Heteroarene derivatives, palladium-catalyzed

A novel and efficient palladium-catalyzed direct diheteroarylation of 1,2-dichlorop erfluorocyclopentene with a variety of heteroarenes has recently been reported, giving rise to l,2-di(hetaryl)perfluorocyclopentene photochromic compounds 102. The reaction occurs with thiazoles, thiophenes, or furan derivatives and tolerates varions substituents [112] (Scheme 37). 

Although the majority of direct arylations have been catalyzed by palladium, rhodium, and ruthenium, some additional studies have also focused on direct arylations catalyzed by first-row metals, such as iron and copper. For example, an iron-catalyzed direct arylation reaction between arylzinc reagents and 2-arylpyridine derivatives has been reported (Equation 19.146). Several direct couplings of heteroarenes with aryl halides (Equation 19.147) or hypervalent iodine reagents ° catalyzed by copper halides have also been reported. 

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