Efficient catalytic transfer hydrogenation reactions of carbonyl compounds by Ni(II)-diphosphine complexes

Abstract

The catalytic transfer hydrogenation reactions of a series of aromatic and aliphatic carbonyl compounds were investigated using divalent Ni(II)-diphosphine complexes, [L₂NiCl₂] (where L₂ = 1,1-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,1-bis(diphenylphosphino)ferrocene (dppf), and N-butyl-N-(diphenylphosphino)-1,1-diphenylphosphinamine (dppba)). This is a single-step reaction in the presence of potassium hydroxide and isopropyl alcohol to afford the corresponding alcohols. This protocol tolerates other sensitive functional groups like olefinic double bonds and also achieves high chemoselectivity. All the reactions were monitored by GC and GC–MS. The plausible mechanism is also discussed. The method reported in the present article is simple, cost-effective, and provides excellent conversions. Nickel-diphosphine complexes appear as a potential alternative to expensive transition metal complexes.

Graphical Abstract

Keywords:

• Nickel(II)-diphosphine complex
• catalytic transfer hydrogenation
• carbonyl compounds
• alcohols

Acknowledgements

Dr. Venkatesh Sadhana thanks CSIR, India for the Junior Research Fellowship. We also thank DST-VIT-FIST for NMR, VIT-SIF for GC-MS and other instrumentation facilities.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Dr ASRK is highly grateful to CSIR, India (Scheme No. 01/2541/11-EMR-II) for the financial support.