Facile Synthesis of Aminodiborane and Inorganic Butane Analogue NH<sub>3</sub>BH<sub>2</sub>NH<sub>2</sub>BH<sub>3</sub>

A new ambient-temperature, catalyst-free reaction between ammonia borane and tetrahydrofuran borane produces aminodiborane via the formation of a dihydrogen bond and subsequent molecular hydrogen elimination. The facile synthesis of aminodiborane will make this long-sought active chemical reagent readily available for both inorganic and organic reactions. From aminodiborane, an inorganic butane analogue, NH<sub>3</sub>BH<sub>2</sub>NH<sub>2</sub>BH<sub>3</sub>, was prepared, and its single-crystal structure displayed a gauche rather than an anti form conformation.