Expeditious Synthesis of the Cores of Naturally Occurring Cyclic Polyethers using a Divergent Ring Rearrangement Metathesis Strategy

Escavabaja, Philippe; Viala, Jacques; Coquerel, Yoann; Rodríguez, Jean

doi:10.1002/adsc.201200665

Cited by 9 publications

(4 citation statements)

References 52 publications

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“…1,2-Reduction of an enone, then O-allylation delivers an alternative entry to metathesis substrates that lead to 2-substituted-2,5-DHFs. This strategy formed part of a stereochemically flexible approach to bis-THF containing acetogenins (Scheme 3), 10 where the enones (e.g., 4) were derived from regio-and stereo-selective [5 + 2] cycloaddition of in situ generated 3-oxidopyrylium (3) with alkene dipolarophiles. In these cases, the 2-substituted-2,5-DHF 6 is produced through strain relief-driven ring rearrangement metathesis (RRM), and is carried out in the presence of 1,4-benzoquinone under an ethylene atmosphere.…”

Section: 5-dihydrofuransmentioning

confidence: 99%

“…A second route to the 1,5-dioxaoctahydroindene core modifies the RRM chemistry outlined in Scheme 3, by using residual unsaturation originating from the dipolarophile component in the [5 + 2] cycloadduct (Scheme 39). 10 A metathesis-induced oxabicyclic rearrangement strategy related to that shown in Scheme 39 allowed a formal synthesis of dysiherbaine and neodysiherbaine (Scheme 40). 53 The metathesis substrate 134 was accessed from Diels-Alder cycloaddition of TBS-protected furfuryl alcohol and an unsaturated sulfone, followed by resolution.…”

Section: Scheme 31 Synthesis Of Phoslactomycin B (111)mentioning

confidence: 99%

“…For 2,2-disubstituted-2,5-DHFs, ketone C-vinylation-O-allylation provides a convenient approach to RCM substrates. For example, the tricyclic core 9 of hippolachnin A (10) was recently synthesised from a D-mannitol-derived RCM substrate 7 made in this way (Scheme 4). 11 Metathesis using GI likely initiated at the least hindered terminal olefin of the tetraene 7, with RCM occurring non-stereoselectively at the formally diastereotopic vinyl groups.…”

Section: Introductionmentioning

confidence: 99%

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Recent applications in natural product synthesis of dihydrofuran and -pyran formation by ring-closing alkene metathesis

et al. 2016

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In the past two decades, alkene metathesis has risen in prominence to become a significant synthetic strategy for alkene formation. Many total syntheses of natural products have used this transformation. We review the use, from 2003 to 2015, of ring-closing alkene metathesis (RCM) for the generation of dihydrofurans or -pyrans in natural product synthesis. The strategies used to assemble the RCM precursors and the subsequent use of the newly formed unsaturation will also be highlighted and placed in context.

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Section: 5-dihydrofuransmentioning

confidence: 99%

Section: Scheme 31 Synthesis Of Phoslactomycin B (111)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Recent applications in natural product synthesis of dihydrofuran and -pyran formation by ring-closing alkene metathesis

et al. 2016

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“…The Dysiherbaine and acetogenin groups of natural products have been synthesized by the RRM approach. In this regard, secondary alcohol derivatives related to 8-oxabicyclo[3.2.1]octenes such as 341a,b , c were used as potential precursors for the synthesis of a variety of cyclic polyethers [ 71 ]. Allylation of 340a–c using sodium hydride and allyl bromide ( 37 ) in the presence of a phase-transfer catalyst such as tetrabutylammonium iodide generated bicyclic compounds 341a–c .…”

Section: Reviewmentioning

confidence: 99%

Recent applications of ring-rearrangement metathesis in organic synthesis

Kotha¹,

Meshram²,

Khedkar³

et al. 2015

Beilstein J. Org. Chem.

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SummaryRing-rearrangement metathesis (RRM) involves multiple metathesis processes such as ring-opening metathesis (ROM)/ring-closing metathesis (RCM) in a one-pot operation to generate complex targets. RRM delivers complex frameworks that are difficult to assemble by conventional methods. The noteworthy point about this type of protocol is multi-bond formation and it is an atom economic process. In this review, we have covered literature that appeared during the last seven years (2008–2014).

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Expeditious Synthesis of Enantioenriched Tetrahydropyrans via Chemoselective C−N bond Cleavage of Aza‐Oxa‐Bicyclo[3.2.1]Octanes

et al. 2017

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A rapid synthesis of enantioenriched 2,3,4-trisubstituted tetrahydropyrans in good yields and stereoselectivities is reported. The first step is a domino organocatalytic reaction between ambident electrophilic and 1,4-bis-nucleophilic 1,2-ketoamides and 1,3-bis-electrophilic enals, leading to aza-oxa-bicyclo[3.2.1]octane. Then, the TiCl 4 /Et 3 SiH system ensures a chemoselective cleavage of the CÀN bond and affords the desired trisubstituted tetrahydropyran in good yield and with conservation of the precursors optical purity. This final synthetic operation includes two consecutive oxocarbenium ion formation and reductions.The tetrahydropyran (THP) core constitutes a central structural subunit found in many natural and unnatural products displaying a wide range of biological activities. [1] For this reason, the stereoselective preparation of such heterocycles has been the center of many efforts. [2] The most common strategies are based on the inter-and intramolecular CÀO [3] or CÀC [4] bond formations of the oxacycle. Other developed methodologies exploit the C-C bond fragmentations of the dihydrofuran ring in strained 8-oxabicyclo[3.2.1]octene intermediates, [5a-e] including enantioselective reactions. [ 5f, g] As a matter of fact, the implementation of straightforward enantioselective approaches for heterocycle syntheses is an attractive field of research and constitutes an important challenge of modern organic synthesis. [6] Recently, our group studied the chiral amine-catalyzed synthesis of optically active aza-oxa-bicyclo[3.2.1]octane 3 from simple achiral aketoamides 1 and enals 2. [7] These valuable synthetic platforms allowed us to further access functionalized azepanes 4 exploiting the lability of the CÀO bond (Scheme 1). [8] In this context, we disclose a new temporary-bridge strategy [9] based on a chemoselective CÀN bond cleavage leading to the formation of highly diastereo-and enantioselective construction of new functionalized tetrahydropyrans 5, bearing three consecutive stereogenic centers. Scheme 1. CÀN vs CÀO bond cleavage accessing to azepanes 4 or THPs 5 from bicyclic precursors 3.

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Expeditious Synthesis of the Cores of Naturally Occurring Cyclic Polyethers using a Divergent Ring Rearrangement Metathesis Strategy

Abstract: International audienceRing rearrangement metathesis (RRM) strategies are proposed for the expeditious synthesis of the cores of naturally occurring cyclic polyethers of the dysiherbaine and acetogenin families, as well as a hybrid compound, from 8-oxabicyclo- [3.2.1]octenes

Cited by 9 publications

References 52 publications

Recent applications in natural product synthesis of dihydrofuran and -pyran formation by ring-closing alkene metathesis

Recent applications in natural product synthesis of dihydrofuran and -pyran formation by ring-closing alkene metathesis

Recent applications of ring-rearrangement metathesis in organic synthesis

Expeditious Synthesis of Enantioenriched Tetrahydropyrans via Chemoselective C−N bond Cleavage of Aza‐Oxa‐Bicyclo[3.2.1]Octanes

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