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Reductive openings of acetals: Explanation of regioselectivity in borane reductions by mechanistic studies

Johnsson, Richard LU ; Olsson, Daniel LU and Ellervik, Ulf LU (2008) In Journal of Organic Chemistry 73(14). p.5226-5232
Abstract
The mechanisms of regioselective reductive openings of acetals were investigated in several model systems by a combination of Hammett plots, kinetic experiments, density functional calculations, and B-11 NMR. The regioselectivity of borane reductions of cyclic acetals can be controlled by the choice of borane. Lewis acid activation of BH3 center dot NMe3 increases the reaction rate and renders the borane the most electrophilic species, which associates to the more electron-rich oxygen of the acetal. In contrary, without activation, the regioselectivity is instead directed by the Lewis acid, as exemplified by the reaction with BH3 center dot THF.
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Organic Chemistry
volume
73
issue
14
pages
5226 - 5232
publisher
The American Chemical Society
external identifiers
  • wos:000257543100003
  • scopus:48249088465
ISSN
1520-6904
DOI
10.1021/jo800396g
language
English
LU publication?
yes
id
805e0e9e-1300-41f9-aaa5-d16140a98d04 (old id 1254661)
date added to LUP
2008-10-29 15:40:02
date last changed
2017-01-01 04:50:11
@article{805e0e9e-1300-41f9-aaa5-d16140a98d04,
  abstract     = {The mechanisms of regioselective reductive openings of acetals were investigated in several model systems by a combination of Hammett plots, kinetic experiments, density functional calculations, and B-11 NMR. The regioselectivity of borane reductions of cyclic acetals can be controlled by the choice of borane. Lewis acid activation of BH3 center dot NMe3 increases the reaction rate and renders the borane the most electrophilic species, which associates to the more electron-rich oxygen of the acetal. In contrary, without activation, the regioselectivity is instead directed by the Lewis acid, as exemplified by the reaction with BH3 center dot THF.},
  author       = {Johnsson, Richard and Olsson, Daniel and Ellervik, Ulf},
  issn         = {1520-6904},
  language     = {eng},
  number       = {14},
  pages        = {5226--5232},
  publisher    = {The American Chemical Society},
  series       = {Journal of Organic Chemistry},
  title        = {Reductive openings of acetals: Explanation of regioselectivity in borane reductions by mechanistic studies},
  url          = {http://dx.doi.org/10.1021/jo800396g},
  volume       = {73},
  year         = {2008},
}