Improved Synthesis of Racemate and Enantiomers of Taniguchi Lactone and Conversion of Their C–C Double Bonds into Triple Bonds

Križková, Petra Malová; Lindner, Wolfgang; Hammerschmidt, Friedrich

doi:10.1055/s-0036-1591516

“…The synthetic routes of target compounds A0 – A31 and B0 – B4 are depicted in Figure . The alkenes 4a and 4b were proposed to be the key intermediates, which could be obtained by aldol condensation, reduction, and acid-catalyzed cyclization reactions from Taniguchi lactone ( 1 ). , Using lithium diisopropylamide (LDA) as base, the aldol condensation of lactone 1 with the corresponding aldehyde ( 2a or 2b ) gave the α-substituted γ-lactone, which was successfully reduced by lithium aluminum hydride (LiAlH 4 ) in THF at 60 °C. The corresponding triol ( 3a or 3b , a mixture of two diastereomers) was obtained in a good yield.…”

Section: Resultsmentioning

confidence: 99%

Furofuran Lignans for Plant Protection: Discovery of Sesamolin and Its Derivatives as Novel Anti-Tobacco Mosaic Virus and Antibacterial Agents

Chi

¹

,

He

²

,

Chen

³

et al. 2023

J. Agric. Food Chem.

2

0

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Natural products have been a valuable source of efficient and low-risk pesticides. In this work, a series of novel sesamolin derivatives A0–A31 and B0–B4 were designed and synthesized via structural simplification of furofuran lignan phrymarolin II, and their antiviral and antibacterial activities were systematically evaluated. The bioassay results showed that compound A24 displayed remarkable inactivation activity against tobacco mosaic virus (TMV) with an EC50 value of 130.4 μg/mL, which was superior to that of commercial ningnanmycin (EC50 = 202.0 μg/mL). The antiviral mode of action assays suggested that compound A24 may obstruct self-assembly by binding to TMV coat protein (CP), thus resisting the TMV infection. In addition, compound A25 possessed prominent antibacterial activities, especially against Ralstonia solanacearum with an EC50 value of 43.8 μg/mL, which is better than those of commercial bismerthiazol and thiodiazole copper. This research lays a solid foundation for the utilization of furofuran lignans in crop protection.

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“…In contrast, elimination of vicinal dihalides to alkenylhalides suffers from both poor regio-and stereoselectivity, yielding difficult to separate mixtures. [29][30][31] To circumvent this problem, alkenylhalides are more commonly prepared from the corresponding alkynes rather than alkenes. [32][33][34] Further-more, reactions have been developed to substitute alkenylthianthrenium salts at both the ipso and cine position, offering a stark contrast to the ipso substitution chemistry of alkenylhalides.…”

Section: Alkenes As Alkenyl Cation Equivalentsmentioning

confidence: 99%

“…Elimination of dicationic thianthrenium salts provides exclusively the linear regioisomer with high selectivity for the E ‐stereoisomer. In contrast, elimination of vicinal dihalides to alkenylhalides suffers from both poor regio‐ and stereoselectivity, yielding difficult to separate mixtures [29–31] . To circumvent this problem, alkenylhalides are more commonly prepared from the corresponding alkynes rather than alkenes [32–34] .…”

Section: Alkenes As Alkenyl Cation Equivalentsmentioning

confidence: 99%

Alkene Thianthrenation Unlocks Diverse Cation Synthons: Recent Progress and New Opportunities

Kim,

Targos,

Holst

et al. 2024

Angewandte Chemie

0

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Oxidative alkene functionalization reactions are a fundamental class of complexity‐building organic transformations. However, the majority of established approaches rely on electrophilic reagents that limit the diversity of groups that can be installed. Recent advances have established a new approach that instead relies on the transformation of alkenes into thianthrene‐derived cationic electrophiles. These linchpin intermediates can be generated selectively and undergo a diverse array of mechanistically distinct reactions with abundant nucleophiles. Taken together, this unlocks a suite of net oxidative alkene transformations that have been elusive using conventional strategies. This Minireview describes these advances and is organized around the three distinct synthons formally accessible from alkenes via thianthrenation: 1) alkenyl cations; 2) vicinal dications; 3) allyl cations. Throughout the Minireview, we illustrate how thianthrenium salts address key limitations endemic to classic alkene‐derived electrophiles and highlight the mechanistic origins of these distinctions wherever possible.

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Alkene Thianthrenation Unlocks Diverse Cation Synthons: Recent Progress and New Opportunities

Kim,

Targos,

Holst

et al. 2024

Angew Chem Int Ed

7

0

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Oxidative alkene functionalization reactions are a fundamental class of complexity‐building organic transformations. However, the majority of established approaches rely on electrophilic reagents that limit the diversity of groups that can be installed. Recent advances have established a new approach that instead relies on the transformation of alkenes into thianthrene‐derived cationic electrophiles. These linchpin intermediates can be generated selectively and undergo a diverse array of mechanistically distinct reactions with abundant nucleophiles. Taken together, this unlocks a suite of net oxidative alkene transformations that have been elusive using conventional strategies. This Minireview describes these advances and is organized around the three distinct synthons formally accessible from alkenes via thianthrenation: 1) alkenyl cations; 2) vicinal dications; 3) allyl cations. Throughout the Minireview, we illustrate how thianthrenium salts address key limitations endemic to classic alkene‐derived electrophiles and highlight the mechanistic origins of these distinctions wherever possible.

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Improved Synthesis of Racemate and Enantiomers of Taniguchi Lactone and Conversion of Their C–C Double Bonds into Triple Bonds

Cited by 6 publications

References 8 publications

Furofuran Lignans for Plant Protection: Discovery of Sesamolin and Its Derivatives as Novel Anti-Tobacco Mosaic Virus and Antibacterial Agents

Furofuran Lignans for Plant Protection: Discovery of Sesamolin and Its Derivatives as Novel Anti-Tobacco Mosaic Virus and Antibacterial Agents

Alkene Thianthrenation Unlocks Diverse Cation Synthons: Recent Progress and New Opportunities

Alkene Thianthrenation Unlocks Diverse Cation Synthons: Recent Progress and New Opportunities

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