designed for microflow systems, a Comet X-01 micromixer should be highlighted. This mixer has previously been used to perform and optimize various reactions [4,[97][98][99][100][101][102][103][104][105][106][107][108][109][110][111][112][113][114]. Inside this mixer, the flow is split into three and merged back into one (repeated five times) (see Figure 5 and supporting information file for Ref.…”

Section: Systems (Vide Infra)mentioning

confidence: 99%

Mixer Design and Flow Rate as Critical Variables in Flow Chemistry Affecting the Outcome of a Chemical Reaction: A Review

Myachin,

Kononov

2023

Inventions

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Flow chemistry offers several advantages for performing chemical reactions and has become an important area of research. It may seem that sufficient knowledge has already been acquired on this topic to understand how to choose the design of microreactor/micromixer and flow rate in order to achieve the desired outcome of a reaction. However, some experimental data are difficult to explain based on commonly accepted concepts of chemical reactivity and performance of microfluidic systems. In this mini review, we attempt to identify such data and offer a rational explanation of unusual results based on the supramer approach. We demonstrate that variation in flow regime (determined by mixer design and flow rate) can either improve or worsen the reactivity and lead to completely different products, including stereoisomers. It is not necessary to mix the reagents with maximum efficiency. The real challenge is to mix reagents the right way since at a too high or too low flow rate (in the particular mixer), the molecules of reagents are incorrectly presented on the surface of supramers, leading to altered stereoselectivity, or form tight supramers, in which most of the molecules are located inside the supramer core and are inaccessible for attack, leading to low yields.

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Flow Synthesis of (3R)- and (3S)-(E)-1-Iodohexa-1,5-dien-3-ol: Chiral Building Blocks for Natural Product Synthesis

Cited by 12 publications

References 28 publications

Preparation of Tenuifolin from Polygala senega L. Root Using a Hydrolytic Continuous Flow System under High-Temperature, High-Pressure Conditions

Preparation of Tenuifolin from Polygala senega L. Root Using a Hydrolytic Continuous Flow System under High-Temperature, High-Pressure Conditions

Synthesis and Stereochemistry of the C30−C63 Section of Karlotoxin 2

Mixer Design and Flow Rate as Critical Variables in Flow Chemistry Affecting the Outcome of a Chemical Reaction: A Review

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