Synthesis of benzene- and pyridinediboronic acids via organotin compounds

1,4- and 1,3-Bis(trimethylstannyl)benzenes as well as 2,5- and 2,6-bis(trimethylstannyl)pyridines react with borane in THF to give intermediates which on hydrolysis lead to benzene- and pyridinediboronic acids in 79-83% yield. While oxidation of the benzenediboronic acids with alkaline hydrogen peroxide gives the corresponding 1,3- and 1,4-dihydroxybenzenes, the pyridinediboronic acids lead via a double Suzuki reaction with 4-iodoanisole to 2,5- and 2,6-bis(4-methoxyphenyl)-pyridines and react with pinacol to give the corresponding pyridine-2,5-pinacol and pyridine-2,6-pinacol diboronic esters.