Regulation of diastereoselectivity in the carbocyclization of allenyl (S)-N-tert-butylsulfinimines through a three-component assembly

Allenyl sulfinimines can be stereoselectively cyclized with hexamethylditin under palladium catalysis conditions followed by a selection of additives for an activated transmetalation. Reactivity and diastereoselectivity for the cyclization strongly depend on the characteristics of additives. A highly diastereoselective synthesis of five-membered rings is achieved from the reaction of the corresponding allenyl (S)-N-tert-butylsulfinimies through the following sequence. After the distannylation of the allenyl group with hexamethylditin catalyzed by the Pd complex, stereochemical routes are additive dependent: addition of SnCl4 affords a cis ring exclusively, whereas a trans ring is formed predominantly by the introduction of B-bromocatecholborane. Extension of the methodology to the synthesis of six-membered cis rings is achieved by using B-bromocatecholborane. Stereochemical relationships of products were unambiguously deduced by X-ray crystallography.

Enantioselective synthesis of decalin structures with all-carbon quaternary centers via one-pot sequential Cope/Rauhut-Currier reaction

The first example of one-pot sequential Cope/Rauhut-Currier reactions are reported and used to make functionalized decalin structures with all-carbon quaternary stereocenters. The substrates for the new sequential reaction are generated through a six-step sequence including an enantioselective Birch reduction-allylation reaction which makes the overall process asymmetric.

Copper catalysed Ullmann type chemistry: from mechanistic aspects to modern development

Cu-catalysed arylation reactions devoted to the formation of C-C and C-heteroatom bonds (Ullmann-type couplings) have acquired great importance in the last decade. This review discusses the history and development of coupling reactions between aryl halides and various classes of nucleophiles, focusing mostly on the different mechanisms proposed through the years. Selected mechanistic investigations are treated more in depth than others. For example, evidence in favour or against radical mechanisms is discussed. Cu(I) and Cu(III) complexes involved in the Ullmann reaction and N/O selectivity in aminoalcohol arylation are discussed. A separate section has been dedicated to the synthesis of heterocyclic rings through intramolecular couplings. Finally, recent developments in green chemistry for these reactions, such as reactions in aqueous media and heterogeneous catalysis, have also been reviewed.

“Quick and click” assembly of functionalised indole rings via metal-promoted cyclative tandem reactions

An efficient and convenient synthesis of a variety of decorated indoles using a three-component tandem metal-catalysed process is described.

Iron catalyzed efficient synthesis of 2-arylbenzothiazoles from benzothiazole and olefins using environmentally benign molecular oxygen as oxidant

An efficient protocol for iron catalyzed arylation of benzothiazole with olefins has been developed using molecular oxygen as a greener oxidant.

Synthesis of 3-aryl-2-aminoquinolines: palladium-catalyzed cascade reactions of gem-dibromovinylanilines with tert-butyl isocyanide and arylboronic acids

A three-component cascade reaction involving gem-dibromovinylanilines, tert-butyl isocyanide and arylboronic acids for the efficient synthesis of 3-aryl-2-aminoquinolines has been developed.

Disulfides as efficient thiolating reagents enabling selective bis-sulfenylation of aryl dihalides under mild copper-catalyzed conditions

Selective bis-sulfenylation reactions of aryl dihalides have been achieved by copper-catalyzed C–S coupling reactions under mild conditions of refluxing EtOH (80 °C).

An efficient and facile synthesis of benzimidazo[1,2-a]benzimidazoles via copper-catalyzed domino addition/double cyclization

A variety of benzimidazo[1,2-a]benzimidazole derivatives were efficiently and facilely assembled from bis-(o-haloaryl)carbodiimides and primary amines through a Cu-catalyzed domino addition/double cyclization process.

Microwave-assisted synthesis of 5,6-dihydroindolo[1,2-a]quinoxaline derivatives through copper-catalyzed intramolecular N-arylation

An efficient and practical protocol has been developed to synthesize 5,6-dihydroindolo[1,2-a]quinoxaline derivatives by CuI-catalyzed intramolecular N-arylation under microwave irradiation. This method rapidly afforded the tetracyclic products with good to excellent yields (83–97%) in short reaction times (45–60 min).

Copper-catalyzed multicomponent coupling/cycloisomerization reaction between substituted 1-formyl-9H-β-carbolines, secondary amines, and substituted alkynes for the synthesis of substituted 3-aminoindolizino[8,7-b]indoles

A copper-catalyzed efficient one step three component strategy for preparing a library of aminoindolizino[8,7-b]indoles from N-substituted 1-formyl-9H-β-carbolines, secondary amines, and substituted alkynes with high atom economy has been developed.

Cu-catalyzed reaction of 1,2-dihalobenzenes with 1,3-cyclohexanediones for the synthesis of 3,4-dihydrodibenzo[b,d]furan-1(2H)-ones

The Cu(I)-catalyzed reaction of 1-bromo-2-iodobenzenes and other 1,2-dihalobenzenes with 1,3-cyclohexanediones in DMF at 130 °C using Cs(2)CO(3) as a base and pivalic acid as an additive selectively delivers 3,4-dihydrodibenzo[b,d]furan-1(2H)-ones with yields ranging from 47 to 83%. The highly regioselective domino process is based on an intermolecular Ullmann-type C-arylation followed by an intramolecular Ullmann-type O-arylation. Substituted products are accessible by employing substituted 1-bromo-2-iodobenzenes and substituted 1,3-cyclohexanediones as substrates. Reaction with an acyclic 1,3-diketone yields the corresponding benzo[b]furan.