Abstract

ABONIA, Rodrigo  and  GARCIA, Andres C.. Using a warm dioxane/MeOH/NaBH₄ mixture as convenient medium for the selective chemical reduction of the C=C double bond in α,β-unsaturated systems. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2021, vol.45, n.177, pp.1232-1245.  Epub Feb 21, 2022. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.1465.

Diversely substituted Knoevenagel products were subjected to reduction with NaBH4 in MeOH/p-dioxane solution at 70 oC. Selectively reduction of their C=C double bond was achieved in all cases. Reduction conditions tolerated a variety of functional groups although simple aldolic or Claisen-Schmidt products showed to be less selective toward C=C reduction and on the contrary C=O bond was reduced under these reaction conditions. Additionally, selectivity of the NaBH4-mediated chemical reduction was compared with the classical Raney-Nickel-mediated catalytic hydrogenation in order to find similarities and differences. Moreover, trying to explain the selective NaBH4-mediated reductive process a plausible mechanistic pathway was proposed in this regard.

Keywords : Chalcones; Knoevenagel products; α,β-Unsaturated systems; Selective reductions; NaBH₄-mediate reductions; Catalytic hydrogenation.

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