Improved synthesis of three methyl-branched pheromone components produced by the female lichen moth

Article abstract of DOI:10.1271/bbb.90639

Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produce a novel sex pheromone composed of three methyl-branched ketones: 6-methyl-2-octade-canone (I), 14-methyl-2-octadecanone (II), and 6,14-dimethyl-2-octadecanone (III). Their structures were confirmed by syntheses accomplished by a different route for each component. In order to obtain a sufficient amount of the synthetic pheromone, we developed new routes via methyl-branched 1-alkenes: 6-methyl-l-octa-decene (1), 14-methyl-l-octadecene (2), and 6,14-di-methyl-1-octadecene (3). Compound 1 was synthesized by coupling between a C₁₀-chain bromide and a 3-methyl-branched C₈ unit (A) prepared from 3-methyl-1,5-pentanediol, 2, by coupling between a C ₁₁-chain bromide and a 3-methyl-branched C₇ unit (B) prepared from 2-hexanone, and 3, by connecting A and B, using propargyl alcohol as a C₃ linchpin. The use of 3-chloro-1-propanol and tert-butyl acetoacetate as the linchpin was also examined to connect the two synthetic blocks in the synthesis of 3. Components I-III were obtained by Wacker oxidation of the corresponding 1-alkenes 1-3 in good yields.

Full text of DOI:10.1271/bbb.90639

Biosci. Biotechnol. Biochem., 74 (1), 119–124, 2010
Improved Synthesis of Three Methyl-Branched Pheromone Components
Produced by the Female Lichen Moth
y
1;
Tomonori TAGURI,1 Rei YAMAKAWA,1 Yasushi ADACHI,1 Kenji MORI,2 and Tetsu ANDO
1Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology,
Koganei, Tokyo 184-8588, Japan
2Photosensitive Materials Research Center, Toyo Gosei Co., Ltd., 4-2-1 Wakahagi, Inba-mura, Inba-gun,
Chiba 270-1609, Japan
Received August 31, 2009; Accepted October 5, 2009; Online Publication, January 7, 2010
[doi:10.1271/bbb.90639]
Female moths of Lyclene dharma dharma (Arctiidae,
Lithosiinae) produce a novel sex pheromone composed
of three methyl-branched ketones: 6-methyl-2-octade-
canone (I), 14-methyl-2-octadecanone (II), and 6,14-
dimethyl-2-octadecanone (III). Their structures were
confirmed by syntheses accomplished by a different
route for each component. In order to obtain a sufficient
amount of the synthetic pheromone, we developed new
routes via methyl-branched 1-alkenes: 6-methyl-1-octa-
decene (1), 14-methyl-1-octadecene (2), and 6,14-di-
methyl-1-octadecene (3). Compound 1 was synthesized
by coupling between a C10-chain bromide and a 3-
methyl-branched C8 unit (A) prepared from 3-methyl-
1,5-pentanediol, 2, by coupling between a C11-chain
bromide and a 3-methyl-branched C7 unit (B) prepared
from 2-hexanone, and 3, by connecting A and B, using
propargyl alcohol as a C3 linchpin. The use of 3-chloro-
1-propanol and tert-butyl acetoacetate as the linchpin
was also examined to connect the two synthetic blocks in
the synthesis of 3. Components I–III were obtained by
Wacker oxidation of the corresponding 1-alkenes 1–3 in
good yields.
corresponding natural component.4,5) Furthermore, lures
baited with the optically inactive synthetic ketones
successfully attracted many L. d. dharma males in the
field.5)
L. d. dharma belongs to Lithosiinae in the family of
Arctiidae and is the first species whose sex pheromone
has been revealed among the species in this subfamily.
The Lithosiinae species, called lichen moths, are
commonly found throughout the world, and about 80
species inhabit Japan. The larvae mainly feed on the
lichen in forests and contribute to the ecosystem of the
forest. While information on the ecological aspects of
the Lithosiinae species is very limited, the pheromone,
which can be easily synthesized with achiral materials,
is utilized as a good monitoring tool for the adults. In
our previous study, three components were separately
synthesized by routes that started from diols of different
chain length and involved no common synthetic units.4,5)
To obtain a sufficient amount of the synthetic pher-
omone, we investigated methods for increasing the
yields of the three components. This report presents new
synthetic routes for I–III via Wacker oxidation of the
terminal alkenes which were constructed with common
synthetic units.
Key words: Lepidoptera; female sex pheromone; methyl-
branched 2-ketone; methyl-branched 1-
alkene; Wacker oxidation
Results and Discussion
Lepidopteran sex pheromones have been identified
from adult females of more than 600 species. In addition
to Type I and II pheromones with a straight chain, there
are a considerable number of miscellaneous chemi-
cals,1–3) and we have recently identified novel methyl-
branched ketones from Lyclene dharma dharma. The
L. d. dharma females, which were caught on the
Iriomote Islands, produced 6-methyl-2-octadecanone
(I), 14-methyl-2-octadecanone (II), and 6,14-dimethyl-
2-octadecanone (III). The structures were estimated
by GC-MS analyses of the pheromone gland extracts
before and after Wollf-Kishner reduction.4) Although the
absolute configurations of their chiral centers could not
be determined because of the difficulty collecting a
sufficient amount of the pheromone extract, the planar
structures of I–III were confirmed by the synthesis
regardless of their stereochemistry. The mass spectrum
of each synthetic ketone coincided well with that of the
Wacker oxidation6) might enable I–III to be directly
synthesized from the corresponding 1-alkenes: 6-methyl-
1-octadecene (1), 14-methyl-1-octadecene (2), and 6,14-
dimethyl-1-octadecene (3). Since both 1 and 2 bear a
structure common to 3, we made a synthetic plan for 1–3
which involved mutual synthetic blocks, as shown in
Fig. 1. If 1 and 2 could be prepared from methyl-
branched C8 and C7 units (A and B), 3 could be
synthesized by coupling A and B, using a C3-chain
compound as the linchpin.
Scheme I in Fig. 2 summarizes the synthesis of the
key building block (A1; A, X ¼ OTs) and its conversion
to I. 3-Methyl-1,5-pentanediol was introduced to sila-
nyloxy tosylate (4) by treating tosyl chloride (TsCl) after
mono sililating by tert-butyldimethylsilyl chloride
(TBDMSCl). Tosylate 4 was coupled with allylmagne-
sium bromide by employing the Schlosser’s copper-
catalyzed Grignard reaction,7) and its TBDMS group
y
To whom correspondence should be addressed. Tel/Fax: +81-42-388-7278; E-mail: antetsu@cc.tuat.ac.jp

120
T. TAGURI et al.
O
+
C10
X
A
+
1
2
Comp. I
O
C11
A
Y
B
+
Comp. II
Comp. III
O
B
C3
+
3
Fig. 1. Synthetic Strategy for Three Methyl-Branched Pheromone Components (I–III) Using 3-Methyl-Branched C8 and C7 Units (A and B) as Key
Synthetic Blocks.
X ¼ OTs (A1) and X ¼ I (A2) in A; Y ¼ OTs (B1), Y ¼ I (B2), and Y ¼ MgBr (B3) in B
Scheme I
c, d
b
a, b
A1
HO
OH
TBDMSO
OTs
HO
82%
75%
93%
4
5
e
f
1
2
Comp. I
Comp. II
98%
70%
Scheme II
O
g
h, i
b
CO2Et
B1
OH
93%
95%
92%
7
6
j
f
94%
76%
Scheme III
k
h, d
B2
l,
OH
OCH2Ph
OCH2Ph
Br
86%
92%
75%
8
9
A
n,
f
m
1
OH
Comp. III
3
92%
46%
70%
10
11
Fig. 2. Synthetic Routes to 6-Methyl-2-octadecanone (Component I, Scheme I), 14-Methyl-2-octadecanone (Component II, Scheme II), and 6,14-
Dimethyl-2-octadecanone (Component III, Scheme III).
a, 1) BuLi, THF, 2) TBDMSCl; b, TsCl, DMAP, pyridine; c, CH2=CHCH2MgBr, Li2CuCl4, Et2O; d, TBAF, THF; e, CH3(CH2)9MgBr,
Li2CuCl4, THF; f, O2, PdCl2, CuCl, DMF-H2O; g, (EtO)2POCH2CO2Et, NaH, THF; h, H2, Pd-C, MeOH; i, LiAlH4, Et2O; j, CH2=
CH(CH2)9MgBr, Li2CuCl4, THF; k, PhCH2Br, NaH, NaI, DMF; l, BuLi, THF-HMPA; m, HBr, H2SO4; n, 1) Mg, Et2O, 2) Li2CuCl4, THF
was removed to yield 3-methyl-7-octen-1-ol (5) which
was converted into tosylate A1 by TsCl. This unit (A1)
was coupled with n-decylmagnesium bromide to yield 1-
alkene 1, and 6-methyl-2-ketone I was obtained by
Wacker oxidation of 1. Scheme II in Fig. 2 is a
summary of the synthesis of another key block (B1; B,
Y ¼ OTs) and its conversion to II. 2-Hexanone was
coupled with the anion prepared from triethyl phospho-
noacetate8) to yield a mixture of (Z)- and (E)-ethyl
3-methyl-2-heptenoate (6), which was converted into
3-methyl-1-heptanol (7) by catalytic hydrogenation and
LiAlH4 reduction. Alcohol 7 was treated with TsCl
to build up tosylate B1, which was coupled with
10-undecenylmagnesium bromide to construct another
1-alkene 2. 14-Methyl-2-ketone II was obtained by
Wacker oxidation of 2.
Scheme III in Fig. 2 shows the synthesis of III via
dimethyl-1-alkene 3 which utilized propargyl alcohol
as a linchpin. The alcohol was converted into benzyl
ether (8) and coupled with an iodide9) (B2; B, Y ¼ I),
which had been prepared from 7, to yield a compound
with a methyl-branched C10-chain (9). Hydrogenation of
the triple bond and deprotection of the benzyl ether of 9
gave 6-methyl-1-octanol (10). Alcohol 10 was converted
to a Grignard reagent via bromide (11) and coupled with
A1 to yield 3 under the same copper-catalyzed condition
as that for the syntheses of 1 and 2.7) 6,14-Dimethyl-2-
ketone III was obtained by Wacker oxidation of 3.
Dimethyl-1-alkene 3 was also synthesized with the
other C3 linchpins as shown in Fig. 3. The tosylate of
3-chloro-1-propanol (12) was coupled with a Grignard
reagent (B3; B, Y ¼ MgBr) to yield 1-chloro-6-methyl-
decane (13). Chloride 13 was converted to a Grignard
reagent and coupled with A1 to yield 3 (Scheme IV). We
also attempted to use tert-butyl acetoacetate as the C3
linchpin (Scheme V). The dianion of tert-butyl aceto-
acetate, which had been generated by treating with NaH
and butyllithium (BuLi),10) was coupled with B2 to yield
a ketoester (14). This step was more smoothly accom-
plished by the iodide than by the tosylate B1. As a
second alkylation, the activated enolate of 14, which had
been generated by treating with potassium tert-butoxide,
was coupled with another iodide (A2; A, X ¼ I). Since it
was not easy to separate the required ketoester with a
long chain (15), the reaction mixture was used in further
steps involving dealkoxycarbonylation under an acidic
condition and Wollf-Kishner reduction after partial
purification. While no intermediates other than 14 in
Scheme V were isolated and characterized, the GC-MS
analysis confirmed the formation of 3, and a pure sample
was obtained after the usual silica gel column chroma-
tography. The insufficient yield might be improved by

Synthesis of the Lithosiinae Sex Pheromone
121
Scheme IV
HO
b, B3
c, A1
a
Cl
TsO
Cl
Cl
3
95%
88%
20%
12
13
Scheme V
O
O
d, B2
O
f
e, A2
3
CO2t-Bu
CO2t-Bu
70%
39% from 14
CO2t-Bu
15
14
Fig. 3. Synthetic Routes to 6,14-Dimethyl-1-octadecene (3) Starting from 3-Chloropropan-1-ol (Scheme IV) and tert-Butyl Acetoacetate
(Scheme V).
a, TsCl, DMAP, C5H5N; b, Li2CuCl4, THF; c, Mg, MeMgBr, THF, Li2CuCl4; d, NaH, THF-HMPA, BuLi; e, t-BuOK, t-BuOH, ꢀ;
f, 1) TsOH, ꢀ, 2) NH2NH2, KOH, DEG, ꢀ
Table 1. 13C-NMR Assignments for the Synthetic 1-Alkenes 1–3 and
2-Alkanone IIIa
examining the conditions for each step in detail and
by applying other starting esters such as ethyl aceto-
acetate. The corresponding alkylated ethyl acetoacetate
might be easily dealkoxycarbonylated under a neutral
condition.11)
Chemical shift (ꢀ ppm)
Position
1
2
3
III
1
2
114.1
139.3
34.2
114.1
139.3
33.9
114.1
139.3
34.2
29.9
209.4
44.2
The improved synthetic routes shown in Fig. 2 enable
three 2-ketones I–III to be synthesized in 18–58% total
yields, while our previous syntheses achieved less than
10% total yields.4,5) The GC-MS data for new synthetic
I–III coincided well with those of the corresponding
natural pheromone components, and the NMR data were
the same as those of the compounds previously
synthesized.4,5,12) 14-Methyl-1-octadecene 2, our syn-
thetic intermediate for II, is a pheromone component
of the peach leafminer moth, Lyonetia clerkella L.
(Lyonetiidae).13) While several reports have described
3
4
26.4
36.6
ꢂ30
26.4
36.6
21.4
36.5
5
ꢂ30
ꢂ30
ꢂ30
ꢂ30
ꢂ30
6
32.67
37.05
27.09
32.68
37.06
27.10c
ꢂ30g
27.12c
36.81d
32.75
37.13d
ꢂ30g
23.1
32.65
36.90
27.05e
ꢂ30h
27.11e
36.79f
32.74
37.11f
ꢂ30h
23.1
7
8
9–11
12
13
14
15
16
17
18
6Me
14Me
ꢂ30
ꢂ30
ꢂ30
ꢂ30
ꢂ30
27.12
36.82b
32.76
37.13b
1
its synthesis and H-NMR data,13–17) assignment of the
32.0
ꢂ30
13C-NMR signals has not been reported. We assigned
the 13C signals of 1-alkenes 1–3 by comparing them
with those of 2-ketones I–III previously analyzed5) and
confirmed the results with the use of two-dimensional
experiments (Table 1). Signal separation in the 13C-
22.7
14.1
19.69
—
23.1
14.2
—
14.2
19.70
19.74
14.2
19.55
19.73
19.74
a6-Methyl-1-octadecene (1), 14-methyl-1-octadecene (2), 6,14-dimethyl-1-
octadecene (3), and 6,14-dimethyl-2-octadecanone (III). NMR data for III
have been reported in a previous paper.5)
1
NMR spectra was markedly better than that in the H-
NMR spectra, indicating the 13C-NMR analysis as one
of the most reliable tools to confirm the structure of a
synthetic pheromone with a methyl-branched skeleton.
Studies on pheromones with the structure of a
1-alkene or 2-ketone are still very limited.1–3) Further
investigation of the communication systems of many
lepidopteran species, particularly in the families of
Arctiidae and Lyonetiidae, make it necessary to system-
atically synthesize many authentic standards with a
methyl-branched structure. Synthetic blocks A and B
can be respectively utilized for 6-methyl and !5-methyl
compounds for this purpose. In the case of the
L. d. dharma pheromone, optically active isomers of
each component have been synthesized by olefin cross-
metathesis, utilizing blocks with a C10-chain.12) We are
going to prepare optically active A and B to establish a
different route.
b{f Chemical shift values may be reversed.
g29.4, 29.8, 30.05, and 30.07.
h29.4, 29.8, 30.02, and 30.05.
HP5973 mass spectrometer (Hewlett-Packard) equipped with a split/
splitless injector and a DB-23 column (0:25 mm ID ꢀ 30 m, 0.25 mm
film; J & W Scientific, Folsom, CA, USA). The column temperature
program was 50 ꢁC for 2 min, 10 ꢁC/min to 160 ꢁC, and 4 ꢁC/min to
220 ꢁC. The carrier gas was He. IR spectra were recorded as a thin film
(neat liquid) with an FT/IR-350 instrument (Jasco, Tokyo, Japan).
5-(tert-Butyldimethylsilyl)oxy-3-methylpentyl tosylate (4). BuLi (a
1.65 M hexane solution, 30 ml) was added dropwise to a solution of 3-
methyl-1,5-pentanediol (5.9 g, 50 mmol) in dry THF (60 ml) in a three-
necked flask while stirring under an Ar atmosphere. After stirring at
room temperature (rt) for 10 min, TBDMSCl (7.5 g, 50 mmol) dissolved
in dry THF (10 ml) was added via a syringe. The mixture was stirred for
45 min at rt, poured into a saturated aqueous solution of NH4Cl, and
extracted with Et2O (3 ꢀ 100 ml). The resulting organic layer was
successively washed with H2O, a NaHCO3 solution and brine, dried
over Na2SO4, and concentrated in vacuo. The crude product was
chromatographed over SiO2 (200 g), and elution with hexane/EtOAc
(from 10:1 to 5:1) gave 5-(tert-butyldimethylsilyl)oxy-3-methyl-1-
pentanol (9.7 g, 42 mmol, 84%). This alcohol was added to a mixture of
dry pyridine (30 ml), TsCl (8.8 g, 46 mmol), and 4-(dimethylamino)-
pyridine (DMAP, 100 mg) which were stirred in a three-necked flask
cooled in an ice bath under Ar. The crude product was stirred for 2 h in
the bath, poured into an HCl solution (1.0 M, 250 ml), and extracted
Experimental
Instruments. 1H- 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. 1H-1H COSY, HMQC, and HMBC spectra were also
measured with the same spectrometer, using the usual pulse sequences
and parameters. GC-MS was conducted in the EI mode (70 eV) with an

122
T. TAGURI et al.
with EtOAc (3 ꢀ 100 ml). The resulting organic layer was successively
washed with H2O, a NaHCO3 solution and brine, dried over Na2SO4,
and concentrated in vacuo. The residual materials were chromato-
graphed over SiO2 (200 g), elution with hexane/EtOAc (10:1) gave
tosylate 4 (16 g, 41 mmol, 98%). 1H-NMR ꢀ: 0.02 (6H, s, Si(CH3)2),
0.83 (3H, d, J ¼ 6:5 Hz, CH3CH), 0.87 (9H, s, SiC(CH3)3), 1.32 (1H,
m), 1.47 (2H, m), 1.69 (2H, m), 2.45 (3H, s, CH3Ph), 3.59 (2H, m,
TBDMSOCH2), 4.07 (2H, m, TsOCH2), 7.34 (2H, d, J ¼ 8:5 Hz), 7.79
(2H, d, J ¼ 8:5 Hz). 13C-NMR ꢀ: ꢃ5:4 (ꢀ2), 18.3, 19.2, 21.6, 25.9
(ꢀ3), 26.2, 35.7, 39.4, 60.9, 68.9, 127.9 (ꢀ2), 129.8 (ꢀ2), 133.2,
144.6. IR ꢁmax cmꢃ1: 2929, 1604, 1475, 1363, 1178, 1097, 943, 837,
775, 663, 555.
J ¼ 6:5 Hz, CH3CH), 0.88 (3H, t, J ¼ 6:5 Hz, CH3CH2), ꢂ1:1 (2H,
m), ꢂ1:25 (22H, m), ꢂ1:35 (3H, m), 2.02 (2H, dt, J ¼ 7, 7 Hz,
CH2CH=C), 4.93 (1H, d, J ¼ 10:5 Hz, CH=CHH), 4.99 (1H, d,
J ¼ 17 Hz, CH=CHH), 5.82 (1H, ddt, J ¼ 17, 10.5, 6.5 Hz,
CH=CH2). IR ꢁmax cmꢃ1: 3078, 2924, 2846, 1641, 1464, 993, 908.
GC-MS: tR 12.74 min; m=z 266 (Mþ, 1%), 97 (100%), 57 (90%).
Ethyl 3-methyl-2-heptenoate (6). Triethyl phosphonoacetate (18.9 g,
72 mmol) dissolved in dry THF (40 ml) was treated with NaH (60%,
2.9 g, 72 mmol) while stirring at rt under Ar. The reaction mixture was
stirred for 20 min at rt, and EtOH (4.0 ml) was then added to quench
the remaining NaH. Next, 2-hexanone (6.0 g, 60 mmol) was added
dropwise and the mixture stirred for 1 h at rt and for an additional
30 min under reflux. The mixture was then cooled to rt, poured into a
saturated aqueous solution of NH4Cl (100 ml), and extracted with Et2O
(3 ꢀ 100 ml). After the usual work-up, the crude product was
chromatographed over SiO2 (300 g) with eluention by hexane and
hexane/EtOAc (10:1) to give a 1:1 mixture of (Z)-2-heptenoate and its
(E)-isomer (6; 9.5 g, 56 mmol, 93%). 1H-NMR (Z)-isomer ꢀ: 0.92 (3H,
t, J ¼ 7 Hz, CH3CH2CH2), 1.27 (3H, t, J ¼ 7 Hz, CH3CH2O), ꢂ1:4
(4H, m), 1.88 (3H, d, J ¼ 1:5 Hz, CH3C=C), 2.62 (2H, t, J ¼ 7:5 Hz,
CH2C=C), 4.13 (2H, q, J ¼ 7 Hz, CH3CH2O), 5.65 (1H, m, CH=C);
(E)-isomer ꢀ: 0.91 (3H, t, J ¼ 7 Hz, CH3CH2CH2), 1.28 (3H, t,
J ¼ 7 Hz, CH3CH2O), ꢂ1:4 (4H, m), 2.13 (2H, m, CH2C=C), 2.15
(3H, d, J ¼ 1:5 Hz, CH3C=C), 4.14 (2H, q, J ¼ 7 Hz, CH3CH2O),
5.66 (1H, m, CH=C). 13C-NMR ꢀ: 13.9, 14.0, 14.3, 14.4, 18.7, 22.3,
22.9, 25.2, 29.6, 30.4, 33.2, 40.7, 59.40, 59.44, 115.4, 116.0, 160.4,
160.8, 166.4, 166.9. IR ꢁmax cmꢃ1: 2908, 1739, 1649, 1461, 1367,
1149, 1039, 731. GC-MS: tR 8.20 min; m=z 170 (Mþ, 40%), 141
(46%), 125 (59%), 55 (100%).
3-Methyl-7-octen-1-ol (5). Tosylate 4 (15.5 g, 40 mmol) dissolved
in dry Et2O (60 ml) was treated with Li2CuCl4 (a 0.1 M THF solution,
1.0 ml) and allylmagnesium bromide (a 1.0 M Et2O solution, 44 ml)
while stirring at 0 ꢁC under Ar. The mixture was stirred at 0 ꢁC for 8 h
and poured into an H2SO4 solution (2.0 M, 200 ml), and the product
was extracted with Et2O (3 ꢀ 100 ml). After the usual work-up, the
crude product was chromatographed over SiO2 (200 g) with an eluent
of hexane/EtOAc (10:1) to give the TBDMS ether of 5 (8.5 g,
33 mmol, 83%). Next, to remove the protective group, the ether
dissolved in dry THF (10 ml) was treated with tetrabutylammonium
fluoride (TBAF, a 1.0 M THF solution, 40 ml) under Ar. The mixture
was stirred at rt for 3 h, poured into a saturated aqueous solution of
NH4Cl (100 ml), and extracted with Et2O (3 ꢀ 100 ml). After the usual
work-up, the crude product was chromatographed over SiO2 (200 g)
with an eluent of hexane/EtOAc (from 10:1 to 5:1) to give 5 (4.3 g,
30 mmol, 91%). 1H-NMR ꢀ: 0.90 (3H, d, J ¼ 6:5 Hz, CH3CH), ꢂ1:3
(4H, m), ꢂ1:6 (2H, m), 1.87 (1H, m), 2.04 (2H, dt, J ¼ 7, 7 Hz,
CH2CH=C), 3.68 (2H, m, CH2OH), 4.94 (1H, d, J ¼ 10:5 Hz,
CH=CHH), 5.00 (1H, d, J ¼ 17 Hz, CH=CHH), 5.81 (1H, ddt,
J ¼ 17, 10.5, 6.5 Hz, CH=CH2). 13C-NMR ꢀ: 19.6, 26.3, 29.4, 34.0,
36.5, 39.9, 61.2, 114.3, 139.1. IR ꢁmax cmꢃ1: 3365, 3078, 2929, 1641,
1460, 1057, 999, 910. GC-MS (relative intensity): tR 9.97 min; m=z 124
(½M ꢃ 18ꢄþ, 1%), 109 (11%), 81 (55%), 55 (100%).
3-Methyl-1-heptanol (7). A mixture of the heptenoate 6 (9.4 g,
55 mmol), Pd-C (10%, 250 mg), and MeOH (100 ml) was stirred under
H2 at rt for 1.5 h. After filtering off the catalyst, the solvent was
evaporated. The produced heptanoate dissolved in dry THF (20 ml)
was added dropwise to LiAlH4 (2.1 g, 55 mmol) suspended in dry THF
(30 ml) cooled in an ice bath. After stirring at rt for 1 h, an HCl solution
(1.0 M, 150 ml) was added dropwise to the reaction mixture, and the
crude product was extracted with Et2O (3 ꢀ 100 ml). After the usual
work-up, the product was chromatographed over SiO2 (200 g) with an
elution by hexane and hexane/EtOAc (from 10:1 to 2:1) to give 7
(6.8 g, 52 mmol, 95%). 1H-NMR ꢀ: 0.89 (3H, d, J ¼ 6:5 Hz, CH3CH),
0.89 (3H, t, J ¼ 6:5 Hz, CH3CH2), ꢂ1:3 (7H, m), ꢂ1:6 (2H, m), 3.69
(2H, m, CH2OH). 13C-NMR ꢀ: 14.1, 19.7, 23.0, 29.2, 29.5, 36.8, 40.0,
61.2. IR ꢁmax cmꢃ1: 3334, 2924, 1460, 1379, 1057. GC-MS: tR
8.23 min; m=z 112 (½M ꢃ 18ꢄþ, 2%), 97 (4%), 84 (67%), 55 (100%).
3-Methyl-7-octenyl tosylate (A1). In a similar manner to that for the
preparation of 4, alcohol 5 (4.3 g, 30 mmol) was tosylated with TsCl
(6.9 g, 36 mmol) and DMAP (200 mg). The crude product was
chromatographed over SiO2 (150 g) with an eluent of hexane/EtOAc
(10:1) to give A1 (8.4 g, 28 mmol, 93%). 1H-NMR ꢀ: 0.81 (3H, d,
J ¼ 6:5 Hz, CH3CH), 1.0–1.6 (6H, m), 1.66 (1H, m), 1.97 (2H, dt,
J ¼ 7, 7 Hz, CH2CH=C), 2.45 (3H, s, CH3Ph), 4.05 (2H, m, TsOCH2),
4.92 (1H, d, J ¼ 10:5 Hz, CH=CHH), 4.95 (1H, d, J ¼ 17 Hz,
CH=CHH), 5.76 (1H, ddt, J ¼ 17, 10.5, 6.5 Hz, CH=CH2), 7.34
(2H, d, J ¼ 8:5 Hz), 7.78 (2H, d, J ¼ 8:5 Hz). 13C-NMR ꢀ: 19.1, 21.6,
26.0, 29.0, 33.8, 35.6, 36.0, 69.0, 114.4, 127.8 (ꢀ2), 129.8 (ꢀ2), 133.1,
138.7, 144.6. IR ꢁmax cmꢃ1: 3074, 2927, 1639, 1599, 1460, 1361, 1176,
1097, 945, 891, 816, 665, 555.
3-Methylheptyl tosylate (B1). In a similar manner to that for the
preparation of 4, alcohol 7 (6.5 g, 50 mmol) was tosylated with TsCl
(11.4 g, 60 mmol) and DMAP (300 mg). The product was chromato-
graphed over SiO2 (200 g) with elution by hexane/EtOAc (10:1) to
give B1 (8.4 g, 46 mmol, 92%). 1H-NMR ꢀ: 0.80 (3H, d, J ¼ 6:5 Hz,
CH3CH), 0.86 (3H, t, J ¼ 6:5 Hz, CH3CH2), 1.0–1.3 (6H, m), ꢂ1:4
(1H, m), ꢂ1:5 (1H, m), 1.65 (1H, m), 2.45 (3H, s, CH3Ph), 4.06 (2H,
m, TsOCH2), 7.35 (2H, d, J ¼ 8:5 Hz), 7.79 (2H, d, J ¼ 8:5 Hz). 13C-
NMR ꢀ: 14.1, 19.2, 21.6, 22.8, 29.0, 29.1, 35.7, 36.3, 69.1, 127.9 (ꢀ2),
129.8 (ꢀ2), 133.2, 144.6. IR ꢁmax cmꢃ1: 2927, 1599, 1466, 1362, 1176,
945, 887, 816, 665, 555.
8-Iodo-6-methyl-1-octene (A2). NaI (4.5 g, 30 mmol) was added to a
solution of tosylate A1 (5.7 g, 20 mmol) in dimethylformamide (DMF,
25 ml) at rt, and the mixture was stirred at 100 ꢁC for 2 h. After cooling
to rt, the mixture was poured into water (400 ml) and extracted with
hexane (3 ꢀ 100 ml). The crude product was chromatographed over
SiO2 (100 g) after the usual work-up. Elution with hexane gave A2
(4.5 g, 18 mmol, 90%). 1H-NMR ꢀ: 0.88 (3H, d, J ¼ 6:5 Hz, CH3CH),
ꢂ1:3 (4H, m), ꢂ1:55 (1H, m), 1.65 (1H, m), 1.87 (1H, m), 2.04 (2H,
dt, J ¼ 7, 7 Hz, CH2CH=C), 3.17 (1H, ddd, J ¼ 9:5, 8, 8 Hz, CHHI),
3.25 (1H, ddd, J ¼ 9:5, 9.5, 5.5 Hz, CHHI), 4.95 (1H, d, J ¼ 10:5 Hz,
CH=CHH), 5.00 (1H, d, J ¼ 17 Hz, CH=CHH), 5.81 (1H, ddt,
J ¼ 17, 10.5, 6.5 Hz, CH=CH2). 13C-NMR ꢀ: 5.2, 18.7, 26.1, 33.7,
33.9, 35.7, 40.9, 114.4, 138.9. IR ꢁmax cmꢃ1: 3076, 2927, 1639, 1460,
1178, 995, 910, 606. GC-MS: tR 9.80 min; m=z 252 (Mþ, 1%), 155
(6%), 97 (13%), 55 (100%).
1-Iodo-3-methylheptane (B2). In a similar manner to that for the
iodination of A1, tosylate B1 (5.7 g, 20 mmol) was converted to B2
(4.3 g, 18 mmol, 90%). 1H-NMR ꢀ: 0.87 (3H, d, J ¼ 6:5 Hz, CH3CH),
0.89 (3H, t, J ¼ 6:5 Hz, CH3CH2), 1.1–1.35 (6H, m), ꢂ1:55 (1H, m),
1.64 (1H, m, CHHCH2I), 1.87 (1H, m, CHHCH2I), 3.17 (1H, ddd,
J ¼ 9:5, 8, 8 Hz, CHHI), 3.25 (1H, ddd, J ¼ 9:5, 9.5, 5.5 Hz, CHHI).
13C-NMR ꢀ: 5.3, 14.1, 18.8, 22.9, 29.0, 33.9, 35.9, 41.0. IR ꢁmax cmꢃ1
:
2925, 1464, 1379, 1214, 1178, 606. GC-MS: tR 7.96 min; m=z 240
(Mþ, 2%), 155 (7%), 127 (3%), 113 (20%), 57 (100%).
6-Methyl-1-octadecene (1). In a similar manner to that for the
alkylation of 4, tosylate A1 (3.0 g, 10 mmol) was coupled with
decylmagnesium bromide (a 1.0 M Et2O solution, 14 ml) by using
Li2CuCl4 (a 0.1 M THF solution, 1.0 ml) as a catalyst. The crude
product was chromatographed over SiO2 (150 g) with an eluent of
hexane to give 1 (2.6 g, 9.8 mmol, 98%). 1H-NMR ꢀ: 0.85 (3H, d,
14-Methyl-1-octadecene (2). To dry THF (30 ml) containing Mg
turnings (0.97 g, 40 mmol), 11-bromo-1-undecene (4.7 g, 20 mmol) in
dry THF (4 ml) was added while stirring at 0 ꢁC under Ar. After stirring
at 0 ꢁC for 1 h, the mixture was warmed to rt. The produced Grignard

Synthesis of the Lithosiinae Sex Pheromone
123
reagent was taken up in a syringe and added to a solution of B1 (4.3 g,
18 mmol) and Li2CuCl4 (a 0.1 M THF solution, 1.0 ml) in dry THF
(20 ml) at ꢃ78 ꢁC under Ar. The mixture was gradually warmed to rt.
Stirring was continued for 14 h, the mixture was poured into a cool
H2SO4 solution (1.0 M, 150 ml), and the product was extracted with
hexane (3 ꢀ 100 ml). After the usual work-up, the extract was
chromatographed over SiO2 (90 g) impregnated with AgNO3 (10 g)
with elution by hexane and benzene to give 2 (4.5 g, 17 mmol, 94%).
1H-NMR ꢀ: 0.84 (3H, d, J ¼ 6:5 Hz, CH3CH), 0.89 (3H, t, J ¼ 6:5 Hz,
CH3CH2), ꢂ1:1 (2H, m), ꢂ1:25 (22H, m), ꢂ1:35 (3H, m), 2.04 (2H,
dt, J ¼ 7, 7 Hz, CH2CH=C), 4.92 (1H, d, J ¼ 10:5 Hz, CH=CHH),
4.99 (1H, d, J ¼ 17 Hz, CH=CHH), 5.81 (1H, ddt, J ¼ 17, 10.5,
6.5 Hz, CH=CH2). IR ꢁmax cmꢃ1: 3078, 2924, 2854, 1641, 1466, 991,
908. GC-MS: tR 12.78 min; m=z 266 (Mþ, 1%), 97 (66%), 57 (100%).
1377, 1252, 729, 648, 565. GC-MS: tR 10.40 min; m=z 221 and 219
(½M ꢃ 15ꢄþ, 1%), 151 and 149 (63%), 85 (100%).
6,14-Dimethyl-1-octadecene (3) from bromide 11. In a similar
manner to that for the preparation of 2, a Grignard reagent prepared
from 11 (2.4 g, 10 mmol) and Mg turnings (490 mg, 20 mmol) was
coupled with A1 (1.5 g, 5.0 mmol). The crude product was chromato-
graphed over SiO2 (90 g) impregnated with AgNO3 (10 g) with elution
by hexane/benzene to give 3 (1.3 g, 4.6 mmol, 46% from 11, 92% from
A1). 1H-NMR ꢀ: 0.84 (3H, d, J ¼ 6:5 Hz, CH3CH), 0.85 (3H, d, J ¼
6:5 Hz, CH3CH), 0.88 (3H, t, J ¼ 6:5 Hz, CH3CH2), ꢂ1:1 (4H, m),
ꢂ1:25 (17H, m), ꢂ1:35 (5H, m), 2.02 (2H, dt, J ¼ 7, 7 Hz,
CH2CH=C), 4.93 (1H, d, J ¼ 10:5 Hz, CH=CHH), 4.99 (1H, d, J ¼
17 Hz, CH=CHH), 5.82 (1H, ddt, J ¼ 17, 10.5, 6.5 Hz, CH=CH2).
IR ꢁmax cmꢃ1: 3078, 2925, 2856, 1639, 1460, 993, 908. GC-MS:
tR 13.11 min; m=z 280 (Mþ, 1%), 97 (100%), 57 (94%).
Benzyl ether of propargyl alcohol (8). To a mixture of NaH (60%,
2.0 g, 50 mmol) and NaI (0.75 g, 5 mmol), propargyl alcohol (2.8 g,
50 mmol) in dry DMF (30 ml) was added dropwise while stirring at
0 ꢁC under Ar. After stirring for 30 min, benzyl bromide (8.6 g,
50 mmol) was added dropwise to the mixture while stirring. The
reaction mixture was stirred at 0 ꢁC for 30 min and at rt for 2 h, and
then poured into water (300 ml). The product was extracted with
hexane/EtOAc (1:1, 3 ꢀ 100 ml). After the usual work-up, the extract
was chromatographed over SiO2 (150 g) with elution by hexane/
EtOAc (10:1) to give 8, which was further purified by distillation
(6.3 g, 43 mmol, 86%; boiling point, 190 ꢁC at 80 mm Hg). 1H-NMR ꢀ:
2.45 (1H, t, J ¼ 2:5 Hz, HCꢅC), 4.15 (2H, d, J ¼ 2:5 Hz, CH2CꢅC),
4.59 (2H, s, OCH2Ph), ꢂ7:3 (5H, m). 13C-NMR ꢀ: 57.0, 71.5, 74.7,
79.6, 127.9, 128.1 (ꢀ2), 128.4 (ꢀ2), 137.2. IR ꢁmax cmꢃ1: 3292, 3032,
2856, 2117, 1454, 1356, 1074, 742, 698. GC-MS: tR 11.32 min; m=z
145 (½M ꢃ 1ꢄþ, 11%), 91 (100%).
Wacker oxidation of 1-alkenes 1–3. PdCl2 (89 mg, 0.50 mmol) and
CuCl (0.50 g, 5.0 mmol) were added to a solution of 1 (1.3 g, 5.0 mmol)
in DMF (17.5 ml) and water (2.5 ml). The mixture was stirred at rt, and
then O2 was bubbled into it for 22 h. After the reaction, the mixture
was poured into an HCl solution (1.0 M, 50 ml) and extracted with Et2O
(3 ꢀ 100 ml). After the usual work-up, the crude product was
chromatographed over SiO2 (180 g) with elution by hexane/EtOAc
(from 10:1 to 5:1) to give I (0.98 g, 3.5 mmol, 70%). IR ꢂmax cmꢃ1
:
2924, 2854, 1720, 1464, 1383, 1165. GC-MS: tR 19.13 min; m=z 282
(Mþ, 2%), 264 (½M ꢃ 18ꢄþ, 37%), 58 (100%). In the same manner, 2
(1.0 g, 3.8 mmol) and 3 (0.56 g, 2.0 mmol) were oxidized to II (0.81 g,
2.9 mmol, 76%) and III (0.41 g, 1.4 mmol, 70%), respectively. IR
ꢂ
max cmꢃ1 II: 2924, 2854, 1720, 1466, 1383, 1161; III: 2926, 2854,
1720, 1464, 1377, 1165. GC-MS II: tR 19.32 min; m=z 282 (Mþ, 11%),
264 (½M ꢃ 18ꢄþ, 8%), 58 (100%); III: tR 19.68 min; m=z 296 (Mþ,
2%), 278 (½M ꢃ 18ꢄþ, 32%), 58 (100%).
Benzyl ether of 6-methyl-2-decyn-1-ol (9). To a solution of 1-alkyne
8 (3.8 g, 26 mmol) in dry THF (25 ml), BuLi (a 1.6 M hexane solution,
16 ml) was added dropwise while stirring at ꢃ35 ꢁC under Ar. After
additional stirring for 30 min, B2 (6.2 g, 26 mmol) dissolved in
hexamethylphosphoramide (HMPA, 6 ml) was added to the mixture.
The reaction mixture was stirred at ꢃ35 ꢁC for 30 min and at rt for 1 h,
and then poured into water (300 ml). The product was extracted with
EtOAc (3 ꢀ 100 ml). After the usual work-up, the extract was
chromatographed over SiO2 (200 g) with elution by hexane/EtOAc
(10:1) to give 9 (6.2 g, 24 mmol, 92%). 1H-NMR ꢀ: 0.87 (3H, d,
J ¼ 6:5 Hz, CH3CH), 0.88 (3H, t, J ¼ 6:5 Hz, CH3CH2), ꢂ1:1 (1H,
m), ꢂ1:3 (6H, m), 1.55 (2H, m), 2.24 (2H, m, CꢅCCH2CH2), 4.15
(2H, t, J ¼ 2 Hz, CꢅCCH2O), 4.58 (2H, s, OCH2Ph), ꢂ7:3 (5H, m).
13C-NMR ꢀ: 14.2, 16.5, 19.2, 23.0, 29.1, 31.9, 35.7, 36.3, 57.7, 71.3,
75.6, 87.4, 127.7, 128.1 (ꢀ2), 128.3 (ꢀ2), 137.6. IR ꢁmax cmꢃ1: 3030,
2927, 1454, 1354, 1072, 737, 698. GC-MS: tR 20.19 min; m=z 257
(½M ꢃ 1ꢄþ, 2%), 145 (79%), 91 (100%).
3-Chloro-1-propyl tosylate (12). 3-Chloro-1-propanol (3.8 g,
40 mmol) was tosylated with TsCl (9.2 g, 48 mmol) and DMAP
(200 mg) in a similar manner to that for the preparation of 4. The crude
product was chromatographed over SiO2 (150 g) with elution by
hexane/EtOAc (10:1) to give 12 (9.4 g, 38 mmol, 95%). 1H-NMR ꢀ:
2.09 (2H, tt, J ¼ 6, 6 Hz, CH2CH2Cl), 2.46 (3H, s, CH3Ph), 3.57 (2H,
t, J ¼ 6 Hz, CH2Cl), 4.19 (2H, t, J ¼ 6 Hz, TsOCH2), 7.36 (2H, d,
J ¼ 8:5 Hz), 7.80 (2H, d, J ¼ 8:5 Hz). 13C-NMR ꢀ: 21.7, 31.7, 40.3,
66.8, 127.9 (ꢀ2), 129.9 (ꢀ2), 132.7, 145.0. IR ꢁmax cmꢃ1: 2968, 1599,
1448, 1360, 1176, 1097, 1001, 935, 816, 667, 575, 555.
1-Chloro-6-methyldecane (13). In a similar manner to that for the
preparation of bromide 11, alcohol 7 was converted to 1-bromo-3-
methylheptane in an 88% yield. To Mg turnings (0.97 g, 40 mmol) in
dry Et2O (30 ml), this bromide (3.5 g, 18 mmol) in dry Et2O (4 ml) was
added while stirring at 0 ꢁC under Ar. After stirring at 0 ꢁC for 1 h, the
mixture was warmed to rt. The produced Grignard reagent B3 was
taken up in a syringe and added dropwise to a solution of tosylate 12
(4.0 g, 16 mmol) and Li2CuCl4 (a 0.1 M THF solution, 1.0 ml) in dry
THF (40 ml) at ꢃ78 ꢁC under Ar. The mixture was gradually warmed
to rt. Stirring was continued for 14 h, the mixture was poured into a
cool H2SO4 solution (1 M, 150 ml), and the product was extracted with
hexane (3 ꢀ 100 ml). After the usual work-up, the extract was
chromatographed over SiO2 (150 g) with elution by hexane to give
13 (2.7 g, 14 mmol, 88%). 1H-NMR ꢀ: 0.84 (3H, d, J ¼ 6:5 Hz,
CH3CH), 0.89 (3H, t, J ¼ 6:5 Hz, CH3CH2), ꢂ1:1 (2H, m), ꢂ1:3
(11H, m), 1.62 (2H, tt, J ¼ 7, 7 Hz, CH2CH2Cl), 3.43 (2H, t, J ¼ 7 Hz,
CH2Cl). 13C-NMR ꢀ: 14.2, 19.7, 23.2, 26.5, 27.2, 29.4, 33.1, 32.7,
32.8, 36.7, 45.0. IR ꢁmax cmꢃ1: 2923, 1466, 1309, 723, 654. GC-MS: tR
8.55 min; m=z 107 (6%), 105 (20%), 93 (31%), 91 (100%).
6-Methyl-1-decanol (10). A mixture of alkyne 9 (6.2 g, 24 mmol),
Pd-C (10%, 700 mg), and MeOH (100 ml) was stirred for two days
under H2 at rt. After filtering off the catalyst, the solvent was
evaporated. The product was chromatographed over SiO2 (150 g) with
elution by hexane/EtOAc (from 10:1 to 2:1) to give 10 (3.1 g,
18 mmol, 75%). 1H-NMR ꢀ: 0.84 (3H, d, J ¼ 6:5 Hz, CH3CH), 0.89
(3H, t, J ¼ 6:5 Hz, CH3CH2), ꢂ1:1 (2H, m), ꢂ1:3 (11H, m), 1.56 (2H,
m, CH2CH2OH), 3.63 (2H, t, J ¼ 6:5 Hz, CH2OH). 13C-NMR ꢀ: 14.2,
19.7, 23.1, 26.1, 26.9, 29.3, 32.7, 32.9, 36.8, 37.0, 63.0. IR ꢁmax cmꢃ1
:
3330, 2931, 1464, 1377, 1055, 729. GC-MS: tR 11.67 min; m=z 154
(½M ꢃ 18ꢄþ, 1%), 97 (66%), 55 (100%).
1-Bromo-6-methyldecane (11). A mixture of the alcohol 10 (2.1 g,
12 mmol), HBr (48%, 5.1 g, 30 mmol), and H2SO4 (590 mg, 6 mmol)
was stirred under a refluxing condition at 120 ꢁC for 6 h. The reaction
mixture was added dropwise to a saturated aqueous solution of
NaHCO3 (100 ml) and extracted with hexane (3 ꢀ 100 ml). After the
usual work-up, the product was chromatographed over SiO2 (100 g)
with elution by hexane to give 11 (2.6 g, 11 mmol, 92%). 1H-NMR ꢀ:
0.84 (3H, d, J ¼ 6:5 Hz, CH3CH), 0.89 (3H, t, J ¼ 6:5 Hz, CH3CH2),
ꢂ1:1 (2H, m), ꢂ1:3 (11H, m), 1.86 (2H, tt, J ¼ 7, 7 Hz, CH2CH2Br),
3.41 (2H, t, J ¼ 7 Hz, CH2Br). 13C-NMR ꢀ: 14.2, 19.7, 23.1, 26.2,
28.5, 29.3, 32.7, 32.9, 34.1, 36.7, 36.8. IR ꢁmax cmꢃ1: 2925, 1464,
6,14-Dimethyl-1-octadecene (3) from chloride 13. To Mg turnings
(0.49 g, 20 mmol) in dry THF (20 ml), a catalytic amount of MeMgBr
(a 2.0 M Et2O solution, two drops) was added under Ar via a syringe.
Next, chloride 13 (1.9 g, 10 mmol) in dry THF (4.0 ml) was added
while stirring at 0 ꢁC under Ar. After stirring at 0 ꢁC for 2 h, the
reaction mixture was warmed to rt, and stirring continued for 2 h. This
Grignard reagent was taken up in a syringe and added to a solution of
A1 (1.5 g, 5.0 mmol) and Li2CuCl4 (a 0.1 M THF solution, 1.0 ml) in

124
T. TAGURI et al.
dry THF (40 ml) in another flask at ꢃ78 ꢁC under Ar. The mixture was
gradually warmed to rt. Stirring was continued for 14 h, the mixture
was poured into an H2SO4 solution (1.0 M, 150 ml), and the product
was extracted with hexane (3 ꢀ 100 ml). After the usual work-up, the
extract was chromatographed over SiO2 (90 g) impregnated with
AgNO3 (10 g) with elution by hexane and hexane/benzene (3:1) to
give 3 (0.57 g, 2.0 mmol, 20% from 13, 40% from A1).
was indicated by the appearance of many small bubbles. After cooling,
the crude product was dissolved in diethylene glycol (DEG, 40 ml), and
.
KOH (2.81 g, 50 mmol) and NH2NH2 H2O (1.6 g, 50 mmol) were
added to the solution. The mixture was stirred at 200 ꢁC for 4 h, and the
mixture was poured into water (300 ml) after cooling. The crude
product was extracted with hexane (3 ꢀ 100 ml) and chromatographed
over SiO2 (100 g) after the usual work-up. Elution with hexane yielded
3 (1.31 g, 4.7 mmol, 39%).
tert-Butyl 7-methyl-3-oxoundecanoate (14). Into a suspension of
NaH (60% in oil, 0.80 g, 20 mmol) with dry THF (15 ml) and HMPA
(3.5 ml), tert-butyl acetoacetate (3.2 g, 20 mmol) was added dropwise
under Ar. The mixture was refluxed at 85 ꢁC for 1 h. After cooling,
BuLi (1.65 M, 13 ml, 21 mmol) was added, and the mixture was stirred
at rt for 30 min. Next, iodide B2 (4.8 g, 20 mmol) in dry THF (5 ml)
was added at 0 ꢁC. After stirring at rt for 1 h, the mixture was poured
into a saturated NH4Cl solution. The crude product was extracted with
EtOAc (3 ꢀ 50 ml) and chromatographed over SiO2 (200 g) after the
usual work-up. Elution with hexane/EtOAc (30:1) yielded 14 (3.8 g,
14 mmol, 70%). 1H-NMR ꢀ: 0.85 (3H, d, J ¼ 6:5 Hz, CH3CH), 0.88
(3H, t, J ¼ 6:5 Hz, CH3CH2), ꢂ1:25 (11H, m), 1.47 (9H, s, C(CH3)3),
2.45 (2H, t, J ¼ 7:5 Hz, CH2CH2C=O), 3.34 (2H, s, O=CCH2C=O).
13C-NMR ꢀ: 14.2, 19.5, 21.0, 23.0, 28.0 (ꢀ3), 29.2, 32.6, 36.4, 36.5,
43.3, 50.7, 81.9, 166.6, 203.6. IR ꢁmax cmꢃ1: 2929, 1738, 1716, 1643,
1458, 1369, 1252, 1149.
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