Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Excited-state palladium-catalysed reductive alkylation of imines: scope and mechanism.

ABSTRACT: Palladium catalysis induced by visible-light irradiation is a promising tool for promoting unusual chemical transformations. We describe the development of excited-state palladium-catalyzed reductive alkylation of imines with alkyl bromides. The new methodology shows broad functional group tolerance and can additionally be applied in the direct three-component reaction of aldehydes, anilines, and alkyl bromides to give the alkyl amines under mild reaction conditions. Time-resolved photoluminescence experiments allowed the determination of the excited-state reaction kinetics and indicate that the reaction is proceeding via the inner-sphere electron transfer mechanism.

SUBMITTER: Kancherla R

PROVIDER: S-EPMC9337745 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Excited-state palladium-catalysed reductive alkylation of imines: scope and mechanism.

Kancherla Rajesh R Muralirajan Krishnamoorthy K Rueping Magnus M

Chemical science 20220707 29

Palladium catalysis induced by visible-light irradiation is a promising tool for promoting unusual chemical transformations. We describe the development of excited-state palladium-catalyzed reductive alkylation of imines with alkyl bromides. The new methodology shows broad functional group tolerance and can additionally be applied in the direct three-component reaction of aldehydes, anilines, and alkyl bromides to give the alkyl amines under mild reaction conditions. Time-resolved photoluminesce ...[more]

PMID: 35974758

Similar Datasets

Boric acid catalysed hydrolysis of peroxyacids† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3ra01046e

Project description:This study shows for the first time that boric acid catalyses the hydrolysis of peroxyacids, resulting in an approximately 12-fold increase in hydrolysis rate for both peracetic acid (PAA) and 3-chloroperbenzoic acid (MCPBA) when 0.1 M boric acid is present. The maximum rate of hydrolysis occurs at pH 9 and pH 8.4 for PAA and MCPBA respectively. In contrast, carbonate buffer does not enhance the rate of PAA hydrolysis. The reaction was followed by measuring the initial rate of hydrogen peroxide formation using a specific Ti(iv) complexation method. The study of the hydrolysis reaction requires the presence of 2 × 10−5 M each of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine tetramethylene phosphonic acid (EDTMP) in all solutions in order to chelate metal ions across the full pH range (3 to 13) that would otherwise contribute to peroxyacid decomposition. Catalysis of peroxyacid hydrolysis is most likely effected by the triganol boric acid acting as a Lewis acid catalyst, associating with the peroxide leaving group in the transition state to reduce the leaving group basicity. The products of the reaction are the well characterised monoperoxoborate species and the parent carboxylic acid. Analysis of the pH and borate dependence data reveals that in addition to a catalytic pathway involving a single boric acid molecule, there is a significant pathway involving either (a) two boric acid molecules or (b) the polyborate species, B3O3(OH)4−. Knowledge about catalytic mechanisms for the loss of peroxyacids through hydrolysis is important because they are widely used in reagents in a range of oxidation, bleaching and disinfection applications. Boric acid catalyses the hydrolysis of peroxyacids, with possible pathways involving one and two molecules of boric acid as well as polyborate species.

| S-EPMC10103745 | biostudies-literature

Photoinduced iron-catalyzed C–H alkylation of polyolefins† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3sc03252c

Project description: Not available

| S-EPMC10498505 | biostudies-literature

Alkylboronic acids as alkylating agents: photoredox-catalyzed alkylation reactions assisted by K3PO4† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d2sc05521j

Project description:Despite the ubiquity of alkylboronic acids in organic synthesis, their utility as alkyl radical precursors in visible-light-induced photocatalytic reactions is limited by their high oxidation potentials. In this study, we demonstrated that an inorganophosphorus compound can modulate the oxidation potentials of alkylboronic acids so that they can act as alkyl radical precursors. We propose a mechanism based on the results of fluorescence quenching experiments, electrochemical experiments, 11B and 31P NMR spectroscopy, and other techniques. In addition, we describe a simple and reliable alkylation method that has good functional group tolerance and can be used for direct C–B chlorination, cyanation, vinylation, alkynylation, and allylation, as well as late-stage functionalization of derivatized drug molecules. Notably, alkylboronic acids can be selectively activated in the presence of a boronic pinacol ester. An alkylation method using inorganophosphorus-activated alkylboronic acids to act as alkyl radical precursors has been developed. This method can be used for direct C–B chlorination, cyanation, vinylation, alkynylation, and allylation.

| S-EPMC9683010 | biostudies-literature

Nickel-Catalyzed Reductive Alkylation of Heteroaryl Imines.

Project description:The preparation of heterobenzylic amines by a Ni-catalyzed reductive cross-coupling between heteroaryl imines and C(sp3 ) electrophiles is reported. This umpolung-type alkylation proceeds under mild conditions, avoids the pre-generation of organometallic reagents, and exhibits good functional group tolerance. Mechanistic studies are consistent with the imine substrate acting as a redox-active ligand upon coordination to a low-valent Ni center. The resulting bis(2-imino)heterocycle⋅Ni complexes can engage in alkylation reactions with a variety of C(sp3 ) electrophiles, giving heterobenzylic amine products in good yields.

| S-EPMC9474666 | biostudies-literature

Chlorobenzene-driven palladium-catalysed lactonisation of benzoic acids† † Electronic supplementary information (ESI) available: Experimental procedures and spectral/analytical data. See DOI: https://doi.org/10.1039/d3ra08176a

Project description: Not available

| S-EPMC10759164 | biostudies-literature

The power of microdroplet photochemistry† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d4sc00056k

Project description: Not available

| S-EPMC10915808 | biostudies-literature

Total synthesis of bi-magnolignan† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3ra01121f

Project description:Bi-magnolignan, isolated from the leaves of Magnolia officinalis, has shown excellent physiological activity against tumor cells. An efficient strategy for the first total synthesis of bi-magnolignan is reported. The bi-dibenzofuran skeleton was constructed via functional group interconversions of commercially available materials 1,2,4-trimethoxybenzene and 4-allylanisole. Then, the dibenzofuran skeleton was afforded by subsequent Suzuki coupling and intramolecular dehydration. The total synthesis of natural product was accomplished through FeCl3 catalyzed oxidative coupling. The first total synthesis of bi-magnolignan in eight steps from commercially available starting materials has been developed.

| S-EPMC10018648 | biostudies-literature

The Pd-catalysed asymmetric allylic alkylation reactions of sulfamidate imines.

Project description:The Pd-catalysed asymmetric allylic alkylation (Pd-AAA) of prochiral enamide anions derived from 5H-oxathiazole 2,2-dioxides has been developed. Various 4,5-disubstituted and 4-substituted cyclic sulfamidate imines have participated in the transformation with a range of allyl carbonates-as well as 2-vinyl oxirane, 2-vinyl-N-tosylaziridine, and 2-vinyl-1,1-cyclopropane dicarboxylate-to furnish the desired C-allylated products in moderate to high yields, with high regioselectivites and generally high enantioselectivities. Conversion between N- and C-allyl products was observed, with the N-allylated products converting to the C-allylated products over time. The resulting high-value allylated heterocyclic products all bear a tetrasubstituted stereogenic centre and can be reduced to an allylated chiral sulfamidate or an amino alcohol.

| S-EPMC8494038 | biostudies-literature

Catalytic photochemical enantioselective α-alkylation with pyridinium salts† † Electronic supplementary information (ESI) available: Experimental details, characterization data, and spectral data (PDF). See DOI: https://doi.org/10.1039/d2sc05654b

Project description:We have developed a chiral amine catalyzed enantioselective α-alkylation of aldehydes with amino acid derived pyridinium salts as alkylating reagents. The reaction proceeds in the presence of visible light and in the absence of a photocatalyst via a light activated charge-transfer complex. We apply this photochemical stereoconvergent process to the total synthesis of the lignan natural products (−)-enterolactone and (−)-enterodiol. Mechanistic studies support the ground-state complexation of the reactive components followed by divergent charge-transfer processes involving catalyst-controlled radical chain and in-cage radical combination steps. We have developed a chiral amine catalyzed enantioselective α-alkylation of aldehydes with amino acid derived pyridinium salts as alkylating reagents.

| S-EPMC9847668 | biostudies-literature

Efficient red thermally activated delayed fluorescence emitters achieved through precise control of excited state energy levels† † Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d4sc00535j

Project description: Not available

| S-EPMC11023617 | biostudies-literature