Browse
Submit Data
Databases
API
Help

Dataset Information

9 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Enantio- and Diastereoswitchable C-H Arylation of Methylene Groups in Cycloalkanes.

ABSTRACT: A complementary set of chiral N,N-ligands enables the Pd-catalyzed ?-C-H arylation of unbiased internal methylene groups in good yield and with high levels of enantio- and diastereoinduction. Both the dia- and enantioselectivity can be reversed, thus allowing the selective arylation of any of the four ?-C-H bonds in cycloalkanecarboxamides of various ring sizes. The method is applicable to a broad range of aryl iodides with electron-withdrawing and -donating substituents in the o-, m-, or p-position.

SUBMITTER: Andra MS

PROVIDER: S-EPMC6634307 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Enantio- and Diastereoswitchable C-H Arylation of Methylene Groups in Cycloalkanes.

Andrä Michal S MS Schifferer Lukas L Pollok Corina H CH Merten Christian C Gooßen Lukas J LJ Yu Jin-Quan JQ

Chemistry (Weinheim an der Bergstrasse, Germany) 20190527 36

A complementary set of chiral N,N-ligands enables the Pd-catalyzed β-C-H arylation of unbiased internal methylene groups in good yield and with high levels of enantio- and diastereoinduction. Both the dia- and enantioselectivity can be reversed, thus allowing the selective arylation of any of the four β-C-H bonds in cycloalkanecarboxamides of various ring sizes. The method is applicable to a broad range of aryl iodides with electron-withdrawing and -donating substituents in the o-, m-, or p-posi ...[more]

PMID: 31062889

Similar Datasets

Catalytic Alkyne Arylation Using Traceless Directing Groups.

Project description:By using Pd0 /Mandyphos, we achieved a three-component aminoarylation of alkynes to generate enamines, which are then hydrolyzed to either α-arylphenones or α,α-diarylketones. This Pd-catalyzed method overcomes established known pathways to enable the use of amines as traceless directing groups for C-C bond formation.

| S-EPMC6661160 | biostudies-literature

Ligand-promoted palladium-catalyzed β-methylene C-H arylation of primary aldehydes.

Project description:The transient directing group (TDG) strategy allowed long awaited access to the direct β-C(sp3)-H functionalization of unmasked aliphatic aldehydes via palladium catalysis. However, the current techniques are restricted to terminal methyl functionalization, limiting their structural scopes and applicability. Herein, we report the development of a direct Pd-catalyzed methylene β-C-H arylation of linear unmasked aldehydes by using 3-amino-3-methylbutanoic acid as a TDG and 2-pyridone as an external ligand. Density functional theory calculations provided insights into the reaction mechanism and shed light on the roles of the external and transient directing ligands in the catalytic transformation.

| S-EPMC9132077 | biostudies-literature

Stereochemistry of the incorporation of valine methyl groups into methylene groups in cephalosporin C.

Project description:'Chiral methyl valines', i.e. samples of valine labelled stereospecifically in the methyl groups with 2H and 3H, were incorporated into cephalosporin C by a suspension of washed cells of Cephalosporium acremonium. Analysis by 3H n.m.r. of the cephalosporin C produced showed that the conversion of the 3-pro-S-methyl group of valine into the acetoxymethyl side-chain was a highly stereospecific process. By contrast, conversion of the 3-pro-R-methyl group into the endocyclic methylene group of the dihydrothiazine ring was shown to proceed by a non-stereospecific process.

| S-EPMC1144242 | biostudies-other

Ligand-Enabled β-Methylene C(sp<sup>3</sup> )-H Arylation of Masked Aliphatic Alcohols.

Project description:Despite recent advances, reactivity and site-selectivity remain significant obstacles for the practical application of C(sp3 )-H bond functionalization methods. Here, we describe a system that combines a salicylic-aldehyde-derived L,X-type directing group with an electron-deficient 2-pyridone ligand to enable the β-methylene C(sp3 )-H arylation of aliphatic alcohols, which has not been possible previously. Notably, this protocol is compatible with heterocycles embedded in both alcohol substrates and aryl coupling partners. A site- and stereo-specific annulation of dihydrocholesterol and the synthesis of a key intermediate of englitazone illustrate the practicality of this method.

| S-EPMC7219561 | biostudies-literature

Methylene C(sp<sup>3</sup>)-H Arylation of Aliphatic Ketones Using a Transient Directing Group.

Project description:Palladium-catalyzed methylene β-C(sp3)-H arylation of aliphatic ketones using a transient directing group is developed. The use of α-benzyl β-alanine directing group that forms a six-membered chelation with palladium is crucial for promoting the methylene C(sp3)-H bond activation.

| S-EPMC5640319 | biostudies-literature

Ligand-Enabled ?-C-H Arylation of ?-Amino Acids Without Installing Exogenous Directing Groups.

Project description:Herein we report acid-directed ?-C(sp3 )-H arylation of ?-amino acids enabled by pyridine-type ligands. This reaction does not require the installation of an exogenous directing group, is scalable, and enables the preparation of Fmoc-protected unnatural amino acids in three steps. The pyridine-type ligands are crucial for the development of this new C(sp3 )-H arylation.

| S-EPMC5302090 | biostudies-literature

Radical cation Diels-Alder reactions of arylidene cycloalkanes.

Project description:TiO2 photoelectrochemical and electrochemical radical cation Diels-Alder reactions of arylidene cycloalkanes are described, leading to the construction of spiro ring systems. Although the mechanism remains an open question, arylidene cyclobutanes are found to be much more effective in the reaction than other cycloalkanes. Since the reaction is completed with a substoichiometric amount of electricity, a radical cation chain pathway is likely to be involved.

| S-EPMC9443414 | biostudies-literature

Enantio-sensitive unidirectional light bending.

Project description:Structured light, which exhibits nontrivial intensity, phase, and polarization patterns in space, has key applications ranging from imaging and 3D micromanipulation to classical and quantum communication. However, to date, its application to molecular chirality has been limited by the weakness of magnetic interactions. Here we structure light's local handedness in space to introduce and realize an enantio-sensitive interferometer for efficient chiral recognition without magnetic interactions, which can be seen as an enantio-sensitive version of Young's double slit experiment. Upon interaction with isotropic chiral media, such chirality-structured light effectively creates chiral emitters of opposite handedness, located at different positions in space. We show that if the distribution of light's handedness breaks left-right symmetry, the interference of these chiral emitters leads to unidirectional bending of the emitted light, in opposite directions in media of opposite handedness, even if the number of the left-handed and right-handed emitters excited in the medium is exactly the same. Our work introduces the concepts of polarization of chirality and chirality-polarized light, exposes the immense potential of sculpting light's local chirality, and offers novel opportunities for efficient chiral discrimination, enantio-sensitive optical molecular fingerprinting and imaging on ultrafast time scales.

| S-EPMC8225816 | biostudies-literature

Enantioselective oxygenation of exocyclic methylene groups by a manganese porphyrin catalyst with a chiral recognition site.

Project description:The natural enzyme cytochrome P450 is widely recognised for its unique ability to catalyse highly selective oxygen insertion reactions into unactivated C-H bonds under mild conditions. Its exceptional potential for organic synthesis served as an inspiration for the presented biomimetic hydroxylation approach. Via a remote hydrogen bonding motif a high enantioselectivity in the manganese-catalysed oxygenation of quinolone analogues (27 examples, 18-64% yield, 80-99% ee) was achieved. The site-selectivity was completely altered in favour of a less reactive but more accessible position.

| S-EPMC8150113 | biostudies-literature

New chiral phosphoramidite complexes of iron as catalytic precursors in the oxidation of activated methylene groups.

Project description:New phosphoramidite complexes of iron were synthesized and structurally characterized. Reaction of the known chiral phosphoramidites (RO)2PNR'2 (R = binaphthyl, R' = CH3, 1a; R = binaphthyl, R' = benzyl, 1b) with [FeBr(Cp)(CO)2] afforded the title compounds [FeBr(Cp)(CO)(1a,b)] (4a,b) in 34 and 65 % isolated yields as mixtures of diastereomers, since both the metal and the ligand are stereogenic. Similarly, reaction of 1b with [Fe(Cp)I(CO)2] in the presence of catalytic [Fe(Cp)(CO)2]2 afforded [Fe(Cp)I(CO)(1b)] (5b) in 81% yield as a mixture of diastereomers. The molecular structures of 4a, 4b and 5 were determined, revealing a pseudo octahedral coordination geometry about the iron center. The new metal complexes are catalytically active in the oxidation of benzylic methylene groups to the corresponding ketones, utilizing t-BuOOH as oxidant (2 mol% catalyst, 36 h, room temperature, 31-80% yield).

| S-EPMC6257337 | 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