Cooperative Effect of Carborane and Pyridine in the Reaction of Carboranyl Alcohols with Thionyl Chloride: Halogenation versus Oxidation

Thionyl chloride (SOCl<sub>2</sub>) acts as halogenation reagent in its reaction with 1-[phenyl(hydroxy)methyl]-2-R-1,2-dicarba-<i>closo</i>-dodecaborane <b>1a</b>,<b>b</b> but unexpectedly behaves as an oxidant for 1-[2′-pyridyl(hydroxy)methyl]-2-R-1,2-dicarba-<i>closo</i>-dodecaboranes <b>2a</b>,<b>b</b>. The synthesis and characterization of all new compounds, including structure determinations of <b>1a</b>, <b>2a</b>, 1-[phenyl(chloro)methyl]-2-methyl-1,2-dicarba-<i>closo</i>-dodecaborane <b>3a</b>, and 1-[2′-pyridyl(oxo)methyl]-2-methyl-1,2-dicarba-<i>closo</i>-dodecaboranes <b>4a</b> are reported and the possible pathways are discussed.