Highly efficient copper(0)-catalyzed Suzuki-Miyaura cross-coupling reactions in reusable PEG-400

Readily available copper powder with K2CO3 as the base was extremely effective catalyst for Suzuki-Miyaura coupling reaction performed in PEG-400, which afforded almost quantitative coupling products of aryl iodides. Using iodine as additive, coupling products of aryl bromides or chlorides could be obtained with moderate to good yields.