61370-30-7Relevant academic research and scientific papers
Palladium-catalyzed coupling reaction of 2-iodobiphenyls with alkenyl bromides for the construction of 9-(diorganomethylidene)fluorenes
Zhao, Ya-Heng,Wang, Jian-Long,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
supporting information, p. 8250 - 8253 (2021/10/12)
An atom economical protocol for the construction of 9-(diorganomethylidene)fluorenes through palladium-catalyzed coupling reactions of 2-iodobiphenyls with alkenyl bromides has been reported. The reaction proceeds through the C-H activation/oxidative addition/reduction elimination/intramolecular Heck coupling reaction to afford a series of 9-(diorganomethylidene)fluorenes with good yields. Control experiments demonstrate that a five-membered palladacycle acts as a key intermediate and β-H elimination serves as the rate-limiting step.
α-Bromoacrylic Acids as C1 Insertion Units for Palladium-Catalyzed Decarboxylative Synthesis of Diverse Dibenzofulvenes
Zhang, Minghao,Deng, Wenbo,Sun, Mingjie,Zhou, Liwei,Deng, Guobo,Liang, Yun,Yang, Yuan
, p. 5744 - 5749 (2021/08/18)
Herein α-bromoacrylic acids have been employed as C1 insertion units to achieve the palladium-catalyzed [4 + 1] annulation of 2-iodobiphenyls, which provides an efficient platform for the construction of diverse dibenzofulvenes. This protocol enables the formation of double C(aryl)-C(vinyl) bonds via a C(vinyl)-Br bond cleavage and decarboxylation. It is particularly noteworthy that the method features a broad substrate scope, and various interesting frameworks, such as bridged ring, fused (hetero)aromatic ring, and divinylbenzene, can be successfully incorporated into the products.
New synthesis of dibenzofulvenes by palladium-catalyzed double cross-coupling reactions
Shimizu, Masaki,Nagao, Ikuhiro,Kiyomoto, Shin-Ichi,Hiyama, Tamejiro
, p. 1277 - 1284,8 (2020/09/09)
Palladium-catalyzed double cross-coupling reactions of 1,1-bis(pinacolato) borylalk-1-enes with 2,2′-dibromobiaryls and of 9-stannafluorenes with 1,1-dibromoalk-1-enes have been demonstrated to serve as new synthetic methods for dibenzofulvenes.
Substituent Effects on Exited-State Efficiencies: Thermolysis of 3,3-(2,2'-Biphenyldiyl)-4-methyl-4-aryl-1,2-dioxetanes
Richardson, William H.,Thomson, Stephen A.
, p. 1803 - 1810 (2007/10/02)
Triplet and singlet ketone efficiencies was determined for the thermolysis of a series of nine 3,3-(2,2'-biphenyldiyl)-4-methyl-4-aryl-1,2-dioxetanes, where substituent changes were made in the para and meta positions of the aryl group.Triplet efficiencies (αT), which were determined by trans-stilbene isomerization, ranged from 2.0percent (Ar=p-BrC6H4) to 19.0percent (Ar=C6H5) and the best linear free energy correlation was with ET1(ArCOCH3):log percent αT=(0.518 +/- 0.079)ET1(ArCOCH3)-36.62 +/- 5.73, Sy*x = +/- 0.144, which corresponds to +/- 1.4percent in percent αT.Since no light enhancement resulted upon addition of 9,10-dibromoanthracene, it was concluded that the intercepted triplet ketone product was fluorenone.The results were considered in terms of a triplet ketone exciplex (Scheme I) and equilibrating solvent caged encounter complexes (Scheme II).The singlet efficiencies for all members in the series were essentially constant (percentαS1 = 0.17percent).The chemiluminescent (CL) emission spectra of dioxetanes, where Ar = C6H5 and m-BrC6H4, match the fluorescence spectrum of fluorenone.In addition, the CL emission is not enhanced upon nitrogen purging.From a consideration of activation parameters and ρ reaction constants, a 1,4-dioxy biradical decomposition route for these dioxetanes appears most likely.
