Highly Selective Ring Expansion of Bicyclo[3.1.0]hexenes

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Accessing seven-membered carbocycles is challenging in organic synthesis.
• Bicyclo[3.1.0]hexenes are strained cyclic olefins.
• Terminal alkynes are versatile C2 building blocks.

Purpose of the Study:

• To develop a novel synthetic route to seven-membered carbocycles.
• To explore the utility of ruthenium-carbene catalysis in ring expansion reactions.
• To investigate the regioselectivity and substrate scope of the transformation.

Main Methods:

• Ring expansion of bicyclo[3.1.0]hexenes using terminal alkynes.
• Ruthenium-carbene (Ru-carbene) complex catalysis.
• Analysis of reaction products using NMR spectroscopy and mass spectrometry.

Main Results:

• A highly regioselective synthesis of seven-membered carbocycles was achieved.
• The reaction proceeds via a Ru-carbene-promoted ring expansion mechanism.
• The products possess both conjugated diene and cyclopropane moieties, enabling further functionalization.

Conclusions:

• This study presents an efficient method for constructing complex seven-membered carbocycles.
• The developed methodology offers a new pathway for accessing valuable cyclic scaffolds.
• The resulting products serve as versatile intermediates for subsequent chemical transformations.