Pd-Catalyzed Reduction of Aldehydes to Alcohols Using Formic Acid as the Hydrogen Donor

Abstract

Facile and selective reduction of aromatic aldehydes as well as aliphatic aldehydes to alcohols was achieved using formic acid as the hydrogen donor in the presence of a catalytic amount of Pd(OAc)₂ and Cy₃P. It was found that both hydrogen atoms in the formic acid molecule can serve as the hydride source.

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GRAPHICAL ABSTRACT

Keywords:

• Aldehydes
• formic acid
• hydrogen transfer reduction
• palladium-catalyzed
• reduction

ACKNOWLEDGMENTS

Z. T. thanks the National Science Foundation of China (No. 21072051), the NCET Program (NCET-09-0334), and the Fundamental Research Funds for the Central Universities, Hunan University for financial support. J.-C. S. thanks the National Science Foundation of China (No. 20971023) for financial support.

Notes

^a Reaction conditions: under N₂, benzaldehyde (1.0 mmol), Pd catalyst (0.05 mmol), ligand (0.075 mmol), and solvent (1.0 mL) were stirred at room temperature for 15 min, H₂O (4 equiv) and HCO₂H (10 equiv) were injected, and the reaction was heated at 90 °C for 18 h.

^b Yields are determined by GC.

^a Reaction conditions: under N₂, aldehyde (1.0 mmol), Pd(OAc)₂ (0.05 mmol), PCy₃ (0.075 mmol), and dioxane (1.0 mL) were stirred at room temperature for 15 min, H₂O (4 equiv) and HCO₂H (10 equiv) were injected, and the reaction was heated at 90 °C (18 h for aromatic aldehydes, 6 h for aliphatic aldehydes).

^b Isolated yields.