Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Organocatalytic Enantioselective α-Bromination of Aldehydes with N-Bromosuccinimide.

ABSTRACT: Despite the wealth of existing organocatalytic, enantioselective transformations, the α-bromination of aldehydes remains a challenging reaction. The four examples reported to date require expensive, inconvenient brominating agents to achieve the desired products in excellent yields and enantioselectivities. The preferred brominating agent, N-bromosuccinimide (NBS), has been repeatedly discarded for these reactions because it results in low yields and relatively poor enantioselectivities. We describe a methodology that uses NBS and performs excellently with low catalyst loadings, short reaction times, and mild temperatures.

SUBMITTER: Hutchinson G

PROVIDER: S-EPMC9207931 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Organocatalytic Enantioselective α-Bromination of Aldehydes with <i>N</i>-Bromosuccinimide.

Hutchinson George G Alamillo-Ferrer Carla C Fernández-Pascual Martín M Burés Jordi J

The Journal of organic chemistry 20220526 12

Despite the wealth of existing organocatalytic, enantioselective transformations, the α-bromination of aldehydes remains a challenging reaction. The four examples reported to date require expensive, inconvenient brominating agents to achieve the desired products in excellent yields and enantioselectivities. The preferred brominating agent, <i>N</i>-bromosuccinimide (NBS), has been repeatedly discarded for these reactions because it results in low yields and relatively poor enantioselectivities. ...[more]

PMID: 35617931

Similar Datasets

Organocatalytic Enantioselective α-Nitrogenation of α,α-Disubstituted Aldehydes in the Absence of a Solvent.

Project description:A highly efficient enantioselective α-nitrogenation method of α,α-disubstituted aldehydes with azodicarboxylates promoted by a chiral carbamate-monoprotected cyclohexa-1,2-diamine as organocatalyst has been developed. The process was carried out without any solvent, and the corresponding α,α-disubstituted α-nitrogenated aldehydes were obtained with excellent yields and enantioselectivities up to 99% ee. The sustainability of the procedure was established through the calculation of green metrics, such as EcoScale and E-factor. In addition, theoretical calculations have been used to justify the obtained enantioselectivity sense.

| S-EPMC9639010 | biostudies-literature

Development of a general, enantioselective organocatalytic Mukaiyama-Michael reaction with α,β-unsaturated aldehydes.

Project description:LUMO-lowering organocatalysis has been extended to promote the conjugate addition of S-alkyl and -pyrrolyl silylketene acetals to α,β-unsaturated aldehydes, yielding both, syn and anti Mukaiyama-Michael products with high levels of enantioselectivity. This strategy allows for the generation of chemically useful 1,5-dicarbonyl systems and again highlights the utility of organocatalysis.

| S-EPMC4158731 | biostudies-literature

Substrate Directed Regioselective Monobromination of Aralkyl Ketones Using N-Bromosuccinimide Catalysed by Active Aluminium Oxide: α -Bromination versus Ring Bromination.

Project description:Bromination of aralkyl ketones using N-bromosuccinimide in presence of active Al2O3 provided either α -monobrominated products in methanol at reflux or mononuclear brominated products in acetonitrile at reflux temperature with excellent isolated yields depending on the nature of substrate employed. The α -bromination was an exclusive process when aralkyl ketones containing moderate activating/deactivating groups were subjected to bromination under acidic Al2O3 conditions in methanol at reflux while nuclear functionalization was predominant when aralkyl ketones containing high activating groups were utilized for bromination in presence of neutral Al2O3 conditions in acetonitrile at reflux temperature. In addition, easy isolation of products, use of inexpensive catalyst, short reaction time (10-20 min), and safe operational practice are the major benefits in the present protocol.

| S-EPMC4041026 | biostudies-literature

Organocatalytic enantioselective synthesis of alpha-hydroxy phosphonates.

Project description:Tertiary alpha-hydroxy phosphonates have been synthesized in good yields and high enantiomeric purity (up to 99% ee) through a novel l-proline-catalyzed cross aldol reaction of alpha-keto phosphonates and ketones.

| S-EPMC2535926 | biostudies-literature

Enantioselective organocatalytic α-fluorination of cyclic ketones.

Project description:The first highly enantioselective α-fluorination of ketones using organocatalysis has been accomplished. The long-standing problem of enantioselective ketone α-fluorination via enamine activation has been overcome via high-throughput evaluation of a new library of amine catalysts. The optimal system, a primary amine functionalized Cinchona alkaloid, allows the direct and asymmetric α-fluorination of a variety of carbo- and heterocyclic substrates. Furthermore, this protocol also provides diastereo-, regio-, and chemoselective catalyst control in fluorinations involving complex carbonyl systems.

| S-EPMC3107934 | biostudies-literature

Organocatalytic highly enantioselective synthesis of secondary alpha-hydroxyphosphonates.

Project description:[reaction: see text] The first organocatalytic cross aldol reaction of ketones and diethyl formylphosphonate hydrate has been realized by using readily available l-prolinamide as the catalyst. Secondary alpha-hydroxyphosphonates have been synthesized in high enantioselective (up to >99% ee) and good diastereoselectivity.

| S-EPMC2525621 | biostudies-literature

Enantioselective organocatalytic Michael addition of aldehydes to nitroethylene: efficient access to gamma2-amino acids.

Project description:Enantioselective organocatalytic Michael addition of aldehydes to nitroethylene catalyzed by (S)-diphenylprolinol silyl ether provides beta-substituted-delta-nitroalcohols in nearly optically pure form (96-99% ee). The Michael adducts bear a single substituent adjacent to the carbonyl and can be efficiently converted to protected gamma2-amino acids, which are essential for the systematic conformational studies of gamma-peptide foldamers.

| S-EPMC3429127 | biostudies-literature

Organocatalytic enantioselective synthesis of both diastereomers of alpha-hydroxyphosphinates.

Project description:Racemic alpha-acylphosphinates and formylphosphinate hydrate were used directly as the substrates in a proline derivative-catalyzed cross aldol reaction with ketones. Because of the preexisting phosphorus stereogenic center, a mixture of two diastereomers of the corresponding alpha-hydroxyphosphinates was obtained in this reaction. Good to high enantioselectivities (up to 99% ee) were obtained simultaneously for the two diastereomers in good yields. Good diastereoselectivities were also obtained when the reaction generates an additional carbon stereogenic center.

| S-EPMC2821456 | biostudies-literature

Organocatalytic High Enantioselective Synthesis of β-Formyl-α-hydroxyphosphonates.

Project description:The cross aldol reaction between enolizable aldehydes and α-ketophosphonates was achieved for the first time by using 9-amino-9-deoxy-epi-quinine as the catalyst. β-Formyl-α-hydroxyphosphonates were obtained in high to excellent enantioselectivities. The reaction works especially well with acetaldehyde, which is a tough substrate for organocatalyzed cross aldol reactions. The products were demonstrated to have anticancer activities.

| S-EPMC3170695 | biostudies-literature

Organocatalytic cascade aza-Michael/hemiacetal reaction between disubstituted hydrazines and α,β-unsaturated aldehydes: Highly diastereo- and enantioselective synthesis of pyrazolidine derivatives.

Project description:The catalytic synthesis of nitrogen-containing heterocycles is of great importance to medicinal and synthetic chemists, and also a challenge for modern chemical methodology. In this paper, we report the synthesis of pyrazolidine derivatives through a domino aza-Michael/hemiacetal sequence with chiral or achiral secondary amines as organocatalysts. Thus, a series of achiral pyrazolidine derivatives were obtained with good yields (up to 90%) and high diastereoselectivities (>20:1) with pyrrolidine as an organocatalyst, and enantioenriched pyrazolidines are also achieved with good results (up to 86% yield, >10/1 regioselectivity, >20:1 dr, 99% ee) in the presence of (S)-diphenylprolinol trimethylsilyl ether catalyst.

| S-EPMC3511004 | 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