Sterically crowded 1,4-diiodobenzene as a precursor to difunctional hypervalent iodine compounds

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Hypervalent iodine (HVI) compounds with multiple iodine(III) centers are gaining interest.
• These compounds show promise as recyclable reagents, materials precursors, and Lewis acids.
• Steric hindrance and solubility are key challenges in developing multifunctional HVI compounds.

Purpose of the Study:

• To synthesize and characterize a novel, sterically hindered di-hypervalent iodine compound.
• To investigate the cyclization behavior of this compound under mild conditions.
• To explore the impact of bulky substituents on the solubility and properties of HVI compounds.

Main Methods:

• Synthesis of a bulky 1,4-di-iodobenzene precursor with para-tert-butylaryl substituents.
• Preparation of a di-hypervalent iodine compound (1,4-[I(OAc)2]2-2,3,5,6-Ar'4-C6).
• Cyclization of the di-hypervalent iodine compound to a dicyclic di-iodonium salt using trifluoroacetic acid.
• Single crystal X-ray diffraction analysis of the precursor and products.

Main Results:

• A novel di-hypervalent iodine compound (2) was successfully synthesized from a sterically hindered precursor (1).
• Compound 2 readily cyclized under mild conditions to form a dicyclic di-iodonium di-triflate salt (3).
• The para-tert-butyl groups enhanced solubility compared to other multifunctional HVI compounds.

Conclusions:

• Sterically encumbered hypervalent iodine compounds can undergo facile cyclization.
• The bulky substituents improve solubility, facilitating the handling and potential application of these HVI compounds.
• This work expands the scope of accessible multifunctional hypervalent iodine compounds for various chemical applications.