Table 2 Selective acylation of 2 different alcohols (1 : 1 ratio) with
butyric anhydridea
that allows for the reaction of otherwise non-reactive species,
significantly improving the effects observed for surfactant-
based systems. This is the first example of polymeric nanoreactor
capable of effectively distinguishing from a pool of substrates of
similar or different reactivities and where specificity is achieved
based on substrate hydrophobicity. We see these results as an
initial approach towards enzyme mimics for organic reactions
in water.
Catalyst
% Conversion (2a + 2b)
M-DMAP
DMAP
60 (0 + 60)
>99 (>99 + 2)
65 (45 + 20)
The EPSRC and AWE are thanked for financial support.
Ignacio Cotanda is thanked for the cover image. The
SEC equipment used in this research was obtained through
Birmingham Science City with support from Advantage West
Midlands and part funded by the European Regional
Development Fund.
sDMAPb
a
Reaction contained 1 mol% of catalyst, 1 equivalent of each alcohol,
1.5 equivalents of auxiliary base (DIPEA) and 3 equivalents of
anhydride. Conversions determined by GC analysis with mesitylene
as the internal standard. Calculation of % catalyst is described in the
b
ESI. 10 mg of SDS in 2 mL of nanopure water. R = CH2CH2CH3.
Notes and references
z In our case, since the mol% catalyst is 1, the values given for
Table 3 Selective acylation of 4 different alcohols with butyric
anhydridea
percentage of conversion are also the turnover numbers.
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Conversion (%)
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2a
3a
3bb
3c
>99
32
>99
75
Trace
Trace
Trace
>99
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In conclusion, we have shown that polymeric organocatalytic
nanoreactors are not only very efficient supported catalyst for
organic species in aqueous media (with all known advantages of
these systems) but also show specific substrate recognition able
to drastically modify the selectivity of the reactions based on the
simple concept of hydrophobicity. Moreover, the hydrophobic
core-substrate attraction induced by the unique nature of the
polymeric micelle creates a concentrated catalytic environment
c
10282 Chem. Commun., 2012, 48, 10280–10282
This journal is The Royal Society of Chemistry 2012