Palladium-catalysed cross-coupling of lithium acetylides

The incorporation of alkynes into organic molecules is one of the most valuable transformations for the formation of C–C bonds and provides a versatile handle for further modifications. The Sonogashira cross-coupling of acetylenes holds a prominent position among the suite of catalytic cross-coupling reactions that are key to modern synthesis. Here we present a method that is complementary to the Sonogashira reaction, demonstrating cross-coupling of lithium acetylides with aryl bromides. The reactions take place under ambient conditions with short reaction times, affording the corresponding aryl acetylenes in good to excellent yields while displaying a remarkable functional group tolerance for an organolithium reaction, allowing the presence of a variety of organolithium-sensitive carbonyl functionalities. This developed cross-coupling methodology offers ample opportunities to access a wide variety of acetylenes, as is illustrated by the facile preparation of key intermediates for chemical biology and optoelectronic materials. [Figure not available: see fulltext.]