Acetoxy Meldrum’s Acid: A Versatile Acyl Anion Equivalent in the Pd-Catalyzed Asymmetric Allylic Alkylation

Trost, Barry M.; Osipov, Maksim; Kaib, Philip S. J.; Sorum, Mark T.

doi:10.1021/ol2011242

Cited by 26 publications

(15 citation statements)

References 34 publications

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“…Trost’s group also demonstrated that acetoxy Meldrum’s acid can be used as a versatile acyl anion equivalent in the Pd-catalyzed allylic alkylation of meso - and racemic cyclic substrates. 98 Thus, 5- to 7-membered ring meso -substrates were desymmetrized with high enantioselectivity using the Pd/( R , R )-DACH-phenyl catalyst ( ee values up to 99%; Scheme 23 a). The resulting compounds were then converted to a variety of products by a second allylic substitution with several N- and O-nucleophiles using Pd/( rac )-DACH-phenylas catalyst ( Scheme 23 b).…”

Section: Asymmetric Allylic Substitutionmentioning

confidence: 99%

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

Pàmies

Margalef

Cañellas³

et al. 2021

Chem. Rev.

411

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 Allylic Substitutionmentioning

confidence: 99%

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

Pàmies

Margalef

Cañellas³

et al. 2021

Chem. Rev.

411

202

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“…[107] Another notable carbonyl synthoni sa cetoxy Meldrum's acid, which after alkylation can be converted to ac arboxylic acid by oxidative hydrolysis (Scheme 66 c). [108] Interestingly,t his useful reaction is rarely used, much like the analogousb is(sulfone)-based transformation presented in Scheme 56.…”

Section: Other Carbonyl Equivalentsmentioning

confidence: 99%

“…Malonates have also been investigated as acyl anion equivalents, but are less attractive than dithianes since like bis(sulfones), they require multiple steps to unmask (Scheme b) . Another notable carbonyl synthon is acetoxy Meldrum's acid, which after alkylation can be converted to a carboxylic acid by oxidative hydrolysis (Scheme c) . Interestingly, this useful reaction is rarely used, much like the analogous bis(sulfone)‐based transformation presented in Scheme .…”

Section: Comparing Bis(sulfones) To Other Masked Synthonsmentioning

confidence: 99%

Sulfones as Chemical Chameleons: Versatile Synthetic Equivalents of Small‐Molecule Synthons

Trost

Kalnmals

2019

Chemistry A European J

Self Cite

129

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Sulfones are flexible functional groups that can act as nucleophiles, electrophiles, or even radicals. Changing the reaction conditions can completelya lter the reactivity of as ulfonyl group, and as ar esult, molecules bearing multiple sulfones are versatile building blocks. This Review highlights the unique ability of 1,1-and 1,2-bis(sulfones) to masquerade as av ast array of reactive synthons includingm ethane polyanions, vinyl cations,a nd all-carbond ipoles that would be difficultori mpossible to access directly.Scheme1.Selectedsyntheses and reactions of sulfones.Scheme2.Seminaluse of abis(sulfone) as am ethanedianion equivalent.[a] Prof. 11195 MinireviewScheme5.Pd-catalyzed allylic alkylation reactionsw ith bis(sulfones) as methylanion equivalents.Scheme6.Mitsunobumethylationfacilitated by ab is(sulfone) nucleophile.Scheme7.Formal methyl conjugate additiont oa,b-unsaturated aldehydes.Scheme8.Formal methyl conjugate additiont oa na,b-unsaturated ketone.Scheme11. Organocatalytic asymmetric allylic alkylation of Morita-Baylis-Hillmanc arbonates with FBSM.Scheme12. Formal asymmetric fluoromethylationofa ldimines.Scheme13. Formal asymmetric fluoromethylationofa ldehydes.Scheme14. Formal fluoromethylconjugate additionst oenals.Scheme15. Formal fluoromethylconjugate addition to enones.Scheme16. Alkylation of FBSM with alcohols and alkyl halides.Scheme17. Differential reactivity of BDT in difficult alkylation reactions.Scheme18. Annulative Mitsunobu reactionswith bis(sulfone) nucleophiles.Scheme19. Macrocyclizationr eactionsf acilitated by bis(sulfones). Scheme20. Syntheses of insect pheromones facilitated by bis(sulfones).Scheme21. To talsynthesis of (À)-trans-lauthisan.Scheme22. To talsyntheses of constanolactones Aand B.Scheme56. Usingabis(sulfone) to access an ambiphilic carbonyl synthon.Scheme57. Usingabis(sulfone) to access ac arbonyl diradical synthon.Scheme58. Syntheses of (AE)-21-noribogamineand (AE)-ibogamine facilitated by using abis(sulfone) as areplacement for lowmolecular weight olefins.

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“…More recently, Trost described the use of acetoxy Meldrum's acid as an acyl anion equivalent in the enantioselective palladium-catalyzed allylic alkylation and applied this methodology to the synthesis of several biologically active nucleoside analogues. 85 However, a three-step sequence is required to unmask the desired carbonyl functionality, which limits the synthetic utility of this process.…”

Section: Equation 37mentioning

confidence: 99%

Transition-Metal-Catalyzed Allylic Substitution Reactions: Stereoselective Construction of α- and β-Substituted Carbonyl Compounds

2013

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The stereoselective synthesis of α-and β-substituted carbonyl compounds remains a significant area of interest in organic chemistry. This is largely due to their ubiquity and versatility as synthetic intermediates and the importance of this functionality in a range of biologically important agents. In this context, the transition-metal-catalyzed allylic substitution provides an extremely powerful tool for the asymmetric construction of a variety of α-and β-tertiary and quaternary substituted carbonyl compounds. This review highlights pertinent historical developments of these reactions, from the seminal work with enolate equivalents to the more recent developments with unstabilized enolates and acyl anions. It also outlines the most important mechanistic aspects of these transformations in order to provide insight into the current scope and limitations and potential areas for further development.

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Acetoxy Meldrum’s Acid: A Versatile Acyl Anion Equivalent in the Pd-Catalyzed Asymmetric Allylic Alkylation

Cited by 26 publications

References 34 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

Sulfones as Chemical Chameleons: Versatile Synthetic Equivalents of Small‐Molecule Synthons

Transition-Metal-Catalyzed Allylic Substitution Reactions: Stereoselective Construction of α- and β-Substituted Carbonyl Compounds

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