Facile synthesis of substituted alkynes by cyclopalladated ferrocenylimine catalyzed cross-coupling of arylboronic acids/esters with terminal alkynes

A highly efficient and convenient catalytic system for the cross-coupling reaction of arylboronic reagents with terminal alkynes was described by using cyclopalladated ferrocenylimine (I)/silver oxide as the catalyst at room temperature. This method provides the first examples of a palladacycle-catalyzed cross-coupling reaction of arylboronic acids/esters with terminal alkynes under mild conditions, and also a facile route for the synthesis of substituted alkynes with a low Pd loading of 1 mol-%. The substrates could be extended to electron-poor alkynes, for which the traditional Sonogashira reaction does not proceed. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).