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This paper describes a general method for the synthesis and the isolation of novel 2, or 3-halopyridin-4-yl-boronic acids and esters 12–14, 18–20. These compounds are prepared taking in account a regioselective halogen–metal exchange using nBuLi or directed ortho-metalation using LDA and subsequent quenching with triisopropylborate starting from appropriate mono or dihalopyridines. All substrates studied to date provided a single regioisomeric boronic acid or ester product. Additionally, these compounds have been found to undergo Pd-catalysed coupling with a range of arylhalides and authorise a strategy to produce new pyridines libraries. [Copyright &y& Elsevier]

This paper describes a general method for the synthesis and the isolation of novel 2,4, or 5-halopyridin-3-yl-boronic acids and esters 4, 7, 10, 13, 15. These compounds are prepared taking into account a regioselective halogen–metal exchange using nBuLi or a regioselective ortho-lithiation using lithium diisopropylamide and subsequent quenching with triisopropylborate starting from appropriate mono or dihalopyridines. All substrates studied to date provided a single regioisomeric boronic acid or ester product. Additionally, these compounds have been found to undergo Pd-catalyzed coupling with a range of arylhalides and authorize a strategy to produce new pyridines libraries. [Copyright &y& Elsevier]