Regioselective reductive openings of 4,6-benzylidene acetals: synthetic and mechanistic aspects.
(2011) In Carbohydrate Research 346. p.1358-1370- Abstract
- The use of benzylidene acetals as protecting groups in carbohydrate chemistry is utterly important. The main advantage of benzylidene acetal is the ability for regioselective openings. 4,6-benzylidene acetal can be opened selectively under reductive conditions to yield either free 4-OH or 6-OH. There are a plethora of methods available for regioselective openings, but only a few of these are widely used. In recent years, the mechanism has been investigated for borane mediated openings and it seems likely that the regioselectivity is determined by borane, rather than Lewis acid. When borane is activated by Lewis acids, borane is the most electrophilic species that consequently coordinates to the most nucleophilic oxygen of the acetals,... (More)
- The use of benzylidene acetals as protecting groups in carbohydrate chemistry is utterly important. The main advantage of benzylidene acetal is the ability for regioselective openings. 4,6-benzylidene acetal can be opened selectively under reductive conditions to yield either free 4-OH or 6-OH. There are a plethora of methods available for regioselective openings, but only a few of these are widely used. In recent years, the mechanism has been investigated for borane mediated openings and it seems likely that the regioselectivity is determined by borane, rather than Lewis acid. When borane is activated by Lewis acids, borane is the most electrophilic species that consequently coordinates to the most nucleophilic oxygen of the acetals, usually O-6. This results in the formation of 6-O-benzyl ethers. If borane is not activated, Lewis acid is the most electrophilic species that thus adds to O-6 and hence generates the 4-O-benzyl ether. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1973326
- author
- Ohlin, Markus LU ; Johnsson, Richard LU and Ellervik, Ulf LU
- organization
- publishing date
- 2011
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Carbohydrate Research
- volume
- 346
- pages
- 1358 - 1370
- publisher
- Elsevier
- external identifiers
-
- wos:000292852100002
- pmid:21531396
- scopus:79959984073
- pmid:21531396
- ISSN
- 1873-426X
- DOI
- 10.1016/j.carres.2011.03.032
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Organic chemistry (S/LTH) (011001240)
- id
- b0a5a1e0-a57c-4a05-97f6-10ee7df33e40 (old id 1973326)
- date added to LUP
- 2016-04-01 10:50:39
- date last changed
- 2024-03-10 09:41:52
@article{b0a5a1e0-a57c-4a05-97f6-10ee7df33e40, abstract = {{The use of benzylidene acetals as protecting groups in carbohydrate chemistry is utterly important. The main advantage of benzylidene acetal is the ability for regioselective openings. 4,6-benzylidene acetal can be opened selectively under reductive conditions to yield either free 4-OH or 6-OH. There are a plethora of methods available for regioselective openings, but only a few of these are widely used. In recent years, the mechanism has been investigated for borane mediated openings and it seems likely that the regioselectivity is determined by borane, rather than Lewis acid. When borane is activated by Lewis acids, borane is the most electrophilic species that consequently coordinates to the most nucleophilic oxygen of the acetals, usually O-6. This results in the formation of 6-O-benzyl ethers. If borane is not activated, Lewis acid is the most electrophilic species that thus adds to O-6 and hence generates the 4-O-benzyl ether.}}, author = {{Ohlin, Markus and Johnsson, Richard and Ellervik, Ulf}}, issn = {{1873-426X}}, language = {{eng}}, pages = {{1358--1370}}, publisher = {{Elsevier}}, series = {{Carbohydrate Research}}, title = {{Regioselective reductive openings of 4,6-benzylidene acetals: synthetic and mechanistic aspects.}}, url = {{http://dx.doi.org/10.1016/j.carres.2011.03.032}}, doi = {{10.1016/j.carres.2011.03.032}}, volume = {{346}}, year = {{2011}}, }