Ni-catalysed, domino synthesis of tertiary alcohols from secondary alcohols

The use of in situ generated (NHC)-Ni catalytic species (NHC = N-heterocyclic carbene) allows for the synthesis, in short reaction times, of a variety of tertiary alcohols from secondary alcohols through a domino oxidation-addition protocol

(N-Heterocyclic Carbene)₂‑Pd(0)-Catalyzed Silaboration of Internal and Terminal Alkynes: Scope and Mechanistic Studies

Pd­(ITMe)₂(PhCCPh) acts as a highly reactive precatalyst in the silaboration of terminal and internal alkynes to yield a number of known and novel 1-silyl-2-boryl alkenes. Unprecedented mild reaction temperatures for terminal alkynes, short reaction times, and low catalytic loadings are reported. During mechanistic studies, <i>cis</i>-Pd­(ITMe)₂(SiMe₂Ph)­(Bpin) was directly synthesized by oxidative addition of PhMe₂SiBpin to Pd­(ITMe)₂(PhCCPh). This represents a very rare example of a (silyl)­(boryl)palladium complex. A plausible catalyst decomposition route was also examined

Sonogashira Couplings Catalyzed by Collaborative (<i>N</i>‑Heterocyclic Carbene)-Copper and -Palladium Complexes

A general protocol for the Sonogashira reaction using a 100:1 combination of (<i>N</i>-heterocyclic carbene)-Cu and (<i>N</i>-heterocyclic carbene)-Pd complexes is presented. Catalyst loadings of 1 mol % (NHC)-Cu and 0.01 mol % (NHC)-Pd allow for the coupling of aryl bromides and aryl alkynes, in air and in a non-anhydrous solvent, in high yields

Comparison of the Reactivity of the Low Buried-Volume Carbene Complexes (ITMe)₂Pd(PhCCPh) and (ITMe)₂Pd(PhNNPh)

The novel Pd(0)-azobenzene complex (ITMe)₂Pd­(PhNNPh) (<b>5</b>) (ITMe = 1,3,4,5-tetramethylimidazol-2-ylidene) has been isolated and characterized in the solid state and by cyclic voltammetry. Its reactivity toward E–E′ bonds (E, E′ = Si, B, Ge) has been compared with that of the known carbene complex (ITMe)₂Pd­(PhCCPh) (<b>2</b>). Whereas <b>2</b> reacts with all E–E′ bonds studied, <b>5</b> only reacted with B–B and B–Si moieties, echoing our previous catalytic studies on azobenzenes

Efficient Ni^II₂Ln^III₂ Electrocyclization Catalysts for the Synthesis of <i>trans</i>-4,5-Diaminocyclopent-2-enones from 2‑Furaldehyde and Primary or Secondary Amines

A series of heterometallic coordination clusters (CCs) [Ni^II₂Ln^III₂(L1)₄Cl₂(CH₃CN)₂] 2CH₃CN [Ln = Y (<b>1Y</b>), Sm (<b>1Sm</b>), Eu (<b>1Eu</b>), Gd (<b>1Gd</b>), or Tb (1<b>Tb</b>)] were synthesized by the reaction of (E)-2-(2-hydroxy-3-methoxybenzylidene-amino)­phenol) (H₂L1) with NiCl₂·6­(H₂O) and LnCl₃·x­(H₂O) in the presence of Et₃N at room temperature. These air-stable CCs can be obtained in very high yields from commercially available materials and are efficient catalysts for the room-temperature domino ring-opening electrocyclization synthesis of <i>trans</i>-4,5-diaminocyclopent-2-enones from 2-furaldehyde and primary or secondary amines under a non-inert atmosphere. Structural modification of the catalyst to achieve immobilization or photosensitivity is possible without deterioration in catalytic activity

Conjugated Polymer Nanoparticles by Suzuki–Miyaura Cross-Coupling Reactions in an Emulsion at Room Temperature

A range of stable emulsions of spherical and rod-like conjugated polymer nanoparticles (CPN) were synthesized via Suzuki−Miyaura cross-coupling reactions of 9,9-dioctylfluorene-2,7-diboronic acid bis­(1,3-propanediol) ester with a number of different dibromoarene monomers in xylene, stabilized in water by the nonionic surfactant, Triton X-102. High molar mass poly­(9,9-dioctylfluorene) (PF8), poly­(9,9-dioctylfluorene-<i>alt</i>-benzothiadiazole) (PF8BT), poly­(9,9-dioctylfluorene-<i>alt</i>-4-<i>sec</i>-butylphenyldiphenylamine) (PF8TAA) and poly­(9,9-dioctylfluorene-<i>alt</i>-bithiophene) (PF8T2) emulsions were obtained, at high overall conjugated polymer concentrations (up to 11,000 ppm), in the presence of the palladium complex, (IPr*)­PdCl₂(TEA) and base, tetraethylammonium hydroxide, in nitrogen atmosphere at 30 °C after 24–48 h. TEM analysis of the PF8 and PF8T2 emulsions revealed regular rod-like structures, up to 200 nm in length with aspect ratios of 4–5. PF8BT and PF8TAA formed spherical particles with diameters of between 20–40 nm in TEM analysis. UV–vis absorption spectra of the PF8 emulsions indicated high levels of ordered β-phase configuration (9–10%) in their respective nanoparticles. Absolute photoluminescence quantum yields (Φ) of 21–25% were recorded for these emulsions