Syntheses of (Z,E)-5,7-dodecadienol and (E,Z)-10,12-hexadecadienol, lepidoptera pheromone components, via zinc reduction of enyne precursors. Test of pheromone efficacy against the Siberian moth

Article abstract of DOI:10.1021/jf020472s

Efficient syntheses of (Z,E)-5,7-dodecadienol, a pheromone component of the Siberian moth, Dendrolimus superans sibiricus, and (E,Z)-10,12-hexadecadienol, a pheromone component of various Lepidoptera pheromones, were accomplished by cis reduction of the corresponding enynols with activated zinc. The most energetic reagent was zinc galvanized with copper and silver (Zn/Cu/Ag) that achieved rapid and high-yield reduction in methanol-water. The stereoselectivity of semihydrogenation was ≥98%. A process whereby zinc dust was continuously activated throughout the reduction with an acid was also satisfactory (95-98% cis). Field evaluation of the 1:1 mixture of (Z,E)-5,7-dodecadienol and (Z,E)-5,7-dodecadienal with the Siberian moth in Russia showed that the rubber septa pretreated with compound and stored at -80 °C were as effective as freshly treated septa. Moth responses to septa aged in open air indicated that lure effectiveness declined significantly after 2 weeks of aging. Thus, if rubber septa are used as pheromone dispensers in Siberian moth traps monitoring, they should be replaced biweekly with fresh septa for optimal trap effectiveness.

Full text of DOI:10.1021/jf020472s

6366 J. Agric. Food Chem. 2002, 50, 6366−6370
Syntheses of (Z,E)-5,7-Dodecadienol and
E,Z)-10,12-Hexadecadienol, Lepidoptera Pheromone
(
Components, via Zinc Reduction of Enyne Precursors. Test of
Pheromone Efficacy against the Siberian Moth
,
†
†
‡
§
ASHOT KHRIMIAN,* JEROME A. KLUN, YOUSEF HIJJI, YURI N. BARANCHIKOV,
§
|
⊥
VLADIMIR M. PET’KO, VICTOR C. MASTRO, AND MATTHEW H. KRAMER
USDA, ARS, PSI, Chemicals Affecting Insect Behavior Laboratory, Beltsville, Maryland 20705,
Morgan State University, Department of Chemistry, Baltimore, Maryland 21251,
V. N. Sukachev Institute of Forest, Siberian Branch, Russian Academy of Science,
Department of Forest Zoology, 660036 Krasnoyarsk, Russia,
USDA, APHIS, Otis Methods Development Center, Otis ANGB, Massachusetts 02542, and
USDA, ARS, BA, Biometrical Consulting Service, Beltsville, Maryland 20705
Efficient syntheses of (Z,E)-5,7-dodecadienol, a pheromone component of the Siberian moth,
Dendrolimus superans sibiricus, and (E,Z)-10,12-hexadecadienol, a pheromone component of various
Lepidoptera pheromones, were accomplished by cis reduction of the corresponding enynols with
activated zinc. The most energetic reagent was zinc galvanized with copper and silver (Zn/Cu/Ag)
that achieved rapid and high-yield reduction in methanol-water. The stereoselectivity of semi-
hydrogenation was g98%. A process whereby zinc dust was continuously activated throughout the
reduction with an acid was also satisfactory (95-98% cis). Field evaluation of the 1:1 mixture of
(Z,E)-5,7-dodecadienol and (Z,E)-5,7-dodecadienal with the Siberian moth in Russia showed that
the rubber septa pretreated with compound and stored at -80 °C were as effective as freshly treated
septa. Moth responses to septa aged in open air indicated that lure effectiveness declined significantly
after 2 weeks of aging. Thus, if rubber septa are used as pheromone dispensers in Siberian moth
traps monitoring, they should be replaced biweekly with fresh septa for optimal trap effectiveness.
KEYWORDS: (Z,E)-5,7-Dodecadienol; Siberian moth; Dendrolimus superans sibiricus; (E,Z)-10,12-
hexadecadienol; pheromone; zinc reduction
INTRODUCTION
A semiochemical-based monitoring for this species was
recently established with the discovery by Klun et al. (2) that a
:1 blend of (Z,E)-5,7-dodecadien-1-ol (Z5,E7-12:OH) and
Z,E)-5,7-dodecadienal (Z5,E7-12:Ald) was as attractive to
Siberian moth males as virgin females in field trapping
experiments conducted in 1998. A Russian group subsequently
identified Z5,E7-12:OH and Z5,E7-12:Ald in the volatiles
produced by Siberian moth females and reported their attractive-
ness to males in laboratory studies (3). Finally, Chinese scientists
confirmed that the same two compounds are the major phero-
mone components of D. superans (4). Z5,E7-12:OH and Z5,E7-
The Siberian moth, Dendrolimus superans sibiricus Tschet-
verikov, is a destructive defoliator of conifer forests throughout
northern Asia. Recent outbreaks caused severe damage to more
than 8 million hectares of fir and larch forests in Siberia and
the Far East, Russia. This species does not currently occur in
North America, but the moth is a potential threat to U.S. forests
1
(
(1). Should the Siberian moth become established in North
America, it could have an adverse impact on forest environ-
mental quality and production, resulting in economic damage
from restrictive internal and external quarantines on trade.
The capability to monitor potentially damaging exotic insect
populations is critical to preventing the accidental establishment
of invasive insects at ports of entry.
1
2:Ald and their geometric isomers have also been found in
other Dendrolimus spp. (5).
Because the composition of a Siberian moth pheromone had
been positively identified, we decided that it would be appropri-
ate to develop a reliable and easy to scale-up synthetic
methodology for producing large amounts of pheromone for
population monitoring in regions threatened by invasion and
possibly for mass trapping and mating disruption.
*
To whom inquiries should be addressed. Tel: (301) 504-6138. Fax:
(
301) 504-6580. E-mail: khrimiaa@ba.ars.usda.gov.
†
USDA, ARS, PSI, Chemicals Affecting Insect Behavior Laboratory.
‡
Morgan State University.
§
Russian Academy of Science.
|
Z5,E7-12:OH was synthesized in the literature using different
approaches including cis reduction of an enyne precursor with
USDA, APHIS, Otis Methods Development Center.
⊥
USDA, ARS, BA, Biometrical Consulting Service.
1
0.1021/jf020472s CCC: $22.00 © 2002 American Chemical Society
Published on Web 09/26/2002

Syntheses of (Z,E)-5,7-Dodecadienol and (E,Z)-10,12-Hexadecadienol
J. Agric. Food Chem., Vol. 50, No. 22, 2002 6367
a stereodefined trans double bond. This route seemed attractive
due to the availability of starting (E)-7-dodecen-5-yn-1-ol
through the palladium-catalyzed alkylation of tetrahydro-2-(5-
hexynyloxy)-2H-pyran with (E)-1-iodo-1-hexene (6). Ando et
al. (6) reported that Lindlar reduction of (E)-7-dodecen-5-yn-
Scheme 1
1
-ol lacked selectivity, providing a mixture of (Z,E)-diene and
monoenic compounds from which the desired product was
isolated by chromatography on silica impregnated with silver
nitrate. Stille and Simpson (7) used hydroboration of the
protected (E)-7-dodecen-5-yn-1-ol to achieve high yield and
purity of the pheromone. In the present study, we applied an
activated zinc hydrogenation technique to synthesize (Z,E)-5,7-
dodecadien-1-ol from (E)-7-dodecen-5-yn-1-ol. This method was
selected over other cis-reduction techniques because of its
simplicity and propensity to furnish conjugated dienes, including
insect sex pheromones, without significant side reactions (8-
1
3). In particular, zinc activated with copper and silver had been
the reagent of choice in cis reduction of the conjugated trienynes
10). To our knowledge, there were no reports on the use of
(
Zn/Cu/Ag reagent in pheromone synthesis. We also discuss the
application of Zn reduction to the synthesis of (E,Z)-10,12-
hexadecadienol (E10,Z12-16:OH, or bombykol), a sex phero-
mone component of Bombyx mori (L.) (14) that had been
previously synthesized through hydroboration of an enyne
precursor (15). E10,Z12-16:OH and E10,Z12-16:Ald are also
known as pheromone components of several other insects (15,
1
6 and references therein) including the pests pickleworm,
1
-pentyne (1.311 g, 19.28 mmol). The mixture was cooled to 5-10
Diaphania nitidalis (Stoll) (17), and melonworm, Diaphania
hyalinata (L.) (18).
°C, and diisopropylamine (4.16 mL) was added dropwise. After a brown
precipitate formed, the mixture was stirred for 1.5 h and poured into
hexane (100 mL). The mixture was filtered through Celite 521. The
MATERIALS AND METHODS
4
brown solution was washed with saturated aqueous NH Cl, dried with
Na SO , and concentrated. The crude product (2.98 g) was refluxed in
methanol (20 mL) with a few crystals of p-toluenesulfonic acid
monohydrate to remove the THP group. The mixture was worked up
2
4
1
Chemical Analytical Methods. H NMR spectra were recorded in
3
CDCl with TMS as an internal standard on a Bruker QE-300
spectrometer. H NMR coupling constants are reported in Hz. GC was
1
by addition of ∼1 g of NaHCO
3
, removal of most of the MeOH by
performed on a Shimadzu 17A gas chromatograph using a 60 m ×
rotary evaporation, and partitioning the residue between water and
hexane/ether 1:1. The organic extract was washed with brine, dried,
concentrated, and purified by flash chromatography (hexane/ethyl
acetate, 7:3), yielding 6 (1.510 g). The product was further purified by
0
.25 mm RTX-1701 column (Restek Corp.) or a 60 m × 0.25 mm DB
Waxter column (J&W Scientific). Hydrogen was used as a carrier gas.
EI mass spectra (70 eV) were obtained with a Hewlett-Packard 5971
GC-MS equipped with 30 m × 0.25 mm DB-5 (J&W Scientific)
column. Flash chromatography was carried out with 230-400 mesh
silica gel (Whatman). Reagents and solvents were purchased from
Aldrich unless otherwise specified. Tetrahydrofuran (THF) was dried
chromatography on SiO
E)-10-hexadecen-12-yn-1-ol (1.0 g) of g95% purity by GC.
Z,E)-5,7-Dodecadien-1-ol (7, Table 1, Entry 4). Zinc dust (11.16
2 3
-AgNO (hexane/ethyl acetate, 7:3) to give
(
(
g, 279 mmol) from a freshly opened bottle was treated with 25-30
mL of 3% HCl for 1-2 min, and then the liquid was decanted. This
was repeated two more times, after which the zinc slurry was rinsed
repeatedly with distilled water to remove traces of acid. A solution of
copper(II) acetate hydrate (1.556 g, 7.78 mmol) in 20 mL of hot water
was added slowly to the zinc slurry while cooling in an ice bath. The
mixture was stirred for 10-15 min, and a solution of silver nitrate
2
by distillation from sodium-benzophenone ketyl under N . Mention
of a proprietary company or product does not imply endorsement by
the U.S. Department of Agriculture.
Syntheses. The syntheses of the pheromones are outlined in Scheme
1
.
(
E)-1-Iodo-1-hexene (1) was prepared according to Stille and
Simpson (7) by hydroalumination-iodinolysis of 1-hexyne. (E)-Tetra-
hydro-2-[(11-iodo-10-undecenyl)oxy]-2H-pyran (2) was synthesized
by hydrozirconation-iodinolysis of the corresponding tetrahydro-2-
(1.852 g, 10.87 mmol) in 20 mL of water was added likewise. The
resulting mixture was filtered, and the active zinc reagent was sus-
pended in a mixture of 20 mL of MeOH and 30 mL of water. A solution
of (E)-7-dodecen-5-yn-1-ol (1.989 g, 11.11 mmol) in 10 mL of MeOH
was added at once, and the mixture was stirred at 50-60 °C for 11 h
[
(10-undecynyl)oxy]pyran (7). The crude product containing ∼10%
tetrahydro-2-[(10-undecenyl)oxy]-2H-pyran was carried on to the next
step. (E)-Tetrahydro-2-[(5-hexynyl)oxy]-2H-pyran (3) was made by a
standard procedure from the commercially available 5-hexyn-1-ol and
2
under an N atmosphere. Upon completion of the reaction (GC on RTX-
1
701), the unreacted Zn/Cu/Ag was filtered off on a glass filter and
3
,4-dihyro-2H-pyran.
(
washed with 10 mL of MeOH and then with a mixture of 40 mL of
MeOH and 5 mL of 10% HCl. The filtrate was concentrated to remove
most of the MeOH and extracted with 1:1 ether/hexane (5 × 50 mL).
The extract was washed with NH Cl solution, dried with Na SO , and
E)-7-Dodecen-5-yn-1-ol (5) was obtained by the coupling of
compounds 1 and 3 as described in Klun et al. (2) followed by
deprotection of the (E)-tetrahydro-2-[(7-dodecen-5-ynyl)oxy]-2H-pyran.
The compound of 99% purity was used in the reduction step.
E)-10-Hexadecen-12-yn-1-ol (6). The synthesis was accomplished
by coupling of 2 with 1-pentyne (4) according to a procedure described
by McElfresh and Millar (15) for the unprotected (E)-11-iodo-10-
). To a slurry of trans-dichlorobis-
triphenylphosphine)palladium(II) (263 mg, 0.375 mmol, Strem Chemi-
cals) in dry THF (5 mL) were added sequentially a solution of 2 (3.072
g, 8.1 mmol) in THF (20 mL), CuI (263 mg, 1.377 mmol), and
4
2
4
evaporated to leave (Z,E)-5,7-dodecadien-1-ol (7) (1.75 g, 87% yield,
purity 98%). The isomer distributions in the reduction products were
found by acetylation (AcCl, Py) and GC analysis on DB-Waxter
column.
(
undecen-1-ol (2, R
1
) HO(CH
2
)
8
1H NMR: 0.90 (t, J ) 6.5, H-12), 1.20-1.70 (m, 8H, H-2,3,10,11),
(
2.10 (dt, J
) 6.5, H-1), 5.29 (dt, J
) 7.5, H-8), 5.96 (dd, J
1
≈ J
2
) 7.5, H-4), 2.20 (dt, J
) 11.0, J ) 7.5, H-5), 5.67 (dt, J
) J ) 10.5, H-6), 6.29 (dd, H-7). MS:
1
) J
2
) 7.0, H-9), 3.65 (t, J
1
2
1
) 15.0,
J
2
1
2

6368 J. Agric. Food Chem., Vol. 50, No. 22, 2002
Khrimian et al.
Table 1. Cis-Reduction of Acetylenic Alcohols with Zinc
reagent
starting compd
(mmol)
conversion
(%)
stereomeric
purity (%)
product
(isolated yield, %)
a
entry
1
Zn (mmol)
13.8
Cu (mmol)
Ag (mmol)
0.5
solvent/T (°C)
time (h)
5.5
5
0.4
0.2
2.2
7.8
0.2
0.2
MeOH−H2O, 1:1, 60−65
99
81
98
98
99
99
7
7
0.27
2
3
4
5
6
7
8
9
5
6.8
138.0
277.8
7.0
0.3
2.7
MeOH−H2O, 1:1, 50
MeOH−H2O, 1:1, 65−75
MeOH−H2O, 1:1, 50−60
MeOH, 60
14
7
0.27
5
100
100
1
7
(74)
7
5.56
5
10.9
0.3
11
5.5
5.5
15
18
5.5
6.5
2
11.11
(87)
5
0.29
5
7.0
MeOH−H2O, 1:1, 65
MeOH−H2O, 1:1, 60−65
MeOH−H2O, 1:1, 60−65
dioxane−H2O,1:1, 80
MeOH−H2O, 2:1, 60−70
MeOH−H2O, 1:1, 60−70
MeOH−H2O, 1:1, 60−70
77
97
98
95
99
97
98
99
7
7
0.28
5
4.1b
99
0.16
5
138.0c
6.9
100
92
7
(80)
7
5
.6
5
0.2
2.9
0.27
10
6
65.0
688.5
6.9
3.3
26.2
0.3
100
99
8
1.31
(90)
11a
(93)
11b
11
10a
19.3
0.2
2
7.9
10b
.27
12
5
99
0
a
GC analyses of the acetates on DB-Waxter. b Activated with 100 µL of 10% HCl after 10 h. c 2 mL of 10% HCl was slowly added throughout the run.
+
1
(
82 (M , 2), 164 (5), 135 (3), 121 (8), 97 (13), 93 (28), 79 (96), 67
Russia. On the day the vials were shipped, 10 additional septa (treatment
6) were freshly treated with 2 mg of sex attractant and sealed in a
nitrogen-purged vial.
100), 55 (44), 41 (73).
Z,E)-10,12-Hexadecadien-1-ol (8). The reduction was run accord-
ing to Table 1, entry 10. After the workup described above, compound
of 97% purity was isolated by flash chromatography (hexane/ethyl
acetate, 7:3) in 90% yield. H NMR: 0.90 (t, J ) 6.5, H-16), 1.10-
.70 (m, 16H), 2.03-2.18 (m, 4H, H-9, H-14), 3.62 (t, J ) 6.5, H-1),
.29 (dt, J
H-10), 5.94 (dd, J
m/z): 280 (M , 18), 237 (1), 220 (4), 177 (3), 163 (5), 149 (11), 135
21), 121 (29), 109 (23), 96 (50), 81 (66), 67 (100), 55 (29), 43 (50).
Z,E)-5,7-Dodecadienal (9). (Z,E)-5,7-Dodecadien-1-ol (592 mg,
.29 mmol) was oxidized with pyridinium chlorochromate (1.862 g,
.64 mmol) in the presence of sodium acetate (803.6 mg, 9.8 mmol)
in dry methylene chloride (40 mL) at 0 °C, following the procedure
by Corey and Suggs (19) to provide (Z,E)-5,7-dodecadienal (285 mg,
8% yield) after flash chromatography (hexane/ethyl acetate, 95:5).
MS: 180 (M , 15), 151 (7), 136 (20), 79 (100). Purity: 99% by GC.
Z)-2-Dodecen-1-ol (11a) was synthesized according to Table 1,
entry 11, by reduction of 2-dodecyn-1-ol with Zn/Cu/Ag as a reducing
agent. H NMR: 0.88 (t, J ) 7.0, H-12), 1.27 (m, H-5 through H-11,
4 H), 2.08 (dt, J
H-2,3).
Z)-5-[(Tetrahydro-2H-pyran-2-yl)oxy]-2-penten-1-ol (11b) was
prepared by reduction of 5-[(tetrahydro-2H-pyran-2-yl)oxy]-2-pentyn-
-ol with Zn/Cu/Ag (Table 1, entry 12).
1H NMR: 1.30-1.85 (m, 6H), 2.42 (dt, J
m, 2H), 3.80 (m, 2H), 4.14 (d, J ) 6.5, H-1), 4.60 (m, 1H), 5.60 (m,
H-2 or H-3), 5.84 (m, H-2 or H-3). The NMR data are in agreement
with literature values (20).
Insect Trapping. Gray rubber septa (No. 10600275, The West Co.,
Kearney, NE) were extracted with acetone in a Soxhlet extractor prior
to use. Five sets of 10 septa were numbered 1-5 and positioned large
end up on a plastic sheet with double sticky tape. Each septum was
treated with 12.2 µL of a solution containing 164 µg of a 1:1 mixture
of Z5,E7-12:OH and Z5,E7-12:Ald per 1 µL of heptane (2 mg of sex
attractant/septum). The solution was stored at -80 °C when not in use.
Septa (treatments 1-5) were aged in the laboratory (ca. 22 °C) for 0,
(
Trapping studies were conducted in the larch (Larix sibirica, Ledeb.)
forest in the south-eastern foothills of Kuznetskiy Alatau mountains
(Shira region of the Khakass Republic, South Siberia, Russia). We used
standard gypsy moth milk-carton traps (21) with wide (2.5 × 3.0 cm)
entrance holes. A replicate consisted of six traps sequentially baited
with treatments 1-6, and the study consisted of 10 replicates. The traps
were positioned ca. 1.5 m from the ground on the periphery of larch
tree crowns in line with 200-250 m between them along a logging
road through the forest. Moths entering the traps were killed by an
insecticidal (4 cm × 1.3 cm Vapona) strip placed in the bottom of the
trap. Siberian moth population density was low at the location of the
experiment. A standard sampling procedure (22) used in late May for
estimating overwintering 3-4 instar larval density of the species
indicated only 0.08 larvae per tree.
Traps were placed on July 5, 2001, and then checked on July 6, 7,
9, 11, 13, 15, and 17. After being checked, each trap was moved to the
next trap location. Temperature data were collected at 4-h intervals
using two HOBO temperature loggers (ONSET Computer Corp.,
Bourne, MA), positioned in the larch crowns. The average night
temperatures were calculated as an average of four temperature readings
from 8:00 p.m. to 8.00 a.m. During the course of the trapping, the
temperature ranged from 18 to 24 °C, and there were no rainy days.
Statistical Methods. Counts of trapped male moths in each replicate
were summed over a 6-day period (July 6-11). Moth captures declined
after July 11, 2001, and these were not included in the analysis. A
square root transformation of the summed counts was taken to stabilize
the variances. The transformed counts were analyzed using Proc Mixed
in SAS (23), which can estimate mixed linear models, with treatment
as the fixed independent variable and replicate as the random
independent variable. A multiple comparison of all pairs of treatments
was conducted using the Tukey-Kramer p-value adjustment.
8
1
1
5
1
) 10.5, J
2
) 7.5, H-13), 5.64 (dt, J
1
) 15.0, J ) 7.5,
2
1
) J
2
) 11.0, H-12), 6.29 (dd, H-11). MS (acetate,
+
(
(
3
8
4
+
(
1
1
1
) J
2
) 7.0, H-4), 4.20 (d, J ) 5.5, H-1), 5.55 (m,
(
1
1
) J ) 7.0, H-4), 3.47
2
(
RESULTS AND DISCUSSION
The results of the zinc reductions of enyne alcohols 5 and 6
are summarized in Table 1. The active Zn reagent prepared by
treatment of Zn with Cu(OAc)2 and AgNO3 (10) easily and
stereoselectively reduced the enynol 5 in methanol-water
1
4, 28, 53, and 90 days, respectively. At the end of each aging period,
septa were transferred to a screw-cap liquid scintillation vial, purged
with nitrogen, sealed, and held at -80 °C until they were shipped to

Syntheses of (Z,E)-5,7-Dodecadienol and (E,Z)-10,12-Hexadecadienol
J. Agric. Food Chem., Vol. 50, No. 22, 2002 6369
be used by regulatory agencies (such as APHIS) in their
operational program of monitoring this potentially invasive
species in the U.S.
Table 2. Mean Male Siberian Moth Captures and Their Standard
Errors of the Square Root of Summed Counts of Moths Trapped over
a 6 Day Period, with Different Letters Indicating Statistically
Distinguishable Groups
treatment no.
septum age (days)
mean captures/trap
ACKNOWLEDGMENT
1
6
2
3
4
5
0
3.77 (0.27) a
3.31 (0.27) ab
2.43 (0.27) bc
2.03 (0.27) c
0.87 (0.27) d
0.48 (0.27) d
0 (fresh)
14
28
53
90
We thank Dr. James E. Oliver for providing us with the samples
of propargylic alcohols and reviewing the manuscript and Ms.
Melissa Booth for assistance in syntheses.
LITERATURE CITED
(
1
Table 1, entries 1 and 2). Apparently, (Z,E)-5,7-dodecadien-
-ol (7) has high affinity for Zn/Cu/Ag reagent and could be
(1) Baranchikov, Y. N.; Montgomery, M.; Kuchera, D. Siberian
moth: Potential new pest. USDA NE/NA-INF-134-97; U.S.
Government Printing Office: Washington, DC, 1997; Vol. 604,
p 200.
efficiently recovered only after extensive washing of the slurry
with methanol acidified with aqueous HCl (Table 1, entry 4,
compare with methanol only, entry 3). Importantly, the reduction
was very clean, and further purification of 7 was not necessary.
Several reduction procedures involving a Zn/Cu reagent have
been reported using an alcohol as solvent (11, 24). However,
the reduction of 5 with Zn/Cu/Ag in pure MeOH was totally
inefficient (Table 1, entry 5). A Zn/Cu reagent was found
effective if the reduction was run in a dioxane-water mixture
(
2) Klun, J. A.; Baranchikov, Y. N.; Mastro, V. C.; Hijji, Y.;
Nicholson, J. M.; Ragenovich, I.; Vshivkova, T. A. A sex
attractant for the Siberian moth Dendrolimus superans sibiricus
(Lepidoptera: Lasiocampidae). J. Entomol. Sci. 2000, 35, 158-
1
66.
(
3) Pletnev, V. A.; Ponomarev, V. L.; Vendilo, N. V.; Kurbatov, S.
A.; Lebedeva, K. V. A search for the pheromone of the Siberian
moth Dendrolimus superans sibiricus (Lepidoptera: Lasiocam-
pidae). Agrokhimia 2000, 67-72 (Russian).
(
Table 1, entry 9), apparently because of higher reaction
temperature (9). Interestingly, with Zn powder taken from a
fresh bottle and activated with acid before use, the reduction of
(4) Kong, X.; Zhao, C.; Gao, W. Identification of the sex pheromones
of four economically important species in genus Dendrolimus.
Chin. Sci. Bull. 2001, 46, 2077-2081.
(E)-7-dodecen-5-yn-1-ol stalled at about 20% conversion but
(
(
5) Arn, H. The Pherolist, http://www.nysaes.cornell.edu/pheronet/.
6) Ando, T.; Vu, M. H.; Yoshida, S.; Takanishi, N. Stereoselective
synthesis of some isomers of dodecadien-1-ol: Compounds
related to the pine moth sex pheromone. Agric. Biol. Chem. 1982,
was driven nearly to completion by adding some aq HCl to the
mixture (Table 1, entry 7). On a larger scale, adding 10% HCl
slowly throughout the run allowed the reduction to go to
completion with reasonably good stereochemistry (Table 1,
entry 8). M a¨ eorg and Timoteus (9) reported that the most
vigorous cis reduction of the triple bond with Zn/Cu occurred
at pH ∼6 and below. It appears that not only the reduction rate
but also the stereochemistry may be dependent on the amount
of acid added. Thus, an optimum pH could possibly be found
to promote the reaction but not to significantly decrease cis
stereoselectivity. Zn/Cu/Ag reagent was also very efficient in
the semi-hydrogenation of enynol 6 providing E10,Z12-16:OH
4
6, 717-722.
(
7) Stille, J. K.; Simpson, J. H. Stereospecific palladium-catalyzed
coupling reactions of vinyl iodides with acetylenic tin reagents.
J. Am. Chem. Soc. 1987, 109, 2138-2152.
(8) M a¨ eorg, U. Zinc-copper couple as a reducing agent. I. Reduction
of some enynols and alkynols. Tartu Ulik. Toim. 1982, 616, 50.
(9) M a¨ eorg, U.; Timoteus, H. Zinc-copper couple as a reducing
agent. 2. Modification of the catalyst and effect of the medium
on reduction of triple bond. Proc. Acad. Sci. Estonian SSR Chem.
1985, 34, 180-184 (Russian).
10) Boland, W., Schroer, N., Sieker, C. 96. Stereospecific syntheses
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New hydrocarbons from the marine brown alga Giffordia
mitchellae. HelV. Chim. Acta 1987, 70, 1025-1040.
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Synth. Commun. 1990, 20, 3421-3425.
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(13) Negishi, E.; Yoshida, T.; Abramovitch, A.; Lew, G.; Williams,
R. H. Highly stereoselective synthesis of conjugated E,E- and
E,Z-dienes, E-enynes and E-1,2,3-butadienes via alkenylborane
derivatives. Tetrahedron 1991, 47, 343-356.
14) Butenandt, A.; Beckman, R.; Stamm, D.; Hecker, F. U¨ ber den
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sheep moth, Hemileuca eglanterina, from the San Gabriel
mountains of California. J. Chem. Ecol. 1999, 25, 687-709.
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components of the buck moth, Hemileuca maia. J. Chem. Ecol.
(8) in 90% yield (Table 1, entry 10). The last two entries in
(
Table 1 demonstrate the applicability of the Zn/Cu/Ag reagent
to the rapid and highly stereoselective cis reductions of
propargylic alcohols. The resulting allylic alcohols are useful
intermediates in pheromone syntheses. (Z,E)-5,7-Dodecadien-
1
5
the aldehyde was loaded on rubber septa at the 2 mg dose (see
above).
Results of the trapping experiment in Russia are shown in
Table 2. Clearly, the 1:1 mixture of Z5,E7-12:OH and Z5,E7-
(
-ol (7) was oxidized with pyridinium chlorochromate to (Z,E)-
,7-dodecadienal (9). The 1:1 (w/w) blend of the alcohol and
(
1
2:Ald was biologically effective. There were significant
differences among treatments, with longer-aged lures attracting
fewer moths. Since treatments 1 and 2 (with a lure age difference
of 2 weeks) were significantly different, these results indicate
that it is necessary to replace the lures at intervals of less than
(
(
(
(
2
weeks to best monitor Siberian moth populations. There was
no significant difference between treatments 1 and 6, demon-
strating that the compounds store well for at least a 90-day
period on the gray rubber septa in a nitrogen atmosphere at
-
80 °C.
In conclusion, activated zinc reduction was efficiently applied
2
001, 27, 1409-1422.
in preparation of the two dienic sex pheromones from the
corresponding enynes. The results on formulation and trapping
the Siberian moth with the synthetic pheromone mixture could
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K. Female sex pheromone of the pickleworm, Diaphania nitidalis
(Lepidoptera: Pyralidae). J. Chem. Ecol. 1986, 12, 239-249.

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(
18) Raina, A. K.; Klun, J. A.; Schwarz, M.; Day, A.; Leonhardt, B.
A.; Douglass, L. W. Female sex pheromone of the melonworm,
Diaphania hyalinata (Lepidoptera: Pyralidae), and analysis of
male responses to pheromone in a flight tunnel. J. Chem. Ecol.
(22) Il’inskiy, A. I. Management, sampling and prognosis of the
mass outbreaks of the needle- and leaf-chewing insects in the
USSR forests. In Lesnaya Promyshlennost’, Moscow 1965, 525
(Russian)
1
986, 12, 229-237.
(23) SAS Institute Inc. SAS/STAT User’s Guide, version 8; SAS
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(24) Sondengam, B. L.; Charles, G.; Akam, T. M. A novel stereo-
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(
19) Corey, E. J.; Suggs, J. W. Pyridinium chlorochromate. An
efficient reagent for oxidation of primary and secondary alco-
hols to carbonyl compounds. Tetrahedron Lett. 1975, 2647-
2
650.
(
20) Sharma, M. L.; Gupta, R.; Verma, S. Syntheses of some cis
mono-olefinic insect sex pheromones. Collect. Czech. Chem.
Commun. 1991, 56, 1744-1748.
Received for review April 23, 2002. Revised manuscript received July
29, 2002. Accepted August 7, 2002.
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Dosage effects. J. Chem. Ecol. 1988, 14, 581-588.
JF020472S