Sonogashira cross-coupling in a designer ionic liquid (IL) without copper, external base, or additive, and with recycling and reuse of the IL

Application of a piperidine-appended dimethyl-imidazolium-NTf2 ionic liquid as dual solvent and base in the Sonogashira cross-coupling reaction of aryl-iodides with terminal acetylenes under mild conditions has been demonstrated. The method employs PdCl2(PPh3)2 without copper and external base. It is applicable to the synthesis of SF5-substituted diaryl- and aryl-alkyl-acetylenes, and can also be utilized for efficient homo-coupling of terminal acetylenes under aerobic conditions. The potential for recycling and reuse of this designer-IL offers an added advantage.