钯催化Heck反应制备长共轭生色二苯乙烯衍生物

Synthesis of Stilbene Derivatives with Long Conjugated Structure by Pd-catalyzed Heck Reaction

采用Heck反应合成出6个带有不同推拉电子基团的二苯乙烯衍生物，产率68％～84％。研究了反应物分子结构对Heck偶联反应的影响，对实验条件进行了优化并探讨了其反应机理。结果表明，反应温度120℃，溶剂DMF和Et3N体积比为2：1时可以获得较高产率。同时我们还发现，不同的反应物结构对Heck反应产率的影响较大，随着反应物中双键的电子云密度的降低（对甲基苯乙烯〉苯乙烯〉4-乙烯吡啶），反应产率依次降低；芳卤的反应活性表现为：NO2-Ar-Br〉H—Ar—Br〉CH3-Ar—Br。

Six stilbene derivatives were synthesized by Heck reaction with yields of 68% - 84%. The influence of the reactant structure on the yield of the Heck reaction was investigated. The optimal results were obtained at 120℃ reaction temperature with a DMF and Et3N mixture（2： 1, V/V） as the solvent. It was also found that the yield decreased with decrease of the electron density on the double bond of the molecule （4-methylstyrene 〉 styrene 〉 4-vinyl pyridine） ; the reactivity of the halogen was in the order of NO2-Ar-Br 〉 H-Ar-Br 〉 CH3-Ar-Br.