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Reductive openings of benzylidene acetals. Kinetic studies of borane and alane activation by Lewis acids.

Johnsson, Richard LU ; Cukalevski, Risto; Dragén, Fanny LU ; Ivanisevic, Damir; Johansson, Ida; Petersson, Linn LU ; Elgstrand Wettergren, Erika; Yam, Ka Bo; Yang, Beatrice and Ellervik, Ulf LU (2008) In Carbohydrate Research 343. p.2997-3000
Abstract
The reaction kinetics for a number of reductive openings of methyl 2,3-di-O-benzyl-4,6-O-benzylidene-alpha-d-glucopyranoside have been investigated. Openings to give free HO-6 (using BH(3).THF-AlCl(3)-THF or LiAlH(4)-AlCl(3)-Et(2)O) follow first order kinetics, while reactions yielding free HO-4 (using BH(3).NMe(3)-AlCl(3)-THF or BH(3).NMe(3)-BF(3).OEt(2)-THF) follow higher order kinetics. The addition of water to the BH(3).NMe(3)-AlCl(3)-THF results in faster reactions. The BH(3).SMe(2)-AlCl(3)-THF system constitutes a borderline case, yielding both free HO-6 (by a first order reaction) and free HO-4 (by a higher order reaction). These results correlate well with the concept of regioselectivity by activation of borane complexes.
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Carbohydrate Research
volume
343
pages
2997 - 3000
publisher
Elsevier
external identifiers
  • pmid:18789434
  • wos:000261134300020
  • scopus:53849132333
ISSN
1873-426X
DOI
10.1016/j.carres.2008.08.022
language
English
LU publication?
yes
id
89ae571f-9202-43fe-a96d-b8e323cd73e9 (old id 1243039)
date added to LUP
2008-10-10 09:04:01
date last changed
2017-01-01 04:31:35
@article{89ae571f-9202-43fe-a96d-b8e323cd73e9,
  abstract     = {The reaction kinetics for a number of reductive openings of methyl 2,3-di-O-benzyl-4,6-O-benzylidene-alpha-d-glucopyranoside have been investigated. Openings to give free HO-6 (using BH(3).THF-AlCl(3)-THF or LiAlH(4)-AlCl(3)-Et(2)O) follow first order kinetics, while reactions yielding free HO-4 (using BH(3).NMe(3)-AlCl(3)-THF or BH(3).NMe(3)-BF(3).OEt(2)-THF) follow higher order kinetics. The addition of water to the BH(3).NMe(3)-AlCl(3)-THF results in faster reactions. The BH(3).SMe(2)-AlCl(3)-THF system constitutes a borderline case, yielding both free HO-6 (by a first order reaction) and free HO-4 (by a higher order reaction). These results correlate well with the concept of regioselectivity by activation of borane complexes.},
  author       = {Johnsson, Richard and Cukalevski, Risto and Dragén, Fanny and Ivanisevic, Damir and Johansson, Ida and Petersson, Linn and Elgstrand Wettergren, Erika and Yam, Ka Bo and Yang, Beatrice and Ellervik, Ulf},
  issn         = {1873-426X},
  language     = {eng},
  pages        = {2997--3000},
  publisher    = {Elsevier},
  series       = {Carbohydrate Research},
  title        = {Reductive openings of benzylidene acetals. Kinetic studies of borane and alane activation by Lewis acids.},
  url          = {http://dx.doi.org/10.1016/j.carres.2008.08.022},
  volume       = {343},
  year         = {2008},
}