Browse
Submit Data
Databases
API
Help

Dataset Information

10 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Development of a Strategy for Linear-Selective Cu-Catalyzed Reductive Coupling of Ketones and Allenes for the Synthesis of Chiral ?-Hydroxyaldehyde Equivalents.

ABSTRACT: We report the development of a stereoselective method for the allylation of ketones utilizing N-substituted allyl equivalents generated from a chiral allenamide. By choice of the appropriate ligand for the Cu-catalyst, high linear selectivity can be obtained with good diastereocontrol. This methodology allows access to chiral ?-hydroxyaldehyde equivalents that were applied in the synthesis of chiral ?-lactones and 2,5-disubstitued tetrahydrofurans.

SUBMITTER: Klake RK

PROVIDER: S-EPMC6781103 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Development of a Strategy for Linear-Selective Cu-Catalyzed Reductive Coupling of Ketones and Allenes for the Synthesis of Chiral γ-Hydroxyaldehyde Equivalents.

Klake Raphael K RK Gargaro Samantha L SL Gentry Skyler L SL Elele Sharon O SO Sieber Joshua D JD

Organic letters 20190918 19

We report the development of a stereoselective method for the allylation of ketones utilizing <i>N</i>-substituted allyl equivalents generated from a chiral allenamide. By choice of the appropriate ligand for the Cu-catalyst, high linear selectivity can be obtained with good diastereocontrol. This methodology allows access to chiral γ-hydroxyaldehyde equivalents that were applied in the synthesis of chiral γ-lactones and 2,5-disubstitued tetrahydrofurans. ...[more]

PMID: 31532684

Similar Datasets

Access to a Catalytically Generated Umpolung Reagent through the Use of Cu-Catalyzed Reductive Coupling of Ketones and Allenes for the Synthesis of Chiral Vicinal Aminoalcohol Synthons.

Project description:We report the development of a stereoselective method for the allylation of ketones utilizing N-substituted allyl equivalents generated from a chiral allenamide. By employing N-heterocyclic carbenes as ligands for the Cu catalyst, good branched selectivity can be obtained with high diastereocontrol. This methodology allows access to a catalytically generated, polarity-reversed (umpolung) allyl nucleophile to enable the preparation of chiral 1,2-aminoalcohol synthons containing a dissonant functional group relationship.

| S-EPMC6902281 | biostudies-literature

Access to Chiral Diamine Derivatives through Stereoselective Cu-Catalyzed Reductive Coupling of Imines and Allenamides.

Project description:Chiral 1,2-diamino compounds are important building blocks in organic chemistry for biological applications and as asymmetric inducers in stereoselective synthesis that are challenging to prepare in a straightforward and stereoselective manner. Herein, we disclose a cost-effective and readily available Cu-catalyzed system for the reductive coupling of a chiral allenamide with N-alkyl substituted aldimines to access chiral 1,2-diamino synthons as single stereoisomers in high yields. The method shows broad reaction scope and high diastereoselectivity and can be easily scaled using standard Schlenk techniques. Mechanistic investigations by density functional theory calculations identified the mechanism and origin of stereoselectivity. In particular, the addition to the imine was shown to be reversible, which has implications toward development of catalyst-controlled stereoselective variants of the identified reductive coupling of imines and allenamides.

| S-EPMC8025098 | biostudies-literature

Enantioselective and site-specific copper-catalyzed reductive allyl-allyl cross-coupling of allenes.

Project description:A copper-catalyzed asymmetric reductive allyl-allyl cross-coupling reaction of allenes with allylic phosphates wherein allenes were used as allylmetal surrogates has been achieved for the first time. This protocol provides an efficient and straightforward route to optically active 1,5-dienes in a highly enantioselective and site-specific fashion. Furthermore, all-carbon quaternary stereogenic centers could also be constructed with this protocol. The versatility of the products is demonstrated through a diverse array of further transformations of the enantioenriched 1,5-dienes.

| S-EPMC6369434 | biostudies-literature

2-Azadienes as Reagents for Preparing Chiral Amines: Synthesis of 1,2-Amino Tertiary Alcohols by Cu-Catalyzed Enantioselective Reductive Couplings with Ketones.

Project description:We introduce a new strategy for synthesis of chiral amines: couplings of ?-aminoalkyl nucleophiles generated by enantioselective migratory insertion of 2-azadienes to a Cu-H. In this report, we demonstrate its application in catalytic reductive coupling of 2-azadienes and ketones to furnish 1,2-amino tertiary alcohols with vicinal stereogenic centers.

| S-EPMC5936605 | biostudies-literature

Conversion of Aldehydes to Branched or Linear Ketones via Regiodivergent Rhodium-Catalyzed Vinyl Bromide Reductive Coupling-Redox Isomerization Mediated by Formate.

Project description:A regiodivergent catalytic method for direct conversion of aldehydes to branched or linear alkyl ketones is described. Rhodium complexes modified by P tBu2Me catalyze formate-mediated aldehyde-vinyl bromide reductive coupling-redox isomerization to form branched ketones. Use of the less strongly coordinating ligand, PPh3, promotes vinyl- to allylrhodium isomerization en route to linear ketones. This method bypasses the 3-step sequence often used to convert aldehydes to ketones involving the addition of pre-metalated reagents to Weinreb or morpholine amides.

| S-EPMC6602061 | biostudies-literature

Cu-Catalyzed Diastereo- and Enantioselective Reactions of γ,γ-Disubstituted Allyldiboron Compounds with Ketones.

Project description:A catalytic diastereo- and enantioselective method for the preparation of complex tertiary homoallylic alcohols containing a vicinal quaternary carbon stereogenic center and a versatile alkenylboronic ester is disclosed. Transformations are promoted by 5 mol % of a readily available copper catalyst bearing a bulky monodentate phosphoramidite ligand, which is essential for attaining both high dr and er. Reactions proceed with a wide variety of ketones and allylic 1,1-diboronate reagents, which enables the efficient preparation of diverse array of molecular scaffolds.

| S-EPMC7230022 | biostudies-literature

Ruthenium catalyzed reductive coupling of paraformaldehyde to trifluoromethyl allenes: CF3-bearing all-carbon quaternary centers.

Project description:Trifluoromethyl substituted allenes engage in ruthenium catalyzed reductive couplings with paraformaldehyde to form products of hydrohydroxymethylation as single regioisomers. This method enables generation of CF3-bearing all-carbon quaternary stereocenters.

| S-EPMC3779475 | biostudies-literature

Enantioselective synthesis of γ-chiral amides via copper-catalyzed reductive relay hydroaminocarbonylation.

Project description:Chiral amides are common and effective structural motifs found in many pharmaceuticals and biologically active molecules. Despite their importance, existing synthetic methods are predominantly employed for the synthesis of α-amides and β-amides. The synthesis of remote chiral amides, characterized by distal stereocenters, typically requires intricate synthetic steps conducted under demanding conditions. Here, we present a general procedure for the copper-catalyzed enantioselective synthesis of γ-chiral amides, employing a reductive relay hydroaminocarbonylation strategy with trisubstituted allylic benzoates and hydroxylamine electrophiles. This approach demonstrates a wide substrate scope with excellent enantioselectivity and regioselectivity, thus providing access to challenging enantioenriched γ-chiral amides.

| S-EPMC11306323 | biostudies-literature

Reductive Coupling of Acrylates with Ketones and Ketimines by a Nickel-Catalyzed Transfer-Hydrogenative Strategy.

Project description:Nickel-catalyzed coupling of benzyl acrylates with activated ketones and imines provides γ-butyrolactones and lactams, respectively. The benzyl alcohol byproduct released during the lactonization/lactamization event is relayed to the next cycle where it serves as the reductant for C-C bond formation. This strategy represents a conceptually unique approach to transfer-hydrogenative C-C bond formation, thus providing examples of reductive heterocyclizations where hydrogen embedded within an alcohol leaving group facilitates turnover.

| S-EPMC5656909 | biostudies-literature

Boron-Catalyzed, Diastereo- and Enantioselective Allylation of Ketones with Allenes

Project description:The diastereo- and enantioselective allylation of ketones

| S-EPMC9442582 | biostudies-literature