Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Ni-Catalyzed Enantioselective C-Acylation of ?-Substituted Lactams.

ABSTRACT: A new strategy for catalytic enantioselective C-acylation to generate ?-quaternary-substituted lactams is reported. Ni-catalyzed three-component coupling of lactam enolates, benzonitriles, and aryl halides produces ?-imino lactams that then afford ?-keto lactams by acid hydrolysis. Use of a readily available Mandyphos-type ligand and addition of LiBr enable the construction of quaternary stereocenters on ?-substituted lactams to form ?-keto lactams in up to 94% ee.

SUBMITTER: Hayashi M

PROVIDER: S-EPMC4963289 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Ni-Catalyzed Enantioselective C-Acylation of α-Substituted Lactams.

Hayashi Masaki M Bachman Shoshana S Hashimoto Satoshi S Eichman Chad C CC Stoltz Brian M BM

Journal of the American Chemical Society 20160715 29

A new strategy for catalytic enantioselective C-acylation to generate α-quaternary-substituted lactams is reported. Ni-catalyzed three-component coupling of lactam enolates, benzonitriles, and aryl halides produces β-imino lactams that then afford β-keto lactams by acid hydrolysis. Use of a readily available Mandyphos-type ligand and addition of LiBr enable the construction of quaternary stereocenters on α-substituted lactams to form β-keto lactams in up to 94% ee. ...[more]

PMID: 27373124

Similar Datasets

Palladium-Catalyzed Enantioselective Relay Heck Arylation of Enelactams: Accessing ?,?-Unsaturated ?-Lactams.

Project description:In this Communication, we describe the construction of chiral ?,?-unsaturated ?-lactams, widely used as pharmacophores, in high yields and excellent enantioselectivities using an oxidative relay Heck arylation reaction. This strategy also allows facile access to 7-substituted ?,?-unsaturated ?-lactam products and ?-lactams containing a tetrasubstituted nitrogen-bearing stereocenter.

| S-EPMC5993423 | biostudies-other

Enantioselective Synthesis of ?-Lactams by Lewis Base Catalyzed Sulfenoamidation of Alkenes.

Project description:A method for the catalytic, enantioselective, intramolecular 1,2-sulfenoamidation of alkenes is described. Lewis base activation of a suitable sulfur electrophile generates an enantioenriched, thiiranium ion intermediate from a ?,?-unsaturated sulfonyl carboxamide. This intermediate is subsequently intercepted by the sulfonamide nitrogen resulting in cyclization to form ?-lactams. Electron-poor alkenes required the use of a new selenophosphoramidate Lewis base catalyst. Subsequent manipulations of the products harness the latent reactivity of both the amide and thioether functionality.

| S-EPMC7127933 | biostudies-literature

Nickel-catalyzed enantioselective allylic alkylation of lactones and lactams with unactivated allylic alcohols.

Project description:The first nickel-catalyzed enantioselective allylic alkylation of lactone and lactam substrates to deliver products bearing an all-carbon quaternary stereocenter is reported. The reaction, which utilizes a commercially available chiral bisphosphine ligand, proceeds in good yield with a high level of enantioselectivity (up to 90% ee) on a range of unactivated allylic alcohols for both lactone and lactam nucleophiles. The utility of this method is further highlighted via a number of synthetically useful product transformations.

| S-EPMC5912103 | biostudies-other

Detection and Verification of a Key Intermediate in an Enantioselective Peptide Catalyzed Acylation Reaction.

Project description:Until now, the intermediate responsible for the acyl transfer of a highly enantioselective tetrapeptide organocatalyst for the kinetic resolution of trans-cycloalkane-1,2-diols has never been directly observed. It was proposed computationally that a π-methylhistidine moiety is acylated as an intermediate step in the catalytic cycle. In this study we set out to investigate whether we can detect and characterize this key intermediate using NMR-spectroscopy and mass spectrometry. Different mass spectrometric experiments using a nano-ElectroSpray Ionization (ESI) source and tandem MS-techniques allowed the identification of tetrapeptide acylium ions using different acylation reagents. The complexes of trans-cyclohexane-1,2-diols with the tetrapeptide were also detected. Additionally, we were able to detect acylated tetrapeptides in solution using NMR-spectroscopy and monitor the acetylation reaction of a trans-cyclohexane-1,2-diol. These findings are important steps towards the understanding of this highly enantioselective organocatalyst.

| S-EPMC9571696 | biostudies-literature

Ni- and Pd-catalyzed synthesis of substituted and functionalized allylic boronates.

Project description:Two highly efficient and convenient methods for the synthesis of functionalized and substituted allylic boronates are described. In one procedure, readily available allylic acetates are converted to allylic boronates catalyzed by Ni/PCy(3) or Ni/PPh(3) complexes with high levels of stereoselectivity and in good yields. Alternatively, the borylation can be accomplished with commercially available Pd catalysts [e.g., Pd(2)(dba)(3), PdCl(2), Pd/C], starting with easily accessed allylic halides.

| S-EPMC3322416 | biostudies-literature

Nickel-Catalyzed Amidoalkylation Reaction of γ-Hydroxy Lactams: An Access to 3-Substituted Isoindolinones.

Project description:An efficient Ni(ClO4)2·6H2O-promoted amidoalkylation reaction for the synthesis of 3-substituted isoindolinones involving various γ-hydroxy lactams and nucleophiles has been successfully developed. The transformation proceeds with both carbon (ketones and arenes) and heteroatom (alcohols, thiols, and amines) nucleophiles and in both intermolecular and intramolecular manners. The prominent features of the present strategy are wide substrate scope, excellent group tolerability, and moderate to good yields (up to 96% yield). The present strategy is also characterized by remarkable superiority over the current synthetic methods. Furthermore, the reaction could be scaled up to the multigram scale.

| S-EPMC6868882 | biostudies-literature

Copper-Catalyzed Regio- and Enantioselective Hydroboration of Difluoroalkyl-Substituted Internal Alkenes.

Project description:Catalytic asymmetric hydroboration of fluoroalkyl-substituted alkenes is a straightforward approach to access chiral small molecules possessing both fluorine and boron atoms. However, enantioselective hydroboration of fluoroalkyl-substituted alkenes without fluorine elimination has been a long-standing challenge in this field. Herein, a copper-catalyzed hydroboration of difluoroalkyl-substituted internal alkenes with high levels of regio- and enantioselectivities is reported. The native carbonyl directing group, copper hydride system, and bisphosphine ligand play crucial roles in suppressing the undesired fluoride elimination. This atom-economic protocol provides a practical synthetic platform to obtain a wide scope of enantioenriched secondary boronates bearing the difluoromethylene moieties under mild conditions. Synthetic applications including functionalization of biorelevant molecules, versatile functional group interconversions, and preparation of difluoroalkylated Terfenadine derivative are also demonstrated.

| S-EPMC10724385 | biostudies-literature

Enantioselective access to chiral aliphatic amines and alcohols via Ni-catalyzed hydroalkylations.

Project description:Chiral aliphatic amine and alcohol derivatives are ubiquitous in pharmaceuticals, pesticides, natural products and fine chemicals, yet difficult to access due to the challenge to differentiate between the spatially and electronically similar alkyl groups. Herein, we report a nickel-catalyzed enantioselective hydroalkylation of acyl enamines and enol esters with alkyl halides to afford enantioenriched α-branched aliphatic acyl amines and esters in good yields with excellent levels of enantioselectivity. The operationally simple protocol provides a straightforward access to chiral secondary alkyl-substituted amine and secondary alkyl-substituted alcohol derivatives from simple starting materials with great functional group tolerance.

| S-EPMC8119980 | biostudies-literature

Rhodium catalyzed enantioselective cyclization of substituted imidazoles via C-H bond activation.

Project description:The enantioselective intramolecular alkylation of substituted imidazoles with enantiomeric excesses up to 98% has been accomplished by rhodium catalyzed C-H bond functionalization with (S,S',R,R')TangPhos as the chiral ligand.

| S-EPMC2782779 | 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

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