Synthesis of novel halopyridinylboronic acids and esters. Part 4: Halopyridin-2-yl-boronic acids and esters are stable, crystalline partners for classical Suzuki cross-coupling
This paper describes some methods for the synthesis and the isolation of novel 5 or 6-halopyridin-2-yl-boronic acids and esters 3, 4, 7. These compounds are prepared via a regioselective halogen-metal exchange using n-butyllithium and subsequent quenching with triisopropylborate starting from appropriate 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 arylhalides and authorise a strategy to produce new pyridines libraries.
Bouillon, Alexandre,Lancelot, Jean-Charles,Santos, Jana Sopkova De Oliveira,Collot, Valérie,Bovy, Philipppe R.,Rault, Sylvain