Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Long-range diastereoselectivity in Ugi reactions of 2-substituted dihydrobenzoxazepines.

ABSTRACT: The Ugi reaction of 2-substituted dihydrobenzoxazepines was found to proceed with unexpectedly good diastereoselectivitiy (diastereoisomeric ratios up to 9:1), despite the large distance between the pre-existing stereogenic centre and the newly generated one. This result represents the first good 1,4 asymmetric induction in an Ugi reaction as well as the first example of diastereoselective Ugi reaction of seven membered cyclic imines. It allows the diversity-oriented synthesis of various tetrahydro[f][1,4]benzoxazepines.

SUBMITTER: Banfi L

PROVIDER: S-EPMC3170203 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Long-range diastereoselectivity in Ugi reactions of 2-substituted dihydrobenzoxazepines.

Banfi Luca L Basso Andrea A Cerulli Valentina V Rocca Valeria V Riva Renata R

Beilstein journal of organic chemistry 20110713

The Ugi reaction of 2-substituted dihydrobenzoxazepines was found to proceed with unexpectedly good diastereoselectivitiy (diastereoisomeric ratios up to 9:1), despite the large distance between the pre-existing stereogenic centre and the newly generated one. This result represents the first good 1,4 asymmetric induction in an Ugi reaction as well as the first example of diastereoselective Ugi reaction of seven membered cyclic imines. It allows the diversity-oriented synthesis of various tetrahy ...[more]

PMID: 21915196

Similar Datasets

Diverse Isoquinoline Scaffolds by Ugi/Pomeranz-Fritsch and Ugi/Schlittler-Muller Reactions.

Project description:The Pomeranz-Fritsch reaction and its Schlittler-Müller modification were successfully applied in the Ugi postcyclization strategy by using orthogonally protected aminoacetaldehyde diethyl acetal and complementary electron rich building blocks. Several scaffolds, including isoquinolines, carboline, alkaloid-like tetrazole-fused tetracyclic compounds, and benzo[ d]azepinone scaffolds, were synthesized in generally moderate to good yield. All our syntheses provide a short MCR-based sequence to novel or otherwise difficult to access scaffolds. Hence, we foresee multiple applications of these synthesis technologies.

| S-EPMC6528277 | biostudies-literature

The Catalytic Enantioselective Ugi Four-Component Reactions.

Project description:Finally stereoselective: Enantioselective variations have been developed for many multicomponent reactions; however, it has been missing for the Ugi four-component reaction. This has now changed with the discovery of an efficient catalytic enantioselective variant for the four-component reaction of isocyanides, primary amines, aldehydes or ketones, and carboxylic acids.

| S-EPMC6346735 | biostudies-literature

Raising the Diversity of Ugi Reactions Through Selective Alkylations and Allylations of Ugi Adducts.

Project description:We report here selective Tsuji-Trost type allylation of Ugi adducts using a strategy based on the enhanced nucleophilicity of amide dianions. Ugi adducts derived from aromatic aldehydes were easily allylated at their peptidyl position with allyl acetate in the presence of palladium catalysts. These substitutions were compared to more classical transition metal free allylations using allyl bromides.

| S-EPMC6361783 | biostudies-literature

Remote control of diastereoselectivity in intramolecular reactions of chiral allylsilanes.

Project description:During investigations of cyclization reactions between chiral allylsilanes and N-acyliminium ions, it was discovered that a suitably positioned benzyloxy group on the allylsilane component caused a reversal in the diastereoselectivity of these reactions relative to that normally observed with alkyl-substituted allylsilanes. This effect was subsequently observed in two other reaction types. Investigations into this effect led to the proposal of product formation through thermodynamic control facilitated by neighboring group interactions with a transient cationic species. This hypothesis was experimentally supported by the isolation of an intermediate in the proposed mechanistic pathway.

| S-EPMC2519900 | biostudies-literature

Solid-phase synthesis of N-substituted pyrrolidinone-tethered N-substituted piperidines via Ugi reaction.

Project description:Starting with resin-bound glutamic acid, an efficient synthesis of N-substituted pyrrolidinones is described, using the Ugi four-component reaction (U-4CR). The same methodology is employed to produce N-substituted pyrrolidinone tethered N-substituted piperidines.

| S-EPMC2917892 | biostudies-literature

Insights into Synergistic Effects of Counterion and Ligand on Diastereoselectivity Switch in Gold-Catalyzed Post-Ugi Ipso-Cyclization.

Project description:The concept of diastereoselectivity switch in gold catalysis is investigated, which primarily depends on the effects of ligand and counterion. The origins of gold-catalyzed post-Ugi ipso-cyclization for the diastereoselective synthesis of spirocyclic pyrrol-2-one-dienone have been explored with density functional theory calculations. The reported mechanism emphasized the importance of the cooperation of ligand and counterion in diastereoselectivity switch, leading to the stereocontrolling transition states. Furthermore, the nonbonding interactions primarily between the catalyst and the substrate play a significant role in the cooperation of ligand and counterion. This work would be useful to further understand the reaction mechanism of gold-catalyzed cyclization and the effects of ligand and counterion.

| S-EPMC10308395 | biostudies-literature

Origin of the Diastereoselectivity of the Heterogeneous Hydrogenation of a Substituted Indolizine.

Project description:In this work, the stereoselective heterogeneous hydrogenation of a tetrasubstituted indolizine was studied. Partial hydrogenation products were obtained in three steps from a substituted pyridine-2-carboxaldehyde prepared from commercial pyridoxine hydrochloride. The hydrogenation of the indolizine ring was shown to be diastereoselective, forming trans-6b and cis-9. Theoretical calculations (ab initio and DFT) were used to rationalize the unusual trans stereoselectivity for 6b, and a keto-enol tautomerism under kinetic control has been proposed as the source of diastereoselectivity.

| S-EPMC7498159 | biostudies-literature

Diastereoselectivity in Lewis-acid-catalyzed Mukaiyama aldol reactions: a DFT study.

Project description:The basis for diastereoselectivity in Lewis-acid-catalyzed Mukaiyama aldol reactions was studied using density functional theory. By exploring the conformations of the transition structures for the diastereodifferentiating step of seven different reactions, simple models were generated. The effects of varying the substituents on the enol carbon and the ?-carbon of the silyl enol ether from methyl to tert-butyl groups and the substituent on the aldehyde from methyl to phenyl groups were investigated by comparison of the transition structures for different reactions. Expanding on the previous qualitative models by Heathcock and Denmark, we found that while the pro-anti pathways take place via antiperiplanar transition structures, the pro-syn pathways prefer synclinal transition structures. The relative steric effects of the Lewis acid and trimethyl silyl groups and the influence of E/Z isomerism on the aldol transition state were investigated. By calculating 36 transition structures at the M06/6-311G*//B3LYP/6-31G* level of theory and employing the IEFPCM polarizable continuum model for solvation effects, this study expands the mechanistic knowledge and provides a model for understanding the diastereoselectivity in Lewis-acid-catalyzed Mukaiyama aldol reactions.

| S-EPMC3465709 | biostudies-literature

Synthesis of acylhydrazino-peptomers, a new class of peptidomimetics, by consecutive Ugi and hydrazino-Ugi reactions.

Project description:Herein we describe a versatile approach for the synthesis of acylhydrazino-peptomers, a new class of peptidomimetics. The key idea in this approach is based on a simple route using a one-pot hydrazino-Ugi four-component reaction followed by a hydrazinolysis or hydrolysis reaction and subsequent hydrazino-Ugi reaction or classical Ugi reaction for the construction of acyclic acylhydrazino-peptomers. The consecutive multicomponent reactions produced a variety of acylhydrazino-peptomers in moderate to excellent yields (47-90%). These compounds are multifunctional intermediates that can be further functionalized to obtain new peptidomimetics with potential biological activity.

| S-EPMC5238544 | biostudies-literature

Iridium-catalyzed reductive Ugi-type reactions of tertiary amides.

Project description:Amides are ubiquitous in the fine chemical, agrochemical and pharmaceutical industries, but are rarely exploited as substrates for homologous amine synthesis. By virtue of their high chemical stability, they are essentially inert to all but the harshest of chemical reagents and to the majority of chemical transformations routinely used in organic synthesis. Accordingly, the development of chemoselective carbon-carbon bond-forming methodologies arising from the functionalization of the amide functionality should find widespread use across academia and industry. We herein present our findings on a series of Ugi-type reactions of tertiary amides enabled by an initial chemoselective iridium-catalyzed partial reduction, followed by reaction with isocyanide and (thio)acetic acid or trimethylsilyl azide, thus providing a multicomponent synthesis of α-amino (thio)amide or α-amino tetrazole derivatives. The reductive Ugi-type reactions are amenable to a broad range of amides and isocyanides, and are applicable to late-stage functionalization of various bioactive molecules and pharmaceutical compounds.

| S-EPMC6053461 | 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