Synthesis, NMR characterization, and a simple application of lithium borotritide

LiBH4 is a powerful and selective reagent for regiospecific reduction reactions. A simple synthesis of LiB3H4 at near theoretical specific radioactivity is reported. The authors have treated Li3H synthesized from tritium gas (3H2, ∼98%) with BBr3 to produce LiB3H4 (specific activity = 4120 GBq/mmol = 110 Ci/mmol. The maximum theoretical specific activity of LiB3H4 is 4252 GBq/mmol = 115.04 Ci/mmol; 1 matom of 3H = 1063 GBq = 28.76 Ci.) The tritium labeling performance of the reagent was tested by an exemplary reduction of 2-naphthaldehyde to 2-naphthalenemethanol. LiB3H4 and the reduction products were characterized by a combination of 1H, 3H, and 11B NMR techniques, as appropriate. 35 refs., 1 fig