Transition Metal Catalyst-Free, Base-Promoted 1,2-Additions of Polyfluorophenylboronates to Aldehydes and Ketones

Area of Science:

• Organic Chemistry
• Organometallic Chemistry
• Synthetic Chemistry

Background:

• Transition metal catalysis is widely used for C-C bond formation.
• Developing metal-free alternatives is crucial for sustainability and cost-effectiveness.
• Polyfluoroaryl compounds offer unique electronic properties and applications.

Purpose of the Study:

• To develop a novel transition metal-free protocol for the 1,2-addition of polyfluoroaryl boronate esters to aldehydes and ketones.
• To synthesize secondary alcohols, tertiary alcohols, and ketones.
• To investigate the key factors influencing the reaction efficiency and scope.

Main Methods:

• Utilized polyfluoroaryl boronate esters and various aldehydes and ketones as starting materials.
• Employed a carbonate base with a potassium counterion (K+).
• Conducted control experiments and Density Functional Theory (DFT) calculations to elucidate the reaction mechanism.

Main Results:

• Achieved a novel transition metal-free 1,2-addition of polyfluoroaryl boronate esters to carbonyl compounds.
• Synthesized secondary alcohols, tertiary alcohols, and ketones with moderate to excellent yields.
• Identified ortho-F substituents and the K+ counterion as critical components for the reaction's success.
• Observed unique structural features including hydrogen bonding and arene-perfluoroarene interactions in the products.

Conclusions:

• The developed protocol offers a viable and efficient metal-free route for synthesizing polyfluoroaryl carbinols.
• The reaction benefits from readily available starting materials and a broad substrate scope.
• Understanding the role of substituents and counterions provides insights for further optimization of such reactions.