RESUMO
Ru(II)-catalyzed strategies were developed for the [4 + 1] and [4 + 2] oxidative coupling between N-aryl-2,3-dihydrophthalazine-1,4-diones and 1,4-benzoquinones, achieving spiro-indazolones and fused-cinnolines, respectively. Mild, aerobic and external oxidant-free conditions, as well as the use of a ruthenium catalyst for such (spiro)annulative strategies with quinones over reported Rh/Ir-catalyts, underline the rewards of the disclosed protocols.
Assuntos
Rutênio , Compostos de Espiro , Catálise , Compostos Heterocíclicos com 2 Anéis , Estrutura Molecular , QuinonasRESUMO
A mild Rh-catalyzed method was developed for the synthesis of hydroxyimino functionalized indazolo[1,2-a]cinnolines and phthalazino[2,3-a]cinnolines by reductive [4 + 2] annulation between 1-arylindazolones and 2-aryl-2,3-dihydrophthalazine-1,4-diones with varied nitroolefins. The targeted oxime decorated tetracyclic fused cinnolines were synthesized via sequential C-H activation/olefin insertion/reduction under reducing-agent-free conditions.
Assuntos
Compostos Heterocíclicos com 2 Anéis , Ródio , Catálise , Substâncias RedutorasRESUMO
A direct ortho-Csp2 -H acylmethylation of 2-aryl-2,3-dihydrophthalazine-1,4-diones with α-carbonyl sulfoxonium ylides is achieved through a RuII -catalyzed C-H bond activation process. The protocol featured high functional group tolerance on the two substrates, including aryl-, heteroaryl-, and alkyl-substituted α-carbonyl sulfoxonium ylides. Thereafter, 2-(ortho-acylmethylaryl)-2,3-dihydrophthalazine-1,4-diones were used as potential starting materials for the expeditious synthesis of 6-arylphthalazino[2,3-a]cinnoline-8,13-diones and 5-acyl-5,6-dihydrophthalazino[2,3-a]cinnoline-8,13-diones under Lawesson's reagent and BF3 â OEt2 mediated conditions, respectively. Of these, the BF3 â OEt2 -mediated cyclization proceeded in DMSO as a solvent and a methylene source via dual C-C and C-N bond formations.
RESUMO
An efficient one-pot Ir-catalyzed method was developed for the synthesis of indazolone-fused cinnolines by [4 + 2] annulation of 1-arylindazolones with α-diazo carbonyl compounds via sequential C-H activation/carbene insertion/cyclization in a tandem manner. This method has excellent tolerance towards electron-withdrawing and electron-donating functional groups on 1-arylindazolone. This method was also found to be applicable to cyclic α-diazo carbonyl compounds.
RESUMO
A Rh(III)-catalyzed strategy involving the [4+1] annulation of 2-arylphthalazine-1,4-diones with α-diazo carbonyl compounds was developed, accessing a series of unprecedented hydroxy-dihydroindazolo-fused phthalazines in good to excellent yields. By varying the additive, phthalazino-fused cinnolines were synthesized under Rh-catalyzed conditions via [4+2] annulation between the same starting materials. Notably, such two strategies showed a good functional group tolerance and high atom efficiency.