Polychloroaromatic compounds lithiated by Bu n Li in THF react with several electrophilic agents of which aldehydes and epoxides seem to be the most promising from the preparative point of view.

The Suzuki cross coupling with phenylboronic acid in the presence of the Pd(OAc) 2 /K 3 PO 4 /DMF catalytic system was successful for aryl bromides and somewhat poorer for aryl chlorides. Addition of 1,3 bis(tetrazol 1 yl)benzene or its analogs lowered the yields of biaryls.

Hexachlorobenzene and 1,2,4,5 tetrachlorobenzene react with phenylboronic acid by a С-С cross coupling mechanism with a Pd(dba) 2 /P(Bu t ) 3 system (dba is dibenzylideneacetone) or palladium azole complexes as catalysts, or with organozinc compounds in the presence of Pd(PPh 3 ) 4 to afford substitution products of one or two chlorine atoms in moderate yields.

The reactions of di , tetra , and hexachlorobenzenes with phenylboronic acid in the pres ence of [Pd]-imidazolium salt-base as catalytic systems afford cross coupling products in moderate yields. The highest conversions are attained when imidazolium salts bearing bulky aromatic substituents are used and the reaction is carried out in the presence of alkali alkoxides containing H α atoms. Cross coupling is accompanied by hydrodechlorination of aromatic C-Cl bonds.

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