Α-arylation Of Ketones Research Articles

Catalytic Formation of α-Aryl Ketones by C-H Functionalization with Cyclic Alkenyl Carbonates and One-Pot Synthesis of Isocoumarins.

We report here a method for direct catalytic introduction of simple α-acylalkyl groups via rhodium-catalyzed C-H functionalization with cyclic alkenyl carbonates, synthetic equivalents to enolates bearing leaving groups. The reaction proceeded smoothly without using bases to give α-aryl ketones in high yields. Various nitrogen-containing aromatic rings and amide groups serve as directing groups. 3-Substituted isocoumarins can also be prepared by one-pot C-H functionalization/cyclization.

Transition-Metal-Free α-Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process.

The α-arylation of enolizable aryl ketones can be carried out with aryl halides under transition-metal-free conditions using KOtBu in DMF. The α-aryl ketones thus obtained can be used for step- and cost-economic syntheses of fused heterocycles and Tamoxifen. Mechanistic studies demonstrate the synergetic role of base and solvent for the initiation of the radical process.

ChemInform Abstract: A Convenient Catalytic Oxidative 1,2‐Shift of Arylalkenes for Preparation of α‐Aryl Ketones Mediated by NaI.

ChemInformVolume 46, Issue 28 Preparative Organic Chemistry ChemInform Abstract: A Convenient Catalytic Oxidative 1,2-Shift of Arylalkenes for Preparation of α-Aryl Ketones Mediated by NaI. Min Zhu, Min Zhu Coll. Biol. Environ. Sci., Zhejiang Shuren Univ., Hangzhou 310015, Peop. Rep. ChinaSearch for more papers by this authorYang Zhao, Yang Zhao Coll. Biol. Environ. Sci., Zhejiang Shuren Univ., Hangzhou 310015, Peop. Rep. ChinaSearch for more papers by this author Min Zhu, Min Zhu Coll. Biol. Environ. Sci., Zhejiang Shuren Univ., Hangzhou 310015, Peop. Rep. ChinaSearch for more papers by this authorYang Zhao, Yang Zhao Coll. Biol. Environ. Sci., Zhejiang Shuren Univ., Hangzhou 310015, Peop. Rep. ChinaSearch for more papers by this author First published: 25 June 2015 https://doi.org/10.1002/chin.201528074Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume46, Issue28July, 2015 RelatedInformation

A convenient catalytic oxidative 1,2-shift of arylalkenes for preparation of α-aryl ketones mediated by NaI

Abstract Using a catalytic amount of NaI and a stoichiometric oxidant Oxone@, a convenient procedure has been developed for the catalytic oxidative 1,2-shift of arylalkenes in CH3CN/H2O at room temperature, which provides the corresponding α-aryl ketones in moderate to good yields. In this protocol, sodium iodide is first oxidized into hypoiodous acid, which reacts with arylalkene to afford iodohydrin. Then, the iodohydrin is transformed into the α-aryl ketone via an oxidative 1,2-shift rearrangement.

Catalytic asymmetric synthesis of sterically hindered tertiary α-aryl ketones.

The catalytic asymmetric synthesis of a series of tertiary α-aryl cyclopentanones and cyclohexanones has been accomplished via a Pd-catalyzed decarboxylative protonation of the corresponding α-aryl-β-keto allyl esters. Enantioselectivities of up to 92% ee and 74% ee were achieved for cyclopentanone and cyclohexanone substrates, respectively. The route described gives access to these important structural motifs in moderate to high levels of enantioselectivity. In particular, this is only the second direct approach for the preparation of tertiary α-aryl cyclopentanones. The synthetic approach allows for simple modification of the aryl group. Significantly, substrates containing sterically hindered aryl groups gave the highest levels of enantioselectivity, and these aryl groups were readily installed by a Pb-mediated arylation of a β-keto allyl ester.

A three-step process to facilitate the annulation of polycyclic aromatic hydrocarbons.

A new efficient three-step process to annulate polycyclic aromatic hydrocarbons (PAHs) has been developed, providing access to PAHs with saturated rings that under current chemical methods would be difficult to produce in an efficient manner. This method relies on a palladium-catalyzed cross-coupling reaction of various brominated PAHs with cyclohexanone to yield α-arylated ketones, which are converted to regiospecific vinyl triflates and cyclized by a palladium-catalyzed intramolecular arene-vinyl triflate coupling to produce PAHs with incorporated saturated rings or "tetrahydroindeno-annulated" PAHs.

Substrate-directed hydroacylation: rhodium-catalyzed coupling of vinylphenols and nonchelating aldehydes.

We report a protocol for the hydroacylation of vinylphenols with aryl, alkenyl, and alkyl aldehydes to form branched products with high selectivity. This cross-coupling yields α-aryl ketones that can be cyclized to benzofurans, and it enables access to eupomatenoid natural products in four steps or less from eugenol. Excellent reactivity and high levels of regioselectivity for the formation of the branched products were observed. We propose that aldehyde decarbonylation is avoided by the use of an anionic directing group on the alkene and a diphosphine ligand with a small bite angle.

An expedient route to heterocycles through α-arylation of ketones and arylamides by microwave induced thermal SRN1 reactions

Quick reaction by microwave irradiation promotes nucleophilic substitution by thermally induced electron transfer mechanism and allows to synthesize deoxibenzoin and indol heterocycles derivates by inter or intramolecular ring closure.

Copper-catalyzed coupling of aryl iodides and tert-butyl β-keto esters: efficient access to α-aryl ketones and α-arylacetic acid tert-butyl esters

CuI/trans-4-hydroxy-l-proline catalyzed coupling of aryl iodides with tert-butyl β-keto esters proceeded smoothly at 40 °C in DMF, providing α-aryl ketones after acid-promoted deprotection and decarboxylation of tert-butyl ester group. While CuI/2-picolinic acid catalyzed coupling of aryl iodides with tert-butyl acetoacetate at 70 °C in dioxane delivered α-arylacetic acid tert-butyl esters upon spontaneous deacylation. A wide range of functional groups, such as acetyl, methoxy, nitrile, nitro, bromo, and chloro were compatible with the reaction conditions.

Stereoselective Rearrangements with Chiral Hypervalent Iodine Reagents

I likes rearrangements: Hypervalent iodine compounds can be used as environmentally friendly, mild, and selective reagents for highly enantioselective rearrangements of alkenes. For the first time, rearrangements to α-arylated ketones can be performed enantioselectively using lactic acid-based iodine(III) reagents.

Copper‐Catalyzed Synthesis of α‐Aryl Ketones by Metal–Organic Framework MOF‐199 as an Efficient Heterogeneous Catalyst

AbstractA highly crystalline porous copper‐based metal–organic framework MOF‐199 was synthesized from the reaction of 1,3,5‐benzenetricarboxylic acid and copper nitrate trihydrate by a solvothermal method. The MOF‐199 was characterized by several techniques, including X‐ray powder Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA), Fourier Transform‐Infrared (FT‐IR), Atomic Absorption Spectrophotometry (AAS), and nitrogen physisorption measurements. The MOF‐199 proved to be an efficient catalyst for the C‐arylation of aryl iodides with acetylacetone to form α‐aryl ketones as the principal products. The catalyst can be separated from the reaction mixture by simple decantation, and be reused without significant degradation in catalytic activity. No contribution from homogeneous catalysis of active species leaching into the liquid phase was detected, confirming that the MOF‐199 is a truly heterogeneous catalyst.

ChemInform Abstract: Palladium‐Catalyzed Mono‐α‐arylation of Acetone with Aryl Imidazolylsulfonates.

AbstractAir‐ and moisture‐stable aryl imidazolylsulfonates are established as nongenotoxic, user‐friendly electrophiles for α‐arylation of ketones.

An efficient C–C bond formation reaction for the synthesis of α-arylated ketones under mild conditions

A wide range of substituted α-arylated ketones were synthesized in moderate to excellent yields via a Truce Smiles rearrangement. The main scaffold has various applications in medical and biochemical fields. This process also provides a facile and direct method for the C–C bond formation.

Palladium‐Catalyzed Mono‐α‐Arylation of Acetone with Aryl Imidazolylsulfonates

Air- and moisture-stable aryl imidazolylsulfonates are established as nongenotoxic, user-friendly electrophiles for α-arylation of ketones.

Tandem Decarboxylative Allylation and Fragmentation of Allyl Benzocyclobutenyl Carbonates: Access to ortho-Functionalized Aryls from Aryl Bromides

Allyl benzocyclobutyl carbonates yield ortho-allyl α-aryl ketones through a palladium-catalyzed decarboxylative allylation, fragmentation, and cross-coupling process.

Enantioselective construction of sterically hindered tertiary α-aryl ketones: a catalytic asymmetric synthesis of isoflavanones

A method for the catalytic asymmetric α-arylation of ketones bearing very sterically hindered aryl rings has been developed. This reaction occurs under mild conditions, in short reaction times and has been applied to the first catalytic asymmetric synthesis of isoflavanones.

Synthesis of Benzo-fused Heterocycles by Intramolecular α-Arylation of Ketone Enolate Anions

A two-step synthesis of six-, seven-, eight-, and nine-member benzo-fused heterocycles in good to excellent yields is reported. The synthetic strategy involves the generation of a new intramolecular α-aryl ketone bond by the photostimulated S(RN)1 reaction of ketone enolate anions linked to a pendant haloarene as the key step. On the other hand, an intramolecular C(Ar)-C(Ar) coupling led to the formation of five- and six-member benzo-fused heterocycles (9H-carbazole and phenanthridine) when an aromatic amide anion is competitively formed.

Aryl(chloro)methyl 4-Tolyl Sulfoxides: Synthesis and Application to the Synthesis of α-Aryl Ketones

Aryl(chloro)methyl 4-tolyl sulfoxides were synthesized from arylmethyl 4-tolyl sulfoxides in moderate-to-good yields by sequential treatment with lithium diisopropylamide and tosyl chloride at low temperatures. Treatment of the lithium α-sulfinyl carbanion of the aryl(chloro)methyl 4-tolyl sulfoxides with aldehydes or ketones resulted in the formation of adducts in good-to-high yields. Treatment of these adducts with tert-butylmagnesium chloride gave the corresponding magnesium alkoxides. On treatment with isopropylmagnesium chloride, the alkoxides gave the corresponding magnesium β-oxido carbenoids, which rearranged to give α-aryl ketones in good-to-high yields. The magnesium enolate intermediates generated by rearrangement of the β-oxido carbenoids could also be trapped with electrophiles to give α-aryl α-substituted ketones. These procedures offer a good method for the synthesis of a variety of α-aryl ketones from aldehydes and ketones.

A Colorimetric High‐Throughput Screening Method for Palladium‐Catalyzed Coupling Reactions of Aryl Iodides Using a Gold Nanoparticle‐Based Iodide‐Selective Probe

Catching the couplings: A general and simple screening method for palladium-catalyzed coupling reactions of aryl iodides utilizes gold nanoparticles. This assay was successfully employed in several aminations, α-arylation of ketones, and decarboxylative couplings. 96 samples were screened in a few minutes.

A highly active and selective palladium pincer catalyst for the formation of α-aryl ketones via cross-coupling

Several air and moisture stable Pd(II) pincer complexes were synthesized via oxidative addition of Pd(0) to novel PheBox pincer ligand precursors. Low loadings (1 mol%) of the Pd complex [t-BuPhebox-Me(2)]PdBr are capable of efficiently promoting the selective α-monoarylation of a variety of ketones with numerous aryl bromides in only 1 h at 70 °C with 82-99% yields.