Palladium-catalyzed sonogashira and hiyama reactions using phosphine-free hydrazone ligands.

Takashi Mino, Yoshiaki Shirae, Takeshi Saito, Masami Sakamoto, Tsutomu Fujita

Index: J. Org. Chem. 71(25) , 9499-502, (2006)

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Abstract

Palladium/copper-catalyzed Sonogashira cross-coupling reaction of aryl halides with a variety of terminal alkynes under amine-free conditions in dimethylformamide (DMF) at 80 degrees C gave internal arylated alkynes using PdCl2(MeCN)2 with phosphine-free hydrazone 2a as a ligand and CuI as the cocatalyst in good yields. We also found PdCl2/hydrazone ligand 1d in PhMe at 80 degrees C was a phosphine-free efficient catalyst system for a Hiyama cross-coupling reaction of aryl bromides with aryl(trialkoxy)silanes in good yields.