Chemistry Reference
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Scheme 11 Reduction of the carbonyl group of cyclohexen-2-one and isophorone (1,2
products) by sodium borohydride and possible concomitant reduction of the double bond
(1,4 products).
Table 8 Effect of sugar additives on the reduction of
double bond in the cyclohenenone and isophorone by
sodium borohydride.
Enone
Additives
1,2 : 1,4
28
-
1 : 1
28
methyl a-glucoside 2.5 M
1 : 1
28
a-cyclodextrin
1.9 : 1
28
b-cyclodextrin
1 : 2.1
28
sucrose 2.5 M
2.4 : 1
29
-
5.7 : 1
29
sucrose 2.5 M
6.7 : 1
29
methyl a-glucoside 2.5 M
11.5 : 1
Consistent results were observed in the case of a wider series of a,b-
unsaturated ketones in presence of sugar and sugar derivatives chosen
for their amphiphilic character (Table 8).
31,38,40
In all cases, the reaction
was more directed towards more monoreduction, therefore improving
the method targeting allylic alcohols, useful reactive systems for further
chemical elaboration.
25
Though these sugar-solutions are chiral media,
there was no significant asymmetric induction in these reactions.
4 Polarity as a targeted property in functional biobased
molecules
Using carbohydrates as starting materials towards chemicals is nowadays
a vast field of research. One strategy is to break down biomass by catalytic
transformations to small reactive fragments such as CO or H
2
(syngas)
which are then recombined in more elaborated hydrocarbons, thus
allowing to substitute old processes based on fossil resources to new
biobased processes, though ending with identical final compounds.
41,42
Another strategy is to transform sugars into more elaborated synthons,
referred to as biobased platform molecules,
43
typical examples being the
chemistry related to succinic acid,
44
HMF
45
or furfural.
46
Going further in
the complexity of the sugar derivation, another way is to create new
molecules in which a significant part of the starting sugar skeleton
structure remains in the target. A typical example is the Lubineau re-
action towards C-glycosylation which has been further applied to in-
novative compounds for the cosmetic industry,
47,48
detailed in another
chapter of this topic by M. Philippe and colleagues.
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