Chemistry Reference
In-Depth Information
1)
Saccharomyces carlsbergensis
old yellow enzyme, NADP
+
,
glucose-6-phosphate,
glucose-6-phosphate dehydro-
genase, buffer, pH 6.95
R
R
O
2
N
H
2
N
2) H
2
, Raney-Ni
3) HCl,
CO
2
Et
CO
2
H
Δ
158
(
R
)-
159
Selected examples
Me
Et
n
-Pr
O
2
N
O
2
N
O
2
N
Me
CO
2
Et
CO
2
Et
CO
2
Et
(
R
)-
159b
>98% conversion
94% ee
(
R
)-
159c
>98% conversion
96% ee
(
R
)-
159a
>98% conversion
91% ee
Scheme 6.69.
12-Oxophytodienoate red uctase
from
Lycopersicon esculentum
formate dehydrogenase,
formate, NAD
+
O
O
Me
Me
NPh
NPh
O
O
160
(
R
)-
161
99% conversion
97% ee
Scheme 6.70.
In spite of high suitability of these enoate reductases, there is an increasing demand
for further enzymes capable of reducing C=C double bonds, thus expanding the diversity
of biocatalysts for this important reaction. Recently, various microbial enzymes have
been studied with respect to their application in organic synthesis, and recombinant
forms thereof are now available [270,271]. A further elegant step in this direction has
been recently reported by Faber et al., demonstrating the suitability of an 12-oxophyto-
dienoate reductase from
Lycopersicon esculentum
(tomato) as an air-stable enoate
reductase in organic syntheses [271,272]. This example also shows that enzymes of plant
origin can be used as effi cient biocatalysts in organic synthesis. A broad range of acti-
vated alkenes have been successfully reduced, leading to high enantioselectivities in
most cases. For example, reduction of an α - substituted maleimide
160
proceeds under
the formation of the desired product (
R
) -
161
with excellent 99% conversion and 97%
ee when using an FDH for cofactor regeneration (Scheme 6.70).
