Vinyl Carbocations Generated under Basic Conditions and Their Intramolecular C-H Insertion Reactions

Area of Science:

• Organic Chemistry
• Catalysis
• Reaction Mechanisms

Background:

• Vinyl carbocations are typically high-energy intermediates.
• Generating and controlling these species under basic conditions is challenging.
• Intramolecular C-H insertion reactions offer efficient synthetic pathways.

Purpose of the Study:

• To report the surprising generation of high-energy vinyl carbocations under strongly basic conditions.
• To demonstrate their utility in intramolecular sp3 C-H insertion reactions.
• To explore the application of this novel methodology to heteroatom-containing substrates.

Main Methods:

• Utilizing lithium hexamethyldisilazide as a strong base.
• Employing triphenylmethylium tetrakis(pentafluorophenyl)borate as a catalyst.
• Investigating the formation of catalytically active lithium species.

Main Results:

• Successful generation of high-energy vinyl carbocations under strongly basic conditions.
• Demonstration of intramolecular sp3 C-H insertion reactions catalyzed by weakly coordinating anion salts.
• Expansion of vinyl cation C-H insertion reactions to heteroatom-containing substrates.

Conclusions:

• A novel method for generating vinyl carbocations under basic conditions has been developed.
• This approach enables efficient intramolecular C-H insertion reactions.
• The methodology shows promise for synthesizing complex molecules containing heteroatoms.