Palladium‐Catalyzed Asymmetric Decarboxylative Allylation of Azlactone Enol Carbonates: Fast Access to Enantioenriched α‐Allyl Quaternary Amino Acids

Serra, Massimo; Bernardi, Eric; Marrubini, Giorgio; Lorenzi, Ersilia De; Colombo, Lino

doi:10.1002/ejoc.201801363

Cited by 16 publications

(12 citation statements)

References 45 publications

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“…Shibasaki, Noda, and later Stoltz utilized the DAAA reaction as the key enantiodetermining step in the development of quaternary β 2,2 -amino acids ( Schemes 217 and 228 ). Colombo also applied this method to the enantioselective synthesis of quaternary α 2,2 -amino acids, 608 using azlactone enol carbonates as substrates, which can be accessed in 33% to 89% overall yield from commercially available tertiary amino acids in three steps ( Scheme 229 ). Among the range of ligands tested, Trost’s ligand ( R , R )-Ph-DACH gave the highest enantioselectivity (70% ee ) for the phenylglycine-derived model substrate.…”

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.

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 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.

411

202

View full text Add to dashboard Cite

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“…In fact, the separation and purification of azlactone substrates are a relatively tedious operation during their preparation . In order to avoid this tedious operation and conveniently use this kind of compounds in organic synthesis, we attempted to develop a one-pot protocol to synthesize the 4,5-dihydropyridazin-3(2 H )-ones by using the in situ formed azlactones and the in situ generated azoalkenes.…”

Section: Results and Discussionmentioning

confidence: 99%

[4 + 2] Annulation Reaction of In Situ Generated Azoalkenes with Azlactones: Access to 4,5-Dihydropyridazin-3(2H)-Ones

et al. 2020

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An unprecedented [4 + 2] annulation reaction between in situ formed azoalkenes and azlactones has been developed. This reaction provides a facile access to an array of 4,5dihydropyridazin-3(2H)-one derivatives, which are very promising in medicinal applications as potential biologically active candidates. Notably, these dihydropyridazinones could also be synthesized via a one-pot reaction protocol by using the in situ formed azlactones from N-acyl amino acids and in situ generated azoalkenes from αhalogeno hydrazones. The potential applications of the methodology were also demonstrated by gram-scale experiments and the versatile conversions of the products into other nitrogen-containing compounds.

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“…Recently, Colombo's group reported that the reaction between azlactones ( 234 ) and allyl chloroformates enabled the access to stable allyl enol carbonates ( 235 ) . These intermediates were then submitted to an enantioselective Pd‐catalyzed Tsuji decarboxylative allylation, affording the desired 4‐allyl oxazol‐5‐ones ( 236 ) in good to excellent yields (up to 98 %) and low to good enantioselectivities (ranging from 30 to 85 % ee ) (Scheme A).…”

Section: Conjugate Additions and Other Enolate‐mediated Reactionsmentioning

confidence: 99%

Recent Advances in Azlactone Transformations

2019

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Azlactones, also known as oxazolones, are versatile building blocks in organic synthesis due to the presence of multiple pro‐nucleophilic and electrophilic reactive sites. Recently, several elegant organo‐ and metal‐catalyzed studies have been described, allowing the stereocontrolled access to complex structures in only one or a few chemical steps. Moreover, the development of one‐pot, tandem and domino reactions greatly enhanced the azlactone scaffold potential. In this context, this review aims to cover novel methodologies, including a brief overview of oxazolones and Erlenmeyer azlactones preparation. New approaches towards classical reactions, such as dynamic kinetic resolution, cycloadditions, and conjugate additions will be presented as well as new methodologies involving photochemical and flow chemistry technology. Finally, for most studies, selected examples will be presented and mechanistic pathways and/or activating modes will be carefully discussed.

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Palladium‐Catalyzed Asymmetric Decarboxylative Allylation of Azlactone Enol Carbonates: Fast Access to Enantioenriched α‐Allyl Quaternary Amino Acids

Cited by 16 publications

References 45 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

[4 + 2] Annulation Reaction of In Situ Generated Azoalkenes with Azlactones: Access to 4,5-Dihydropyridazin-3(2H)-Ones

Recent Advances in Azlactone Transformations

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