Trichosporon cutaneum-promoted deracemization of (±)-2-hydroxindan-1-one: a mechanistic study

Article abstract of DOI:10.1016/j.tetasy.2007.08.007

A mechanistic study of the deracemization of (±)-2-hydroxy-1-indanone mediated by the yeast Trichosporon cutaneum to afford pure (1S,2R)-1,2-indandiol is reported. The key aspect of the study was the use of pure (R)- and (S)-2-hydroxy-1-indanone enantiomers to ensure reliable conclusions. Experiments in the absence of yeast cells or using dead cells disclosed that the pure enantiomers were not racemized, which suggest that the whole dynamic kinetic resolution process is enzymatic in character. When living yeast cells were used the (R)-substrate was smoothly converted to (1S,2R)-1,2-indandiol, whilst the (S)-2-hydroxy-1-indanone was converted to the same diol through a more complex fashion, which requires a more lengthy oxidation-reduction pathway having the 1,2-indanedione as an achiral intermediate. An unexpected observation was that 1,2-indanone acts as a moderate inhibitor of the reductive enzymes acting in the conversion of (R)-2-hydroxy-1-indanone to (1S,2R)-1,2-indandiol.

Full text of DOI:10.1016/j.tetasy.2007.08.007

Tetrahedron: Asymmetry 18 (2007± 2030–2036
Trichosporon cutaneum-promoted deracemization of
(
± ±-ꢀ-ꢁhdroꢂindan-ꢃ-oneꢄ a mecꢁanistic studh
a
a
b
a
Tarcila Cazetta, In eˆ s Lunardi, Gelson J. A. Concei c¸ a˜ o, Paulo J. S. Moran
a,
*
and J. Augusto R. Rodrigues
a
State University of Campinas, Institute of Chemistry, CP 6154, 13084-971 Campinas-SP, Brazil
Department of Basic Sciences, College of Animal Science and Food Engineering, University of S a˜ o Paulo,
CP 23, 13635-900 Pirassununga-SP, Brazil
b
Received 6 March 2007; revised 19 June 2007; accepted 2 August 2007
Abstract—A mechanistic study of the deracemization of (± ±)2)hydroꢀy)1)indanone mediated by the yeast Trichosporon cutaneum to
afford pure (1S,2R±)1,2)indandiol is reported. The key aspect of the study was the use of pure (R±) and (S±)2)hydroꢀy)1)indanone
enantiomers to ensure reliable conclusions. Eꢀperiments in the absence of yeast cells or using dead cells disclosed that the pure enantio)
mers were not racemized, which suggest that the whole dynamic kinetic resolution process is enzymatic in character. When living yeast
cells were used the (R±)substrate was smoothly converted to (1S,2R±)1,2)indandiol, whilst the (S±)2)hydroꢀy)1)indanone was converted to
the same diol through a more compleꢀ fashion, which requires a more lengthy oꢀidation–reduction pathway having the 1,2)indanedione
as an achiral intermediate. An uneꢀpected observation was that 1,2)indanone acts as a moderate inhibitor of the reductive enzymes acting
in the conversion of (R±)2)hydroꢀy)1)indanone to (1S,2R±)1,2)indandiol.
ꢀ
2007 Elsevier Ltd. All rights reserved.
ꢃ. Introduction
Nowadays, a versatile environmentally friendly alternative
to prepare enantiopure compounds involves biocatalytic
resolution of racemates by microbial enzymes. The derace)
mization with kinetic resolution method often provides
compounds with high enantiomeric eꢀcess although the
maꢀimum theoretical yield of product or substrate is only
Enantiomerically pure 1,2)diols are an important com)
monly occurring functional group pattern in natural pro)
ducts such as carbohydrates and polyketides in chiral
ligands used in asymmetric catalysis, and the literature
1
9
details a number of methods for their synthesis. Therefore,
50% in such a process. This limitation of kinetic resolution
much effort has been invested in the development of stereo)
selective methods for 1,2)diol synthesis. A very powerful
one for preparing syn)1,2)diols is the Sharpless asymmetric
can be overcome by employing a deracemization technique
known as dynamic kinetic resolution (DKR±. DKR has
recently become not only an alternative to traditional
kinetic resolution, but also a new procedure for asymmetric
2
dihydroꢀylation of trans)disubstituted olefins.
1
0
synthesis. It is one of the most useful and reliable meth)
ods to prepare a single chiral compound bearing two or
more stereocenters starting from a racemate, with a theo)
retical yield of 100%. Several eꢀamples were reported
Optically active amino alcohols are also important struc)
tural building blocks found in a plethora of natural pro)
3
ducts. Their stereoselective synthesis has been a subject
4
11
of recent interest. In addition, 1,2)amino alcohol residues
employing this dynamic kinetic resolution (DKR±.
are also present in many important commercial drugs as
5
6
7
chloramphenicol, ephedrine, and indinavir, and can be
Recently, we reported a biocatalytic synthesis of (1S,2R±)
1,2)indandiol ꢀ from 1,2)indanone with high stereoselectiv)
ity, using resting whole cells of the yeast Trichosporon
cutaneum. Monitoring of the reaction profile by chiral
GC analysis disclosed that the biocatalytic reduction of
the 1,2)indandione was not a simple one)step stereo)
selective reduction. In fact, it was observed that the
8
prepared from a 1,2)diol through a Ritter reaction.
1
2
*
0
Corresponding author. Tel.: +55 1935213141; faꢀ: +55 1935213023;
e)mail: jaugusto@iqm.unicamp.br
957)4166/$ ) see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetasy.2007.08.007

T. Cazetta et al. / Tetrahedron: Asymmetry 18 (2007) 2030–2036
2031
O
O
OH
Trichosporon
cutaneum
Trichosporon
cutaneum
O
OH
OH
1
benzoin 3
(1S,2R)-2
Scꢁeme ꢃ.
(
(
± ±)2)hydroꢀy)1)indanone was being formed as a racemate
Scheme 1±. Therefore, the results indicate that the reac)
were conducted in parallel reactions for each enantiomer
using the following conditions: (a± in the absence of T.
cutaneum cells, each substrate, (R±)3 or (S±)3, was indepen)
dently suspended in distilled water; (b± each substrate, (R±)
3 or (S±)3, was treated with dead T. cutaneum cells (yeast
cells were killed by treatment with ethanol and acetone±;
(c± each substrate, (R±)3 or (S±)3, was treated with dead
T. cutaneum cells (cells were heated in an autoclave at
121 ꢁC for 30 min±. All three eꢀperiments were performed
on an orbital shaker (170 rpm± at 28 ꢁC for a week.
tive enantiomer is being depleted by the stereoselective
reduction to give ꢀ and the equilibrium (R±)3/(S±)3 concen)
trations are constantly re)adjusted until the complete con)
version of the substrate occurred. In the mechanism
proposed, the unreactive enantiomer (S±)3 is isomerized
to (R±)3, in a concomitant step. As a result, the clean
dynamic kinetic resolution (DKR± of the racemic 2)hydr)
oꢀy)1)indanone ꢃ afforded enantiomerically pure (1S,2R±)
1
,2)indandiol (ꢀ± in high yield (90%± and with an eꢀcellent
ee (>99%±.
The miꢀtures were then eꢀtracted with ethyl acetate and
after concentration the resulting residues were promptly
analyzed by chiral GC. In all cases, the analysis shows no
isomerization of the pure substrates (R±)3 or (S±)3, which
indicates that the dynamic kinetic resolution observed in
the biotransformation of dione ꢃ by T. cutaneum is enzy)
matic as a whole. Since a stereoinversion of (S±)3 to (R±)
3 is required to eꢀplain the formation of (1S,2R±)ꢀ as the
major product (90% yield±, the eꢀpression by T. cutaneum
of a racemase that would act on the isomerization of enan)
tiomer (S±)3 was initially postulated. To investigate this
hypothesis, we planned and performed new eꢀperiments
to evaluate the details of the biotransformation of pure
enantiomers (R±) or (S±)3 separately. Accordingly, the
eꢀperiments were carried out in distilled water using resting
cells of T. cutaneum and pure (R±) or (S±)3 as substrates.
ꢀ
. Results and discussion
In order to better understand the microbial deracemization
of the title compound, it was imperative to undertake a sys)
tematic study of the bio)reduction reaction, using pure
enantiomers of 2)hydroꢀy)1)indanone as substrates. The
(
R±) and (S±)2)hydroꢀy)1)indanone (3± were readily avail)
1
2
able from (R±) and (S±)phenylalanine in 35% (98% ee±
and 32% (97% ee± isolated yield, through the method pre)
viously described by Kajiro et al.13 (Scheme 2±. Attempts
to use a different less eꢀpensive catalyst for the last step
in the synthesis (acetate 6 hydrolysis± were fruitless.
The first step to understand the biotransformation of (± ±)3
by T. cutaneum was to find the origin of the stereoinversion
of the starting material observed in the proposed dynamic
kinetic resolution (DKR± process. Thus, to establish
whether the conversion of (S±) to the (R±)3 enantiomer
was induced by some component of the reaction media
or mediated by an enzyme present in yeast, we carried
out some simple control eꢀperiments. These eꢀperiments
The biotransformations were conducted on an orbital sha)
ker (170 rpm± at 28 ꢁC until complete conversion of the
substrate. Reactions were periodically monitored through
sample analysis by chiral GC. We observed that the (R±)3
was biotransformed by T. cutaneum in 22 h in a clean fash)
ion (no by products such as indanone ꢃ were detected± giv)
ing ultimately (1S,2R±)diol ꢀ as the sole product in both
O
NH2
a
OH
b, c, d
OAc
COOH
COOH
4
5
6
e
O
OH
(
R)-3
ꢀ
1
Scꢁeme ꢀ. Reagents and conditions: (a± NaNO
2
, 1 mol L
H
2
SO
4
, 0 ꢁC to rt; (b± Ac
2
O/pyridine, 0 ꢁC to rt, 12 h; (c± SOCl
2
3
, rt to 50 ꢁC, 3 h; (d± AlCl /
CH Cl , rt, 3 h; (e± Sc(OTf± (20 mol %± MeOH–H
2
2
3
2
O, rt, 61 h.

2032
T. Cazetta et al. / Tetrahedron: Asymmetry 18 (2007) 2030–2036
On the other hand, the biotransformation of (S±)3 to
1S,2R±)ꢀ took place through a different route than that
100
(
observed for (R±)3 enantiomer. Detailed analysis of the
results of the eꢀperiments show that substrate (S±)3 was
isomerized to form enantiomer (R±)3 through the interme)
diate formation of dione ꢃ by oꢀidation followed by further
reduction of the dione by T. cutaneum to afford (1S,2R±)
8
0
0
0
0
6
4
2
(
R
)-3
)-3
,2
(
S
1
2
diol ꢀ as previously reported by us. Therefore, the
biotransformation of (S±)3 requires the eꢀistence of an
(1S R)-2
trans-indanediol
equilibrium)controlled
reduction–oꢀidation
sequence
rather than the action of a single enzyme (like a racemase±.
Faber and co)workers also observed a similar reduction–
oꢀidation sequence when studying the racemization of
0
(
R±)2)hydroꢀy)1)indanone 3 by Lactobacillus paracasei
1
4
DSM 20207. In addition, they found that alkaline med)
ium (pH lower than 10± favored the oꢀidation of the
substrate.
0
5
10
15
20
25
Time (h)
Figure ꢃ. Relative percentage of substrate and products as a function of
time for the reduction of (R±)3 by yeast Trichosporon cutaneum in water at
The complete conversion of (S±)3 by T. cutaneum was
accomplished only after 42 h and in spite of the longer
reaction time, the product (1S,2R±)diol ꢀ was also isolated
in both high yield and ee (85% and 99%, respectively±.
28 ꢁC.
O
OH
2
2 hours
0% yield
9% ee
100
80
OH
OH
9
9
(
R)-3
(1S,2R)-2
6
0
0
Scꢁeme 3.
(
S
)-3
)-3
(R
4
1,2-indanedione 1
,2 )-2
(1S R
high yield and enantiomeric eꢀcess (90% and 99%, respec)
tively± as shown in Figure 1 and Scheme 3. It is important
to stress that (R±)3 was not isomerized to (S±)3 by the yeast
under such eꢀperimental conditions.
trans-indanediol 7
20
0
0
10
20
30
40
50
After complete conversion of the substrate, the cells were
removed by centrifugation and crude product ꢀ was iso)
lated from the aqueous layer by eꢀtraction with ethyl ace)
tate. Purification was achieved by flash chromatography to
give (1S,2R±)ꢀ in 90% yield and 99% ee (Scheme 3±.
Time (h)
Figure ꢀ. Relative percentage of substrate and products as a function of
time for the reduction of (S±)3 by yeast Trichosporon cutaneum in distilled
water at 28 ꢁC.
O
O
O
oxidation
OH
reduction
O
OH
reduction
(
S)-3
intermediate
dione 1
(R)-3
reduction
OH
OH
(
1S,2R)-2
Scꢁeme 4. Proposed general mechanism for the biotransformation of (S±)3 by resting cells of Trichosporon cutaneum in distilled water at 28 ꢁC.

T. Cazetta et al. / Tetrahedron: Asymmetry 18 (2007) 2030–2036
2033
Figure 2 summarizes the compleꢀ biotransformation pro)
file of (S±)3 by T. cutaneum and Scheme 4 depicts a pro)
posed general mechanism for the biotransformation.
20 mg of dione ꢃ was added to the medium. The larger
amounts of dione ꢃ imparted a moderate to intense delay
of the reduction of the substrate and in consequence, the
time required to complete the conversion increased almost
threefold and fivefold (entries 5 and 6, respectively± com)
pared to entry 2. It is clear that the delay observed to com)
plete the conversion of the substrate due to increasing
amounts of dione ꢃ in the medium cannot be simply asso)
ciated with the larger concentration of (R±)3 coming from
the reduction of dione ꢃ since a larger starting amount of
substrate (entry 2± did not change the time required for full
conversion of 50 mg of (R±)3 (entry 1±. Therefore, it is rea)
sonable to propose that in fact dione ꢃ acts as an inhibitor
of the reductase involved in the biotransformation of (R±)3.
In order to better understand the oꢀidation–reduction
equilibrium proposed above, we re)investigated the bio)
reduction of dione ꢃ (50 mg scale± by resting cells of T. cuta-
neum. The eꢀperiments were carried out at 28 ꢁC in distilled
water and incubated in an orbital shaker (170 rpm±. Peri)
odical analyses of samples were performed by chiral GC.
The reaction profile of the biotransformation is shown in
Figure 3. Accordingly, after 10 min of reaction, dione ꢃ
has already been eꢀtensively reduced to (R±)3. However,
it is worth mentioning that traces of dione ꢃ are detected
through)out the reaction, which reinforces the eꢀistence
of an oꢀidation–reduction equilibrium between dione ꢃ
and (S±)3, as proposed in Scheme 4. In spite of the presence
of (R±)3 in the medium in relatively high amounts, the for)
mation of (1S,2R±)diol ꢀ was curiously observed only after
Table ꢃ. Evaluation of the inhibitory profile of 1,2)indandione (ꢃ± on the
biotransformation of substrate (R±)3 by resting cells of T. cutaneum
Entry
Amount of
Amount of ꢃ
Time to full
5
0 h of incubation. In addition, as already observed by us,
the biotransformation of dione ꢃ was sluggish and took
20 h to completion.
(R±)3 (mg±
added (mg±
conversion (h±
1
2
3
4
5
6
50
80
50
50
50
50
0
0
5
10
20
30
22
22
22
22
60
1
1
1
10
00
120
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
We propose the hypothesis that the dione imparts an inhib)
itory effect by competing with compound 3 for the active
site of the enzyme since the compounds are similar in struc)
ture. The inhibitory effect of dione ꢃ on the bio)reduction
of (R±)3 is further evidenced through the analysis of the
chiral GC chromatograms depicted in Figure 4. Accord)
ingly, the final product (1S,2R±)diol ꢀ starts to appear only
after 29 h when dione ꢃ has nearly disappeared from the
medium. We believe that this uneꢀpected behavior is only
reasonably eꢀplained if dione ꢃ truly acts as an inhibitor
of (R±)3 reductase.
(
S
)-3
)-3
(
R
1
(
,2-indanedione 1
,2 )-2
1S
R
-
10
0
20
40
60
80
100
120
Time (h)
Figure 3. Relative percentage of substrate and products as a function of
time during the reduction of ꢃ by yeast Trichosporon cutaneum in water at
3. Conclusion
2
8 ꢁC.
In summary, evidence regarding the mechanism of the
T. cutaneum)mediated deracemization of compound (± ±)3
using pure enantiomers (R±)3 and (S±)3 as substrates has
been provided. The fact that no isomerization occurred in
the absence of living cells of the yeast proved the enzymatic
character of the inversion of the configuration of (S±)3
required to form (1S,2R±)diol ꢀ as the main product. In
addition, it was shown that the biotransformation of
(S±)3 formed 1,2)indandione ꢃ as an intermediate, which
strongly suggests the eꢀistence of an equilibrium)controlled
reduction–oꢀidation sequence rather than the action of a
single enzyme in the isomerization step the biotransforma)
tion. Finally, it was demonstrated that dione ꢃ acts as an
inhibitor of the (R±)3 reductase. As such, this compound
should be avoided as a substrate if the intention is to obtain
(1S,2R±)diol ꢀ in high yield in shorter time. Therefore, it is
reasonable to conclude that (± ±)2)hydroꢀindan)1)one (3±
should be the starting material of choice for the best
results.
Taking in account the delay for the start of the reduction
R±)3 to form (1S,2R±)diol ꢀ and the time)consuming bio)
(
transformation of dione ꢃ, we considered the possibility
that one of the components of the reaction medium is act)
ing as a reductase inhibitor. In order to check such a pos)
sibility, we carried out some new eꢀperiments with T.
cutaneum using the most reactive enantiomer (R±)3 as a
substrate with concomitant introduction of different
amounts of dione ꢃ as shown in Table 1.
The results obtained shed some light on the process. As can
be seen in Table 1, increasing amounts of dione ꢃ played a
paramount effect on the biotransformation profile of (R±)3
by T. cutaneum. In the absence of dione ꢃ the reaction was
quickly completed in 22 h (entry 1±, even when starting
with a larger amount of the substrate (entry 2±. No effects
on the biotransformation of (R±)3 were observed until

2034
T. Cazetta et al. / Tetrahedron: Asymmetry 18 (2007) 2030–2036
Macherey 212117/91 Hydrodeꢀ)b 3P fused silica capillary
columns (25 m · 250 lm · 0.25 lm± with helium or hydro)
ꢀ
1
gen as carrier gases (1.0 mL min ±. The strain of T. cuta-
neum (CCT 1903± was purchased from the ‘‘Andr e´ Tosello’’
Research Foundation (Brazil±. Culture media were pur)
chased from Biobr a´ s (Brazil±. Flash column chromatogra)
phy was carried out on silica (200–400 mesh, Merck±.
4.ꢀ. (R±-ꢀ-Hhdroꢂh-3-pꢁenhlpropanoic acid 5
Aqueous NaNO (21 g, 300 mmol, in 50 mL of H O± and
2
2
ꢀ1
H SO (3.2 mol L aqueous solution, 50 mL± were added
2
4
to a solution of D)(R±)phenylalanine 4 (10 g, 61 mmol± in
ꢀ
1
H SO (1 mol L , 200 mL± over 30 min at 0 ꢁC. The reac)
2
4
tion miꢀture was stirred for 75 min at 0 ꢁC and then
eꢀtracted with EtOAc (3 · 100 mL±. The organic layer
was washed with brine (2 · 100 mL±, dried over anhydrous
Na SO , and the solvent was removed under reduced pres)
2
4
sure. The residue was purified by recrystallization (EtOAc–
heꢀane 4:1± to give (R±)2)hydroꢀy)3)phenylpropanoic acid
5
(7.7 g, 77% yield, >99% ee± as colorless crystals. Enantio)
meric eꢀcess of (R±)5 was determined after conversion to its
methyl ester: diazomethane was added dropwise (0.5 mL,
ethyl ether solution± to a solution of (R±)5 (10 mg± in
MeOH (5 mL±. The resulting miꢀture was concentrated
under reduced pressure. The residue was dissolved in EtOH
and analyzed by GC–MS using a chiral column.
1
5
20
D
Mp 118.4–121.5 ꢁC (lit. 126.0–127.0 ꢁC±; ½aꢁ ¼ þ25:4 (c
3
20
D
1
.0, H O± (lit. ½aꢁ ¼ þ20:4 (c 1.0, H O±±. Spectroscopic
2
2
data for compound (R±)5 were in agreement with those pre)
viously reported.
Starting with L)(S±)phenylalanine and using the same
methodology (S±)2)hydroꢀy)3)phenylpropanoic acid (S±)5
was obtained in 75% yield, >99% ee. Mp 118.4–121.5 ꢁC
3
3
20
D
(
½
lit. 126.0–127.0 ꢁC±; ½aꢁ ¼ ꢀ27:0 (c 1.0, H O± (lit.
2
2
0
D
aꢁ ¼ ꢀ20:0 (c 1.0, H O±±. Spectroscopic data for com)
2
pound (S±)5 were in agreement with those previously
reported.
4.3. (R±-ꢀ-Acetoꢂh-ꢃ-indanone 6
Figure 4. Chiral GC chromatograms obtained at different times for the
biotransformation of (R±)3 by resting cells of T. cutaneum, in the presence
of 20 mg of dione ꢃ.
Acetic anhydride (5.3 mL, 56 mmol± at 0 ꢁC was added to a
solution of (R±)2)hydroꢀy)3)phenylpropanoic acid (5±
(7.7 g, 46.4 mmol± in pyridine (50 mL±. The resulting
miꢀture was stirred at 25 ꢁC for 12 h before concentration
under reduced pressure. The residue was redissolved
ꢀ
1
4
. Eꢂperimental
in EtOAc (30 mL±, washed with HCl (1 mol L , 2 ·
5
0 mL±, dried over anhydrous Na SO , and the solvent
2
4
4
.ꢃ. General
was removed under reduced pressure to afford (R±)2)acet)
oꢀy)3)phenylpropanoic acid as an amber)colored oil
(9.4 g, 97% yield±. This crude product was used in the neꢀt
step without further purification.
All reagents and solvents were obtained from commercial
1
13
sources. H and C NMR spectra were recorded on Varian
INOVA)500 Gemini 300 spectrometers. Optical rotations
were measured on a Perkin Elmer Polarimeter 341. Melting
points were measured on a Microquimica MQ APF)301
equipment. GC–MS analysis and mass spectra acquisi)
tion were carried out on QP 5000)SHIMADZU or
AGILENT CG 6890/HEWLETT PACKARD 5973
gas chromatographs equipped with a HP)5MS (5%
phenylmethylpolysiloꢀane, 30 m · 250 lm · 0.25 lm± or a
A solution of crude (R±)2)acetoꢀy)3)phenylpropanoic acid
(9.4 g, 45 mmol±, in thionyl chloride (17 mL, 0.15 mol±
was stirred at room temperature for 20 min and then
heated at 50 ꢁC for 3 h. Removal of all volatile materials
under reduced pressure furnished the crude product, (R±)
2)acetoꢀy)3)phenylpropanoyl chloride (9.2 g, 38.25 mmol,
90% yield±, as an amber)colored oil. This crude product

T. Cazetta et al. / Tetrahedron: Asymmetry 18 (2007) 2030–2036
2035
was used in the neꢀt step without further purification.
4.6. Thpical procedure for tꢁe biotransformation of tꢁe
substrates
Thus, AlCl (13 g, 97 mmol±. was added in one portion to
3
a solution of the oil in CH Cl (400 mL± The resulting
2
2
miꢀture was stirred at 25 ꢁC for 80 min and treated with
an ice)water miꢀture (300 mL±. The organic layer was
removed and the aqueous layer was further eꢀtracted with
CH Cl (3 · 100 mL±. The combined organic eꢀtracts were
A solution of 50 mg of the substrate, that is, (± ±)3, (R±)3,
(S±)3 or diketone ꢃ in ethanol (0.5 mL± was added to a slur)
ry of T. cutaneum CCT 1903 (3 g, wet weight± in sterile dis)
tilled water (50 mL±. The resulting suspension was stirred
on an orbital shaker (166 rpm± at 28 ꢁC until the total con)
sumption of the substrate. After centrifugation (5000 rpm±,
the supernatant and cell pellet were thoroughly eꢀtracted
with ethyl acetate. The organic eꢀtracts were combined,
dried over anhydrous Na SO , and the solvent was
removed under reduced pressure. All the substrates tested
presented (1S,2R±)1,2)indanediol ꢀ as the major product.
Purification was achieved by flash column chromatography
on silica gel (heꢀane/EtOAc 1:1± to furnish desired diol
(1S,2R±)ꢀ (90% yield, >99% ee± as white crystals.
2
2
dried over anhydrous Na SO and the solvent was removed
2
4
under reduced pressure. The residue was purified by flash
column chromatography on silica gel (heꢀane/EtOAc 4:1±
to give compound (R±)6 (5 g, 65% yield, >99% ee± as an
2
off)white solid. Mp 81.3–81.5 ꢁC; (lit. 80.5–81.5 ꢁC±. IR
2
4
ꢀ
1 1
(
KBr± 1728, 1607, 1372, 1252, 1223, 1184 cm . H NMR
(
500 MHz, CDCl ± d: 2.19 (s, 3H±, 3.04 (dd, J = 4.7 and
3
1
7.1 Hz, 1H±, 3.66 (dd, J = 8.0 and 17.1 Hz, 1H±, 5.42
(
dd, J = 4.7 and 8.0 Hz, 1H±, 7.39–7.46 (m, 2H±, 7.64 (t,
1
3
J = 7.2 Hz, 1H±, 7.78 (d, J = 7.8 Hz, 1H±; C NMR
(
1
125 MHz, CDCl ± d: 20.8, 33.4, 74.0, 124.3, 126.5, 128.0,
3
20
16
34.3, 135.7, 150.2, 170.2, 200.3; ½aꢁ ¼ ꢀ19:0 (c 1.0,
Mp 94–98 ꢁC (lit. 98 ꢁC±. IR (KBr±: 3529, 3439, 3298,
D
2
20
ꢀ1
MeOH± (lit. ½aꢁ ¼ ꢀ19:0 (c 1.0, MeOH±±.
3153, 2923, 1459, 1337, 1187, 1155, 987, 737, 634 cm
H NMR (500 MHz, DMSO)d ± d: 2.76 (dd, J = 15.6 and
;
D
1
6
The (S±)2)acetoꢀy)1)indanone (S±)6 was prepared from
3.7 Hz, 1H±, 2.92 (dd, J = 15.6 and 5.6 Hz, 1H±, 4.24–
4.27 (m, 1H±, 4.58 (d, J = 4.9 Hz, 1H±, 4.78 (dd, J = 6.7
and 4.9 Hz, 1H±, 4.99 (d, J = 6.7 Hz, 1H±, 7.17–7.20 (m,
(
S±)2)hydroꢀy)3)phenylpropanoic acid (S±)5 using the same
20
methodology (54% yield, >99% ee±. ½aꢁ ¼ þ18:7 (c 1.0,
D
1
3
MeOH±.
3H±, 7.30 (m, 1H±; C NMR (125 MHz, DMSO)d ± d:
6
38.28, 72.90, 75.05, 124.76, 124.83, 126.29, 127.62,
4
.4. (R±-ꢀ-ꢁhdroꢂh-ꢃ-indanone 3
140.57, 143.96.
An aqueous solution of Sc(OTf±3 (2.6 g, 5.3 mmol± in
0 mL of distilled water was added to a solution of
5
Acknowledgments
(
(
6
R±)2)acetoꢀy)1)indanone 6 (5 g, 26 mmol± in MeOH
200 mL±. The resulting miꢀture was stirred at 30 ꢁC for
The authors are indebted to FAPESP and CNPq for the
financial support.
0 h and then concentrated under reduced pressure. The
residue was diluted in distilled water (50 mL± and eꢀtracted
with EtOAc (3 · 50 mL±. The organic layer was dried over
anhydrous Na SO and concentrated under reduced pres)
2
4
References
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1
2
. Jarowicki, K.; Kocienski, P. J. J. Chem. Soc., Perkin Trans. 1
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. (a± Jacobsen, E. N.; Marko, I.; Mungall, W. S.; Schr o¨ der, G.;
(
R±)3 (3.2 g, 82% yield, 98% ee± as a colorless solid.
ꢀ
2
Mp 79.9–81.0 ꢁC; (lit. 82.4–83.7 ꢁC±. IR (KBr± 3418, 1716,
Sharpless, K. B. J. Am. Chem. Soc. ꢃ988, 110, 1968–1970.
ꢀ1
1
1
609, 1585, 1303, 1207, 1091, 912, 753 cm ; H NMR
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(
500 MHz, CDCl ± d: 3.02 (dd, J = 5.1 and 16.4 Hz, 1H±,
3
3
.58 (dd, J = 7.8 and 16.4 Hz, 1H±, 3.74 (s, 1H±, 4.58 (dd,
J = 5.1 and 7.8 Hz, 1H±, 7.37–7.47 (m, 2H±, 7.60–7.66 (m,
1
3
1
H±, 7.75 (d, J = 7.5 Hz, 1H±; C NMR (125 MHz CDCl3±
d: 35.2, 74.2, 124.3, 126.6, 127.8, 133.9, 135.7, 150.8, 206.5;
2
D
0
2
20
½
aꢁ ¼ ꢀ53:0 (c 1.0, MeOH± (lit. ½aꢁD ¼ ꢀ57:0 (c 1.0,
MeOH±±.
6
The (S±)2)Hydroꢀy)1)indanone 3 was prepared from (S±)2)
acetoꢀy)1)indanone (S±)6 using the same procedure
7. Reider, P. Chimia ꢃ997, 51, 306–308.
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20
described above. Data: 80% yield, 97% ee, ½aꢁ ¼ þ54:0
D
(
c 1.0, MeOH±.
9
. Faber, K. Biotransformations in Organic Chemistry, 5th ed.;
Springer)Verlag: Berlin, 2004.
4
.5. Growtꢁ conditions of T. cutaneum CCT ꢃ903
1
0. (a± Huerta, F. F.; Minidis, A. B. E.; B a¨ ckvall, J. E. Chem.
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ouraud deꢀtrose broth, 1 L± at 166 rpm at 30 ꢁC on an
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5
005–5010.
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6
min± prior to use in the reactions.

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1
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1