Chalcogen Bonding Activates [1.1.1]Propellane: Constructing Spiro[3.3]heptanes via Cyclobutyl Insertion into...

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Chalcogen bonding catalysis is a new synthetic platform.
• Activation of C-C σ-bonds by chalcogen bonding remains a challenge.
• Previous methods using transition metals were ineffective for [1.1.1]propellane activation.

Purpose of the Study:

• To explore the activation of C-C σ-bonds in [1.1.1]propellane using chalcogen bonding.
• To develop a novel method for synthesizing spiro[3.3]heptanes.
• To overcome limitations of existing catalytic systems.

Main Methods:

• Utilizing chalcogen bonding catalysts to activate the C-C σ-bond of [1.1.1]propellane.
• Facilitating the insertion of a cyclobutyl moiety into cyclopropenones.
• Investigating the reaction mechanism, including a dual catalysis mode.

Main Results:

• Successful activation of the C-C σ-bond of [1.1.1]propellane by chalcogen bonding.
• Efficient synthesis of spiro[3.3]heptanes via insertion into cyclopropenones.
• High efficiency with reactions completed in minutes at low catalyst loading (2.5 mol %) and mild temperatures (0 °C to room temperature).

Conclusions:

• Chalcogen bonding can effectively activate robust C-C σ-bonds, previously a significant hurdle.
• This work establishes a new synthetic route to spiro[3.3]heptanes using main-group catalysis.
• The developed method offers a highly efficient and mild alternative to traditional transition-metal catalysis for [1.1.1]propellane functionalization.