Synthesis of antineoplastic analogs of aplysiatoxin with various side chain structures

Article abstract of DOI:10.3987/COM-12-S(N)8

We have recently developed a simplified analog of aplysiatoxin with anti-proliferative activity (1). To investigate the structure-activity relationship of its side chain, an alternative synthetic route of 1 has been established. Via the key intermediate 6

Full text of DOI:10.3987/COM-12-S(N)8

HETEROCYCLES, Vol. 86, No. 1, 2012
281
HETEROCYCLES, Vol. 86, No. 1, 2012, pp. 281 - 303. © 2012 The Japan Institute of Heterocyclic Chemistry
Received, 29th March, 2012, Accepted, 27th April, 2012, Published online, 2nd May, 2012
DOI: 10.3987/COM-12-S(N)8
SYNTHESIS OF ANTINEOPLASTIC ANALOGS OF APLYSIATOXIN
WITH VARIOUS SIDE CHAIN STRUCTURES
Yuki Shu,1 Ryo C. Yanagita,1,2 Harukuni Tokuda,3 Nobutaka Suzuki,3 and
Kazuhiro Irie1,*
1Division of Food Science and Biotechnology, Graduate school of Agriculture,
Kyoto University, Kyoto 606-8502, Japan (e-mail: irie@kais.kyoto-u.ac.jp);
2Department of Applied Biological Science, Faculty of Agriculture, Kagawa
3
University, Kagawa 761-0795, Japan; Department of Complementary and
Alternative Medicine, Clinical R&D, Graduate School of Medical Science,
Kanazawa University, Kanazawa 920-8640, Japan
Abstract – We have recently developed a simplified analog of aplysiatoxin with
anti-proliferative activity (1). To investigate the structure–activity relationship
of its side chain, an alternative synthetic route of 1 has been established. Via the
key intermediate 6, p-hydroxyl or o,m-dihydroxyl derivatives (4 and 5) as well as
1 were synthesized and their biological activities were evaluated. Although the
position of the hydroxyl group in the benzene ring did not change the affinity for
protein kinase C isozymes or the ability to induce the Epstein-Barr virus early
antigen, anti-proliferative activities against several human cancer cell lines of 1
were superior to those of 4.
INTRODUCTION
Protein kinase C (PKC) is a family of serine/threonine kinases that play a pivotal role in cell proliferation,
differentiation, and apoptosis.1 Eleven PKC isozymes are classified into three groups: conventional (!,
"I, "II, #), novel ($, %, &, '), and atypical ((, )/*).2 Naturally-occurring tumor promoters such as
12-O-tetradecanoylphorbol 13-acetate (TPA), teleocidin B-4, and aplysiatoxin (ATX) bind to tandem C1
domains (C1A, C1B) in the regulatory regions of conventional and novel PKC isozymes, inducing their
translocation to the cellular membrane, driven by an affinity for anionic phospholipids, resulting in the
abnormal activation of PKC.3
Dedicated to Prof. Ei-ichi Negishi on the occasion of his 77th birthday.

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HETEROCYCLES, Vol. 86, No. 1, 2012
HO
O
OAc
MeO2C
R1
R1
O
O
H
H
1: R1 = Me, R2 = R3 = H, R4 = OH
2: R1 = R2 = R3 = R4 = H
O
O
OH
O
O
O
OMe
Br
OH
OH
H
O
O
O
3: R1 = Me, R2 = R3 = R4 = H
4: R1 = Me, R2 = H, R3 = OH, R4 = H
5: R1 = Me, R2 = OH, R3 = H, R4 = OH
O
O
O
O
O
H
O
H
O
R2
OH
OH
HO
OH
R4
C3H7
O
CO2Me
R3
bryostatin 1 (bryo-1)
aplysiatoxin (ATX)
simplified analogs of ATX
Figure 1. Structure of bryostatin 1 (bryo-1), aplysiatoxin (ATX), and simplified analogs of ATX (1 – 5).
Bryostatin 1 (bryo-1)4 is also a potent activator of PKC isolated from the marine bryozoan Bugula
neritina. Although bryo-1, like tumor promoters, binds to the C1 domains of PKC isozymes and
activates them, it exhibits little tumor-promoting activity.5 Bryo-1 has anticancer activity and is
currently undergoing clinical trials for the treatment of solid tumors, leukemia, and lymphoma.6 Bryo-1
is also considered to have therapeutic potential for Alzheimer's disease7 (AD) and AIDS8 where PKC
isozymes are involved. However, the yield of bryo-1 isolated from natural sources is quite low.9
Recently, efficient means of producing bryo-related compounds have been reported,10 but it remains
difficult to obtain a sufficient amount of bryos for clinical use.
While other natural and synthetic PKC activators such as TPA and teleocidin analogs also have potential
for the treatment of cancer11 and AD,12 serious adverse effects such as gross hematuria, a grand mal
seizure, syncope, and hypotension were encountered during a phase I clinical trial.11 Pleiotropic effects
including tumor-promoting activity of these compounds would thus be of particular concern. Since
hydrophobicity of PKC activators generally correlates with their tumor-promoting ability,13 prostratin
(12-deoxyphorbol 13-acetate), a less hydrophobic phorbol ester without tumor-promoting activity, is
promising in the anti-HIV therapy.14 However, isolation yield of prostratin from natural sources was
poor like bryo-1, and its binding potency for PKC isozymes was very weak.
To solve these problems, we have developed simplified analogs of ATX (1 and 2)15 with less
hydrophobicity. Compound 1, synthesized in only 22 steps, behaved like bryo-1 in the translocation of
PKC$, a PKC isozyme involved in anti-tumor promotion and anti-proliferative effects in several cancer
cell lines,16,17 and in the induction of the Epstein-Barr virus early antigen (EBV-EA). The
anti-proliferative activity of 1 against many human cancer cell lines was comparable to that of bryo-1.15
In the EBV-EA induction test, 1 showed weak EA induction and suppressed the induction by the tumor
promoter TPA, suggesting 1 as well as bryo-1 to be an anti-tumor promoter rather than tumor promoter.15

HETEROCYCLES, Vol. 86, No. 1, 2012
283
OTES
O
OTBDPS
7
O
O
O
O
O
THPO
S
S
OH
O
O
O
O
O
O
8
O
OTES
OH
OBn
OH
CO2H
4
key intermediate 6
OBn
9
Scheme 1. Retrosynthetic analysis of 4.
We have recently synthesized a dehydroxyl derivative of 1 (3), similar in affinity for PKC$ to 1.18
While the anti-proliferative activities of 3 against 39 human cancer cell lines were almost equivalent to
those of 1, effects on some cell lines, e.g., LOX-IMVI melanoma and St-4 stomach cancer cell lines, were
different from those of 1.18 The anti-tumor-promoting activity of 3 estimated by the EBV-EA induction
test was weaker than that of 1,18 indicating the phenolic hydroxyl group of 1 to be important for the
activity. Therefore, it is necessary to investigate the influence of this group on various biological
activities for the development of analogs with less adverse effects. Although the synthesis of 1 was
established,15 it is not easy to modify its side chain. Notably, derivatives with an o- or p-hydroxyl group
on the benzene ring cannot be synthesized by the previous route15 because of the oxidation at the benzyl
position in the last stages of the synthesis. In this paper, we describe an alternative route for producing 1
via a key intermediate (6) with a primary hydroxyl group in the side chain. New analogs of 1 with
p-hydroxyl (4) or o,m-dihydroxyl groups (5) were synthesized using the key intermediate, and their
biological activities were evaluated.
RESULTS AND DISCUSSION
To elucidate the effects of a phenolic hydroxyl group in the benzene ring on biological activities, we
planned the synthesis of 4 and 5 as shown in Scheme 1. The production of 4 and 5 could be quite
difficult through the previous route15 where oxidative cleavage of the double bond with KMnO4 was
employed before final cyclization of the diolide ring. A benzyloxy group at the o- or p-position of the
alkyl benzene would activate the aromatic ring to induce a side reaction (e.g., oxidation at the benzyl
position). Based on this, we planned an alternative route via the key intermediate 6. This intermediate
has a common structure of each derivative (4 and 5), and each side chain can be inserted in the final
stages of the synthesis. This route also enables us to synthesize derivatives of 1 with various
substituents more easily.

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HETEROCYCLES, Vol. 86, No. 1, 2012
OH
OBoc
(Boc)2O
1) TBDPS-Cl, DIPEA, CH2Cl2
NaHMDS
1) IBr, CH2Cl2, toluene
2) (COCl)2, DMSO, Et3N, CH2Cl2
OH
HO
THF
65%
2) K2CO3, MeOH
52% in two steps
3) Ag2O, TiCl4, Ti(Oi-Pr)4
(S)-BINOL, allyl-SnBu3, CH2Cl2
OTBDPS
OTBDPS
1,4-butanediol
10
11
74% in three steps, 92% ee
S
S
OH
O
OTES
TBDPSO
S
TES-Cl
O
OTHP
1) AcOH/THF/H2O
DMAP, Et3N
8
S
2) 2,2-dimethoxypropane
CSA, CH2Cl2
OTHP
OH OTES
CH2Cl2
n-BuLi, THF
OTBDPS
OTBDPS
OHC
81%
85%
67% in two steps
13
12
7
TBDPSO
TBDPSO
Ag2O, TiCl4, Ti(Oi-Pr)4
(S)-BINOL, allyl-SnBu3
TPAP, NMO
MS4Å
HO
TBDPSO
S
S
S
S
OH
O
O
O
O
CH2Cl2
CH2Cl2
75%
S
H
S
O
O
50%, 93% de
14
15
16
4
4
HO
H
Hg(ClO4)2·6H2O
MeCN/CH2Cl2/H2O
AcOH/THF/H2O
86%
TBDPSO
O
O
13
HO
10
H
H
TBDPSO
O
9
S
S
O
12
OH OH
TBDPSO
OH
ZnCl2
CH2Cl2
90%
17
18
36%
19
46%
O
BnO
CO2H
OTES
1) NaIO4, KMnO4
pH 7.2 buffer
t-BuOH
O
O
9
O
OTBDPS
TESO
OBn
O
O
OTBDPS
TCB-Cl, Et3N
DMAP, toluene
2) HF·pyr
pyridine, THF
OH
18
90%
52% in two steps
20
15
5
16
4
3
12
11
6
8
O
O
O
13
HO2C
7
TCB-Cl
Et3N, DMAP
TPAP, NMO
MS4Å
O
2
O
O
10
CHO
14
1
OH
OH
9
O
O
O
OH
O
O
O
O
17
toluene
43%
CH2Cl2
73%
19
O
20
O
O
18
OBn
OBn
OBn
key intermediate 6
22
21
22
5
23
10
4
12
6
O
O
O
3
13
11
7
2
O
O
Pd(OH)2/C
23 or 24
P Ph3Br
R1
14
15
8
1
9
O
O
O
O
O
O
24
16
R1
R1
EtOAc, MeOH
n-BuLi, THF
21
20
17
27
26
O
25
18
R3
OBn
R3
OH
R3
41% (25)
41% (26)
93% (4)
quant. (5)
19
R2
R2
R2
R1 = H, R2 = OBn, R3 = H
(25)
(26)
R1 = H, R2 = OH, R3 = H
R1 = OH, R2 = H, R3 = OH
(4)
(5)
R1 = H, R2 = OBn, R3 = H
(23)
(24)
R1 = OBn, R2 = H, R3 = OBn
R1 = OBn, R2 = H, R3 = OBn
Scheme 2. Synthesis of4 and 5.

HETEROCYCLES, Vol. 86, No. 1, 2012
285
Synthesis of the key intermediate (6) was carried out by referring to our previous synthetic scheme for 115
with appropriate modifications (Scheme 2). Synthesis of 6 began with the preparation of known
(4R)-1-(tert-butyldiphenylsilyloxy)hept-6-en-4-ol19 (10, 92% ee) from 1,4-butanediol in three steps
including protection of one hydroxyl group with tert-butyldiphenylsilyl (TBDPS) ether, Swern oxidation,
and asymmetric Maruoka's allylation.20 Protection of the alcohol (10) with tert-butyl carbonate provided
11. Stereoselective iodocarbonate cyclization by Duan and Smith21 followed by treatment with K2CO3
in MeOH gave an epoxide (12). The hydroxyl group of 12 was protected with triethylsilyl (TES) ether
to yield the epoxide unit (7).
The epoxide (7) was coupled with 8, which was prepared from [(4-(1,3-dithian-
2-yl)-4-methylpentyl)oxy]-triisopropylsilane,15 to yield 13.
Selective deprotection of
2-tetrahydropyranyl (THP) and TES groups of 13, followed by protection of a resulting diol with
2,2-dimethoxypropane afforded 14. After several trials, it was found that THP is most appropriate to
protect the hydroxyl group of 8. Compound 14 was converted into an aldehyde (15) by Ley oxidation22
followed by Maruoka's asymmetric allylation20 to give 16 (93% de). Deprotection of the isopropylidene
group of 16 afforded a diol (17). Subsequent cleavage of the dithiane gave a mixture of spiroketals (18
and 19) at a ratio of 1:1.3. Their configurations were determined by NOESY experiments; NOE
cross-peaks were observed between H-12 and C10-OH, and between H-4. and H-9eq. in 18, and between
H-4 and H-13 in 19. The undesired isomer (19) was converted into the desired one (18) by chelation
with zinc chloride.23
The carboxylic acid unit (9) was synthesized from (R)-1-(benzyloxy)-3-(1,3-dithian-2-yl)-propan-2-ol24
prepared from (R)-(!)-glycidyl ether, by protection of a hydroxyl group with TES ether, cleavage of
dithiane, and Pinnic oxidation.25 Compound 18 was condensed with 9 by the method of Yamaguchi and
co-workers.26 The resultant 20 was converted to a carboxylic acid (21) by oxidative cleavage of the
olefin followed by deprotection of TES and TBDPS. Further Yamaguchi's macrolactonization26
afforded the key intermediate 6 in 18 steps from 1,4-butanediol with an overall yield of 0.6%. Although
21 had two hydroxyl groups, only the desired one reacted with the carboxyl group to close the ring
because of the long distance between another hydroxyl group and the carboxyl group.
The synthesis of 4 and 5 was completed via the key intermediate 6, which was converted to an aldehyde
(22). The side chain units (23 and 24) were prepared by conventional methods, bromination and heating
with triphenylphosphine. Wittig reactions of 22 with each side chain unit provided 25 and 26 as 2:1 and
4:5 E/Z mixtures, respectively. Finally, catalytic hydrogenation of 25 and 26 provided 4 and 5,
respectively. Compound 1 was also obtained similarly from 22 (see experimental section).

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HETEROCYCLES, Vol. 86, No. 1, 2012
Table 1. Ki Values for the Inhibition of [3H]PDBu's Binding by 1 – 5 and ATX
Ki (nM)
PKC C1
Peptides
1a
2a
3b
4
5
ATXb
58 (6)c
170 (30)
6.6 (1.0)
180 (30)
1400 (400)
44 (8)
0.40
12
!-C1A
$-C1A
$-C1B
63
140
7.4
2400
6800
170
120
130
9.8
0.41
a Cited from ref. 15. b Cited from ref. 18. c Standard deviation from triplicate experiments.
Table 2. Log GI50 Values for 1, 3, 4, and Bryo-1 against Several Human Cancer Cell Lines
Log GI50
Cancer type
Cell Line
1a
3b
4
Bryo-1c
–6.33
!5.61
!5.43
!5.60
!5.32
!5.74
!5.55
!5.33
–6.28
–5.67
!5.53
!5.83
!5.49
!5.17
!6.05
!6.09
–6.32
–5.16
!5.26
!5.81
!5.12
!4.97
!5.12
!5.14
HBC-4
MDA-MB-231
HCC2998
NCI-H460
A549
NRd
!5.20
!5.30
!5.60
!5.20
NRd
Breast
Colon
Lung
Melanoma
Stomach
LOX-IMVI
St-4
NRd
NRd
MKN45
a Cited from Ref. 15. b Cited from Ref. 18. c Cited from Ref. 31. d Not reported.
Compounds 4 and 5 were initially evaluated for their affinity for the synthetic C1 domains of PKC! and $
by inhibition of the specific binding of [3H]phorbol 12,13-dibutylate (PDBu) as reported previously.27,28
!-C1A, the major PDBu-binding site of PKC!,28 was selected as representative of conventional PKC
isozymes. Both the C1A and C1B domains of PKC$ were employed since binding to these domains
could be important for bryo-1-like activities.29 The affinity of 4 for these peptides was almost equal to
that of 1 (Table 1). This suggests that the position of the phenolic hydroxyl group at the side chain
might not affect the binding to PKC! and $-C1 peptides. The side chain of 1 would interact with
membrane phospholipids nonspecifically in the PKC–ligand–phospholipid ternary complex, as that of
ATX.30 In contrast, the affinity of 5 with two phenolic hydroxyl groups for PKC! and $-C1 peptides
decreased, possibly because of decreased hydrophobicity. The affinity of 5 was stronger than that of 2
lacking the dimethyl group at the spiroketal moiety, though 5 is slightly more hydrophilic than 2 (Clog P

HETEROCYCLES, Vol. 86, No. 1, 2012
287
of 2: 1.9, that of 5: 1.6). Although the side chain of 5 appears to interact non-specifically with
membrane phospholipids, the affinity of 5 for PKC isozymes might remain to some extent.
Figure 2. Epstein–Barr virus early antigen (EBV-EA)-induction test for 1, 4, and 5. a) EA-inducing
ability of TPA, 1, 4, and 5. Percentages of EA-positive cells are shown. Error bars
represent the standard error of the mean (SEM, n = 3). b) Inhibitory effects of 1, 4, and 5
on EBV-EA production induced by 32 nM of TPA. Percentages of EA-positive cells are
shown. Error bars represent SEM (n = 3). *P<0.01 vs. TPA 32 nM (t-test).
Anti-proliferative activity of 4 against a panel of 39 human cancer cell lines was evaluated as described
previously.32
Since compounds with weak affinity for PKC$ were deduced to show low
anti-proliferative activity as observed in 2,15 only 4 was subjected to evaluation. The growth inhibitory
activity was expressed as the GI50 (M), the concentration required to inhibit cell growth by 50% compared
to an untreated control. The average of the log GI50 values of each 39 human cancer cell line was
expressed as MG-MID.
Compound 4 showed anti-proliferative activity comparable to 1 and 3; the MG-MID of 4 was –4.97,
almost equal to those of 1 and 3 (–4.98 and !5.09, respectively). The cell lines with log GI50 values less
than –5.10 in 1 are listed in Table 2. Slightly stronger activity of 3 without phenolic hydroxyl group
might be ascribable to its increasing membrane permeating ability.18 While PKC binding ability of 1
and 4 were almost equal to each other, 1 showed stronger anti-proliferative activity against several of the
cell lines in Table 2, especially MDA-MB-231, LOX-IMVI, and St-4 cells, than 4. Compound 1 also
showed stronger activity against LOX-IMVI than 3. These results suggest that there might be targets
other than PKC isozymes that the phenolic hydroxyl group at meta-position interacts with.

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HETEROCYCLES, Vol. 86, No. 1, 2012
The most likely adverse effects of 1 and its derivatives would be tumor-promotion because these
compounds possess the skeleton of tumor-promoting ATX. Hence, possible tumor-promoting activity
was estimated by the Epstein–Barr virus early antigen (EBV-EA) induction test as described previously.33
EBVs, strictly controlled by host human lymphoblastoid Raji cells, are activated by tumor promoters to
produce early antigen.34 As shown in Figure 2a, TPA, a potent tumor promoter, strongly induced
EBV-EA production at 100 nM. On the other hand, 4 and 5 as well as 1 showed weak EA induction
even at 1000 nM (Figure 2a), with 5 slightly weaker than 1 and 4.
Compound 1 exhibited not only
weak EA-induction but also an inhibitory effect on the EA-production induced by TPA.15 Similarly, 100
nM of 4 and 5 both significantly suppressed the EA induction by TPA (32 nM) (Figure 2b). These
results suggest that anti-tumor-promoting activity might not correlate with the affinity for PKC isozymes
and that the existence of a phenolic hydroxyl group would be important for inhibitory activity against
tumor promoters as reported previously.18
In summary, we developed an alternative synthetic route for 1 to modify its side chain. Using this route
via the key intermediate (6), new derivatives with hydroxyl groups at the p- or o,m-positions of the
benzene ring (4 and 5) as well as 1 were synthesized. Many derivatives of 1 with various side chain
structures would be available by this route. The affinity for PKC! and $-C1 peptides and
anti-tumor-promoting activity of 4 were almost the same as those of 1. However, the anti-proliferative
activity of 4 against several cancer cell lines was slightly different from that of 1. Further study on the
structure–activity relationship of the side chain of 1 is necessary for its structural optimization as a
therapeutic lead.
EXPERIMENTAL
General remarks. The following spectroscopic and analytical instruments were used: Digital
1
13
Polarimeter, Jasco P-2200; H, C, and 2-D NMR, AVANCE III 400 and AVANCE III 500 (Bruker,
Germany, ref. TMS, 296 K); HPLC, Waters Model 600E with a Model 2487 UV detector; HR-FAB-MS
and HR-EI-MS, JMS-600H and JMS-700 (JEOL, Tokyo, Japan); HPLC was carried out on an
SL12S05-2510WT (silica gel, 10 mm i.d. " 250 mm) column (Yamamura Chemical Laboratory, Japan).
Wako gelTM C-200 (silica gel, Wako Pure Chemical Industries, Japan) and YMC A60-350/250 gel (ODS,
Yamamura Chemical Laboratory) were used for column chromatography. [3H]PDBu (19.6 Ci/mmol)
was purchased from PerkinElmer Japan, Yokohama. All other chemicals and reagents were purchased
from chemical companies and used without further purification.
Synthesis ofꢀthe epoxide unit 7. To a solution of (4R)-1-(tert-butyldiphenylsilyloxy)hept-6-en-4-ol
(10) (1.77 g, 4.80 mmol) in THF (25 mL) was added dropwise 1 M NaHMDS in THF (6.0 mL, 6.0 mmol,
1.25 equiv.) at 4 °C. After 30 min of stirring, (Boc)2O (1.40 g, 6.42 mmol, 1.33 equiv.) was added, and

HETEROCYCLES, Vol. 86, No. 1, 2012
289
the reaction mixture was stirred for 6 h at rt. The reaction was quenched with brine (30 mL) and water
(10 mL), and the mixture was extracted with EtOAc. The combined organic layers were washed with
brine, dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by column
chromatography (silica gel, 1% EtOAc/hexane) to afford 11 (1.46 g, 3.12 mmol, 65%) as clear oil.
1
Compound 11: [!]D +6.5° (c 1.28, CHCl3, 20.8 °C); H NMR $ (400 MHz, CDCl3, 0.038 M) ppm: 1.04
(9H, s), 1.47 (9H, s), 1.59-1.78 (4H, m), 2.34 (2H, t, J = 7.1 Hz), 3.66 (2H, m), 4.69 (1H, m), 5.05-5.12
13
(2H, m), 5.76 (1H, m), 7.36-7.40 (6H, m), 7.65 (4H, m); C NMR $ (125 MHz, CDCl3, 0.107 M) ppm:
19.21, 26.85 (3C), 27.81 (3C), 28.33, 30.04, 38.71, 63.50, 76.42, 81.67, 117.80, 127.61 (4C), 129.55 (2C),
133.56 (2C), 133.93, 135.56 (4C), 153.37; HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 469.2761
(MH+, calcd for C28H41O4Si, 469.2774).
To a solution of 11 (6.84 g, 14.6 mmol) in toluene (77 mL) was added IBr (4.50 g, 21.8 mmol, 1.5 equiv.)
in CH2Cl2 (30 mL) dropwise at ꢀ78 °C under an Ar atmosphere. After 2 h of stirring at the same
temperature, the reaction was quenched with a 1:1 mixture of 10% aq. Na2S2O3 and saturated aq. NaHCO3
(200 mL), and the reaction mixture was extracted with EtOAc. The combined organic layers were
washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by
column chromatography (silica gel, 15% EtOAc/hexane) to afford an iodide. To a solution of the iodide
in anhydrous MeOH (70 mL) was added K2CO3 (7.46 g, 54.0 mmol, 5 equiv.). After 3 h of stirring at rt,
the reaction was quenched with H2O (120 mL), and the reaction mixture was extracted with EtOAc. The
combined organic layers were washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo.
The residue was purified by column chromatography (silica gel, 20% EtOAc/hexane) to yield 12 (2.88 g,
7.50 mmol, 52% in 2 steps) as clear oil. Compound 12: [!]D +7.6° (c 0.45, CHCl3, 18.2 °C); 1H NMR $
(400 MHz, CDCl3, 0.038 M) ppm: 1.05 (9H, s), 1.58-1.70 (5H, m), 1.80 (1H, dt, J = 14.3, 4.2 Hz), 2.51
(1H, dd, J = 5.0, 2.7 Hz), 2.69 (1H, d, J = 3.5 Hz, OH), 2.78 (1H, dd, J = 5.0, 4.1 Hz), 3.09 (1H, m), 3.70
(2H, t, J = 5.7 Hz), 3.90 (1H, m), 7.36-7.43 (6H, m), 7.67 (4H, m); 13C NMR $ (125 MHz, CDCl3, 0.107
M) ppm: 19.21, 26.85 (3C), 28.17, 30.46, 37.11, 46.40, 48.93, 54.71, 63.33, 127.64 (4C), 129.60 (2C),
133.82 (2C), 135.56 (4C); HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 385.2199 (MH+, calcd for
C23H33O3Si, 385.2199).
To a solution of 12 (2.88 g, 7.50 mmol) in CH2Cl2 (60 mL) was added DMAP (3.70 g, 30.1 mmol, 4
equiv.) and Et3N (5.20 mL, 37.7 mmol, 5 equiv.). To this solution was added TES-Cl (1.90 mL, 11.3
mmol, 1.5 equiv.) dropwise at 4 °C under an Ar atmosphere. After 10 min of stirring at the same
temperature, the reaction mixture was stirred at rt for an additional 1.5 h. The reaction was quenched
with saturated aq. NaHCO3 (100 mL), and the mixture was extracted with CH2Cl2. The combined
organic layers were washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The
residue was purified by column chromatography (silica gel, 2% EtOAc/hexane) to yield 7 (3.0 g, 6.0

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1
mmol, 81%) as clear oil. Compound 7: [!]D +2.3° (c 0.52, CHCl3, 21.6 °C); H NMR $ (400 MHz,
CDCl3, 0.024 M) ppm: 0.59 (6H, q, J = 7.9 Hz), 0.95 (9H, t, J = 7.9 Hz), 1.04 (9H, s) 1.58-1.63 (5H, m),
1.75 (1H, dt, J = 14.0, 5.9 Hz) 2.44 (1H, dd, J = 5.1, 2.7 Hz), 2.74 (1H, t, J = 4.5 Hz), 3.00 (1H, m), 3.67
(2H, m), 3.88 (1H, t, J = 5.4 Hz), 7.37-7.42 (6H, m), 7.66 (4H, m); 13C NMR $ (125 MHz, CDCl3, 0.107
M) ppm: 5.00 (3C), 6.91 (3C), 19.21, 26.85 (3C), 28.46, 33.57, 40.17, 46.92, 49.57, 63.94, 70.16, 127.60
(4C), 129.53 (2C), 134.01 (2C), 135.56 (4C); HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 499.3057
(MH+, calcd for C29H47O3Si2, 499.3064).
Synthesis of 8. To a solution of [(4-(1,3-dithian-2-yl)-4-methylpentyl)oxy]triisopropylsilane15 (2.59 g,
7.06 mmol) in THF (20 mL) was added 1 M tetrabutylammonium fluoride in THF (9.2 mL, 9.2 mmol, 1.5
equiv.) at 4 °C. After 1.5 h of stirring at rt, the reaction was quenched with saturated aq. NaHCO3 (80
mL), and the mixture was extracted with EtOAc. The combined organic layers were washed with brine,
dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by column
chromatography (silica gel, 30% EtOAc/hexane) to afford an alcohol. To a solution of the alcohol in
CH2Cl2 (15 mL) were added PPTS (357 mg, 1.42 mmol, 0.2 equiv.) and dihydropyran (0.72 mL, 8.0
mmol, 1.25 equiv.). After 40 h of stirring at rt, the reaction was quenched with saturated aq. NaHCO3
(30 mL), and the mixture was extracted with EtOAc. The combined organic layers were washed with
brine, dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by column
chromatography (silica gel, 4% EtOAc/hexane) to yield 8 (1.76 g, 5.79 mmol, 82% in 2 steps) as clear oil.
1
Compound 8 (a racemic mixture): H NMR $ (400 MHz, CDCl3, 0.071 M) ppm: 1.09 (6H, s), 1.47-1.63
(8H, m), 1.69-1.85 (3H, m), 2.05-2.09 (1H, m), 2.88 (4H, dd, J = 7.9, 3.3 Hz), 3.38 (1H, dt, J = 9.4, 6.9
Hz), 3.50 (1H, m), 3.72 (1H, dt, J = 9.4, 7.0 Hz), 3.88 (1H, m), 4.03 (1H, s), 4.58 (1H, dd, J = 4.4, 2.7
Hz); 13C NMR $ (125 MHz, CDCl3, 0.141 M) ppm: 19.76, 24.21, 25.40 (2C), 25.50, 26.18, 30.78, 31.45
(2C), 36.57, 37.96, 60.68, 62.49, 68.06, 98.89; HR-EI-MS: m/z 304.1537 (M+, calcd for C15H28O2S2,
304.1531).
Synthesis of the carboxylic acid unit 9. To a solution of (R)-1-(benzyloxy)-3-(1,3-dithian-
2-yl)propan-2-ol24 (560 mg, 1.97 mmol) in THF (15 mL) were added imidazole (400 mg, 5.88 mmol, 3.0
equiv.) and TES-Cl (0.50 mL, 3.0 mmol, 1.5 equiv.) at rt. After 1.5 h of stirring at rt under an Ar
atmosphere, the reaction was quenched with brine (25 mL), and the reaction mixture was extracted with
EtOAc. The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo.
The residue was purified by column chromatography (silica gel, 5% EtOAc/hexane) to afford a dithiane.
To a solution of the dithiane in MeCN (16 mL) and H2O (4.0 mL) were added NaHCO3 (440 mg, 5.2
mmol, 2.9 equiv.) and methyl iodide (4.39 mL, 70.4 mmol, 39 equiv.). After 18 h of stirring at rt, the
reaction was poured into H2O (40 mL), and the mixture was extracted with EtOAc. The combined
organic layers were washed with brine (50 mL), dried over Na2SO4, filtered, and concentrated in vacuo.

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The residue was purified by column chromatography (silica gel, 3% EtOAc/hexane) to afford an aldehyde
(475 mg). To a solution of the aldehyde (20.0 mg, 0.065 mmol) in t-BuOH (0.5 mL) was added
2-methyl-2-butene (0.33 mL, 0.066 mmol, 10 equiv.), and then cooled at 4 °C. To the reaction mixture,
a solution of NaClO4 (9.5 mg, 0.091 mmol, 1.4 equiv.) in saturated aq. NaH2PO4 (0.5 mL) was added, and
the mixture was stirred for 30 min at 4 °C. After being stirred for 1.5 h at rt, the mixture was poured
into H2O (8 mL), and extracted with EtOAc. The combined organic layers were washed with brine,
dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by column
chromatography (silica gel, 15% EtOAc/hexane) to yield 9 (18.5 mg, 0.0571 mmol, 73%) as yellow oil.
Since 9 was slightly labile at rt, it was prepared just before use and stored at –78 °C. Compound 9: [!]D
1
+16.9° (c 1.00, CHCl3, 8.9 °C); H NMR $ (400 MHz, CDCl3, 0.12 M) ppm: 0.60 (6H, q, J = 7.9 Hz),
0.93 (9H, t, J = 7.9 Hz), 2.52 (1H, dd, J = 15.4, 7.0 Hz), 2.69 (1H, dd, J = 15.4, 5.0 Hz), 3.40 (1H, dd, J =
13
9.6, 6.2 Hz), 3.49 (1H, dd, J = 9.6, 5.1 Hz), 4.29 (1H, m), 4.53 (2H, s), 7.32 (5H, m); C NMR $ (125
MHz, CDCl3, 0.099 M) ppm: 4.82 (3C), 6.69 (3C), 39.97, 68.24, 73.44, 73.77, 127.67 (2C), 127.69,
128.39 (2C), 138.00, 176.12; HR-FAB-MS (matrix: glycerol): m/z 325.1827 (MH+, calcd for C17H29O4Si,
325.1835).
Synthesis of the key intermediate 6. To a solution of 8 (45 mg, 0.15 mmol, 1.9 equiv.) in THF (0.3
mL) was added 1.6 M n-BuLi in hexane (110 µL, 0.176 mmol, 2.2 equiv.) under an Ar atmosphere.
After 1 h of stirring at rt, the reaction was cooled at 4 °C. A solution of 7 (40 mg, 0.08 mmol) in THF
(0.25 mL) was then added, and the reaction mixture was stirred for 3 h at 4 °C. The reaction was
quenched with saturated aq. NH4Cl (2.5 mL), and the reaction mixture was extracted with EtOAc. The
combined organic layers were washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo.
The residue was purified by column chromatography (silica gel, 4.5% EtOAc/hexane) to yield 13 (55 mg,
0.068 mmol, 85%) as clear oil. This procedure was repeated 47 times to give 2.46 g of 13. Compound
1
13 (a diastereomeric mixture); H NMR $ (500 MHz, CDCl3, 0.030 M) ppm: 0.61 (6H, q, J = 8.2 Hz),
0.96 (9H, t, J = 8.0 Hz), 1.04 (9H, s), 1.11 (3H, s), 1.13 (3H, s), 1.53-1.72 (15H, m), 1.82-1.91 (3H, m),
2.02 (1H, dd, J = 15.6, 1.5 Hz), 2.12 (1H, dd, J = 15.6, 8.0 Hz), 2.76-2.98 (4H, m), 3.38 (1H, m), 3.50
(1H, m), 3.67 (2H, t, J = 6.0 Hz), 3.73 (1H, m), 3.87 (1H, m), 3.96 (1H, m), 4.11 (1H, s, OH), 4.33 (1H,
br.t, J = 6.6 Hz), 4.58 (1H, t, J = 3.6 Hz), 7.36-7.43 (6H, m), 7.67 (4H, m); 13C NMR $ (125 MHz, CDCl3,
0.030 M) ppm: 5.18 (3C), 6.96 (3C), 19.25, 19.70, 22.30, 22.43, 23.14, 25.34, 25.54, 26.90 (3C), 27.17,
27.42, 28.30, 30.80, 33.04, 33.30, 45.53, 45.63, 45.68, 62.38, 63.63, 64.18, 67.81, 68.32, 70.37, 98.86,
127.60 (4C), 129.51 (2C), 134.14 (2C), 135.60 (4C); Some of the 13C NMR signals were doubled
according to the THP diastereomers ($45.53 and 98.86); HR-FAB-MS (matrix: 3-nitrobenzyl alcohol):
m/z 825.4410 (MNa+, calcd for C44H74O5S2Si2Na, 825.4414).

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Compound 13 (2.46 g, 3.07 mmol) dissolved in AcOH, THF and H2O (6:2:1 v/v, 63 mL) was stirred for
1.5 h at 55 °C. The solution was concentrated in vacuo with toluene (15 mL). The residue was diluted
with EtOAc (15 mL) and quenched with saturated aq. NaHCO3 (25 mL), and the mixture was extracted
with EtOAc. The combined organic layers were washed with brine, dried over Na2SO4, filtered, and
concentrated in vacuo. The residue was purified by column chromatography (silica gel, 50%
EtOAc/hexane) to yield a triol. To a solution of the triol in CH2Cl2 (23 mL) were added
2,2-dimethoxypropane (3.50 mL, 28.8 mmol, 12 equiv.) and 10-camphorsulfonic acid ꢁCSA, 55.3 mg,
0.238 mmol, 0.1 equiv.) at rt. The reaction mixture was stirred at rt for 2 h, and quenched with saturated
aq. NaHCO3 (50 mL). The resultant mixture was extracted with EtOAc. The combined organic layers
were washed with brine, dried over Na2SO4, and concentrated in vacuo. The residue was dissolved in
CH2Cl2 (25 mL), and silica gel (WakogelTM C-200, 1.5 g, 1 equiv. v/v) was added to the solution. The
mixture was stirred at rt for 2.5 h, and then filtered and concentrated in vacuo. The residue was purified
by column chromatography (silica gel, 25% EtOAc/hexane) to yield 14 (1.33 g, 2.07 mmol, 67% in 2
1
steps) as clear oil. Compound 14: [!]D +1.5° (c 0.26, CHCl3, 14.0 °C); H NMR $ (400 MHz, CDCl3,
0.014 M) ppm: 1.05 (9H, s), 1.13 (6H, s), 1.34 (3H, s), 1.38 (3H, s), 1.52-1.72 (10H, m), 1.82 (1H, m),
2.02 (1H, m), 2.21 (1H, dd, J = 16.3, 2.2 Hz), 2.35 (1H, dd, J = 16.3, 5.3 Hz), 2.68 (2H, m), 2.84 (1H, m),
3.08 (1H, m), 3.62-3.68 (4H, dt, J = 12.4, 6.2 Hz), 3.81 (1H, m), 4.23 (1H, dt, J = 11.7, 2.5 Hz), 7.35-7.42
(6H, m), 7.66 (4H, m); 13C NMR $ (100 MHz, CDCl3, 0.062 M) ppm: 19.23, 19.60, 22.47, 22.62, 24.84,
26.89 (4C), 27.00, 28.01, 28.24, 30.30, 32.67, 32.93, 38.60, 43.40, 43.52, 63.44, 63.81 (2C), 68.04, 68.90,
98.52, 127.61 (4C), 129.54 (2C), 134.01, 134.04, 135.57 (4C); HR-FAB-MS (matrix: 3-nitrobenzyl
alcohol): m/z 667.3302 (MNa+, calcd for C36H56O4S2SiNa, 667.3287).
To a solution of 14 (480 mg, 0.745 mmol) in CH2Cl2 (16 mL) were added N-methylmorpholine N-oxide
(131 mg, 1.12 mmol, 1.5 equiv.) and molecular sieve 4Å (MS4Å, 480 mg, 1.0 equiv. w/w).
Tetrapropylammonium perruthenate (TPAP, 12.2 mg, 0.0347 mmol, 4.69 mol%) was then added, and the
reaction mixture was stirred for 30 min at rt. The mixture was concentrated in vacuo, and the residue
was purified by column chromatography (silica gel, 10% EtOAc/hexane) to yield 15 (360 mg, 0.56 mmol,
1
75%) as clear oil. Compound 15: [!]D +2.9° (c 0.56, CHCl3, 23.3 °C); H NMR $ (400 MHz, CDCl3,
0.050 M) ppm: 1.05 (9H, s), 1.12 (6H, s), 1.34 (3H, s), 1.37 (3H, s), 1.51-1.72 (6H, m), 1.83 (1H, m),
2.05 (3H, m), 2.23 (1H, dd, J = 16.3, 2.0 Hz), 2.34 (1H, dd, J = 16.3, 5.4 Hz), 2.43 (2H, m), 2.70 (2H, m),
2.83 (1H, m), 3.07 (1H, m), 3.67 (2H, t, J = 6.3 Hz), 3.82 (1H, m), 4.23 (1H, dt, J = 11.7, 2.6 Hz),
7.35-7.42 (6H, m), 7.66 (4H, m), 9.78 (1H, t, J = 1.9 Hz); 13C NMR $ (100 MHz, CDCl3, 0.050 M) ppm:
19.23, 19.58, 22.61 (2C), 24.74, 26.84, 26.89 (3C), 27.04, 28.02, 29.34, 30.28, 32.69, 38.63, 40.09, 43.16,
43.65, 63.08, 63.80, 67.85, 68.85, 98.54, 127.60 (4C), 129.54 (2C), 134.01, 134.04, 135.57 (4C), 202.75;
HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 643.3340 (MH+, calcd for C36H55O4S2Si, 643.3311).

HETEROCYCLES, Vol. 86, No. 1, 2012
293
1 M TiCl4 in CH2Cl2 (0.37 mL, 0.37mmol, 0.32 equiv.) was diluted with CH2Cl2 (3.7 mL) at 4 °C under
an Ar atmosphere. Ti(Oi-Pr)4 (0.34 mL, 1.2 mmol, 1.0 equiv.) was added, and the solution was stirred
for 1 h at rt. Ag2O (232 mg, 1.00 mmol, 0.83 equiv.) was added, and the solution was stirred for 5 h at rt
in the dark. (S)-(–)-1,1'-bi-2-naphthol (430 mg, 1.5 mmol, 1.3 equiv.) was added after the solution was
diluted with CH2Cl2 (7.4 mL). Following 2 h of stirring at rt, the dark red mixture was added to a
solution of 15 (742 mg, 1.15 mmol) in Et2O (11.1 mL) at ꢀ15 °C. Allyl-SnBu3 (10.4 mL, 33.6 mmol, 30
equiv.) was added, and the mixture was stirred for 1 h at the same temperature. The resulting reaction
mixture was kept in a freezer at !20 °C for 18 h without stirring, and then stirred for 2 h at 4 °C. The
reaction was quenched with saturated aq. NH4Cl (25 mL), and the mixture was extracted with EtOAc.
The combined organic layers were filtered and washed with brine, dried over Na2SO4, filtered, and
concentrated in vacuo. The residue was purified by column chromatography (silica gel, 6%
EtOAc/hexane; ODS, 95% MeOH) to yield 16 (390 mg, 0.57 mmol, 50%, 93% de) as clear oil.
Diastereomeric excess was determined by the modified Mosher's method.35 Compound 16: [!]D +3.6° (c
0.80, CHCl3, 15.3 °C); 1H NMR $ (400 MHz, CDCl3, 0.018 M) ppm: 1.05 (9H, s), 1.12 (3H, s), 1.13 (3H,
s), 1.34 (3H, s), 1.38 (3H, s), 1.44-1.69 (9H, m), 1.84 (2H, m), 1.98 (1H, m), 2.15 (1H, m), 2.22 (1H, dd,
J = 16.3, 2.2 Hz), 2.35 (2H, m), 2.68 (2H, tt, J = 13.6, 4.4 Hz), 2.84 (1H, m), 3.08 (1H, m), 3.60 (1H, m),
3.67 (2H, t, J = 6.3 Hz), 3.80 (1H, m), 4.23 (1H, dt, J = 9.0, 2.5 Hz), 5.13 (1H, s), 5.16 (1H, m), 5.83 (1H,
m), 7.36-7.44 (6H, m), 7.66 (4H, m); 13C NMR $ (100 MHz, CDCl3, 0.018 M) ppm: 19.25, 19.61, 22.48,
22.72, 24.86, 26.92 (3C), 26.96, 27.05, 28.06, 30.33, 32.06, 32.73, 32.95, 38.65, 41.87, 43.54, 43.64,
63.52, 63.86, 68.08, 68.93, 71.42, 98.55, 118.18, 127.61 (4C), 129.54 (2C), 134.08, 134.81, 135.01,
135.59 (4C); HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 707.3589 (MNa+, calcd for
C39H60O4S2SiNa, 707.3600).
Compound 16 (495 mg, 0.724 mmol) was dissolved in AcOH, THF, and H2O (4:2:1 v/v, 8 mL). The
mixture was stirred for 50 min at 55 °C. The reaction was concentrated in vacuo with toluene. The
residue was diluted with EtOAc (10 mL) and quenched with saturataed aq. NaHCO3 (20 mL), and the
mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over
Na2SO4, filtered, and concentrated in vacuo. The residue was purified by column chromatography
(silica gel, 30 % EtOAc/hexane) to afford 17 (350 mg, 0.54 mmol, 75%) as a clear oil.
Compound 17:
[!]D +3.6° (c 1.32, CHCl3, 12.2 °C); 1H NMR $ (500 MHz, CDCl3, 0.011 M) ppm: 1.04 (9H, s), 1.13 (3H,
s), 1.13 (3H, s), 1.44-1.73 (9H, m), 1.80 (1H, m), 1.93-2.00 (3H, m), 2.18 (2H, m), 2.33 (1H, m),
2.83-3.01 (4H, m), 3.62 (1H, m), 3.69 (2H, t, J = 6.2 Hz), 3.89 (1H, m), 4.04 (1H, br.s, OH), 4.52 (1H, m,
OH), 4.56 (1H, br.s), 5.15 (2H, m), 5.83 (1H, m), 7.35-7.44 (6H, m), 7.67 (4H, m); 13C NMR $ (125 MHz,
CDCl3, 0.011 M) ppm: 19.24, 22.39, 22.63, 23.07, 26.92 (3C), 27.36, 27.54, 28.61, 32.06, 32.75, 34.30,
42.09, 44.48, 45.12, 45.59, 63.21, 64.17, 71.10, 71.29, 71.54, 118.33, 127.63 (4C), 129.55 (2C), 134.04

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(2C), 134.67, 135.62 (4C); HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 645.3498 (MH+, calcd for
C36H57O4S2Si, 645.3468).
To a solution of 17 (350 mg, 0.54 mmol) in MeCN (2.0 mL), CH2Cl2 (2.0 mL), and H2O (2.0 mL) was
added Hg(ClO4)2ꢂ6H2O (545 mg, 1.08 mmol, 2.0 equiv.) at 4 °C. After 45 min of stirring at the same
temperature, the reaction mixture was poured into EtOAc (15 mL) and saturated aq. Na2S2O3 (25 mL).
The organic layer was separated, and the aqueous layer was extracted with EtOAc. The combined
organic layers were washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The
residue was purified by column chromatography (5% ꢃ 10% EtOAc/hexane) to afford 18 (104 mg,
0.194 mmol, 36%) and 19 (133 mg, 0.248 mmol, 46%).
To a solution of 19 (148 mg, 0.276 mmol) in CH2Cl2 (6.0 mL) was added ZnCl2 (112 mg, 0.824 mmol,
3.0 equiv.) at rt. After 30 min of stirring at rt, the reaction was quenched with saturated aq. NaHCO3 (20
mL), and the mixture was extracted with EtOAc. The combined organic layers were washed with brine,
dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by column
chromatography (silica gel, 10 % EtOAc/hexane) to afford 18 (134 mg, 0.250 mmol, 90%) as clear oil.
Compound 18: [!]D +33.1° (c 0.735, CHCl3, 28.7 °C); 1H NMR $ (500 MHz, CDCl3, 0.056 M) ppm: 0.88
(3H, s), 0.95 (3H, s), 1.05 (9H, s), 1.34 (1H, m), 1.42-1.74 (10H, m), 2.20 (1H, m), 2.29 (2H, m), 3.69
(2H, t, J = 6.4 Hz), 3.78 (1H, t, J = 6.5 Hz), 3.81 (1H, d, J = 11.0 Hz, OH), 4.07 (1H, dt, J = 11.0, 3.1 Hz),
13
4.15 (1H, m), 5.09 (2H, m), 5.80 (1H, ddt, J = 17.2, 10.1, 7.2 Hz), 7.36-7.43 (6H, m), 7.67 (4H, m); C
NMR $ (125 MHz, CDCl3, 0.060 M) ppm: 19.26, 22.46, 25.50, 26.37, 26.92 (3C), 28.42, 29.29, 32.26,
33.29, 36.76, 37.98, 40.87, 63.72, 64.08, 65.59, 72.59, 102.76, 117.88, 127.59 (4C), 129.50 (2C), 134.23
(2C), 134.81, 135.60 (4C); HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 559.3204 (MNa+, calcd for
1
C33H48O4SiNa, 559.3220). Compound 19: [!]D !5.2° (c 1.14, CHCl3, 32.9 °C); H NMR $ (500 MHz,
CDCl3, 0.048 M) ppm: 0.85 (3H, s), 0.96 (3H, s), 1.05 (9H, s), 1.12 (1H, dt, J = 12.9, 3.3 Hz), 1.32-1.72
(8H, m), 1.89 (1H, td, J = 13.0, 5.0 Hz), 1.98 (1H, m), 2.05-2.20 (3H, m), 3.67 (2H, m), 3.79 (1H, m),
3.89 (1H, m), 4.22 (1H, m), 4.97 (2H, m), 5.75 (1H, ddt, J = 17.2, 10.1, 7.2 Hz), 7.35-7.47 (6H, m), 7.67
13
(4H, m); C NMR $ (125 MHz, CDCl3, 0.071 M) ppm: 19.23, 22.96, 25.70, 26.90 (3C), 27.47, 29.55,
32.07, 33.63, 36.21, 36.46, 38.02, 40.70, 62.42, 63.92, 68.68, 71.33, 102.29, 116.18, 127.61 (4C), 129.54
(2C), 134.12 (2C), 135.56, 135.59 (4C); HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 559.3222
(MNa+, calcd for C33H48O4SiNa, 559.3220).
To a solution of 9 (260 mg, 0.80 mmol, 1.7 equiv.) in toluene (12.5 mL) were added Et3N (0.14 mL, 1.3
mmol, 2.8 equiv.) and 2,4,6-trichlorobenzoyl chloride (0.14 mL, 0.87 mmol, 1.9 equiv.). After 2 h of
stirring at rt, the mixture was added to a solution of 18 (243 mg, 0.453 mmol) and DMAP (166 mg, 1.36
mmol, 3 equiv.) in toluene (12.5 mL) at rt. The mixture was heated to 50 °C and stirred for 1.5 h at the
same temperature. The reaction mixture was poured into H2O (30 mL), and the mixture was extracted

HETEROCYCLES, Vol. 86, No. 1, 2012
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with EtOAc. The combined organic layers were washed with brine, dried over Na2SO4, filtered, and
concentrated in vacuo. The residue was purified by column chromatography (silica gel, 3%
EtOAc/hexane) to afford 20 (343 mg, 0.407 mmol, 90%) as clear oil. Compound 20: [!]D +22.3° (c
0.360, CHCl3, 14.7 °C); 1H NMR $ (400 MHz, CDCl3, 0.078 M) ppm: 0.59 (6H, q, J = 7.8 Hz), 0.84 (3H,
s), 0.92 (9H, t, J = 7.8 Hz), 0.95 (3H, s), 1.05 (9H, s), 1.35-1.51 (7H, m), 1.64 (4H, m), 2.26 (3H, m), 2.49
(1H, dd, J = 15.3, 8.0 Hz), 2.60 (1H, dd, J = 15.3, 4.6 Hz), 3.37 (1H, dd, J = 9.5, 6.1 Hz), 3.46 (1H, br.s),
3.47 (1H, dd, J = 9.5, 5.3 Hz), 3.68 (2H, m), 4.23 (1H, m), 4.34 (1H, m), 4.52 (2H, d, J = 2.1 Hz), 4.96
(1H, d, J = 8.3 Hz), 5.00 (1H, d, J = 11.9 Hz), 5.09 (1H, t, J = 3.3 Hz), 5.82 (1H, ddt, J = 17.3, 10.2, 7.1
13
Hz), 7.27-7.43 (11H, m), 7.67 (4H, m); C NMR $ (125 MHz, CDCl3, 0.009 M) ppm: 4.92 (3C), 6.79
(3C), 19.26, 21.53, 25.55, 26.50, 26.59, 26.93 (3C), 28.31, 32.15, 34.24, 34.61, 36.88, 40.74, 41.06, 63.91,
64.14, 68.11, 68.44, 71.68, 73.33, 74.27, 100.07, 116.56, 127.58 (4C), 127.59 (3C), 128.33 (2C), 129.46
(2C), 134.30 (2C), 135.21, 135.60 (4C), 138.27, 171.68; HR-FAB-MS (matrix: 3-nitrobenzyl alcohol):
m/z 865.4910 (MNa+, calcd for C50H74O7Si2Na, 865.4871).
To a suspension of NaIO4 (21.0 mg, 0.0981 mmol, 8.0 equiv.) in pH 7.2 buffer (1.0 mL) was added
KMnO4 (1.93 mg, 0.0122 mmol, 1.0 equiv.) and stirred for 10 min at rt. The mixture was added to a
solution of 20 (10.3 mg, 0.0122 mmol) in t-BuOH (1.0 mL). After 1 h of stirring at rt, the reaction was
quenched with Na2S2O3 (5.9 mg). The resulting mixture was poured into EtOAc (8 mL) and H2O (8 mL).
The organic layer was separated, and the aqueous layer was extracted with EtOAc. The combined
organic layers were washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The
residue was purified by column chromatography (silica gel, 10% EtOAc/hexane containing 0.5% AcOH)
to afford a carboxylic acid (6.9 mg). To a solution of the carboxylic acid (35.8 mg, 0.0416 mmol) in
THF (2.0 mL) was added a mixture of HFꢂpyridine, pyridine, and THF (1:2:8 v/v, 1.7 mL). After 11.5 h
of stirring at 4 °C, the reaction was diluted with H2O (5 mL) and warmed to rt. The mixture was
extracted with EtOAc. The combined organic layers were washed with brine, dried over Na2SO4,
filtered, and concentrated in vacuo. The residue was purified by column chromatography (silica gel,
70% EtOAc/hexane containing 0.5% AcOH) to afford 21 (16.4 mg, 0.032 mmol, 52% in 2 steps) as clear
oil. Compound 21: [!]D +25.0° (c 0.90, CHCl3, 29.0 °C); 1H NMR $ (500 MHz, CDCl3, 0.065 M) ppm:
0.92 (3H, s), 0.99 (3H, s), 1.39-1.77 (11H, m), 2.09 (1H, br.d, J = 15.3 Hz), 2.47 (1H, dd, J = 14.4, 4.5
Hz), 2.56 (2H, m), 2.71 (1H, dd, J = 14.4, 8.2 Hz), 3.52 (2H, dd, J = 5.2, 1.0 Hz), 3.66 (2H, dd, J = 6.0,
13
4.4 Hz), 4.14 (1H, br.s), 4.27 (2H, m), 4.58 (2H, s), 5.18 (1H, s), 7.27-7.37 (5H, m); C NMR $ (125
MHz, CDCl3, 0.065 M) ppm: 22.95, 24.75, 26.47, 28.14, 28.36, 32.23 (2C), 34.09, 36.85, 39.20, 41.63,
62.65, 64.24, 67.48, 67.57, 69.64, 73.57 (2C), 101.35, 127.92 (2C), 127.93, 128.50 (2C), 137.58, 171.52,
173.38; HR-FAB-MS (matrix: glycerol): m/z 509.2743 (MH+, calcd for C27H41O9, 509.2751).

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HETEROCYCLES, Vol. 86, No. 1, 2012
To a solution of 21 (17.0 mg, 0.0335 mmol) in toluene (5.5 mL) were added Et3N (20 mL, 0.2 mmol, 6.0
equiv.) and 2,4,6-trichlorobenzoyl chloride (5.8 µL, 0.037 mmol, 1.1 equiv.). After 3 h of stirring at rt,
the mixture was diluted with toluene (16.5 mL). It was then added dropwise to a solution of DMAP
(61.2 mg, 0.05 mmol, 15 equiv.) in toluene (45 mL) at 4 °C over 4.5 h. The resulting mixture was
stirred at rt for an additional 30 min, and poured into water (40 mL). The mixture was extracted with
EtOAc. The combined organic layers were washed with brine, dried over Na2SO4, filtered, and
concentrated in vacuo. The residue was purified by column chromatography (silica gel, 40 %
EtOAc/hexane) to afford 6 (7.0 mg, 0.014 mmol, 43%) as clear oil. Compound 6: [!]D +63.3° (c 0.41,
1
CHCl3, 28.3 °C); H NMR $ (500 MHz, CDCl3, 0.017 M) ppm: 0.87 (3H, s, H3-15 or 16), 1.01 (3H, s,
H3-15 or 16), 1.35-1.55 (7H, m, H2-4, H-5a, H2-10, H2-12), 1.59-1.73 (4H, m, H-5b, H-8a, H2-13), 1.84
(1H, br.s, OH), 2.34 (1H, dd, J = 12.7, 10.9 Hz, H-2a), 2.46 (1H, br.d, J = 15.6 Hz, H-8b), 2.52 (1H, dd, J
= 12.7, 2.8 Hz, H-2b), 2.76 (1H, dd, J = 16.9, 3.0 Hz, H-18a), 2.89 (1H, dd, J = 16.9, 11.6 Hz, H-18b),
3.56 (1H, dd, J = 10.1, 5.5 Hz, H-20a), 3.63 (1H, dd, J = 10.1, 3.7 Hz, H-20b), 3.70 (2H, m, H2-14), 3.87
(1H, tt, J = 10.9, 2.9 Hz, H-3), 4.26 (1H, m, H-11), 4.50 (1H, d, J = 12.0 Hz, Bn), 4.57 (1H, d, J = 12.0
Hz, Bn), 5.20 (1H, br.s, H-9), 5.25 (1H, m, H-19), 7.33 (5H, m, Bn); 13C NMR $ (125 MHz, CDCl3, 0.017
M) ppm: 21.27 (C-15 or 16), 25.31 (C-8), 25.89 (C-15 or 16), 27.25 (C-4), 28.24 (C-13), 31.84 (C-12),
34.73 (C-5), 34.83 (C-10), 36.92 (C-6), 37.48 (C-18), 42.75 (C-2), 62.43 (C-14), 63.58 (C-11), 68.46
(C-9), 68.99 (C-19), 70.32 (C-20), 70.74 (C-3), 73.51 (Bn), 100.51 (C-7), 127.71 (2C, Bn), 127.85 (Bn),
128.47 (2C, Bn), 137.78 (Bn), 169.96 (C-17), 170.31 (C-1). These NMR signals were assigned by
1H-1H COSY, HMQC, and HMBC. HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 491.2643 (MH+,
calcd for C27H39O8, 491.2645).
Synthesis of the side chain unit 24. To a solution of 2,5-dibenzyloxybenzyl bromide (68 mg, 0.18
mmol) in toluene (4 mL) was added PPh3 (65 mg, 0.25 mmol, 1.4 equiv.) and the mixture was heated to
80 °C. After 20 h of stirring at the same temperature, a brown precipitate formed. Toluene was
removed by decantation and the residue was triturated with ether. The white solid was separated by
filtration and washed well with hexane to yield a hydroscopic salt (24) (65.4 mg, 0.101 mmol, 56%).
Compound 24: mp. 85-100 °C;1H NMR $ (500 MHz, CDCl3, 0.27 M) ppm: 4.42 (2H, s), 4.89 (2H, s),
5.22 (2H, br.d, J = 13.6 Hz), 6.58 (1H, d, J = 8.8 Hz), 6.83 (1H, dt, J = 9.0, 2.9 Hz), 7.13 (3H, m), 7.23
(2H, m), 7.32-7.38 (6H, m), 7.50 (12H, m), 7.72 (3H, m); HR-FAB-MS (matrix: 3-nitrobenzyl alcohol):
m/z 565.2297 ([M–Br]+, calcd for C39H34O2P, 565.2296).
Synthesis of 4 and 5. To a solution of 6 (3.6 mg, 7.3 µmol) in CH2Cl2 (0.8 mL) were added
N-methylmorpholine-N-oxide (1.3 mg, 0.013 mmol, 1.8 equiv.) and MS4Å (4.0 mg, 1.1 equiv. w/w).
Tetrapropylammonium perruthenate (0.13 mg, 0.373 µmol, 5 mol%) was then added, and the reaction
mixture was stirred for 40 min at rt. The resultant mixture, loaded directly onto a silica gel column, was

HETEROCYCLES, Vol. 86, No. 1, 2012
297
purified by column chromatography (silica gel, 40% EtOAc/hexane) to afford 22 (2.6 mg, 5.3 µmol,
1
73%) as clear oil. Compound 22: [!]D +55.1° (c 0.20, CHCl3, 29.1 °C); H NMR $ (500 MHz, CDCl3,
0.019 M) ppm: 0.85 (3H, s), 0.98 (3H, s), 1.34-1.72 (8H, m), 1.81 (1H, m), 2.33 (1H, dd, J = 12.7, 10.9
Hz), 2.49 (3H, m), 2.62 (1H, m), 2.76 (1H, dd, J = 16.9, 3.0 Hz), 2.89 (1H, dd, J = 16.9, 11.4 Hz), 3.56
(1H, dd, J = 10.1, 5.5 Hz), 3.64 (1H, dd, J = 10.1, 3.8 Hz), 3.86 (1H, tt, J = 11.0, 3.0 Hz), 4.20 (1H, m),
4.50 (1H, d, J = 12.0 Hz), 4.57 (1H, d, J = 12.0 Hz), 5.20 (2H, m), 7.27-7.36 (5H, m), 9.79 (1H, t, J = 1.5
Hz); 13C NMR $ (125 MHz, CDCl3, 0.012 M) ppm: 21.33, 25.22, 25.84, 27.24, 28.14, 34.56, 34.69, 36.90,
37.44, 40.12, 42.71, 63.51, 68.17, 68.97, 70.30, 70.76, 73.50, 100.39, 127.71 (2C), 127.85, 128.47 (2C),
137.77, 169.94, 170.27, 202.83; HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 489.2480 (MH+, calcd
for C27H37O8, 489.2488).
To a solution of the phosphonium bromide 2336 (21.5 mg, 0.04 mmol, 5.1 equiv.) in THF (0.4 mL) was
added 1.6 M n-BuLi (20 µL, 0.032 mmol, 4.1 equiv.) at 4 °C. After 20 min of stirring at the same
temperature, the solution of 22 (3.0 mg, 6.2 µmol) in THF (0.25 mL) was added to the mixture at ꢀ78°C.
The reaction mixture was stirred for 3 h at the same temperature and warmed to 4 °C. After stirring for
30 min at 4 °C, the mixture was diluted with EtOAc (1.0 mL) and the reaction was quenched with
saturated aq. NH4Cl (2.5 mL). The organic layer was separated, and the aqueous layer was extracted
with EtOAc. The combined organic layers were washed with brine, dried over Na2SO4, filtered, and
concentrated in vacuo. The residue was purified by column chromatography (silica gel, 15%
EtOAc/hexane) to afford 25 (1.7 mg, 2.5 µmol, 41%) as clear oil. Compound 25: E-Alkene, 1H NMR $
(400 MHz, CDCl3, 0.004 M) ppm: 0.88 (3H, s), 1.02 (3H, s), 1.25-1.68 (10H, m), 2.31 (2H, m), 2.49 (2H,
m), 2.76 (1H, dd, J = 12.3, 3.1 Hz), 2.88 (1H, dd, J = 16.9, 11.5Hz), 3.60 (2H, m), 3.87 (1H, m), 4.23 (1H,
m), 4.48 (1H, d, J = 12.0 Hz), 4.57 (1H, d, J = 12.0 Hz), 5.04 (2H, s), 5.20 (2H, m), 6.14 (1H, dt, J = 15.8,
1
7.0 Hz), 6.33 (1H, d, J = 15.8 Hz), 6.90 (2H, d, J = 8.7 Hz), 7.24-7.44 (12H, m); Z-Alkene, H NMR $
(400 MHz, CDCl3, 0.004 M) ppm: 0.86 (3H, s), 0.95 (3H, s), 1.25-1.68 (10H, m), 2.31 (2H, m), 2.49 (2H,
m), 2.72 (1H, dd, J = 12.3, 3.0 Hz), 2.88 (1H, dd, J = 16.8, 11.2Hz), 3.60 (2H, m), 3.87 (1H, m), 4.23 (1H,
m), 4.50 (1H, d, J = 12.0 Hz), 4.57 (1H, d, J = 12.0 Hz), 5.06 (2H, s), 5.20 (2H, m), 5.60 (1H, dt, J = 11.6,
7.6 Hz), 6.35 (1H, d, J = 11.8 Hz), 6.93 (2H, d, J = 8.8 Hz), 7.24-7.44 (12H, m); HR-FAB-MS (matrix:
3-nitrobenzyl alcohol): m/z 669.3423 (MH+, calcd for C41H49O8, 669.3427).
To a solution of 25 (4.7 mg, 7.0 µmol) in EtOAc (0.7 mL) and MeOH (0.7 mL) was added Pd(OH)2/C
(1.3 mg, 30% w/w). The mixture was vigorously stirred under an H2 atmosphere for 4.5 h. The
reaction mixture was filtered and concentrated in vacuo. The residue was purified by HPLC (column:
SL12S05-2510WT; solvent: i-PrOH : CHCl3 : hexane = 8:12:80; flow rate: 3.0 mL/min; pressure: 510
psi; UV detector: 254 nm; retention time: 22.0 min) to afford 4 (3.2 mg, 6.5 µmol, 93%) as clear oil.
1
Compound 4; [!]D +40.7° (c 0.42, CHCl3, 29.3 °C); H NMR $ (500 MHz, CDCl3, 0.017 M) ppm: 0.86

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HETEROCYCLES, Vol. 86, No. 1, 2012
(3H, s, H3-22 or 23), 0.98 (3H, s, H3-22 or 23), 1.34-1.49 (8H, m, H2-4, H2-5, H2-10, H2-13), 1.51-1.66
(5H, m, H-8a, H2-12, H2-14), 2.35 (1H, br.t, J = 5.6 Hz, OH), 2.40 (1H, dd, J = 12.9, 10.9 Hz, H-2a), 2.49
(1H, br.d, J = 15.6 Hz, H-8b), 2.54 (3H, m, H-2b, H2-15), 2.71 (1H, dd, J = 16.6, 3.3 Hz, H-25a), 2.79
(1H, dd, J = 16.6, 11.2 Hz, H-25b), 3.75 (2H, m, H2-27), 3.88 (1H, tt, J = 8.1, 2.8 Hz, H-3), 4.15 (1H, m,
H-11), 5.01 (1H, br.s, Ph-OH), 5.18-5.22 (2H, m, H-9, H-26), 6.75 (2H, d, J = 8.5 Hz, H-18, H-20), 7.06
(2H, d, J = 8.4 Hz, H-17, H-21); 13C NMR $ (500 MHz, CDCl3, 0.017 M) ppm: 21.20 (C-22 or 23), 24.62
(C-13), 25.18 (C-8), 25.93 (C-22 or 23), 27.29 (C-4), 31.43 (C-14), 34.58 (C-12), 34.75 (C-15), 34.96
(C-10), 35.48 (C-5), 36.90 (C-25), 37.03 (C-6), 42.73 (C-2), 63.77 (C-11), 64.44 (C-27), 68.81 (C-9),
70.58 (C-3), 71.80 (C-26), 100.26 (C-7), 115.06 (2C, C-18, C-20), 129.49 (2C, C-17, C-21), 135.10
1
(C-16), 153.51 (C-19), 169.63 (C-24), 171.57 (C-1). These NMR signals were assigned by H-1H
COSY, HSQC, and HMBC. HR-FAB-MS (matrix: 3-nitrobenzyl alcohol): m/z 491.2649 (MH+, calcd
for C27H39O8, 491.2645).
To a solution of the phosphonium bromide 24 (27.0 mg, 0.042 mmol, 11.0 equiv.) in THF (0.5 mL) was
added 1.6 M n-BuLi in hexane (20 µL, 0.032 mmol, 8.4 equiv.) at 4 °C. After stirring for 30 min at the
same temperature, a portion of the mixture (0.25 mL) was added to a solution of the aldehyde 22 (1.7 mg,
3.5 µmol) in THF (0.15 mL) at ꢀ78°C. The mixture was stirred for 1.5 h at the same temperature, and
warmed at !10 °C. After 1.5 h of stirring at !10 °C, the mixture was diluted with EtOAc (1.0 mL), and
the reaction was quenched with saturated aq. NH4Cl (2.5 mL). The organic layer was separated, and the
aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried
over Na2SO4, filtered, and concentrated in vacuo. The residue was purified by column chromatography
(silica gel, 20% EtOAc/hexane) to afford 26 (1.1 mg, 1.4 µmol, 41%) as clear oil. Compound 26:
1
E-Alkene, H NMR $ (400 MHz, CDCl3, 0.004 M) ppm: 0.88 (3H, s), 1.02 (3H, s), 1.33-1.68 (9H, m),
2.25-2.52 (5H, m), 2.70 (1H, dd, J = 6.5, 3.0 Hz), 2.86 (1H, dd, J = 11.4, 3.5 Hz), 3.56 (2H, m), 3.85 (1H,
m), 4.22 (1H, m), 4.44 (1H, d, J = 12.0 Hz), 4.53 (1H, d, J = 12.0 Hz), 5.02 (4H, s), 5.20 (2H, m), 6.27
1
(1H, dt, J = 15.9, 7.0 Hz), 6.72-6.86 (3H, m), 6.94-7.44 (16H, m); Z-Alkene, H NMR $ (400 MHz,
CDCl3, 0.004 M) ppm: 0.82 (3H, s), 0.95 (3H, s), 1.33-1.68 (9H, m), 2.25-2.52 (5H, m), 2.74 (1H, dd, J =
6.5, 3.0 Hz), 2.90 (1H, dd, J = 11.4, 3.5 Hz), 3.56 (2H, m), 3.85 (1H, m), 4.22 (1H, m), 4.48 (1H, d, J =
12.0 Hz), 4.56 (1H, d, J = 12.0 Hz), 5.02 (2H, s), 5.04 (2H, s), 5.20 (2H, m), 5.75 (1H, dt, J = 11.8, 7.3
Hz), 6.57 (1H, J = 11.8 Hz), 6.72-6.86 (2H, m), 6.94-7.44 (16H, m); HR-FAB-MS (matrix: 3-nitrobenzyl
alcohol): m/z 774.3740 (M+, calcd for C48H54O9, 774.3768).
To a solution of 26 (2.5 mg, 3.2 µmol) in EtOAc (0.45 mL) and MeOH (0.45 mL) was added Pd(OH)2/C
(1.0 mg, 40% w/w). The mixture was vigorously stirred under an H2 atmosphere for 2.5 h. The
reaction mixture was filtered and concentrated in vacuo. The residue was purified by column
chromatography (silica gel, 70% EtOAc/hexane) to afford 5 (1.6 mg, 3.2 µmol, quant.) as clear oil.

HETEROCYCLES, Vol. 86, No. 1, 2012
299
1
Compound 5: [!]D +53.7° (c 0.14, CHCl3, 12.4 °C); H NMR $ (400 MHz, CDCl3, 0.006 M) ppm: 0.87
(3H, s, H3-22 or 23), 0.94 (3H, s, H3-22 or 23), 1.41 (7H, m, H2-4, H2-5, H-10a, H-12a, H-13a), 1.50-1.76
(6H, m, H-8a, H-10b, H-12b, H-13b, H2-14), 2.31 (1H, t, J = 6.0 Hz, 27-OH), 2.39-2.64 (5H, m, H2-2,
H-8b, H2-15), 2.78 (2H, m, H2-25), 3.77 (2H, m, H2-27), 3.91 (1H, tt, J = 10.7, 3.1 Hz, H-3), 4.27 (1H, m,
H-11), 4.89 (1H, s, 17-OH), 5.20 (2H, m, H-9, H-26), 5.75 (1H, s, 20-OH), 6.57 (1H, dd, J = 8.5, 3.0 Hz,
13
H-19), 6.69 (1H, d, J = 8.5 Hz, H-18), 6.76 (1H, d, J = 2.9 Hz, H-21); C NMR $ (125 MHz, CDCl3,
0.006 M) ppm: 21.16 (C-22 or 23), 24.13 (C-13), 25.25 (C-8), 25.91 (C-22 or 23), 27.25 (C-4), 27.72
(C-14), 29.20 (C-15), 34.28 (C-12), 34.55 (C-5), 35.04 (C-10), 36.95 (C-6), 37.07 (C-25), 42.88 (C-2),
62.63 (C-11), 64.17 (C-27), 68.93 (C-9), 70.63 (C-3), 72.49 (C-26), 100.44 (C-7), 113.12 (C-19), 116.42
(C-21), 116.63 (C-18), 130.29 (C-16), 147.19 (C-17), 150.52 (C-20), 169.42 (C-24), 172.99 (C-1).
1
These NMR signals were assigned by H-1H COSY, HSQC, and HMBC. HR-FAB-MS (matrix:
glycerol): m/z 506.2508 (M+, calcd for C27H38O9, 506.2516).
Synthesis of 1. To a solution of 2-benzyloxybenzyl bromide (163 mg, 0.588 mmol) in toluene (8.5 mL)
was added PPh3 (216 mg, 0.824 mmol, 1.4 equiv.) and heated to 110 °C. After 12.5 h of stirring at the
same temperature, the reaction mixture was kept in a freezer at –20 °C for 1 h. The mixture was filtered
and washed well with hexane to yield (3-benzyloxybenzyl)triphenylphosphonium bromide (310 mg, 0.59
mmol, quant.) as a white solid. (3-Benzyloxybenzyl)triphenylphosphonium bromide: mp. 228-233 °C;
1H NMR $ (500 MHz, CDCl3, 0.33 M) ppm: 4.78 (2H, s), 5.37 (2H, d, J = 14.4 Hz), 6.66 (1H, d, J = 7.5
Hz), 6.85 (2H, m), 7.02 (1H, t, J = 7.9 Hz), 7.33 (5H, m), 7.60 (6H, m), 7.75 (9H, m); HR-FAB-MS
(matrix: 3-nitrobenzyl alcohol): m/z 459.1881 ([M–Br]+, calcd for C32H28OP, 459.1878).
To a solution of the phosphonium bromide (19.0 mg, 0.035 mmol, 5.7 equiv.) in THF (9 mL) was added
1.6 M n-BuLi in hexane (20 µL, 0.035 mmol, 5.2 equiv.) at 4 °C. After 30 min of stirring at the same
temperature, a portion of the mixture (0.52 mL) was added to the aldehyde 22 (3.0 mg, 6.2 µmol) at
–78 °C. The mixture was stirred for 2 h at the same temperature and warmed at 4 °C. After 4 h of
stirring at 4 °C, the reaction mixture was diluted with EtOAc (1.0 mL) and the reaction was quenched
with saturated aq. NH4Cl (2.5 mL). The organic layer was separated, and the aqueous layer was
extracted with EtOAc. The combined organic layers were washed with brine, dried over Na2SO4,
filtered, and concentrated in vacuo. The residue was purified by column chromatography (silica gel,
25% EtOAc/hexane) to afford a mixture of alkenes (1.0 mg, 1.5 µmol). To a solution of the alkenes (2.0
mg, 3.0 µmol) in EtOAc (0.5 mL) and MeOH (0.5 mL) was added Pd(OH)2/C (1.0 mg, 0.5 equiv. w/w).
The mixture was vigorously stirred under an H2 atmosphere for 6 h. The reaction mixture was filtered
and concentrated in vacuo. The residue was purified by column chromatography (silica gel, 40%
EtOAc/hexane) to afford 1 (1.5 mg, 3.1 µmol, 25% in 2 steps) as clear oil. Compound 1: [!]D +43.6° (c
0.15, CHCl3, 15.7 °C: lit.,15 +47°); 1H NMR and FAB-MS data coincided with those reported previously.15

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Inhibition of specific binding of [3H]PDBu to PKC C1 peptides. The binding of [3H]PDBu to the
PKC C1 peptides (!-C1A, $-C1A, and $-C1B) was evaluated by the procedure of Sharkey and
Blumberg27 with slight modifications as reported previously28 with 50 mM Tris-maleate buffer (pH 7.4 at
4 °C), 10 – 40 nM each PKC C1 peptide, 20 nM [3H]PDBu (19.6 Ci/mmol), 50 µg/mL 1,2-dioleoyl-sn-
glycero-3-phospho-L-serine (Sigma), 3 mg/mL bovine ! -globulin (Sigma), and various concentrations of
inhibitors. Binding affinity was evaluated on the basis of the concentration required to cause 50%
inhibition of the specific binding of [3H]PDBu, IC50, which was calculated with Microsoft Excel. The
inhibition constant, Ki, was calculated by the method of Sharkey and Blumberg.27
Anti-proliferative activity against a panel of 39 human cancer cell lines. A panel of 39 human
cancer cell lines established by Yamori and coworkers32 according to the NCI method with modifications
was employed, and cell growth inhibitory activity was measured as reported previously.32 In brief, the
cells were plated in 96-well plates in RPMI 1640 medium supplemented with 5% fetal bovine serum and
allowed to attach overnight. The cells were incubated with each test compound for 48 h. Cell growth
was estimated by the sulforhodamine B assay. The 50% growth inhibition (GI50) parameter was
calculated as reported previously.32 Absorbance for the control well (C) and the test well (T) were
measured at 525 nm along with that for the test well at time 0 (T0). Cell growth inhibition (% growth)
by each concentration of drug (10–8, 10–7, 10–6, 10–5, and 10–4 M) was calculated as 100[(T - T0)/(C - T0)]
using the average of duplicate points. By processing these values, each GI50 value, defined as 100[(T -
T0)/(C - T0)] = 50, was determined.
EBV-EA induction test. Human B-lymphoblastoid Raji cells (5 " 105 / mL) were incubated at 37 °C
under a 5% CO2 atmosphere in 1 mL of RPMI 1640 medium (supplemented with 10% fetal bovine
serum) with 4 mM sodium n-butyrate (a synergist) and 10, 100, or 1000 nM of each test compound for
the induction test, or 100 nM of each test compound in the presence of 32 nM of TPA for the inhibition
test. In the induction test, each test compound was added as 2 µL of a DMSO solution (5, 50, and 500
µM stock solution) along with 2 µL DMSO; the final DMSO concentration was 0.4%. In the inhibition
test, TPA was added as 2 µL of a DMSO solution (16 µM stock solution), 10 min after the addition of
each test compound (2 µL of a DMSO solution: 50 µM). After incubation for 48 h, smears were made
from the cell suspension, and the EBV-EA-expressing cells were stained by a conventional indirect
immunofluorescence technique with an NPC patient's serum (a gift from Kobe University) and
FITC-labeled anti-human IgG (DAKO, Glostrup, Denmark) as reported previously.33,34 In each assay, at
least 500 cells were counted and the proportion of the EA-positive cells was recorded. Cell viability
exceeded 60% in each experiment.

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ACKNOWLEDGEMENTS
This work was supported by a Grant-in-Aid for Scientific Research on Innovative Areas “Chemical
Biology of Natural Products” (No. 23102011 to K.I.) from The Ministry of Education, Culture, Sports,
Science and Technology, Japan. We also thank the Screening Committee for Anticancer Drugs
supported by a Grant-in-aid for Scientific Research on Innovative Areas “Scientific Support Programs for
Cancer Research” from The Ministry of Education, Culture, Sports, Science and Technology, Japan.
This study was partly carried out with the JEOL JMS-700 MS spectrometer in the Joint Usage/Research
Center (JURC) at the Institute for Chemical Research, Kyoto University.
REFERENCES
1. Y. Nishizuka, Nature, 1984, 308, 693; Y. Nishizuka, FASEB J., 1995, 9, 484.
2. A. C. Newton, Chem. Rev., 2001, 101, 2353.
3. Y. Kishi and R. R. Rando, Acc. Chem. Res., 1998, 31, 163.
4. G. R. Pettit, C. L. Herald, D. L. Doubek, D. L. Herald, E. Arnold, and J. Clardy, J. Am. Chem. Soc.,
1982, 104, 6846.
5. M. Gschwendt, G. Fürstenberger, S. Rose-John, M. Rogers, W. Kittstein, G. R. Pettit, C. L. Herald,
and F. Marks, Carcinogenesis, 1988, 9, 555.
6. J. D. Winegarden, A. M. Mauer, T. F. Gajewski, P. C. Hoffman, S. Krauss, C. M. Rudin, and E. E.
Vokes, Lung Cancer, 2003, 39, 191; M. L. Varterasian, R. M. Mohammad, M. S. Shurafa, K.
Hulburd, P. A. Pemberton, D. H. Rodriguez, V. Spadoni, D. S. Eilender, A. Murgo, N. Wall, M. Dan,
and A. M. Al-Katib, Clin. Cancer Res., 2000, 6, 825.
7. T. J. Nelson and D. L. Alkon, Trends Biochem. Sci., 2009, 34, 136.
8. R. Mehla, S. Bivalkar-Mehla, R. Zhang, I. Handy, H. Albrecht, S. Giri, P. Nagarkatti, M. Nagarkatti,
and A. Chauhan, PLoS One, 2010, 5, e11160.
9. R. Mutter and M. Wills, Bioorg. Med. Chem., 2000, 8, 1841.
10. B. M. Trost and G. Dong, Nature, 2008, 456, 485; G. E. Keck, Y. B. Poudel, T. J. Cummins, A.
Rudra, and J. A. Covel, J. Am. Chem. Soc., 2011, 133, 744; P. A. Wender and A. J. Schrier, J. Am.
Chem. Soc., 2011, 133, 9228.
11. D. Schaar, L. Goodell, J. Aisner, X. X. Cui, Z. T. Han, R. Chang, J. Martin, S. Grospe, L. Dudek, J,
Riley, J. Manago, Y. Li, E. H. Rubin, A. Conney, and R. K. Strair, Cancer Chemother. Pharmacol.,
2006, 57, 789.
12. A. P. Kozikowski, Y. Chen, T. Subhasish, N. E. Lewin, P. M. Blumberg, Z. Zhong, M. A.
D'Annibale, W. L. Wang, Y. Sheng, and B. Langley, ChemMedChem, 2009, 4, 1095.
13. S. Zayed, B. Sorg, and E. Hecker, Planta Med., 1984, 50, 65; Z. Szállási, L. Krsmanovic, and P. M.

302
HETEROCYCLES, Vol. 86, No. 1, 2012
Blumberg, Cancer Res., 1993, 53, 2507.
14. K. R. Gustafson, J. H. Cardellina, II, J. B. McMahon, R. J. Gulakowski, J. Ishitoya, Z. Szallasi, N. E.
Lewin, P. M. Blumberg, O. S. Weislow, J. A. Beutler, R. W. Buckheit, G. M. Cragg, P. A. Cox, J. P.
Bader, and M. R. Boyd, J. Med. Chem., 1992, 35, 1978.
15. Y. Nakagawa, R. C. Yanagita, N. Hamada, A. Murakami, H. Takahashi, N. Saito, H. Nagai, and K.
Irie, J. Am. Chem. Soc., 2009, 131, 7573.
16. P. J. Reddig, N. E. Dreckschmidt, H. Ahrens, R. Simsiman, C.-P. Tseng, J. Zou, T. D. Oberley, and
A. K. Verma, Cancer Res., 1999, 59, 5710.
17. Z. Lu, A. Hornia, Y.-W. Jiang, Q. Zang, S. Ohno, and D. A. Foster, Mol. Cell Biol., 1997, 17, 3418.
18. R. C. Yanagita, H. Kamachi, K. Tanaka, A. Murakami, Y. Nakagawa, H. Tokuda, H. Nagai, and K.
Irie, Bioorg. Med. Chem. Lett., 2010, 20, 6064.
19. G. Zhu and E. Negishi, Org. Lett., 2007, 9, 2771.
20. H. Hanawa, D. Uraguchi, S. Konishi, T. Hashimoto, and K. Maruoka, Chem. Eur. J., 2003, 9, 4405.
21. J. J. W. Duan and A. B. Smith, III, J. Org. Chem., 1993, 58, 3703.
22. S. V. Ley, J. Norman, W. P. Griffith, and S. P. Marsden, Synthesis, 1994, 639.
23. D. A. Evans, B. W. Trotter, P. J. Coleman, B. Côté, L. C. Dias, H. A. Rajapakse, and A. N. Tyler,
Tetrahedron, 1999, 55, 8671.
24. G. Solladie and J. Hutt, Tetrahedron Lett., 1987, 28, 797.
25. B. S. Bal, W. E. Childers, Jr., and H. W. Pinnick, Tetrahedron, 1981, 37, 2091.
26. J. Inanaga, K. Hirata, H. Saeki, T. Katsuki, and M. Yamaguchi, Bull. Chem. Soc. Jpn., 1979, 52,
1989.
27. N. A. Sharkey and P. M. Blumberg, Cancer Res., 1985, 45, 19.
28. K. Irie, K. Oie, A. Nakahara, Y. Yanai, H. Ohigashi, P. A. Wender, H. Fukuda, H. Konishi, and U.
Kikkawa, J. Am. Chem. Soc., 1998, 120, 9159; M. Shindo, K. Irie, A. Nakahara, H. Ohigashi, H.
Konishi, U. Kikkawa, H. Fukuda, and P. A. Wender, Bioorg. Med. Chem., 2001, 9, 2073.
29. K. Bögi, P. S. Lorenzo, Z. Szállási, P. Ács, G. S. Wagner, and P. M. Blumberg, Cancer Res., 1998,
58, 1423.
30. A. M. Jeffrey and R. M. J. Liskamp, Proc. Natl. Acad. Sci. U. S. A., 1986, 83, 241.
31. P. A. Wender, J. L. Baryza, C. E. Bennett, F. C. Bi, S. E. Brenner, M. O. Clarke, J. C. Horan, C. Kan,
E. Lacôte, B. Lippa, P. G. Nell, and T. M. Turner, J. Am. Chem. Soc., 2002, 124, 13648.
32. T. Yamori, A. Matsunaga, S. Sato, K. Yamazaki, A. Komi, K. Ishizu, I. Mita, H. Edatsugi, Y.
Matsuba, K. Takezawa, O. Nakanishi, H. Kohno, Y. Nakajima, H. Komatsu, T. Andoh, and T.
Tsuruo, Cancer Res., 1999, 59, 4042.
33. Y. Ito, S. Yanase, J. Fujita, T. Harayama, M. Takashima, and H. Imanaka, Cancer Lett., 1981, 13,

HETEROCYCLES, Vol. 86, No. 1, 2012
303
29.
34. H. zur Hausen, G. W. Bornkamm, R. Schmidt, and E. Hecker, Proc. Natl. Acad. Sci. U. S. A., 1979,
76, 782.
35. I. Ohtani, T. Kusumi, Y. Kashman, and H. Kakisawa, J. Am. Chem. Soc., 1991, 113, 4092.
36. M. C. Carreño, R. D. Mazery, A. Urbano, F. Colobert, and G. Solladié, J. Org. Chem., 2003, 68,
7779.