RESUMO
A regioselective copper-catalyzed ethoxycarbonyl-difluoromethylation of imidazo[1,2-a]pyridines has been developed through sp(2) C-H bond functionalization with BrCF2CO2Et under ambient air. A series of ethoxycarbonyldifluoromethylated imidazo[1,2-a]pyridines with broad functionalities have been synthesized. This methodology is also applicable to imidazo[2,1-b]thiazole and benzo[d]imidazo[2,1-b]thiazole.
RESUMO
A visible light mediated, metal-free process for the thiocyanation of imidazoheterocycles has been developed using eosin Y as a photoredox catalyst under ambient air at room temperature. A library of 3-(thiocyanato)imidazo[1,2-a]pyridines with broad functionalities have been synthesized in high yields. This methodology is also applicable for the selenocyanation of imidazo[1,2-a]pyridine.
RESUMO
A copper-mediated intermolecular annulation of alkyl ketones and ß-nitrostyrenes has been developed for the regioselective synthesis of multisubstituted furan derivatives in good yields. This protocol is applicable to both cyclic and acyclic ketones.
Assuntos
Cobre/química , Furanos/síntese química , Cetonas/química , Estirenos/química , Catálise , Furanos/química , Estrutura Molecular , EstereoisomerismoRESUMO
A catalytic decarboxylative annulation has been developed for the regioselective synthesis of trisubstituted furans by the cycloaddition of ketones with α,ß-unsaturated carboxylic acids under ambient air. A library of furan derivatives were obtained in good yields from the readily available substrates in the combination of a catalytic amount of Cu-salt and a stoichiometric amount of water. Water plays a crucial role in this catalytic transformation.
Assuntos
Ar , Ácidos Carboxílicos/química , Cobre/química , Reação de Cicloadição , Furanos/química , Furanos/síntese química , Cetonas/química , Catálise , Estereoisomerismo , Especificidade por Substrato , Água/químicaRESUMO
The FeCl3/ZnI2-catalyzed aerobic oxidative cyclization between 2-aminobenzothiazole and ketone/chalcone for the synthesis of benzo[d]imidazo[2,1-b]thiazole is described. A variety of fused benzoimidazothiazole derivatives are obtained by this protocol.
Assuntos
Benzotiazóis/química , Cloretos/química , Compostos Férricos/química , Iodetos/química , Cetonas/química , Tiazóis/síntese química , Compostos de Zinco/química , Catálise , Ciclização , Estrutura Molecular , Oxirredução , Tiazóis/químicaRESUMO
An unprecedented formation of benzothiazine during copper(I)-catalyzed oxidative coupling of 2-aminobenzothiazole and terminal alkyne in air has been observed. This unique transformation possibly occurs through the ring opening of 2-aminobenzothiazole and subsequent oxidative coupling with alkyne followed by intramolecular cyclization. A variety of substituted benzo[b][1,4]thiazine-4-carbonitriles are obtained by this protocol.
RESUMO
A diastereoselective synthesis of pyrrolidinooxazolidines was achieved by a metal-free, base-promoted reaction of pyrrolidine and aromatic aldehydes under microwave irradiation. The rare functionalization of an sp(3) C-H bond probably results from an in situ generated azomethine ylide that undergoes cycloaddition with aldehydes.