Dialkyl (3-pyridyl) boranes

Dialkyl (3-pyridyl) boranes (2) were synthesized by the iodination of lithium trialkyl (3-pyridyl) borates, prepared from trialkylboranes and 3-lithiopyridine. Although 2 was resistant to quaternization or ate-complex formation, betaines (4b-e) were obtained by the reaction of 2a with cyanide ion and alkylating agents in high yields. Further, protonolysis of 2a with propionic acid gave 3-pyridylboronic acid (5). Proton and carbon-13 nuclear magnetic resonance data for 2a, b and 4b are presented.