Catalytic Asymmetric Metallocyclopropanation Reactions Using Chloroform as a Carbyne Equivalent

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Catalysis

Background:

• Stereochemically complex, sp3-rich rings are crucial in drug discovery for improving physicochemical properties.
• Cyclopropanes offer unique 3D structures and metabolic stability, making them desirable drug scaffolds.
• Existing catalytic enantioselective cyclopropanation methods often rely on energetic reagents and limited carbene precursors.

Purpose of the Study:

• To develop a novel catalytic asymmetric cyclopropanation reaction.
• To utilize chloroform as a methylidyne equivalent for cyclopropane synthesis.
• To enable the synthesis of diverse, enantioenriched cyclopropane derivatives.

Main Methods:

• Employing a catalytic asymmetric cyclopropanation reaction with chloroform and zinc.
• Generating metallocyclopropane intermediates.
• Utilizing a telescoped process for further functionalization of cyclopropanes.

Main Results:

• Successful synthesis of halo-, aryl-, allyl-, alkynyl-, and vinyl-substituted cyclopropanes in high enantiomeric purity.
• Demonstration of high cis diastereoselectivity controlled by ligand design.
• Application in parallel synthesis of enantioenriched 1,2-diarylcyclopropanes with pharmaceutical relevance.

Conclusions:

• The developed method provides a versatile and efficient route to complex cyclopropanes.
• The reaction overcomes limitations of previous cyclopropanation techniques.
• The synthesized cyclopropanes are valuable building blocks for drug discovery and parallel synthesis.