Pheromone synthesis. Part 255: Synthesis and GC-MS analysis of pheromonal triacylglycerols of male Drosophila fruit flies

Article abstract of DOI:10.1016/j.tet.2014.06.049

Pheromonal triacylglycerols and their analogs, 1A, 1B, 2A, 2B, 3A, 3B, and 3C, of male Drosophila fruit flies were synthesized and analyzed by GC-MS. Their GC retention times were found to be a reliable measure to analyze and identify these triacylglycerols with acetyl, oleoyl and tigloyl groups, although the stereo- and regioisomers of 1 (1A and 1B), 2 (2A and 2B), and 3 (3A, 3B, and 3C) could not be distinguished from each other by MS alone.

Full text of DOI:10.1016/j.tet.2014.06.049

Tetrahedron 70 (2014) 5752e5762
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Pheromone synthesis. Part 255: Synthesis and GCeMS analysis of
q
pheromonal triacylglycerols of male Drosophila fruit flies
Kenji Mori *
Photosensitive Materials Research Center, Toyo Gosei Co., Ltd, 4-2-1 Wakahagi, Inzai-shi, Chiba 270-1609, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 26 May 2014
Received in revised form 12 June 2014
Accepted 13 June 2014
Available online 18 June 2014
Pheromonal triacylglycerols and their analogs, 1A, 1B, 2A, 2B, 3A, 3B, and 3C, of male Drosophila fruit flies
were synthesized and analyzed by GCeMS. Their GC retention times were found to be a reliable measure
to analyze and identify these triacylglycerols with acetyl, oleoyl and tigloyl groups, although the stereo-
and regioisomers of 1 (1A and 1B), 2 (2A and 2B), and 3 (3A, 3B, and 3C) could not be distinguished from
each other by MS alone.
Ó 2014 Elsevier Ltd. All rights reserved.
Keywords:
1,3-Diacylglycerols
Di(n-butyl)tin oxide
Drosophila fruit flies
GCeMS analysis
Pheromone
Triacylglycerols
1. Introduction
and enzymatic7 approaches have been reported recently together
with development of reliable methods for determination of their
Triacylglycerols (TAGs) are naturally occurring and abundant
tricarboxylic esters of glycerol. Although triacylglycerol I (Fig. 1)
with the same three acyl groups as well as another symmetrical one
II are achiral, triacylglycerols such as III and IV are dissymmetric
and chiral. Synthesis of enantiopure triacylglycerols is a long-
enantiomeric purity.
In 2011 Yew et al. demonstrated the presence of triacylglycerols
in cuticles of two species of Drosophila fruit flies, Drosophila arizo-
nae and Drosophila mojavensis. The structures of some of the tri-
acylglycerols were then proposed (Figs. 2 and 3), which were new
and unusual to be comprised of zero or one acetic acid, two or one
8
2
3e6
standing challenge to chemists, and several new chemical
9
tiglic acid(s), and a fatty acid. These triacylglycerols are secreted by
male flies from the ejaculatory bulb, transferred to females during
mating, and inhibit courtship from other males. Accordingly, Dro-
9
sophila triacylglycerols are a novel class of pheromones. Mori’s
synthetic triacylglycerols including (R)- and (S)-1,2-ditigloyl-3-
3
oleoylglycerol (1A) were bioassayed against Drosophila fruit flies,
and (R)-1A was found to suppress copulation of the flies at a dosage
9
of 75 ng per female, while (S)-1A was inactive. This is another
example to show the important role of chirality in chemical
10,11
communications.
However, there was an ambiguity with regard to the proposed
structure 1A of the natural triacylglycerol as pointed out by Francke
in the course of the reviewing process of Ref. 9. The structure 1A
was proposed totally basing upon the mass spectroscopic (MS)
analysis of the natural product. Is it possible to discriminate 1A
from 1B on the basis of the MS data alone? Due to the scarcity of the
Fig. 1. Four structural types IeIV of triacylglycerols.
1
13
natural triacylglycerol, none of its IR, H and C NMR data was
q
For Part 254, see Ref. 1.
Tel.: þ81 3 3816 6889; fax: þ81 3 3813 1516; e-mail address: kjk-mori@arion.
13
available. Of course C NMR analysis would be an appropriate tool
*
to discriminate 1A from 1B, because the latter is a symmetrical
ocn.ne.jp.
http://dx.doi.org/10.1016/j.tet.2014.06.049
0
040-4020/Ó 2014 Elsevier Ltd. All rights reserved.

K. Mori / Tetrahedron 70 (2014) 5752e5762
5753
type IV triacylglycerol is not yet known precisely, it is important to
provide the enantiomers of 3A, 3B, and 3C for bioassay.
The present paper describes in detail the synthesis and analysis
of Drosophila triacylglycerols, and recommends the GCeMS analy-
12
sis for their identification.
2
2
. Results and discussion
.1. Synthesis of triacylglycerols 1A and 2A
Synthesis of the pheromonally active (R)-1,2-ditigloyl-3-
3
oleoylglycerol (1A) was executed by the published method as
shown in Scheme 1. Acylation of (R)-2,3-acetoneglycerol (4) with
oleoyl chloride was followed by deprotection with 80% acetic acid
ꢀ
at 50 C for 2 h to give (S)-1-oleoylglycerol (5), whose enantiomeric
1
purity was determined as >98% ee by the H NMR analysis of the
corresponding bis-(R)-a-methoxy-a-trifluoromethylphenylacetic
3
(MTPA) ester.
Fig. 2. Two candidate structures (R)-1A and 1B of the triacylglycerol pheromone of
3
male Drosophila fruit flies. Synthetic (R)-1A suppresses the fly copulation at a dose of
7
5 ng per female, while (S)-1A is inactive.9 Structures 2A and 2B of two non-natural
analogs are also shown.
Scheme 1. Synthesis of triacylglycerols (R)-1A, (R)-2A, and (S)-2A. Reagents: (a) oleoyl
chloride, DMAP, C
5
H
5
N, C
6
H
6
[94% for (R)-isomer; 96% for (S)-isomer]; (b) 80% AcOH,
N, C [76% for
N [80% for (R)-2A]; acetic anhydride, DMAP, C
ꢀ
50
C, 2 h [94% for (R)-5; 99% for (S)-5]; (c) tigloyl chloride, DMAP, C
5
H
5
6 6
H
(
[
R)-1A]; (d) acetyl chloride, C
83% for (S)-2A].
H
5 5
5 5
H N
Acylation of (S)-5 with excess tigloyl chloride afforded the
2
1
known (R)-1A, [
a
]
D
þ4.11 (c 4.13, hexane), in 67% overall yield
based on (R)-4 (three steps). Acylation of (S)-5 with excess acetyl
chloride furnished (S)-1,2-diacetyl-3-oleoylglycerol (2A),
2
3
[a]
D
ꢁ
0.88 (c 4.19, hexane). Similarly, (S)-4 was converted to (R)-2A,
2
4
[
(
(
a
]
D
þ1.33 (c 4.02, hexane). The overall yield of (R)-2A and that of
S)-2A were 71% and 78%, respectively, based on (S)-4 and (R)-4
three steps).
Fig. 3. Three candidate structures (S)-3A, (S)-3B, and (R)-3C for a Drosophila tri-
acylglycerol with an acetyl, an oleoyl and a tigloyl groups. Their opposite enantiomers
are also the candidates.
2.2. Synthesis of symmetrical triacylglycerols 1B and 2B
Scheme 2 summarizes the synthesis of two symmetrical tri-
molecule. It therefore became necessary to synthesize 1B, and find
out a method to distinguish 1A from 1B. For the purpose of ana-
lyzing a similar case, non-natural diacetyloleoylglycerols, (R)- and
acylglycerols, 1,3-ditigloyl-2-oleoylglycerol (1B) and 1,3-diacetyl-2-
oleoylglycerol (2B). Although pure 1B could be obtained by the
depicted synthetic scheme, 2B could not be secured in pure state.
Synthesis of 1B started from (ꢂ)-2,3-acetoneglycerol (4). Acyl-
ation of (ꢂ)-4 with tigloyl chloride gave (ꢂ)-6, which was stirred
(S)-2A and 2B, were also chosen as the synthetic targets.
Another objective of the present work was to determine the
ꢀ
substitution pattern of the Drosophila triacylglycerol(s) of type IV
Fig.1) with an acetyl, an oleoyl and a tigloyl groups. Six isomers are
possible for that triacylglycerol(s) of type IV as shown in Fig. 3: (S)-
A, (S)-3B and (R)-3C as well as their opposite enantiomers. It was
with 80% acetic acid and heated at 130 C for 10 min. The mixture
(
was concentrated in vacuo, and the residue was diluted with tol-
uene. The solution of (ꢂ)-7 in toluene was again concentrated in
vacuo to give (ꢂ)-7 as a viscous oil. Selective mono-acylation of
(ꢂ)-7 to give 1,3-ditigloylglycerol (8) was executed by treatment
with an equivalent amount of tigloyl chloride in the presence of
3
therefore planned to synthesize and analyze all of them to find out
a method for establishing (at least) the substitution pattern of the
natural triacylglycerol(s) of type IV. Since the biological role of the
2 2
di(n-butyl)tin oxide and triethylamine in CH Cl under the

5754
K. Mori / Tetrahedron 70 (2014) 5752e5762
GCeMS comparison with (R)-2A. It is to be noted that tigloyl mi-
gration in the case of 1,3-ditigloylglycerol (8) is a far less facile
process.
2.3. Alternative synthesis of 1,3-diacylglycerols 8 and 11
An alternative synthetic route for 1,3-diacylglycerols 8 and 11
was also explored as shown in Scheme 3. Commercially available
,3-dihydroxyacetone dimer (13) in pyridine was treated with ex-
1
cess tigloyl chloride to give crystalline 1,3-ditigloyloxyacetone (14),
ꢀ
mp 46.0e46.5 C, in 91% yield after chromatographic purification.
Reduction of 14 with zinc borohydride in THF furnished 1,3-
ditigloylglycerol (8) in quantitative yield. The above preparative
method is superior to the previous one [(ꢂ)-4/8] in view of the
better yield, shorter steps, and less complicated experimental
procedures.
Scheme 3. Alternative synthesis of 8 and 11. Reagents: (a) tigloyl chloride, C
5 5 6 6
H N, C H
(91%); (b) Zn(BH
4 2
) , THF [quant. for 8; 61% for a 2:1 mixture of 11 and (ꢂ)-12].
When the above synthetic method was used for the preparation
of 11, it resulted in failure, although a successful case was recorded
1
5
Scheme 2. Synthesis of triacylglycerols 1B and 2B. Reagents: (a) tigloyl chloride,
in 1986. Acetylation of 13 with acetic anhydride and pyridine gave
ꢀ
DMAP, C
ꢂ)-10]; (c) (n-Bu)
N, C
[77% for 1B; 87% for 2Bþ(ꢂ)-2A]; (e) acetyl chloride, DMAP, C
quant.); (f) (n-Bu) SnO, Et N, acetyl chloride, CH Cl (86%).
5
H
5
N, C
6
H
6
(quant.); (b) 80% AcOH, 130 C, 10 min [quant. for (ꢂ)-7; 97% for
crude 15 as a colorless solid, which was recrystallized from EtOAc/
hexane to give 15 as needles in 75% yield.
zinc borohydride [prepared from sodium borohydride (washed
with EtOAc to remove alkaline impurities) and zinc chloride in
THF] unfortunately afforded a 2:1 mixture of 11 and (ꢂ)-12 in 61%
yield. Extremely facile acetyl migration in the course of the re-
duction could not be avoided in my hands. In the successful case
reported in 1986, zinc borohydride in Et
reducing agent. Acylation of the resulting mixture of 11 and
(
C
(
2
SnO, Et
3
N, tigloyl chloride, CH
2
Cl
2
(70%); (d) oleoyl chloride, DMAP,
6 6
N, C H
15,16
Reduction of 15 with
H
5 5
6
H
6
H
5 5
2
3
2
2
16
conditions reported by Martinelli et al. for the selective mono-
13
tosylation of 1,2-diols. Regioselective alkylation and esterification
of a specific hydroxyl group via organotin intermediates are well
2
O was employed as the
14
15
established methods as reviewed by David and Hanessian. In the
present case, (ꢂ)-7 afforded 8 (98.8% purity by GCeMS analysis) in
(
ꢂ)-12 with oleoyl chloride furnished a mixture of 2B and (ꢂ)-2A.
7
0% yield. Acylation of 8 with oleoyl chloride afforded 1B in 77%
Unfortunately, therefore, pure 2B could not be secured.
yield. The structure 1B assigned to the product was consistent with
13
its C NMR spectrum, in which only two signals (
d 167.4 and 172.9)
for C]O carbons and four signals ( 128.0, 129.7, 130.0, 138.2) for
d
2.4. Synthesis of the enantiomers of chiral triacylglycerols 3A,
3B, and 3C
C]C carbons could be observed owing to its molecular symmetry.
The overall yield of 1B was 54% based on (ꢂ)-4 (four steps).
Similarly, acetylation of (ꢂ)-4 gave (ꢂ)-9, which was depro-
tected with hot 80% acetic acid to furnish (ꢂ)-1-acetylglycerol (10).
Its di(n-butyl)tin oxide-catalyzed monoacetylation, however, gave
a 65:35 mixture of the desired 11 and unwanted (ꢂ)-12 instead of
pure 11. It must be due to the extremely facile acetyl migration from
C-1 to C-2. Since 11 could not be separated from (ꢂ)-12 by con-
ventional silica gel chromatography, the mixture was acylated with
oleoyl chloride to give a 2:1 mixture of the desired 2B and un-
desired (ꢂ)-2A. The minor component was identified as (ꢂ)-2A by
The synthetic plan for these chiral triacylglycerols 3A, 3B, and 3C
was to employ the di(n-butyl)tin oxide-catalyzed terminal acyla-
tion of monoacylglycerols 5 and 7. However, the facile acyl migra-
tion in the course of the final acylation at C-2 might cause severe
decrease in the purity of the desired products 3A, 3B, and 3C.
Notwithstanding the above problem, the synthesis of (S)-3A
started from (S)-5. Treatment of (S)-5 with acetyl chloride in the
13
presence of di(n-butyl)tin oxide and triethylamine in CH
2
Cl
2
was
followed by chromatographic purification to give (S)-16 (90.1% pure

K. Mori / Tetrahedron 70 (2014) 5752e5762
5755
by GCeMS analysis) in 82% yield. Acylation of (S)-16 with tigloyl
chloride in the presence of 4-dimethylaminopyridine (DMAP) and
pyridine unfortunately caused extensive acyl migration. The
product was a mixture of (S)-3A (62.3%), (R)-3C (15.6%; generated
by 1/2 acetyl migration), and (S)-3B (11.1%; generated by 1/2
oleoyl migration). Fortunately, the desired (S)-3A was the major
component, and the product could be used successfully as a refer-
ence sample for the subsequent analytical works.
2 2
in CH Cl to give (R)-18 (99.1% pure as determined by GCeMS
analysis). Acetylation of (R)-18 with acetyl chloride and DMAP in
pyridine afforded (R)-3C (71.5% pure). The by-products were (S)-3A
(13.7%; generated by 1/2 tigloyl migration) and (R)-3B (4.9%;
generated by 1/2 oleoyl migration).
Similarly, (R)-5 was converted to (R)-3A [79.6% pure by GCeMS;
contaminated with (R)-3B (3.2%) and (S)-3C (7.7%)]. (S)-1-
Oleoylglycerol (5) was converted to (R)-3B [64.3% pure by
GCeMS; contaminated with (R)-3C (28.8%)], and (R)-5 was con-
verted to (S)-3C [74.9% pure by GCeMS; contaminated with (R)-3A
(5.7%) and (S)-3B (2.9%).
(R)-1,2-Acetoneglycerol (4) was the starting material for the
synthesis of (S)-3B. As described in Section 2.2 for the conversion of
(
ꢂ)-4 to (ꢂ)-7, (R)-4 was converted to (S)-1-tigloylglycerol (7) via
22
(S)-6. The enantiomeric purity of (S)-7, [
a]
D
ꢁ2.28 (c 4.50, CHCl
3
),
3
was 90% ee as determined by Mosher’s MTPA/NMR method.
Acetylation of (S)-7 with acetyl chloride in the presence of di(n-
2.5. Comments on the acylation of 1-acyl- and 1,3-
diacylglycerols
2 2
butyl)tin oxide and triethylamine in CH Cl afforded (S)-17, which
was 99.5% pure by its GCeMS analysis. Treatment of (S)-17 with
oleoyl chloride in the presence of DMAP and pyridine gave a mix-
ture of triacylglycerols, whose major component was desired (S)-3B
2.5.1. Selective acylation is possible at C-3 of 1-acylglycerol. 1-
Acylglycerols could be acylated selectively at C-3 by treatment
with acyl chloride in the presence of di(n-butyl)tin oxide and
triethylamine to give 1,3-diacylglycerols. As described in 2.4, 1,3-
diacylglycerols (S)-16, (S)-17 and (R)-18 could be secured in 90.1%,
(
62.6%) contaminated with 26.6% of (S)-3C, which was generated by
/2 acetyl migration prior to the oleoylation (Scheme 4).
1
9
3
9.5% and 99.1% purity, respectively, by the selective acylation at C-
. Martinelli’s di(n-butyl)tin oxide-catalyzed acylation is an ex-
13
cellent method for the preparation of 1,3-diacylglycerols.
2.5.2. 1/2 Acyl migration prevents the synthesis of pure tri-
acylglycerols. Acylation at C-2 of 1,3-diacylglycerols 16, 17 and 18
ought to give triacylglycerols 3A, 3B, and 3C, respectively, with
newly introduced acyl group at C-2, if there is no acyl migration
prior to the acylation reaction. When the acylation was actually
carried out, the results were surprising and disappointing after
GCeMS analysis of the products. As shown in Table 1, the generated
3A, 3B, and 3C were not pure.
Fortunately, the expected products were the major components
in each case. But cross-contamination with other triacylglycerols
took place. Prior to the acylation with the respective acyl chloride,
the starting 1,3-diacylglycerol suffered from 1/2 (or 3/2) acyl
migration to give 1,2-diacylglycerols, whose subsequent acylation
yielded undesired triacylglycerol(s).
The results listed in Table 1 indicate that the ease of migration is
acetyl>tigloyl>oleoyl. The acetyl group was so easily transferred to
C-2 that in the case of the oleoylation of 1-acetyl-3-tigloylglycerol
(17), no tigloyl-migrated product 3A could be detected as can be
seen from (B). It is also to be noted that the tigloyl group is more apt
to migrate than the oleoyl group as seen from the results in (C).
Through the acylation experiments, an important lesson was
learned that the acyl migration prevents the synthesis of pure tri-
acylglycerols from 1,3-diacylglycerols. Fig. 4 shows a possible
mechanism for the acyl migration, giving a mixture of 3a, 3b, and 3c
instead of pure 3a.
2.6. Spectroscopic comparison of the synthetic samples of
Drosophila triacyglycerols
It was previously reported that (R)-1A was pheromonally active
9
against male Drosophila fruit flies. However, there was no strong
reason to exclude 1B as the correct structure of the natural pher-
omone. Various spectra of (R)-1A and1B were therefore compared
whether the two isomers exhibit different spectral properties or
not.
Scheme 4. Synthesis of triacylglycerols 3A, 3B, and 3C. Reagents: (a) (n-Bu)
acetyl chloride, CH Cl [73% for (S)-16; 71% for (R)-16; 70% for (S)-17; 71% for (R)-17];
b) tigloyl chloride, DMAP, C N, C [71% for (S)-3A; 78% for (R)-3A]; (c) oleoyl
[91% for (S)-3B, 82% for (R)-3B]; (d) (n-Bu) SnO, Et N,
[99% for (R)-18; quant. for (S)-18]; (e) acetyl chloride, DMAP,
2 3
SnO, Et N,
2
2
The IR spectrum of (R)-1A was almost identical with and in-
1
(
5
H
5
6 6
H
distinguishable from that of 1B. The H NMR spectrum of (R)-1A
chloride, DMAP, C
tigloyl chloride, CH
N, C
5
H
5
N, C
6
H
6
2
3
was slightly different from that of 1B, because the molecular
2
Cl
2
3 2
symmetry of 1B made both the CH C]C and OCH signals simpler
C
H
5 5
H
6 6
[83% for (R)-3C; 73% for (S)-3C].
than the corresponding signals of (R)-1A. Differences were more
13
For the preparation of (R)-3C, (S)-5 was treated with tigloyl
chloride in the presence of di(n-butyl)tin oxide and triethylamine
evident in the C NMR spectra of (R)-1A and 1B. Two signals (
d 62.2
and 62.3) were observed for the CH O carbons of (R)-1A, while only
2

5756
K. Mori / Tetrahedron 70 (2014) 5752e5762
Table 1
Migration of the acyl group at position 1 or 3 in the course of the acylation at position 2 of 1,3-diacylglycerols 16, 17 and 18 to give triacylglycerols 3A, 3B, and 3C, respectively.
A¼CH COe; OL¼(Z)-n-C 17CH]CH(CH COe; T¼(E)-CH CH]C(CH )COe
3
8
H
2
)
7
3
3
2
a single signal (d 62.5) was observed for the CH O carbons of 1B due
to its symmetrical structure. Similarly, six C]C signals and three
C]O signals were observed for (R)-1A, while 1B exhibited only four
C]C signals and two C]O signals due to its molecular symmetry.
However, these NMR differences were of no use in the present case,
because the Drosophila triacylglycerols were detected and analyzed
by MS alone, and their pure samples were unavailable in an amount
13
sufficient for C NMR measurements.
It was therefore of utmost importance to compare the mass
spectrum of (R)-1A with that of 1B. As shown in Fig. 5, the mass
spectrum of (R)-1A was almost identical with and indistinguishable
from that of 1B. This result annoyed me, because it meant that all of
the spectroscopic methods were inappropriate for the identifica-
tion of the nanogram amounts of the Drosophila triacylglycerols.
Fig. 4. Acyl migration in the course of the acylation of a 1,3-diacylglycerol prevents the
formation of the pure triacylglycerol 3a and gives a mixture of 3a, 3b, and 3c.
Fig. 5. Mass spectra (EI, 70 eV) of (R)-1A and 1B. They are almost the same.

K. Mori / Tetrahedron 70 (2014) 5752e5762
5757
The mass spectra of (S)-3A, (R)-3B, and (R)-3C were also almost
identical to each other as shown in Fig. 6, and could not be used for
the identification of each of them. It must be added that their IR and
NMR data were also identical, and useless for the purpose of
identification.
Fig. 7(a) shows the chromatogram obtained by the co-injection
experiment for (R)-1A and 1B. They were cleanly separable:
t
R
¼24.6 min for (R)-1A and 24.8 min for 1B. Accordingly, identifi-
cation of the Drosophila pheromone must be possible by carrying
out GC (or LC)-MS co-injection experiments with the synthetic
samples (R)-1A and 1B.
Fig. 7. GC separation of (a) a 1:2 mixture of (R)-1A and 1B and (b) a 1:2:4 mixture of
(
S)-3A, (S)-3B, and (R)-3C. Instrument: Agilent 5975 inert XL; Column: HP-5MS, 5%
phenylmethylsiloxane, 30 mꢃ0.25 mm i.d.
As shown in Fig. 7 (b), a 1:2:4 mixture of the synthetic (S)-3A,
Fig. 6. Mass spectra (EI, 70 eV) of (S)-3A, (S)-3B, and (R)-3C. They are very similar to
each other.
(
(
R
S)-3B, and (R)-3C was also separable by GCeMS:t ¼21.3 min for
S)-3A, 21.4 min for (S)-3B and 21.6 min for (R)-3C. The Drosophila
triacylglycerols with an acetyl, an oleoyl and a tigloyl group can
therefore be identified by GC (or LC)eMS co-injection experiments,
although their absolute configuration remains unknown. A suitable
chiral stationary phase for the enantiomer identification must be
found out.
2
.7. Chromatographic analysis of the Drosophila
triacylglycerols
At this stage it seemed hopeless to discriminate (R)-1A from 1B,
because their mass spectra were almost the same. Their GC re-
HPLCeMS methods are known to be useful in determining the
ratio of positional isomers of triacylglycerols in vegetable oils.
17e19
tention times were not so much different either [t
R)-1A and t
lyzed separately. Even with these very small difference in their
R
¼24.7 min for
(
R
¼24.8 min for 1B; see Fig. 5], when they were ana-
These HPLCeMS methods were also examined for the analysis of
Drosophila triacylglycerols. Separation was possible only in the
19
retention times, GC co-injection experiment of a 1:2 mixture of (R)-
case of (R)-1A and 1B by employing the method of Nagai et al.
1
A and 1B was attempted, because in the case of GCeMS analysis of
Neither a mixture of 2A and 2B nor a mixture of 3A, 3B, and 3C
could be separated. Therefore, in the case of the Drosophila tri-
acylglycerols, analysis by GCeMS is preferable to HPLCeMS
analysis.
a 1:2 mixture of 2A and 2B, a very small difference (0.035 min) in
their retention times could be detected as two partially resolved
peaks.

5758
K. Mori / Tetrahedron 70 (2014) 5752e5762
þ
3
. Conclusion
380 (6) [M ꢁAcOH], 265 (22), 264 (28), 159 (100), 43 (45); HRMS
þ
calcd for C25H O Na : 463.3030, found: 463.3030.
44 6
Synthesis of 1,3-diacylglycerols was achieved by selective acyl-
2
3
ation of 1-acylglycerols with acyl chlorides in the presence of di(n-
butyl)tin oxide and triethylamine. Acylation of 1,3-diacylglycerols
with different acyl chlorides in the presence of DMAP and pyri-
dine was found to be accompanied with acyl migration of the pre-
existing acyl group(s), and therefore the resulting triacylglycerols
were mixtures of positional isomers, whose major component was
the desired one.
4.3.2. (S)-Isomer. Similarly, (S)-5 {[
enantiomerically pure as determined by MTPA-NMR analysis;
724 mg, 2.04 mmol} in pyridine (5 mL) was treated with Ac
(1 mL, excess) and DMAP (50 mg) for 3 d in a refrigerator to give
a
]
D
þ3.22 (c 4.57, pyridine),
3
2
O
19
23
746 mg (83%) of (S)-2A as a colorless oil, n
4.19, hexane); GCeMS [same conditions as those for (R)-1A]: t
19.39 min (88.3%). Its IR, H and C NMR, and MS spectral data
D
¼1.4569; [
a]
D
ꢁ0.88 (c
R
1
13
Preliminary bioassay by Yew et al. of (R)-1A and 1B showed the
former to be far more active than the latter as the Drosophila
pheromone. The final identification of the natural triacylglycerols
as well as the bioassay of all of the synthetic samples will be re-
ported by Yew and her co-workers in due course.
were identical to those reported for (R)-2A. HRMS calcd for
þ
C
25
H
44
O
6
Na : 463.3030, found: 463.3030.
4.4. 1-Tigloyl-2,3-acetoneglycerol (6)
4
C H
6 6
.4.1. Racemate. A solution of tigloyl chloride (1.18 g,10 mmol) in dry
(5 mL) was added dropwise to a stirred and ice-cooled solution
of (ꢂ)-4 (1.00 g, 7.6 mmol)and DMAP (50 mg, 0.4 mmol) in dry C
4
4
. Experimental
5 5
H N
ꢀ
ꢀ
(
5 mL) at 5e10 C. Stirring was continued for 30 min at 0e5 C and for
h at room temperature. The mixture was then diluted with ice and
water, and extracted with Et O. The extract was washed successively
with dil HCl, NaHCO solution and brine, dried (MgSO ), and con-
centrated in vacuo to give an oil (3.0 g). This was chromatographed
over SiO
(20 g). Elution with hexane/EtOAc (10:1) gave (ꢂ)-6 (1.62 g,
quant.) as a colorless oil, n
652 (m),1257 (s),1218 (m),1153 (m),1078 (m), 845 (m), 735 (m);
CDCl ): 1.38 (3H, s), 1.44 (3H, s), 1.80 (3H, d, J 6.8), 1.84 (3H, s), 3.79
1H, dd, J 7.2, 8.0), 4.09 (1H, dd, J 6.4, 8.0), 4.19 (2H, d, J 5.2), 4.36 (1H,
.1. General
1
2
D
Melting points are uncorrected values. Refractive indices (n )
3
4
were measured on an Atago DMT-1 refractometer. Optical rota-
tions were measured on a Jasco P-1020 polarimeter. IR spectra
2
1
were measured on a Jasco FT/IR-410 spectrometer. H NMR
18
D
¼1.4575;
nmax (film): 2987 (m), 1714 (s),
1
3
spectra (400 MHz, TMS at
NMR spectra (100 MHz, CDCl
d
¼0.00 as internal standard) and
C
1
(
(
d
H
3
at
d
¼77.0 as internal standard)
3
were recorded on a Jeol JNM-AL 400 spectrometer. GCeMS
were measured on Agilent Technologies 5975 inert XL. HRMS
were recorded on Jeol JMS-SX 102A or Varian 901-MS. Column
chromatography was carried out on Merck Kieselgel 60 Art
dt, J 11.2, 5.6), 6.90 (1H, q, J 7.2); GCeMS [column: HP-5MS, 5% phe-
nylmethylsiloxane, 30 mꢃ0.25 mm i.d.; carrier gas, He; press:
ꢀ
ꢀ
ꢀ
ꢀ
5
2.7 kPa, temp 50e160 C (þ10 C/min), then 160e220 C (þ4 C/
1
.07734.
þ
min)]: t
R
11.20 min (95.0%). MS (70 eV, EI): m/z: 200 (12) [M ꢁCH
2
],
þ
1
99 (100) [M ꢁCH
3
],114 (5),101 (35), 83 (69), 73 (8), 55 (22), 43 (27).
þ
HRMS calcd for C10
15
H O
4
[M ꢁCH
3
]: 199.0970, found: 199.0978.
4
.2. (R)-1,2-Ditigloyl-3-oleoylglycerol (1A)
4
.4.2. (R)-Isomer. Similarly, (S)-4 (1.00 g, 7.6 mmol) gave (R)-6
This was prepared from enantiomerically pure (S)-5 as pre-
17
20
3
17
21
(1.50 g, 98%) as a colorless oil, n
hexane); Its IR, H NMR and MS spectra were identical to those of
D
¼1.4592; [
a
]
D
þ17.7 (c 5.12,
viously reported, and obtained as an oil, n
.13, hexane); GCeMS [column: HP-5MS, 5% phenylmethylsiloxane,
D
¼1.4750; [
a
]
D
þ4.11 (c
1
4
3
(
ꢀ
(ꢂ)-6. GCeMS [same conditions as those for (ꢂ)-6]: t
R
11.22 min
]: 199.0970, found:
0 mꢃ0.25 mm i.d.; carrier gas, He; press: 52.8 kPa, temp 50
C
þ
ꢀ
ꢀ
(93.6%). HRMS calcd for C10
199.0976.
H
15
O
4
[M ꢁCH
3
2 min), then þ15 C/min, 300 C (60 min)]: t
R
24.98 min (92.1%). Its
1
13
IR, H and C NMR, and MS spectral data were identical to those
reported previously.3
4
.4.3. (S)-Isomer. Similarly, (R)-4 (1.00 g, 7.6 mmol) gave (S)-6
2
2
20
(1.53 g, quant.) as a colorless oil, n
D
¼1.4570; [
a]
D
ꢁ17.9 (c 5.15,
4
.3. 1,2-Diacetyl-3-oleoylglycerol (2A)
hexane). Its IR, NMR and MS spectra were identical to those of
(
ꢂ)-6. GCeMS [same conditions as those for (ꢂ)-6]: t
R
11.21 min
3
]: 199.0970, found:
þ
4
.3.1. (R)-Isomer. Acetyl chloride (785 mg, 10 mmol) was added
(95.7%). HRMS calcd for C10
199.0973.
H
15
O
4
[M ꢁCH
2
4
dropwise to a stirred and ice-cooled solution of (R)-5 {[
a
]
D
ꢁ2.94
(
c 3.57, pyridine), enantiomerically pure as determined by MTPA-
3
NMR analysis; 703 mg, 1.97 mmol} in dry pyridine (3 mL). The
mixture was left to stand for 3 d in a refrigerator, diluted with ice
4.5. 1-Tigloylglycerol (7)
and water, and extracted with Et
successively with dil HCl, NaHCO
MgSO ) and concentrated in vacuo. The residue (0.84 g) was
chromatographed over SiO (5 g). Elution with hexane/EtOAc
2
O. The extract was washed
4.5.1. Racemate. 80% Acetic acid [AcOH/H
2
O¼80:20 (v/v), 8 mL]
3
solution and brine, dried
was added to (ꢂ)-6 (1.60 g, 7.6 mmol), and the mixture was stirred
ꢀ
(
4
and heated at 130 C (bath temperature) for 10 min. The solution
2
was concentrated in vacuo, and the residue was diluted with tol-
uene. The solution was concentrated again in vacuo to remove
toluene, acetic acid and water to give 1.40 g (quant.) of (ꢂ)-7 as
2
0
(
[
(
1
1
15:1) gave (R)-2A (691 mg, 80%) as a colorless oil, n
D
¼1.4547;
max (film): 3005 (w), 2926 (s), 2854
m), 1749 (vs), 1653 (w), 1458 (m), 1371 (m), 1223 (s), 1169 (m),
098 (w), 1051 (m), 1017 (w); (CDCl ): 0.88 (3H, t, J 7.2),
.22e1.40 (20H, br, peaks at 1.27 and 1.30), 1.57e1.65 (2H, m),
.98e2.05 (4H, m), 2.08 (3H, s), 2.09 (3H, s), 2.32 (2H, t, J 7.6),
.13e4.18 (2H, m), 4.27e4.33 (2H, m), 5.23e5.26 (1H, m),
.32e5.40 (2H, m); (CDCl ) 14.1, 20.7, 20.9, 22.7, 24.9, 27.18,
7.23, 29.08, 29.11, 29.17, 29.3, 29.5, 29.7, 31.4, 34.0, 62.0, 62.3 69.1,
29.7, 130.0, 170.1, 170.5, 173.3; GCeMS [same conditions as those
2
4
a
]
D
þ1.33 (c 4.02, hexane);
n
1
9
a colorless and viscous oil, n
D
¼1.4742;
nmax (film): 3414 (m, br),
d
H
3
2948 (m), 1712 (s), 1651 (m), 1384 (m), 1269 (s), 1146 (m), 1079 (m),
735 (m), (CDCl ): 1.80 (3H, d, J 7.2), 1.84 (3H, s), 3.61 (1H, dd, J 6.0,
7.6), 3.71 (1H, dd, J 3.6, 7.2), 3.94e3.99 (1H, m), 4.10e4.30 (2H, m),
d
H
3
1
4
5
2
8 14 4
4.22 (2H, d, J 6.4), 6.90 (1H, q, J 7.2). HRMS calcd for C H O :
174.0892, found: 174.0898.
d
C
3
1
4.5.2. (R)-Isomer. Similarly, (R)-6 (1.48 g, 7.3 mmol) and 80% acetic
þ
ꢀ
for 1A]: t
R
19.38 min (83.1%); MS (70 eV, EI): m/z: 440 (<1)[M ],
acid (17 mL) was stirred and heated at 50 C for 1 h. The resulting

K. Mori / Tetrahedron 70 (2014) 5752e5762
5759
ꢀ
homogeneous solution was concentrated in vacuo at <60 C. The
4.8. (±)-1-Acetyl-2,3-acetoneglycerol (9)
A solution of acetyl chloride (1.30 g, 17 mmol) in dry C
6 6
residue was dissolved in C H and concentrated in vacuo. This
operation was repeated three times to remove acetic acid and water
6
H
6
(5 mL)
completely, yielding (R)-7 (1.30 g, quant.) as a colorless oil,
was added to a stirred and ice-cooled solution of (ꢂ)-4 (1.53 g,
17
20
1
n
D
¼1.4764; [
a
]
D
þ2.73 (c 3.64, CHCl
3
); Its IR and H NMR spectra
11.6 mmol) and DMAP (25 mg) in dry C N (5 mL). The mixture
5 5
H
were identical to those of (ꢂ)-7. (R)-7 was enantiomerically pure as
was stirred for 1 h at room temperature, and worked up as de-
3
analyzed by MTPA/NMR method. HRMS calcd for C
8
H
14
O
4
:
scribed for (ꢂ)-6 to give 2.34 g (quant.) of crude (ꢂ)-9 as a colorless
1
9
174.0892, found: 174.0899.
oil, n
1
D
¼1.4332;
nmax (film): 2988 (m), 1746 (s), 1372 (m), 1233 (s),
H 3
159 (w), 1055 (m), 984 (w), 683 (m); d (CDCl ): 1.37 (3H, s), 1.44
4
.5.3. (S)-Isomer. Similarly, (S)-6 (1.43 g, 7.1 mmol) yielded (S)-7
(3H, s), 2.09 (3H, s), 3.70e3.57 (1H, m), 4.04e4.10 (2H, m),
2
2
22
1
(
1.29 g, quant.) as a colorless oil, n
D
¼1.4710; [
a
]
D
ꢁ2.28 (c 4.50,
4.15e4.19 (1H, m), 4.30e4.34 (1H, m). These IR and H NMR data
); Its IR and 1H NMR spectra were identical with those of
are in good accord with those of (S)-9. GCeMS [same conditions
14
CHCl
3
(
[
ꢂ)-7. (S)-7 was of 90% ee as analyzed by MTPA/NMR method
signal area of 4.60e4.65 (dd)/
4.70e4.75 (dd)¼5:95]. HRMS
: 174.0892, found: 174.0897.
as those used for (ꢂ)-6]: t
R
6.69 min (99.7%); MS (70 eV,EI): m/z:
3
], 101 (29), 72 (14), 57 (9), 43 (97).
þ
d
d
159 (100) [M ꢁCH
8 14 4
calcd for C H O
4.9. (±)-1-Acetylglycerol (10)
4
.6. 1,3-Ditigloylglycerol (8)
A mixture of (ꢂ)-9 (1.80 g, 10.3 mmol) and 80% acetic acid
ꢀ
(
1
10 mL) was stirred and heated at 130 C (bath temperature) for
2
Triethylamine (950 mg, 9.4 mmol) and (n-Bu) SnO (2.01 g,
.07 mmol) were added to
0 min. The resulting homogeneous solution was concentrated in
vacuo. The residue was mixed with toluene, and concentrated again
in vacuo to remove toluene, acetic acid and water. The remaining oil
8
8
a
solution of (ꢂ)-7 (1.40 g,
.07 mmol) in dry CH Cl (70 mL) under argon. The suspension
2
2
was stirred for 15 min at room temperature. Subsequently,
a solution of tigloyl chloride (971 mg, 8.2 mmol) in dry CH Cl
4 mL) was added dropwise to the ice-cooled and stirred sus-
(
ꢂ)-10 (1.35 g, 97%) was used in the next step without further
2
2
15
purification, n
D
¼1.4502;
nmax (film): 3394 (m, br), 2952 (w), 1737
(
(
d
s), 1376 (m), 1247 (s), 1119 (w), 1046 (s), 981 (w), 933 (w), 848 (w);
(CDCl ): 2.11 (3H, s), 3.57e3.72 (2H, m), 3.50e3.70 (2H, br),
.90e3.98 (1H, m), 4.10e4.20 (2H, m). These IR and H NMR data
ꢀ
pension at 10e15 C. The milky white mixture was stirred for
.5 h at room temperature, and filtered through Celite. The
H
3
4
1
3
Celite layer was washed with EtOAc, and the combined filtrate
and washings were concentrated in vacuo. The residue was
15
are in good accord with those of (S)-10.
chromatographed over SiO
20:1) gave 1,2,3-tritigloylglycerol (228 mg). Further elution
with hexane/EtOAc (20:1 to 10:1) gave 8 (1.44 g, 70%) as a col-
2
(20 g). Elution with hexane/EtOAc
4
.10. 1,3-Diacetylglycerol (11) contaminated with (±)-1,2-
(
diacetylglycerol [(±)-12]
orless oil, n1
s), 1651 (m), 1442 (m), 1382 (m), 1344 (m), 1261 (s), 1143 (s),
079 (s), 735 (s); (CDCl ): 1.80 (6H, d, J 7.2), 1.84 (6H, s), 2.74
1H, s, br), 4.14e4.20 (1H, m), 4.24 (4H, dd, J 6.4, 7.0), 6.90 (2H,
q, J 7.2); (CDCl ): 12.0, 14.4, 65.3, 68.5, 128.0, 138.3, 168.1;
8
¼1.4858;
nmax (film): 3480 (m, br), 2954 (m), 1713
D
2
Triethylamine (1.01 g, 10 mmol) and (n-Bu) SnO(2.42 g,
(
9
.7 mmol) were added to a solution of (ꢂ)-10 (1.32 g, 9.7 mmol) in
dry CH Cl (70 mL) under argon. The suspension was stirred for
5 min at room temperature. A solution of acetyl chloride (790 mg,
0.1 mmol) in dry CH Cl (4 mL) was added dropwise to the stirred
1
d
H
3
2
2
(
1
1
d
C
3
2
2
GCeMS [same conditions as those used for 6]: t
R
16.34 min
and ice-cooled suspension. Stirring was continued for 30 min at
þ
(
(
98.8%); MS (70 eV, EI): m/z: 238 (7) [M ꢁH
2
O], 157 (12), 156
12), 143 (11), 83 (100), 55 (31). HRMS calcd for C13
ꢀ
5e10 C and for 2 h at room temperature. The mixture was filtered
H
20
O
5
:
through Celite. The Celite layer was washed with EtOAc, and the
combined filtrate and washings were concentrated in vacuo. The
2
56.1311, found: 256.1310.
residue (1.8 g) was chromatographed over SiO
2
(25 g). Elution with
4
.7. 1,3-Ditigloyl-2-oleoylglycerol (1B)
hexane/EtOAc (2:1) gave 1.48 g (86%) of a 65:35 mixture of 11 and
2
0
(
ꢂ)-12 as a colorless oil, n
(m), 1741 (s), 1439 (m), 1374 (s), 1233 (s), 1048 (s), 607 (m);
(CDCl ): 2.11 (6H, s), 2.94 (1H, br), 3.74 (0.7H, d, J 4.8), 4.08e4.25
(4H, m), 5.06e5.09 (0.3H, m); GCeMS [same conditions as those
used for 6]: t
D
¼1.4382;
nmax (film): 3463 (m, br), 2959
A solution of oleoyl chloride (2.00 g, 6.6 mmol) in dry C
6
H
6
d
H
(
(
5 mL) was added dropwise to a stirred and ice-cooled solution of 8
1.41 g, 5.5 mmol) and DMAP (20 mg) in dry C
3
5
H
5
N (6 mL) at
ꢀ
ꢀ
5
e10 C. The mixture was stirred for 15 min at 5e10 C, and for 1 h
R
8.74 min (64.9%, 11), 8.78 min [35.1%, (ꢂ)-12]; MS
at room temperature. It was then diluted with ice and water, and
extracted with Et O. The extract was washed successively with dil
HCl, NaHCO solution and brine, dried (MgSO ), and concentrated
in vacuo to give an oily residue (3.62 g). This was chromatographed
over SiO (30 g). Elution with hexane/EtOAc (20:1) gave 2.20 g
(70 eV, EI): m/z: 103 (59), 43 (100) for 11; 103 (41), 43 (100) for
þ
2
(ꢂ)-12. HRMS calcd for C
7
H
11
O
4
[M ꢁOH]: 159.0657, found:
3
4
159.0666.
2
4.11. 1,3-Diacetyl-2-oleoylglycerol (2B) contaminated with
1,2-diacetyl-3-oleoylglycerol [(±)-2A]
1
9
(
(
(
6
(
4
(
2
77%) of 1B as a slightly yellowish oil, n
s), 2855 (s), 1744 (s), 1718 (vs), 1653 (m), 1461 (m), 1380 (m), 1343
w), 1254 (s), 1135 (m), 1079 (m), 733 (m); (CDCl ): 0.88 (3H, t, J
.8), 1.20e1.40 (20H, peaks at 1.27 and 1.29), 1.55e1.65 (2H, m), 1.79
6H, d, J 7.2), 1.82 (6H, s), 1.95e2.08 (4H, m), 2.32 (2H, t, J 7.6),
.22e4.37 (4H, m), 5.30e5.40 (3H, m), 6.82e6.90 (2H, m);
CDCl ): 12.0, 14.1, 14.4, 22.7, 24.9, 25.6, 27.13, 27.18, 29.0, 29.1, 29.2,
9.3, 29.5, 29.68, 29.73, 31.9, 34.2, 62.5, 68.9, 128.0, 129.7, 130.0,
D
¼1.4770;
nmax (film): 2925
d
H
3
6 6
A solution of oleoyl chloride (0.85 g, 2.8 mmol) in dry C H
(3 mL) was added dropwise to a stirred and ice-cooled solution of
the above mixture of 11 and (ꢂ)-12 (440 mg, 2.5 mmol) and DMAP
ꢀ
d
C
(10 mg) in dry C
5
H
5
N (3 mL) at 5e10 C. The mixture was stirred at
ꢀ
3
5e10 C for 15 min and then for 1 h at room temperature. It was
then diluted with ice and water, and extracted with Et
tract was washed successively with dil HCl, NaHCO solution and
brine, dried (MgSO ), and concentrated in vacuo to give a residual
oil (1.58 g). This was chromatographed over SiO (20 g). Elution
with hexane/EtOAc (20:1) gave 0.95 g (87%) of a 2:1 mixture of 2B
2
O. The ex-
138.2, 167.4, 172.9; GCeMS [same conditions as those used for 1A]:
3
þ
t
[
(
R
24.80 min (88.2%); MS (70 eV, EI): m/z: 520 (<1) [M ], 420 (16)
4
þ
þ
M ꢁtiglic acid (TA)], 239 (47) [M -oleic acid (OA)], 157 (12), 83
100), 55 (22). HRMS calcd for C31 : 520.3764, found:
20.3754.
2
52 6
H O
2
0
5
and (ꢂ)-2A as an oil, n
D
¼1.4558;
nmax (film): 3005 (w), 2925 (s),

5760
K. Mori / Tetrahedron 70 (2014) 5752e5762
2
854 (s), 1749 (s), 1459 (m), 1369 (m), 1224 (s), 1167 (m), 1100 (w),
hexane/EtOAc (3:2), and transferred on a SiO
tion with hexane/EtOAc (3:2) gave 2.46 g (61%) of a mixture of 11
and (ꢂ)-12, max (film):3462 (m), 2961 (m), 1740 (s), 1436 (m), 1374
(s), 1236 (s), 959 (m), 607 (m); GCeMS [same conditions as those
2
(25 g) column. Elu-
1
1051 (m); Its H NMR spectrum was almost identical to that of 2A.
13
The C NMR spectrum of 2B was different from that of 2A
reflecting its symmetrical structure: (1) Only two signals for
n
RCOOCH
signals for C]O could be observed at
same conditions as those used for 1A]: t
2
e could be observed at
d
62.3 and 68.8 and (2) Only two
for 6]. t
R
8.86 min (63.4%, 11), 8.91 min [28.1%, (ꢂ)-12]. MS of 11
þ
d
170.5 and 173.0. GCeMS
(70 eV, EI): m/z: 158 (<1) [M ꢁH
2
O], 103 (52), 86 (6), 74 (8), 43
þ
[
R
19.35 min (61.4%, 2B),
(100); MS of (ꢂ)-12 (70 eV, EI): m/z: 158 (<1) [M ꢁH
2
O], 145 (5),
þ
1
3
9.39 min [28.8%, (ꢂ)-2A]; MS of 2B (70 eV, EI): m/z: 440 (<1)[M ],
103 (38), 86 (12), 74 (5), 43 (100).
þ
80 (7) [M ꢁAcOH], 265 (67), 264 (57), 159 (100), 43 (54); MS of
þ
þ
(
(
[
ꢂ)-2A (70 eV, EI); m/z: 440 (<1)[M ], 380 (7) [M ꢁAcOH], 265
4.16. 1-Acetyl-3-oleoylglycerol (16)
þ
26), 264 (31), 159 (100), 43 (44). HRMS calcd for C25
H
44
O
6
Na
þ
MþNa] : 463.3030, found: 463.3030.
4.16.1. (S)-Isomer. Triethylamine (505 mg,
Bu) SnO (1.230 g, 5 mmol) were added to a solution of (S)-5
(1.78 g, 5 mmol) in dry CH Cl (70 mL) under argon. The sus-
pension was stirred for 10 min at room temperature. Then a so-
lution of acetyl chloride (393 mg, 5 mmol) in dry CH Cl (10 mL)
5 mmol) and (n-
2
4
.12. 1,3-Ditigloyloxyacetone (14)
2
2
Tigloyl chloride (1.25 g, 10.5 mmol) in dry C
H
6 6
(2 mL) was
2
2
added to a stirred and ice-cooled solution of 13 (0.45 g, 2.5 mmol)
was added dropwise over 10 min to the stirred and ice-cooled
suspension at 10e15 C. Subsequently, the milky white mixture
ꢀ
ꢀ
in dry C
5
5
H N (2 mL) at 0e5 C. The mixture was stirred for 2 h at
room temperature to precipitate solid C
luted with ice-water, and extracted with Et
washed successively with dil HCl, NaHCO solution and brine, dried
MgSO ), and concentrated in vacuo. The residue (1.073 g) was
chromatographed over SiO (15 g). Elution with hexane/EtOAc
20:1e10:1) gave 580 mg (91%) of 14 as a colorless solid. Re-
5
H
5
N$HCl. It was then di-
was stirred for 1.5 h at room temperature. The mixture was fil-
tered through Celite. The Celite layer was washed with EtOAc, and
the combined filtrate and washings were concentrated in vacuo.
2
O. The extract was
3
(
4
2
The residue (2.2 g) was chromatographed over SiO (30 g). Elution
2
with hexane/EtOAc (20:1e10:1) gave 387 mg of triacylglycerol.
Further elution with hexane/EtOAc (5:1) furnished (S)-16 (1.44 g,
(
ꢀ
18
19
crystallization from hexane/EtOAc gave rhombs, mp 46.0e46.5 C;
max (Nujol): 1745 (s), 1712 (s), 1650 (s), 1269 (s), 1149 (s), 733 (s),
CDCl ): 1.83 (6H, d, J 6.8), 1.87 (6H, s), 3.91 (4H, s), 6.98 (1H, q-like, J
(CDCl ): 12.0, 14.6, 66.6, 127.6, 139.3, 167.1, 199.0; GCeMS
73%) as a colorless oil, n
max (film): 3471 (m, br), 3005 (m), 2925 (s), 2854 (4), 1743 (s),
1654 (w), 1459 (m), 1377 (m), 1235 (s), 1177 (m), 1119 (w), 1047
(m), 944 (w), 723 (w); (CDCl ): 0.88 (3H, t, J 6.8), 1.20e1.40
D
¼1.4612. [
a
]
D
ꢁ0.81 (c 5.26, hexane);
n
d
H
n
(
3
6
.8);
d
C
3
d
H
3
[
(
8
same conditions as those used for 6]: t
70 eV, EI): m/z: 254 (<1)[M ], 154 (13) [M etiglic acid], 141 (51),
3 (100), 55 (42). HRMS calcd for C13
R
16.29 min (97.6%); MS
(20H, br, peaks at 1.27 and 1.30), 1.60e1.68 (2H, m), 1.98e2.08 (4H,
m), 2.11 (3H, s), 2.35 (2H, t, J 7.6), 2.47e2.50 (1H, br), 4.05e4.25
(5H, m), 5.30e5.40 (2H, m); GCeMS [same conditions as those
þ
þ
18
H O5: 254.1154, found:
2
54.1151.
used for 1A]: t
R
19.26 min (86.7%); MS (70 eV, EI): m/z: 380 (7)
þ
[
M ꢁH
2
O], 265 (32), 207 (12), 129 (13), 117 (100), 98 (28), 81 (27),
4
.13. 1,3-Ditigloylglycerol (8) by reduction of 14
69 (28), 67 (27), 55 (38), 43 (69). HRMS calcd for
þ
C
23
H
42
O
5
Na :421.2924, found: 421.2926.
A solution of 14 (374 mg, 1.5 mmol) in dry THF (3 mL) was added
dropwise to a solution of Zn(BH
4
)
2
in dry THF [prepared by the
4.16.2. (R)-Isomer. Similarly, 1.78 g (5 mmol) of (R)-5 gave 1.41 g
18
15
1
addition of a solution of ZnCl (68 mg, 0.5 mmol) in dry THF (2 mL)
2
(71%) of (R)-16, n
NMR and MS spectra were identical to those of (S)-16. GCeMS
D
¼1.4628; [
a
]
D
þ0.64 (c 5.06, hexane). Its IR, H
to stirred NaBH
4
(38 mg, 1.0 mmol)] under ice-cooling and stirring.
ꢀ
After stirring for 20 min at 5e10 C, the reaction was quenched by
the addition of acetic acid (0.1 mL). The mixture was concentrated
in vacuo. The residue was diluted with hexane/EtOAc (10:1), and
[same conditions as those used for 1A]: t
R
19.09 min (77.4%). HRMS
þ
calcd for C23
42
H O
5
Na : 421.2924, found: 421.2926.
chromatographed over SiO
gave 377 mg (quant.) of 14 as a colorless oil, n
NMR and MS spectra were identical with those of 8 described in 4.6
2
(5 g). Elution with hexane/EtOAc (10:1)
4.17. 1-Acetyl-2-tigloyl-3-oleoylglycerol (3A)
2
0
1
D
¼1.4858. Its IR, H
4.17.1. (S)-Isomer. A solution of tigloyl chloride (534 mg, 4.5 mmol)
(
1
vide supra). GCeMS [same conditions as those used for 6]: t
6.61 min (94.6%).
R
2 2
in dry CH Cl (3 mL) was added dropwise to a stirred and ice-cooled
solution of (S)-16 (1.36 g, 3.4 mmol) and DMAP (50 mg) in dry
ꢀ
C
5
H
5
N (3 mL). The mixture was stirred for 30 min at 5e15 C and for
4
.14. 1,3-Diacetoxyacetone (15)
2 h at room temperature until white C
was then diluted with ice and water, and extracted with Et
extract was washed successively with dil HCl, NaHCO solution and
brine, dried (MgSO ), and concentrated in vacuo. The residue
1.61 g) was chromatographed over SiO (15 g). Elution with hex-
ane/EtOAc (20:1) gave (S)-3A (1.17 g, 71%) as a slightly yellowish oil,
5
H
5
N$HCl separated out. It
2
O. The
15
This was prepared according to Suemune et al. as needles, mp
3
ꢀ
4
6 C, in 77% yield based on 13.
4
(
2
4
.15. 1,3-Diacetylglycerol (11) contaminated with (±)-12 by
2
0
23
reduction of 15
n
2
D
¼1.4660; [
920 (s), 2855 (s), 1748 (s), 1717 (s), 1652 (m), 1458 (m), 1380 (m),
1368 (m),1229 (s),1153 (m),1134 (m),1075 (m),1049 (m),1020 (m),
733 (m); (CDCl ): 0.88 (3H, t, J 6.8), 1.22e1.41 (20H, br, peaks at
a
]
D
þ0.85 (c 5.04, hexane);
nmax (film): 3004 (m),
NaBH
stirring with EtOAc for 3 h at room temperature, collected on a glass
filter, washed with Et
O, and dried to remove alkaline impurities.16
A solution of ZnCl (612 mg, 4.5 mmol) in dry THF (8 mL) was added
to a stirred and ice-cooled suspension of NaBH (342 mg, 9 mmol)
in dry THF (12 mL). A solution of 15 (3.00 g, 17 mmol) in dry THF
4
used in this experiment was washed thoroughly by
d
H
3
2
1.27 and 1.30), 1.60 (2H, t-like, J 7.2), 1.80 (3H, d, J 6.8), 1.83 (3H, s),
1.98e2.10 (4H, m), 2.07 (3H, s), 2.31 (2H, t, J 7.6), 4.15e4.25 (2H, m),
2
4
4.28e4.38 (2H, m), 5.30e5.40 (3H, m), 6.80e7.00 (1H, m);
d
C
(CDCl ): 11.9, 14.0, 14.4, 14.8, 20.6, 22.6, 24.8, 25.5, 27.09, 27.13,
3
(
10 mL) was added dropwise to the stirred and ice-cooled solution
28.99, 29.02, 29.2, 29.5, 29.62, 29.69, 31.8, 33.9, 62.0, 62.2, 69.0,
128.0, 129.6, 129.9, 138.3, 166.9, 170.5, 173.2; GCeMS [same condi-
ꢀ
of Zn(BH
4
)
2
. Stirring was continued for 20 min at 0e5 C. The re-
action was quenched by the addition of acetic acid (1 mL), and the
mixture was concentrated in vacuo. The residue was triturated with
tions as those used for 1A]: t
[4.4%, (S)-3B], 21.78 min [16.4%, (R)-3C]; MS of (S)-3A (70 eV, EI): m/
R
21.62 min [69.8%, (S)-3A], 21.68 min

K. Mori / Tetrahedron 70 (2014) 5752e5762
5761
þ
þ
þ
þ
þ
þ
z 480 (<1) [M ], 420 (4) [M ꢁAcOH], 380 (10) [M ꢁtiglic acid], 264
(4) [M eAcOH], 380 (10)[M etiglic acid], 264 (14), 199 (52) [M -
þ
þ
(
14), 199 (52) [M ꢁoleic acid]. 83 (100), 55 (23), 43 (12). HRMS
oleic aid], 83 (100), 55 (23), 43 (12). HRMS calcd for C28
503.3343, found 503.3343.
H
48
O
6
Na :
þ
calcd for C28
H
48
O
6
Na : 503.3343, found: 503.3343.
4
.17.2. (R)-Isomer. Similarly, (R)-16 (1.19 g, 3.3 mmol) gave (R)-3A
4.19.2. (R)-Isomer. Similarly, (R)-17 (1.05 g, 4.9 mmol) afforded (R)-
2
0
23
17
20
(
1.11 g, 78%) as an oil, n
IR, NMR and MS spectra were identical with those of (S)-3A.
GCeMS [same conditions as those used for 1A]: t 21.55 min [79.6%,
R)-3A], 21.63 min [3.2%, (R)-3B], 21.73 min [7.7%, (S)-3C]. HRMS
D
¼1.4674; [
a]
D
ꢁ0.60 (c 5.06, hexane). Its
3B (1.91 g, 82%) as a slightly yellowish oil, n
D
¼1.4674; [
5.20, hexane). Its IR, H NMR and MS spectra were identical with
those of (S)-17. GCeMS [same conditions as those used for 1A]; t
a
]
D
þ4.44 (c
1
R
R
(
21.68 min [64.0%, (R)-3B], 21.77 min [28.6%, (R)-3C]. HRMS calcd for
þ
þ
calcd for C28
H
48
O
6
Na : 503.3343, found: 503.3344.
C
28
H
48
O
6
Na : 503.3343, found: 503.3343.
4
.18. 1-Acetyl-3-tigloylglycerol (17)
4.20. 1-Oleoyl-3-tigloylglycerol (18)
4
Bu)
.18.1. (S)-Isomer. Triethylamine (404 mg,
4
mmol) and (n-
SnO (996 mg, 4 mmol) was added to a solution of (S)-7
Cl (40 mL) under argon. The sus-
pension was stirred for 15 min at room temperature. A solution of
4.20.1. (R)-Isomer. Triethylamine (364 mg, 3.6 mmol) and (n-
2
Bu)
(1.26 g, 3.5 mmol) in dry CH
pension was stirred for 10 min at room temperature. A solution of
2
SnO (871 mg, 3.5 mmol) were added to a solution of (S)-5
(
702 mg, 4 mmol) in dry CH
2
2
2
2
Cl (50 mL) under argon. The sus-
acetyl chloride (315 mg, 4 mmol) in dry CH
2
Cl
2
(3 mL) was added
tigloyl chloride (427 mg, 3.6 mmol) in dry CH
dropwise to the stirred and ice-cooled suspension at 10e15 C. The
milky white mixture was stirred for 30 min at 5e10 C, and then for
3 h at room temperature. The mixture was then filtered through
Celite. The Celite layer was washed with EtOAc, and the combined
filtrate and washings were concentrated in vacuo to give an oily
2
Cl
2
(4 mL) was added
ꢀ
ꢀ
dropwise to the stirred and ice-cooled suspension at 10e15 C.
The milky white mixture was stirred for 3 h at room temperature,
and filtered through Celite. The Celite layer was washed with
EtOAc, and the combined filtrate and washings were concentrated
ꢀ
in vacuo. The residue (1.1 g) was chromatographed over SiO
20 g). Elution with hexane/EtOAc (20:1) gave 80 mg of tri-
acylglycerol. Further solution with hexane/EtOAc (4:1) afforded
2
(
2
residue (2.52 g). This was chromatographed over SiO (20 g). Elu-
tion with hexane/EtOAc (50:1e20:1) gave 157 mg of impurities.
Further elution with hexane/EtOAc (10:1) gave 1.54 g (99%) of (R)-
2
5
26
6
4
1
(
2
5
6
09 mg (70%) of (S)-17 as a colorless oil, n
.49, Et O); max (film): 3472 (m, br), 2957 (m), 1742 (s), 1714 (s),
651 (m), 1442 (m), 1375 (m), 1254 (s), 1146 (m), 1080 (m), 1047
m), 946 (w), 736 (m); (CDCl ): 1.81 (3H, d, J 6.8), 1.85 (3H, s),
.11 (3H, s), 2.75 (1H, br, s), 4.10e4.20 (3H, m), 4.24 (2H, t-like J
D
¼1.4650; [
a
]
D
ꢁ2.20 (c
1
9
20
2
n
18 as a colorless oil, n
D
¼1.4722; [
a
]
D
þ1.14 (c 4.24, hexane);
n
max
(film): 3852 (m, br), 3004 (m), 2925 (s), 2854 (s), 1741 (s), 1715 (s),
d
H
3
1652 (m), 1458 (m), 1380 (m), 1266 (s), 1145 (s), 1080 (m), 734 (m);
d (CDCl ): 0.88 (3H, t, J 6.8), 1.20e1.40 (20H, br, peaks at 1.27 and
H 3
1.36), 1.60e1.70 (2H, m), 1.80 (3H, d, J 6.8), 1.84 (3H, s), 1.96e2.10
(4H, m), 2.35 (2H, t, J 7.6), 2.60 (1H, br), 4.10e4.30 (5H, m),
5.32e5.41 (2H, m), 6.86 (1H, q, J 6.8); GCeMS [same conditions as
.6), 6.90 (1H, q, J 6.8); GCeMS [same conditions as those used for
þ
þ
]; t
R
13.04 min (88.1%); MS (70 eV, EI): m/z: 216 (<1) [M ], 198
þ
þ
(
9), [M ꢁH
2
O], 156 (8) [M ꢁAcOH], 143 (7), 117 (10) [M ꢁtiglic
acid], 99 (13), 83 (100), 55 (36), 43 (32). HRMS calcd for C10
H
16
O
5
:
those used for 1A]; t
R
21.10 min (99.1%); GCeMS (70 eV, EI): m/z 438
þ
þ
þ
216.0998, found 216.0992.
(<1) [M ], 420 (4) [M ꢁH
2
O], 338 (3) [M ꢁtiglic acid], 207 (5), 157
þ
(36), 83 (100), 55 (23), HRMS calcd for C26
H
46
O
5
Na : 461.3237,
4
.18.2. (R)-Isomer. Similarly, (R)-7 (1.40 g, 8 mmol) gave (R)-17
found: 461.3237.
21
23
(
1.24 g, 71%) as a colorless oil, n
D
¼1.4638; [
a
]
D
þ2.33 (c 4.18, Et
2
O);
GCeMS [same conditions as those used for 6]; t
Its IR, H NMR and MS spectra were identical with those of (S)-17,
HRMS calcd for C10 : 216.0998, found: 216.1008.
R
13.02 min (98.0%).
4.20.2. (S)-Isomer. Similarly, (R)-6 (1.20 g, 3.4 mmol) gave (S)-18
(1.49 g, quant.) as a colorless oil, n
hexane); GCeMS [same conditions as those used for 1A]; t
1
17
18
D
¼1.4733; [
a
]
D
ꢁ1.24 (c 5.07,
H
16
O
5
R
1
21.11 min (98.3%); Its IR, H NMR and MS spectra were identical
þ
4
.19. 1-Acetyl-2-oleoyl-3-tigloylglycerol (3B)
with those of (R)-18. HRMS calcd for C26H O Na : 461.3237,
46 5
found: 461.3237.
4
.19.1. (S)-Isomer. A solution of oleoyl chloride (900 mg, 3 mmol)
(3 mL) was added dropwise to a stirred and ice-cooled
solution of (S)-17 (450 mg, 2.1 mmol) and DMAP (10 mg) in dry
in dry C
6
H
6
4.21. 1-Oleoyl-2-acetyl-3-tigloylglycerol (3C)
ꢀ
ꢀ
C
5
H
5
N (3 mL) at 5e10 C. The mixture was stirred at 5e10 C for
0 min and 1 h at room temperature. It was then diluted with ice
O. The extract was washed
solution and brine, dried
), and concentrated in vacuo to give an oily residue
1.28 g). This was chromatographed over SiO (7 g). Elution with
4.21.1. (R)-Isomer. A solution of acetyl chloride (471 mg, 6 mmol)
in dry C (2 mL) was added dropwise to a stirred and ice-
3
6
H
6
and water, and extracted with Et
successively with dil HCl, NaHCO
2
cooled solution of (R)-18 (1.38 g, 3.1 mmol) and DMAP (50 mg)
ꢀ
3
in dry C
5
H
5
N (2 mL) and dry C
6
H
6
(2 mL) at 10e15 C. The
ꢀ
(
(
MgSO
4
mixture was stirred for 30 min at 10e15 C, and then for 3 h at
2
room temperature. It was diluted with ice and water, and
hexane/EtOAc gave 907 mg (91%) of (S)-3B as a colorless to slightly
extracted with Et
dil HCl, NaHCO solution and brine, dried (MgSO
trated in vacuo. The residual oil (2.00 g) was chromatographed
over SiO (5 g). Elution with hexane/EtOAc (20:1) gave 1.26 g
(83%) of (R)-3C as a colorless oil, n
hexane); max (film): 3004 (m), 2925 (s), 2855 (s), 1748 (s), 1718
(s), 1653 (m), 1459 (m), 1372 (m), 1258 (s), 1230 (s), 1153 (m),
1136 (m), 1079 (m), 1018 (w), 959 (w), 733 (m); (CDCl ): 0.88
2
O. The extract was washed successively with
yellowish oil, n2
005 (w), 2926 (s), 2855 (s), 1748 (s), 1718 (s), 1652 (w), 1458 (m),
368 (m), 1231 (s), 1155 (s), 1080 (m), 1051 (m), 733 (m);
CDCl ): 0.88 (3H, t, J 7.2), 1.22e1.41 (20H, br, peaks at 1.27 and
.30), 1.58e1.68 (2H, m), 1.80 (3H, d, J 6.8), 1.82 (3H, s), 2.00e2.10
4H, m), 2.07 (3H, s), 2.33 (2H, t, J 7.2), 4.15e4.25 (2H, m),
3
¼1.4665; [
a
]
24
ꢁ4.52 (c 5.80, hexane)
n
max (film):
), and concen-
D
D
3
4
3
1
d
H
2
2
2
24
(
3
D
¼1.4653; [
a
]
D
þ3.93 (c 4.14,
1
(
n
4
.29e4.35 (2H, m), 5.30e5.42 (3H, m), 6.86 (1H, q, J 6.8);
): 12.0, 14.1, 14.4, 20.7, 22.6, 24.9, 25.6, 27.12, 27.18, 29.0,
9.06, 29.14, 29.28, 29.48, 29.66, 29.72, 31.9, 34.2, 62.3, 62.5, 68.8,
d
C
d
H
3
(
CDCl
3
(3H, t, J 7.2), 1.20e1.40 (20H, br, peaks at 1.27 and 1.30), 1.61 (2H,
t-like, J 7.2), 1.80 (3H, d, J 6.8), 1.83 (3H, s), 1.96e2.08 (4H, m), 2.08
(3H, s), 2.32 (2H, t, J 7.6), 4.15e4.25 (2H, m), 4.30e4.36 (2H, m),
2
128.0, 129.7, 130.0, 138.2, 167.4, 170.5, 172.9; GCeMS [same con-
ditions as those used for 1A]; t
R
21.72 min [62.6% (S)-3B],
5.28e5.40 (3H, m), 6.86 (1H, q, J 6.8);
14.4, 20.8, 22.6, 24.8, 25.6, 27.09, 27.14, 29.00, 29.04, 29.3, 29.5,
C 3
d (CDCl ): 11.9, 14.0, 14.1,
þ
21.80 min [26.6%, (S)-3C]; MS (70 eV, EI): m/z: 480 (<1) [M ], 420

5762
K. Mori / Tetrahedron 70 (2014) 5752e5762
2
9.6, 29.7, 31.8, 34.0, 62.3, 62.4, 69.1, 128.0, 129.9, 130.1, 138.2,
Acknowledgements
167.3, 170.0, 173.3; GCeMS [same conditions as those used for
1
A]; t
R
21.28 min [13.7%, (S)-3A], 21.37 min [4.9%, (R)-3B],
I thank Mr. M. Kimura (President, Toyo Gosei Co., Ltd.) and Mr. Y.
Kimura (CEO, Toyo Gosei Co., Ltd.) for their support. My thanks are
due to Dr. Joanne Y. Yew (Temasek Life Sciences Laboratory, Na-
tional University of Singapore) for her suggestion to undertake the
present work. Comments by Prof. Dr. Wittko Francke (Universit a€ t
þ
21.53 min [71.5%, (R)-3C]; MS (70 eV, EI): m/z: 480 (<1) [M ], 420
þ
þ
(
(
5) [M ꢁAcOH], 380 (9) [M ꢁtiglic acid], 264 (11), 199 (50), 83
þ
100), 55 (18). HRMS calcd for C28
H
48
O
6
Na 503.3343, found:
5
03.3343.
Hamburg) on the MS analysis of 1A gave me the driving force to
carry out the present work. Dr. T. Tashiro (Niigata University of
Pharmacy and Applied Life Sciences) prepared the Figures and
Schemes. Mr. Y. Shikichi (Toyo Gosei Co., Ltd) is thanked for NMR
and GCeMS analyses. Drs. T. Nakamura and Y. Hongo (both at
RIKEN) kindly executed the HRMS analysis. Dr. K. Kikuzato (RIKEN)
is thanked for his help in HRMS analysis HPLC analysis was kindly
executed by Drs. H. Watanabe and Y. Ohkubo (T. Hasegawa Co., Ltd).
4
(
4
.21.2. (S)-Isomer. Similarly, (S)-18 (1.33 g, 30 mmol) afforded
S)-3C (1.06 g, 73%) as a colorless oil, n2
0
¼1.4668; [
a
]
22
ꢁ3.79 (c
D
D
.63, hexane); GCeMS [same conditions as those used for 1A]; t
R
21.51 min [5.7%, (R)-3A], 21.61 min [2.9% (S)-3B], 21.77 min
1
[
74.9%, (S)-3C]. Its IR, H NMR and MS spectra were identical with
þ
those of (R)-3C. HRMS calcd for C28
5
H
48
O
6
Na : 503.3343, found:
03.3343.
References and notes
4
.22. GCeMS co-injection experiments
1
. Shikichi, Y.; Shankar, S.; Yew, J. Y.; Mori, K. Biosci. Biotechnol. Biochem 2013, 77,
1931e1938.
4
1
.22.1. Co-injection of (R)-1A with 1B. A 1:2 mixture of (R)-1A and
B in Et O was analyzed by GCeMS under the conditions used for
24.56 min for (R)-1A and 24.80 min for 1B
see Fig. 6a]. They showed almost the same MS spectra.
2. Fischer, H. O. L.; Baer, E. Chem. Rev. 1941, 29, 287e316.
2
3. Mori, K. Tetrahedron 2012, 68, 8441e8449.
the analysis of (R)-1A: t
[
R
4. Chen, C.-Y.; Han, W.-B.; Chen, H.-J.; Wu, Y.-K.; Gao, P. Eur. J. Org. Chem. 2013,
4311e4318.
5
6
. Chen, H.-J.; Chen, C.-Y.; Gao, P.; Wu, Y. Teterahedron 2013, 69, 9848e9851.
. Fodran, P.; Minnaard, A. J. Org. Biomol. Chem. 2013, 11, 6919e6928.
4
.22.2. Co-injection of (S)-3A. (S)-3B, and (R)-3C. A 1:2:4 mixture
O was analyzed by GCeMS
under the conditions used for the analysis of (R)-1A: t 21.30 min
7
. Kristinsson, B.; Linderborg, K. M.; Kallio, H.; Haraldsson, G. G. Tetrahedron:
Asymmetry 2014, 25, 125e132.
of (S)-3A, (S)-3B, and (R)-3C in Et
2
R
8. Yew, J. Y.; Dreisewerd, K.; deOliveira, C. C.; Etges, W. J. PLoS ONE 2011, 6, 1e15 e
16898.
for (S)-3A, 21.41 min for (S)-3B, and 21.54 min for (R)-3C [see
Fig. 6b].
9. Chin, J. S. R.; Ellis, S. R.; Pham, H. T.; Blanksby, S. J.; Mori, K.; Ko, Q. L.; Etges, W.
J.; Yew, J. Y. eLife 2014, 3, 1e18 e 01751.
1
1
0. Mori, K. J. Chem. Ecol. 2014, 40, 214.
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12. A review on GCeMS: Dickschaft, J. S. Nat. Prod. Rep. 2014, 31, 838e861.
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dyanathan, R. Org. Lett. 1999, 1, 447e450.
4
.23. HPLC analysis of (R)-1A, and 1B
1
The synthetic triacylglycerols 1A, 1B, 3A, 3B, and 3C were
subjected to HPLC analysis. Only the separation of (R)-1A from 1B
was possible under the following conditions. Apparatus: Shi-
1
4. David, S.; Hanessian, S. Tetrahedron 1985, 41, 643e663.
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3
440e3444.
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Wada, S. J. Oleo Sci. 2011, 60, 345e350.
1
1
madzu prominence; column: Sunrise C28
ChromaNik Technology); column temperature: 10 C; eluent:
MeCN/THF¼100:0 (0 min)e75:25 (50 min); flow rate: 1.0 mL/min;
sample: (R)-1Aþ1B in MeCN; t 20.797 min [(R)-1A], 21.591 min
1B).
5
m
, 250 mmꢃ4.6 mm i.d.
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1
2
R
1
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