File(s) under permanent embargo
Thermal dehydroboration: experimental and theoretical studies of olefin elimination from trialkylboranes and its relationship to alkylborane isomerization and transalkylation
journal contribution
posted on 2023-05-18, 05:50 authored by Weliange, NM, McGuinness, DS, Patel, JThe thermal elimination of α-olefin from tri-n-alkylborane (dehydroboration) has been studied both experimentally and theoretically. High-temperature 1H NMR spectroscopy and temperature quench experiments revealed no evidence for practically significant concentrations of free olefin at temperatures up to 200 °C. Furthermore, attempts to remove 1-octene from tri-n-octylborane by prolonged heating under vacuum were largely unsuccessful. The experimental findings were supported by high-level theoretical calculations, which predicted a very minor equilibrium concentration of dehydroboration products at temperatures less than 200 °C. The results revealed that a putative continuous dehydroboration process will most likely be a slow process and will be difficult to achieve selectively. At the same time, reversible dehydroboration was found to be the most likely route for alkylborane isomerization and transalkylation reactions, and theoretical findings were used to rationalize previous experimental findings. A range of alternative mechanistic proposals for isomerization and transalkylation were also evaluated and were found to be uncompetitive with dehydroboration.
Funding
Australian Research Council
History
Publication title
OrganometallicsVolume
33Issue
16Pagination
4251-4259ISSN
0276-7333Department/School
School of Natural SciencesPublisher
Amer Chemical SocPlace of publication
1155 16Th St, Nw, Washington, USA, Dc, 20036Rights statement
Copyright 2014 American Chemical SocietyRepository Status
- Restricted