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.

中文翻译：

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钯催化 2-碘联苯与烯基溴的偶联反应构建 9-(二有机亚甲基)芴

已经报道了通过钯催化的 2-碘联苯与烯基溴的偶联反应构建 9-（二有机亚甲基）芴的原子经济协议。该反应通过C-H活化/氧化加成/还原消除/分子内Heck偶联反应进行，以良好的收率得到一系列9-(二有机亚甲基)芴。对照实验表明，五元钯环作为关键中间体，β-H 消除作为限速步骤。