Total Synthesis of (±)‐Phomoidride D

Leung, Joyce C.; Bedermann, Aaron A.; Njardarson, Jón T.; Spiegel, David A.; Murphy, Graham K.; Hama, Naoto; Twenter, Barry M.; Dong, Ping; Shirahata, Tatsuya; McDonald, Ivar M.; Inoue, Munenori; Taniguchi, Nobuaki; McMahon, Travis C.; Schneider, Christopher; Tao, Nancy; Stoltz, Brian M.; Wood, John L.

doi:10.1002/ange.201712369

Cited by 24 publications

(7 citation statements)

References 33 publications

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“… 3 Intramolecular processes using the commercially available reagent are particularly popular, and SmI 2 -mediated radical cyclizations feature in the total synthesis of numerous high profile and complex natural products. 4 Intermolecular processes using SmI 2 are inherently more challenging as intermolecular radical C–C bond formation must outrun the competing reduction of radicals to carbanions. While the chemistry of SmI 2 is very often unique, and thus the reagent is indispensable, 2 − 4 it is almost invariably used in superstoichiometric amounts, thus raising issues of cost and waste.…”

Section: Introductionmentioning

confidence: 99%

“… 4 Intermolecular processes using SmI 2 are inherently more challenging as intermolecular radical C–C bond formation must outrun the competing reduction of radicals to carbanions. While the chemistry of SmI 2 is very often unique, and thus the reagent is indispensable, 2 − 4 it is almost invariably used in superstoichiometric amounts, thus raising issues of cost and waste. Of the few reports of the use of catalytic SmI 2 , all require the use of superstoichiometric amounts of a metal coreductant to regenerate Sm(II).…”

Section: Introductionmentioning

confidence: 99%

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SmI₂-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity

et al. 2021

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The archetypal single electron transfer reductant, samarium(II) diiodide (SmI 2 , Kagan’s reagent), remains one of the most important reducing agents and mediators of radical chemistry after four decades of widespread use in synthesis. While the chemistry of SmI 2 is very often unique, and thus the reagent is indispensable, it is almost invariably used in superstoichiometric amounts, thus raising issues of cost and waste. Of the few reports of the use of catalytic SmI 2 , all require the use of superstoichiometric amounts of a metal coreductant to regenerate Sm(II). Here, we describe a SmI 2 -catalyzed intermolecular radical coupling of aryl cyclopropyl ketones and alkynes. The process shows broad substrate scope and delivers a library of decorated cyclopentenes with loadings of SmI 2 as low as 15 mol %. The radical relay strategy negates the need for a superstoichiometric coreductant and additives to regenerate SmI 2 . Crucially, our study uncovers an intriguing link between ketone conformation and efficient cross-coupling and thus provides an insight into the mechanism of radical relays involving SmI 2 . The study lays further groundwork for the future use of the classical reagent SmI 2 in contemporary radical catalysis.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

SmI₂-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity

et al. 2021

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“…[19] Lastly, palladium mediated carbonylation of β-keto ester IX derived enol triflates represents a powerful method for the direct access of anhydride moieties. [20] This sequence was successfully applied in Wood's synthesis of phomoidride D. [21]…”

Section: Resultsmentioning

confidence: 99%

Evolution of a Strategy for the Total Synthesis of (+)‐Cornexistin

Wildermuth

Steinborn

Barber

et al. 2021

Chemistry A European J

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Herein is given a full account of the evolution of the first total synthesis of (+)‐cornexistin. Initial efforts were based on masking the reactive maleic anhydride moiety as a 3,4‐substituted furan and on forming the nine‐membered carbocycle in an intramolecular Conia‐ene or Nozaki–Hiyama–Kishi (NHK) reaction. Those strategies suffered from low yields and were jeopardized by a late‐stage installation of the Z‐alkene, as well as the stereocenters along the eastern periphery. These issues were addressed by employing a chiral‐pool strategy that involved construction of the crucial stereocenters at C2, C3 and C8 at an early stage with installation of the maleic anhydride as late as possible. The successful approach featured an intermolecular NHK coupling to install the Z‐alkene, a syn‐Evans‐aldol reaction to forge the stereocenters along the eastern periphery, an intramolecular allylic alkylation to close the nine‐membered carbocycle, and a challenging stepwise hydrolysis of a β‐keto nitrile to furnish the maleic anhydride.

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“…3 Although acylations of sterically hindered enolates with Mander’s reagent are prone to scramble between C - and O -selectivity, 4 C -selectivity can be enforced by adjusting the reaction conditions. 4a 5…”

Section: Table 1 Screening For the Deoxycyanation Of ...mentioning

confidence: 99%

Mander’s Reagent for the Deoxycyanation of β-Diketones: A Direct Synthesis of Oxoalkenenitriles

Cruz-Jiménez¹,

Mateus-Ruiz²,

Silva-Cuevas³

et al. 2022

Synlett

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Ethyl and methyl cyanoformate (Mander’s reagent) are reagents to routinely perform C-selective ketone alcoxycarbonylations. Interestingly, both reagents were found to yield oxoalkenenitriles through an unprecedented deoxycyanation on 1,3-dicarbonyl compounds (e. g. 2-methyl-1,3-cyclohexanedione). Although this method was not general, this is the first time both Mander’s reagent and ethyl cyanoformate were used for the deoxycyanation of 1,3-dicarbonyl compounds for the preparation of synthetically useful oxoalkenenitriles. Limitations on the substrate scope for the present methodology are discussed.

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Total Synthesis of (±)‐Phomoidride D

Cited by 24 publications

References 33 publications

SmI₂-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity

SmI₂-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity

Evolution of a Strategy for the Total Synthesis of (+)‐Cornexistin

Mander’s Reagent for the Deoxycyanation of β-Diketones: A Direct Synthesis of Oxoalkenenitriles

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Total Synthesis of (±)‐Phomoidride D

Cited by 24 publications

References 33 publications

SmI2-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity

SmI2-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity

Evolution of a Strategy for the Total Synthesis of (+)‐Cornexistin

Mander’s Reagent for the Deoxycyanation of β-Diketones: A Direct Synthesis of Oxoalkenenitriles

Contact Info

Product

Resources

About

SmI₂-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity

SmI₂-Catalyzed Intermolecular Coupling of Cyclopropyl Ketones and Alkynes: A Link between Ketone Conformation and Reactivity