Reaction Of Arylboronic Acids Research Articles

A New Access to 16-Membered Macrocycles: Synthesis of the Model C-O-D Ring System of Vancomycin

A simple methodology for construction of the C-O-D diphenyl ether 16-membered ring system present in vancomycin by an intramolecular O-arylation reaction of arylboronic acid with substituted phenol for formation of the macrocyclic biaryl ether is described.

Introduction of Allyl and Prenyl Side‐Chains into Aromatic Systems by Suzuki Cross‐Coupling Reactions

AbstractThis paper reports some studies aiming at the developement of a general protocol useful for the synthesis of allyl‐ and prenylaromatic compounds. The first part deals with the preparation of boron reagents like arylboronic acids and their pinacol esters as well as of pinacol allyl‐ and prenylboronates. The second part of the paper is devoted to the use of these boron reagents in Suzuki–Miyaura cross‐coupling reactions leading to allylation and prenylation of aromatic compounds. Of the six methods studied, the most promising results were obtained by using the Pd2(dba)3‐catalyzed reactions of arylboronic acids with allyl and prenyl bromides, that lead to the products of cross coupling in high yields (average 87%), and the reactions of aryl trifluoroborates with allyl and prenyl bromides catalyzed by Pd(OAc)2 that lead to the products of coupling in all cases in high yields (average 82%).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Celebrating 20 Years of SYNLETT - Special Account On Palladium(II)-Catalyzed Additions of Arylboronic Acids to Electron-Deficient Alkenes, Aldehydes, Imines, and Nitriles

The enantioselective synthesis of cyclic and acyclic β-aryl ketones, esters, and amides by palladium(II)-catalyzed 1,4-addition of an arylboronic acid or a potassium aryltrifluoroborate to unsaturated carbonyl compounds is described. The protocol provides simple access to biologically and pharmaceutically active compounds such as optically active chromenes, (R)-tolterodine, (R)-CDP 840, and the endothelin receptor antagonist. The palladium(II) catalysts are also efficient for Grignard-type addition of arylboronic acids to carbon-heteroatom double bonds and triple bonds of aldehydes, ketones, aldimines, and nitriles. The catalytic cycle involves transmetalation between arylboronic acid and palladium(II) complexes as the key process, the mechanism of which is discussed on the basis of characterization of the transmetalation intermediates and electronic effects of the substituents. The enantio­selection mechanism and the efficiency of a chiraphos ligand for structurally planar unsaturated ketones are discussed on the basis of the results of DFT computational studies on the modes of coordination of the substrates to the phenylpalladium(II)/(S,S)-chiraphos intermediate. This review focuses mainly on reactions of arylboronic acids; there are very few such reports for other organoboronic acids or esters, but pinacol allylboronate undergoes 1,4-addition to unsaturated N-acylpyrroles.

Carbonylative Suzuki–Miyaura Coupling of Arylboronic Acids with Aryl Iodides Catalyzed by the MCM‐41‐Supported Bidentate Phosphane Palladium(II) Complex

AbstractThe first heterogeneous carbonylative Suzuki–Miyaura cross‐coupling reaction of arylboronic acids with aryl iodides under an atmospheric pressure of carbon monoxide has been achieved in anisole at 80 °C in the presence of a catalytic amount of an MCM‐41‐supported bidentate phosphane palladium(II) complex (MCM‐41‐2P‐PdII), yielding unsymmetrical biaryl ketones in good‐to‐high yields. This polymeric palladium catalyst exhibited higher activity and selectivity than [PdCl2(PPh3)2] and can be reused at least 10 times without any decrease in activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

ChemInform Abstract: Synthesis of Aryl Ketones by Cross‐Coupling Reaction of Arylboronic Acids with Carboxylic Anhydrides in Aqueous Phase.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Palladium-catalyzed cross-coupling reactions of aryl boronic acids with aryl halides in water

An efficient Suzuki cross-coupling reaction using a variety of aryl halides in neat water was developed. The Pd-catalyzed reaction between aryl bromides or chlorides and phenyl bo-ronic acids was compatible with various functional groups and affords biphenyls in good to excellent yields without requirement of organic cosolvents. The air stability and solubility in water of the palladium-phosphinous acid complexes were considered to facilitate operation of the coupling reaction and product isolation. The reaction conditions including Pd catalyst selection, temperature, base and catalyst recoverability were also investigated.

The synthesis and catalytic activity of the iridium(I) hydroquinone complex [(H2Q)Ir(COD)

Abstract The η6-hydroquinone iridium complex [(η6-H2Q)Ir(COD)]BF4 undergoes facile double deprotonation to the η4-quinone anionic analogue. The latter has been shown to be the first example of an iridium complex that catalyzes 1,4 conjugate addition reactions of aryl boronic acids to electron deficient olefins.

Pt-Catalyzed Addition of Arylboronic Acids to Aldehydes and Enals

The 1,2-addition reaction of arylboronic acids and carbonyl compounds is a useful tool for alcohol synthesis, where arylboronic species serve as storable analogues of highly reactive Mg- or Li-organometallic compounds. The presented method has advantages of very low catalyst loading (up to 0.01 mol%) as well as relatively broad substrate scope. The reactions with enones give bis-arylated adducts: 1,3-diaryl-1-propanols.

Synthesis of Aryl Ketones by Cross-Coupling Reaction of Arylboronic Acids with Carboxylic Anhydrides in Aqueous Phase

A highly efficient aqueous system of PdCl2-catalyzed cross-coupling reaction of arylboronic acid with carboxylic anhydride (Suzuki-type reaction) without the use of phosphine ligands was developed. The reactions went smoothly in acetone/H2O phase to give good yields of aryl ketones in short reaction times (1–3 h) at room temperature in air and were unaffected by the presence of electron-releasing and electron-withdrawing substituents in both the arylboronic acids and carboxylic anhydrides.

ChemInform Abstract: Synthesis of Rhodium Colloidal Nano‐Coating Grafted Mesoporous Silica Composite and Its Application as Efficient Environmentally Benign Catalyst for Heck‐Type Reaction of Arylboronic Acids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Potassium permanganate/carboxylic acid/organic solvent: a powerful reagent for enone oxidation and aryl coupling reactions

The α′-acetoxylation of enones and the α-acetoxylation of aromatic ketones were carried out with potassium permanganate and acetic acid, in which acetoxylation products were obtained in 74–96% yields. The same reaction was carried out with carboxylic acids other than acetic acid, which furnished corresponding acyloxy ketones with the same regioselectivity. For the first time, formyloxylation products were synthesized in a 61–85% yield by using formic acid. The potassium permanganate and acetic acid method was also used for aryl coupling reactions. The reaction of arylboronic acids and arylhydrazines in benzene with potassium permanganate and acetic acid in turn furnished biaryls in 85–96% yield. We have shown that potassium permanganate/carboxylic acid/organic solvent behaves as manganese(III) acetate.

Direct Vinylation and Difluorovinylation of Arylboronic Acids Using Vinyl- and 2,2-Difluorovinyl Tosylates via the Suzuki−Miyaura Cross Coupling

General reaction conditions were developed for the Pd(0)-catalyzed Suzuki-Miyaura coupling reaction of aryl boronic acids with a simple electrophilic vinylation reagent, vinyl tosylate, providing access to styrene derivatives in good yields. The easily accessible vinyl tosylate represents a stable and less toxic alternative to the vinyl halides and the triflate/nonaflate derivatives. Furthermore, this methodology was expanded to provide a facile and straightforward approach for the introduction of a gem-difluorovinyl substituent onto an aromatic ring using the similar and also readily available 2,2-difluorovinyl tosylate as the electrophilic complement.

2-Alkylidene-1,3-dithiane Monoxides as Activated Alkenes in Rhodium-Catalyzed Addition Reaction of Arylboronic Acids

2-Methylene-l,3-dithiane 1-oxide reacts with arylboronic acids in the presence of a rhodium catalyst in aqueous dioxane to afford 2-arylmethyl-1,3-dithiane 1-oxides in good yields.

Formation of Boronate Ester Polymers with Efficient Intrastrand Charge‐Transfer Transitions by Three‐Component Reactions

AbstractThe three‐component reaction of aryl boronic acids with 1,2,4,5‐tetrahydroxybenzene and 1,2‐bis(4‐pyridyl)ethylene or 4,4′‐bipyridine leads to the formation of dark‐purple boronate ester polymers. Crystallographic analyses show that the polymer strands have a zig–zag geometry, and the bis(dioxaborole) units are connected by dipyridyl linkers through dative B–N interactions. Upon dissolution of the polymers in hot chloroform, most of the B–N connections are broken, which indicates that polymer formation is a reversible process. A computational study provides evidence that the strong color of the polymers is due to efficient intrastrand charge‐transfer excitations from the tetraoxobenzene to the dipyridyl linker.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The Surfactant‐Promoted Cross‐Coupling Reactions of Arylboronic Acids with Carboxylic Anhydrides or Acyl Chlorides in Water.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Wide bite angle diphosphine rhodium complexes: Synthesis, structure, and catalytic 1,4-addition of arylboronic acids to enones

A rhodium complex [ClRh(CO)( L1)] featuring a wide bite angle diphosphine ligand ( L1 = 1,3-bis(2-diphenylphosphinomethylphenyl)benzene) has been synthesized and structurally characterized. L1 supports a bite angle (P–M–P angle, β) of 171.4° in the trans-square planar complex. L1 was tested in Rh-catalyzed 1,4-addition reactions of arylboronic acids (six examples) to α,β-unsaturated ketones (five examples). In mixed aqueous/cyclohexane solution at 60 °C, addition reactions proceed in up to quantitative yield with a 1:1 arylboronic acid/enone ratio. Yields as high as 77% can be acquired even when one of the coupling partners is sterically encumbered 2,4,6-trimethylphenylboronic acid.

Enantio‐ and Regioselective Heck‐Type Reaction of Arylboronic Acids with 2,3‐Dihydrofuran.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Highly efficient Suzuki–Miyaura coupling reactions catalyzed by bis(oxazolinyl)phenyl–Pd(II) complex

Bis(oxazolinyl)phenyl–palladium(II)(Phebox–Pd) complexes were found to be efficient catalysts for Suzuki–Miyaura coupling reactions of aryl boronic acids and their derivatives with aryl halides to give the corresponding biaryl products in high yield along with moderate enantioslectivities in the case of axially chiral induction. The catalytic activity was attained more than 900,000 of TON and 45,000 of TOF. The catalyst can be recovered quantitatively and could be reused for Suzuki–Miyaura reactions.

Heck-type coupling vs. conjugate addition in phosphine–rhodium catalyzed reactions of aryl boronic acids with α,β-unsaturated carbonyl compounds: a systematic investigation

The competition between Heck-type coupling and conjugate addition in phosphine-rhodium catalyzed reactions of aryl boronic acids with alpha,beta-unsaturated carbonyls has been systematically investigated in a toluene-H(2)O biphasic system. Aside from the intrinsic nature of rhodium and the enolization of carbonyls, the phosphine supporting ligand on rhodium, the ratio of aryl boronic acid to alpha,beta-unsaturated carbonyl and the pH value of the aqueous phase were found to affect the competition significantly. Highly selective rhodium-based catalyst systems have therefore been developed for both Heck-type coupling and conjugate addition by synergistically tuning the supporting ligand, the boronic acid to olefin ratio and other reaction conditions. Conjugate addition with selectivity >99% and Heck-type coupling with selectivity of up to 100%, 98% and 84% for acrylates, acrylamides and methyl vinyl ketone, respectively, could be achieved in the rhodium-catalyzed reactions of aryl boronic acids with alpha,beta-unsaturated carbonyls using the corresponding optimized rhodium-based catalyst systems.

Rhodium‐Catalyzed Cascade Reaction of 1,6‐Enynes Involving Addition, Cyclization, and β‐Oxygen Elimination

The reaction of arylboronic acids with 1,6-enynes that contain an allylic ether moiety is catalyzed by a rhodium(I) complex to produce cyclopentanes with a tetrasubstituted exo olefin and a pendant vinyl group. The reaction is initiated by the regioselective addition of an arylrhodium(I) species to the carbon-carbon triple bond of the 1,6-enyne. The resulting alkenylrhodium(I) compound subsequently undergoes intramolecular carborhodation of the allylic double bond in a 5-exo-trig mode. Beta elimination of the methoxy group affords the cyclization product and the catalytically active methoxorhodium(I) species. The use of alkyl Grignard reagents instead of arylboronic acids as organometallic nucleophiles was also examined.