The Meyers synthesis of biaryls and Related reactions

followed by reaction with 2-amino-2-methyl-l-propanol (452) to give amide 

Somewhat different approach to the synthesis of orf/jo-substituted biaryls was reported by Julia and coworkers [48]. They found that tert-butylsulfonyl group can be replaced by aryl-carbanions originated from Grignard reagents in Ni(acac)2-catalysed process with formation of biaryls in moderate to high yields. Aryl-tert-butylsulfones are readily obtained by quenching the aryllithiums with di-tert-butyl disulfide, followed 

Since tert-butylsulfone group acts as strong director of ort/io-lithiation, the Julia s method can be useful in the synthesis of various ori/jo-substituted biaryls. Finally, arenes such as pyridine do not require the presence of electron-withdrawing substituent for the reaction with nucleophiles. Pyridines react with aryllithiums at 2-position, which is electrophilic, via nucleophilic addition, to give the respective 2-arylpyridines (Chichibabin reaction manner). In this fashion, the reaction of lithiated ferrocene with pyridine results in formation of a-pyridylferrocene in 24% yield [49]. 

Diaryliodonium salts and other hypervalent iodine compounds in the synthesis of biaryls 

Aryliodoninm salts, Aral X [50], and some other hypervalent aryliodonium compounds take a part in further important alternative cross-coupling reactions with arylboronic acids [51], aryltrifluoroborates [52], triarylbismuth(V) compounds [53], and diaryltellurium dichlorides [54] to afford biaryls in good to excellent yields. For example, hypervalent iodine compoimd 466, readily produced from 2-iodobenzoic acid, reacts with arylboronic acids in palladium-catalysed process in Suzuki-Miyaura-fashion to give the 2-arylbenzoic acids in high yields [51], Table 12. 

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