A straightforward anionic coupling for the synthesis of ortho-bromobiaryls

Non-catalyzed anionic coupling of aryllithiums with 1,2-dibromobenzene gives straightforward access to valuable ortho-bromobiaryls.     

Practical synthesis of pinacolborane for one-pot synthesis of unsymmetrical biaryls via aromatic C-H borylation-cross-coupling sequence

A method for practical preparation of pinacolborane from borane-diethylaniline and pinacol was newly developed. Aromatic C-H borylation of arenes with pinacolborane or bis(pinacolato)diboron catalyzed by 1/2[Ir(OMe)(COD)]₂-(4,4′-di-tert-butyl-2,2′-bipyridine) at 25 °C in hexane to give arylboronic esters was directly followed by cross-coupling with aromatic bromides at 60 °C in the presence of PdCl₂(dppf) (3.0 mol %) and K₃PO₄ in DMF. This one-pot, two-step procedure provided a variety of unsymmetrical biaryls in high yields.     

Ultrasound-assisted synthesis of symmetrical biaryls by palladium-catalyzed detelluration of 1,2-diarylditellanes

An ultrasound-assisted synthesis of functionalized symmetrical biaryls with electron-withdrawing or electron-donating substituents is described and illustrated by the palladium-catalyzed detelluration of 1,2-diarylditellanes. This procedure offers easy access to symmetrical biaryls in short reaction time and the products are achieved in good to excellent yields.     

Transition metal catalyzed cross-coupling of aryl Grignard reagents with aryl fluorides via Pd- or Ni-activation of the C-F bond: an efficient synthesis of unsymmetrical biaryls - application of microwave technology in ligand and catalyst screening

Biaryl compounds are prevalent in both nature and in active pharmaceutical ingredients. The palladium and nickel catalyzed cross-coupling of aryl Grignard reagents with aryl fluorides reported herein affords moderate to excellent yields of the corresponding unsymmetrical biaryls. In addition, the first example of a biaryl cross-coupling utilizing unactivated aryl fluorides under phosphine free palladium conditions is reported. Microwave technology allowed rapid optimization of catalyst systems, which identified several ligands for this cross-coupling reaction.     

Regioselective synthesis of highly-substituted biaryls by reaction of vinyl malononitriles with acetylenic esters

The one-pot procedure for synthesis of highly-substituted biaryl derivatives has been described via cyclocondensation reaction between vinyl malononitriles and acetylenic esters. A series of complex biaryls containing one-donor and three-acceptor moieties was obtained with good yields.     

Synthesis of fused or not β-lactam-biaryl hybrids by free radical aryl-aryl coupling of 2-azetidinone-tethered haloarenes

cis and trans-Aryl-2-azetidinone-tethered haloarenes can be stereoselectively prepared using the ketene-imine cyclization. These β-lactam-tethered haloarenes were used for the regiocontrolled preparation of β-lactam-biaryl hybrids including fused tetracyclic biaryl-2-azetidinones as well as C4-dearylated not fused biphenyl‐2-azetidinones via aryl-aryl radical cyclization and/or rearrangement. Alternatively, trans-dibenzocarbacephems could be stereoselectively prepared, both in racemic and enantiopure form, through the Staudinger reaction between phenanthridine and activated ketenes.     

An efficient coupling reaction of anionic propargyl and organic halides

The organometallic produced by controlled lithiation of allene functions as an efficient propargylic anion equivalent in coupling reactions with alkyl and allyl halides.     

Facile synthesis of symmetrical functionalized biaryls from aryl halides catalyzed by commercial zinc dust using ammonium formate

Reductive homocoupling of aryl halides in the presence of commercial zinc dust and ammonium formate in methanol produces biaryls in good to excellent yields. Aryl halides having either electron-donating or electron-withdrawing groups underwent smooth coupling to afford the corresponding symmetrical biaryls. Addition of 1 equiv of sodium hydroxide enhanced the coupling reaction rate. Commercial zinc dust is inexpensive, widely available and can be used without any auxiliary catalysts such as Pd(0) and/or Ni(0).     

An efficient and regioselective iodination of electron-rich aromatic compounds using N-chlorosuccinimide and sodium iodide

An efficient and regioselective method for iodination of electron-rich aromatic compounds was found using N-chlorosuccinimide and sodium iodide in AcOH with short reaction times. This method is also applicable to non-benzenoid aromatic or heteroaromatic compounds.     

Aminoborylation/Suzuki-Miyaura tandem cross coupling of aryl iodides as efficient and selective synthesis of unsymmetrical biaryls

Sequential borylation of a first aryl iodide using a dialkylaminoborane followed by a Suzuki-Miyaura cross coupling of second aryl iodide ended up with an efficient, selective and practical synthesis of unsymmetrical biaryls. This tandem coupling shows a wide range of applicability.     

Novel and efficient copper-catalysed synthesis of nitrogen-linked medium-ring biaryls

Herein, a new copper-catalysed strategy for the synthesis of rare nitrogen-linked seven-, eight- and nine-membered biaryl ring systems is described. It is proposed that the reaction proceeds through a highly activated intramolecularly co-ordinated copper catalyst. The process is technically simple, proceeds under relatively mild conditions, displays a broad substrate scope and forms biologically valuable products that are difficult to synthesise by other methods. We envisage that this methodology will prove useful in a wide synthetic context, with possible applications in both target-oriented and diversity-oriented synthesis.     

An efficient synthesis of 6,9-disubstituted purin-8-ones via copper-catalyzed coupling/cyclization

An efficient and novel synthesis of 6,9-disubstituted purin-8-ones has been developed. Starting from dichloropyrimidin-5-ylcarbamate, CuCl/amino acid catalyzed coupling/cyclization reaction with amines was achieved to afford 9-substituted 6-chloropurin-8-ones. Then a microwave-assisted amination procedure was carried out for the synthesis of 6,9-disubstituted purin-8-ones in moderate to good yields.     

Straightforward access to 2-iminoisoindolines via three-component coupling of arynes, isocyanides and imines

A three-component coupling reaction of arynes, isocyanides and N-tosylaldimines has been developed to offer modest to high yields of diverse 2-iminoisoindolines in one step. Intermediacy of arynes in the coupling has been verified by the reaction of unsymmetrical arynes.     

An efficient PIFA-mediated synthesis of a directly linked zinc chlorin dimer via regioselective oxidative coupling

The synthesis of a directly linked zinc chlorin dimer was first achieved by a facile and efficient oxidative coupling of zinc chlorin monomers with phenyliodine bis(trifluoroacetate) (PIFA). The reaction shows high regioselectivity at the 20-position near the hydrogenated pyrrole ring producing selective dichlorin in 74% yield.     

An expedient synthesis of ellipticine via Suzuki-Miyaura coupling

A simple and efficient total synthesis of ellipticine was developed via the Suzuki-Miyaura coupling of sterically sensitive 2-hydroxybenzeneboronic acid with a multifunctional aryl halide using Pd(OAc)₂ as a catalyst and Cu(OAc)₂·H₂O as an additive in DMSO/H₂O as a key step followed by double N-arylation and cyclization.     

Negishi cross-coupling of organotellurium compounds: synthesis of biaryls, aryl-, and diaryl acetylenes

A functional group tolerant palladium-catalyzed Negishi coupling of diaryl tellurides with organozinc has been developed. This methodology permits efficient preparation of biaryls, aryl acetylenes and diaryl acetylenes in moderate to good yields. A preliminary study to gain further insight into the reaction was performed using in situ ReactIR technology.     

Asymmetric synthesis of an aminomethyl morpholine via double allylic substitution

The development of an asymmetric route to an aminomethyl morpholine intermediate via palladium-catalysed allylic substitution is described.     

Studies on isocyanides. A facile synthesis of 4,5-dihydro-1,4-benzothiazepin-3(2H)-ones via post-condensation modifications of the Ugi reaction

A series of 4,5-dihydro-1,4-benzothiazepin-3(2H)-ones 9 was prepared via Ugi 4-CC, S_N aliph, and S_N arom. This procedure, which resembles the well-known Hulme’s and Zhu’s protocols, allows a facile access to the above heterocyclic system. Further transformations of the cyclized products appear to be feasible.