Nickel-catalyzed selective conversion of two different aldehydes to cross-coupled esters

Area of Science:

• Organic Chemistry
• Catalysis
• Green Chemistry

Background:

• Selective synthesis of esters from aldehydes is crucial in organic chemistry.
• Traditional methods often involve multiple steps and generate significant waste.
• Developing atom-efficient catalytic systems for aldehyde cross-coupling remains a challenge.

Purpose of the Study:

• To develop a novel catalytic method for the selective synthesis of cross-coupled esters from equimolar mixtures of aliphatic and aryl aldehydes.
• To investigate the scope and efficiency of the developed reaction.
• To elucidate the reaction mechanism, focusing on the role of the Ni(0)/NHC catalyst.

Main Methods:

• Utilized a Ni(0)/N-heterocyclic carbene (NHC) catalyst system.
• Employed equimolar mixtures of various aliphatic (primary, secondary, cyclic secondary, tertiary) and aryl aldehydes.
• Conducted mechanistic studies to probe the coordination behavior of aldehydes to the Ni(0) center.

Main Results:

• Achieved selective formation of a single cross-coupled ester product from mixed aldehyde feedstocks.
• Demonstrated broad applicability across diverse aliphatic and aryl aldehyde combinations.
• The reaction exhibited 100% atom efficiency and produced no chemical waste.
• Mechanistic studies revealed simultaneous coordination of two aldehydes to the Ni(0) catalyst as a key feature.

Conclusions:

• The developed Ni(0)/NHC-catalyzed reaction offers a highly efficient and selective route for synthesizing cross-coupled esters from aldehydes.
• The methodology aligns with green chemistry principles due to its high atom economy and zero-waste generation.
• The unique simultaneous dual aldehyde coordination mechanism provides new insights into nickel-catalyzed transformations.