Reaction of Miscellaneous Aromatic Substrates

Benzodioxole has been found to undergo direct arylation at the 3-position selectively in the presence of Pd(OAc)2/PMe( Bu)2 and K2C03/Ag0Tf as catalyst and additive, respectively, in N,N-dimethylacetamide (DMA). While the mechanism of this reaction is not clear, a cationic ArPd(II) species seems to participate as the reactive intermediate (Equation 10.23) [40]. Interestingly, electron-deficient di- to pentafluorobenzenes couple directly with aryl halides (Equation 10.24) [41, 42]. 

Cyclopentadienyl anion as a reactive anionic aromatic substrate, which is generated in situ, undergoes perarylation on treatment with excess aryl halides to give penta-arylcyclopentadienes (Equation 10.27) [45, 46]. Di(tert butyl)phosphinylferro cene is also perphenylated by chlorobenzene (Equation 10.28) [47], but in this case a coordination-assisted mechanism seems to be operative. 

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