Browse
Submit Data
Databases
API
Help

Dataset Information

32 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Direct β-alkylation of aldehydes via photoredox organocatalysis.

ABSTRACT: Direct β-alkylation of saturated aldehydes has been accomplished by synergistically combining photoredox catalysis and organocatalysis. Photon-induced enamine oxidation provides an activated β-enaminyl radical intermediate, which readily combines with a wide range of Michael acceptors to produce β-alkyl aldehydes in a highly efficient manner. Furthermore, this redox-neutral, atom-economical C-H functionalization protocol can be achieved both inter- and intramolecularly. Mechanistic studies by various spectroscopic methods suggest that a reductive quenching pathway is operable.

SUBMITTER: Terrett JA

PROVIDER: S-EPMC4333594 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Enantioselective ?-benzylation of aldehydes via photoredox organocatalysis.

Project description:The first enantioselective aldehyde ?-benzylation using electron-deficient aryl and heteroaryl substrates has been accomplished. The productive merger of a chiral imidazolidinone organocatalyst and a commercially available iridium photoredox catalyst in the presence of household fluorescent light directly affords the desired homobenzylic stereogenicity in good to excellent yield and enantioselectivity. The utility of this methodology has been demonstrated via rapid access to an enantioenriched drug target for angiogenesis suppression.

| S-EPMC3056320 | biostudies-literature

Enantioselective α-Alkylation of Aldehydes by Photoredox Organocatalysis: Rapid Access to Pharmacophore Fragments from β-Cyanoaldehydes.

Project description:The combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective α-cyanoalkylation of aldehydes. This synergistic catalysis protocol allows for the coupling of two highly versatile yet orthogonal functionalities, allowing rapid diversification of the oxonitrile products to a wide array of medicinally relevant derivatives and heterocycles. This methodology has also been applied to the total synthesis of the lignan natural product (-)-bursehernin.

| S-EPMC4548807 | biostudies-literature

Enantioselective alpha-trifluoromethylation of aldehydes via photoredox organocatalysis.

Project description:The first enantioselective, organocatalytic alpha-trifluoromethylation and alpha-perfluoroalkylation of aldehydes have been accomplished using a readily available iridium photocatalyst and a chiral imidazolidinone catalyst. A range of alpha-trifluoromethyl and alpha-perfluoroalkyl aldehydes were obtained from commercially available perfluoroalkyl halides with high efficiency and enantioselectivity. The resulting alpha-trifluoromethyl aldehydes were subsequently shown to be versatile precursors for the construction of a variety of enantioenriched trifluoromethylated building blocks.

| S-EPMC3310169 | biostudies-literature

Photoredox activation for the direct β-arylation of ketones and aldehydes.

Project description:The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a broad range of carbonyl β-functionalization reactions and is amenable to enantioselective catalysis.

| S-EPMC3723331 | biostudies-literature

Direct ?-functionalization of cyclic ketones with aryl ketones via the merger of photoredox and organocatalysis.

Project description:The direct ?-coupling of cyclic ketones with aryl ketones has been achieved via the synergistic combination of photoredox catalysis and organocatalysis. Diaryl oxymethyl or aryl-alkyl oxymethyl radicals, transiently generated via single-electron reduction of ketone precursors, readily merge with ?-enaminyl radical species, generated by photon-induced enamine oxidation, to produce ?-hydroxyketone adducts. Experimental evidence indicates that two discrete reaction pathways can be operable in this process depending upon the nature of the ketyl radical precursor and the photocatalyst.

| S-EPMC3934322 | biostudies-literature

Enantioselective aerobic oxidative cross-dehydrogenative coupling of glycine derivatives with ketones and aldehydes <i>via</i> cooperative photoredox catalysis and organocatalysis.

Project description:The combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective aerobic oxidative cross-dehydrogenative coupling between glycine derivatives and simple ketones or aldehydes, which provides an efficient approach for the rapid synthesis of enantiopure unnatural α-alkyl α-amino acid derivatives in good yield with excellent diastereo- (up to >99 : 1) and enantioselectivities (up to 97% ee). This process includes the direct photoinduced oxidation of glycine derivatives to an imine intermediate, followed by the asymmetric Mannich-type reaction with an enamine intermediate generated in situ from a ketone or aldehyde and a chiral secondary amine organocatalyst. This mild method allows the direct formation of a C-C bond with simultaneous installation of two new stereocenters without wasteful removal of functional groups.

| S-EPMC8159221 | biostudies-literature

Direct, enantioselective α-alkylation of aldehydes using simple olefins.

Project description:Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes-photoredox, enamine and hydrogen-atom transfer (HAT) catalysis-enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra- and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons.

| S-EPMC5665178 | biostudies-literature

Prebiotically Plausible Organocatalysts Enabling a Selective Photoredox α-Alkylation of Aldehydes on the Early Earth.

Project description:Organocatalysis is a powerful approach to extend and (enantio-) selectively modify molecular structures. Adapting this concept to the Early Earth scenario offers a promising solution to explain their evolution into a complex homochiral world. Herein, we present a class of imidazolidine-4-thione organocatalysts, easily accessible from simple molecules available on an Early Earth under highly plausible prebiotic reaction conditions. These imidazolidine-4-thiones are readily formed from mixtures of aldehydes or ketones in presence of ammonia, cyanides and hydrogen sulfide in high selectivity and distinct preference for individual compounds of the resulting catalyst library. These organocatalysts enable the enantioselective α-alkylation of aldehydes under prebiotic conditions and show activities that correlate with the selectivity of their formation. Furthermore, the crystallization of single catalysts as conglomerates opens the pathway for symmetry breaking.

| S-EPMC7496864 | biostudies-literature

Enantioselective direct α-amination of aldehydes via a photoredox mechanism: a strategy for asymmetric amine fragment coupling.

Project description:The direct, asymmetric α-amination of aldehydes has been accomplished via a combination of photoredox and organocatalysis. Photon-generated N-centered radicals undergo enantioselective α-addition to catalytically formed chiral enamines to directly produce stable α-amino aldehyde adducts bearing synthetically useful amine substitution patterns. Incorporation of a photolabile group on the amine precursor obviates the need to employ a photoredox catalyst in this transformation. Importantly, this photoinduced transformation allows direct and enantioselective access to α-amino aldehyde products that do not require postreaction manipulation.

| S-EPMC3786402 | biostudies-literature

Direct alkylation of heteroarenes with unactivated bromoalkanes using photoredox gold catalysis.

Project description:Although visible light photoredox catalysis has emerged as a powerful tool for the construction of C-C bonds, common catalysts and/or their photoexcited states suffer from low redox potentials, limiting their applicability to alkyl radical generation from substrates with activated carbon-halogen bonds. Radicals derived from these activated compounds, being highly electrophilic or stabilized, do not undergo efficient addition to heteroarenes. Herein we describe the photocatalytic generation of nucleophilic alkyl radicals from unactivated bromoalkanes as part of a universal and efficient cross-coupling strategy for the direct alkylation of heteroarenes using a dimeric gold(i) photoredox catalyst, [Au2(bis(diphenylphosphino)methane)2]Cl2. The method proves to be efficient for alkylation of arenes under mild conditions in the absence of directing groups.

| S-EPMC6016576 | 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