Cross-coupling reactions on azoles with two and more heteroatoms

Recent progress in the field of transition-metal-catalyzed cross-coupling reactions on various azole systems is summarized. Most important C-C- and C-X-bond formation methodologies (Negishi, Suzuki-Miyaura, Stille, Kumada-Corriu-Tamao, Hiyama, Sonogashira, Heck, C-H activation) are reviewed and discussed for the imidazole, oxazole, thiazole, pyrazole, isoxazole, and isothiazole system, as well as for azoles with more than two heteroatoms. This review covers the literature that appeared in the past ten years up to the end of 2005 with corresponding azoles used either as metal organyl or halide (including triflates and some other less frequently applied leaving groups); literature describing azole structures only as ligands was not included. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).