Sonogashira coupling using bulky palladium-phenanthryl imidazolium carbene catalysis

Y Ma, C Song, W Jiang, Q Wu, Y Wang, X Liu…

Index: Ma, Yudao; Song, Chun; Jiang, Wei; Wu, Quansheng; Wang, Yong; Liu, Xueying; Andrus, Merritt B. Organic Letters, 2003 , vol. 5, # 18 p. 3317 - 3319

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Citation Number: 112

Abstract

Bulky phenanthracenyl imidazolium-derived carbene ligands were investigated for copper- free Sonogashira coupling with terminal acetylenes. Aryl bromides and iodides gave coupled products in excellent yields from the Pd (PPh3) 2Cl2 complex with potassium t- butoxide and 18-crown-6 in THF. A remarkable dependence on the size of the ligand was found. The highest yields were obtained with the bulky 2, 9-dicyclohexyl-10-phenanthryl ...