Perosa Alvise, Tundo Pietro, Selva Maurizio, Zinovyev Sergei, Testa Alberto
Dipartimento di Scienze Ambientali dell'Universita Ca' Foscari, Consorzio Interuniversitario Nazionale "la Chimica per l'Ambiente", Dorsoduro 2137 - 30123 Venezia, Italy.
Org Biomol Chem. 2004 Aug 7;2(15):2249-52. doi: 10.1039/b406822j. Epub 2004 Jul 14.
The rate of the Pd/C catalyzed Heck coupling of Ar-I with CH(2)=CH-R is accelerated tenfold by the presence of Aliquat 336 (A336), a well known phase transfer catalyst, and an ionic liquid. Both when conducted in A336 as solvent, and in an isooctane/A336/aqueous triphasic mixture, the Heck reaction of aryl iodides with electron deficient olefins, catalyzed by Pd/C, proceeds with high yields and selectivity. When KOH is used instead of Et(3)N, selective formation of the biphenyl rather than the Heck product, is observed. Aryl bromides react more sluggishly, and only the more activated ones undergo the Heck reaction. In the absence of the olefin, aryl halides possessing an electron withdrawing group are reduced to the corresponding Ar-H.
在知名相转移催化剂Aliquat 336（A336）和离子液体存在的情况下，钯碳催化的芳基碘化物与CH(2)=CH-R的Heck偶联反应速率加快了十倍。无论是在A336作为溶剂的体系中，还是在异辛烷/A336/水的三相混合物中，钯碳催化的芳基碘化物与缺电子烯烃的Heck反应都能以高收率和选择性进行。当使用氢氧化钾代替三乙胺时，会观察到选择性生成联苯而非Heck产物。芳基溴化物的反应较为迟缓，只有活性较高的芳基溴化物会发生Heck反应。在没有烯烃的情况下，带有吸电子基团的芳基卤化物会被还原为相应的Ar-H。
