Copper-catalyzed remote double functionalization of allenynes.

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Addition reactions to unsaturated carbon-carbon bonds present challenges in controlling chemo-, regio-, and stereo-selectivity.
• The reactivity of readily available conjugated allenynes remains largely unexplored.
• Developing selective functionalization methods for allenynes is crucial for synthetic chemistry.

Purpose of the Study:

• To develop the first copper-catalyzed 2,5-hydrofunctionalization and 2,5-difunctionalization of allenynes.
• To provide facile access to versatile conjugated vinylic allenes featuring a carbon-boron (C-B) or carbon-silicon (C-Si) bond.
• To establish a mild protocol with a broad substrate scope for allenynes.

Main Methods:

• Copper-catalyzed reaction utilizing allenynes as substrates.
• Introduction of boron or silicon moieties via hydrofunctionalization or difunctionalization.
• Exploration of reaction conditions to achieve high selectivity and functional group tolerance.

Main Results:

• Successful development of a copper-catalyzed 2,5-hydrofunctionalization and 2,5-difunctionalization of allenynes.
• Synthesis of versatile conjugated vinylic allenes bearing C-B or C-Si bonds under mild conditions.
• Demonstration of a broad substrate scope, tolerating various synthetically useful functional groups.

Conclusions:

• The developed protocol offers an efficient and selective method for functionalizing allenynes.
• The resulting vinylic allenes serve as valuable platform molecules for synthesizing complex structures.
• Enables efficient access to monocyclic, bicyclic, and highly functionalized allene compounds.