Electrochemical Lactonization Enabled by Unusual Shono-Type Oxidation from Functionalized Benzoic Acids

Area of Science:

• Organic Chemistry
• Electrochemistry
• Synthetic Methodology

Background:

• Lactones are important structural motifs in numerous natural products and pharmaceuticals.
• Traditional lactone synthesis often requires harsh conditions, expensive metals, or stoichiometric oxidants.
• Electrochemical methods offer a sustainable alternative for organic synthesis.

Purpose of the Study:

• To develop a novel, metal- and oxidant-free electrochemical method for lactone synthesis.
• To achieve lactonization via direct C(sp3)-H functionalization.
• To demonstrate the broad applicability and synthetic utility of the developed methodology.

Main Methods:

• Electrochemical oxidation for C(sp3)-H functionalization.
• Metal- and oxidant-free reaction conditions.
• Mechanistic investigations using control experiments and cyclic voltammetry (CV).

Main Results:

• Efficient synthesis of various lactones was achieved through electrochemical lactonization.
• The method demonstrated high functional group tolerance and scalability (gram-scale reactions).
• Mechanistic studies supported an intramolecular hydrogen atom transfer (HAT) and oxidative cyclization pathway, realizing an unusual Shono-type oxidation.

Conclusions:

• A novel and efficient electrochemical strategy for lactone synthesis via C(sp3)-H functionalization has been established.
• The metal- and oxidant-free approach provides a sustainable and practical route to diverse lactones.
• The methodology enables an unusual Shono-type oxidation, expanding the scope of electrochemical organic synthesis.