From conventional to greener catalytic approaches for carbohydrates etherification - Carbohydrate Chemistry: Chemical and Biological Approaches - page 94

progresses in the selectivity of this reaction using suitable protecting
groups. Metal and acid catalyzed reactions are cleaner in the sense that
they avoid salts formation and thus purification steps. Most of the
catalyzed transformations have been developed with polyols such as
glycerol that are relatively tolerant to drastic reaction conditions (tem-
perature, acidity). Mild conditions are needed for the transformation of
higher polyols and carbohydrates in order to avoid their degradation or
unwanted transformations such as dehydrations. Reactions that fulfil
this requirement remain rare thus limiting the variety of organic group
that can be grafted. Largely described in this account, the side products
free telomerization reaction has allowed to synthesize C8 ethers under
catalytic and mild conditions. However, large progresses need to be ob-
tained, in particular toward improved selectivities (regio, mono...)in
order to synthesize new compounds with well defined and unique
structures for targeted applications. In that context, one may find solu-
tions coming from chemical engineering, where controlling the select-
ivity at limited conversions and recycling the substrate(s) under
continuous flow under biphasic conditions have been proposed, a tech-
nical process which may lead to industrial applications. 94

Acknowledgements
This chapter is dedicated to the memory of Andr´ Lubineau, whom which
we collaborated within the frame of the Groupement Scientifique CNRS/
B´ghin-Say Sucrochimie during the early 90ies. As such, he was aware of
our work on palladium catalyzed telomerization of butadiene with su-
crose in water using TPPTS. We do remember his strong motivation for
the use of water as solvent for organic reactions. When we spoke with or
about him, we often used the following catch phrase: ''Andr ´ Lubineau,
ou la chimie dans l'eau''. We are confident that he was proud of what he
considered as a compliment. Many thanks Andr ´ for your contribution in
this field.

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