carbonylation reaction for the synthesis of fluoren‐9‐ones from 2‐halogenated biphenyls using phenyl formate as a carbon monoxide surrogate was achieved. The combined use of cesium carbonate and o‐anisic acid resulted in a remarkable rate enhancement, where the reaction was complete within 3 min in some cases. Mechanistic studies indicated that the turnover‐limiting step of the reaction was the C−H bond‐cleaving
A highly efficient palladium‐catalyzed disilylation reaction of arylhalides through C−H activation has been developed for the first time. The reaction has broad substrate scope. A variety of arylhalides can be disilylated by three types of C−H activation, including C(sp2)−H, C(sp3)−H, and remote C−H activation. In particular, the reactions are also unusually efficient. The yields are essentially
for the synthesis of fluorene and its derivatives starting from 2-iodobiphenyls and CH2Br2. A range of fluorene derivatives can be synthesized under relatively mild conditions. The reaction proceeds via a tandem palladium-catalyzed dual C–C bond formation sequence through the key dibenzopalladacyclopentadiene intermediates, which are obtained from 2-iodobiphenyls through palladium-catalyzed C–H activation
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
α-Bromoacrylic Acids as C1 Insertion Units for Palladium-Catalyzed Decarboxylative Synthesis of Diverse Dibenzofulvenes
作者:Minghao Zhang、Wenbo Deng、Mingjie Sun、Liwei Zhou、Guobo Deng、Yun Liang、Yuan Yang
DOI:10.1021/acs.orglett.1c01888
日期:2021.8.6
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