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Synfacts 2009(3): 0260-0260
DOI: 10.1055/s-0028-1087793
DOI: 10.1055/s-0028-1087793
Synthesis of Heterocycles
© Georg Thieme Verlag
Stuttgart ˙ New York
Pd-Catalyzed Direct Arylations of Heteroaromatics using Aryl Sulfonates
L. Ackermann*, A. Althammer, S. Fenner
Georg-August-Universität, Göttingen, Germany
Further Information
Publication History
Publication Date:
19 February 2009 (online)
Significance
Reported is a palladium-catalyzed direct arylation of heteroarenes (benzoxazole, oxazole, caffeine, 1,2,3-triazole) with aryl tosylates. The first examples of direct arylation using mesylates as arylating reagents are also described. This cross-coupling involves the use of Pd(OAc)2/X-Phos as a catalytic system and K2CO3 as a base. In the case of benzoxazole, the addition of a catalytic amount of t-BuCO2H improves the coupling. The scope of the reaction has been studied with electron-rich and electron-poor aryl tosylates and mesylates to give products in 58-99% yields. Single examples of an ortho-substituted aryl tosylate and an alkenyl tosylate were also described.