| Title: |
Sodium Mediated Deprotonative Borylation of Arenes Using Sterically Demanding B(CH2SiMe3)3: Unlocking Polybasic Behaviour and Competing Lateral Borane Sodiation |
| Authors: |
Tortajada Navarro, Andreu; Bole, Leonie J; Mu, Manting; Stanford, Martin; Peñas de Frutos, Marconi Nicolás; García Melchor, Max; Hevia, Eva |
| Publisher Information: |
Royal Society of Chemistry |
| Publication Year: |
2023 |
| Collection: |
UVaDOC - Repositorio Documental de la Universidad de Valladolid |
| Subject Terms: |
Borane Sodiation; 23 Química |
| Description: |
Producción Científica ; The deprotonative metalation of organic molecules has become a convenient route to prepare functionalised aromatic substrates. Amongst the different metallating reagents available, sodium bases have recently emerged as a more sustainable and powerful alternative to their lithium analogues. Here we report the study of the sterically demanding electrophilic trap B(CH2SiMe3)3 for the deprotonative borylation of arenes using NaTMP (TMP = 2,2,6,6-tetramethylpiperidide) in combination with tridentate Lewis donor PMDETA (PMDETA = N,N,N′,N′′,N′′-pentamethyldiethylenetriamine). Using anisole and benzene as model substrates, unexpected polybasic behaviour has been uncovered, which enables the formal borylation of two equivalents of the relevant arene. The combination of X-ray crystallographic and NMR monitoring studies with DFT calculations has revealed that while the first B–C bond forming process takes place via a sodiation/borylation sequence to furnish [(PMDETA)NaB(Ar)(CH2SiMe3)3] (I) species, the second borylation step is facilitated by the formation of a borata-alkene intermediate, without the need of an external base. For non-activated benzene, it has aslo been found that under stoichimetric conditions the lateral sodiation of B(CH2SiMe3)3 becomes a competitive reaction pathway furnishing a novel borata-alkene complex. Showing a clear alkali-metal effect, the use of the sodium base is key to access this reactivity, while the metalation/borylation of the amine donor PMDETA is observed instead when LiTMP is used ; Universidad de Valladolid. Margarita Salas Postdoctoral Fellowship (CONVREC-2021-221) ; University of Bern and the Swiss National Science Foundation (Grant numbers 188573, 210608 and R'Equip 206021_177033) ; The Irish Research Council (M.M. GOIPG/2021/88) |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
English |
| Relation: |
https://pubs.rsc.org/en/content/articlelanding/2023/sc/d3sc01705b; https://doi.org/10.1039/D3SC01705B; Chemical Science, 2023; https://uvadoc.uva.es/handle/10324/59578; Chemical Science |
| DOI: |
10.1039/D3SC01705B |
| Availability: |
https://uvadoc.uva.es/handle/10324/59578; https://doi.org/10.1039/D3SC01705B |
| Rights: |
Atribución 4.0 Internacional ; info:eu-repo/semantics/openAccess ; http://creativecommons.org/licenses/by/4.0/ ; © 2023 The Authors |
| Accession Number: |
edsbas.7C0A92AA |
| Database: |
BASE |