Enhancing the efficiency of the ruthenium catalysts in the reductive amination without an external hydrogen source

Abstract

Catalytic reductive reactions are essential for laboratory and industrial-scale organic synthesis. However, the nowadays trend is the development of new, progressively more complicated reducing systems, which hinders the application of such highly efficient approaches in practice. Another way to achieve highly active systems is enhancing the activity of the earlier developed catalysts with simple structures. Herein we demonstrated a significant increase (up to 15-fold) in the catalytic activity of ruthenium catalysts in the reductive amination after the addition of iodide to the reaction mixture. Catalyst turnover numbers up to 9000 were achieved with preparative yields of the products. The plausible reasons for this effect were formulated.