Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Palladium-Catalyzed Arylation of C(sp²)-H Bonds with 2-(1-Methylhydrazinyl)pyridine as the Bidentate Directing Group.

ABSTRACT: Palladium-catalyzed C(sp²)-H arylation of ortho C-H bonds involving 2-(1-methylhydrazinyl)pyridine (MHP) as the directing group has been investigated. The reaction proceeds smoothly under an air atmosphere to generate biaryl derivatives in an environmentally friendly manner while tolerating a wide range of functional groups. Notably, the directing group present in the product could be easily removed under mild reductive conditions.

SUBMITTER: Wei J

PROVIDER: S-EPMC8495716 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Palladium-Catalyzed C(sp3 )-H Arylation of Primary Amines Using a Catalytic Alkyl Acetal to Form a Transient Directing Group.

Project description:C-H Functionalization of amines is a prominent challenge due to the strong complexation of amines to transition metal catalysts, and therefore typically requires derivatization at nitrogen with a directing group. Transient directing groups (TDGs) permit C-H functionalization in a single operation, without needing these additional steps for directing group installation and removal. Here we report a palladium catalyzed γ-C-H arylation of amines using catalytic amounts of alkyl acetals as transient activators (e.g. commercially available (2,2-dimethoxyethoxy)benzene). This simple additive enables arylation of amines with a wide range of aryl iodides. Key structural features of the novel TDG are examined, demonstrating an important role for the masked carbonyl and ether functionalities. Detailed kinetic (RPKA) and mechanistic investigations determine the order in all reagents, and identify cyclopalladation as the turnover limiting step. Finally, the discovery of an unprecedented off-cycle free-amine directed ϵ-cyclopalladation of the arylation product is reported.

| S-EPMC6391947 | biostudies-literature

Palladium-catalyzed, aminoquinoline-directed arylation of phosphonamidate and phosphinic amide sp3 C-H bonds.

Project description:Aminoquinoline-directed, palladium-catalyzed sp3 C-H bond arylation in phosphonamidates and phosphinic amides is reported. The reaction employs Pd(OAc)2 as a catalyst at 10 mol% loading and cesium phosphate or potassium carbonate as a base in 1,2-dichlorobenzene as a solvent. The directing group can be removed under basic conditions to afford phosphonic acid esters. The chemistry described here is the first example of unactivated sp3 C-H bond arylation by using a phosphorus-containing directing group.

| S-EPMC5479433 | biostudies-literature

Palladium(II)-Catalyzed Regioselective Ortho Arylation of sp(2) C-H Bonds of N-Aryl-2-amino Pyridine Derivatives.

Project description:The direct arylation of N-(2-pyridyl) substituted anilines is described. Arylation takes place in ortho position to the amine functionality and is directed by the pyridine N-substituent. Remarkably, N-arylation was never observed as a competing process even though conditions also suitable for Buchwald-Hartwig reactions were applied. The scope of the reaction was investigated in terms of aryl donors as well as the electronic nature of the substrate. Good yields were obtained for most examples through an operationally simple procedure, which did not require inert conditions or even glove box techniques. Pd(OAc)(2) was applied as a cheap catalyst and boronic acids as readily available aryl donors. To obtain full conversion, 1,4-benzoquinone and a silver salt (e.g., Ag(2)O) were required as additives and reacted at relatively mild temperatures (e.g., 80 °C). Additionally, the pyridine-directing group was cleaved after the reaction to give ortho-arylated aniline derivatives.

| S-EPMC3483625 | biostudies-literature

PdII -Catalyzed Enantioselective C(sp3 )-H Arylation of Cyclobutyl Ketones Using a Chiral Transient Directing Group.

Project description:The use of chiral transient directing groups (TDGs) is a promising approach for developing PdII -catalyzed enantioselective C(sp3 )-H activation reactions. However, this strategy is challenging because the stereogenic center on the TDG is often far from the C-H bond, and both TDG covalently attached to the substrate and free TDG are capable of coordinating to PdII centers, which can result in a mixture of reactive complexes. We report a PdII -catalyzed enantioselective β-C(sp3 )-H arylation reaction of aliphatic ketones using a chiral TDG. A chiral trisubstituted cyclobutane was efficiently synthesized from a mono-substituted cyclobutane through sequential C-H arylation reactions, thus demonstrating the utility of this method for accessing structurally complex products from simple starting materials. The use of an electron-deficient pyridone ligand is crucial for the observed enantioselectivity. Interestingly, employing different silver salts can reverse the enantioselectivity.

| S-EPMC7269848 | biostudies-literature

Palladium(II)-Catalyzed Selective Arylation of Tertiary C-H Bonds of Cyclobutylmethyl Ketones Using Transient Directing Groups.

Project description:We report the first example of selective PdII -catalyzed tertiary C-H activation of cyclobutylmethyl ketones using a transient directing group. An electron-deficient 2-pyridone ligand was identified as the optimal external ligand to enable tertiary C-H activation. A variety of cyclobutylmethyl ketones bearing quaternary carbon centers was readily accessed without preinstalling internal directing groups in up to 81 % yield and >95 : 5 regioisomeric ratios of tertiary C-H arylation to β-methylene (β-methyl) or γ-C-H arylation.

| S-EPMC9084898 | biostudies-literature

Palladium-catalyzed C-H functionalization using guanidine as a directing group: ortho arylation and olefination of arylguanidines.

Project description:Palladium-catalyzed C-H functionalization using guanidine as the directing group was achieved under mild reaction conditions. Various guanidine derivatives were produced in moderate to good yields by using simple unactivated arenes or ethyl acrylate as the source of arylation or olefination, respectively.

| S-EPMC3786205 | biostudies-literature

Methylene C(sp3)-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

Synthesis of (diarylmethyl)amines using Ni-catalyzed arylation of C(sp3)-H bonds.

Project description:The first nickel catalyzed deprotonative cross coupling between C(sp3)-H bonds and aryl chlorides is reported, allowing the challenging arylation of benzylimines in the absence of directing group or stoichiometric metal activation. This methodology represents a convenient access to the (diarylmethyl)amine moiety, which is widespread in pharmaceutically relevant compounds.

| S-EPMC4786957 | biostudies-literature

Palladium-catalyzed benzylic C(sp3)-H carbonylative arylation of azaarylmethyl amines with aryl bromides.

Project description:A highly selective palladium-catalyzed carbonylative arylation of weakly acidic benzylic C(sp3)-H bonds of azaarylmethylamines with aryl bromides under 1 atm of CO gas has been achieved. This work represents the first examples of use of such weakly acidic pronucleophiles in this class of transformations. In the presence of a NIXANTPHOS-based palladium catalyst, this one-pot cascade process allows a range of azaarylmethylamines containing pyridyl, quinolinyl and pyrimidyl moieties and acyclic and cyclic amines to undergo efficient reactions with aryl bromides and CO to provide α-amino aryl-azaarylmethyl ketones in moderate to high yields with a broad substrate scope and good tolerance of functional groups. This reaction proceeds via in situ reversible deprotonation of the benzylic C-H bonds to give the active carbanions, thereby avoiding prefunctionalized organometallic reagents and generation of additional waste. Importantly, the operational simplicity, scalability and diversity of the products highlight the potential applicability of this protocol.

| S-EPMC8372623 | biostudies-literature

Palladium-Catalyzed Highly Regioselective C-3 Arylation of Imidazo[1,5-a]pyridine.

Project description:A direct palladium-catalyzed highly regioselective C-3 arylation of imidazo[1,5-a]pyridine with aryl bromides has been developed. This reaction is quite general with respect to the aryl or hetaryl bromide.

| S-EPMC3855034 | biostudies-literature