Short Enantioselective Formal Synthesis of (–)-Platencin

Defieber, Christian; Mohr, Justin T.; Grabovyi, Gennadii A.; Stoltz, Brian M.

doi:10.1055/s-0037-1610437

Cited by 10 publications

(2 citation statements)

References 77 publications

(18 reference statements)

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“…The Pd-catalyzed DAAA was also used to synthesize β-keto ester 249 as the key intermediate in the enantioselective formal synthesis of the natural antibiotic (−)-platencin ( Scheme 265 ). 665 From chiral intermediate 249 , a radical-mediated cyclization led to the formation of the bicyclo[2.2.2]octane core that was further transformed to tricyclic intermediate 250 via a regioselective aldol cyclization. Compound 250 , which was prepared in 3.5% overall yield, had been previously converted to the target (−)-platencin.…”

Section: Asymmetric Decarboxylative Allylic Substitutionmentioning

confidence: 99%

Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Pàmies

Margalef

Cañellas³

et al. 2021

Chem. Rev.

360

202

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This Review compiles the evolution, mechanistic understanding, and more recent advances in enantioselective Pd-catalyzed allylic substitution and decarboxylative and oxidative allylic substitutions. For each reaction, the catalytic data, as well as examples of their application to the synthesis of more complex molecules, are collected. Sections in which we discuss key mechanistic aspects for high selectivity and a comparison with other metals (with advantages and disadvantages) are also included. For Pd-catalyzed asymmetric allylic substitution, the catalytic data are grouped according to the type of nucleophile employed. Because of the prominent position of the use of stabilized carbon nucleophiles and heteronucleophiles, many chiral ligands have been developed. To better compare the results, they are presented grouped by ligand types. Pd-catalyzed asymmetric decarboxylative reactions are mainly promoted by PHOX or Trost ligands, which justifies organizing this section in chronological order. For asymmetric oxidative allylic substitution the results are grouped according to the type of nucleophile used.

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Section: Asymmetric Decarboxylative Allylic Substitutionmentioning

confidence: 99%

Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Pàmies

Margalef

Cañellas³

et al. 2021

Chem. Rev.

360

202

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“… 1 For example, the combination of acyl anion equivalents with the asymmetric transition metal-catalyzed allylic alkylation reaction (AAA) 2 – 5 provides an attractive strategy for the construction of acyclic α-ternary β,γ-unsaturated carbonyl derivatives ( Scheme 1A ). Although this approach avoids some of the challenges associated with asymmetric enolate alkylation, namely, polyalkylation, epimerization and electrophile scope, 6 – 8 the reaction requires the construction of an intermediate that can either suppress the isomerization of the olefin to the thermodynamically more stable α,β-unsaturated derivative or requires the removal of the olefin prior to the unveiling of the carbonyl motif. 9 In addition, many of the acyl anion equivalents that have been successfully deployed in the asymmetric transition metal-catalyzed allylic alkylation reaction require additional functionalization steps to reveal the carbonyl moiety at the desired oxidation state, which detracts from the overall efficiency and utility of this approach ( Scheme 1B ).…”

Section: Introductionmentioning

confidence: 99%

Regio- and stereospecific rhodium-catalyzed allylic alkylation with an acyl anion equivalent: an approach to acyclic α-ternary β,γ-unsaturated aryl ketones

et al. 2017

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The Catalytic Enantioselective Stetter Reaction

Flanigan¹,

Ozboya²,

Tanpure³

et al. 2021

Organic Reactions

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The catalytic enantioselective Stetter reaction is the coupling of an aldehyde with an electron‐deficient alkene via the conjugate addition of an acyl anion equivalent (Breslow intermediate) generated from the aldehyde and a chiral N ‐heterocyclic carbene (NHC) catalyst. The process affords 1,4‐dicarbonyl compounds and related systems, such as β‐nitroketones, in an efficient and atom‐economical fashion and with generally good‐to‐excellent enantioselectivities when fused polycyclic chiral triazolylidenes are employed as the NHC catalysts. The scope of the transformation is particularly broad for intramolecular reactions, but in the case of the intermolecular variant, only certain types of aldehyde donors and electrophilic alkenes can be successfully coupled together. This chapter describes theoretical and operational aspects of the catalytic enantioselective Stetter reaction such that the reader will be able to obtain optimal results in their own research. A detailed mechanistic overview is included to account for the factors that influence stereoselectivity and yield, and results from experimental and computational mechanistic studies are summarized. In addition, catalyst synthesis, reaction variants, applications in target‐directed synthesis, and comparison to other methods for generating 1,4‐dicarbonyl compounds are also presented. Tabular surveys are organized according to the modality of reactivity, either intra‐ or intermolecular, and the type of aldehyde donor. The literature is covered from the first disclosure of a catalytic enantioselective Stetter reaction in 1996 through to the end of 2019.

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Short Enantioselective Formal Synthesis of (–)-Platencin

Abstract: A short enantioselective formal synthesis of the antibiotic natural product platencin is reported. Key steps in the synthesis include enantioselective decarboxylation alkylation, aldehyde/olefin radical cyclization, and regioselective aldol cyclization.

Cited by 10 publications

References 77 publications

Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Regio- and stereospecific rhodium-catalyzed allylic alkylation with an acyl anion equivalent: an approach to acyclic α-ternary β,γ-unsaturated aryl ketones

The Catalytic Enantioselective Stetter Reaction

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