Ortho-Carborane-Supported Hypervalent Iodine(III) Reagents: A Scaffold for Enhanced Oxidative Capability

Area of Science:

• Organometallic Chemistry
• Hypervalent Iodine Chemistry
• Boron Chemistry

Background:

• Hypervalent iodine(III) compounds are versatile reagents in organic synthesis.
• Aryl-iodine(III) compounds (Ar-IL2) are well-established but have limitations in reactivity.
• Carboranes offer unique electronic and steric properties for stabilizing reactive species.

Purpose of the Study:

• To synthesize and characterize novel C-bound ortho-carborane-supported hypervalent iodine(III) species (oCb-IL2).
• To evaluate the reactivity of these new oCb-IL2 compounds compared to traditional Ar-IL2 compounds.
• To explore potential new synthetic applications driven by enhanced reactivity.

Main Methods:

• Synthesis of ortho-carborane-supported iodine(III) complexes.
• Structural characterization using X-ray crystallography for key examples.
• Computational studies (e.g., DFT) to understand electronic properties and reactivity.
• Reactivity studies with various substrates, including trimethylsilyl fluoride.

Main Results:

• Successful synthesis of the first C-bound ortho-carborane-supported hypervalent iodine(III) species, denoted as oCb-IL2 (L = F, OTf).
• Structural verification of two oCb-IF2 examples.
• Theoretical calculations and initial synthetic observations indicate higher reactivity for oCb-IL2 compared to Ar-IL2 compounds.
• Demonstration of an unprecedented oxidative demethylation of trimethylsilyl fluoride.

Conclusions:

• The development of oCb-IL2 compounds represents a significant advancement in hypervalent iodine chemistry.
• These novel compounds exhibit superior reactivity, expanding the scope of accessible oxidative transformations.
• oCb-IL2 reagents offer a promising alternative for oxidizing substrates that are inert to conventional Ar-IL2 reagents.