Copper-Catalyzed Three-Component Synthesis of Highly Substituted Morpholines

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Morpholines are prevalent heterocyclic scaffolds in pharmaceuticals and natural products.
• Efficient synthetic routes to highly substituted morpholines are crucial for drug discovery and development.
• Existing methods often lack broad substrate scope or require protecting groups.

Purpose of the Study:

• To develop a novel, efficient, and protecting-group-free synthesis of highly substituted morpholines.
• To explore the scope and limitations of the developed three-component reaction.
• To demonstrate the utility of the synthesized morpholines through further transformations.

Main Methods:

• Copper-catalyzed three-component reaction of amino alcohols, aldehydes, and diazomalonates.
• Utilized a broad range of substituted aldehydes and various vicinal amino alcohols.
• Investigated light-mediated stereochemical editing for epimerization.
• Demonstrated subsequent functionalization of the unprotected morpholine products.

Main Results:

• Successfully synthesized unprotected, highly substituted morpholines in good yields.
• The reaction demonstrated broad substrate scope for both aldehydes and amino alcohols.
• Achieved stereochemical control through light-mediated epimerization.
• The obtained morpholines were readily elaborated into more complex structures.

Conclusions:

• A versatile and efficient copper-catalyzed three-component reaction for synthesizing highly substituted morpholines has been established.
• The methodology offers a protecting-group-free approach, simplifying synthetic pathways.
• The developed method provides access to diverse morpholine derivatives with potential applications in medicinal chemistry.