1393641-94-5Relevant academic research and scientific papers
Facile access to 2,2-diaryl 2: H -chromenes through a palladium-catalyzed cascade reaction of ortho -vinyl bromobenzenes with N -tosylhydrazones
Huang, Xueliang,Yu, Yinghua,Zhang, Heng
, p. 5115 - 5119 (2020/07/23)
A palladium-catalyzed cascade reaction of ortho-vinyl bromobenzenes with N-tosylhydrazones has been developed, which provides a facile approach to 2,2-disubstituted 2H-chromenes. The migration of palladium from the aryl to vinyl position is crucial, as the in situ produced vinyl palladium intermediate could further react with diazo compounds to generate the reactive species for the sequential annulation. This journal is
A facile synthesis of 2h-chromenes and 9-functionalized phenanthrenes through reactions between α,β-unsaturated compounds and arynes
Zhang, Tiexin,Huang, Xian,Wu, Luling
experimental part, p. 3507 - 3519 (2012/07/30)
Facile syntheses of 2H-chromenes or 9-functionalized phenanthrenes under mild conditions in moderate to good yields have been developed. They each involve annulations of arynes with α,β-unsaturated compounds bearing different electron-withdrawing groups (EWGs). Depending on the natures of the different EWGs, the reactions proceed by different pathways: enals react with arynes through a tandem [2+2] cycloaddition/thermal electrocyclic ring-opening/6e-electrocyclization sequence to afford 2H-chromenes, whereas acyl-/ethoxycarbonyl-/cyano-substituted styrenes undergo Diels-Alder reactions with arynes followed by aromatization to afford 9-functionalized phenanthrenes. The scope, limitations, regioselectivities and mechanisms have been studied and are discussed in detail. Depending on the natures of different EWGs in α,β-unsaturated compounds, the reactions between arynes and α,β-unsaturated compounds proceed by different tandem pathways to afford either 2H-chromenes or 9-functionalized phenanthrenes in a selective manner, which is of potential pharmaceutical interest.
