Preparation of enantiomerically pure pyridyl amino acids from serine

Tabanella, Stefania; Valancogne, Ingrid; Jackson, Richard F. W.

doi:10.1039/b308750f

Cited by 40 publications

(36 citation statements)

References 39 publications

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“…[1][2][3][4][5] Despite the frequent use of DMAP itself and the recent development of chiral DMAP derivatives for applications in stereoselective catalysis, [6][7][8][9][10][11][12][13] the mechanisms of even the most simple DMAP-catalyzed reactions, such as the acetylation of alcohols with acetic anhydride, have not yet been studied in detail. A recent review of the mechanistic characteristics of this reaction highlighted the importance of the deprotonation step as well as the influence of the auxiliary base on the catalytic activity of DMAP.…”

Section: Introductionmentioning

confidence: 99%

The DMAP‐Catalyzed Acetylation of Alcohols—A Mechanistic Study (DMAP=4‐(Dimethylamino)pyridine)

Held

Kempf

et al. 2005

Chemistry A European J

283

178

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The acetylation of tert-butanol with acetic anhydride catalyzed by 4-(dimethylamino)pyridine (DMAP) has been studied at the Becke3 LYP/6-311 + G(d,p)//Becke3 LYP/6-31G(d) level of theory. Solvent effects have been estimated through single-point calculations with the PCM/UAHF solvation model. The energetically most favorable pathway proceeds through nucleophilic attack of DMAP at the anhydride carbonyl group and subsequent formation of the corresponding acetylpyridinium/acetate ion pair. Reaction of this ion pair with the alcohol substrate yields the final product, tert-butylacetate. The competing base-catalyzed reaction pathway can either proceed in a concerted or in a stepwise manner. In both cases the reaction barrier far exceeds that of the nucleophilic catalysis mechanism. The reaction mechanism has also been studied experimentally in dichloromethane through analysis of the reaction kinetics for the acetylation of cyclohexanol with acetic anhydride, in the presence of DMAP as catalyst and triethylamine as the auxiliary base. The reaction is found to be first-order with respect to acetic anhydride, cyclohexanol, and DMAP, and zero-order with respect to triethyl amine. Both the theoretical as well as the experimental studies strongly support the nucleophilic catalysis pathway.

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Section: Introductionmentioning

confidence: 99%

The DMAP‐Catalyzed Acetylation of Alcohols—A Mechanistic Study (DMAP=4‐(Dimethylamino)pyridine)

Held

Kempf

et al. 2005

Chemistry A European J

283

178

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“…7a,c,d Several other chiral DMAP catalysts based on variations of the C(4)-N substituent have also been disclosed. 7b, [8][9][10] With the goal of developing shorter routes to potentially selective catalysts, we chose to study a new class of chiral C(3) substituted pyridine derivatives 1 (Figure 1). Placing the substitution at C(3) puts it as close to the nucleophilic pyridine nitrogen as possible without hindering the catalytically active site.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective TADMAP-Catalyzed Carboxyl Migration Reactions for the Synthesis of Stereogenic Quaternary Carbon

et al. 2005

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The chiral, nucleophilic catalyst TADMAP (1) has been prepared from 3-lithio-4-dimethylaminopyridine (5) and triphenylacetaldehyde (3), followed by acylation and resolution. TADMAP catalyzes the carboxyl migration of oxazolyl, furanyl, and benzofuranyl enol carbonates with good to excellent levels of enantioselection. The oxazole reactions are especially efficient, and are used to prepare chiral lactams (23) and lactones (30) containing a quaternary asymmetric carbon. TADMAP-catalyzed carboxyl migrations in the indole series are relatively slow and proceed with inconsistent enantioselectivity. Modeling studies (B3LYP/6-31G*) have been used in qualitative correlations of catalyst conformation, reactivity, and enantioselectivity.

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“…The spectral data of 12 were identical to the literature. 35 The purity was confirmed by 1 H NMR. N-(9-Fluorenylmethoxycarbonyl)-Se-(p-methoxybenzyl)-L-selenocysteine methyl ester (13).…”

Section: H Nmr N-(9-fluorenylmethoxycarbonyl)-o-(p-toluenesulfonyl)-mentioning

confidence: 95%

Improved synthetic routes to the selenocysteine derivatives useful for Boc-based peptide synthesis with benzylic protection on the selenium atom

Shimodaira¹,

Iwaoka²

2016

Arkivoc

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Selenocysteine (Sec) derivatives, i.e., Boc-Sec(MBn)-OH (1) and Boc-Sec(MPM)-OH (2), which are useful for chemical synthesis of selenopeptides, were obtained from L-serine in five steps with total yields of 73% and 74%, respectively. The enantiomeric excesses were confirmed to be >99% e.e. by optical resolution using a chiral column on HPLC. On the other hand, for the case of a Fmoc-protected Sec derivative, i.e., FmocSec(MPM)-OH, similar reactions resulted in low yields and partial racemization taking place.

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Preparation of enantiomerically pure pyridyl amino acids from serine

Cited by 40 publications

References 39 publications

The DMAP‐Catalyzed Acetylation of Alcohols—A Mechanistic Study (DMAP=4‐(Dimethylamino)pyridine)

The DMAP‐Catalyzed Acetylation of Alcohols—A Mechanistic Study (DMAP=4‐(Dimethylamino)pyridine)

Enantioselective TADMAP-Catalyzed Carboxyl Migration Reactions for the Synthesis of Stereogenic Quaternary Carbon

Improved synthetic routes to the selenocysteine derivatives useful for Boc-based peptide synthesis with benzylic protection on the selenium atom

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