Asymmetric synthesis of α-amino acids from α,β-(Z)-didehydroamino acid derivatives with 1,2,3,6-tetrahydropyrazin-2-one structure

Abellan, Tomas; Mancheño, Balbino; Nájera, Carmén; Sansano, José M.

doi:10.1016/s0040-4020(01)00553-1

Cited by 35 publications

(23 citation statements)

References 66 publications

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“…They acted as antimicrobial and phytotoxic agents and, once incorporated in the peptidic sequence, an enhanced resistance of enzymatic and chemical degradation of the resulting proteins occurred [152]. The didehydroalanine derivative and enaminone can give DDAA derivative using Heck olefination and vinylic nucleophilic substitution.…”

Section: Reactions Of Enaminones With Organometallicsmentioning

confidence: 99%

“…The didehydroalanine derivative and enaminone can give DDAA derivative using Heck olefination and vinylic nucleophilic substitution. Enaminones 278 u n d e rwent vinylic nucleophilic substitution, acting as β-a c y l v i n y l cation by organomagnesium compounds affording diastereoselectively (Z)-DDAA derivatives 2 7 9 in moderate yields ( Figure 98) [152].…”

Section: Reactions Of Enaminones With Organometallicsmentioning

confidence: 99%

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Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Negri

Kascheres

2004

Journal of Heterocyclic Chem

177

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Enaminoketones and esters are gaining increased interest, particularly cyclic-β-enaminoesters, which are known as important intermediates for the synthesis of heterocycles and natural products, because the enantioselective preparation of highly functionalized compounds is of central importance in synthetic chemistry. Enaminones are versatile synthetic intermediates that combine the ambident nucleophilicity of enamines with the ambident eletrophilicity of enones. Enaminoketones and enaminonitriles have proven to be versatile building blocks for the synthesis of various heterocycles such as pyridine, pyrimidine and pyrrole derivatives. Enaminones systems have "enone" character, and may act as acceptors in both 1,2 and 1,4-additions. In this way the enaminone serves as a scaffold for annulation, and can gain access to systems such as pyrroles indolizidines, quinolizidines and perhydroindoles, all of which are common motifs in alkaloid structures. Enaminones are frequently employed as building blocks for the preparation of a variety of bicyclic compounds of biological interest and have been recently recognized as potential anticonvulsant compounds. Since a large number of developments in the use of enaminones in heterocyclic synthesis have occurred, a review of the recent developments in the synthetic approaches, covering the literature since 1995 until 2004, to these interesting molecules and their useful chemical transformations and biological activity can be considered of considerable value.J. Heterocyclic Chem., 41, 461 (2004).Enaminoketones. Introduction.The term enaminone was introduced by Greenhill to define the enamine of a 1,3-diketone, β-ketoester or similar 1,3-difunctional reagents, and is used to indicate any compound containing the conjugated system N-C=C-C=O [1]. Enaminones are versatile synthetic intermediates that combine the ambident nucleophilicity of enamines with the ambident eletrophilicity of enones. The chemistry of the enaminocarbonyl group 1 is potentially an area of considerable scope when one considers that there are present in this moiety, three nucleophilic sites (a, c and e) and two electrophilic sites (b and d) [2][3][4] (Figure 1).Theorically, primary and secondary acyclic enaminones can exist in three tautomeric forms: ketamino form, iminoenol form and oxoimino form [1][2][3]. There is also evidence that cyclic enaminones exist primarily in the enaminoketo form. A study of cyclic enaminoketones shows that these compounds have a significant steric fator in the six-membered ring. The six-membered ring enaminoketones are only slightly stronger bases than the saturated amines, whereas five-and-seven membered rings are much stronger bases than saturated amines. This has been attributed to a large steric strain present in six-membered enaminoketones [5].β-Aminoenones or enaminoketones can exist in four conformations owing to restricted rotations around the C=C double and C-C=O single bonds [3]. Enaminones with primary or secondary amino groups can exist in both Z-and E-forms. If there is a...

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Section: Reactions Of Enaminones With Organometallicsmentioning

confidence: 99%

Section: Reactions Of Enaminones With Organometallicsmentioning

confidence: 99%

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Negri

Kascheres

2004

Journal of Heterocyclic Chem

177

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“…The α,β-didehydroaminoacids (DDAAS) are one of the conformationally constrained noncoded aminoacids. They acted as antimicrobial and phytotoxic agents and, once incorporated in the peptidic sequence, an enhanced resistance of enzymatic and chemical degradation of the resulting proteins occurred [152]. The didehydroalanine derivative and enaminone can give DDAA derivative using Heck olefination and vinylic nucleophilic substitution.…”

Section: Reactions Of Enaminones With Organometallicsmentioning

confidence: 99%

“…The didehydroalanine derivative and enaminone can give DDAA derivative using Heck olefination and vinylic nucleophilic substitution. Enaminones 278 u n d e r-went vinylic nucleophilic substitution, acting as β-a c y l v i n y l cation by organomagnesium compounds affording diastereoselectively (Z)-DDAA derivatives 2 7 9 in moderate yields ( Figure 98) [152].…”

Section: Reactions Of Enaminones With Organometallicsmentioning

confidence: 99%

Recent Development in Preparation Reactivity and Biological Activity of Enaminoketones and Enaminothiones and Their Utilization to Prepare Heterocyclic Compounds

Negri¹,

Kascheres²,

Kascheres³

2004

ChemInform

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“…While the pioneering works in this field were based on the use of harmful radical initiators such as Et 3 B, Bu 3 SnH, and AIBN, [86][87][88][89][90][91][92][93][94][95]97,[144][145][146][147] later the chemists found that the less toxic zinc, indium and copper are also capable as reductants to generate radicals from more hard reagents. [96,97,148,151,152,[162][163][164] In the past 5 years, a new round of development in the asymmetric synthesis of non-proteinogenic AAs has been begun by photoredox chemistry.…”

Section: Methodsmentioning

confidence: 99%

Advances in Asymmetric Amino Acid Synthesis Enabled by Radical Chemistry

2020

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Chiral amino acids (AAs), being the main "building" blocks of the living organisms, are also an important class of organic compounds which broadly applied in synthetic chemistry, biochemistry, catalysis and the designing of new drugs. According to the industrial-commodity market, chiral non-proteinogenic AAs containing various functional groups come to the fore. To date, radical cross-coupling reactions are becoming an option as an attractive powerful tool for AA syntheses. Owing to mild reaction conditions and high functional-group tolerance, radical chemistry represents an ideal strategy for the synthesis of challenging complex non-proteinogenic AAs. Moreover, the radical cross-coupling allows introducing AA residue into drug scaffolds and natural compounds. In the present review, we wish to summarize and discuss all the reported to date methods of the asymmetric synthesis of AAs using radical chemistry by presenting a comprehensive account of the literature in this field going back to 1990. We especially emphasize on a radical chemistry approach and, exclusively, on stereoselective synthesis of various α-, β-, γ-AAs and derivatives employing a different type of radical initiators starting from AIBN and organostannes and ending with powerful photoredox catalysis. Furthermore, the mechanism of the reported reactions will be discussed. Radicals Generated from AA Derivatives in Conjugate Additions 6.1. Radicals Generated from α-Substituted Glycine Derivatives in AA Synthesis 6.2. Modification of Chiral AA Side Chain by Radical Chemistry 7.

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Asymmetric synthesis of α-amino acids from α,β-(Z)-didehydroamino acid derivatives with 1,2,3,6-tetrahydropyrazin-2-one structure

Cited by 35 publications

References 66 publications

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Recent Development in Preparation Reactivity and Biological Activity of Enaminoketones and Enaminothiones and Their Utilization to Prepare Heterocyclic Compounds

Advances in Asymmetric Amino Acid Synthesis Enabled by Radical Chemistry

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