Selective Boryl‐Anion Migration in a Vinyl sp2−sp3 Diborane Induced by Soft Borane Lewis Acids |
| |
Authors: | Valerio Fasano Dr Jessica Cid Richard J Procter Emily Ross Prof?Dr Michael J Ingleson |
| |
Institution: | School of Chemistry, University of Manchester, Manchester, UK |
| |
Abstract: | An intramolecular 1,2‐boryl‐anion migration from boron to carbon has been achieved by selective activation of the π system in (vinyl)B2Pin2)]? using “soft” BR3 electrophiles (BR3=BPh3 or 9‐aryl‐BBN). The soft character is key to ensure 1,2‐migration proceeds instead of oxygen coordination/B?O activation. The BR3‐induced 1,2‐boryl‐anion migration represents a triple borylation of a vinyl Grignard reagent using only B2Pin2 and BR3 and forms differentially protected 1,1,2‐triborylated alkanes. Notably, by increasing the steric bulk at the β position of the vinyl Grignard reagent used to activate B2Pin2, 1,2‐boryl‐anion migration can be suppressed in favor of intermolecular {BPin}? transfer to BPh3, thus enabling simple access to unsymmetrical sp2?sp3 diboranes. |
| |
Keywords: | boranes borylation Grignard reagents Lewis acids 1 2-migration |
|
|