A synthetic route toward α,α-dialkyl α-amino ester derivatives via radical addition to hydrazone derivatives of α-ketoesters under “on-water” conditions

Nam, Tae Kyu; Jang, Doo Ok

doi:10.1016/j.tetlet.2019.151411

Cited by 8 publications

(6 citation statements)

References 46 publications

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“…The corresponding products were obtained in good to excellent yields with excellent regioselectivity (only C-4-selective product, 4-49). As shown in Scheme 2, a series of primary benzyl radical precursors were identified as suitable coupling partners for this route (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). These radical precursors consisted of monosubstituted, disubstituted, trisubstituted, naphthyl, and heterocyclic RAEs with diversified functional groups.…”

Section: Resultsmentioning

confidence: 99%

“…However, those methods were applied to limited reaction types, functional groups, multi-step protocols, and toxic reagents. [3] Most recently, methodology development has utilized radical chemistry such as intramolecular radical C(sp 3 )À H aminations, [4] the addition of an open-shell species to an imine, [5] amino acid precursor coupling, [6] and using CO 2 as a carboxyl source (Scheme 1a). [7] These methods have rapid access to novel unnatural ATAA libraries containing various structural motifs.…”

Section: Introductionmentioning

confidence: 99%

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Modular Construction of Unnatural α‐Tertiary Amino Acid Derivatives by Multicomponent Radical Cross‐Couplings

Yang

Geng

et al. 2022

Angewandte Chemie

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Although the synthesis of α-tertiary amino acids (ATAAs) has been extensively studied, the development of an inexpensive and facile methodology to incorporate multifunctionality on ATAAs remains challenging. In this article, we present a single-step radical approach for the modular synthesis of functionally diverse ATAAs. This synthesis takes place under mild conditions with an absence of metals, photocatalysts, and all other additives. We demonstrate the broad applications of this approach on a variety of aliphatic and aromatic carboxylic acids, alkenes, 1,3enynes, and oxazolones. The results prove that our method provides excellent functional group tolerance and late-stage applicability, as well as gram-scale synthesis via flow chemistry. Additionally, we include mechanistic studies which reveal that the excited state of oxazolone enolate upon light excitation is a key intermediate that acts as a radical precursor and an efficient reductant.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modular Construction of Unnatural α‐Tertiary Amino Acid Derivatives by Multicomponent Radical Cross‐Couplings

Yang

Geng

et al. 2022

Angewandte Chemie

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“…An alternative metal-free method for the synthesis of quaternary a-amino esters was reported by Nam and Jang (Scheme 3B). [14] This procedure employs BEt 3 as ar adical initiator to generate open-shell species from alkyl iodides. Thegenerated radical intermediates undergo radical addition to hydrazine derivatives of a-keto esters to produce the desired products.N otably,t his transformation works better when using H 2 Oa st he solvent and under air.…”

Section: Addition To Iminesmentioning

confidence: 99%

Radical‐Based Synthesis and Modification of Amino Acids

et al. 2020

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AdriµnG ómez-Suµrez graduated from the University of Santiago de Compostela in 2009. In 2014 he was awarded his PhD from the University of St. Andrews for his studies on the chemistry of dinuclear gold complexes under the supervision of Prof. Steven P. Nolan. Forp ostdoctoral research he moved to the WWU Münster to work with Prof. Frank Glorius. In 2018 he started his habilitation at the Bergische Universität Wuppertal, under the mentorship of Prof. Stefan F. Kirsch. His research interests include radical chemistry,c atalysis, and photochemistry. Scheme 1. Syntheses of a,b-diamino esters. Scheme 2. Synthesis of C-glyco-a-AAs.

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“…Eine alternative,m etallfreie Methode zur Synthese von quartären a-Aminoestern wurde von Jang beschrieben (Ab- bildung 3B). [14] Dieser Ansatz verwendet BEt 3 als Initiator, um aus Alkyliodiden Radikale zu generieren. Die erzeugten Radikalintermediate addieren an Hydrazinderivate von a-Ketoestern, um so die gewünschten Produkte zu liefern.…”

Section: Addition An Imineunclassified