RESUMO
The first stereoselective total synthesis of a potent antitumor alkaloid, discorhabdin A (1), which is a unique sulfur-containing pyrroloiminoquinone alkaloid, is described. The key step in the stereocontrolled total synthesis of 1 involves both a diastereoselective oxidative spirocyclization using a hypervalent iodine(III) reagent and an efficient construction of the labile and highly strained N,S-acetal skeleton. These methodologies provide a breakthrough in the total syntheses of these promising new antitumor agents, discorhabdins and their analogues, which should serve as valuable probes for structure-activity studies.
Assuntos
Antineoplásicos/síntese química , Quinonas/química , Quinonas/síntese química , Compostos de Espiro/química , Compostos de Espiro/síntese química , Tiazepinas/química , Tiazepinas/síntese química , Acetais/química , Antineoplásicos/química , Ciclização , Naftoquinonas/síntese química , Naftoquinonas/química , Oxirredução , Estereoisomerismo , Enxofre/químicaAssuntos
Alcaloides/síntese química , Antineoplásicos/síntese química , Quinonas/síntese química , Compostos de Espiro/síntese química , Enxofre/química , Tiazepinas , Alcaloides/química , Antineoplásicos/química , Reagentes de Ligações Cruzadas , Ciclização , Quinonas/química , Compostos de Espiro/químicaRESUMO
A novel and efficient oxidative biaryl coupling reaction of phenol ether derivatives using a combination of hypervalent iodine(III) reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA), and heteropoly acid has been developed.
Assuntos
Compostos Heterocíclicos com 3 Anéis/síntese química , Alcaloides/síntese química , Fatores Biológicos/síntese química , Ciclização , Indicadores e Reagentes , Iodo/química , Oxigênio/química , Fenol/química , Polieletrólitos , Polímeros/químicaRESUMO
The oxidative intramolecular coupling reaction of phenol ether derivatives (nonphenolic derivatives) on treatment with a novel combination of a hypervalent iodine(III) reagent, phenyliodine bis(trifluoroacetate) (PIFA), and heteropoly acid (HPA) was studied. Biaryl compounds were obtained in excellent yields on treatment of highly substituted phenol ethers. On the other hand, spirodienones were specifically formed when one of the preferred arylic coupling sites was substituted with a methoxy group in the para position.