Browse
Submit Data
Databases
API
Help

Dataset Information

25 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Ring-Opening Regio-, Diastereo-, and Enantioselective 1,3-Chlorochalcogenation of Cyclopropyl Carbaldehydes.

ABSTRACT: meso-Cyclopropyl carbaldehydes are treated in the presence of an organocatalyst with sulfenyl and selenyl chlorides to afford 1,3-chlorochalcogenated products. The transformation is achieved by a merged iminium-enamine activation. The enantioselective desymmetrization reaction, leading to three adjacent stereocenters, furnished the target products in complete regioselectivity and moderate to high diastereo- and enantioselectivities (d.r. up to 15:1 and e.r. up to 93:7).

SUBMITTER: Wallbaum J

PROVIDER: S-EPMC6680189 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Ring-Opening Regio-, Diastereo-, and Enantioselective 1,3-Chlorochalcogenation of Cyclopropyl Carbaldehydes.

Wallbaum Jan J Garve Lennart K B LK Jones Peter G PG Werz Daniel B DB

Chemistry (Weinheim an der Bergstrasse, Germany) 20161129 52

meso-Cyclopropyl carbaldehydes are treated in the presence of an organocatalyst with sulfenyl and selenyl chlorides to afford 1,3-chlorochalcogenated products. The transformation is achieved by a merged iminium-enamine activation. The enantioselective desymmetrization reaction, leading to three adjacent stereocenters, furnished the target products in complete regioselectivity and moderate to high diastereo- and enantioselectivities (d.r. up to 15:1 and e.r. up to 93:7). ...[more]

PMID: 27868248

Similar Datasets

Diastereo- and Enantioselective Iridium Catalyzed Carbonyl (?-Cyclopropyl)allylation via Transfer Hydrogenation.

Project description:The first examples of diastereo- and enantioselective carbonyl ?-(cyclopropyl)allylation are reported. Under the conditions of iridium catalyzed transfer hydrogenation using the chiral precatalyst (R)-Ir-I modified by SEGPHOS, carbonyl ?-(cyclopropyl)allylation may be achieved with equal facility from alcohol or aldehyde oxidation levels. This methodology provides a conduit to hitherto inaccessible inaccessible enantiomerically enriched cyclopropane-containing architectures.

| S-EPMC4627847 | biostudies-literature

Mo-catalyzed regio-, diastereo-, and enantioselective allylic alkylation of 3-aryloxindoles.

Project description:A highly regio-, diastereo-, and enantioselective allylic alkylation reaction mediated by a chiral molybdenum catalyst has been developed as a novel entry into synthetically versatile 3-alkyl-3-aryloxindoles. Extremely bulky nucleophiles were employed to form a quaternary center and an adjacent tertiary center asymmetrically concurrently. The regio- and diastereoselectivity of the reaction is dependent upon the steric and electronic nature of the nucleophiles to an unusual degree. A reaction mechanism based on the bonding modes of molybdenum enolate complexes was discussed.

| S-EPMC2536500 | biostudies-literature

Palladium-catalyzed regio-, diastereo-, and enantioselective benzylic allylation of 2-substituted pyridines.

Project description:We report a new method for the highly regio-, diastereo-, and enantioselective palladium-catalyzed allylic alkylation of 2-substituted pyridines that allows for the formation of homoallylic stereocenters containing alkyl, aryl, heteroaryl, and nitrogen substituents. When the reaction is conducted with asymmetric acyclic electrophiles, both linear and branched products may be obtained exclusively by selecting the appropriate regioisomeric starting material and ligand, an example of the "memory effect." Deuterium-labeling studies reveal that though no such phenomenon occurs with racemic cyclic electrophiles, the chiral ligand employed reacts kinetically faster with the enantiomer of the substrate for which it is "matched" and yet eventually converts all "mismatched" substrate to product.

| S-EPMC3235048 | biostudies-literature

Photoredox cobalt-catalyzed regio-, diastereo- and enantioselective propargylation of aldehydes via propargyl radicals.

Project description:Catalytic enantioselective introduction of a propargyl group constitutes one of the most important carbon-carbon forming reactions, as it is versatile to be transformed into diverse functional groups and frequently used in the synthesis of natural products and biologically active molecules. Stereoconvergent transformations of racemic propargyl precursors to a single enantiomer of products via propargyl radicals represent a powerful strategy and provide new reactivity. However, only few Cu- or Ni-catalyzed protocols have been developed with limited reaction modes. Herein, a photoredox/cobalt-catalyzed regio-, diastereo- and enantioselective propargyl addition to aldehydes via propargyl radicals is presented, enabling construction of a broad scope of homopropargyl alcohols that are otherwise difficult to access in high efficiency and stereoselectivity from racemic propargyl carbonates. Mechanistic studies and DFT calculations provided evidence for the involvement of propargyl radicals, the origin of the stereoconvergent process and the stereochemical models.

| S-EPMC10415309 | biostudies-literature

Regio-, Diastereo-, and Enantioselective Decarboxylative Hydroaminoalkylation of Dienol Ethers Enabled by Dual Palladium/Photoredox Catalysis.

Project description:Intermolecular photocatalytic hydroaminoalkylation (HAA) of alkenes have emerged as a powerful method for the construction of alkyl amines. Although there are some studies aiming at stereoselective photocatalytic HAA reactions, the alkenes are limited to electrophilic alkenes. Herein, we report a highly regio-, diastereo-, and enantioselective HAA of electron-rich dienol ethers and α-amino radicals derived from α-amino acids using a unified photoredox and palladium catalytic system. This decarboxylative 1,2-Markovnikov addition enables the construction of vicinal amino tertiary ethers with high levels of regio- (up to >19 : 1 rr), diastereo- (up to >19 : 1 dr), and enantioselectivity control (up to >99 % ee). Mechanistic studies support a reversible hydropalladation as a key step.

| S-EPMC9314026 | biostudies-literature

Ring-Opening 1,3-Halochalcogenation of Cyclopropane Dicarboxylates.

Project description:Donor-acceptor cyclopropanes with two geminal carboxylic esters are reacted with chalcogenyl chlorides and bromides to afford ring-opened products bearing the halogen atoms in the 1-position, adjacent to the donor, and the chalcogenyl residue in the 3-position next to the two acceptor groups. A variety of different donors (e.g., aryl, N, and O) are used. The stereospecificity of the reaction is demonstrated by using a chiral starting material.

| S-EPMC5223275 | biostudies-literature

Recent advances in enantioselective ring-opening polymerization and copolymerization.

Project description:Precisely controlling macromolecular stereochemistry and sequences is a powerful strategy for manipulating polymer properties. Controlled synthetic routes to prepare degradable polyester, polycarbonate, and polyether are of recent interest due to the need for sustainable materials as alternatives to petrochemical-based polyolefins. Enantioselective ring-opening polymerization and ring-opening copolymerization of racemic monomers offer access to stereoregular polymers, specifically enantiopure polymers that form stereocomplexes with improved physicochemical and mechanical properties. Here, we highlight the state-of-the-art of this polymerization chemistry that can produce microstructure-defined polymers. In particular, the structures and performances of various homogeneous enantioselective catalysts are presented. Trends and future challenges of such chemistry are discussed.

| S-EPMC10541874 | biostudies-literature

Catalytic Chemo-, Regio-, Diastereo-, and Enantioselective Bromochlorination of Unsaturated Systems Enabled by Lewis Base-Controlled Chloride Release.

Project description:A new strategy is described for the Lewis base-catalyzed bromochlorination of unsaturated systems that is mechanistically distinct from prior methodologies. The novelty of this method hinges on the utilization of thionyl chloride as a latent chloride source in combination with as little as 1 mol % of triphenylphosphine or triphenylphosphine oxide as Lewis basic activators. This metal-free, catalytic chemo-, regio-, and diastereoselective bromochlorination of alkenes and alkynes exhibits excellent site selectivity in polyunsaturated systems and provides access to a wide variety of vicinal bromochlorides with up to >20:1 regio- and diastereoselectivity. The precision installation of Br, Cl, and I in various combinations is also demonstrated by simply varying the commercial halogenating reagents employed. Notably, when a chiral Lewis base promoter is employed, an enantioselective bromochlorination of chalcones is possible with up to a 92:8 enantiomeric ratio when utilizing only 1-3 mol % of (DHQD)2PHAL.

| S-EPMC9945878 | biostudies-literature

Regio- and enantioselective CuH-catalyzed 1,2- and 1,4-hydrosilylation of 1,3-enynes.

Project description:We report a copper-catalyzed ligand-controlled selective 1,2- and 1,4-hydrosilylation of 1,3-enynes, which furnishes enantiomerically enriched propargyl- and 1,2-allenylsilane products in high yields with excellent enantioselectivities (up to 99% ee). This reaction proceeds under mild conditions, shows broad substrate scope for both 1,3-enynes and trihydrosilanes, and displays excellent regioselectivities. Mechanistic studies based on deuterium-labeling reactions and density functional theory (DFT) calculations suggest that allenylcopper is the dominant reactive intermediate under both 1,2- and 1,4-hydrosilylation conditions, and it undergoes metathesis with silanes via selective four-membered or six-membered transition state, depending on the nature of the ligand. The weak interactions between the ligands and the reacting partners are found to be the key controlling factor for the observed regioselectivity switch. The origin of high enantiocontrol in the 1,4-hydrosilylation is also revealed by high level DLPNO-CCSD(T) calculations.

| S-EPMC10439940 | biostudies-literature

Gold(I)-catalyzed diastereo- and enantioselective 1,3-dipolar cycloaddition and Mannich reactions of azlactones.

Project description:Azlactones participate in stereoselective reactions with electron-deficient alkenes and N-sulfonyl aldimines to give products of 1,3-dipolar cycloaddition and Mannich addition reactions, respectively. Both of these reactions proceed with good to excellent diastereo- and enantioselectivity using a single class of gold catalysts, namely C(2)-symmetric bis(phosphinegold(I) carboxylate) complexes. The development of the azlactone Mannich reaction to provide fully protected anti-?,?-diamino acid derivatives is described. 1,3-Dipolar cycloaddition reactions of several acyclic 1,2-disubstituted alkenes and the chemistry of the resultant cycloadducts are examined to probe the stereochemical course of this reaction. Reaction kinetics and tandem mass spectrometry studies of both the cycloaddition and Mannich reactions are reported. These studies support a mechanism in which the gold complexes catalyze addition reactions through nucleophile activation rather than the more typical activation of the electrophilic reaction component.

| S-EPMC3056178 | 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