Intramolecular arylation of amino acid enolates

Atkinson, Rachel C.; Leonard, Daniel J.; Maury, Julien; Castagnolo, Daniele; Volz, Nicole; Clayden, Jonathan

doi:10.1039/c3cc46193a

Cited by 34 publications

(37 citation statements)

References 53 publications

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“…Angewandte metadynamics and committor analysis methods have been studied by Moors et al [52] They found that for 4-nitrofluorobenzene (74), the reaction proceeded via ac oncerted mechanism in the gas phase via transition state 77,b ut via an intermediate Meisenheimer complex 83 in solution (Schemes 17 and 18). For4 -nitrochlorobenzene (75), the reaction proceeded via aconcerted mechanism via transition state 78 in both the gas phase and in solution, and for 2,4dinitrofluorobenzene (76), the reaction occurs via aM eisenheimer intermediate 79 in both solution and the gas phase.…”

Section: Methodsmentioning

confidence: 99%

Concerted Nucleophilic Aromatic Substitution Reactions

et al. 2019

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Recent developments in experimental and computational chemistry have identified a rapidly growing class of nucleophilic aromatic substitutions that proceed by concerted (cSNAr) rather than classical, two‐step, SNAr mechanisms. Whereas traditional SNAr reactions require substantial activation of the aromatic ring by electron‐withdrawing substituents, such activating groups are not mandatory in the concerted pathways.

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Section: Methodsmentioning

confidence: 99%

Concerted Nucleophilic Aromatic Substitution Reactions

et al. 2019

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“…The Clayden rearrangement suggests a direct route to α‐arylated non‐natural amino acids using amino acid derived ureas 125 . However, the direct transformation of ureas to these valuable products was complicated by hydantoin ( 126 ) formation following aryl migration of amino acid enolates (Scheme ) . Use of an N ‐(4‐methoxybenzyl) protecting group provided a route to the desired amino acid derivatives, through oxidative deprotection and hydrolysis of the hydantoin.…”

Section: Two‐electron Smiles Rearrangementmentioning

confidence: 99%

Modern Aspects of the Smiles Rearrangement

Holden

Greaney

2017

Chemistry A European J

172

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The Smiles rearrangement is an intramolecular S Ar reaction, breaking a C-X single bond and forming a new C-X or C-C bond though ipso substitution. Its vast scope, in terms of nucleophile, leaving group, and ring-size of the transition state, make it a powerful tool for arene functionalization, as it can be employed strategically to switch easily-forged bonds with more difficult connections that would be challenging to realize in the intermolecular mode. The reaction has received significantly renewed attention in recent years, as advances in areas such as arene C-X bond formation and radical generation have been harnessed for new arene syntheses through Smiles chemistry. In addition, new reaction modes have been discovered, such as the Clayden rearrangement of lithiated ureas, creating innovative applications for Smiles rearrangements in asymmetric arylation. This Minireview will discuss advances in these areas in the recent literature, covering both two-electron, polar Smiles rearrangements along with single-electron radical transformations.

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“…Attempts to extend the scope of this reaction prompted Clayden and coworkers to address the challenge of applying this anionic arylation to the enolates of amino acid derivatives (Scheme 32). 58 A series of natural and unnatural amino acids were derivatized as ureas, treated under optimized conditions, and quenched with dilute HCl to give racemic hydantoins. For a range of amino acid derivatives, with a variety of migrating aryl (including pyridyl) rings, arylation took place cleanly.…”

Section: Arylation Of Estersmentioning

confidence: 99%