Synthesis of 2-bromo-1H-indenes via copper-catalyzed intramolecular cross-coupling of gem-dibromoolefins

A novel copper-catalyzed intramolecular C–C coupling reaction of activated methylene aromatic compounds with gem-dibromoolefins is described. The reaction can tolerate various functional groups and lead to efficient formation of 2-bromo-1H-indenes.     

The copper-catalyzed cross-coupling reactions of aryl diazonium salts and isocyanides

The copper-catalyzed cross-coupling reaction of aryl diazonium salts and isocyanides has been performed. This is a successful example of preparation of arylcarboxyamides with moderate to good yield under mild conditions.     

Efficient copper-catalyzed cross-coupling of 1-Boc-piperazine with aryl iodides and its application in the synthesis of trazodone

A convenient and practical strategy is developed for the cross-coupling of N-Boc protected piperazines with aryl iodides using CuBr/1,1′-bi-2-naphthol as the catalyst and K₃PO₄ as the base. The protocol affords N-arylated piperazine products in moderate to good yields under the optimized conditions. The application of this catalytic system to the synthesis of trazodone is also successfully demonstrated using commercially available substrates.     

Direct guanidinylation of aryl and heteroaryl halides via copper-catalyzed cross-coupling reaction

A modified Ullmann reaction using p-methoxybenzyl (PMB) guanidine as guanidinylation agent yielded various aryl and heteroaryl guanidines in good yields.     

Oxazolinethiones and oxazolidinethiones for the first copper-catalyzed desulfurative cross-coupling reaction and first sonogashira applications

Cyclic thionocarbamates, namely chiral oxazolidinethiones (OZT) and aromatic oxazolinethiones (OXT), were involved, for the first time, in Sonogashira cross-coupling. A cooperative effect of two different copper (I) species-CuI and CuTC-accounts for this new copper-catalyzed desulfurative carbon-carbon cross-coupling reaction. This cooperative reactivity could also be extended to other copper (I) catalysts.     

Efficient copper-catalyzed C-S cross-coupling of heterocyclic thiols with aryl iodides

A copper-catalyzed cross-coupling of heterocyclic thiols with aryl iodides is reported. The reaction was carried out in the presence of CuI (5 mol %), 1,10-phenanthroline (10 mol %) and K₂CO₃ (1.3 equiv) in DMF at 120 °C. A variety of heterocyclic sulfides were prepared in high selectivities and yields.     

Adamantylazoles: XI. Reaction of 1-phenyltetrazole-5-thione with adamantan-1-ol in strong acids

The reaction of 1-phenyltetrazole-5-thione with adamantan-1-ol in sulfuric acid gave 3-(1-adamantyl)-1-phenyltetrazole-5-thione having a mesoionic structure, 5-(1-adamantylsulfanyl)-1-phenyltetrazole, and 3-(1-adamantyl)-5-(1-adamantylsulfanyl)-1-phenyltetrazolium hydrogen sulfate. Hydrolysis of 5-(1-adamantylsulfanyl)-1-phenyltetrazole led to the formation of 1-phenyltetrazol-5-one. The adamantylation process is reversible.     

Iron/copper-catalyzed C-C cross-coupling of aryl iodides with terminal alkynes

Synergic effect of iron and copper salts as catalysts for the Sonogashira-Hagihara cross-couplings of aryl iodides with terminal alkynes is demonstrated. High yields of cross-coupled products are obtained under conditions that are smoother than those using only CuI as catalyst. Furthermore no expensive or/and toxic ligand is required.     

Copper-mediated and copper-catalyzed cross-coupling of indoles and 1,3-azoles: double C-H activation

A new bronze age: the described copper-mediated cross-coupling with double C-H activation can provide a convergent access to indole-containing biheteroaryls that are of high interest in pharmaceutical and medicinal chemistry. In this strategy an easily attachable and detachable 2-pyrimidyl directing group is used. Moreover, a variant that is catalytic in copper is achieved by using atmospheric oxygen as an ideal co-oxidant.     

Alkali-metal-mediated manganationII of functionalized arenes and applications of ortho-manganated products in Pd-catalyzed cross-coupling reactions with iodobenzene

Extending the recently introduced concept of "alkali-metal-mediated manganation" to functionalised arenes, the heteroleptic sodium manganate reagent [(tmeda)Na(tmp)(R)Mn(tmp)] (1; TMEDA=N,N,N',N'-tetramethylethylenediamine, TMP=2,2,6,6-tetramethylpiperidide, R=CH2SiMe3) has been treated with anisole or N,N-diisopropylbenzamide in a 1:1 stoichiometry in hexane. These reactions afforded the crystalline products [(tmeda)Na(tmp)(o-C6H4OMe)Mn(tmp)] (2) and [(tmeda)Na(tmp){o-{C(O)N(iPr)2C6H4}Mn(CH2SiMe3] (3), respectively, as determined from X-ray crystallographic studies. On the basis of these products, it can be surmised that reagent 1 has acted, at least partially and ultimately, as an alkyl base in the first reaction liberating the silane Me4Si, but as an amido base in the second reaction liberating the amine TMPH. Both of these paramagnetic products 2 and 3 have contacted ion-pair structures, the key features of which are six-atom, five-element (NaNMnCCO) and seven-atom, five-element (NaNMnCCCO) rings, respectively. Manganates 2 and 3 were successfully cross-coupled with iodobenzene under [PdCl(2)(dppf)] (dppf=1,1'-bis(diphenylphosphino)ferrocene) catalysis to generate unsymmetrical biaryl compounds in yields of 98.0 and 66.2 %, respectively. Emphasizing the importance of alkali-metal mediation in these manganation reactions, the bisalkyl Mn reagent on its own fails to metalate the said benzamide, but instead produces the monomeric, donor-acceptor complex [Mn(R)2{(iPr)2-NC(Ph)(==O)}2] (5), which has also been crystallographically characterised. During one attempt to repeat the synthesis of 2, the butoxide-contaminated complex [{(tmeda)Na(R)(OBu)(o-C6H4OMe)Mn}2] (6) was obtained. In contrast to 2 and 3, due to reduced steric constraints, this complex adopts a dimeric arrangement in the crystal, the centrepiece of which is a twelve atom (NaOCCMnC)2 ring.     

N- And S-Alkylation of 3-(1-Aadamantyl)-4-methyl-1,2,4-triazole-5-thiol and 2-(1-Adamantyl)-1,3,4-oxadiazole-5-thiol

ABSTRACT

-The reaction of 3-(1-adamantyl)-4-methyl-1,2,4-triazole-5-thiol 1 with certain 2-aminoethyl chlorides in alkaline medium yielded a separable mixture of the S-(2-aminoethyl) derivatives 2 and the N-(2-aminoethyl) derivatives 3. Meanwhile, alkylation of 2-(1-adamantyl)-1,3,4-oxadiazole-5-thiol 4 with 2-aminoethyl chlorides under the same conditions yielded only the S-alkyl derivatives 5. Interaction of 4 with primary or secondary amines and formaldehyde solution yielded the corresponding N-aminomethyl derivatives in high yields.     

Reusable copper-catalyzed cross-coupling reactions of aryl halides with organotins in inexpensive ionic liquids

A combination of Cu2O nanoparticles with P(o-tol)3 shows highly catalytic activity for the Stille cross-coupling reaction. A series of copper catalysts and ligands were evaluated, and Cu2O nanoparticles combined with P(o-tol)3 provided the best results. In the presence of Cu2O nanoparticles and P(o-tol)3, a variety of aryl halides including aryl chlorides underwent the Stille reaction with organotins smoothly in moderate to excellent yields using inexpensive TBAB (n-Bu4NBr) as the medium. It is noteworthy that the Cu2O/P(o-tol)3/TBAB system can be recovered and reused at least three times without any loss of catalytic activity among the reactions of aryl iodides and activated aryl bromides.     

Synthesis of functionalized diarylmethanes via a copper-catalyzed cross-coupling of arylmagnesium reagents with benzylic phosphates

A combination of copper chloride, triethyl phosphite, and tetrabutylammonium iodide is a very efficient catalytic system for the synthesis of polyfunctionalized diarylmethanes, using the cross-coupling reaction of arylmagnesium halides with benzylic phosphates. The antibiotic Trimethoprim has been prepared using this Cu(I)-catalyzed cross-coupling in 52% overall yield (four steps).