RESUMO
A palladium-catalyzed carbon-carbon bond activation-initiated reaction of 2-(3-phenyloxiran-2-yl)benzonitriles with arylboronic acids is reported. Multiple chemical bonds were cleavaged and reconstructed via ß-carbon elimination in this reaction, enabling the construction of valuable benzo-fused dipyrromethenes that are difficult to prepare by other methods. Additionally, a series of benzannulated boron dipyrromethenes are synthesized and show practical significance in terms of expanding the applications and types of fluorescent materials. The proposed mechanism is supported by preliminary mechanistic experiments.
RESUMO
The first example of the palladium-catalyzed tandem addition/cyclization of 2-(2-acylphenoxy)acetonitriles with arylboronic acids has been developed, providing a new strategy for the synthesis of 2-aroyl benzofurans with excellent chemoselectivity and wide functional group compatibility. Preliminary mechanistic experiments indicate that this tandem process involves sequential nucleophilic addition generating 2-(2-acylphenoxy)-1-phenylethan-1-one followed by an intramolecular cyclization. This methodology has also been applied to the synthesis of 2-aroyl indoles and the potent CYP19 inhibitor 1-(benzofuran-2-yl(phenyl)methyl)-1H-1,2,4-triazole.
RESUMO
A novel metal-free catalysis protocol for the synthesis of 1,2-diarylpyrazolo[5,1- b]quinazolin-9(1 H)-ones via intramolecular oxidative C-H amination of ( E)-3-(arylamino)-2-styrylquinazolin-4(3 H)-ones has been developed in moderate to good yield. The method shows good functional group tolerance. The presented approach offers a new synthetic pathway toward the core structures of 2,3-fused quinazolinones. Moreover, the present synthetic route can be readily scaled up to gram quantity without difficulty. A possible mechanism involves a seleniranium ion followed by three-membered ring opening to form the C-N bond.
RESUMO
The first example of the palladium-catalyzed tandem addition/cyclization of 2-(benzylidenamino)benzonitriles with arylboronic acids has been developed. This transformation features good functional group tolerance and provides an alternative synthetic pathway to access 2,4-diarylquinazolines in moderate to good yields. A plausible mechanism for the formation of 2,4-diarylquinazolines involving sequential nucleophilic addition followed by an intramolecular cyclization is proposed.
Assuntos
Nitrilas/química , Paládio/química , Quinazolinas/química , Fenômenos Bioquímicos , Catálise , CiclizaçãoRESUMO
The first example of the palladium-catalyzed, three-component tandem reaction of 2-aminobenzonitriles, aldehydes, and arylboronic acids has been developed, providing a new approach for one-pot assembly of diverse quinazolines in moderate to good yields. A noteworthy feature of this method is the tolerance of bromo and iodo groups, which affords versatility for further synthetic manipulations. Preliminary mechanistic experiments indicate that this tandem process involves two possible mechanistic pathways for the formation of quinazolines via catalytic carbopalladation of the cyano group.
RESUMO
An efficient protocol to construct 2-arylindoles was developed through palladium-catalyzed tandem addition/cyclization of potassium aryltrifluoroborates with aliphatic nitriles in aqueous medium. The use of water as the reaction medium makes the synthesis process environmentally benign. A plausible mechanism for the formation of 2-arylindoles involving sequential nucleophilic addition followed by an intramolecular cyclization is proposed. Moreover, the utility of this catalytic tandem transformation was also demonstrated in an efficient gram-scale synthesis. This method provides an alternative synthetic tool for accessing a more diverse array of 2-arylindoles.
RESUMO
A palladium-catalyzed tandem addition/cyclization of 2-(2-aminoaryl)acetonitriles with arylboronic acids has been developed for the first time, achieving a new strategy for direct construction of indole skeletons. This system shows good functional group tolerance and remarkable chemoselectivity. In particular, the halogen (e.g., bromo and iodo) substituents are amenable to further synthetic elaborations thereby broadening the diversity of the products. Preliminary mechanistic experiments indicate that this transformation involves sequential nucleophilic addition followed by an intramolecular cyclization.
