Balancing Leaving Group Ability and the ß-Effect: Exploring the Synthetic Utility of Chlorosilyl Groups

Chlorosilanes have generally been ignored in the area of organic synthesis. It is demonstrated that these materials have a diminished but significant ß-effect when compared to trialkylsilyl species and, as importantly, a lower leaving group ability. The utility of chlorosilyl groups in addition reactions to styrylsilanes is described. 1. Introduction 2. Silicon as a Leaving Group: Mechanistic Implications 3. Determining the Relative ß-Effect 4. Addition Reactions to Styrylsilanes 4.1. Acylation 4.2. Addition of Alkyl Cations 4.3. Protonation 5. Other Intramolecular Additions 6. Controlled Cyclization 7. Conclusion