RT info:eu-repo/semantics/article
T1 Sodium Mediated Deprotonative Borylation of Arenes Using Sterically Demanding B(CH2SiMe3)3: Unlocking Polybasic Behaviour and Competing Lateral Borane Sodiation
A1 Tortajada Navarro, Andreu
A1 Bole, Leonie J
A1 Mu, Manting
A1 Stanford, Martin
A1 Peñas de Frutos, Marconi Nicolás
A1 García Melchor, Max
A1 Hevia, Eva
K1 Borane Sodiation
K1 23 Química
AB 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
PB Royal Society of Chemistry
SN 2041-6520
YR 2023
FD 2023
LK https://uvadoc.uva.es/handle/10324/59578
UL https://uvadoc.uva.es/handle/10324/59578
LA eng
NO Chemical Science, 2023
NO Producción Científica
DS UVaDOC
RD 25-dic-2024