Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Ligand-Enabled ?-C(sp(3))-H Olefination of Amines: En Route to Pyrrolidines.

ABSTRACT: Pd(II)-catalyzed olefination of ?-C(sp(3))-H bonds of triflyl (Tf) and 4-nitrobenzenesulfonyl (Ns) protected amines is achieved. Subsequent aza-Wacker oxidative cyclization or conjugate addition of the olefinated intermediates provides a variety of C-2 alkylated pyrrolidines. Three pyridine- and quinoline-based ligands are developed to match different classes of amine substrates, demonstrating a rare example of ligand-enabled C(sp(3))-H olefination reactions. The use of Ns protecting group to direct C(sp(3))-H activation of alkyl amines is also a significant step toward practical C-H functionalizations of alkyl amines.

SUBMITTER: Jiang H

PROVIDER: S-EPMC4817546 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Ligand-Enabled γ-C(sp(3))-H Olefination of Amines: En Route to Pyrrolidines.

Jiang Heng H He Jian J Liu Tao T Yu Jin-Quan JQ

Journal of the American Chemical Society 20160204 6

Pd(II)-catalyzed olefination of γ-C(sp(3))-H bonds of triflyl (Tf) and 4-nitrobenzenesulfonyl (Ns) protected amines is achieved. Subsequent aza-Wacker oxidative cyclization or conjugate addition of the olefinated intermediates provides a variety of C-2 alkylated pyrrolidines. Three pyridine- and quinoline-based ligands are developed to match different classes of amine substrates, demonstrating a rare example of ligand-enabled C(sp(3))-H olefination reactions. The use of Ns protecting group to di ...[more]

PMID: 26796676

Similar Datasets

Ligand-Promoted C(sp(3) )-H Olefination en Route to Multi-functionalized Pyrazoles.

Project description:A Pd-catalyzed/N-heterocycle-directed C(sp(3) )-H olefination has been developed. The monoprotected amino acid ligand (MPAA) is found to significantly promote Pd-catalyzed C(sp(3) )-H olefination for the first time. Cu(OAc)2 instead of Ag(+) salts are used as the terminal oxidant. This reaction provides a useful method for the synthesis of alkylated pyrazoles.

| S-EPMC4944759 | biostudies-literature

Ligand-enabled γ-C-H olefination and carbonylation: construction of β-quaternary carbon centers.

Project description:Monoselective γ-C-H olefination and carbonylation of aliphatic acids has been accomplished by using a combination of a quinoline-based ligand and a weakly coordinating amide directing group. The reaction provides a new route for constructing richly functionalized all-carbon quaternary carbon centers at the β-position of aliphatic acids.

| S-EPMC4049142 | biostudies-literature

Ligand-Enabled ?-C(sp3 )-H Olefination of Free Carboxylic Acids.

Project description:We report the ligand-enabled C-H activation/olefination of free carboxylic acids in the ?-position. Through an intramolecular Michael addition, ?-lactones are obtained as products. Two distinct ligand classes are identified that enable the challenging palladium-catalyzed activation of free carboxylic acids in the ?-position. The developed protocol features a wide range of acid substrates and olefin reaction partners and is shown to be applicable on a preparatively useful scale. Insights into the underlying reaction mechanism obtained through kinetic studies are reported.

| S-EPMC7496353 | biostudies-literature

Ligand-Enabled γ-C(sp<sup>3</sup>)-H Activation of Ketones.

Project description:We report the first example of Pd(II)-catalyzed γ-C(sp3)-H activation of ketones directed by a practical 2,2-dimethyl aminooxyacetic acid auxiliary. 2-Pyridone ligands are identified to enable C(sp3)-H activation for the first time. A rare six-membered palladacycle intermediate is isolated and characterized to elucidate the reaction mechanism. Both (hetero)arylation and vinylation of γ-C(sp3)-H bonds are demonstrated. Sequential β- and γ-C(sp3)-H (hetero)arylation of muscone showcases the utility of this method for late-stage diversification. A convenient Mn(II)-catalyzed auxiliary removal is also developed to further underscore the practicality of this transformation.

| S-EPMC5851877 | biostudies-literature

Ligand-enabled ortho-C-H olefination of phenylacetic amides with unactivated alkenes.

Project description:Although chelation-assisted C-H olefination has been intensely investigated, Pd(ii)-catalyzed C-H olefination reactions are largely restricted to acrylates and styrenes. Here we report a quinoline-derived ligand that enables the Pd(ii)-catalyzed olefination of the C(sp2)-H bond with simple aliphatic alkenes using a weakly coordinating monodentate amide auxiliary. Oxygen is used as the terminal oxidant with catalytic copper as the co-oxidant. A variety of functional groups in the aliphatic alkenes are tolerated. Upon hydrogenation, the ortho-alkylated product can be accessed. The utility of this reaction is also demonstrated by the late-stage diversification of drug molecules.

| S-EPMC5887099 | biostudies-literature

Ligand-enabled reactivity and selectivity in a synthetically versatile aryl C-H olefination.

Project description:The Mizoroki-Heck reaction, which couples aryl halides with olefins, has been widely used to stitch together the carbogenic cores of numerous complex organic molecules. Given that the position-selective introduction of a halide onto an arene is not always straightforward, direct olefination of aryl carbon-hydrogen (C-H) bonds would obviate the inefficiencies associated with generating halide precursors or their equivalents. However, methods for carrying out such a reaction have suffered from narrow substrate scope and low positional selectivity. We report an operationally simple, atom-economical, carboxylate-directed Pd(II)-catalyzed C-H olefination reaction with phenylacetic acid and 3-phenylpropionic acid substrates, using oxygen at atmospheric pressure as the oxidant. The positional selectivity can be tuned by introducing amino acid derivatives as ligands. We demonstrate the versatility of the method through direct elaboration of commercial drug scaffolds and efficient syntheses of 2-tetralone and naphthoic acid natural product cores.

| S-EPMC2879878 | biostudies-literature

Ligand-assisted palladium-catalyzed C-H alkenylation of aliphatic amines for the synthesis of functionalized pyrrolidines.

Project description:The development of a ligand-assisted Pd-catalyzed C-H alkenylation of aliphatic amines is reported. Our studies indicated that an amino-acid-derived ligand renders the C-H bond activation step reversible and promotes the traditionally difficult alkenylation process. The C(sp3)-H alkenylation proceeds through a 5-membered-ring cyclopalladation pathway that allows access to complex aliphatic heterocycles that could be useful to practioners of synthetic and medicinal chemistry.

| S-EPMC6092717 | biostudies-literature

Pyrrolidines and Piperidines by Ligand-Enabled Aza-Heck Cyclizations and Cascades of N-(Pentafluorobenzoyloxy)carbamates.

Project description:Ligand-enabled aza-Heck cyclizations and cascades of N-(pentafluorobenzoyloxy)carbamates are described. These studies encompass the first examples of efficient non-biased 6-exo aza-Heck cyclizations. The methodology provides direct and flexible access to carbamate protected pyrrolidines and piperidines.

| S-EPMC5969259 | biostudies-literature

Transmissive olefination route to putative "morinol I" lignans.

Project description:A series of morinol-type lignans were rapidly assembled using a Grignard-based transmissive olefination. In combination with palladium-catalyzed arylations, the strategy provides stereoselective access to (7Z,7'E), (7E,7'E), and (7E,7'Z) morinol diastereomers and the (7Z,8'E) and (7E,8'E) conjugated analogues. Critical for the E/Z stereoselectivity is a new, general method for converting alkenenitriles to alkenemethanols that circumvents the enal E/Z isomerization commonly encountered during conventional i-Bu(2)AlH reduction.

| S-EPMC3331789 | biostudies-literature

Ligand-controlled C(sp³)-H arylation and olefination in synthesis of unnatural chiral ?-amino acids.

Project description:The use of ligands to tune the reactivity and selectivity of transition metal catalysts for C(sp(3))-H bond functionalization is a central challenge in synthetic organic chemistry. Herein, we report a rare example of catalyst-controlled C(sp(3))-H arylation using pyridine and quinoline derivatives: The former promotes exclusive monoarylation, whereas the latter activates the catalyst further to achieve diarylation. Successive application of these ligands enables the sequential diarylation of a methyl group in an alanine derivative with two different aryl iodides, affording a wide range of ?-Ar-?-Ar'-?-amino acids with excellent levels of diastereoselectivity (diastereomeric ratio > 20:1). Both configurations of the ?-chiral center can be accessed by choosing the order in which the aryl groups are installed. The use of a quinoline derivative as a ligand also enables C(sp(3))-H olefination of a protected alanine.

| S-EPMC4179246 | 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