A copper-free Sonogashira coupling reaction in ionic liquids and its application to a microflow system for efficient catalyst recycling.

[reaction: see text] The PdCl2(PPh3)2-catalyzed Sonogashira coupling reaction, in good to high yields, was performed in an ionic liquid ([BMIm][PF6]) in the absence of a copper salt. The use of an ionic liquid allows for the facile separation and recycling of the catalyst. The application of the above reaction in a microflow system in conjunction with an IMM micromixer was also successful.