Highly strained heterocycles constructed from Boron-Boron multiple bonds and heavy chalcogens

The reactions of a diborene with elemental selenium or tellurium are shown to afford a diboraselenirane or diboratellurirane, respectively. These reactions are reminiscent of the sequestration of sub-valent oxygen and nitrogen in the formation of oxiranes and aziridines; however, such reactivity is not known between alkenes and the heavy chalcogens. While carbon is too electronegative to facilitate the reduction of elements of lower relative electronegativity, this is overcome by the highly reducing nature of the double bond in diborenes. The capacity of multiple bonds between boron to donate electron density is highlighted in a reaction where diboryne is shown to behave as nucleophile, attacking diarylditellurides in the formation of a diboratellurenium cations with aryltelluride anions.