Modular Total Syntheses of Hyperforin, Papuaforins A, B, and C via Gold(I)-Catalyzed Carbocyclization

Bellavance, Gabriel; Barriault, Louis

doi:10.1021/acs.joc.8b00426

Cited by 27 publications

(26 citation statements)

References 44 publications

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“…A key carbocyclization involving a bromoynone and a silyl enol ether was employed by Barriault and coworkers in their elegant and straightforward synthesis of several polyprenylated polycyclic acylphloroglucinols (PPAPs) (Scheme 111). 193,194 By treatment with a catalytic quantity of [(JohnPhos)Au-(NCMe)]SbF 6 (5 mol %), substrates 484a−c could be easily cyclized to produce the bicyclo[3.3.1]nonane framework of the targeted natural products. Compounds 485a−c were found to be ideal platforms for further functionalization toward the synthesis of PPAPs.…”

Section: Alkynyl Carbonyl Derivativesmentioning

confidence: 99%

Gold-Catalyzed Reactions of Specially Activated Alkynes, Allenes, and Alkenes

et al. 2020

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This review describes the gold-catalyzed reactions of specially activated alkynes, allenes, and alkenes. Such species are characterized by the presence of either electron-donating or electron-withdrawing groups as substituents of the carbon π-system. They are intrinsically polarized, and when compared to their nonspecially activated counterparts can therefore be involved in gold-catalyzed transformations featuring increased regio-, stereo-, and chemoselectivities. The chemistry of specially activated carbon π-systems under homogeneous gold catalysis is extremely rich and varied. The reactivity observed with nonspecially activated unsaturated systems can often be transposed to specially activated ones without loss of efficiency. However, specially activated carbon π-systems also exhibit specific reactivities that cannot be attained with regular substrates. In this family of carbon π-systems, ynamides and their analogs, along with alkynyl carbonyl derivatives, are the classes of substrates that have retained the most attention. This review provides an overview of the chemistry developed with all classes of specially activated carbon π-systems by discussing their general and specific reactivities, presenting and commenting on their gold-catalyzed transformations as well as their applications.

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Section: Alkynyl Carbonyl Derivativesmentioning

confidence: 99%

Gold-Catalyzed Reactions of Specially Activated Alkynes, Allenes, and Alkenes

et al. 2020

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“…These are polyprenylated polycyclic acylphloroglucinols with oxygenatedbicyclo[3.3.1]‐nonanone framework decorated with different functionalities. Hyperforin 681 exhibits antimetastatic, antimalarial, and antibacterial activities toward MRSA bacteria with a minimal inhibitory concentration of 1.86 μmol [285] . In this novel strategy, CM was used to convert mono‐subsituted alkene moieties to tri‐subsituted alkene moieties.…”

Section: Cross Metathesis (Cm)mentioning

confidence: 99%

“…Hyperforin 681 exhibits antimetastatic, antimalarial, and antibacterial activities toward MRSA bacteria with a minimal inhibitory concentration of 1.86 μmol. [285] In this novel strategy, CM was used to convert mono-subsituted alkene moieties to tri-subsituted alkene moieties. The journey for their synthesis began with the LDA-mediated addition of allybromide to enone 673 in presence of Li(2-Th)CuCN to deliver a diene 674, which underwent to double-CM with i-amylene in presence of G-II catalyst to produce the compound 675 in 99% yield.…”

Section: Total Synthesis Of Natural Products Based On CMmentioning

confidence: 99%

Metathesis Reactions in Natural Product Fragments and Total Syntheses

et al. 2022

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The passion of total‐ and fragments syntheses of natural products always remained one of the top priorities among the synthetic chemists worldwide. Due their curiosity toward the complexity of molecules of living nature and their endeavour to imitate them in laboratory; limitless arrays of natural products have been extracted, architecturally‐elucidated, synthesized, and chronicled by utilizing various synthetic methodologies in different fashions. Frequently, the synthesis of complex natural products proceed with inscrutable synthetic challenges, which can be circumvented either by modification of previously developed synthetic methods or by formulating a new one. In this way, a myriad of powerful synthetic reactions have been developed since the genesis of the logic of chemical synthesis. Amongst them, metathesis tactics discovered unexpectedly in the 1950s (Nobel Prize in 2005), have incredibly influenced and changed the landscape of the art of the total and formal synthesis in the last three A. H. Hoveyda, A. R. Zhugralin, me abruptly as compared to other developed transformations or their modified forms. In this particular review article, we envisioned to report a comprehensive detail of the metathetic tools involved in both total and fragments synthesis of natural products in the years 2018 and 2019 along with an overview of 2017.

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“…Indeed, Porco was able to validate this biosynthetic hypothesis, by designing a biomimetic cascade reaction that entailed the oxidation of a starting alcohol (not shown) into the enantiopure quinone epoxide 3 as a trigger for the spontaneous disrotatory oxa-6π electrocyclization and the ensuing dimerization (Scheme 2) [23,24]. A related strategy of mild oxidation as a means to produce a reactive oxatriene moiety and initiate an oxa-6π electrocyclic reaction in tandem was recently reported in a route towards the papuaforin A-C natural products [25]. The exquisite diastereoselectivity observed in the heterodimer product 5 was consistent with the theoretical energy-minima calculations from several competitive reaction pathways, reaction intermediates, and transition states computed on a model substrate at B3LYP/6-31G* level of theory.…”

Section: π-Electrocyclization/diels−alder Cycloaddition Cascade: the Domino Effectmentioning

confidence: 99%

Recent Advances in Oxa-6π Electrocyclization Reactivity for the Synthesis of Privileged Natural Product Scaffolds

Roche

2021

Organics

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The stunning advances in understanding the reactivity and selectivity principles of asymmetric pericyclic reactions have had a profound impact on the synthetic planning of complex natural products. Indeed, electrocyclizations, cycloadditions, and sigmatropic rearrangements enable synthetic chemists to craft highly functionalized scaffolds that would not otherwise be possible with a similar atom-, step-, and redox-economy. In this review, selected examples from the last two decades of research (2003–2020) on tandem processes combining oxa-6π electrocyclic reactions are discussed in terms of reactivity challenges, inherent reversibility, and key structural bond formation in the assembly of natural products. A particular emphasis is given to the electrocyclic ring-closures in the tandem processes featuring Knoevenagel-type condensations, Diels–Alder cycloadditions, Stille couplings, and oxidative dearomatizations. The synthetic manifolds reviewed here illustrate how oxa-6π electrocyclizations are intimately linked to the construction of complex natural product scaffolds and have inspired a number of biomimetic syntheses in the laboratory.

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Modular Total Syntheses of Hyperforin, Papuaforins A, B, and C via Gold(I)-Catalyzed Carbocyclization

Cited by 27 publications

References 44 publications

Gold-Catalyzed Reactions of Specially Activated Alkynes, Allenes, and Alkenes

Gold-Catalyzed Reactions of Specially Activated Alkynes, Allenes, and Alkenes

Metathesis Reactions in Natural Product Fragments and Total Syntheses

Recent Advances in Oxa-6π Electrocyclization Reactivity for the Synthesis of Privileged Natural Product Scaffolds

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