One-pot synthesis of 5,5 '-dibromo-2,2 '-dipyridylacetylene and its boronic acid derivative

Abstract

5,5'-Dibromo-2,2'-dipyridylacetylene was prepared from 2,5-dibromopyridine and (trimethylsilyl)acetylene via the new one-pot synthesis approach using a regioselective palladium-catalyzed coupling reaction with a 60% yield. Several protocols of lithium-halogen exchange were then attempted to synthesize 6,6'-(1,2-ethynediyl)bis[3-Pyridylboronic acid] from 5,5'-dibromo-2,2'-dipyridylacetylene. The former was successfully obtained with a 54% yield by a reverse addition method using toluene and THF and it showed potential as a useful building block for cross-coupling reactions in the formation of carbon-carbon bonds. (C) 2010 Elsevier Ltd. All rights reserved.