Iodine(III) Reagents in Radical Chemistry

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Radical Chemistry

Background:

• Hypervalent iodine(III) compounds exhibit significant electrophilicity and radical reactivity.
• These reagents serve as valuable synthons for constructing diverse chemical bonds, including C-CF3, C-Rf, and C-N3.
• Their application in radical chemistry has expanded significantly over the past decades.

Purpose of the Study:

• To focus on the radical reactivity of hypervalent iodine(III) compounds.
• To explore the use of these reagents in generating carbon and heteroatom radicals.
• To investigate transition metal-free radical generation methods and their synthetic applications.

Main Methods:

• Single electron reduction of hypervalent iodine(III) reagents using sodium 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPONa).
• Radical generation via thermal or light-mediated homolysis of hypervalent iodine(III) compounds.
• Application of generated radicals in functionalization of alkanes, alkenes, arenes, and alkynes.

Main Results:

• Successful generation of trifluoromethyl, perfluoroalkyl, azidyl, and aryl radicals using hypervalent iodine(III) reagents.
• Demonstration of vicinal trifluoromethylation, azidation, and arylation of alkenes and arenes.
• Development of atom-economical difunctionalization of alkynes using cyano or perfluoroalkyl iodonium triflate salts.

Conclusions:

• Hypervalent iodine(III) compounds are powerful tools for radical-mediated organic synthesis.
• Transition metal-free radical generation offers a clean and efficient synthetic approach.
• Continued development of hypervalent iodine(III) reagents enhances their utility in complex molecule synthesis.