Synthesis of the deuterated sex pheromone components of the grape borer, xylotrechus pyrrhoderus

Article abstract of DOI:10.1271/bbb.90348

Adult males of the grape borer, Xylotrechus pyrrho- derus, secrete (S)-2-hydroxy-3-octanone [(S)-1] and (2S,3S)-2,3-octanediol [(2S,3S)-2] from their nota of prothoraces as sex pheromone components. Their structural similarity suggests that one of them is the biosynthetic precursor of the other component. In order to confirm the biochemical conversion, deuterated derivatives of both components were synthesized by starting from a Wittig reaction between hexanal and an ylide derived from D₅-iodoethane and ending with enantiomeric resolution by chiral HPLC. The molecular ions of 1 and 2 could scarcely be detected by using a GC- MS analysis, and the labeled compounds showed similar mass spectra to the unlabeled pheromone components. However, several fragment ions, including four deuterium atoms, were observed in the mass spectra of their acetate derivatives, indicating that the conversion could be confirmed by examining a compound with the diagnostic ions after acetylation of the volatiles collected from insects treated with the labeled precursors.

Full text of DOI:10.1271/bbb.90348

Biosci. Biotechnol. Biochem., 73 (10), 2252–2256, 2009
Synthesis of the Deuterated Sex Pheromone Components of the Grape Borer,
Xylotrechus pyrrhoderus
1
1
2
2
1;y
Ryutaro KIYOTA, Rei YAMAKAWA, Kikuo IWABUCHI, Keita HOSHINO, and Tetsu ANDO
1
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology,
Koganei, Tokyo 184-8588, Japan
2
Department of Applied Biological Science, Faculty of Agriculture, Tokyo University of Agriculture and Technology,
Fuchu, Tokyo 183-8509, Japan
Received May 13, 2009; Accepted June 20, 2009; Online Publication, October 7, 2009
[doi:10.1271/bbb.90348]
Adult males of the grape borer, Xylotrechus pyrrho-
derus, secrete (S)-2-hydroxy-3-octanone [(S)-1] and
2S,3S)-2,3-octanediol [(2S,3S)-2] from their nota of
thetic step in Scheme 1 was examined by using
unlabeled iodoethane. Namely, a Wittig reaction be-
tween hexanal and an ylide derived from iodoethane
produced (Z)-2-octene (3) which included about 30% of
the undesired (E)-isomer. To prevent the volatile
products from being lost, the mixture was treated with
MCPBA without any purification, and cis-2,3-epoxyoc-
tane (4) contaminated with the trans-isomer was
obtained. The epoxides were transformed to a 3:1:3:1
mixture of threo-2-acetoxy-3-octanol (5), its erythro-
isomer, threo-3-acetoxy-2-octanol (6), and its erythro-
isomer by heating in acetic acid. While separation of the
threo- and erythro-isomers was not accomplished, the
positional isomers were separable by MPLC with a
Lobar column. The former two 3-octanols, which eluted
faster than the latter two 2-octanols, were oxidized to 2-
acetoxy-3-octanone (7) by PCC after MPLC separation.
The acetate was hydrolyzed by K2CO3 to yield racemic
2-hydroxy-3-octanone (1). On the other hand, the
acetoxy groups of 6 and the erythro-isomer were
methanolysed to yield a 3:1 mixture of threo-2,3-
octanediol (2) and its erythro-isomer, which were
separable by HPLC with a silica gel column function-
alized with the 3-(4-nitrophenyl)propyl group (an NO2
column). The threo-diol (2), which eluted faster than the
minor erythro-isomer, was isolated by HPLC. Unlabeled
1 and 2 showed identical spectroscopic data with those
(
prothoraces as sex pheromone components. Their
structural similarity suggests that one of them is the
biosynthetic precursor of the other component. In order
to confirm the biochemical conversion, deuterated
derivatives of both components were synthesized by
starting from a Wittig reaction between hexanal and an
ylide derived from D5-iodoethane and ending with
enantiomeric resolution by chiral HPLC. The molecular
ions of 1 and 2 could scarcely be detected by using a GC-
MS analysis, and the labeled compounds showed similar
mass spectra to the unlabeled pheromone components.
However, several fragment ions, including four deute-
rium atoms, were observed in the mass spectra of their
acetate derivatives, indicating that the conversion could
be confirmed by examining a compound with the
diagnostic ions after acetylation of the volatiles collected
from insects treated with the labeled precursors.
Key words: sex pheromone; Cerambycidae; deuterated
precursor; pheromone biosynthesis; long-
horned beetle
The grape borer, Xylotrechus pyrrhoderus Bates
Coleoptera: Cerambycidae), is a harmful pest of grape-
(
2
,3)
vines in Japan. The mating behavior of this long-horned
beetle is mediated by sex pheromones secreted by both
of previous publications.
Resolution of the stereoisomers of 1, 2, and their
related compounds was examined by chiral HPLC
conducted under normal-phase conditions with a Chir-
alpak AS-H or AD-H column and under reversed-phase
condition with a Chiralcel OJ-R column (Table 1).
While no enatiomeric separation was achieved by the
OJ-R column, the AS-H column accomplished resolu-
tion of 1 and 2, and the AD-H column, that of 1 and the
erythro-isomer of 2. Dextrorotatory (S)-1 was eluted
faster than levorotatory (R)-1 from both normal-phase
chiral columns, and levorotatory (2S,3S)-2 eluted faster
than dextrorotatory (2R,3R)-2.
1
)
the male and female adults. During the first phase, the
female is attracted over a long range by the male
pheromone which is composed of (S)-2-hydroxy-3-
octanone [(S)-1] and (2S,3S)-2,3-octanediol [(2S,3S)-2]
2)
(
Fig. 1). It has been reported that these compounds are
secreted from glands on the prothorax surface, although
their biosynthetic pathways are still unknown. The
structural similarity of 1 and 2 suggests that one of them
is the biosynthetic precursor of the other component. In
order to confirm the biosynthetic conversion, deuterated
derivatives of both components were synthesized by
using deuterated iodoethane.
By applying this established method, [1,1,1,2]-D4-(S)-
and [1,1,1,2]-D4-(2S,3S)-2 were synthesized by start-
1
Results and Discussion
ing from D5-iodoethane (Scheme 1). In addition to the
final products, the structures of the synthetic intermedi-
ates, including four D atoms, were confirmed by NMR.
Before preparing deuterated pheromone components,
1,1,1,2]-D -(S)-1 and [1,1,1,2]-D -(2S,3S)-2, each syn-
1
[
The H signals of a methyl at the 1-position and methine
4
4
y
To whom correspondence should be addressed. Tel/Fax: +81-42-388-7278; E-mail: antetsu@cc.tuat.ac.jp

Deuterated Sex Pheromone of a Long-Horned Beetle
2253
at the 2-position disappeared in each spectrum, and
meric excess. Although the unselective ring opening of
epoxide 4 produced two acetoxy alcohols (5 and 6), they
could be used for the syntheses of 1 and 2 after MPLC
separation.
1
3
the C signals at the 1- and 2-positions were also
undetected in the spectra measured with a usual
scanning number. These signals are indicated with
asterisks in the data given in the Experimental section.
Several synthetic methods have been published for (S)-
On the other hand, a GC-MS analysis showed that all
D -compounds flowed out slightly faster than the
4
2–5)
1
,
but they do not seem to be adaptable for labeling
corresponding unlabeled compounds (see the Experi-
mental section). In the deuterated compounds with an
with deuterium. Our strategy to resolve the racemic
mixture by chiral HPLC was simple, and both stereo-
isomers could be easily obtained with a high enantio-
þ
acetoxy group, 5–7, [M-60] ions were detected at m=z
positions 4 mass units larger than those of the
corresponding unlabeled compounds. However, the
mass spectra of D4-1 and D4-2 were almost the same
as those of the unlabeled compounds, as shown in
Fig. 2A–D, indicating that fragment ions had mainly
been produced from the part including no D atoms. The
O
OH
þ
OH
OH
2S,3S)-2
M ions of 1 and 2 could scarcely be detected by using
the analysis in the EI mode, and it was difficult to clearly
observe the biochemical conversion of the labeled
precursors at the pheromone gland, including the
endogenous natural pheromone components. This prob-
lem was overcome by comparing the mass spectra of the
(
S)-1
(
Fig. 1. Male Sex Pheromone Components of the Grape Borer,
(
[
S)-2-Hydroxy-3-octanone [(S)-1] and (2S,3S)-2,3-Octanediol
(2S,3S)-2].
Z
cis
O
D
O D
a
b
CD3
CD3
H
D -3
D -4
4
4
threo
OH
O
O
D
f, g
e
CD3
OAc
CD3
OAc
CD3
OH
D
D
D -5
D -7
D -(S)-1
c, d
4
4
4
threo
OAc
CD3
OH
f, h
CD3
D
OH
D
OH
D -6
D -(2S,3S)-2
4
4
Scheme 1. Synthetic Routes for Deuterated Derivatives of the Pheromone Components of the Grape Borer, D4-(S)-1 and D4-(2S,3S)-2.
a, CD3CD=PPh3/THF; b, 3-chloroperbenzoic acid (MCPBA)/CH2Cl2; c, AcOH; d, MPLC; e, pyridinium chlorochromate (PCC)/CH2Cl2;
f, K2CO3/MeOH; g, chiral HPLC; h, 1) achiral HPLC, 2) chiral HPLC
Table 1. Enantiomeric Separation of 2-Hydroxy-3-octanone (1), 3-Hydroxy-2-octanone, threo-2,3-Octanediol (2), and the erythro-Isomer in Chiral
a
HPLC Columns
Normal-phase
Reversed-phase
d
Compound
Chiralpak AS-Hb
Separation factor (ꢀ)
Chiralpak AD-Hc
Separation factor (ꢀ)
Chiralcel OJ-R
tR (min)
tR (min)
tR (min)
2
3
2
-Hydroxy-3-octanone (1)
(
(
þ)-(S)-Isomer
ꢀ)-(R)-Isomer
19.88
20.79
1.07
1.16
18.79
22.46
1.33
1.08
16.67
e
ꢁ
f
-Hydroxy-2-octanone
(
(
ꢀ)-Isomer
þ)-Isomer
22.00
24.50
18.50
19.33
16.46
e
ꢁ
,3-Octanediol
threo (2)
(ꢀ)-(S,S)-Isomer
þ)-(R,R)-Isomer
(ꢀ)-Isomer
þ)-Isomer
16.75
18.08
19.04
1.12
1.00
25.21
e
1.00
1.04
19.17
e
(
ꢁ
ꢁ
erythro
26.63
27.46
15.96
e
e
(
ꢁ
ꢁ
aEach deuterated derivative showed almost the same chromatographic behavior as that of the corresponding unlabeled compound.
bEluent: 2% and 5% 2-propanol in hexane for ketols and diols, respectively. Flow rate: 0.50 ml/min.
cEluent: 2% and 4% 2-propanol in hexane for ketols and diols, respectively. Flow rate: 0.50 ml/min.
dEluent: 20% and 10% CH3CN in water for ketols and diols, respectively. Flow rate: 0.50 ml/min.
eThe racemic compound showed one peak.
f
The racemic compound was synthesized from a mixture of 6 and the erythro-isomer.

2254
R. KIYOTA et al.
O
87
71
O
A
99
E
99
126
-H)
(
71
OAc
30 (+H)
OH
44
99
71
1
55
126 130
143
1
87
186
50
100
150
50
100
150
200
m/z
m/z
99
99
B
F
71
71
134
130
147
148
190
55
91
50
100
150
50
100
150
200
m/z
m/z
87
7
5
143
OH
87
AcO
C
D
83
G
H
5
5
1
28 143
OH
OAc
187
1
01
101
83
116
117
75
50
100
150
50
100
150
200
m/z
m/z
91
83
55
143
83
116
132
101
79
121
191
50
100
150
50
100
150
m/z 200
m/z
Fig. 2. Mass Spectra of Unlabeled and Labeled Pheromone Components of the Grape Borer and Their Acetate Derivatives.
A, 2-hydroxy-3-octanone (1); B, [1,1,1,2]-D4-1; C, threo-2,3-octanediol (2); D, [1,1,1,2]-D4-2; E, acetate of 1 (¼ 7); F, acetate of [1,1,1,2]-
D4-1 (¼ D4-7); G, diacetate of 2; H, diacetate of [1,1,1,2]-D4-2
labeled and unlabeled pheromone components after
acetylation. Fragment ions at m=z 130 and 87 in the
acetate of 1 (¼ 7) were shifted to m=z 134 and 91 in the
acetate of D -1 (¼ D -7), respectively, and ions at m=z
compounds, C6 and C10 homologous pheromones have
been identified from some long-horned beetles in
6
–8)
Xylotrechus and other genera.
pathways, however, have never been investigated.
Their biosynthetic
9
)
4
4
1
1
87, 128, and 87 in the diacetate of 2 were shifted to m=z
Elucidation of the steps for the construction of the
2-hydroxy-3-one structure that is universally present in
the pheromones of long-horned beetles is an interesting
future subject for a better understanding of the mating
communication systems of these beetles.
91, 132, and 91 in the diacetate of D -2, respectively
4
(
Fig. 2E–H). Since 1 was easily isomerized to 3-
hydroxy-2-ketone by heat, it is known that differentia-
tion between naturally occurring components and by-
products by GC-MS is difficult.2,5,6) Fortunately, no
isomerization of 7 was apparent with the GC-MS
analysis.
The adults of X. pyrrhoderus appear once a year, and
preliminary experiments with D4-(S)-1 and D4-(2S,3S)-2
were carried out in the summer of 2008. Each compound
was topically applied to the prothoraces of adult males,
and the collected volatiles were analyzed by GC-MS
with reference to the foregoing diagnostic ions after
acetylation. While no conversion of the diol into the
ketol could be detected, the ketol was reproducibly
converted into the diol, indicating biosynthesis of
Experimental
Spectroscopy and chromatography. H- and 13C-NMR spectra were
recorded by a Delta 2 Fourier transform spectrometer (Jeol, Tokyo,
Japan) at 399.8 and 100.5 MHz, respectively, for CDCl3 solutions
containing TMS as an internal standard. GC-MS was conducted in the
EI mode (70 eV) with an HP5973 mass spectrometer (Hewlett-
Packard) equipped with a split/splitless injector and a DB-23 column
1
(
USA). The column temperature program was 50 C for 2 min, 4 C/min
0.25 mm ID ꢂ 30 m, 0.25 mm film; J & W Scientific, Folsom, CA,
ꢃ
ꢃ
ꢃ
ꢃ
ꢃ
ꢃ
to 150 C, 10 C/min to 220 C, and 220 C for 10 min. The carrier gas
was He. A high-resolution MS (HR-MS) analysis was performed with
a JMS-MS700V mass spectrometer (Jeol). IR spectra were recorded as
a thin film (neat liquid) with a FT/IR-350 (Jasco, Tokyo, Japan). The
specific rotation of each CHCl3 solution was measured with a Jasco
DIP-4 polarimeter. All LC analyses employed the same system
composed of a pump (PU-980, Jasco), an RI detector (RI-98SCOPE,
Labo System, Tokyo, Japan), and an integrator (807-IT, Jasco). MPLC
separation of 2-acetoxy-3-octanol from 3-acetoxy-2-octanol was
accomplished with a Lobar column (Merck Lichroprep Si 60, 10 mm
ID ꢂ 24 cm, 40–63 mm) which was eluted with 20% THF in hexane at a
flow rate of 2.0 ml/min. Separation of threo-octanediol from the
erythro-isomer used achiral HPLC equipped with a functionalized
(
1
2S,3S)-2 via (S)-1. When the male was treated with
0 mg of D4-(S)-1, the exogenous deuterated diol
represented about 10% of the diol recovered as a
volatile. In the summer of 2009, we will examine this
biochemical conversion again in detail, also using their
antipodes and some other related compounds in order to
examined the substrate specificity of the enzyme that is
expected to occur in the pheromone gland. These results
will be reported elsewhere. In addition to the C8

Deuterated Sex Pheromone of a Long-Horned Beetle
2255
ꢄ
silica column (Senshu-pak NO2-3151-N, 8 mm ID ꢂ 15 cm) which was
eluted with 30% EtOAc in hexane at a flow rate of 1.0 ml/min.
Resolution of the enantiomers by chiral HPLC was examined with the
following three columns (see Table 1 for the eluent and flow rate):
Chiralpak AD-H (4.6 mm ID ꢂ 25 cm; Daicel Chemical Industry,
Osaka, Japan), Chiralpak AS-H (4.6 mm ID ꢂ 25 cm; Daicel Chemical
Industry), and Chiralcel OJ-R (4.6 mm ID ꢂ 15 cm; Daicel Chemical
Industry).
3.80 (1H, dq, J ¼ 5, 6.5 Hz), 4.77 [1H, ddd, J ¼ 7:5, 5, 5 Hz (dd,
1
3
ꢄ
J ¼ 7:5, 5 Hz in D4-6)]; C-NMR ꢁ: 14.0, 19.5 , 21.10, 22.5, 25.0,
ꢄ
ꢀ1
30.4, 31.70, 68.6 , 77.9, 171.2; IR ꢂmax cm : 3456, 2931, 2862, 1738,
þ
1373, 1244, 1026, GC-MS m=z: tR 23.27 min, 128 (1%, [M-60] ), 88
þ
(100%) [D4-6: tR 23.17 min, 132 (1%, [M-60] ), 92 (100%)]. erythro-
Isomer of 6: 1H-NMR ꢁ: 0.88 (3H, t, J ¼ 7 Hz), 1.16 (3H, d,
ꢄ
ꢄ
J ¼ 6:5 Hz), 1.25–1.5 (8H, m), 2.10 (3H, s), 3.88 (1H, dq, J ¼ 3,
1
3
6.5 Hz), 4.87 [1H, m (dd, J ¼ 9, 4.5 Hz in D4-compound)]; C-NMR
ꢄ
ꢄ
ꢁ
: 14.0, 17.7 , 21.15, 22.5, 25.3, 29.3, 31.66, 69.2 , 78.1, 171.5; GC-
þ
MS m=z: tR 23.50 min, 128 (1%, [M-60] ), 88 (100%) [D4-compound:
cis-2,3-Epoxyoctane (4). A mixture of iodoethane (2.03 g,
3 mmol), triphenylphosphine (3.93 g, 15 mmol), and benzene (30 ml)
þ
tR 23.40 min, 132 (1%, [M-60] ), 92 (100%)].
1
ꢃ
was heated overnight at 100 C while refluxing and stirring. The
crystals formed were collected by filtration and dried in vacuum to give
a phosphonium salt (4.77 g, 80%). To a suspension of this salt (2.09 g,
2
-Acetoxy-3-octanone (7). PCC (100 mg) was added by bits to a
stirred CH2Cl2 solution (40 ml) of threo-2-acetoxy-3-octanol (5) mixed
with the erythro-isomer (74 mg, 0.39 mmol) at rt. After stirring for 4 h,
the reaction mixture was poured into hexane (100 ml), and the dark
precipitate was removed by filtration. The solvent was evaporated, and
residual materials were purified by column chromatography with silica
gel (5 g, eluent of benzene/EtOAc 10:0 to 8:2) to give 7 (56 mg,
5 mmol) in dry THF (15 ml) in a three-necked flask cooled in an ice
bath, butyllithium (1.6 M solution in hexane, 3.1 ml, 5 mmol) was
added dropwise under N2 to form an ylide. After 30 min, hexanal
(
0.50 g, 5.5 mmol) dissolved in dry THF (0.5 ml) was added to the ylide
solution. The reaction mixture was stirred for 1 h at room temperature
rt) and poured into water, and the produced 2-octene [a mixture of 3
0
1
.30 mmol, 77%). In a similar manner and yield, D4-7 was synthesized.
ꢄ
(
H-NMR ꢁ: 0.89 (3H, t, J ¼ 7 Hz), ꢁ1:3 (4H, m), 1.39 (3H, d,
J ¼ 7 Hz), 1.59 (2H, ddt, J ¼ 7:5, 7.5, 7.5 Hz), 2.14 (3H, s), 2.41 (1H,
and its (E)-isomer] was extracted with pentane (3 ꢂ 15 ml). After most
of the solvent had carefully been removed by evaporation, the
concentrated products were successively mixed with CH2Cl2 (20 ml)
and MCPBA (77%, 0.67 g, 3.0 mmol) while stirring in an ice bath. The
ꢄ
dt, J ¼ 17:5, 7.5 Hz), 2.52 (1H, dt, J ¼ 17:5, 7.5 Hz), 5.09 (1H, q,
1
3
ꢄ
ꢄ
J ¼ 7Hz); C-NMR ꢁ: 13.9, 16.2 , 20.8, 22.5, 22.9, 31.3, 38.2, 74.6 ,
max
170.4, 207.9; IR ꢂ cm 1: 2935, 2873, 1745, 1730, 1373, 1236, 1047;
ꢀ
ꢃ
mixture was stirred at 0 C for 1 h and at rt for 2 h, poured into water,
and extracted with pentane. Column chromatography with silica gel
þ
þ
GC-MS m=z: tR 20.31 min, 186 (0.5%, M ), 126 (6%, [M-60] ), 99
þ
(
100%) [D4-7: tR 20.23 min, 130 (7%, [M-60] ), 99 (100%)]. HR-MS
(1 g, eluent of pentane) gave 2,3-epoxyoctane, a mixture of cis-2,3-
epoxyoctane (4) and its trans-isomer in an approximate 3:1 ratio
þ
m=z ([M-43] ) of 7: calcd. for C8H15O2, 143.1072; found, 143.1049.
þ
HR-MS m=z ([M-43] ) of D4-7: calcd. for C8H11D4O2, 147.1319;
found, 147.1342.
(
0.29 g, 45% from the phosphonium salt). Starting from D5-iodoethane
99.5 atom% D, Aldrich), a mixture of [1,1,1,2]-D4-4 and its trans-
(
isomer (0.26 g, 39%) was synthesized in the similar manner and yield.
1
ꢄ
4
: H-NMR ꢁ: 0.91 (3H, t, J ¼ 7 Hz), 1.26 (3H, d, J ¼ 5:5 Hz), 1.3–
2-Hydroxy-3-octanone (1). A mixture of 7 (56 mg), K2CO3 (10 mg),
and MeOH (3 ml) was stirred at rt for 2 h. After the reaction mixture
had been poured into water (10 ml), the product was extracted with
hexane and purified by column chromatography with silica gel (3 g,
eluent of benzene/EtOAc 10:0 to 7:3) to give 1 (37 mg, 0.27 mmol,
ꢄ
1
.55 (8H, m), 2.89 [1H, dt J ¼ 4:5, 6 Hz (t, J ¼ 6 Hz in D4-4)], 3.04
13
ꢄ
(
1H, dq, J ¼ 4:5, 5.5 Hz); C-NMR ꢁ: 13.2 , 14.0, 22.6, 26.2, 27.5,
ꢄ
3
1.72, 52.7 , 57.2; GC-MS m=z (relative intensity): tR 6.95 min, 113
þ
(
[
(
4%, [M-15] ), 85 (36%), 56 (100%) [D4-4: tR 6.88 min, 114 (3%,
þ
1
1
M-18] ), 89 (32%), 56 (100%)]. trans-Isomer of 4: H-NMR ꢁ: 0.90
ꢄ
90%). In a similar manner and yield, D4-1 was synthesized. H-NMR
ꢄ
3H, t, J ¼ 7 Hz), 1.29 (3H, d, J ¼ 5 Hz), 1.3–1.55 (8H, m), 2.62 [1H,
ꢁ: 0.90 (3H, t, J ¼ 7 Hz), ꢁ1.3 (4H, m), 1.38 (3H, d, J ¼ 7 Hz), 1.63
ꢄ
td, J ¼ 5:5, 2 Hz (t, J ¼ 5:5 Hz in D4-compound)], 2.74 (1H, dq,
(2H, ddt, J ¼ 7:5, 7.5, 7.5 Hz), 2.43 (1H, dt, J ¼ 17, 7.5 Hz), 2.52 (1H,
1
3
ꢄ
ꢄ
ꢄ
13
ꢄ
J ¼ 2, 5 Hz); C-NMR ꢁ: 14.0, 17.7 , 22.6, 25.7, 31.68, 32.0, 54.7 ,
dt, J ¼ 17, 7.5 Hz), 4.24 (1H, q, J ¼ 7Hz); C-NMR ꢁ: 14.0, 19.9 ,
þ
ꢄ
ꢀ1
5
9.9; GC-MS m=z: tR 6.09 min, 113 (4%, [M-15] ), 85 (36%), 56
22.4, 23.3, 31.4, 37.5, 72.6 , 212.8; IR ꢂmax cm : 3454, 2931, 2871,
þ
þ
(
(
100%) [D4-compound: tR 6.01 min, 114 (4%, [M-18] ), 89 (30%), 56
100%)]. The NMR signals indicated with an asterisk were not
1714, 1373, 1122, 1053; GC-MS m=z: tR 16.86 min, 144 (0.5%, M ),
þ
99 (100%) [D4-1: tR 16.77 min, 148 (0.5%, M ), 99 (100%)]. With
a GC-MS analysis, thermally isomerized products, 3-hydroxy-2-
detected in the corresponding deuterated compound.
þ
octanone [tR 16.98 min, 144 (0.2%, M ), 101 (24%), 83 (63%), 55
(
100%)] derived from 1 and D4-3-hydroxy-2-octanone [tR 16.88 min,
þ
threo-2-Acetoxy-3-octanol (5) and threo-3-acetoxy-2-octanol (6).
cis-Epoxide 4 mixed with the trans-isomer (200 mg) was dissolved in
1
were detected.
47 (0.1%, M ), 101 (30%), 83 (70%), 55 (100%)] derived from D4-1,
,5,6)
2
ꢃ
The resolution of these racemic mixtures by chiral
HPLC equipped with an AD-H column gave (S)-1, D4-(S)-1, and their
AcOH (1.0 ml). After stirring at 55 C for 6 h, the mixture was poured
into water and extracted with Et2O. While the exact mixing ratio of
produced alcohols could not be obtained with a GC-MS analysis
because of thermal isomerization, an NMR analysis indicated that the
crude product included 5, the erythro-iosmer of 5, 6, and the erythro-
isomer of 6 in a ratio of 3:1:3:1. The former two 3-octanols and the
latter two 2-octanols showed a signal split to a double quartet at ꢁ
enantiomers. ½ꢀꢅD23: (S)-1, 65.8 (c ¼ 0:75, CHCl3); (R)-1, ꢀ68:0
ꢃ
ꢃ
ꢃ
(
c ¼ 0:74, CHCl3); D4-(S)-1, 57.5 (c ¼ 0:63, CHCl3); D4-(R)-1,
ꢃ
ꢀ
57:6 (c ¼ 0:58, CHCl3).
threo-2,3-Octanediol (2). A mixture of threo-3-acetoxy-2-octanol
ꢁ
4:8 ppm and ꢁ3:8 ppm, respectively. Two adjacent spots were
detected by TLC of the mixture (benzene/EtOAc 5:1, Rf 0.32 and
.24), and the 3-octanols (74 mg, 37%, tR 20.3 min) were completely
(6) associated with the erythro-isomer (67 mg, 0.36 mmol), K2CO3
(10 mg), and MeOH (3 ml) was stirred at rt for 2 h. After the reaction
mixture had been poured into water (10 ml), the product was extracted
with Et2O and purified by column chromatography with silica gel (3 g,
eluent of benzene/EtOAc 10:0 to 4:6) to give a threo-diol (2)
associated with the erythro-isomer (44 mg, 0.30 mmol, 83%). Achiral
HPLC separation gave 2 (tR 18.58 min, 28 mg) and the erythro-isomer
(tR 22.00 min, 9 mg). In a similar manner and yield, D4-2 was
0
separated from the 2-octanols (67 mg, 34%, tR 30.3 min) by MPLC.
From the deuterated epoxides, a mixture of the corresponding
deuterated alcohols was obtained in a similar manner and yield. 5:
1
ꢄ
H-NMR ꢁ: 0.89 (3H, t, J ¼ 7 Hz), 1.24 (3H, d, J ¼ 6:5 Hz), 1.25–1.5
ꢄ
(
8H, m), 2.08 (3H, s), 3.53 [1H, m, (dd, J ¼ 7:5, 4 Hz, in D4-5)], 4.83
13
ꢄ
1
ꢄ
(
1H, dq, J ¼ 5, 6.5 Hz); C-NMR ꢁ: 14.0, 16.4 , 21.26, 22.6, 25.2,
synthesized. 2: H-NMR ꢁ: 0.90 (3H, t, J ¼ 7 Hz), 1.17 (3H, d,
ꢄ
ꢀ1
ꢄ
13
3
1
1.8, 33.1, 73.6 , 73.8, 170.8; IR ꢂmax cm : 3451, 2933, 2860, 1736,
J ¼ 6:5 Hz), 1.25–1.5 (8H, m), 3.31 (1H, m), 3.57 (1H, m); C-NMR
þ
ꢄ
ꢄ
ꢀ1
373, 1244, 1053; GC-MS m=z: tR 23.17 min, 128 (3%, [M-60] ), 61
ꢁ: 14.1, 19.5 , 22.6, 25.3, 31.9, 33.3, 70.9 , 76.3; IR ꢂmax cm : 3388,
2931, 2860, 1460, 1379, 1065; GC-MS m=z: tR 21.79 min, 101 (22%,
þ
(
100%) [D4-5: tR 23.08 min, 132 (3%, [M-60] ), 61 (100%)]. erythro-
1
ꢄ
þ
Isomer of 5: H-NMR ꢁ: 0.89 (3H, t, J ¼ 7 Hz), 1.21 (3H, d,
J ¼ 6:5 Hz), 1.25–1.5 (8H, m), 2.07 (3H, s), 3.69 [1H, m (dd, J ¼ 6,
[M-45] ), 83 (93%), 55 (100%) [D4-2: tR 21.72 min, 101 (30%,
þ
1
[M-49] ), 83 (100%), 55 (92%)]. erythro-Isomer of 2: H-NMR ꢁ: 0.90
ꢄ
ꢄ
13
6
1
Hz, in D4-compound)], 4.88 (1H, dq, J ¼ 3, 6.5 Hz); C-NMR ꢁ:
(3H, t, J ¼ 7 Hz), 1.13 (3H, d, J ¼ 6:5 Hz), 1.25–1.4 (7H, m), 1.51
ꢄ
ꢄ
ꢄ
13
ꢄ
3.6 , 14.0, 21.34, 22.6, 25.5, 31.8, 32.3, 73.3 , 73.9, 170.6; GC-MS
þ
(1H, m), 3.57 (1H, m), 3.77 (1H, m); C-NMR ꢁ: 14.1, 16.5 , 22.6,
ꢄ
m=z: tR 23.34 min, 128 (3%, [M-60] ), 61 (100%) [D4-compound: tR
25.8, 31.8, 31.9, 70.5 , 75.0; GC-MS m=z: tR 22.63 min, 101 (24%, [M-
þ
1
þ
2
3.24 min, 132 (3%, [M-60] ), 61 (100%)]. 6: H-NMR ꢁ: 0.88 (3H, t,
ꢄ
45] ), 83 (90%), 55 (100%) [D4-compound: tR 22.57 min, 101 (30%,
þ
þ
J ¼ 7 Hz), 1.17 (3H, d, J ¼ 6:5 Hz), 1.25–1.5 (8H, m), 2.10 (3H, s),
[M-49] ), 83 (100%), 55 (92%)]. HR-MS m=z ([M-43] ) of diacetate

2256
R. KIYOTA et al.
of 2: calcd. for C10H19O3, 187.1334; found, 187.1338. HR-MS m=z
3) Mori K and Otsuka T, Tetrahedron, 41, 553–556 (1985).
4) Bel-Rhlid R, Fauve A, and Veschambre H, J. Org. Chem., 54,
3221–3223 (1989).
þ
([M-43] ) of diacetate of D4-2: calcd. for C10H15D4O3, 191.1581;
found, 191.1513. The resolution of racemic 2 and D4-2 by chiral HPLC
equipped with an AS-H column gave (2S,3S)-2, D4-(2S,3S)-2, and their
5) Hall DR, Cork A, Phythian SJ, Chittamuru S, Jayarama BK,
Venkatesha MG, Sreedharan K, Vinod Kumar PK, Seetharama
HG, and Naidu R, J. Chem. Ecol., 32, 195–219 (2006).
6) Leal WS, Shi X, Nakamuta K, Ono M, and Meinwald J, Proc.
Natl. Acad. Sci. USA, 92, 1038–1042 (1995).
23
enantiomers. ½ꢀꢅD : (2S,3S)-2, ꢀ18:0 ꢃ (c ¼ 0:31, CHCl3); (2R,3R)-2,
ꢃ
ꢃ
1
8.7 (c ¼ 0:32, CHCl3); D4-(2S,3S)-2, ꢀ32:4 (c ¼ 0:28, CHCl3);
ꢃ
D4-(2R,3R)-2, 25.7 (c ¼ 0:20, CHCl3).
7
)
Schr o¨ der F, Fettk o¨ ther R, Noldt U, Dettner K, K o¨ nig WA, and
Francke W, Liebigs Ann. Chem., 1211–1218 (1994).
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2