Water-soluble and reusable Ru-NHC catalyst for aqueous-phase transfer hydrogenation of quinolines with formic acid.

Babulal Maji, Anirban Bhandari, Rayantan Sadhukhan, Joyanta Choudhury

Dalton transactions (Cambridge, England : 2003) 2022 May 31

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Water-soluble Ru-NHC complexes were synthesized and their catalytic activity was tested in the transfer hydrogenation of quinoline-type N-heteroarenes using a formic acid/sodium formate buffer solution. The unique multifunctional features of the designed ligand within the catalyst backbone endowed it with excellent durability, reusability and compatibility with a simple aqueous-phase operation. Thus, it was possible to reuse as little as 0.25 mol% of the catalyst for three consecutive catalytic runs to provide an overall turnover number of around 900. A mechanistic investigation suggested that hydride generation was the rate-limiting step, whereas hydride transfer was relatively facile. Furthermore, computational studies supported that the reaction pathway was dominated by 1,4-hydride insertion at the N-heteroarene substrates.

Citation

Babulal Maji, Anirban Bhandari, Rayantan Sadhukhan, Joyanta Choudhury. Water-soluble and reusable Ru-NHC catalyst for aqueous-phase transfer hydrogenation of quinolines with formic acid. Dalton transactions (Cambridge, England : 2003). 2022 May 31;51(21):8258-8265