Mesoionic Carbene-Catalyzed Formyl Alkylation of Aldehydes

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Ketones are vital functional groups in organic synthesis with widespread applications.
• Existing methods for ketone synthesis often require harsh conditions or specific activators.

Purpose of the Study:

• To develop a novel, metal-free catalytic method for synthesizing ketones.
• To enable the coupling of aldehydes with unactivated alkyl halides, including primary and secondary ones.

Main Methods:

• Mesoionic carbene (MIC) catalysis was employed.
• Deprotonated Breslow intermediates were generated from MICs to act as electron donors.
• Single-electron reduction of alkyl halides was induced by the MIC-derived intermediates.

Main Results:

• A mild and efficient coupling reaction between aldehydes and alkyl halides was established.
• The reaction demonstrated a broad substrate scope, tolerating various functional groups.
• Diverse simple ketones and complex bioactive molecules were synthesized, including through late-stage functionalization.

Conclusions:

• The developed MIC-catalyzed method offers a versatile and mild approach for ketone synthesis.
• This metal-free strategy expands the toolkit for constructing ketones and functionalizing complex molecules.