Biocatalytically assisted preparation of antifungal chlorophenylpropanols

Article abstract of DOI:10.1016/S0957-4166(02)00415-9

Fermenting baker's yeast converts 4′-chloropropiophenone 1 and 3′-chloropropiophenone 2 into enantiopure (S)-(-)-1-(4′-chlorophenyl)propan-1-ol (S)-3 and (S)-(+)-1-(3′-chlorophenyl)propan-1-ol (S)-4, respectively. Application of inhibitors and organic solvents as additives enhanced the enantiomeric excesses. Enantiopure compounds (R)-(+)-1-(4′-chlorophenyl)propan-1-ol ((R)-3) and (R)-(+)-1-(3′-chlorophenyl)propan-1-ol (R)-4 were prepared by lipase-mediated esterifications of the racemic alcohols. Maximum inhibition of the growth of the phytopathogenic fungus Botrytis cinerea was shown for the (R)-enantiomers.

Full text of DOI:10.1016/S0957-4166(02)00415-9

TETRAHEDRON:
ASYMMETRY
Pergamon
Tetrahedron: Asymmetry 13 (2002) 1681–1686
Biocatalytically assisted preparation of antifungal
chlorophenylpropanols
Antonio J. Bustillo, Josefina Aleu, Rosario Hern a´ ndez-Gal a´ n and Isidro G. Collado*
Departamento de Qu ´ı mica Org a´ nica, Facultad de Ciencias, Universidad de C a´ diz, Rep u´ blica Saharaui s/n, Apdo. 40,
1510 Puerto Real, C a´ diz, Spain
1
Received 27 June 2002; accepted 22 July 2002
Abstract—Fermenting baker’s yeast converts 4%-chloropropiophenone 1 and 3%-chloropropiophenone 2 into enantiopure (S)-(−)-1-
(
4%-chlorophenyl)propan-1-ol (S)-3 and (S)-(+)-1-(3%-chlorophenyl)propan-1-ol (S)-4, respectively. Application of inhibitors and
organic solvents as additives enhanced the enantiomeric excesses. Enantiopure compounds (R)-(+)-1-(4%-chlorophenyl)propan-1-ol
(
(R)-3) and (R)-(+)-1-(3%-chlorophenyl)propan-1-ol (R)-4 were prepared by lipase-mediated esterifications of the racemic alcohols.
Maximum inhibition of the growth of the phytopathogenic fungus Botrytis cinerea was shown for the (R)-enantiomers. © 2002
Elsevier Science Ltd. All rights reserved.
1
. Introduction
ration to be the prevalent enantiopreference. In contrast,
our preparation of (R)-enantiomers was based on
4
Botrytis cinerea is a grey mould that causes damage to
economically important crops such as lettuce, carrots,
tobacco, strawberries and grapes. In southern Spain,
Kazlauskas’ empirical rule for the resolution of sec-
ondary alcohols in the enzymatic O-acetylation process
1
by lipases.
this fungus principally affects strawberries and grapes,
causing significant losses in the Sherry area, where B.
cinerea is considered endemic.
We report herein on the biocatalytic preparation of 3%-
and 4%-chlorophenylpropanols in both absolute configu-
rations, as well as their antifungal properties against B.
cinerea.
In order to find substrates with antifungal properties
against this fungus, we have undertaken a screening of
2
compounds analogous to various phytoalexins. As a
result of these studies, we have found several different
racemic secondary alcohols with skeletons similar to
those of active compounds which exhibit fungicidal
activity against B. cinerea, most notably (±)-1-(4%-
2. Results and discussion
2
.1. Baker’s yeast reduction
In light of the known ability of fermenting baker’s yeast
to reductively transform a variety of ketones into opti-
cally active alcohols with (S)-configuration (Prelog spe-
chlorophenyl)propan-1-ol
phenyl)propan-1-ol 4.
3
and (±)-1-(3%-chloro-
3
cificity family), we decided to undertake a baker’s
Since the absolute configuration of biologically active
compounds is an important factor governing their activ-
ity, we were interested in devising a biocatalytic
approach to the enantiomers of 3 and 4 in order to
compare their antifungal activities. To produce the
desired (S)-enantiomers, we undertook a reduction of
yeast-mediated approach to enantiopure (S)-(−)-1-(4%-
and 3%-chlorophenyl)propanols, (S)-3 and (S)-4, using
the corresponding ketones 4%-chloropropiophenone 1
and 3%-chloropropiophenone 2 as substrates. The results
are shown in Table 1.
3
the ketones using baker’s yeast since the known exam-
A major limitation of this methodology is the difficulty
in extracting the product from the fermentation broth;
consequently, often only moderate yields of products are
obtained, presumably due to absorption of the starting
material and/or product within the larger quantity of
ples of this type of reduction have shown the (S)-configu-
*
0
Corresponding author. Tel.: 34-956-016365; fax: 34-956-016288;
e-mail: isidro.gonzalez@uca.es
5
yeast cells.
957-4166/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0957-4166(02)00415-9

1
682
A. J. Bustillo et al. / Tetrahedron: Asymmetry 13 (2002) 1681–1686
Table 1. Results of baker’s yeast-mediated reduction of 4%- and 3%-chloropropiophenones 1 and 2
Substrate
Reaction time
h)
Substrate
concentration (mM)
Allyl alcohol
(mM)
Hexane (%)
Glucose (mM)
Conversiona (%) e.e. (%)
(
1
24
5.93
5.93
13.20
5.93
5.93
5.93
5.93
–
–
–
67
67
67
–
–
–
–
–
–
1.2
–
505
505
265
505
1009
505
505
9
35
14
21
32
17
54
81
75
77
96
77
92
55
48
48
48
48
48
1
20
2
48
5.93
13.20
5.93
5.93
5.93
–
–
67
67
67
–
–
–
–
505
265
505
1009
505
31
13
22
33
26
80
86
96
67
94
48
48
48
48
1.2
a
Conversion is the % of product in the recovered material.
The enantioselectivities and conversions in the yeast
It has been reported that when the baker’s yeast reduc-
tion of ketones is catalysed by certain enzymes, it
produces (S)-enantiomers while catalysis with different
reduction of the ketones 1 and 2 were investigated
under conventional conditions with heat-treatment at
6
9
5
0°C for 30 min. As shown in Table 1, after incubating
enzymes produces (R)-enantiomers. The inhibition of
1
(1 g) in fermenting baker’s yeast (250 g in 1 L tap
either type of enzyme may thus influence, if not control,
the enantioselectivity of the reduction. We therefore
tried to inhibit the reducing enzymes selectively by
adding inhibitors such as allyl alcohol, as well as a
water) for 48 h, a single transformation product was
2
0
isolated as a colourless oil (35% conversion, [h] =−21
D
(
c 3, CHCl )) with 75% e.e. as shown by HPLC analysis
3
10
using a Chiralcel OD column. This material was shown
small amount of organic solvent to dissolve the
substrate.
to be (S)-(−)-1-(4%-chlorophenyl)propan-1-ol (S)-3
(Scheme 1). The (S)-configuration was determined by
comparing the specific rotation with data from the
literature.
The use of allyl alcohol (67 mM) as an inhibitor led to
a significant increase in enantioselectivity, but once
again the conversion was diminished. While the addi-
tion of 1.2% hexane was not effective in the reduction
of compound 1, it did aid that of compound 2. Finally,
whereas a higher glucose concentration increased the
conversions of the products, it led to a concomitant
decrease in the enantioselectivity of the process (see
Table 1).
7
In the yeast reduction of 3%-chloropropiophenone 2, the
only detectable species present in the incubation mix-
ture were the starting material and a colourless oil,
2
0
(
31% conversion, [h] =−27 (c 5, CHCl )) with 80% e.e.
D 3
by means of HPLC analysis on Chiralcel OD. This
compound was shown to be
(S)-(−)-1-(3%-
chlorophenyl)propan-1-ol (S)-4 (Scheme 1).
2
.2. Lipase-mediated acetylations
It has been shown that increasing the substrate concen-
tration tends to increase the enantiomeric excess in
yeast reductions, presumably because the variation
In order to prepare the (R)-enantiomers of these com-
pounds using commercially available lipases, we
focused on the kinetic resolution of the racemic sec-
ondary alcohols 3 and 4 (prepared by reacting the
commercial ketones 1 and 2, respectively, with sodium
borohydride) by means of an enantioselective transes-
terification reaction using vinyl acetate as an acyl donor
and tert-butyl methyl ether as organic solvent. The
lipases investigated converted the R enantiomers of 3
and 4 in accordance with Kazlauskas’ empirical rule for
8
affects the kinetics of each enzyme (the Km of the
(
R)-enzyme is smaller than that of the (S)-enzyme in
baker’s yeast). With this in mind, we increased the
concentration of the substrate from 5.93 to 13.2 mM.
The result was a slight increase in the e.e. of the
(
S)-enantiomer, but the conversion itself was dimin-
ished (see Table 1).
4
secondary alcohols (Scheme 2). Three different lipases
were employed: lipase PS (from Pseudomonas cepacia),
PPL (porcine pancreas lipase) and CRL (Candida
rugosa lipase). Two of the enzymes tested, lipase PS and
PPL, gave both compounds with high enantioselectivi-
ties under the initial testing conditions (77 h and 22°C).
However, this enhanced selectivity was accompanied by
a fairly low reaction rate. CRL was rejected as a
possible mediator due to the low selectivity and slow
conversions observed when it was used. The results are
summarised in Table 2.
OH
O
Baker's yeast.
Cl
Cl
(
(
S)-3 4'-Cl
S)-4 3'-Cl
1
2
4'-Cl
3'-Cl
Scheme 1.

A. J. Bustillo et al. / Tetrahedron: Asymmetry 13 (2002) 1681–1686
OH
1683
O
OAc
OH
NaBH4
Lipase
Cl
Cl
Cl
+ Cl
MeOH / CH2Cl2
TBME / Vinyl acetate
(
(
R)-5 4'-Cl
R)-6 3'-Cl
3 4'-Cl
4 3'-Cl
1
2
4'-Cl
3'-Cl
3 4'-Cl
4 3'-Cl
S-enantiomer enriched
KOH / MeOH
MnO2 / CH2Cl2
HO
Cl
1
2
4'-Cl
3'-Cl
(R)-3 4'-Cl
(R)-4 3'-Cl
Scheme 2.
Table 2. Results of lipase-mediated acetylation of (9)-1-(4%-chlorophenyl)propan-1-ol, 3 and (9)-1-(3%-chlorophenyl)propan-
-ol, 4
1
Cmpd.
Enz.
Reaction time Temp. (°C)
Conversion
(%)
Acetylated product (R)
Alcohol recovered (S)
E
(h)
e.e. (%)
Yielda (%)
e.e. (%)
Yield (%)
3
PS
PS
PS
PS
77
22
22
22
22
48
22
22
22
22
22
40
22
45
19
25
32
44
25
10
13
18
21
28
16
7
\99
\99
\99
81
38
48
66
82
47
24
28
34
42
45
36
9
23
33
47
64
32
11
15
22
26
28
18
5
79
72
63
54
71
86
86
78
75
73
80
92
93
250
305
317
18
100
168
190
77
PS
98
248
PPL
PPL
PPL
PPL
PPL
PPL
CRL
CRL
77
\99
\99
\99
\99
71
99
72
74
\400
\400
\400
256
8
341
100
168
190
240
77
77
77
6.5
7.2
8
11
6
4
PS
PS
PS
PS
77
100
168
190
77
22
22
22
22
48
22
22
22
22
22
40
22
45
14
17
22
30
21
3
4
6
8
18
3
\99
\99
98
82
99
\99
\99
98
97
96
33
36
44
52
41
7
10
14
17
22
5
17
20
28
35
26
3
4
6
8
11
3
80
75
74
70
74
95
93
91
91
87
92
92
93
\400
220
144
14
312
\400
\400
117
66
PS
PPL
PPL
PPL
PPL
PPL
PPL
CRL
CRL
77
100
168
190
240
77
53
42
6
8
95
73
78
77
77
2
4
4
9
2
4
a
Yield 100% at 50% conversion and after hydrolysis of the acetate derivatives.
In an attempt to increase the conversion rate, different
reaction times were tested (Table 2). The best result was
obtained with lipase PS after 168 h (e.e. >99%, conver-
sion 32% for compound 3).
decreased the enantiomeric excesses, albeit only slightly
(see Table 2). This indicates that temperature may
accelerate the kinetics of the enzyme.
The lipase-mediated esterification of these alcohols
2
0
In order to determine the optimal conditions for trans-
esterification, we also studied the effect of temperature
on the enantiomeric excesses and conversion rate. We
found that transesterification at the optimal tempera-
ture of each enzyme increased the conversion and
afforded the acetate derivatives (R)-5 ([h] =+75 (c 2.3,
D
20
D
CHCl )) and (R)-6 ([h] =+55 (c 5, CHCl )), along
3
3
with the unreacted alcohols 3 and 4. After hydrolysis of
(R)-5 and (R)-6 with potassium hydroxide in methanol,
11
2
0
the enantiopure alcohols (R)-3 ([h] =+27.3 (lit.
D

1
684
A. J. Bustillo et al. / Tetrahedron: Asymmetry 13 (2002) 1681–1686
12 20
2
0
20
D
[
h] =+28)) and (R)-4 ([h] =+30.5 (lit. [h] =+31))
respectively, in 96% e.e. with 22% conversion. The
addition of hexane at a level of 1.2% slightly enhanced
the conversion for compound (S)-3.
D
D
were obtained in high yield (>90%) and with very high
enantiomeric excess (>99%). In both cases the (R)-
configuration was determined by comparing the specific
1
1,12
rotation with data reported in the literature.
Transesterification of racemic alcohols 3 and 4 with
lipases from P. cepacia and porcine pancreas followed
by hydrolysis of the acetate derivatives led to enan-
tiomerically pure alcohols (R)-3 and (R)-4 with high E
values. By prolonging the reaction times, the conver-
sion was significantly improved. A longer reaction time
was needed to obtain similar results with PPL.
The unreacted alcohol derivatives 3 and 4, which were
enriched in the (S)-enantiomer during the esterification
reactions, were oxidised with MnO in order to recover
the starting ketones 4%-chloropropiophenone 1 and 3%-
chloropropiophenone 2 (Scheme 2). This oxidation thus
serves to increase the efficiency of the process.
2
Maximum inhibition against the growth of the phyto-
pathogenic fungus B. cinerea was shown for com-
pounds (R)-(+)-1-(4%-chlorophenyl)propan-1-ol (R)-3
and (R)-(+)-1-(3%-chlorophenyl)propan-1-ol (R)-4. For
this class of compounds, the (R)-enantiomer was found
to have more pronounced antifungal properties.
2
.3. Antifungal assays
Having obtained the enantiopure compounds through
the use of biological methods, we established their
antifungal properties against the growth of B. cinerea
using the ‘poisoned food’ technique. The commercial
fungicide Euparen was used as a standard.
1
3
These results give some indication of the structural
modifications necessary if substrates of this type are to
be further developed as selective fungal control agents
for B. cinerea.
®
Compound (R)-(−)-1-(4%-chlorophenyl)propan-1-ol (R)-
3
exhibited the maximum percent of growth inhibition
followed by its isomer (R)-(−)-1-(3%-chlorophenyl)-
propan-1-ol (R)-4. Alcohol (R)-3 was active even at 10
ppm; at 25 ppm it reduced the growth of the fungus by
4
. Experimental
7
0% after only 6 days. Compound (R)-4 showed a
4
.1. General experimental procedures
slightly lower activity; at the same concentration it
reduced fungal growth by 61% after 6 days. The corre-
sponding (S)-enantiomers displayed a lower inhibitory
activity on B. cinerea, with alcohol (S)-4 being more
active than its corresponding isomer (S)-3.
Optical rotations were determined with a Perkin–Elmer
41 polarimeter. IR spectra were recorded on a Perkin–
2
1
13
Elmer 881 spectrophotometer. H and C NMR mea-
surements were obtained on Varian Gemini 200 and
Varian Unity 400 NMR spectrometers with SiMe as
4
These results indicate that, at least for this class of
compounds, the (R)-enantiomer produces a more pro-
nounced antifungal effect. In addition, the relative posi-
tion of the chloro substituent in the aromatic moiety
was found to be of importance since the para-substi-
tuted compound is more active than the meta-substi-
tuted one.
internal reference. J values are reported in Hz. Mass
spectra were recorded using a VG 12-250 and a VG
Autospec spectrometer at 70 eV. HPLC was performed
with a Hitachi/Merck L-6270 apparatus equipped with
a UV–vis detector (L 4250) and a differential refrac-
tometer detector (RI-71). TLC was performed on
Merck Kiesegel 60 F254, 0.2 mm thick. Silica gel (Merck
9
385) was used for column chromatography. Chemicals
It is worth noting that the acetyl derivatives (R)-5 and
were products of Fluka or Aldrich. All solvents were
freshly distilled. Baker’s yeast was obtained from a
local store. The following enzymes were used in this
work: C. rugosa lipase (Sigma, Type VII, 950 U/mg), P.
cepacia lipase (Amano Pharmaceuticals Co., Japan)
and porcine pancreas lipase (Sigma, Type II). Enan-
tiomeric excesses were determined by means of HPLC
analyses on a chiral column (Chiralcel OD, Daicel,
Japan): 254 nm, 0.8 mL/min, hexane:isopropanol (99:1)
(S)-3 t =46.3 min, (R)-3 t =52.2 min, (S)-4 t =49.7
(
R)-6 were inactive as antifungal agents, which indi-
cates that the hydroxyl group plays an important role
in the inhibitory mechanism.
3. Conclusions
Our attempt to use biological methods to obtain enan-
tiomerically pure sample of 3 and 4 was successful.
Moreover, because of their remarkable stability, the
enzymes employed could actually be re-used. These
methods, which use completely biodegradable biocata-
lysts, are therefore both environmentally acceptable
and inexpensive.
R
R
R
min, (R)-4 t =55.3 min.
R
4.2. Microorganism and antifungal assays
The culture of B. cinerea 2100 was obtained from the
Colecci o´ n Espa n˜ ola de Cultivos Tipo (CECT), Facul-
tad de Biolog ´ı a, Universidad de Valencia, Spain. The
bioassays involved measuring the inhibition of the
radial growth on an agar medium in a Petri dish.
The test compound was dissolved in ethanol to give
The best S selectivity–conversion relationship for the
reduction of ketones 1 and 2 was observed after heat-
treatment of baker’s yeast cells in the presence of allyl
alcohol as an inhibitor. Under these conditions, treat-
ment of 1 and 2 yielded compounds S-3 and S-4,
1
2,13
−
1
final compound concentrations of 10–150 mg L .

A. J. Bustillo et al. / Tetrahedron: Asymmetry 13 (2002) 1681–1686
1685
4
.3. Conventional procedure for the baker’s yeast
1Carom.), 127.5 (d, 1Carom.), 129.6 (d, 1C
), 134.2 (s,
arom.
+
+
transformation
C-1%), 146.6 (s, C-3%); m/z (EI): 172 (M +2, 9), 170 (M ,
2
9), 143 (81), 141 (100), 115 (48), 113 (84), 77 (96).
A mixture composed of baker’s yeast (250 g), D-glucose
(
100 g), and tap water (1 L) was stirred in a 2 L beaker
at 50°C for 30 min, after which time the substrate (1 g,
.93 mmol), which had been dissolved in the minimum
Chiral HPLC analysis of (S)-3 and (S)-4 showed them
to have e.e. of 96%.
5
amount of ethanol, was added dropwise. The reaction
mixture was stirred for 2 days. At the end of this
period, 1 L of ethyl acetate was added and the crude
reaction mixture was filtered through a large B u¨ chner
funnel on a Celite pad, which was later washed with the
same solvent. The aqueous phase was extracted twice
with 0.5 L of ethyl acetate, the organic phase was dried
over Na SO , and the solvent was then evaporated
4.7. Racemic alcohols 3 and 4
Reduction of 4%- and 3%-chloropropiophenone 1 and 2
(20 g, 0.12 mol) with sodium borohydride (7.5 g, 0.2
mol) in methylene chloride:methanol 1:1 (350 ml) at
room temperature gave (±)-1-(4%- and 3%-chloro-
phenyl)propan-1-ol 3 and 4 (19.8 g, 93% and 19.1 g,
1
94%). The H NMR spectra of these products were in
2
4
1
1,12
under reduced pressure to dryness. The residue
obtained was purified by means of column
chromatography.
agreement with those found in the literature.
4.8. General procedure for enzyme-mediated
acetylations
4
.4. Baker’s yeast transformation at different substrate
concentration
A mixture of the racemic alcohol 3 or 4 (1 g, 0.006
mol), lipase (1 g), and vinyl acetate (4 ml) in tert-butyl-
methyl ether (15 ml) was stirred at room temperature.
The residue obtained upon evaporation of the filtered
reaction mixture was chromatographed on a silica gel
column and eluted with hexane:ethyl acetate (95:5). The
first eluted fractions provided the acetate derivative and
the last eluted fractions afforded the unreacted starting
material. Detailed results of the enzyme-mediated
acetylations are reported in Table 2.
A mixture of baker’s yeast (20 g), water (380 ml), and
glucose (20 g) was stirred at 50°C for 30 min. The
substrate (843 mg, 13.2 mmol/L) was added to the
mixture and the reaction was allowed to stir for an
additional 48 h. The work-up procedure was essentially
the same as that described above. The results are listed
in Table 1.
4
.5. Baker’s yeast transformation in the presence of
several additives
4.9. (R)-(+)-1-(4%- and 3%-Chlorophenyl)propyl acetates
(
R)-5 and (R)-6
A mixture of baker’s yeast (250 g), water (1 L), and
glucose (100 g, 0.505 mol or 200 g, 1.009 mol) was
stirred at 50°C for 30 min. The substrate (1 g, 5.93
mmol) was dissolved in (8 ml, 67 mmol) of allyl alcohol
and hexane (12 ml, 1.2%) and was then added dropwise
to the mixture. The reaction was then stirred for 48 h.
The work-up procedure was essentially the same as that
described above. The results are shown in Table 1.
After a reaction time of 168 h, lipase PS-mediated
acetylation of racemic chlorophenylpropanols 3 and 4
(1 g, 0.006 mol) gave enantiopure acetate derivatives
20
(R)-5 (0.375 g, 33%) [h] =+75 (c 2.3, CHCl ) and
D
3
2
0
(R)-6 (0.250 g, 22%) [h] =+55 (c 5, CHCl ).
D
3
1
(R)-5: IR (film): 2972, 1738, 1238, 822; H NMR (200
MHz, CDCl ) l 0.84 (3H, t, J=7.3 Hz, H-3), 1.60–2.00
3
4
.6. (S)-(−)-Chlorophenylpropanols (S)-3 and (S)-4
(2H, m, H-2), 2.05 (3H, s, COCH3
Hz, H-1), 7.15–7.35 (4H, m, Harom.); C NMR (50
MHz, CDCl ) l 9.8 (q, C-3), 21.2 (q, COCH ), 29.1 (t,
6 ), 5.59 (1H, t, J=6.7
13
Baker’s yeast reduction of 1 and 2 (1 g/L) yielded (S)-3
and (S)-4, respectively.
6
3
3
C-2), 76.6 (d, C-1), 127.9 (d, 2Carom.), 128.5 (d, 2Carom.),
33.5 (s, C-1%), 139.0 (s, C-4%), 170.3 (s, CO); m/z (EI):
1
6
+
2
0
7
20
D
+
+
(
(
S)-3: [h] =−30.3 (c 3, CHCl ) (lit. [h] =−28); IR
214 (M +2, 3), 212 (M , 8), 185 (M +2−29, 6), 183
D
3
1
+
+
+
film): 3364, 2965, 1492, 825; H NMR (200 MHz,
(M −29, 19), 172 (M +2−COCH , 4), 170 (M −
3
CDCl ) l 0.84 (3H, t, J=7.5 Hz, H-3), 1.50–1.85 (2H,
COCH , 11), 143 (28), 141 (98), 127 (21), 125 (65), 117
3
3
m, H-2), 3.06 (1H, s, OH), 4.47 (1H, t, J=6.7 Hz, H-1),
(100), 77 (32).
13
7.15–7.30 (4H, m, Harom., J=8.3 Hz, J=8.9 Hz);
C
1
NMR (50 MHz, CDCl ) l 9.8 (q, C-3), 31.7 (t, C-2),
(R)-6: IR (film): 2971, 1738, 1236, 785, 696; H NMR
3
7
5.0 (d, C-1), 127.3 (d, 2Carom.), 128.3 (d, 2Carom.), 132.8
s, C-1%), 142.8 (s, C-4%); m/z (EI): 172 (M +2, 16), 170
(200 MHz, CDCl ) l 0.88 (3H, t, J=7.5 Hz, H-3),
3
+
(
(
1.70–2.00 (2H, m, H-2), 2.09 (3H, s, COCH3
6
), 5.62 (1H,
+
13
M , 50), 143 (82), 141 (100), 115 (59), 113 (85), 77 (80).
t, J=6.7 Hz, H-1), 7.15–7.35 (4H, m, H
); C NMR
arom.
(
50 MHz, CDCl ) l 9.7 (q, C-3), 21.0 (q, COC6 H ), 29.2
3
3
2
0
(
1
S)-4: [h] =−27.4 (c 5, CHCl ); IR (film): 3362, 2966,
(t, C-2), 76.4 (d, C-1), 124.7 (d, 1Carom.), 126.5 (d,
1Carom.), 127.8 (d, 1Carom.), 129.6 (d, 1Carom.), 134.2 (s,
D
3
1
492, 825; H NMR (200 MHz, CDCl ) l 0.89 (3H, t,
3
J=7.5 Hz, H-3), 1.60–1.90 (2H, m, H-2), 2.04 (1H, s,
OH), 4.56 (1H, t, J=6.4 Hz, H-1), 7.15–7.35 (4H, m,
C-1%), 142.5 (s, C-3%), 170.2 (s, C6 O); m/z (EI): 214
+ + + +
(M +2, 3), 212 (M , 9), 185 (M +2−29, 5), 183 (M −29,
1
3
+
+
3 3
Harom.); C NMR (50 MHz, CDCl ) l 9.9 (q, C-3), 31.9
16), 172 (M +2−COCH , 38), 170 (M −COCH , 100),
3
(
t, C-2), 75.3 (d, C-1), 124.1 (d, 1Carom.), 126.1 (d,
143 (18), 141 (70), 127 (24), 125 (70), 117 (75), 77 (39).

1
686
A. J. Bustillo et al. / Tetrahedron: Asymmetry 13 (2002) 1681–1686
4
.10. (R)-(+)-1-(4%- and 3%-Chlorophenyl)propan-1-ol
Acknowledgements
(
R)-3 and (R)-4
Treatment of acetate derivatives (R)-5 and (R)-6 (0.110
g, 0.52 mmol) with potassium hydroxide (0.1 g, 1.8
mmol)) in methanol solution (35 ml) at room tempera-
ture afforded enantiopure alcohol derivatives (R)-3 (79
This work was supported by a grant from D.G.I.C.Y.T.
AGL2000-0635-C02-01.
20
References
mg, 91%) and (R)-4 (83 mg, 94%) showing [h] ((R)-
D
1
1
20
20
3
)=+27.3 (c 2.4, CHCl ) (lit. [h] =+28) and [h]
3 D D
12 20
1. The Biology of Botrytis; Coley Smith, J. R.; Verhoeff, K.;
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Jarvis, W. R., Eds.; Academic Press: London, 1980; pp.
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1
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(
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6
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3
chemistry 1994, 35, 331; (c) Echeverri, F.; Torres, F.;
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1
3
C NMR (50 MHz, CDCl ) l 9.9 (q, C-3), 31.8 (t,
3
44, 255.
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3. (a) Fronza, G.; Fuganti, C.; Grasselli, P.; Mele, A. J.
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1
32.9 (s, C-1%), 142.9 (s, C-4%); m/z (EI): 172 (M +2, 4),
+
70 (M , 14), 143 (55), 141 (100), 115 (61), 113 (95), 77
(
87).
1
(
(
R)-4: IR (film): 3364, 2966, 1432, 784, 698; H NMR
200 MHz, CDCl ) l 0.92 (3H, t, J=7.5 Hz, H-3),
3
1
.60–1.90 (2H, m, H-2), 2.06 (1H, s, OH), 4.58 (1H, t,
4017.
13
J=6.7 Hz, H-1), 7.15–7.40 (4H, m, Harom.); C NMR
50 MHz, CDCl ) l 9.9 (q, C-3), 31.9 (t, C-2), 75.3 (d,
4
. (a) Kazlauskas, R. J.; Weissfloch, A.; Rappaport, A. T.;
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3
C-1), 124.1 (d, 1Carom.), 126.1 (d, 1Carom.), 127.5 (d,
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1
arom.
+
5
6
7
8
9
+
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1
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1
The H NMR spectra of these enantiopure compounds
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. Wipf, B.; Kupfer, E.; Bertazzi, R.; Leuenberger, H. G.
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(
1.5 equiv.) in methylene chloride solution (50 ml) at
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dez-Gal a´ n, R. J. Chem. Ecol. 1994, 20, 2631.
room temperature. After purification on a silica gel
column, eluting with hexane:ethyl acetate (9:1), the
derivatives afforded the 4%- and 3%-chloropropiophe-
nones 1 and 2 (97% yield). The H NMR spectra of
these compounds were in agreement with those of the
commercial products.
1