Decarboxylative Hydroalkylation of Alkynes

Area of Science:

• Organometallic Chemistry
• Radical Chemistry
• Organic Synthesis

Background:

• Traditional methods struggle with unactivated alkynes and C-H bonds.
• Selective radical additions are synthetically valuable.
• Organometallic catalysis offers new reactivity pathways.

Purpose of the Study:

• To develop a method for selective intermolecular addition of nucleophilic radicals to unactivated alkynes.
• To synthesize stereodefined functionalized olefins from carboxylic acids.
• To extend this methodology for direct vinylation of unactivated C-H bonds.

Main Methods:

• A sequence involving CO2 extrusion, nickel capture, and migratory insertion.
• Utilizing carboxylic acids as radical precursors.
• Employing hydrogen atom transfer for C-H bond functionalization.

Main Results:

• Selective intermolecular addition of nucleophilic radicals to terminal and internal alkynes.
• Generation of stereodefined functionalized olefins.
• Successful direct vinylation of unactivated C-H bonds.

Conclusions:

• The developed organometallic platform enables efficient synthesis of functionalized olefins.
• The methodology provides a route for direct C-H bond vinylation.
• A nickel-alkyl migratory insertion mechanism is proposed to be operative.