NaBH4 in N-methylpyrrolidone: a safe alternative for hydride displacement reaction

Enhanced reactivity of NaBH4 was observed as a solution in N-methylpyrrolidone (NMP). Thus, a simple protocol for debromination of alkyl bromide and sulfonate is devised with NMP as a key solvent. Also described is a new mixed borohydride system, NaBH4–LiOTf–NMP, which works as an alternative to NaBH3CN for the SN2 type displacement. No reports have ever revealed usefulness of NMP in borohydride reduction.