Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Iron-Catalyzed Coupling of Alkenes and Enones: Sakurai-Michael-type Conjugate Addition of Catalytic Allyliron Nucleophiles.

ABSTRACT: The iron-catalyzed coupling of alkenes and enones through allylic C(sp³)-H functionalization is reported. This redox-neutral process employs a cyclopentadienyliron(II) dicarbonyl catalyst and simple alkene substrates to generate catalytic allyliron intermediates for 1,4-addition to chalcones and other conjugated enones. The use of 2,4,6-collidine as the base and a combination of triisopropylsilyl triflate and LiNTf₂ as Lewis acids was found to facilitate this transformation under mild, functional group-tolerant conditions. Both electronically unactivated alkenes as well as allylbenzene derivatives could be employed as pronucleophilic coupling partners, as could a range of enones bearing electronically varied substituents.

SUBMITTER: Scrivener SG

PROVIDER: S-EPMC10006348 | biostudies-literature | 2023 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Iron-Catalyzed Coupling of Alkenes and Enones: Sakurai-Michael-type Conjugate Addition of Catalytic Allyliron Nucleophiles.

Scrivener Sarah G SG Wang Yidong Y Wang Yi-Ming YM

Organic letters 20230227 9

The iron-catalyzed coupling of alkenes and enones through allylic C(sp<sup>3</sup>)-H functionalization is reported. This redox-neutral process employs a cyclopentadienyliron(II) dicarbonyl catalyst and simple alkene substrates to generate catalytic allyliron intermediates for 1,4-addition to chalcones and other conjugated enones. The use of 2,4,6-collidine as the base and a combination of triisopropylsilyl triflate and LiNTf<sub>2</sub> as Lewis acids was found to facilitate this transformation ...[more]

PMID: 36847432

Similar Datasets

Nickel-catalyzed reductive conjugate addition to enones via allylnickel intermediates.

Project description:An alternative method to copper-catalyzed conjugate addition followed by enolate silylation for the synthesis of β-disubstituted silyl enol ether products (R(1)(R(2))HCCH═C(OSiR(4)(3))R(3)) is presented. This method uses haloarenes instead of nucleophilic aryl reagents. Nickel ligated to either neocuproine or bipyridine couples an α,β-unsaturated ketone or aldehyde (R(2)HC═CHC(O)R(3)) with an organic halide (R(1)-X) in the presence of a trialkylchlorosilane reagent (Cl-SiR(4)(3)). Reactions are assembled on the benchtop and tolerate a variety of functional groups (aldehyde, ketone, nitrile, sulfone, pentafluorosulfur, and N-aryltrifluoroacetamide), electron-rich iodoarenes, and electron-poor haloarenes. Mechanistic studies have confirmed the first example of a catalytic reductive conjugate addition of organic halides that proceeds via an allylnickel intermediate. Selectivity is attributed to (1) rapid, selective reaction of LNi(0) with chlorotriethylsilane and enone in the presence of other organic electrophiles, and (2) minimization of enone dimerization by ligand steric effects.

| S-EPMC3547151 | biostudies-literature

Squaramide-catalyzed enantioselective Michael addition of masked acyl cyanides to substituted enones.

Project description:Masked acyl cyanide (MAC) reagents are shown to be effective umpolung synthons for enantioselective Michael addition to substituted enones. The reactions are catalyzed by chiral squaramides and afford adducts in high yields (90-99%) and with excellent enantioselectivities (85-98%). The addition products are unmasked to produce dicyanohydrins that, upon treatment with a variety of nucleophiles, provide γ-keto acids, esters, and amides. The use of this umpolung synthon has enabled, in enantiomerically enriched form, the first total synthesis of the prenylated phenol (+)-fornicin C.

| S-EPMC3968543 | biostudies-literature

Scandium(III)-Enlarged Salen Complex-Catalyzed Asymmetric Michael Addition of Indoles to Enones.

Project description:Salens are a class of important ligands and have been widely applied in asymmetric catalytic organic reactions. Enlarged salen-like ligands containing flexible chains were synthesized from L-phenylalanine, ethane/propanediamines, and salicylaldehydes, and successfully utilized in the scandium-catalyzed enantioselective Michael addition of indoles and enones (2-cinnamoylpyridine 1-oxides). The catalytic system demonstrates excellent reactivity and stereoselective control over electron-rich indole substrates with up to 99% yield and 99% enantiomeric excess. The enlarged Salen ligands with flexible and rigid combined linkers fit their coordination with large rare earth elements. Their coordination abilities were tuned by the electronic effect of substituents on their salicylaldehyde moiety, facilitating the construction of excellent chiral environments in the scandium(III)-catalyzed asymmetric Michael addition of indoles to 2-cinnamoylpyridine 1-oxides.

| S-EPMC11820277 | biostudies-literature

Synthesis of Quaternary Carbon Stereogenic Centers by Diastereoselective Conjugate Addition of Boron-Stabilized Allylic Nucleophiles to Enones.

Project description:A method for the site-selective and diastereoselective conjugate addition of boron-stabilized allylic nucleophiles to α,β-unsaturated ketones is disclosed. Transformations involve easily prepared γ,γ-disubstituted allyldiboron reagents and proceed in the presence of a fluoride activator at 80 °C. Reactions proceed with a wide variety of enones and allyldiboron reagents efficiently to deliver ketone products that contain otherwise difficult-to-access vicinal β-tertiary and γ-quaternary carbon stereogenic centers and an alkenylboron moiety. The utility of the method is highlighted by several transformations, including cross-coupling and carbocyclizations.

| S-EPMC7289652 | biostudies-literature

Palladium-catalyzed enantioselective addition of two distinct nucleophiles across alkenes capable of quinone methide formation.

Project description:A sequential intramolecular-intermolecular enantioselective alkene difunctionalization reaction has been developed which is thought to proceed through Pd-catalyzed quinone methide formation. The synthesis of new chiral heterocyclic compounds with adjacent chiral centers is achieved in enantiomeric ratios up to 99:1 and diastereomeric ratios up to 10:1.

| S-EPMC2792916 | biostudies-literature

Enantioselective direct Michael addition of cyanohydrin ether derivatives to enones catalyzed by chiral bis(guanidino)iminophosphorane organosuperbase.

Project description:The direct use of cyanohydrin ether derivatives as less acidic pronucleophiles was achieved for the first time in the catalytic enantioselective Michael addition reaction under transition metal free conditions. Chiral bis(guanidino)iminophosphoranes as the higher order organosuperbase facilitated the intended catalytic Michael addition to enones, giving rise to the corresponding products in high yields with moderate to high diastereo- and enantioselectivities in most cases. Further elaboration of the corresponding enantioenriched product was conducted by derivatization into a lactam derivative through hydrolysis followed by cyclo-condensation.

| S-EPMC10034111 | biostudies-literature

Enantioselective Michael Addition of Cyclic β-Diones to α,β-Unsaturated Enones Catalyzed by Quinine-Based Organocatalysts.

Project description:An enantioselective (52-98% ee) Michael addition between cyclic β-diones and α,β-unsaturated enones was established in the presence of quinine-based primary amine or squaramide. A variety of cinnamones were smoothly converted into the desired 3,4-dihydropyrans in moderate to high yields (63-99%). Chalcones were also suitable acceptors and gave rise to the expected adducts in satisfactory yields (31-99%). The resulting adducts readily underwent further modification to form fused 4H-pyran or 2,3-dihydrofuran.

| S-EPMC6152274 | biostudies-literature

Conjugate addition of lithiated methyl pyridines to enones.

Project description:Preparatively useful conjugate addition of lithiated methyl pyridines to cyclic and acyclic enones is reported. Addition of 2-picoline to 3-penten-2-one led to a concise synthesis of the alkaloids (+/-)-senepodine G and (+/-)-cermizine C.

| S-EPMC2921646 | biostudies-literature

Nickel-Catalyzed Reductive Conjugate Addition of Primary Alkyl Bromides to Enones To Form Silyl Enol Ethers.

Project description:Conjugate addition of organometallic reagents to enones to form silyl enol ether products is a versatile method to difunctionalize activated olefins, but the organometallic reagents required can be limiting. The reductive cross-electrophile coupling of unhindered primary alkyl bromides with enones and chlorosilanes to form silyl enol ether products is catalyzed by a nickel-complexed ortho-brominated terpyridine ligand. The conditions are compatible with a variety of cyclic/acyclic enones and functional groups.

| S-EPMC5260806 | biostudies-literature

Reversal of Enantioselectivity in the Conjugate Addition Reaction of Cyclic Enones with the CuOTf/Azolium Catalytic System.

Project description:Hydroxyamide-functionalized azolium salt (NHC•HI 4) was evaluated for dual enantioselective control in a Cu-catalyzed asymmetric conjugate addition (ACA) reaction. This investigation was based on our previously reported ACA reaction catalyzed using CuOTf combined with NHC•AgI complex 1. It was revealed that the stereocontrol of the catalytic ACA reaction depended on the order of the addition of the substrates. Additionally, the chiral NHC ligand precursors, substrates, the relationship between the catalyst ee (eecat) and product ee (eepro), and halogen counter anion were completely evaluated. These results suggested that the catalytic performance of the CuOTf/4 system was comparable with that of the CuOTf/1 system. Furthermore, to gain knowledge of the Cu species generated using CuOTf and NHC ligand precursor, the reaction of CuOTf with 1 was investigated. Although obtaining the corresponding NHC•CuX species failed, the corresponding NHC•AuCl complex 11 could be synthesized by allowing 1 to react with AuCl•SMe2.

| S-EPMC8200092 | 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