Leveraging In-Situ Formation of β-Silicon-Stabilized Vinyl Cations in Silylium-Ion Catalysis

• Applicant: Professor Dr. Martin Oestreich
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 554788926

The primary aim of this project is the regio- and diastereoselective bisfunctionalization of unactivated internal alkynes by the generation of ß-silicon-stabilized vinyl cations. Preliminary work has already shown the viability of this project through the bisfunctionalization of alkynes using S−Si reagents in a two-component reaction obtaining the desired products in good yields and with excellent regio- and diastereoselectivity. We now intend to expand upon this methodology through variation of both the nucleophilic part, to different atoms containing lone pairs, and the electrophilic part, to different group 14 elements. This will give access to a wide range of tetrasubstituted alkenes which can then be subjected to further chemoselective manipulations in a stereo-defined manner. Secondary to this, we have recently found that, in the presence of similar reagents, through the same ß-silicon-stabilized vinyl cations, alkynes and silylated allenes can be reacted in a formal cycloaddition reaction to form either cyclopentenes or cyclobutenes. Substitution on the allene determines whether the reaction goes by a (3+2) or (2+2) cycloaddition, and computational work has been performed to fully understand the mechanism of the former pathway. Our goal is to more fully explore this remarkable chemistry through reaction optimization and substrate scope investigation.

• DFG Programme: Research Grants