Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Oxidative organocatalysed enantioselective coupling of indoles with aldehydes that forms quaternary carbon stereocentres.

ABSTRACT: The first organocatalysed, metal-free cross-nucleophile coupling of indoles with α-branched aldehydes forming acyclic stereoselective quaternary carbon centres is presented. Applying an amino acid-derived catalyst with suitable organic oxidants affords the desired enantioenriched indole functionalised products with moderate to excellent yield and enantioselectivity. Two metal-free oxidative protocols employing either DDQ or a sequential approach that uses two organocatalysts to facilitate the use of O₂ as the terminal oxidant are disclosed. These methods are compatible with various indoles ranging from electron-rich to -deficient substituents at the C-2, -5, -6, and -7-positions reacting with a series of different α-branched aldehydes.

SUBMITTER: Rezayee NM

PROVIDER: S-EPMC6432613 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Oxidative organocatalysed enantioselective coupling of indoles with aldehydes that forms quaternary carbon stereocentres.

Rezayee Nomaan M NM Lauridsen Vibeke H VH Næsborg Line L Nguyen Thanh V Q TVQ Tobiesen Henriette N HN Jørgensen Karl Anker KA

Chemical science 20190213 12

The first organocatalysed, metal-free cross-nucleophile coupling of indoles with α-branched aldehydes forming acyclic stereoselective quaternary carbon centres is presented. Applying an amino acid-derived catalyst with suitable organic oxidants affords the desired enantioenriched indole functionalised products with moderate to excellent yield and enantioselectivity. Two metal-free oxidative protocols employing either DDQ or a sequential approach that uses two organocatalysts to facilitate the us ...[more]

PMID: 30996950

Similar Datasets

Enantioselective construction of remote quaternary stereocentres.

Project description:Small molecules that contain all-carbon quaternary stereocentres-carbon atoms bonded to four distinct carbon substituents-are found in many secondary metabolites and some pharmaceutical agents. The construction of such compounds in an enantioselective fashion remains a long-standing challenge to synthetic organic chemists. In particular, methods for synthesizing quaternary stereocentres that are remote from other functional groups are underdeveloped. Here we report a catalytic and enantioselective intermolecular Heck-type reaction of trisubstituted-alkenyl alcohols with aryl boronic acids. This method provides direct access to quaternary all-carbon-substituted β-, γ-, δ-, ε- or ζ-aryl carbonyl compounds, because the unsaturation of the alkene is relayed to the alcohol, resulting in the formation of a carbonyl group. The scope of the process also includes incorporation of pre-existing stereocentres along the alkyl chain, which links the alkene and the alcohol, in which the stereocentre is preserved. The method described allows access to diverse molecular building blocks containing an enantiomerically enriched quaternary centre.

| S-EPMC4007023 | biostudies-literature

Enantioselective allylic alkylation of stereodefined polysubstituted copper enolates as an entry to acyclic quaternary carbon stereocentres.

Project description:A sequence of regio- and stereoselective carbometalation followed by oxidation of ynamides leads to stereodefined fully substituted enolates that subsequently react with various functionalized allyl bromide reagents to provide the expected products possessing an enantiomerically pure quaternary carbon stereocentre in the α-position to the carbonyl group in excellent yields and enantiomeric ratios after cleavage of the oxazolidinone moiety. Three new bonds are formed in a single-pot operation.

| S-EPMC5358538 | biostudies-literature

Modular, Catalytic Enantioselective Construction of Quaternary Carbon Stereocenters by Sequential Cross-Coupling Reactions.

Project description:The catalytic Suzuki-Miyaura cross-coupling with chiral γ,γ-disubstituted allylboronates in the presence of RuPhos ligand occurs with high regioselectivity and enantiospecificity, furnishing nonracemic compounds with quaternary centers. Mechanistic experiments suggest that the reaction occurs by transmetalation with allyl migration, followed by rapid reductive elimination.

| S-EPMC5510877 | biostudies-literature

Enantioselective reductive multicomponent coupling reactions between isatins and aldehydes.

Project description:A metal-free stereoselective reductive coupling reaction between isatins and aldehydes is reported. The reaction relies on commercial diethyl phosphite (∼€70 kg-1) as the stoichiometric reductant. Base-catalyzed Pudovik addition and phosphonate/phosphate rearrangement achieved polarity inversion on the isatin, and the derived carbanions were trapped by aldehydes with subsequent dialkoxyphosphinyl migration. Chiral iminophosphoranes were used as basic catalysts to achieve high diastereo- and enantioselectivities with excellent yields.

| S-EPMC4618493 | biostudies-literature

Hypoiodite-Catalyzed Oxidative Umpolung of Indoles for Enantioselective Dearomatization.

Project description:Here we report the oxidative umpolung of 2,3-disubstituted indoles toward enantioselective dearomative aza-spirocyclization to give the corresponding spiroindolenines using chiral quaternary ammonium hypoiodite catalysis. Mechanistic studies revealed the umpolung reactivity of C3 of indoles by iodination of the indole nitrogen atom. Moreover, the introduction of pyrazole as an electron-withdrawing auxiliary group at C2 suppressed a competitive dissociative racemic pathway, and enantioselective spirocyclization proceeded to give not only spiropyrrolidines but also four-membered spiroazetidines that are otherwise difficult to access.

| S-EPMC8991020 | biostudies-literature

Enantioselective construction of all-carbon quaternary centers by branch-selective Pd-catalyzed allyl-allyl cross-coupling.

Project description:The Pd-catalyzed cross-coupling of racemic tertiary allylic carbonates and allylboronates is described. This reaction generates all-carbon quaternary centers in a highly regioselective and enantioselective fashion. The outcome of these reactions is consistent with a process that proceeds by way of 3,3'-reductive elimination of bis(η(1)-allyl)palladium intermediates. Strategies for distinguishing the product alkenes and application to the synthesis of (+)-α-cuparenone are also described.

| S-EPMC3131072 | biostudies-literature

Cross-dehydrogenative coupling enables enantioselective access to CF<sub>3</sub>-substituted all-carbon quaternary stereocenters.

Project description:A cross-dehydrogenative coupling strategy for enantioselective access to acyclic CF3-substituted all-carbon quaternary stereocenters has been established. By using catalytic DDQ with MnO2 as an inexpensive terminal oxidant, asymmetric cross coupling of racemic δ-CF3-substituted phenols with indoles proceeded smoothly, providing CF3-bearing all-carbon quaternary stereocenters with excellent chemo- and enantioselectivities. The generality of the strategy is further demonstrated by efficient construction of all-carbon quaternary stereocenters bearing other polyfluoroalkyl and perfluoroalkyl groups such as CF2Cl, C2F5, and C3F7.

| S-EPMC8157275 | biostudies-literature

Enantioselective Dehydrogenative Heck Arylations of Trisubstituted Alkenes with Indoles to Construct Quaternary Stereocenters.

Project description:An enantioselective, intermolecular dehydrogenative Heck arylation of trisubstituted alkenes to construct remote quaternary stereocenters has been developed. Using a new chiral pyridine oxazoline ligand, good to high enantioselectivity is achieved for various combinations of indole derivatives and trisubstituted alkenes. However, some combinations of substrates led to lower enantioselectivity, which provided the impetus to use structure enantioselectivity correlations to design a better performing ligand.

| S-EPMC5039010 | biostudies-literature

Thiourea-catalyzed enantioselective addition of indoles to pyrones: alkaloid cores with quaternary carbons.

Project description:We report the development of a catalytic method for the enantioselective addition of indoles to pyrone-derived electrophiles. Arylpyrrolidino-derived thioureas catalyze the addition with high stereoselectivity in the presence of catalytic quantities of an achiral Brønsted acid. The indole-pyrone adducts feature a quaternary stereocenter and represent an unusual class of indolines bearing structural resemblance to the hybrid natural product pleiocarpamine.

| S-EPMC4235369 | biostudies-literature

Oxidative Coupling of 3-Oxindoles with Indoles and Arenes.

Project description:A highly efficient method for the oxidative coupling of 2-substituted 3-oxindoles with aromatic compounds to form 2,2-disubstituted indolin-3-ones with broad scope is described. This work utilized oxygen as the terminal oxidant and a base-metal catalyst under mild conditions instead of toxic/precious-metal reagents and higher-molecular-weight oxidants. Quaternary structures were produced in modest-to-excellent yields (up to 96 %) without prefunctionalization.

| S-EPMC6703824 | 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