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DOI: 10.1055/s-2005-921618
PEG-Supported Imidazolium Chloride for the Heck Reaction
L. Wang, Y. Zhang*, C. Xie, Y. Wang
Zhejiang university, Hangzhou, P. R. of China
Publikationsverlauf
Publikationsdatum:
22. November 2005 (online)
Significance
PEG-succinic acid 2 was prepared from poly(ethylene glycol) (PEG) 4000 and succinic anhydride. The preparation of PEG-supported 3-methyl-imidazolium chloride 3 ([PEGmim][Cl]) was accomplished by esterification of 1-(2-hydroxylethyl)-3-methylimidazolium chloride 1 with PEG-succinic acid 2. Using the Pd(OAc)2/[PEGmim][Cl] system, the Heck reaction of activated aryl chlorides with olefins proceeded under basic conditions at 160 ºC to afford the corresponding coupled products in 23-97% yield (8 entries). Aryl bromides also reacted with olefins under similar conditions to give the coupled products 91-97% yield (12 entries). The Pd(OAc)2/[PEGmim][Cl] catalytic system was recycled five times without loss of catalytic activity.