34662-93-6Relevant academic research and scientific papers
Build-up of double carbohelicenes using nitroarenes: Dual role of the nitro functionality as an activating and leaving group
Su, Rongchuan,Yang, Yudong,You, Jingsong,Zhou, Fujian,Zhou, Fulin
, p. 7424 - 7428 (2020/09/09)
The construction of double carbohelicenes is highly fascinating yet challenging work. Disclosed herein is a streamlined and simplified synthetic route to double carbohelicenes starting from nitroarenes through sequential nitro-activated ortho-C-H arylation, denitrative alkenylation and intramolecular cyclodehydrogenation. In this synthetic strategy, the nitro group plays a dual role namely as a leaving group for the denitrative alkenylation and as an activating group for ortho-C-H arylation, which is distinct from those of aryl halides in a conventional coupling reaction. In this work, the palladium-catalyzed Heck-type alkenylation of nitroarenes has been presented, in which the conventionally inert Ar-NO2 bond is cleaved. This work provides a novel synthetic strategy for polycyclic aromatic hydrocarbons (PAHs). This journal is
Cycloreversion of 1-(1-Naphthyl)-5-phenylbicyclo[3.2.0]hept-6-ene to 1-(1-Naphthyl)-4-phenyl-1,3-cycloheptadiene by Triplet Sensitization and Direct Irradiation
Nakabayashi, Kenichi,Arimura, Junichi,Yasuda, Masahide,Shima, Kensuke,Takamuku, Setsuo
, p. 1313 - 1317 (2007/10/03)
The cycloreversion of 1-(1-naphthyl)-5-phenylbicyclo[3.2.0]hept-6-ene (1b) to 1-(1-naphthyl)-4-phenyl-1,3-cycloheptadiene (2b) upon benzophenone (BP) sensitization and direct irradiation has been investigated. The triplet sensitization of 1b in benzene gave 2b quantitatively up to a stationary state where the quantum yield was 0.96. The triplet state of 2b (λmax =455 nm, τ=4.6 μs) was formed by the pulse radiolysis of 1b in benzene. It has been found that cycloreversion proceeds by an adiabatic mechanism via a triplet state. The quantum yield for the formation of 2b by the irradiation of 1b at 313 nm was determined to be 0.17 in hexane. The fluorescence spectra of 1b and 2b indicated that diabatic cycloreversion occurred via a singlet state. The singlet and triplet energies of 1b, as well as those of 2b, were estimated to be 88, 60, 72, and 39 kcal mol-1, respectively. The effect of a substitution of the naphthalene chromophore on bicyclo[3.2.0]hept-6-ene was estimated.
