Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Electrooxidative palladium- and enantioselective rhodium-catalyzed [3 + 2] spiroannulations.

ABSTRACT: Despite indisputable progress in the development of electrochemical transformations, electrocatalytic annulations for the synthesis of biologically relevant three-dimensional spirocyclic compounds has as of yet not been accomplished. In sharp contrast, herein, we describe the palladaelectro-catalyzed C-H activation/[3 + 2] spiroannulation of alkynes by 1-aryl-2-naphthols. Likewise, a cationic rhodium(iii) catalyst was shown to enable electrooxidative [3 + 2] spiroannulations via formal C(sp³)-H activations. The versatile spiroannulations featured a broad substrate scope, employing electricity as a green oxidant in lieu of stoichiometric chemical oxidants under mild conditions. An array of spirocyclic enones and diverse spiropyrazolones, bearing all-carbon quaternary stereogenic centers were thereby accessed in a user-friendly undivided cell setup, with molecular hydrogen as the sole byproduct.

SUBMITTER: Wei W

PROVIDER: S-EPMC8890123 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Electrooxidative palladium- and enantioselective rhodium-catalyzed [3 + 2] spiroannulations.

Wei Wen W Scheremetjew Alexej A Ackermann Lutz L

Chemical science 20220210 9

Despite indisputable progress in the development of electrochemical transformations, electrocatalytic annulations for the synthesis of biologically relevant three-dimensional spirocyclic compounds has as of yet not been accomplished. In sharp contrast, herein, we describe the palladaelectro-catalyzed C-H activation/[3 + 2] spiroannulation of alkynes by 1-aryl-2-naphthols. Likewise, a cationic rhodium(iii) catalyst was shown to enable electrooxidative [3 + 2] spiroannulations <i>via</i> formal C( ...[more]

PMID: 35340855

Similar Datasets

Rhodium-Catalyzed Electrooxidative C-H Olefination of Benzamides.

Project description:Metal-catalyzed chelation-assisted C-H olefinations have emerged as powerful tools for the construction of functionalized alkenes. Herein, we describe the rhoda-electrocatalyzed C-H activation/alkenylation of arenes. The olefinations of challenging electron-poor benzamides were thus accomplished in a fully dehydrogenative fashion under electrochemical conditions, avoiding stoichiometric chemical oxidants, and with H2 as the only byproduct. This versatile alkenylation reaction also features broad substrate scope and used electricity as a green oxidant.

| S-EPMC7496262 | biostudies-literature

Palladium-Catalyzed Electrooxidative Double C-H Arylation.

Project description:The electrochemical transition metal-catalyzed cross-dehydrogenative reaction has emerged as a promising platform to achieve a sustainable and atom-economic organic synthesis that avoids hazardous oxidants and minimizes undesired byproducts and circuitous functional group operations. However, a poor mechanistic understanding still prevents the widespread adoption of this strategy. In this regard, we herein present an electrochemical palladium-catalyzed oxidative coupling strategy to access biaryls in the absence of a stoichiometric chemical oxidant. The robust palladaelectrocatalysis considerably suppresses the occurrence of homocoupling and oxygenation, being compatible even with electron-deficient arenes. Late-stage functionalization and Boscalid precursor synthesis further highlighted the practical importance of our electrolysis. Remarkably, mechanistic studies including the evaluation of the reaction order of each component by variable time normalization analysis (VTNA) and initial rate analysis, H/D exchange experiment, kinetic isotope effect, and stoichiometric organometallic experiments provided strong support for the involvement of transmetalation between two organopalladium complexes in the turnover limiting step. Therefore, matching the concentrations or lifetimes of two distinct organopalladium intermediates is revealed to be a pivot to the success of electrooxidative catalysis. Moreover, the presence of cationic copper(II) seems to contribute to the stabilization of the palladium(0) catalyst instead of playing a role in the oxidation of the catalyst.

| S-EPMC10785825 | biostudies-literature

Electrooxidative Rhodium-Catalyzed [5+2] Annulations via C-H/O-H Activations.

Project description:Electrooxidative annulations involving mild transition metal-catalyzed C-H activation have emerged as a transformative strategy for the rapid construction of five- and six-membered heterocycles. In contrast, we herein describe the first electrochemical metal-catalyzed [5+2] cycloadditions to assemble valuable seven-membered benzoxepine skeletons by C-H/O-H activation. The efficient alkyne annulation featured ample substrate scope, using electricity as the only oxidant. Mechanistic studies provided strong support for a rhodium(III/I) regime, involving a benzoxepine-coordinated rhodium(I) sandwich complex as the catalyst resting state, which was re-oxidized to rhodium(III) by anodic oxidation.

| S-EPMC7986427 | biostudies-literature

Palladium-Catalyzed, Enantioselective Heine Reaction.

Project description:Aziridines are important synthetic intermediates for the generation of nitrogen-containing molecules. N-Acylaziridines undergo rearrangement by ring expansion to produce oxazolines, a process known as the Heine reaction. The first catalytic, enantioselective Heine reaction is reported for meso-N-acylaziridines where a palladium(II)-diphosphine complex is employed. The highly enantioenriched oxazoline products are valuable organic synthons and potential ligands for transition-metal catalysis.

| S-EPMC4933940 | biostudies-literature

Rhodium-catalyzed enantioselective cyclopropanation of electron deficient alkenes.

Project description:The rhodium-catalyzed reaction of electron-deficient alkenes with substituted aryldiazoacetates and vinyldiazoacetates results in highly stereoselective cyclopropanations. With adamantylglycine derived catalyst Rh2(S-TCPTAD)4, high asymmetric induction (up to 98% ee) can be obtained with a range of substrates. Computational studies suggest that the reaction is facilitated by weak interaction between the carbenoid and the substrate carbonyl but subsequently proceeds via different pathways depending on the nature of the carbonyl.. Acrylates and acrylamides result in the formation of cyclopropanation products while the use of unsaturated aldehydes and ketones results in the formation of epoxides.

| S-EPMC3773518 | biostudies-literature

Silicon-oriented regio- and enantioselective rhodium-catalyzed hydroformylation.

Project description:Hydroformylation of 1,2-disubstituted alkenes usually occurs at the α position of the directing heteroatom such as oxygen atom and nitrogen atom. By contrast, to achieve hydroformylation on the β position of the heteroatom is a tough task. Herein, we report the asymmetric rhodium-catalyzed hydroformylation of 1,2-disubstituted alkenylsilanes with excellent regioselectivity at the β position (relative to the silicon heteroatom) and enantioselectivity. In a synthetic sense, we achieve the asymmetric hydroformylation on the β position of the oxygen atom indirectly by using the silicon group as a surrogate for the hydroxyl. Density functional theory (DFT) calculations are carried out to examine energetics of the whole reaction path for Rh/YanPhos-catalyzed asymmetric hydroformylation and understand its regioselectivity and enantioselectivity. Our computational study suggests that the silicon group can activate the substrate and is critical for the regioselectivity.

| S-EPMC5966446 | biostudies-literature

Rhodium-Catalyzed Enantioselective Hydroamination of Alkynes with Indolines.

Project description:The hydroamination of internal alkynes via tandem rhodium catalysis gives branched N-allylic indolines with high regio- and enantioselectivity. An acid switch provides access to the linear isomer in preference to the branched isomer by an isomerization mechanism. Mechanistic studies suggest formation of an allene intermediate, which undergoes hydroamination to generate allylic amines instead of the enamine or imine products typically observed in alkyne hydroaminations.

| S-EPMC4870006 | biostudies-literature

Ligand-Controlled Regiodivergent Enantioselective Rhodium-Catalyzed Alkene Hydroboration.

Project description:Regiocontrol in the rhodium-catalyzed boration of vinyl arenes is typically dominated by the presence of the conjugated aryl substituent. However, small differences in TADDOL-derived chiral monophosphite ligands can override this effect and direct rhodium-catalyzed hydroboration of β-aryl and β-heteroaryl methylidenes by pinacolborane to selectively produce either chiral primary or tertiary borated products. The regiodivergent behavior is coupled with enantiodivergent addition of the borane. The nature of the TADDOL backbone substituents and that of the phosphite moiety function synergistically to direct the sense and extent of regioselectivity and enantioinduction. Twenty substrates are shown to undergo each reaction mode with regioselectivity values reaching greater than 20:1 and enantiomer ratios reaching up to 98:2. A variety of subsequent transformations illustrate the potential utility of each product.

| S-EPMC6663592 | biostudies-literature

Palladium-catalyzed enantioselective 1,1-fluoroarylation of aminoalkenes.

Project description:The development of an enantioselective palladium-catalyzed 1,1-fluoroarylation of unactivated aminoalkenes is described. The reaction uses arylboronic acids as the arene source and Selectfluor as the fluorine source to generate benzylic fluorides in good yields with excellent enantioselectivities. This transformation, likely proceeding through an oxidative Heck mechanism, affords 1,1-difunctionalized alkene products.

| S-EPMC4601482 | biostudies-literature

Palladium-catalyzed enantioselective alkenylation of alkenylbenzene derivatives.

Project description:A regioselective and enantioselective palladium-catalyzed relay Heck alkenylation of alkenylbenzene derivatives to construct remote stereocenters is disclosed. Various β-substituted styrenes were readily obtained in moderate yields with good to excellent levels of enantioselectivity. This strategy provides rapid access to enantioenriched δ, ε, ζ, and η-alkenyl aryl compounds from simple starting materials. Mechanistic studies suggest that termination of the relay reaction is controlled by affinity of the arene for the Pd complex during migration.

| S-EPMC6685350 | 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