Miyaura Coupling Reaction Research Articles

A Polymeric Colorimetric Sensor with Excited-State Intramolecular Proton Transfer for Anionic Species

A π-conjugated polymer with 2,5-bis(benzoxazol-2′-yl)benzene-1,4-diol fluorene units is synthesized by using a Suzuki−Miyaura coupling reaction (Mw = 1.3 × 104; PDI = 1.8). The polymer exhibits UV–vis absorption, λmax ≈ 421 nm, and fluorescence, λmax ≈ 616 nm. The observed large Stokes shift (∼200 nm) is attributed to an excited-state intramolecular proton-transfer process. The addition of anionic species (hydroxide, fluoride, and acetate) causes the absorption λmax to be red-shifted to 510–540 nm and the fluorescence quantum efficiency to be increased by a factor of ∼20. Through the study of a model compound, the structure of the anion complex is determined to be deprotonated monoanion, as evidenced from the Benesi−Hildebrand plot and electron-spray mass spectrometry. On the basis of a large spectral response in absorption and significant fluorescence enhancement, the material could be useful for dual-channel detection of anions.

Chain-Growth Polymerization for the Synthesis of Polyfluorene via Suzuki−Miyaura Coupling Reaction from an Externally Added Initiator Unit

Palladium-catalyzed polycondensation of 2-(7-bromo-9,9-dioctyl-9H-fluoren-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1a) with tBu3PPd(Ph)Br (2) via Suzuki−Miyaura coupling reaction was investigated. The polymerization in a mixture of THF and 2 mol/L aqueous solution of Na2CO3 proceeded smoothly at room temperature and afforded well-defined polyfluorenes with narrow molecular weight distributions. MALDI-TOF mass spectroscopy showed that the obtained polymers have a phenyl group at one end. The relationships of conversion to number-average molecular weight (Mn) and feed ratio to Mn were linear. These results demonstrate that this organometallic polycondensation proceeds through a chain-growth polymerization mechanism from an initiator unit derived from the catalyst.

Synthesis, Structural, and Electron Topographical Analyses of a Dialkylbiaryl Phosphine/Arene-Ligated Palladium(I) Dimer: Enhanced Reactivity in Suzuki−Miyaura Coupling Reactions

The treatment of bis(2-(dicyclohexylphosphino)-2',6'-dimethoxybiphenyl)PdCl2 with AgBF4 produces an air-stable phosphine/arene-ligated Pd(I) dimer with two seemingly identical Pd-arene interactions by X-ray crystallography. However, NMR and theoretical electron topographical analyses of this complex distinguish between these two interactions. One interaction is classified as an arenium-like complex, while the other is classified as a pi-interaction. Additionally, this complex is a suitable precatalyst for high yielding Suzuki-Miyaura coupling reactions in short reaction times.

Synthesis of the Benzhydryl Motif via a Suzuki−Miyaura Coupling of Arylboronic Acids and 3-Chloroacrylonitriles

[reaction: see text] A simple two-step procedure for synthesizing functionalized benzhydrylamines is described. The first step involves a Suzuki-Miyaura coupling reaction between arylboronic acids and 3-chloro-3-arylacrylonitriles at 45 degrees C. A variety of boronic acids and substituted acrylonitriles can be used for the reaction. The resulting 3,3-diaryl-substituted acrylonitriles can be converted into their corresponding Boc-protected amines by catalytic hydrogenation.

Palladium-Catalyzed Cross-Coupling of B-Benzyl-9-borabicyclo[3.3.1]nonane To Furnish Methylene-Linked Biaryls

[reaction: see text] Benzylboranes are noticeably uncommon partners within Suzuki-Miyaura coupling reactions. B-Benzyl-9-BBN was successfully coupled to a range of aryl/heteroaryl bromides, chlorides, and triflates to give pharmacologically important methylene-linked biaryl structures. Activated, deactivated, and sterically hindered substrates were successfully coupled in high yield using Pd(PPh(3))(4) or Pd(OAc)(2) with SPhos as the catalyst system.

A Novel Methodology for Efficient Removal of Residual Palladium from a Product of the Suzuki−Miyaura Coupling with Polymer-Supported Ethylenediamine Derivatives

In our investigation to efficiently remove residual palladium from a drug candidate prepared via the Suzuki−Miyaura coupling reaction, it was found that polymer-bound ethylenediamines can absorb both Pd(0) and Pd(II). This property was applied to the removal of residual palladium from the crude 2‘-cyanobiphenyl product (R)-2 obtained by the Suzuki−Miyaura coupling of an optically active bromobenzene derivative (R)-1 with a boronate 3. Treatment with the polymer-bound ethylenediamines reduced the palladium content of the crude product from 2000−3000 to 100−300 ppm. Subsequent purification by salt formation with di-p-toluoyl-d-tartaric acid (DTTA) attained a low palladium content of less than 10 ppm.

Studies Toward the Total Synthesis of Gymnocin A, a Cytotoxic Polyether: A Highly Convergent Entry to the F—N Ring Fragment.

An efficient and highly convergent synthesis of the FGHIJKLMN ring fragment of gymnocin A, a cyctotoxic polycyclic ether isolated from the notorious red-tide forming dinoflagellate Gymnodinium mikimotoi, has been achieved. The present synthesis relied on extensive use of the B-alkyl Suzuki−Miyaura coupling reaction.