Browse
Submit Data
Databases
API
Help

Dataset Information

39 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Photocontrolled Cobalt Catalysis for Selective Hydroboration of ?,?-Unsaturated Ketones.

ABSTRACT: Selectivity between 1,2 and 1,4 addition of a nucleophile to an ?,?-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their "hard" or "soft" character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic hydroboration of ?,?-unsaturated ketones. This includes direct access to previously elusive cyclic enolborates, via 1,4-selective hydroboration, providing a straightforward and stereoselective route to rare syn-aldol products in one-pot. DFT calculations and mechanistic experiments confirm two different mechanisms are operative, underpinning this unusual photocontrolled selectivity switch.

SUBMITTER: Beltran F

PROVIDER: S-EPMC7692884 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Photocontrolled Cobalt Catalysis for Selective Hydroboration of α,β-Unsaturated Ketones.

Beltran Frédéric F Bergamaschi Enrico E Funes-Ardoiz Ignacio I Teskey Christopher J CJ

Angewandte Chemie (International ed. in English) 20200911 47

Selectivity between 1,2 and 1,4 addition of a nucleophile to an α,β-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their "hard" or "soft" character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic ...[more]

PMID: 32767728

Similar Datasets

Cobalt-mediated [3 + 2]-annulation reaction of alkenes with alpha,beta-unsaturated ketones and imines.

Project description:The utility of cobalt dinitrosyl complexes for the [3 + 2] annulation of alkenes with unsaturated enones and ketimines has been demonstrated. Reaction of a series of cobalt dinitrosyl/alkene adducts with conjugate acceptors in the presence of Sc(OTf)(3)/LHMDS formed two new C-C bonds at the carbons alpha to the nitrosyl groups of the substrate, leading to unusual tri- and tetracycles. Retrocycloaddition of these products in the presence of norbornadiene yielded functionalized tetrasubstituted bicyclic olefins.

| S-EPMC2736344 | biostudies-literature

Selective hydroboration of unsaturated bonds by an easily accessible heterotopic cobalt catalyst.

Project description:Homogeneous earth-abundant metal catalysis based on well-defined molecular complexes has achieved great advance in synthetic methodologies. However, sophisticated ligand, hazardous activator and multistep synthesis starting from base metal salts are generally required for the generation of active molecular catalysts, which may hinder their broad application in large scale organic synthesis. Therefore, the development of metal cluster catalysts formed in situ from simple earth-abundant metal salts is of importance for the practical utilization of base metal resource, yet it is still in its infancy. Herein, a mixture of catalytic amounts of cobalt (II) iodide and potassium tert-butoxide is discovered to be highly active for selective hydroboration of vinylarenes and dihydroboration of nitriles, affording a good yield of diversified hydroboration products that without isolation can readily undergo further one pot transformations. It should be highlighted that the alkoxide-pinacolborane combination acts as an efficient activation strategy to activate cobalt (II) iodide for the generation of metastable heterotopic cobalt catalysts in situ, which is proposed to be catalytically active species.

| S-EPMC8217234 | biostudies-literature

Preparation of α-Perfluoroalkyl Ketones from α,β-Unsaturated Ketones via Formal Hydroperfluoroalkylation.

Project description:Formal hydroperfluoroalkylation of enones is achieved in a two-step process comprising conjugate hydroboration and subsequent radical perfluoroalkylation. The 1,4-hydroboration of the enone is conducted in the absence of any transition metal catalyst with catecholborane in 1,2-dichloroethane, and the generated boron enolate is in situ α-perfluoroalkylated with a perfluoroalkyl iodide upon blue LED irradiation in the presence of an amine additive. Both reactions proceed under very mild conditions at room temperature.

| S-EPMC7901661 | biostudies-literature

Catalytic enantioselective peroxidation of alpha,beta-unsaturated ketones.

Project description:Despite the potential of chiral peroxides as biologically interesting or even clinically important compounds, no catalytic enantioselective peroxidation has been reported. With a chiral catalyst not only to induce enantioselectivity but also to convert a well established epoxidation pathway into a peroxidation pathway, the first efficient catalytic peroxidation has been successfully developed. Employing readily available alpha,beta-unsaturated ketones and hydroperoxides and an easily accessible cinchona alkaloid catalyst, this novel reaction will open new possibilities in the asymmetric synthesis of chiral peroxides. Under different conditions a highly enantioselective epoxidation with the same starting materials, reagents, and catalyst has was also established.

| S-EPMC2652727 | biostudies-literature

CuH-catalyzed enantioselective 1,2-reductions of alpha,beta-unsaturated ketones.

Project description:The first study on a general technology for arriving at valued nonracemic allylic alcohols using asymmetric ligand-accelerated catalysis by copper hydride is described.

| S-EPMC3365512 | biostudies-literature

Catalytic asymmetric addition of diphenylzinc to cyclic alpha,beta-unsaturated ketones.

Project description:We have examined the use of our bis(sulfonamide) diol ligand (1) in the asymmetric addition of phenyl groups to cyclic alpha,beta-unsaturated ketones. Good to excellent enantioselectivities have been obtained with cyclic enones bearing alkyl substituents in the 2 position (71-97% enantiomeric excess). Furthermore, excellent enantioselectivities have been observed in the asymmetric phenylation of cyclic enones with 2-iodo and 2-bromo substituents. The results of this study broaden the scope of the asymmetric additions to ketones promoted by the titanium catalyst derived from ligand 1.

| S-EPMC397398 | biostudies-literature

Origin of stereoselectivity in the imidazolidinone-catalyzed reductions of cyclic alpha,beta-unsaturated ketones.

Project description:The organocatalytic transfer hydrogenation reactions of 3-phenyl-2-cyclopentenone with imidazolidinone catalysts are evaluated using the hybrid density functional (B3LYP/6-31G(d)) theory. The origin of the preference for the (E) iminium transition state is determined, and the stereoselectivity of hydride transfer is investigated.

| S-EPMC2751814 | biostudies-literature

Iodine-Mediated Oxidative Rearrangement of α,β-Unsaturated Diaryl Ketones: A Facile Access to 1,2-Diaryl Diketones.

Project description:A metal-free oxidative rearrangement was explored for the synthesis of 1,2-diaryl diketones by utilizing α,β-unsaturated diaryl ketones and I2/TBHP in good to high yields. The reaction proceeds via oxidative aryl migration, followed by C-C bond cleavage. A simple and high-yielding protocol was developed for the synthesis of a wide range of 1,2-diaryl diketones, which are the backbone for a variety of medicinally important molecules.

| S-EPMC6648810 | biostudies-literature

Alternative pathways to α,β-unsaturated ketones via direct oxidative coupling transformation using Sr-doped LaCoO3 perovskite catalyst.

Project description:A strontium-doped lanthanum cobaltite perovskite material was prepared, and used as a recyclable and effective heterogeneous catalyst for the direct oxidative coupling of alkenes with aromatic aldehydes to produce α,β-unsaturated ketones. The reaction afforded high yields in the presence of di-tert-butylperoxide as oxidant. Single oxides or salts of strontium, lanthanum and cobalt, and the undoped perovskite offered a lower catalytic activity than the strontium-doped perovskite. Benzaldehyde could be replaced by benzyl alcohol, dibenzyl ether, 2-oxo-2-phenylacetaldehyde, 2-bromoacetophenone or (dimethoxymethyl) benzene in the oxidative coupling reaction with alkenes. To our best knowledge, reactions between these starting materials with alkenes are new and unknown in the literature.

| S-EPMC6894578 | biostudies-literature

Anionic four-electron donor-based palladacycles as catalysts for addition reactions of arylboronic acids with alpha,beta-unsaturated ketones, aldehydes, and alpha-ketoesters.

Project description:Anionic four-electron donor-based palladacycle-catalyzed 1,4-additions of arylboronic acids with alpha,beta-unsaturated ketones and 1,2-additions of arylboronic acids with aldehydes and alpha-ketoesters are described. Our study demonstrated that palladacycles were highly efficient, practical catalysts for these addition reactions. The work described here not only opened a new paradigm for the application of palladacycles, but may also pave the road for other metalacycles as practically useful catalysts for such addition reactions including asymmetric ones. [reaction: see text].

| S-EPMC2597418 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

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