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Table 3 Concurrent cascade composed of L–S coupling and enantio-
divergent ADHs for the synthesis of chiral alcohols
the DFG (grant no. Bo1862/6-1) is gratefully acknowledged.
The authors thank Prof. Dr Werner Hummel, Bielefeld Uni-
versity, for the generous donation of the expression system for
the ADH from Lactobacillus kefir.
ADH-a
LK-ADH
#
R
Yield [%]
ee [%]
Yield [%]
ee [%]
4a
4b
4c
4d
4e
4f
Ph
65
60
47
99
75
61
99 (S)
99 (S)
99 (S)
99 (S)
99 (S)
99 (S)
81
57
53
50
64
53
99 (R)
99 (R)
99 (R)
99 (R)
99 (R)
99 (R)
4-Cl-Ph
3-Cl-Ph
4-Br-Ph
4-F-Ph
4-CF3-Ph
Conflicts of interest
There are no conflicts to declare.
Notes and references
ADH-a from Rhodococcus ruber; LK-ADH from Lactobacillus kefir. Reac-
tion conditions: 100 mM concentration of 1b, boronic acid (1.7 equiv.),
CuTC (1.6 equiv.), Pd2(dba)3 (2.5 mol%), P(OEt)3 (20 mol%), ADHs in
Tris–HCl buffer (320 mM, pH 8.0) and i-PrOH (30% (v/v) referring to the
biocatalytic reaction chamber) as cosubstrate, 24 h reaction time.
¨
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slowly diffused back into the coupling chamber. Under these
optimized conditions, we also tested the o-TA from Codexis but
no conversion to the desired chiral amine 5a was observed.
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deactivating effect by phenyl boronic acid (2a) or the corres-
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