A Metal-Catalyzed Tandem 1,4-Benzodiazepine Synthesis Based on Two Hydrogen-Transfer Reactions

Starting from 2-aminobenzyl alcohols and 1,2-amino alcohols, 2,3,4,5-tetrahydro-1H-1,4-benzodiazepines (THBDZ) can be prepared through a one-pot ruthenium-catalyzed reaction encompassing two consecutive borrowing hydrogen cycles. First, benzyl alcohol oxidation, condensation with the amino alcohol, and imine reduction occurs. This is followed by oxidation of the other alcohol functionality and reductive cyclocondensation to give the TH-BDZ derivatives. A single catalyst does the entire job, with two molecules of water being the only waste product. Many new substituted 2,3,4,5-tetrahydro-1H-1,4-benzodiazepines have been prepared to demonstrate the versatility of this method, which can be used for the preparation of privileged scaffolds for drug discovery. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.