Tandem Imine Formation and Alkyne Metathesis Enabled by Catalyst Choice

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry

Background:

• Molecular ladders represent complex architectures with potential applications in nanotechnology and materials science.
• Efficient synthetic routes are crucial for accessing these intricate structures.

Purpose of the Study:

• To develop a one-pot synthesis for a three-rung molecular ladder.
• To investigate the efficacy of specific catalysts in alkyne metathesis for ladder formation.
• To explore the stability and reactivity of the synthesized molecular ladder.

Main Methods:

• One-pot synthesis combining imine condensation and alkyne metathesis.
• Catalytic screening using catalysts VI and III for imine-bearing substrates.
• Investigation of catalyst VI deactivation pathways (hydrolysis, ligand exchange).
• Demonstration of one-pot assembly and disassembly of the molecular ladder.

Main Results:

• Successful one-pot synthesis of three-rung molecular ladder 8 via tandem imine condensation and alkyne metathesis.
• Catalyst VI effectively catalyzed the alkyne metathesis of imine-bearing substrate 7, unlike catalyst III.
• Catalyst VI showed susceptibility to deactivation via hydrolysis and ligand exchange.
• The molecular ladder 8 could be assembled and disassembled in one pot, with and without a Lewis acid.

Conclusions:

• A streamlined synthetic strategy for constructing molecular ladders has been established.
• Catalyst VI is a viable catalyst for imine-involved alkyne metathesis, but its stability requires consideration.
• The reversible nature of the ladder formation offers potential for dynamic molecular systems.