Triazene as the Directing Group Achieving Highly Ortho-Selective Diborylation and Sequential Functionalization.

Area of Science:

• Organometallic Chemistry
• Synthetic Organic Chemistry
• Catalysis

Background:

• Aromatic triazenes are versatile precursors in organic synthesis.
• Regioselective C-H functionalization remains a key challenge in synthetic chemistry.
• Developing efficient catalytic systems for borylation is crucial for accessing valuable organic building blocks.

Purpose of the Study:

• To develop a novel regioselective ortho,ortho'-diborylation method for aromatic triazenes.
• To explore the catalytic activity of [Ir(OMe)(cod)]2 in the absence of additional ligands.
• To demonstrate the utility of the synthesized diboronate esters in further chemical transformations.

Main Methods:

• Catalytic diborylation of aromatic triazenes using [Ir(OMe)(cod)]2.
• X-ray crystallography to elucidate the structure of key intermediates.
• One-pot sequential modifications of the synthesized diboronate esters.

Main Results:

• Near-quantitative yields of regioselective ortho,ortho'-diborylation were achieved.
• Aromatic triazenes were found to act as both substrates and ligands.
• Monoborylation products were observed to facilitate subsequent diborylation.
• Synthesized diboronate esters were successfully transformed via directing group removal.

Conclusions:

• The developed method provides an efficient route to ortho,ortho'-diborylated aromatic triazenes.
• The study highlights the dual role of aromatic triazenes as substrates and ligands.
• One-pot sequential modifications offer a streamlined approach to densely functionalized arenes.