A K-arylacetylide complex for catalytic terminal alkyne functionalization using KO^tBu as a precatalyst

Area of Science:

• Organic Chemistry
• Catalysis
• Organometallic Chemistry

Background:

• Terminal alkynes are versatile building blocks in organic synthesis.
• Existing methods for alkyne dimerization often require transition metal catalysts.
• Developing metal-free catalytic systems is crucial for sustainable chemistry.

Purpose of the Study:

• To develop a transition metal-free catalytic method for terminal alkyne functionalization.
• To achieve selective homo- and hetero-dimerization of alkynes and nitriles.
• To elucidate the reaction mechanism.

Main Methods:

• Catalytic terminal alkyne functionalization using a novel metal-free system.
• Stoichiometric reactions to isolate and characterize key intermediates.
• X-ray crystallography for structural determination of the organometallic complex.

Main Results:

• Successful E-selective alkyne-alkyne homo-dimerization.
• Selective head-to-tail alkyne-nitrile hetero-dimerization.
• Isolation and characterization of a K-arylacetylide complex.
• Evidence for an ionic reaction mechanism.

Conclusions:

• A new, efficient, and metal-free catalytic system for alkyne dimerization has been established.
• The methodology allows for selective formation of diverse coupled products.
• The reaction proceeds via an ionic mechanism involving a key organometallic intermediate.