Anionic access to silylated and germylated binuclear heterocycles

Area of Science:

• Organometallic Chemistry
• Heterocyclic Chemistry
• Synthetic Methodology

Background:

• Anionic rearrangements offer unique pathways for constructing complex molecules.
• Silylated and germylated heterocycles are valuable building blocks in materials science and medicinal chemistry.
• Understanding the factors governing regioselectivity is crucial for synthetic control.

Purpose of the Study:

• To describe a novel anionic rearrangement for accessing silylated and germylated binuclear heterocycles.
• To investigate the mechanism and regioselectivity of this rearrangement with various aromatic and heteroaromatic substrates.
• To explore the influence of silicon substituents on ligand transfer selectivity and extend the methodology to germanium substrates.

Main Methods:

• Synthesis of silylated and germylated binuclear heterocycles via anionic rearrangement.
• Systematic variation of electron-rich and electron-poor aromatic/heteroaromatic substrates.
• Analysis of reaction products to determine regioselectivity and identify reaction pathways.
• Study of substituent effects on silicon and extension to germanium analogues.

Main Results:

• A simple access to silylated binuclear heterocycles was established through an original anionic rearrangement.
• Regioselectivity was found to follow previously proposed rules, demonstrating predictable control.
• The study revealed the effect of silicon substituents on ligand transfer selectivity.
• The chemistry was successfully extended to germylated substrates, with evidence of a hypervalent germanium intermediate.
• A novel reaction pathway involving LiCH2Cl elimination was observed for germanium, yielding unexpected benzo-oxa/aza germol-type products.

Conclusions:

• The described anionic rearrangement provides an efficient route to silylated and germylated heterocycles.
• The findings offer insights into the mechanistic aspects and regiochemical control of these transformations.
• The extension to germanium chemistry highlights new synthetic possibilities and unexpected reactivity patterns.