Browse
Submit Data
Databases
API
Help

Dataset Information

28 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

One-pot synthesis of novel chiral ?-amino acid derivatives by enantioselective Mannich reactions catalyzed by squaramide cinchona alkaloids.

ABSTRACT: An ef?cient one-pot synthesis of novel ?-amino acid derivatives containing a thiadiazole moiety was developed using a chiral squaramide cinchona alkaloid as organocatalyst. The reactions afforded chiral ?-amino acid derivatives in moderate yields and with moderate to excellent enantioselectivities. The present study demonstrated for the first time the use of a Mannich reaction catalyzed by a chiral bifunctional organocatalyst for the one-pot synthesis of novel ?-amino acid derivatives bearing a 1,3,4-thiadiazole moiety on nitrogen.

SUBMITTER: Zhang K

PROVIDER: S-EPMC6270396 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

One-pot synthesis of novel chiral β-amino acid derivatives by enantioselective Mannich reactions catalyzed by squaramide cinchona alkaloids.

Zhang Kankan K Liang Xueping X He Ming M Wu Jian J Zhang Yuping Y Xue Wei W Jin Linhong L Yang Song S Hu Deyu D

Molecules (Basel, Switzerland) 20130523 6

An efﬁcient one-pot synthesis of novel β-amino acid derivatives containing a thiadiazole moiety was developed using a chiral squaramide cinchona alkaloid as organocatalyst. The reactions afforded chiral β-amino acid derivatives in moderate yields and with moderate to excellent enantioselectivities. The present study demonstrated for the first time the use of a Mannich reaction catalyzed by a chiral bifunctional organocatalyst for the one-pot synthesis of novel β-amino acid derivatives bearing a ...[more]

PMID: 23702920

Similar Datasets

The Mannich reaction of malonates with simple imines catalyzed by bifunctional cinchona alkaloids: enantioselective synthesis of beta-amino acids.

Project description:We describe the first efficient, direct asymmetric Mannich reactions with malonates and N-Boc aryl and alkyl imines by cooperative hydrogen-bonding catalysis with a cinchona alkaloid bearing a thiourea functionality. We have also extended the scope of this reaction to beta-ketoesters. The synthetic value of this new reaction is demonstrated in the establishment of a convergent enantioselective route toward the biologically important beta-amino acids under mild and air- and moisture-tolerant conditions.

| S-EPMC3172002 | biostudies-literature

Enantioselective nitroaldol reaction of alpha-ketoesters catalyzed by cinchona alkaloids.

Project description:The development of highly enantioselective and general catalytic nitroaldol (Henry) reactions with ketones is a challenging yet desirable task in organic synthesis. In this communication, we report an asymmetric nitroaldol reaction with alpha-ketoesters catalyzed by a new C6'-OH cinchona alkaloid catalyst. This is the first highly efficient organocatalytic asymmetric Henry reaction with ketones. This reaction is operationally simple and affords high enantioselectivity as well as good to excellent yield for a broad range of alpha-ketoesters.

| S-EPMC3161415 | biostudies-literature

Enantioselective direct Mannich-type reactions of 2-benzylpyridine N-oxides catalyzed by chiral bis(guanidino)iminophosphorane organosuperbase.

Project description:2-Benzylpyridine N-oxides possessing less acidic α-protons were utilized as pronucleophiles for the first time in enantioselective addition reactions under Brønsted base catalysis. A chiral bis(guanidino)iminophosphorane was able to overcome the inherent issue of low acidity of the pronucleophiles, establishing the diastereo- and enantioselective direct Mannich-type reaction with N-Boc imines. The control experiments indicated that the N-oxide moiety of the substrates played a critical role in achieving the high stereoselectivity.

| S-EPMC5944382 | biostudies-literature

N-heterocyclic carbene-catalyzed enantioselective Mannich reactions with alpha-aryloxyacetaldehydes.

Project description:N-Heterocyclic carbenes (NHCs) catalyze a new Mannich-type reaction to form beta-amino acid derivatives in high yield and enantioselectivity. The reaction is initiated by the addition of an NHC to an alpha-aryloxyaldehyde followed by elimination of a phenoxide anion which generates an enol/enolate. A Mannich addition to a tosylimine proceeds with excellent control over enantioselectivity. In a new carbene catalysis concept, catalyst regeneration is promoted by return, or rebound, and acylation of the phenoxide group which served as the activating component in the first step of the catalytic cycle. The activated ester products formed in situ are manipulated to form a variety of useful compounds including beta-amino acids, beta-amino amides, and peptides.

| S-EPMC2836487 | biostudies-literature

Asymmetric Petasis Borono-Mannich Allylation Reactions Catalyzed by Chiral Biphenols.

Project description:Chiral biphenols catalyze the asymmetric Petasis borono-Mannich allylation of aldehydes and amines through the use of a bench-stable allyldioxaborolane. The reaction proceeds via a two-step, one-pot process and requires 2-8 mole % of 3,3'-Ph2 -BINOL as the optimal catalyst. Under microwave heating the reaction affords chiral homoallylic amines in excellent yields (up to 99 %) and high enantioselectivies (er up to 99:1). The catalytic reaction is a true multicomponent condensation reaction whereas both the aldehyde and the amine can possess a wide range of structural and electronic properties. Use of crotyldioxaborolane in the reaction results in stereodivergent products with anti- and syn-diastereomers both in good diastereoselectivities and enantioselectivities from the corresponding E- and Z-borolane stereoisomers.

| S-EPMC5716625 | biostudies-literature

New ?- and ?-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions.

Project description:The preparation of new organocatalysts for asymmetric syntheses has become a key stage of enantioselective catalysis. In particular, the development of new cyclodextrin (CD)-based organocatalysts allowed to perform enantioselective reactions in water and to recycle catalysts. However, only a limited number of organocatalytic moieties and functional groups have been attached to CD scaffolds so far. Cinchona alkaloids are commonly used to catalyze a wide range of enantioselective reactions. Thus, in this study, we report the preparation of new ?- and ?-CD derivatives monosubstituted with cinchona alkaloids (cinchonine, cinchonidine, quinine and quinidine) on the primary rim through a CuAAC click reaction. Subsequently, permethylated analogs of these cinchona alkaloid-CD derivatives also were synthesized and the catalytic activity of all derivatives was evaluated in several enantioselective reactions, specifically in the asymmetric allylic amination (AAA), which showed a promising enantiomeric excess of up to 75% ee. Furthermore, a new disubstituted ?-CD catalyst was prepared as a pure AD regioisomer and also tested in the AAA. Our results indicate that (i) the cinchona alkaloid moiety can be successfully attached to CD scaffolds through a CuAAC reaction, (ii) the permethylated cinchona alkaloid-CD catalysts showed better results than the non-methylated CDs analogues in the AAA reaction, (iii) promising enantiomeric excesses are achieved, and (iv) the disubstituted CD derivatives performed similarly to monosubstituted CDs. Therefore, these new CD derivatives with cinchona alkaloids effectively catalyze asymmetric allylic aminations and have the potential to be successfully applied in other enantioselective reactions.

| S-EPMC6466772 | biostudies-literature

Organocatalytic Enantioselective γ-Position-Selective Mannich Reactions of β-Ketocarbonyl Derivatives.

Project description:Catalytic asymmetric Mannich reactions of β-ketocarbonyl derivatives (such as β-ketoesters and (2-oxopropyl)phosphonate), resulting in the formation of a C-C bond at the γ-position of the β-ketocarbonyl derivatives with high enantioselectivities, are reported. The bond formation at the α-position of the β-ketoester was reversible, and the γ-position-reacted product δ-amino β-ketoester derivative was kinetically formed and was stable. The dynamic kinetic process was key for the direct access to the γ-position-reacted products from β-ketocarbonyls under catalytic conditions.

| S-EPMC9513800 | biostudies-literature

Enantioselective one-pot synthesis of 4<i>H</i>-chromene derivatives catalyzed by a chiral Ni(ii) complex.

Project description:A Ni(ii)-bis(oxazoline) complex and p-TSOH are used to form enantioenriched 4H-chromenes from ortho-quinone methides (o-QMs) and dicarbonyls, providing the desired products in up to 95% ee. The method is compatible with various β-ketoester substrates, and the products obtained could be converted into biologically active 4H-chromene derivatives.

| S-EPMC9058437 | biostudies-literature

Cyclopropenimine-catalyzed enantioselective Mannich reactions of tert-butyl glycinates with N-Boc-imines.

Project description:Cyclopropenimine 1 is shown to catalyze Mannich reactions between glycine imines and N-Boc-aldimines with high levels of enantio- and diastereocontrol. The reactivity of 1 is shown to be substantially greater than that of a widely used thiourea cinchona alkaloid-derived catalyst. A variety of aryl and aliphatic N-Boc-aldimines are effective substrates for this transformation. A preparative-scale reaction to deliver >90 mmol of product is shown using 1 mol % catalyst. The products of this transformation can be converted into several useful derivatives.

| S-EPMC3804837 | biostudies-literature

Chiral phosphoramide-catalyzed, enantioselective, directed cross-aldol reactions of aldehydes.

Project description:Catalytic, enantioselective, directed cross-aldol reactions of aldehydes are described. The addition of isobutyraldehyde trichlorosilyl enolate 2 to various aldehydes in the presence of 10 mol % bisphosphoramide 4 provides aldol products in high yields with moderate to good enantioselectivities. The reaction works well with a wide range of aromatic, olefinic, and aliphatic aldehydes. Enantioselectivities are highly dependent on the electronic nature of the aldehyde substituent. Hammett studies reveal that enantioselectivity increases as aldehydes become either more electron rich or more electron poor.

| S-EPMC397401 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data