Total synthesis of FR901464: Second generation

Article abstract of DOI:10.1016/j.tet.2005.11.031

FR901464, a potent cell cycle inhibitor, was synthesized in a convergent manner using natural chiral pool, l-threonine, ethyl (S)-lactate and 2-deoxy-d-glucose as starting materials.

Full text of DOI:10.1016/j.tet.2005.11.031

Tetrahedron 62 (2006) 1378–1389
Total synthesis of FR901464: second generation
*
Hajime Motoyoshi, Masato Horigome, Hidenori Watanabe and Takeshi Kitahara
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo,
1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
Received 2 July 2005; revised 16 November 2005; accepted 16 November 2005
Available online 13 December 2005
Abstract—FR901464, a potent cell cycle inhibitor, was synthesized in a convergent manner using natural chiral pool, L-threonine, ethyl
(S)-lactate and 2-deoxy-D-glucose as starting materials.
q 2005 Published by Elsevier Ltd.
1. Introduction
block was prepared using asymmetric catalysts.5 In contrast,
we decided to synthesize all of the segments taking full
advantage of materials from the chiral pool.3 Segment A
would be prepared from commercially available ethyl (S)-
lactate, and segment C would be synthesized from 2-deoxy-
D-glucose. Segment B, in which all the substituents on the
tetrahydropyran ring are cis-oriented, would be synthesized
by stepwise carbon chain elongation via D and E starting
from Garner’s aldehyde6 derived from L-threonine.
FR901464 (1), which has two highly functionalized
tetrahydropyran rings linked by a diene chain (Fig. 1), was
isolated from the culture broth of bacterium Pseudomonas
sp. no. 2663.1 This compound shows transcriptional
regulating activity and induces characteristic G1 and G2/M
phase arrest in the cell cycle. Related to these activities, it
also exhibits a potent antitumor effect. The absolute
configuration of 1, which was initially ambiguous, was
elucidated by spectroscopic and chemical analysis.2 Its
unique structure as well as the significant biological activities
prompted us to undertake the synthesis of this compound.
We have previously communicated a synthesis of 1,3 and
also the synthesis of biotinylated FR901464.4 In this paper,
we wish to describe a new, improved synthesis of 1.
In our first generation synthesis,3 we encountered difficul-
ties at the assembly stage (Scheme 2). For example,
(a) lower yield in Julia olefination (33%), (b) recycling-
demanding acetylation due to impossibility of either
selective removal of the TBDPS group from 4 or selective
acetylation of the corresponding diol and, most importantly,
(c) poor regioselectivity in epoxidation of 5. Initially, we
planned to construct the epoxide moiety on the right
tetrahydropyran ring in the end of the synthesis because it
was thought to be highly sensitive. However, concomitant
epoxidation of the conjugated diene occurred in every
reaction condition (mCPBA, DMDO, Sharpless’ con-
ditions,7 etc.) to give 7 and/or diepoxy compounds, and
consequently lowered chemical yields of 6 (w23%).
Similar results were also obtained by Jacobsen et al.,5 and
we concluded that this side-reaction came from extraordi-
narily high reactivity of the diene and was essentially
inevitable. In the second generation synthesis, therefore, we
decided to install epoxide moiety in the segment C prior to
coupling reaction. Other key modifications included (a) the
use of a modified Julia olefination8 employing benzothia-
zolyl sulfone, and (b) replacing TBDPS group on the
segment A with TBS group so as to allow removal of one of
the silyl groups selectively and thus avoid a complicated
acetylation–deacetylation sequence to obtain the mono-
acetate derivative.
19
17
16
5'
OAc
O
O
11
O
1
5
OH
1'
N
H
HO
20
O
18
FR901464 (1)
Figure 1.
Our basic synthetic strategy is illustrated in Scheme 1. From
a synthetic perspective, we sought an efficient and
convergent approach to our target, and decided upon
disconnections at the diene and amide bonds generating
segments A, B and C (or C0). Recently, Jacobsen et al.
reported a total synthesis of 1 in which every chiral building
Keywords: FR901464; Asymmetric synthesis; Coupling reactions; Cell
cycle inhibitor.
Corresponding author. Fax: C81 3 5841 8019;
e-mail: kitahara-t@kitasato.or.jp
*
0040–4020/$ - see front matter q 2005 Published by Elsevier Ltd.
doi:10.1016/j.tet.2005.11.031

H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
1379
O
O
OHC
R'O
O
OHC
R'O
O
O
S
OR
CO2H
OMe
Ar
OMe
1
+
+
H2N
OH
O
A
B
C
C'
O
OH
HO
HO
C
A
CO2Et
Ethyl (S)-lactate
OH
2-Deoxy-D-glucose
CHO
O
O
O
CO2Me
O
B
L-Threonine
NBoc
BocHN
BocHN
Garner's aldehyde
D
E
Scheme 1. Synthetic plan for FR901464.
OTBDPS
OHC
Ts
O
O
O
Julia coupling
33%
OMe
+
TBSO
N
H
2
3
OTBDPS
O
O
1) xs TBAF 2) xs Ac2O
3) LiOH
O
OAc
O
O
O
OMe
OMe
71%, after recycling (x2)
N
H
4
TBSO
N
H
HO
5
O
OAc
O
O
O
OAc
O
O
O
epoxidation
23%
OMe
OMe
N
HO
N
H
HO
H
O
6
7
Scheme 2. Problems in our first generation synthesis.
The synthesis of segment B is shown in Scheme 3. Garner’s
aldehyde6 was subjected to a Wittig reaction followed by
hydrogenation to give an inseparable 2:1 mixture of
diastereoisomers. In this hydrogenation step, high stereo-
selectivity as described in the literature9 was not observed.
This mixture was converted under general acidic conditions
into lactone 11, which was then treated with Lawesson’s
reagent10 affording thionolactone 12. Although complete
epimerization of the stereocenter a to the thiocarbonyl was
observed, this was of no consequence (vide infra). In order
to install the other carbon chain, we attempted a Wittig
reaction on thionolactone 12, and fortunately, the desired
ester 13 was obtained in high yield. To the best of our
knowledge, this is the first example of a successful Wittig
reaction on a thionolactone.11 Deconjugation of a,b-
unsaturated ester 13 was performed with DBU to furnish
dihydropyran 14. The double bond of 14 was stereoselec-
tively hydrogenated with platinum oxide to give the desired
all-cis isomer 15 (70%) along with unassigned polar by-
products. No other stereoisomers were detected and the
stereochemistry of 15 was confirmed by an NOE experiment
(see Section 2). The ester moiety of 15 was reduced to an
aldehyde with DIBAL and a three-carbon chain was added
by the Wittig reaction. The resultant ethyl ester 17 was then
reduced to alcohol 18. This allylic alcohol 18 was converted
into benzothiazolyl sulfide 19 by Mitsunobu’s method,12
and then mildly oxidized with molybdenum catalyst13 to
afford sulfone 20 in excellent yield. Acid treatment of 20
liberated the amino group to give 21, which was used in the
next reaction without purification.
The synthesis of segment A is displayed in Scheme 4.
The known ester 22,14,15 derived from ethyl (S)-lactate via
the (Z)-selective Still–Gennari modification of the
Horner–Emmons reaction,15 was hydrolyzed to furnish
a,b-unsaturated carboxylic acid 23.
To synthesize segment C, 2-deoxy-D-glucose was first
transformed into known triol 2416 in five steps (Scheme 5).
Protection of the 1,3-diol as a p-methoxybenzylidene acetal
furnished alcohol 25.17 Dess–Martin oxidation18 followed
by Tebbe methylenation19 gave exo-olefin 27. Cleavage of
the p-methoxybenzylidene acetal with DIBAL generated
a primary alcohol 28, which in turn was protected as its
pivalate ester. After removal of PMB group with DDQ,20
hydroxyl group-directed epoxidation of 30 with mCPBA
proceeded stereoselectively to give the desired epoxide 31.
Silylation of 31 under usual conditions (TBSOTf or TBSCl

1380
H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
CHO
NBoc
CO2Et
CO2Et
Ph3P=C(Me)CO2Et
H2, Pd(OH)2/C
CSA, MeOH
12 h, 92%
O
O
O
NBoc
NBoc
2-propanol, 24 h
95%
benzene, reflux, 95%
Garner's aldehyde
8
9
(2:1 mixture)
OH
O
S
O
O
Ph3P=CHCO2Me
Lawesson's reagent
CSA, benzene
88%
CO2Me
toluene, 80 °C, 24 h
E/Z = 19:81, 81%
toluene, 80 °C, 65%
BocHN
BocHN
BocHN
10
12
11
1) H2, PtO2, AcOH
5 atm, 36 h, 70%
O
O
O
R
CO2Me
CO2Me
DBU, benzene
reflux, 6 h, quant. BocHN
2) DIBAL, toluene
–78 °C, 98%
BocHN
BocHN
13
14
15: R = CO2Me
16: R = CHO
O
1) Ph3P=C(Me)CO2Et, benzene
60 °C, 3 h, E/Z = 23:1, 93%
1) 2-mercaptobenzothiazole
DIAD, PPh3, THF, 96%
R
BocHN
2) DIBAL, toluene, –68 to 0 °C, 99%
2) (NH4)6Mo7O24·4H2O
H2O2, EtOH, 87%
17: R = CO2Et
18: R = CH2OH
O
O
S
S
N
O
X
O
S
4 N HCl/EtOAc
N
BocHN
H2N
19: X = S
20: X = SO2
21
Scheme 3. Synthesis of segment B.
OH
OTBS
OTBS
CO2H
23
ref. 14, 15
LiOH, MeOH-H2O
91%
CO2Et
Ethyl (S)-lactate
Scheme 4. Synthesis of segment A.
CO2Me
22
O
O
OH
O
p-MeOC6H4CH(OMe)2
ref. 16
HO
HO
HO
HO
O
OMe
OMe
TsOH, DMF, 60 °C
reduced pressure, 84%
PMP
OMe
O
OH
24
OH
OH
25
2-Deoxy-D-glucose
O
X
O
1) Dess-Martin periodinane
pyridine, CH2Cl2, 95%
1) DIBAL, CH2Cl2
–15 °C, 91%
O
RO
OMe
DDQ, CH2Cl2, H2O
PMP
O
PMBO
0 °C, 92%
2) Tebbe reagent, pyridine
THF, –20 °C, 94%
2) PivCl, DMAP, NEt3
CH2Cl2, 95%
26: X = O
27: X = CH2
28: R = H
29: R = Piv
O
O
PivO
O
TBSCN, DMF, 70 °C
PivO
HO
mCPBA, NaHCO3
CH2Cl2, 84%
PivO
OMe
OMe
OMe
70% (91% based on
recovery)
HO
TBSO
O
O
30
31
32
O
OHC
TBSO
O
HO
TPAP, NMO
CH2Cl2, ~80%
DIBAL, THF
–40 ˚C, 91%
OMe
OMe
TBSO
O
O
33
34
Scheme 5. Synthesis of segment C.

H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
1381
O
O
S
N
OTBS
O
O
S
LHMDS, 34, THF
–78 °C to rt, 68%
HBTU, N-ethylmorpholine
21
23
+
CH3CN, 83% (2 steps from 20)
N
H
35
1) 0.025% HCl/MeOH
–20 °C, 85%
OTBS
O
O
O
OR
O
O
O
OMe
OMe
2) Ac2O, NEt3
DMAP, CH2Cl2, 98%
N
TBSO
N
TBSO
O
H
H
O
37: R = H
38: R = Ac
36
Amberlyst 15, THF, H2O
then HPLC purification
OAc
O
O
O
TBAF, THF
1
OMe
–10 to 0 °C, 97%
36% (45% based on recovery)
N
HO
O
H
6
Scheme 6. Completion of the synthesis of FR901464.
in the presence of bases) gave only low yields, probably
because the Lewis acidity of these reagents was incompa-
tible with the labile epoxide of 31. On the other hand,
t-butyldimethylsilyl cyanide (TBSCN) was found to be a
mild and effective silylating agent21 and afforded satisfac-
tory yield (91% based on recovered 31). Removal of
pivaloyl group was successfully achieved with DIBAL in
tetrahydrofuran as a solvent. When this reaction was
executed in dichloromethane, reductive opening of the
epoxide was observed even when stoichiometric amounts of
DIBAL were used. We postulate that tetrahydrofuran
solvated DIBAL and attenuated its reactivity to some
degree. Finally, primary alcohol 33 was oxidized to
aldehyde 34 by TPAP–NMO22 in good yield.
to the synthetic strategy. We have also synthesized biotin-
labeled FR9014644 utilizing information gained from these
synthetic studies. With increasing attention focused on this
compound owing to its remarkable biological activity, our
work may offer access to materials of value in these related
fields.
2. Experimental
2.1. General
All of the solvents for non-aqueous reactions were dried
before use. Benzene, toluene and THF were distilled from
sodium benzophenone ketyl. Dichloromethane was distilled
from phosphorus pentoxide. Acetonitrile and DMF were
With these segments in hand, we set about the final coupling
reactions (Scheme 6). Sulfone 35 was obtained from amine
21 and carboxylic acid 23 using HBTU.23 Modified Julia
olefination8 with sulfone 35 and epoxyaldehyde 34
proceeded smoothly in a highly E-selective manner to
furnish the desired diene 36 in 68% yield,24 and with no
observable side-reactions at the epoxide. Selective desilyla-
tion of 36 was achieved with a highly dilute solution
(0.025%) of hydrochloric acid in methanol without any
obvious damage to the epoxide moiety. The liberated
hydroxyl group was acetylated to furnish 38 under standard
conditions, and then the remaining TBS group was cleanly
removed with TBAF. Interestingly, this methylated
FR901464 (6) exhibited more powerful biological activity
than that of natural 1, which was thought to come from its
greater stability of methyl acetal in contrast to the labile
hemiacetal of 1.3,4 The final hydrolysis of the methyl acetal
moiety proved to be a most difficult problem because of
extremely high sensitivity of 1 to acidic conditions.4
However, after substantial investigation, we found that
Amberlyst 15 in wet THF gave the target molecule 1 as a
single isomer, albeit in moderate yield. As a result of this
revised synthetic route, we were able to realize an efficient
and straightforward synthesis of FR901464.
˚
dried over molecular sieves (4 A). Methanol was dried over
˚
molecular sieves (3 A). Optical rotations were recorded
with a JASCO DIP-1000 polarimeter. IR spectra were
measured with a JASCO FT/IR-230 spectrophotometer.
1H and 13C NMR were recorded on JEOL JNM AL300,
Bruker AC-300, or JEOL JNM-A500. Mass spectra were
recorded on JEOL JMS-700T. Column chromatography was
performed using Merck silica gel 60 (0.060–0.200 mm).
TLC was carried out on Merck glass plates precoated with
silica gel 60 F254 (0.25 mm). HPLC was performed using
SHOWA DENKO shodex DS-4 equipped with Senshu Pak
PEGASIL ODS (4.6f!250 mm), Senshu Pak PEGASIL
ODS (20f!250 mm), Senshu Pak Silica-1251-N (4.6f!
250 mm) or Senshu Pak silica-5251-N (20f!250 mm),
respectively.
2.1.1. t-Butyl (10E,4R,5R)-4-(30-ethoxy-20-methyl-30-
oxoprop-10-en-10-yl)-2,2,5-trimethyl-1,3-oxazolidine-3-
carboxylate (8). To a solution of Garner’s aldehyde derived
from L-threonine (50 mg, 0.206 mmol) in benzene (2 mL)
was added (carbethoxyethylidene)triphenylphosphorane
(82 mg, 0.226 mmol) and the mixture was stirred for
30 min at room temperature and then heated under reflux
for 4 h. The solvent was removed under reduced pressure.
The residue was purified by silica gel column chromato-
graphy (9:1 hexanes/EtOAc) to provide 8 as a colorless oil
(64 mg, 95%); nD27Z1.4602; [a]D25 C17.7 (c 0.45, CHCl3);
In conclusion, we have accomplished a second generation
total synthesis of FR901464 using materials derived from
the natural chiral pool. Problems encountered in our
first generation synthesis were solved by several revisions
IR (film): nmax 1703, 1658 cmK1 1H NMR (300 MHz,
;

1382
H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
CDCl3): d (ppm) 1.27 (3H, d, JZ6.0 Hz, 5-CH3), 1.29 (3H,
t, JZ7.1 Hz, CH3 of –CO2Et), 1.35 (9H, s, tBu), 1.55, 1.61
(6H, two s, 2-CH3), 1.89 (3H, s, 20-CH3), 3.86 (1H, dq,
JZ6.0, 8.3 Hz, 5-H), 4.0–4.15 (1H, m, 4-H), 4.20 (2H, q,
JZ7.1 Hz, CH2 of –CO2Et), 6.48 (1H, d, JZ8.4 Hz, 10-H);
13C NMR (75.5 MHz, CDCl3): d (ppm) 12.4, 14.0, 17.1,
25.0, 25.9, 27.9, 60.3, 61.8, 74.2, 79.4, 94.1, 128.6, 140.1,
151.4, 167.1. Anal. Calcd for C17H29NO5: C, 62.36; H, 8.93;
N, 4.28. Found: C, 62.39; H, 8.93; N, 4.48.
separation. However, a small amount of this mixture was
further purified and separated by preparative TLC (1:1
hexanes/EtOAc) for analytical purposes.
(2R,4R,5R)-4-t-Butoxycarbonylamino-2-methylhexan-5-
olide (11a, minor isomer, less polar). Mp 140–144 8C; [a]D25
C46.1 (c 0.45, CHCl3); IR (KBr): nmax 3394, 1712,
1
1514 cmK1; H NMR (300 MHz, CDCl3): d (ppm) 1.32
(3H, d, JZ6.9 Hz, 2-CH3), 1.33 (3H, d, JZ6.5 Hz, 6-H),
t
1.45 (9H, s, Bu), 1.75 (1H, ddd, JZ3.3, 12.0, 13.8 Hz,
2.1.2. t-Butyl (20RS,4R,5R)-4-(30-ethoxy-20-methyl-30-
oxopropyl)-2,2,5-trimethyl-1,3-oxazolidine-3-carboxylate
(9). To a solution of 8 (20.0 g, 61.1 mmol) in 2-propanol
(100 mL) was added Pd(OH)2/C (wet, Degussa type, 2.0 g)
and the mixture was stirred for 24 h under H2 atmosphere.
The mixture was filtered through Celitew and concentrated
under reduced pressure. The residue was purified by column
chromatography on silica gel (10:1 hexanes/EtOAc) to
yield 9 as a colorless oil (19.1 g, 95%). This material was
obtained as an inseparable mixture of diastereomers (2:1);
n2D6Z1.4442; [a]D25 K23.3 (c 0.87, CHCl3); IR (film): nmax
3-Ha), 2.24 (1H, ddd, JZ3.8, 6.9, 13.8 Hz, 3-Hb), 2.61 (1H,
m, 2-H), 3.95 (1H, br, 4-H), 4.58 (1H, dq, JZ2.2, 6.5 Hz,
5-H), 4.79 (1H, br d, JZ8.7 Hz, –NH–); 13C NMR
(75.5 MHz, CDCl3): d (ppm) 17.2, 17.6, 28.3, 30.9, 34.4,
47.4, 78.7, 80.2, 155.5, 173.5. Anal. Calcd for C12H21NO4:
C, 59.24; H, 8.70; N, 5.76. Found: C, 59.31; H, 8.70; N,
5.69.
(2S,4R,5R)-4-t-Butoxycarbonylamino-2-methylhexan-5-
olide (11b, major isomer, more polar). Mp 134–139 8C;
[a]2D7 C75.2 (c 0.72, CHCl3); IR (KBr): nmax 3388, 1730,
1
1714, 1520 cmK1; H NMR (300 MHz, CDCl3): d (ppm)
1
1737, 1697 cmK1; H NMR (300 MHz, CDCl3): d (ppm)
1.17 (1H, d, JZ6.9 Hz, 20-CH3 of minor isomer), 1.19 (2H,
d, JZ6.9 Hz, 20-CH3 of major isomer), 1.24 (3H, t,
JZ7.1 Hz, CH3 of –CO2Et), 1.28 (2H, d, JZ6.3 Hz,
5-CH3 of major isomer), 1.29 (1H, d, JZ6.3 Hz, 5-CH3 of
minor isomer), 1.46 (12H, br s, 2-CH3 and tBu), 1.58 (3H, br
s, 2-CH3), 1.8–1.9, 2.1–2.25 (2H, two m, 10-H), 2.35–2.55
(1H, br, 20-H), 3.4–3.65 (1H, br, 4-H), 3.9–4.05 (1H, br,
5-H), 4.11 (2H, q, JZ7.1 Hz, CH2 of –CO2Et). Anal. Calcd
for C17H31NO5: C, 61.98; H, 9.48; N, 4.25. Found: C, 61.73;
H, 9.44; N, 4.44.
1.21 (3H, d, JZ6.3 Hz, 2-CH3), 1.34 (3H, d, JZ6.4 Hz,
6-H), 1.3–1.4 (1H, m, 3-Ha), 1.43 (9H, s, tBu), 2.5–2.7 (2H,
m, H-2, 3-Hb), 4.11 (1H, br, 4-H), 4.50 (1H, dq, JZ3.0,
6.4 Hz, 5-H), 4.75 (1H, br d, JZ8.4 Hz, –NH–); 13C NMR
(75.5 MHz, CDCl3): d (ppm) 15.5, 16.0, 28.3, 32.4, 35.5,
47.8, 75.5, 79.9, 155.5, 175.6. Anal. Calcd for C12H21NO4:
C, 59.24; H, 8.70; N, 5.76. Found: C, 59.19; H, 8.77;
N, 6.01.
2.1.5.
(3R,5R,6R)-5-t-Butoxycarbonylamino-3,6-
dimethyltetrahydropyran-2-thione (12). To a solution of
11 (38.1 g, 157 mmol) in toluene (1.2 L) was added
Lawesson’s reagent (63.3 g, 157 mmol) and the mixture
was stirred for 7 h at 80 8C and for an additional 9 h at room
temperature. The solvent was removed under reduced
pressure. Two rounds of column chromatography on silica
gel (3:1 hexanes/EtOAc first time; 2:80:20 MeOH/CHCl3/
hexanes second time) gave thionolactone 12 as a yellow
paste (26.5 g, 65%); n2D4Z1.5085; [a]2D3 C176 (c 0.50,
CHCl3); IR (film): nmax 3327, 2979, 1714, 1695, 1681, 1504,
1455, 1109, 1056, 1016 cmK1; 1H NMR (300 MHz, C6D6):
d (ppm) 0.45 (1H, ddd, JZ4.7, 14.7, 16.2 Hz, 4-Ha), 1.10
(3H, d, JZ6.1 Hz mm, 6-CH3), 1.10 (3H, d, JZ6.6 Hz,
2.1.3. Methyl (2RS,4R,5R)-4-t-butoxycarbonylamino-5-
hydroxy-2-methylhexanoate (10). To a solution of 9
(1.04 g, 3.16 mmol) in methanol (20 mL) was added D-10-
camphorsulfonic acid (79 mg, 0.316 mmol) and the mixture
was stirred for 12 h at room temperature. To the mixture was
added triethylamine (88 mL, 0.631 mmol) and the solvent
was removed under reduced pressure. The residue was
purified by column chromatography on silica gel (2:1
hexanes/EtOAc) to yield 10 as a colorless oil (0.80 g, 92%).
This material was obtained as an inseparable mixture of
diastereomers (2:1); n2D5Z1.4504; [a]2D3 C10.8 (c 0.34,
1
CHCl3); IR (film): nmax 3382, 1715, 1690 cmK1; H NMR
(300 MHz, CDCl3): d (ppm) 1.1–1.3 (6H, m, 2-CH3, 6-H),
1.42 (9H, s, Bu), 1.48–1.58, 1.83–2.04 (2H, two m, 3-H),
t
3-CH3), 1.38 (9H, s, Bu), 1.58–1.72 (2H, m, 3-H, 4-Hb),
t
3.61 (1H, dq, JZ3.6, 6.1 Hz, 6-H), 3.79 (1H, m, 5-H), 4.07
(1H, d, JZ8.7 Hz, –NH–); 13C NMR (75.5 MHz, CDCl3):
d (ppm) 15.8, 19.4, 28.2, 36.8, 41.3, 48.2, 78.7, 79.9, 155.5,
226.6; HRMS (FAB) m/z Calcd for C12H21NO3S: 259.1242
(MC). Found: 259.1215.
2.27 (1H, br s, –OH), 2.45–2.63 (1H, m, 2-H), 3.35–3.60
(1H, m, 4-H), 3.66 and 3.67 (3H, two s, –CO2Me),
3.65–3.75 (2/3H, m, 5-H of major isomer), 4.05–4.15
(1/3H, m, 5-H of minor isomer), 4.6–4.8 (1H, m, –NH–).
Anal. Calcd for C13H25NO5: C, 56.71; H, 9.15; N, 5.09.
Found: C, 56.55; H, 9.13; N, 5.18.
2.1.6. Ester 13. To a solution of 12 (25.7 g, 99 mmol) in
toluene (600 mL) was added methyl (triphenyl-
phosphoranylidene)acetate (66.3 g, 198 mmol) and the
mixture was stirred for 24 h at 80 8C. The solvent was
removed under reduced pressure. Two rounds of column
chromatography on silica gel (3:1 hexanes/EtOAc first time;
30:1–9:1 CHCl3/EtOAc second time) gave 13Z (19.4 g,
66%, colorless paste) and 13E (4.56 g, 15%, colorless
paste). Both of these compounds were used in the next
reaction.
2.1.4. d-Lactone 11. To a solution of 10 (52.1 g, 0.189 mol)
in benzene (1 L) was added D-10-camphorsulfonic acid
(1.1 g, 0.0047 mol) and the mixture was stirred for 5 h at
45 8C. The solvent was removed under reduced pressure.
The residue was purified by column chromatography on
silica gel (2:1 hexanes/EtOAc) followed by recrystallization
from hexanes–EtOAc to yield lactone 11 (40.5 g, 88%) as
colorless crystals. This material was obtained as a mixture
of diastereomers (2:1), and used in the next reaction without

H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
1383
Methyl (Z)-(3R,5R,6R)-(5-t-butoxycarbonylamino-3,6-
dimethyltetrahydropyran-2-ylidene)acetate (13Z, less
polar). n2D7Z1.4809; [a]D26 C78.5 (c 0.46, CHCl3); IR
(film): nmax 3344, 2978, 1714, 1705, 1695, 1645, 1518,
1095 cmK1; 1H NMR (300 MHz, C6D6): d (ppm) 0.51 (3H,
d, JZ6.3 Hz, 3-CH3), 0.97 (1H, ddd, JZ3.7, 12.1, 13.1 Hz,
and intact 14. This mixture was again reacted and purified
similarly to yield pure 15 as colorless crystals (3.89 g, 70%).
Stereochemistry of this compound was confirmed by an
NOE experiment; NOEs were observed between 2-H and
3-H, and between 2-H and 6-H; mp 69–71 8C; [a]2D7 K20.6
(c 0.56, CHCl3); IR (KBr): nmax 3383, 2978, 1743, 1703,
t
1
4-Ha), 1.18 (3H, d, JZ6.4 Hz, 6-CH3), 1.45 (9H, s, Bu),
1510, 1163 cmK1; H NMR (300 MHz, CDCl3): d (ppm)
1.52 (1H, ddd, JZ3.5, 5.3, 13.1 Hz, 4-Hb), 1.62 (1H, m,
3-H), 3.48 (3H, s, –OMe), 3.53 (1H, dq, JZ1.8, 6.4 Hz,
6-H), 3.68 (1H, m, 5-H), 4.67 (1H, d, JZ8.7 Hz, –NH–),
5.14 (1H, d, JZ1.2 Hz, ]CHCO2–); 13C NMR (75.5 MHz,
C6D6): d (ppm) 17.3, 17.4, 28.4, 28.9, 36.9, 48.5, 50.3, 78.0,
78.9, 99.0, 155.6, 165.1, 171.8; HRMS (FAB) m/z Calcd for
C15H25NO5: 299.1733 (MC). Found: 299.1752.
1.04 (3H, d, JZ7.5 Hz, 3-CH3), 1.13 (3H, d, JZ6.4 Hz,
6-CH3), 1.43 (9H, s, Bu), 1.81 (1H, m, 3-H), 1.95 (2H, t,
t
JZ3.5 Hz, 4-H), 2.35 (1H, dd, JZ5.3, 15.2 Hz, –CHaCO2–
), 2.56 (1H, dd, JZ8.5, 15.2 Hz, –CHbCO2–), 3.57 (1H, m,
5-H), 3.65 (1H, dq, JZ2.2, 6.4 Hz, 6-H), 3.69 (3H, s,
–OMe), 3.99 (1H, ddd, JZ2.9, 5.3, 8.5 Hz, 2-H), 4.72 (1H,
d, JZ9.2 Hz, –NH–); 13C NMR (75.5 MHz, CDCl3): d
(ppm) 15.2, 17.6, 28.4, 29.1, 35.8, 38.4, 48.0, 51.7, 76.5,
77.3, 79.0, 155.8, 171.8. Anal. Calcd for C15H27NO5: C,
59.78; H, 9.03; N, 4.65. Found: C, 59.91; H, 9.06; N, 4.64.
Methyl (E)-(3R,5R,6R)-(5-t-butoxycarbonylamino-3,6-
dimethyltetrahydropyran-2-ylidene)acetate (13E, more
polar). n2D6Z1.4888; [a]D26 K19.4 (c 0.60, CHCl3); IR
(film): nmax 3340, 2978, 1714, 1705, 1697, 1633, 1520,
1167 cmK1; 1H NMR (300 MHz, C6D6): d (ppm) 0.53 (3H,
d, JZ6.0 Hz, 3-CH3), 0.61 (1H, ddd, JZ5.1, 12.2, 13.4 Hz,
2.1.9. (2S,3S,5R,6R)-(5-t-Butoxycarbonylamino-3,6-
dimethyltetrahydropyran-2-yl)acetaldehyde (16). To a
cooled (K78 8C) solution of 15 (2.57 g, 8.53 mmol) in
toluene (25 mL) was added diisobutylaluminum hydride
(17.8 mL of 0.96 M in hexanes, 17.1 mmol) and the mixture
was stirred for 30 min at this temperature. The reaction was
quenched with MeOH (3.5 mL), poured into 1 N HCl
solution (300 mL) and extracted with EtOAc. The combined
organic layer was washed with saturated NaHCO3 solution
and brine, dried with MgSO4 and concentrated under
reduced pressure. Purification on silica gel (3:1 hexanes/
EtOAc) gave aldehyde 16 as a colorless oil (2.29 g, 98%);
n2D5Z1.4665; [a]D26 K27.2 (c 0.32, CHCl3); IR (film): nmax
t
4-Ha), 1.19 (3H, d, JZ6.2 Hz, 6-CH3), 1.39 (9H, s, Bu),
1.63 (1H, ddd, JZ2.6, 6.8, 13.4 Hz, 4-Hb), 1.73 (1H, m,
3-H), 3.51 (3H, s, –OMe), 3.70 (1H, dq, JZ3.5, 6.2 Hz,
6-H), 3.83 (1H, m, 5-H), 4.53 (1H, d, JZ9.3 Hz, –NH–),
4.92 (1H, d, JZ1.2 Hz, ]CHCO2–); 13C NMR (75.5 MHz,
C6D6): d (ppm) 15.7, 16.6, 28.4, 30.2, 36.0, 48.3, 50.2, 72.8,
78.9, 91.6, 155.6, 165.5, 172.4; HRMS (FAB) m/z Calcd for
C15H25NO5: 299.1733 (MC). Found: 299.1721.
2.1.7. Methyl (2R,3R)-(3-t-butoxycarbonylamino-2,5-
dimethyl-3,4-dihydro-2H-pyran-6-yl)acetate (14). To a
solution of 13 (mixture of 13Z and 13E, 38.3 mg,
0.128 mmol) in benzene (2 mL) was added DBU (191 mL,
1.28 mmol) and the mixture was stirred for 6 h at 100 8C
(bath temperature). The solvent was removed under reduced
pressure. The residue was purified by column chromato-
graphy on silica gel (5:1 hexanes/EtOAc) to provide 14 as a
colorless oil (38.3 mg, 100%); n2D5Z1.4700; [a]D24 C29.2 (c
0.22, CHCl3); IR (film): nmax 3410, 2979, 1745, 1714, 1695,
3460, 2976, 1722, 1714, 1496, 1171 cmK1 1H NMR
;
(300 MHz, CDCl3): d (ppm) 1.03 (3H, d, JZ7.2 Hz, 3-CH3),
1.11 (3H, d, JZ6.3 Hz, 6-CH3), 1.42 (9H, s, tBu), 1.78 (1H,
m, 3-H), 1.95 (2H, m, 4-H), 2.34 (1H, ddd, JZ2.2, 4.1,
16.4 Hz, –CHaCHO), 2.64 (1H, ddd, JZ2.2, 9.3, 16.4 Hz,
–CHbCHO), 3.57 (1H, m, 5-H), 3.66 (1H, dq, JZ2.3,
6.3 Hz, 6-H), 4.06 (1H, ddd, JZ3.1, 4.1, 9.3 Hz, 2-H), 4.69
(1H, d, JZ9.1 Hz, –NH–), 9.77 (1H, t, JZ2.2 Hz, –CHO);
13C NMR (75.5 MHz, CDCl3): d (ppm) 15.3, 17.5, 28.4,
29.3, 35.7, 46.9, 47.9, 75.8, 76.4, 79.1, 155.7, 201.1. Anal.
Calcd for C14H25NO4: C, 61.97; H, 9.29; N, 5.16. Found:
C, 61.72; H, 9.30; N, 5.24.
1505, 1366, 1162 cmK1 1H NMR (300 MHz, C6D6): d
;
(ppm) 1.14 (3H, d, JZ6.3 Hz, 2-CH3), 1.27 (3H, s, 5-CH3),
1.45 (9H, s, tBu), 1.71 (1H, d, JZ17.1 Hz, 4-Ha), 2.03 (1H,
dd, JZ4.7, 17.1 Hz, 4-Hb), 2.88, 2.97 (2H, two d, JZ
16.7 Hz, –CH2CO2–), 3.30 (3H, s, –OMe), 3.61 (1H, q, JZ
6.3 Hz, 2-H), 3.95 (1H, ddt, JZ4.7, 9.6, 1.6 Hz, 3-H), 5.21
(1H, d, JZ9.6 Hz, –NH–); 13C NMR (75.5 MHz, C6D6): d
(ppm) 17.4, 17.5, 28.4, 35.1, 36.2, 47.2, 51.4, 73.0, 78.6,
103.2, 142.1, 156.1, 170.4. Anal. Calcd for C15H25NO5: C,
60.18; H, 8.42; N, 4.68. Found: C, 60.17; H, 8.38; N, 4.68.
2.1.10. Ethyl (2E,20S,30S,50R,60R)-4-(50-t-butoxycarbonyl-
amino-30,60-dimethyltetrahydropyran-20-yl)-2-methyl-
but-2-enoate (17). To a solution of aldehyde 16 (66.1 mg,
0.24 mmol) in benzene (1 mL) was added (carbethoxyethy-
lidene)triphenylphosphorane (113 mg, 0.29 mmol) and the
mixture was stirred for 3 h at 60 8C. The solvent was
removed under reduced pressure. The residue was purified
by silica gel column chromatography (4:1 hexanes/EtOAc)
to furnish desired 17 (80.6 mg, 93%) and undesired
Z-derivative (3.5 mg, 4%); n2D2Z1.4755; [a]D26 K13.2
(c 0.56, CHCl3); IR (film): nmax 3462, 3384, 2978, 1722,
2.1.8. Methyl (2S,3S,5R,6R)-(5-t-butoxycarbonylamino-
3,6-dimethyltetrahydropyran-2-yl)acetate (15). To a
solution of 14 (5.52 g, 18.4 mmol) in acetic acid (40 mL)
was added PtO2 (550 mg) and the mixture was stirred for
36 h under H2 atmosphere (5 atm) using a Parr’s hydro-
genator. The mixture was filtered through Celitew and
neutralized by addition of saturated NaHCO3 solution and
then extracted with EtOAc. The combined organic layer
was washed with water and brine before drying
with MgSO4. The solvent was removed and the residue
was purified by column chromatography on silica gel
(5:1–1:1 hexanes/EtOAc) to give a mixture of compound 15
1714, 1651, 1504, 1171 cmK1
;
1H NMR0 (300 MHz,
CDCl3): d (ppm) 1.04 (3H, d, JZ7.2 Hz, 3 -CH3), 1.15
(3H, d, JZ6.3 Hz, 60-CH3), 1.30 (3H, t, JZ7.0 Hz, CH3 of
t
–OEt), 1.44 (9H, s, Bu), 1.77 (1H, m, 30-H), 1.85 (3H, d,
JZ1.4 Hz, 2-CH3), 1.90–1.95 (2H, m, 40-H), 2.25 (1H, m,
4-Ha), 2.40 (1H, m, 4-Hb), 3.5–3.7 (3H, m, 20-H, 50-H, 60-H),
4.19 (2H, q, JZ7.0 Hz, CH2 of –OEt), 4.73 (1H, d,
JZ8.7 Hz, –NH–), 6.73 (1H, ddq, JZ6.5, 7.8, 1.4 Hz,

1384
H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
3-H); 13C NMR (75.5 MHz, CDCl3): d (ppm) 12.6, 14.2,
15.0, 17.6, 28.4, 29.1, 32.4, 35.9, 48.2, 60.5, 76.4, 79.0,
79.8, 129.4, 137.8, 155.8, 167.9. Anal. Calcd for
C19H33NO5: C, 64.20; H, 9.36; N, 3.94. Found: C, 64.36;
H, 9.38; N, 3.82.
126.0, 131.0, 135.2, 153.0, 155.7, 166.3; HRMS (FAB) m/z
Calcd for C24H35N2O3S2: 463.2089 (MCCH). Found:
463.2083.
2.1.13. (20E,200S,300S,500R,600R)-2-{[40-(500-t-Butoxy-
carbonylamino-300,600-dimethyltetrahydropyran-200-yl)-
20-methylbut-20-en-10-yl]sulfonyl}-1,3-benzothiazole (20).
To a solution of sulfide 19 (20.6 mg, 0.045 mmol) in EtOH
(0.3 mL) were added (NH4)6Mo7O24$4H2O (11 mg,
0.0089 mmol) and H2O2 (34%, 45 mL, 0.445 mmol) at
0 8C. The mixture was stirred at room temperature for 2 h,
and then treated with 10% sodium thiosulfate solution. The
aqueous layer was extracted with EtOAc, and the resulting
organic layer was washed with saturated NaHCO3 solution
and brine before drying with MgSO4. The solvent was
removed and the residue was purified by column chromato-
graphy on silica gel (2:1 hexanes/EtOAc) to yield sulfone 20
as a colorless viscous oil (19.2 mg, 87%); n2D5Z1.5170;
[a]2D9 K20.3 (c 0.38, CHCl3); IR (film): nmax 3460, 2976,
2.1.11. (2E,20S,30S,50R,60R)-4-(50-t-Butoxycarbonyl-
amino-30,60-dimethyltetrahydropyran-20-yl)-2-methyl-
but-2-en-1-ol (18). A stirred solution of 17 (2.92 g,
8.21 mmol) in toluene (33 mL) was cooled to K68 8C,
treated with diisobutylaluminum hydride (25.7 mL of
0.96 M in hexanes, 24.6 mmol) and warmed to 0 8C during
15 min. The reaction mixture was again cooled to K68 8C
and quenched with MeOH (5 mL). The resultant mixture
was poured into 1 N HCl solution (300 mL) and extracted
with EtOAc. The combined organic layer was washed with
water, saturated NaHCO3 solution and brine, dried with
MgSO4 and concentrated under reduced pressure. The
residue was purified by silica gel column chromatography
(1:1 hexanes/EtOAc) to give alcohol 18 as a colorless oil
(2.56 g, 99%); nD24Z1.4823; [a]D25 K4.0 (c 0.75, CHCl3); IR
(film): nmax 3458, 2976, 1714, 1504, 1169 cmK1; 1H NMR
(300 MHz, CDCl3): d (ppm) 1.00 (3H, d, JZ7.2 Hz,
30-CH3), 1.12 (3H, d, JZ6.4 Hz, 60-CH3), 1.41 (9H, s,
tBu), 1.65 (3H, s, 2-CH3), 1.73 (1H, m, 30-H), 1.85–1.90
(2H, m, 40-H), 1.92 (1H, s, –OH), 2.11 (1H, m, 4-Ha), 2.26
(1H, m, 4-Hb), 3.46 (1H, dt, JZ2.7, 7.2 Hz, 20-H), 3.52 (1H,
m, 50-H), 3.58 (1H, dq, JZ2.2, 6.4 Hz, 60-H), 3.98 (2H, s,
1-H), 4.75 (1H, d, JZ9.3 Hz, –NH–), 5.38 (1H, ddq, JZ6.3,
7.6, 1.3 Hz, 3-H); 13C NMR (75.5 MHz, CDCl3): d (ppm)
13.9, 14.9, 17.7, 28.3, 28.8, 31.2, 35.9, 48.3, 68.5, 76.2,
79.0, 80.7, 121.2, 136.6, 155.8. Anal. Calcd for C17H31NO4:
C, 65.14; H, 9.97; N, 4.47. Found: C, 65.36; H, 10.12;
N, 4.46.
1714, 1496, 1331 cmK1 1H NMR (300 MHz, CDCl3):
;
d (ppm) 0.76 (3H, d, JZ7.2 Hz, 300-CH3), 0.96 (3H, d,
t
JZ6.3 Hz, 600-CH3), 1.16 (1H, m, 300-H), 1.38 (9H, s, Bu),
1.50 (1H, m, 400-Ha), 1.64 (1H, m, 400-Hb), 1.84 (3H, s,
20-CH3), 1.98 (1H, m, 40-Ha), 2.12 (1H, m, 40-Hb), 3.02 (1H,
dt, JZ2.5, 7.1 Hz, 200-H), 3.19 (1H, dq, JZ1.9, 6.3 Hz,
600-H), 3.39 (1H, m, 500-H), 4.12, 4.19 (2H, two d,
JZ13.8 Hz, 10-H), 0 4.56 (1H, d, JZ9.3 Hz, –NH–), 5.27
(1H, t, JZ6.8 Hz, 3 -H), 7.5–7.65 (2H, m, Har), 7.97 (1H, br
d, JZ8.2 Hz, Har), 8.19 (1H, br d, JZ8.2 Hz, Har);
13C NMR (75.5 MHz, CDCl3): d (ppm) 14.7, 17.0, 17.5,
28.4, 28.6, 32.0, 35.7, 48.0, 64.3, 76.2, 79.0, 79.9, 122.2,
123.8, 125.4, 127.7, 128.0, 133.4, 136.8, 152.7, 155.7,
165.6; HRMS (FAB) m/z Calcd for C24H35N2O5S2:
495.1987 (MCCH). Found: 495.1979.
2.1.14. (20E,200S,300S,500R,600R)-2-{[40-(500-Amino-300,600-
dimethyltetrahydropyran-200-yl)-20-methylbut-20-en-10-yl]
sulfonyl}-1,3-benzothiazole (21). A solution of 20 (82 mg,
0.166 mmol) in 4 N HCl/EtOAc (2 mL) was stirred for
90 min at room temperature. The reaction mixture was
neutralized with saturated NaHCO3 solution and extracted
with CHCl3 (four times). The organic layer was dried with
Na2SO4 and evaporated to provide amine 21 (65 mg) as a
colorless oil. This crude product was used in the next
2.1.12. (20E,200S,300S,500R,600R)-2-{[40-(500-t-Butoxy-
carbonylamino-300,600-dimethyltetrahydropyran-200-yl)-
20-methylbut-20-en-10-yl]sulfanyl}-1,3-benzothiazole (19).
To a cooled (0 8C) solution of 2-mercaptobenzothiazole
(16 mg, 0.096 mmol) and triphenylphosphine (25 mg,
0.096 mmol) in THF (0.2 mL) was added a solution of the
allylic alcohol 18 (20.0 mg, 0.064 mmol) in THF (0.2 mL)
over 10 min. To the resulting solution was added
diisopropyl azodicarboxylate (40% in toluene, 52 mL,
0.096 mmol) over 10 min. After stirring was continued at
0 8C for 3 h, the mixture was evaporated to dryness. The
residue was dissolved in hexane and filtered through Celitew
pad. Further purification of the resulting solution by silica
gel column chromatography (10:1–3:1 hexanes/EtOAc)
afforded sulfide 19 as a colorless viscous oil (28.4 mg,
96%); n2D5Z1.5166; [a]D30 K7.1 (c 0.51, CHCl3); IR (film):
nmax 2976, 1714, 1504 cmK1; 1H NMR (300 MHz, CDCl3):
d (ppm) 0.87 (3H, d, JZ7.2 Hz, 300-CH3), 1.06 (3H, d,
JZ6.3 Hz, 600-CH3), 1.40 (9H, s, tBu), 1.45 (1H, m, 300-H),
1.6–1.8 (2H, m, 400-H), 1.75 (3H, s, 20-CH3), 2.05 (1H, m,
40-Ha), 2.21 (1H, m, 40-Hb), 3.32 (1H, dt, JZ2.6, 7.4 Hz,
200-H), 3.4–3.50 (2H, m, 500-H, 600-H), 3.90, 3.96 (2H, two d,
JZ13.1 Hz, 1 -H), 4.66 (1H, d, JZ9.3 Hz, –NH–), 5.49
(1H, t, JZ6.6 Hz, 30-H), 7.24 (1H, br t, JZ7.8 Hz, Har),
7.36 (1H, br t, JZ7.8 Hz, Har), 7.69 (1H, br d, JZ7.8 Hz,
Har), 7.82 (1H, br d, JZ7.8 Hz, Har); 13C NMR (75.5 MHz,
CDCl3): d (ppm) 14.7, 15.4, 17.5, 28.3, 28.6, 31.7, 35.7,
43.0, 48.1, 76.1, 78.8, 80.3, 120.7, 121.4, 124.2, 125.9,
1
reaction without further purification; H NMR (300 MHz,
CDCl3): d (ppm) 0.84 (3H, d, JZ7.5 Hz, 300-CH3), 1.03 (3H,
d, JZ6.4 Hz, 600-CH3), 1.14 (1H, m, 300-H), 1.5–1.65 (4H,
m, H-400, –NH2), 1.86 (3H, s, 20-CH3), 2.04 (1H, m, 40-Ha),
2.17 (1H, m, 40-Hb), 2.53 (1H, m, 500-H), 3.07 (1H, dt,
JZ2.8, 7.3 Hz, 200-H), 3.21 (1H, dq, JZ2.0, 6.4 Hz, 600-H),
4.15, 4.21 (2H, two d, JZ13.2 Hz, 10-H), 5.31 (1H, t,
JZ6.6 Hz, 30-H), 7.55–7.67 (2H, m, Har), 8.00 (1H, br d,
JZ7.4 Hz, Har), 8.22 (1H, br d, JZ7.4 Hz, Har).
2.1.15. (2Z,4S)-4-(t-Butyldimethylsilyloxy)pent-2-enoic
acid (23). To a solution of methyl ester 22 (500 mg,
2.05 mmol) in MeOH–H2O (20:1, 10 mL) was added
LiOH$H2O (430 mg) and the mixture was stirred overnight
at room temperature. The reaction mixture was neutralized
with 3 N HCl and extracted with EtOAc. The organic layer
was washed with brine, dried with MgSO4 and evaporated.
Purification of the residue on silica gel (4:1 hexanes/EtOAc)
provided carboxylic acid 23 as a colorless oil (431 mg,

H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
1385
91%); n2D5Z1.4465; [a]D28 C57.7 (c 0.86, CHCl3); IR (film):
2.1.18. (1S,3R,6R,9S)-8-Methoxy-3-(40-methoxyphenyl)-
8-methyl-10-methylene-2,4,7-trioxabicyclo[4.4.0]decane
(27). To a cooled (K20 8C) solution of ketone 26 (102 mg,
0.329 mmol) and pyridine (2.7 mL, 0.033 mmol) in THF
(2 mL) was added Tebbe reagent (0.99 mL of 0.5 M in
toluene, 0.494 mmol) under argon and stirred for 20 min.
The reaction was quenched with 2 N NaOH solution
(0.49 mL, 0.98 mmol) at this temperature. After gas
evolution ceased, Celitew was added to the resultant
solution and stirring was continued for a few hours at
room temperature. This reaction mixture was filtered
through Celitew, and then the solvent was removed under
reduced pressure. Purification of the residue on silica gel
(9:1 hexanes/EtOAc) provided 27 as colorless crystals
(95 mg, 94%); mp 98–100 8C; [a]1D9 C112 (c 1.46, CHCl3);
1
nmax 2956, 1695, 1645, 1254 cmK1; H NMR (300 MHz,
CDCl3): d (ppm) 0.05, 0.07 (6H, two s, –SiMe), 0.89 (9H, s,
tBu), 1.27 (3H, d, JZ6.6 Hz, 5-H), 5.40 (1H, m, 4-H), 5.69
(1H, dd, JZ1.2, 11.8 Hz, 2-H), 6.35 (1H, dd, JZ7.7,
11.8 Hz, 3-H); 13C NMR (75.5 MHz, CDCl3): d (ppm)
K4.8, K4.8, 18.1, 23.4, 25.8, 65.6, 116.4, 157.2, 171.4.
Anal. Calcd for C11H22O3Si: C, 57.35; H, 9.63. Found: C,
57.23; H, 9.58.
2.1.16. (1S,2R,4S,6R,9R)-4-Methoxy-9-(40-methoxy-
phenyl)-4-methyl-5,8,10-trioxabicyclo[4.4.0]decan-2-ol
(25). To a solution of triol 24 (523 mg, 2.72 mmol) in DMF
(10 mL) were added p-toluenesulfonic acid (5.2 mg,
0.027 mmol) and 4-methoxybenzaldehyde dimethyl acetal
(927 mL, 5.44 mmol) at room temperature. The mixture was
stirred at 60 8C under slightly reduced pressure (water
aspirator) for 40 min and then poured into water. The
aqueous layer was extracted with EtOAc, and the resulting
organic layer was washed with water, saturated NaHCO3
solution and brine before drying with MgSO4. The solvent
was removed and the residue was purified by column
chromatography on silica gel (3:1–1:1 hexanes/EtOAc) to
yield alcohol 25 as a colorless amorphous solid (710 mg,
84%); [a]2D3 C72.2 (c 0.91, CHCl3); IR (film): nmax 3496,
IR (KBr): nmax 1614, 1520, 1385, 1248, 1088, 1045 cmK1
;
1H NMR (300 MHz, CDCl3): d (ppm) 1.38 (3H, s, 8-CH3),
2.46 (1H, d, JZ14.1 Hz, 9-Ha), 2.59 (1H, d, JZ14.1 Hz,
9-Hb), 3.23 (3H, s, –OMe of acetal), 3.66 (1H, dt, JZ4.4,
9.8 Hz, 6-H), 3.78 (1H, t, JZ9.8 Hz, 5-Ha), 3.81 (3H, s,
–OMe of PMP), 3.99 (1H, d, JZ9.8 Hz, 1-H), 4.23 (1H, dd,
JZ4.4, 9.8 Hz, 5-Hb), 4.91 (1H, d, JZ1.5 Hz, methylene
Ha), 5.14 (1H, d, JZ1.5 Hz, methylene Hb), 5.60 (1H, s,
3-H), 6.90 (2H, d, JZ8.7 Hz, Har), 7.46 (2H, d, JZ8.7 Hz,
Har); 13C NMR (75.5 MHz, CDCl3): d (ppm) 22.7, 44.8,
48.2, 55.2, 55.2, 66.7, 69.5, 79.5, 99.8, 101.4, 101.5, 107.1,
113.5, 127.5, 130.2, 139.3, 160.0; HRMS (FAB) m/z Calcd
for C17H23O5: 307.1546 (MCCH). Found: 307.1547.
1616, 1518, 1250 cmK1 1H NMR (300 MHz, CDCl3):
;
d (ppm) 1.34 (3H, s, 4-CH3), 1.61 (1H, dd, JZ11.4, 13.1 Hz,
3-Ha), 2.23 (1H, dd, JZ5.1, 13.1 Hz, 3-Hb), 2.71 (1H, br s,
–OH), 3.20 (3H, s, –OMe of acetal), 3.38 (1H, t, JZ9.5 Hz,
1-H), 3.63 (1H, dt, JZ4.4, 9.5 Hz, 6-H), 3.72 (1H, t,
JZ9.5 Hz, 7-Ha), 3.79 (3H, s, –OMe of PMP), 4.12 (1H, m,
2-H), 4.23 (1H, dd, JZ4.4, 9.5 Hz, 7-Hb), 5.50 (1H, s, 9-H),
6.89 (2H, d, JZ8.4 Hz, Har), 7.42 (2H, d, JZ8.4 Hz, Har);
13C NMR (75.5 MHz, CDCl3): d (ppm) 22.7, 42.9, 47.8,
55.2, 55.2, 63.6, 66.2, 69.0, 83.7, 100.1, 101.8, 101.9, 113.6,
127.5, 129.8, 160.1; HRMS (FAB) m/z Calcd for C16H23O6:
311.1495 (MCCH). Found: 311.1501.
2.1.19. (2R,3S,6S)-[6-Methoxy-3-(40-methoxybenzyloxy)-
6-methyl-4-methylenetetrahydropyran-2-yl]methanol
(28). To a cooled (K15 8C) solution of 27 (290 mg,
0.947 mmol) in dichloromethane (5 mL) was added diiso-
butylaluminum hydride (4.5 mL of 0.95 M in hexanes,
4.26 mmol) under argon and the mixture was stirred for 3 h
at this temperature. The reaction was quenched with MeOH
(0.35 mL, 8.52 mmol) and then treated with saturated
aqueous potassium sodium tartrate solution. The resultant
solution was extracted with EtOAc. The combined organic
layer was washed with saturated NaHCO3 solution and brine
and then dried with MgSO4. The solvent was removed under
reduced pressure and the residue was purified by silica gel
column chromatography (3:1 hexanes/EtOAc) to give 28 as
a colorless oil (265 mg, 91%); n2D1Z1.5166; [a]D21 C185
(c 0.78, CHCl3); IR (film): nmax 3477, 1612, 1514,
2.1.17. (1R,4S,6R,9R)-4-Methoxy-9-(40-methoxyphenyl)-
4-methyl-5,8,10-trioxabicyclo[4.4.0]decan-2-one (26). To
a solution of alcohol 25 (1.63 g, 5.25 mmol) and pyridine
(5.10 mL, 63.0 mmol) in dichloromethane (52 mL) was
added Dess–Martin periodinane (6.68 g, 15.8 mmol) and
stirred for 18 h at room temperature. The reaction mixture
was diluted with ether, washed twice with a 1:1 mixture of
saturated NaHCO3 solution and 10% sodium thiosulfate
solution and then washed with brine. The combined organic
layer was dried with MgSO4 and concentrated. After
column chromatography on silica gel (1:1 hexanes/
EtOAc), ketone 26 was isolated as colorless crystals
(1.54 g, 95%); mp 113–115 8C; [a]2D3 C119 (c 0.93,
1
1250 cmK1; H NMR (300 MHz, CDCl3): d (ppm) 1.35
(3H, s, 6-CH3), 1.94 (1H, t, JZ6.3 Hz, –OH), 2.34 (1H, d,
JZ13.5 Hz, 5-Ha), 2.55 (1H, d, JZ13.5 Hz, 5-Hb), 3.18
(3H, s, –OMe of acetal), 3.50 (1H, dt, JZ9.5, 3.7 Hz, 2-H),
3.67–3.86 (3H, m, 3-H and –CH2OH), 3.80 (3H, s, –OMe of
PMB), 4.46, 4.69 (2H, two d, JZ11.1 Hz, CH2 of PMB),
4.94 (1H, s, methylene Ha), 5.19 (1H, s, methylene Hb), 6.89
(2H, d, JZ8.7 Hz, Har), 7.29 (2H, d, JZ8.7 Hz, Har);
13C NMR (75.5 MHz, CDCl3): d (ppm) 22.7, 45.0, 48.2,
55.2, 62.7, 72.6, 74.1, 76.0, 99.2, 108.3, 113.8, 129.6, 130.0,
141.3, 159.3; HRMS (FAB) m/z Calcd for C17H25O5:
309.1702 (MCCH). Found: 309.1702.
1
CHCl3); IR (KBr): nmax 3450, 1734, 1248, 1099 cmK1; H
NMR (300 MHz, CDCl3): d (ppm) 1.45 (3H, s, 4-CH3), 2.64
(1H, d, JZ14.3 Hz, 3-Ha), 2.70 (1H, d, JZ14.3 Hz, 3-Hb),
3.21 (3H, s, –OMe of acetal), 3.78 (3H, s, –OMe of PMP),
3.87 (1H, t, JZ9.6 Hz, 7-Ha), 3.96 (1H, dt, JZ4.0, 9.6 Hz,
6-H), 4.24 (1H, d, JZ9.6 Hz, 1-H), 4.33 (1H, dd, JZ4.0,
9.6 Hz, 7-Hb), 5.51 (1H, s, 9-H), 6.86 (2H, d, JZ8.6 Hz,
Har), 7.42 (2H, d, JZ8.6 Hz, Har); 13C NMR (75.5 MHz,
CDCl3): d (ppm) 22.5, 48.2, 51.7, 55.2, 55.2, 66.0, 69.4,
82.6, 101.9, 102.0, 103.0, 113.5, 127.7, 129.1, 160.2, 198.2;
HRMS (FAB) m/z Calcd for C16H21O6: 309.1338 (MCC
H). Found: 309.1339.
2.1.20. (2R,3S,6S)-[6-Methoxy-3-(40-methoxybenzyloxy)-
6-methyl-4-methylenetetrahydropyran-2-yl]methyl
pivalate (29). To a cooled (0 8C) solution of alcohol 28
(42 mg, 0.136 mmol), triethylamine (57 mL, 0.409 mmol)
and DMAP (1.7 mg, 0.014 mmol) in dichloromethane

1386
H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
(0.5 mL) was added PivCl (22 mL, 0.177 mmol) and this
mixture was stirred for 12 h at room temperature. The
reaction mixture was poured into water and extracted with
EtOAc. The organic layer was washed with saturated
NaHCO3 solution and brine, dried with MgSO4 and then
evaporated. Purification of the residue on silica gel (10:1
hexanes/EtOAc) furnished 29 as a colorless oil (51 mg, 95%);
n2D0Z1.4926; [a]D25 C150 (c 0.99, CHCl3); IR (film): nmax
2962, 1732, 1612, 1514 cmK1; 1H NMR (300 MHz, CDCl3):
d (ppm) 1.20 (9H, s, tBu), 1.33 (3H, s, 6-CH3), 2.34 (1H, d,
JZ13.7 Hz, 5-Ha), 2.55 (1H, d, JZ13.7 Hz, 5-Hb), 3.20 (3H,
s, –OMe of acetal), 3.68 (1H, ddd, JZ1.9, 5.9, 9.7 Hz, 2-H),
3.76 (1H, d, JZ9.7 Hz, 3-H), 3.80 (3H, s, –OMe of PMB),
4.14 (1H, dd, JZ5.9, 11.6 Hz, Ha of PivOCH2–), 4.39 (1H,
dd, JZ1.9, 11.6 Hz, Hb of PivOCH2–), 4.40, 4.66 (2H, two d,
JZ10.7 Hz, CH2 of PMB), 4.95 (1H, d, JZ1.4 Hz,
methylene Ha), 5.18 (1H, d, JZ1.4 Hz, methylene Hb), 6.88
(2H, d, JZ8.6 Hz, Har), 7.28 (2H, d, JZ8.6 Hz, Har); 13C
NMR (75.5 MHz, CDCl3): d (ppm) 22.6, 27.2, 38.8, 44.8,
48.0, 55.1, 63.7, 72.4, 72.5, 76.2, 99.0, 108.8, 113.8, 129.5,
129.8, 140.9, 159.3, 178.1; HRMS (FAB) m/z Calcd for
C22H33O6: 393.2277 (MCCH). Found: 393.2277.
chromatography (1:1 hexanes/EtOAc) to furnish 31 as
colorless crystals (135 mg, 84%); mp 77–78 8C; [a]1D9 C115
(c 0.88, CHCl3); IR (KBr): nmax 3423, 2987, 1729 cmK1; 1H
t
NMR (300 MHz, CDCl3): d (ppm) 1.23 (9H, s, Bu), 1.36
(3H, s, 7-CH3), 1.73 (1H, d, JZ14.7 Hz, 8-Ha), 1.88 (1H, d,
JZ10.3 Hz, –OH), 2.27 (1H, d, JZ14.7 Hz, 8-Hb), 2.50
(1H, d, JZ4.5 Hz, 2-Ha), 2.99 (1H, d, JZ4.5 Hz, 2-Hb),
3.27 (3H, s, –OMe), 3.67 (1H, t, JZ10.3 Hz, 4-H), 3.79
(1H, ddd, JZ2.2, 6.2, 10.3 Hz, 5-H), 4.23 (1H, dd, JZ6.2,
11.8 Hz, Ha of PivOCH2–), 4.48 (1H, dd, JZ2.2, 11.8 Hz,
Hb of PivOCH2–); 13C NMR (75.5 MHz, CDCl3): d (ppm)
22.7, 27.2, 38.8, 41.8, 47.0, 48.1, 56.2, 64.0, 64.1, 70.8,
98.4, 178.4. Anal. Calcd for C14H24O6: C, 58.32; H, 8.39.
Found: C, 58.20; H, 8.37.
2.1.23. (3R,4R,5R,7S)-(4-t-Butyldimethylsilyloxy-7-
methoxy-7-methyl-1,6-dioxaspiro[2.5]oct-5-yl)methyl
pivalate (32). To a solution of epoxyalcohol 31 (58 mg,
0.20 mmol) in DMF (0.1 mL) was added TBSCN (510 mg
in all, 3.61 mmol) in 3 equal portions at intervals of 20 h.
Stirring was continued for 2 days at 70 8C. The reaction
mixture was diluted with EtOAc, washed with saturated
NaHCO3 solution and brine, and then dried with MgSO4.
The solvent was removed under reduced pressure and the
residue was purified by silica gel column chromatography
(6:1–1:2 hexanes/EtOAc) to give 32 as a colorless oil
(56 mg, 70%) and unreacted starting material (13 mg). The
yield was calculated to be 91% based on the recovered
starting material; nD20Z1.4586; [a]D17 C123 (c 1.07, CHCl3);
IR (film): nmax 2958, 1732, 1479, 1284, 1257 cmK1; 1H NMR
(300 MHz, CDCl3): d (ppm) 0.07, 0.10 (6H, two s, –SiMe),
0.90 (9H, s, –SiBut), 1.22 (9H, s, –COBut), 1.33 (3H, s,
7-CH3), 1.72 (1H, d, JZ14.1 Hz, 8-Ha), 2.16 (1H, d,
JZ14.1 Hz, 8-Hb), 2.43 (1H, d, JZ5.1 Hz, 2-Ha), 2.87
(1H, d, JZ5.1 Hz, 2-Hb), 3.28 (3H, s, –OMe), 3.78 (1H, d,
JZ9.3 Hz, 4-H), 3.97 (1H, dd, JZ7.4, 11.1 Hz, Ha of
PivOCH2–), 4.05 (1H, m, 5-H), 4.48 (1H, dd, JZ1.4,
11.1 Hz, Hb of PivOCH2–); 13C NMR (75.5 MHz, CDCl3):
d (ppm) K4.5, K4.5, 18.1, 22.9, 25.7, 27.2, 38.8, 42.7, 47.3,
48.0, 57.1, 63.7, 66.5, 70.5, 98.7, 178.2; HRMS (FAB) m/z
Calcd for C20H39O6Si: 403.2516 (MCCH). Found:
403.2523.
2.1.21. (2R,3S,6S)-(3-Hydroxy-6-methoxy-6-methyl-4-
methylenetetrahydropyran-2-yl)methyl pivalate (30).
To a cooled (0 8C) solution of 29 (51 mg, 0.13 mmol) in
dichloromethane (1 mL) were added NaHCO3 (66 mg,
0.79 mmol), DDQ (90 mg, 0.40 mmol) and water (30 mL),
respectively, in 3 portions at intervals of 3 h. Stirring was
kept for 8 h at this temperature. The reaction mixture was
poured into 10% sodium thiosulfate solution and extracted
with EtOAc. The organic layer was washed with a 1:1
mixture of saturated NaHCO3 solution and 10% sodium
thiosulfate solution and with brine, and then dried with
MgSO4. After removal of the solvent, purification of the
residue on silica gel (6:1–2:1 hexanes/EtOAc) provided
alcohol 30 as a colorless oil (33 mg, 92%); n1D9Z1.4645;
[a]1D5 C108 (c 1.02, CHCl3); IR (film): nmax 3474, 2959,
1
1731, 1481, 1287 cmK1; H NMR (300 MHz, CDCl3): d
t
(ppm) 1.24 (9H, s, Bu), 1.36 (3H, s, 6-CH3), 2.35 (1H, d,
JZ14.0 Hz, 5-Ha), 2.50 (1H, d, JZ6.3 Hz, –OH), 2.55 (1H,
d, JZ14.0 Hz, 5-Hb), 3.21 (3H, s, –OMe), 3.51 (1H, ddd,
JZ2.3, 4.8, 9.8 Hz, 2-H), 3.85 (1H, br, 3-H), 4.31 (1H, dd,
JZ2.3, 12.1 Hz, Ha of PivOCH2–), 4.47 (1H, dd, JZ4.8,
12.1 Hz, Hb of PivOCH2–), 4.93 (1H, d, JZ1.5 Hz,
methylene Ha), 5.17 (1H, d, JZ1.5 Hz, methylene Hb);
13C NMR (75.5 MHz, CDCl3): d (ppm) 22.6, 27.2, 38.9,
44.7, 48.2, 64.2, 68.7, 73.9, 99.0, 107.9, 143.1, 179.3;
HRMS (FAB) m/z Calcd for C14H25O5: 273.1702 (MCCH).
Found: 273.1700.
2.1.24. (3R,4R,5R,7S)-(4-t-Butyldimethylsilyloxy-7-
methoxy-7-methyl-1,6-dioxaspiro[2.5]oct-5-yl)methanol
(33). To a cooled (K40 8C) solution of 32 (15.4 mg,
0.038 mmol) in THF (0.3 mL) was added diisobutylalumi-
num hydride (121 mL of 0.95 M in hexanes, 0.115 mmol)
under argon and the mixture was stirred for 2 h at this
temperature. The reaction was quenched with MeOH
(15 mL, 0.383 mmol) and then treated with saturated
aqueous potassium sodium tartrate solution. The resultant
solution was extracted with EtOAc. The combined organic
layer was washed with saturated NaHCO3 solution and brine
and then dried with MgSO4. The solvent was removed under
reduced pressure and the residue was purified by silica
gel column chromatography (5:1 hexanes/acetone) to
yield alcohol 33 as colorless crystals (11.1 mg, 91%); mp
51–52 8C; [a]D22 C138 (c 0.93, CHCl3); IR (KBr): nmax
2.1.22. (3R,4R,5R,7S)-(4-Hydroxy-7-methoxy-7-methyl-
1,6-dioxaspiro[2.5]oct-5-yl)methyl pivalate (31). To a
cooled (K15 8C) solution of allylic alcohol 30 (152 mg,
0.56 mmol) and NaHCO3 (188 mg, 2.23 mmol) in dichloro-
methane (3 mL) was added mCPBA (275 mg of O70%
purity, 1.12 mmol). The reaction mixture was gradually
warmed up to 0 8C during 3 h with stirring. The resultant
solution was diluted with EtOAc, washed successively with
a 1:1 mixture of 3 N NaOH solution and 10% sodium
thiosulfate solution and with brine, and then dried with
MgSO4. The solvent was removed under reduced pressure
and the residue was purified by silica gel column
1
3490, 2932, 1473, 1382, 1255 cmK1; H NMR (300 MHz,
CDCl3): d (ppm) 0.05, 0.11 (6H, two s, –SiMe), 0.88 (9H, s,
tBu), 1.34 (3H, s, 7-CH3), 1.70 (1H, d, JZ14.1 Hz, 8-Ha),
1.92 (1H, dd, JZ5.4, 7.5 Hz, –OH), 2.16 (1H, d,

H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
1387
JZ14.1 Hz, 8-Hb), 2.40 (1H, d, JZ5.0 Hz, 2-Ha), 2.86 (1H,
d, JZ5.0 Hz, 2-Hb), 3.24 (3H, s, –OMe), 3.69 (1H, m, Ha of
–CH2OH), 3.79 (1H, m, Hb of –CH2OH), 3.85 (2H, br s,
4-H, 5-H); 13C NMR (75.5 MHz, CDCl3): d (ppm) K4.7,
K4.5, 18.1, 23.0, 25.7, 42.7, 47.0, 48.1, 57.1, 61.8, 65.5,
72.1, 99.0; HRMS (FAB) m/z Calcd for C15H31O5Si:
319.1941 (MCCH). Found: 319.1940.
2.1.27. (2Z,20R,200E,30R,3000R,4S,400E,4000R,50S,5000R,60S,
7000S)-N-{60-[500-(4000-t-Butyldimethylsilyloxy-7000-methoxy-
7000-methyl-1000,6000-dioxaspiro[2.5]oct-5000-yl)-300-methylpenta-
200,400-dien-100-yl]-20,50-dimethyltetrahydropyran-30-yl}-
4-t-butyldimethylsilyloxypent-2-enamide (36). To a
cooled (K78 8C) solution of sulfone 35 (95 mg,
0.16 mmol) in THF (1.3 mL) was added LHMDS (330 mL
of 1.0 M in hexanes, 0.33 mmol) dropwise and the mixture
was stirred for 10 min. Then a solution of aldehyde 34
(40 mg, 0.13 mmol) in THF (0.4 mL) was added to the
resultant solution. Stirring was kept for 1 h at K78 8C and
for additional 2 h at room temperature. The reaction was
poured into saturated NH4Cl solution. The aqueous layer
was extracted with EtOAc, and the combined organic layer
was washed with saturated NaHCO3 solution and brine
before drying with MgSO4. The solvent was removed and
the residue was purified by column chromatography on
silica gel (7:1–2:1 hexanes/EtOAc) followed by preparative
HPLC (2.8:1 hexanes/EtOAc) to furnish diene 36 as a
colorless oil (61 mg, 68%); [a]2D1 C35.1 (c 1.04, CHCl3); IR
2.1.25. (3R,4R,5S,7S)-4-t-Butyldimethylsilyloxy-7-methoxy-
7-methyl-1,6-dioxaspiro[2.5]octane-5-carbaldehyde (34).
To a stirred solution of alcohol 33 (93 mg, 0.29 mmol) in
˚
dichloromethane (2 mL) were added powdered MS-4 A
(450 mg), NMO (44 mg, 0.38 mmol), and finally TPAP
(10 mg, 0.029 mmol) in this order. The reaction mixture
was stirred for 3 h at room temperature and then directly
purified by column chromatography on silica gel (2:1
hexanes/EtOAc) to provide aldehyde 34 as a colorless oil
(74 mg) containing a small amount of inseparable impurity.
The yield was calculated to be w80%. This product was
used in the next reaction without further purification;
1H NMR (300 MHz, CDCl3): d (ppm) 0.00, 0.03 (6H, two
s, –SiMe), 0.87 (9H, s, tBu), 1.40 (3H, s, 7-CH3), 1.75 (1H,
d, JZ14.3 Hz, 8-Ha), 2.18 (1H, d, JZ14.3 Hz, 8-Hb), 2.46
(1H, d, JZ5.1 Hz, 2-Ha), 2.88 (1H, d, JZ5.1 Hz, 2-Hb),
3.22 (3H, s, –OMe), 3.98 (1H, d, JZ9.6 Hz, 4-H), 4.40 (1H,
dd, JZ1.3, 9.6 Hz, 5-H), 9.74 (1H, d, JZ1.3 Hz, –CHO).
(CHCl3 solution): nmax 3441, 2929, 1666, 1501, 1255 cmK1
;
1H NMR (300 MHz, CDCl3): d (ppm) K0.05, 0.00, 0.03,
t
0.04 (12H, four s, –SiMe), 0.82, 0.86 (18H, two s, Bu),
0.97 (3H, d, JZ6.9 Hz, 50-CH3), 1.13 (3H, d, JZ6.6 Hz,
20-CH3), 1.25 (3H, d, JZ6.3 Hz, 5-H), 1.36 (3H, s,
7000-CH3), 1.70 (1H, d, JZ14.4 Hz, 8000-Ha), 1.7–1.82 (1H,
m, 50-H), 1.76 (3H, s, 300-CH3), 1.91 (2H, br s, 40-H),
2.2–2.45 (2H, m, 100-H), 2.22 (1H, d, JZ14.4 Hz, 8000-Hb),
2.40 (1H, d, JZ5.4 Hz, 2000-Ha), 2.87 (1H, d, JZ5.4 Hz,
2000-Hb), 3.23 (3H, s, –OMe), 3.52 (1H, dt, JZ2.4, 7.1 Hz,
60-H), 3.64 (1H, m, 20-H), 3.67 (1H, d, JZ8.9 Hz, 4000-H),
3.89 (1H, m, 30-0H0 ), 4.28 (1H, t, JZ8.9 Hz, 5000-H), 5.4300(1H,
t, JZ6.9 Hz, 2 -H), 5.48–5.61 (3H, m, 2-H, 4-H, 5 -H),
5.67 (1H, d, JZ9.0 Hz, –NH–), 5.99 (1H, dd, JZ7.7,
11.6 Hz, 3-H), 6.31 (1H, d, JZ15.6 Hz, 400-H); 13C NMR
(75.5 MHz, CDCl3): d (ppm) K4.8, K4.4, K4.1, 12.5,
15.1, 17.8, 18.0, 18.2, 23.1, 23.7, 25.6, 25.8, 28.8, 31.9,
35.8, 42.9, 47.0, 47.1, 48.2, 57.2, 65.3, 69.4, 73.8, 75.9,
80.8, 98.8, 119.1, 124.3, 128.7, 134.6, 138.5, 150.9, 165.1;
HRMS (FAB) m/z Calcd for C38H70NO7Si2: 708.4691
(MCCH). Found: 708.4694.
2.1.26. (2Z,20R,200E,30R,4S,50S,60S)-N-{60-[400-(1000,3000-
Benzothiazol-2000-ylsulfonyl)-300-methylbut-200-en-100-yl]-
20,50-dimethyltetrahydropyran-30-yl}-4-t-butyldimethyl-
silyloxypent-2-enamide (35). To a stirred solution of crude
amine 21 (65 mg) in acetonitrile (1 mL) were added
N-ethylmorpholine (23 mL, 0.182 mmol) and a solution of
carboxylic acid 23 (42 mg, 0.182 mmol) in acetonitrile
(1 mL). This mixture was cooled to 0 8C and HBTU (69 mg,
0.182 mmol) was added to the resultant solution. The
reaction mixture was stirred for 18 h at room temperature
and then diluted with EtOAc. After successive washing with
saturated NaHCO3 solution, saturated NH4Cl solution,
saturated NaHCO3 solution and brine, the organic layer
was dried with MgSO4 and evaporated. Purification of the
residue on silica gel (2:1 hexanes/EtOAc containing 1% of
NEt3) provided amide 35 as a colorless viscous oil (84 mg,
83% in two steps from 20); n2D6Z1.5160; [a]D27 K39.4
(c 1.11, CHCl3); IR (film): nmax 3390, 2928, 1732, 1667,
2.1.28. (2Z,20R,200E,30R,3000R,4S,400E,4000R,50S,5000R,60S,
7000S)-N-{60-[500-(4000-t-Butyldimethylsilyloxy-7000-methoxy-
7000-methyl-1000,6000-dioxaspiro[2.5]oct-5000-yl)-300-methyl-
penta-200,400-dien-100-yl]-20,50-dimethyltetrahydropyran-
30-yl}-4-hydroxypent-2-enamide (37). To a cooled
(K20 8C) solution of diene 36 (13.3 mg, 0.019 mmol) in
MeOH (0.5 mL) was added 0.05% HCl/MeOH solution
(0.5 mL) and the mixture was stirred for 10 h at this
temperature. The reaction was neutralized with triethyl-
amine (0.1 mL) and diluted with EtOAc. This solution was
washed with saturated NaHCO3 solution and brine, dried
with MgSO4 and then evaporated. Purification of the residue
by preparative TLC (1:3 hexanes/EtOAc) gave alcohol 37 as
a colorless oil (9.5 mg, 85%); [a]2D3 C83.7 (c 1.11, CHCl3);
IR (CHCl3 solution): nmax 3438, 3006, 1655, 1626, 1509,
1256 cmK1; 1H NMR (300 MHz, CDCl3): d (ppm) K0.04,
1
1633, 1331 cmK1; H NMR (300 MHz, CDCl3): d (ppm)
0.02, 0.04 (6H, two s, –SiMe), 0.76 (3H, d, JZ7.5 Hz,
50-CH3), 0.86 (9H, s, tBu), 0.97 (3H, d, JZ6.4 Hz, 20-CH3),
1.15–1.25 (1H, m, 50-H), 10.23 (3H, d, JZ6.6 Hz, 5-H), 1.55
(1H, dt, JZ14.5, 4.7 Hz, 4 -Ha), 1.65 (1H, br d, JZ14.5 Hz,
40-Hb), 1.86 (3H, s, 300-CH3), 2.02 (1H, m, 100-Ha), 2.16 (1H,
m, 100-Hb), 3.08 (1H, dt, JZ2.7, 7.2 Hz, 60-H), 3.26 (1H, dq,
JZ2.0, 6.4 Hz, 20-H), 3.76 (1H, m, 30-H), 4.14, 4.2000(2H,
two d, JZ13.8 Hz, 400-H), 5.29 (1H, t, JZ6.8 Hz, 2 -H),
5.48 (1H, dd, JZ1.4, 11.5 Hz, 2-H), 5.5–5.6 (2H, m, 4-H,
–NH–), 5.98 (1H, dd, JZ7.8, 11.5 Hz, 3-H), 7.55–7.65 (2H,
m, Har), 7.99 (1H, br d, JZ7.3 Hz, Har), 8.21 (1H, br d,
JZ7.3 Hz, Har); 13C NMR (75.5 MHz, CDCl3): d (ppm)
K4.8, K4.8, 14.8, 17.0, 17.7, 18.1, 23.7, 25.8, 28.6, 31.9,
35.6, 46.7, 64.3, 65.3, 75.8, 80.0, 119.0, 122.2, 124.0, 125.3,
127.7, 128.0, 133.2, 136.8, 151.0, 152.6, 165.0, 165.5;
HRMS (FAB) m/z Calcd for C30H47N2O5S2Si: 607.2696
(MCCH). Found: 607.2681.
t
0.01 (6H, two s, –SiMe), 0.83 (9H, s, Bu), 1.00 (3H, d,
JZ7.2 Hz, 50-CH3), 1.14 (3H, d, JZ6.3 Hz, 20-CH3), 1.34
(3H, d, JZ6.9 Hz, 5-H), 1.37 (3H, s, 7000-CH3), 1.71 (1H, d,
JZ14.3 Hz, 8000-Ha), 1.75–1.85 (1H, m, 50-H), 1.77 (3H, s,
300-CH3), 1.94 (2H, t, JZ3.3 Hz, 40-H), 2.23 (1H, d,

1388
H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
JZ14.3 Hz, 8000-Hb), 2.2–2.4 (2H, m, 100-H), 2.41 (1H, d, JZ
5.1 Hz, 2000-Ha), 2.88 (1H, d, JZ5.1 Hz, 2000-Hb), 3.24 (3H, s,
–OMe), 3.54 (1H, dt, JZ2.5, 0700.3 Hz, 60-H), 3.66 (1H, m, 20-
H), 3.68 (1H, d, JZ8.2 Hz, 4 -H), 3.94 (1H, m, 30-H), 4.29
(1H, t, JZ8.2 Hz, 5000-H), 4.78 (1H, m, 4-H), 5.44 (1H, t, JZ
7.1 Hz, 200-H), 5.54 (1H, dd, JZ8.2, 15.6 Hz, 500-H), 5.60
(1H, br d, JZ3.9 Hz, –OH), 5.71 (1H, d, JZ12.0 Hz, 2-H),
5.93 (1H, d, JZ9.3 Hz, –NH–), 6.18 (1H, dd, JZ5.4,
12.0 Hz, 3-H), 6.32 (1H, d, JZ15.6 Hz, 400-H); 13C NMR
(75.5 MHz, CDCl3): d (ppm) K4.4, K4.1, 12.5, 15.1, 17.8,
18.0, 22.7, 23.1, 25.6, 28.7, 31.8, 35.7, 42.9, 47.1, 47.5,
48.2, 57.2, 64.5, 69.5, 73.8, 75.8, 80.8, 98.8, 122.5, 124.4,
128.6, 134.6, 138.4, 150.8, 166.1; HRMS (FAB) m/z Calcd
for C32H56NO7Si: 594.3826 (MCCH). Found: 594.3818.
saturated NaHCO3 solution and brine, dried with MgSO4
and concentrated under reduced pressure. The residue was
purified by silica gel column chromatography (1:2–1:15
hexanes/EtOAc) to give alcohol 6 as a white powder
(44 mg, 97%); mp 65–70 8C; [a]2D1 C26.6 (c 0.87, CHCl3);
IR (KBr): nmax 3449, 2933, 1737, 1669, 1638, 1523 cmK1
;
1H NMR (300 MHz, CDCl3): d (ppm) 1.01 (3H, d,
JZ7.2 Hz, 50-CH3), 1.15 (3H, d, JZ6.4 Hz, 20-CH3), 1.38
(3H, s, 7000-CH3), 1.38 (3H, d, JZ6.3 Hz, 5-H), 1.73 (1H, d,
JZ14.7 Hz, 8000-Ha), 1.74–1.85 (2H, m, 50-H, –OH), 1.79
(3H, s, 300-CH3), 1.95 (2H, m, 40-H), 2.04 (3H, s,
–OCOCH3), 0020 .23 (1H, m, 100-Ha), 2.30 (1H, d,
JZ14.7 Hz, 8 -Hb), 2.39 (1H, m, 100-Hb), 2.49 (1H, d,
JZ4.5 Hz, 2000-Ha), 2.99 (1H, d, JZ4.5 Hz, 2000-Hb), 3.27
(3H, s, –OMe), 3.5200(0 1H, dt, JZ2.4, 7.1 Hz, 60-H), 3.60
(1H, t, JZ9.9 Hz, 4 -H), 3.66 (1H, dq, JZ2.0, 6.4 Hz,
2000-0H), 3.93 (1H, m, 30-H), 4.05 (1H, dd, JZ6.9, 9.9 Hz,
5 -H), 5.50 (1H, t, JZ7.1 Hz, 200-H), 5.65–5.73 (2H, m,
2-H, 500-H), 5.88 (1H, dd, JZ7.8, 11.7 Hz, 3-H), 6.00 (1H,
d, JZ9.0 Hz, –NH–), 6.25 (1H, m, 4-H), 6.40 (1H, d,
JZ15.6 Hz, 400-H); 13C NMR (75.5 MHz, CDCl3): d (ppm)
12.6, 15.0, 17.8, 20.0, 21.2, 23.0, 28.8, 31.9, 35.8, 42.0,
47.1, 48.4, 56.5, 67.5, 68.9, 73.2, 75.9, 80.8, 98.5, 122.5,
124.1, 128.9, 134.7, 138.1, 143.6, 164.8, 170.3; HRMS
(FAB) m/z Calcd for C28H44NO8: 522.3067 (MCCH). Found:
522.3070.
2.1.29. (2Z,20R,200E,30R,3000R,4S,400E,4000R,50S,5000R,60S,
7000S)-N-{60-[500-(4000-t-Butyldimethylsilyloxy-7000-methoxy-
7000-methyl-1000,6000-dioxaspiro[2.5]oct-5000-yl)-300-methyl-
penta-200,400-dien-100-yl]-20,50-dimethyltetrahydropyran-
30-yl}-4-acetoxypent-2-enamide (38). To a cooled (0 8C)
solution of alcohol 37 (19.8 mg, 0.033 mmol), triethylamine
(28 mL, 0.200 mmol) and DMAP (4.1 mg, 0.033 mmol) in
dichloromethane (0.4 mL) was added acetic anhydride
(9.4 mL, 0.100 mmol) and this mixture was stirred for
1.5 h at this temperature. The reaction mixture was poured
into water and extracted with EtOAc. The organic layer was
washed with saturated NaHCO3 solution and brine, dried
with MgSO4 and then evaporated. Purification of the residue
by preparative TLC (1:1 hexanes/EtOAc) yielded acetate 38
as a colorless oil (20.7 mg, 98%); [a]2D1 C24.6 (c 1.00,
CHCl3); IR (CHCl31solution): nmax 3441, 2930, 1732, 1670,
1646, 1504 cmK1; H NMR (300 MHz, CDCl3): d (ppm)
K0.03, 0.01 (6H, two s, –SiMe), 0.84 (9H, s, tBu), 1.00 (3H,
d, JZ7.5 Hz, 50-CH3), 1.15 (3H, d, JZ6.3 Hz, 20-CH3),
1.37 (3H, s, 7000-CH3), 1.39 (3H, d, JZ6.6 Hz, 5-H), 1.71
(1H, d, JZ14.3 Hz, 8000-Ha), 1.7–1.8 (1H, m, 50-H), 1.77
(3H, s, 300-CH3), 1.95 (2H, m, 40-H), 2.04 (3H, s,
–OCOCH3), 2.23 (1H, d, JZ14.3 Hz, 8000-Hb), 2.2–2.4
(2H, m, 100-H), 2.41 (1H, d, JZ5.1 Hz, 2000-Ha), 2.88 (1H, d,
JZ5.1 Hz, 2000-Hb), 3.25 (3H, s, –OMe), 3.52 (1H, dt,
JZ2.1, 7.1 Hz, 60-H), 3.66 (1H, m, 20-H), 3.68 (1H, d,
JZ8.3 Hz, 4000-H), 3.94 (1H, m, 30-H), 4.30 (1H, br t,
JZ8.3 Hz, 5000-H), 5.45 (1H, t, JZ6.9 Hz, 200-H), 5.54 (1H,
dd, JZ8.3, 15.6 Hz, 500-H), 5.70 (1H, d, JZ11.6 Hz, 2-H),
5.89 (1H, dd, JZ8.0, 11.6 Hz, 3-H), 5.98 (1H, d, JZ9.0 Hz,
–NH–), 6.26 (1H, m, 4-H), 6.32 (1H, d, JZ15.6 Hz, 400-H);
13C NMR (75.5 MHz, CDCl3): d (ppm) K4.4, K4.1, 12.5,
15.0, 17.8, 18.1, 19.9, 21.2, 23.1, 25.7, 28.8, 31.9, 35.8,
42.9, 47.0, 47.1, 48.2, 57.2, 68.9, 69.5, 73.8, 75.9, 80.8,
98.8, 122.4, 124.3, 128.8, 134.5, 138.5, 143.7, 164.8, 170.3;
HRMS (FAB) m/z Calcd for C34H58NO8Si: 636.3932
(MCCH). Found: 636.3936.
2.1.31. (2Z,20R,200E,30R,3000R,4S,400E,4000R,50S,5000R,60S,
7000S)-N-{60-[500-(4000,7000-Dihydroxy-7000-methyl-1000,6000-
dioxaspiro[2.5]oct-5000-yl)-300-methylpenta-200,400-dien-100-
yl]-20,50-dimethyltetrahydropyran-30-yl}-4-acetoxypent-
2-enamide (1, FR901464). To a cooled (0 8C) solution of 6
(28.4 mg, 0.054 mmol) in THF–water (4:1, 3.5 mL) was
added Amberlyst 15 (40 mg). This mixture was gradually
warmed up to room temperature and stirred for 20 h. The
reaction was neutralized with triethylamine (0.2 mL), dried
briefly with Na2SO4 and directly purified by silica gel
column chromatography (1:3 hexanes/EtOAc—EtOAc
only) to some degree. This crude product was further
purified by preparative HPLC (2:3 water/MeOH) to give 1
as a white powder (9.9 mg, 36%) and unreacted starting
material (6.0 mg). The yield was calculated to be 45% based
on the recovered starting material. Finally, a small amount
of this material was finely purified by recrystallization from
hexane for analytical purposes; mp 65–70 8C; [a]2D4 K14.1
(c 0.50, CH2Cl2); IR (KBr): nmax 3448, 2925, 1736, 1666,
1
1634, 1523 cmK1; H NMR (500 MHz, CD2Cl2): d (ppm)
1.01 (3H, d, JZ7.5 Hz, 50-CH3), 1.11 (3H, d, JZ6.3 Hz,
20-CH3), 1.34 (3H, d, JZ7.0 Hz, 5-H), 1.43 (3H, s, 7000-CH3),
1.61 (1H, d, JZ9.6 Hz, 4000-0OH), 1.64 (1H, d, 00JZ14.5 Hz,
8000-Ha), 1.72–1.82 (1H, m, 5 -H), 1.78 (3H, s, 3 -CH3), 1.92
(2H, m, 40-H), 2.01 (3H, s, –OCOCH3), 2.23 (1H, m, 100-Ha),
2.34 (1H, d, JZ14.5 Hz, 8000-Hb), 2.36 (1H, m, 100-Hb), 2.55
(1H, d, JZ4.5 Hz, 2000-Ha), 3.06 (1H, d, JZ4.5 Hz, 2000-Hb),
3.33 (1H, s, 7000-OH), 3.53 (1H, m, 60-H), 3.57 (1H, t,
JZ9.6 Hz, 4000-H), 3.66 (1H, dq, JZ2.3, 6.3 Hz, 20-H), 3.90
(1H, m, 30-H), 4.24 (1H, dd, JZ7.0, 9.6 Hz, 5000-H), 5.54
(1H, br t, JZ7.0 Hz, 200-H), 5.65 (1H, dd, JZ7.0, 15.5 Hz,
500-H), 5.71 (1H, dd, JZ1.8, 11.6 Hz, 2-H), 5.90 (1H, dd,
JZ8.0, 11.6 Hz, 3-H), 5.98 (1H, d, JZ8.5 Hz, –NH–), 6.26
(1H, m, 4-H), 6.38 (1H, d, JZ15.5 Hz, 400-H); 13C NMR
(125 MHz, CD2Cl2): d (ppm) 12.7, 15.2, 17.9, 20.2, 21.4,
29.1, 29.5, 32.3, 36.2, 41.8, 47.3, 48.1, 58.1, 68.1, 68.9,
2.1.30. (2Z,20R,200E,30R,3000R,4S,400E,4000R,50S,5000R,60S,
7000S)-N-{60-[500-(4000-Hydroxy-7000-methoxy-7000-methyl-
1000,6000-dioxaspiro[2.5]oct-5000-yl)-300-methylpenta-200,400-
dien-100-yl]-20,50-dimethyltetrahydropyran-30-yl}-4-
acetoxypent-2-enamide (6, FR901464 methyl acetal). To
a cooled (K10 8C) solution of 38 (55 mg, 0.086 mmol) in
THF (1 mL) was added TBAF (260 mL of 1.0 M in THF,
0.260 mmol) and this mixture was stirred for 3 h at 0 8C.
The resultant solution was poured into water and extracted
with EtOAc. The combined organic layer was washed with

H. Motoyoshi et al. / Tetrahedron 62 (2006) 1378–1389
1389
9. Avenoza, A.; Cativiela, C.; Peregrina, J. M.; Zurbano, M. M.
Tetrahedron: Asymmetry 1997, 8, 863–871.
73.8, 76.2, 81.1, 96.7, 122.8, 124.6, 129.9, 134.8, 138.3,
143.8, 164.9, 170.6; HRMS (FAB) m/z Calcd for
C27H42NO8: 508.2910 (MCCH). Found: 508.2908.
10. Scheibye, S.; Kristensen, J.; Lawesson, S.-O. Tetrahedron
1979, 35, 1339–1343.
11. For examples of Wittig reactions on thioamides and O,O-
dimethyl ethanebis(thiolate), see: (a) Hartke, K.; Kumar, A.;
Koester, J. Liebigs Ann. Chem. 1983, 267–273. (b) Slopianka,
M.; Gossauer, A. Liebigs Ann. Chem. 1981, 2258–2265. (c)
Gossauer, A.; Roessler, F.; Zilch, H.; Ernst, L. Liebigs Ann.
Chem. 1979, 1309–1321. (d) Gossauer, A.; Hinze, R.-P.;
Zilch, H. Angew. Chem., Int. Ed. Engl. 1977, 16, 418.
12. (a) Loibner, H.; Zbiral, E. Helv. Chim. Acta 1976, 59,
2100–2113. (b) Mitsunobu, O. Synthesis 1981, 1–28.
13. Schultz, H. S.; Freyermuth, H. B.; Buc, S. R. J. Org. Chem.
1963, 28, 1140–1142.
Acknowledgements
The authors sincerely thank Dr. Hidenori Nakajima,
Fujisawa Pharmaceutical Co., Ltd, for a kind gift of natural
FR901464 and its spectral charts. This work was financially
supported by a Grant-in-Aid for Scientific Research from
the Japanese Ministry of Education, Culture, Sports,
Science and Technology, and also supported by Sankyo
Foundation of Life Science, and Suntory Institute for
Bioorganic Research. We also thank Ms. Hiroko Naito,
The University of Tokyo, for elemental analyses, and
Dr. Kazuo Sin-ya, The University of Tokyo, for mass
spectroscopy.
14. Massad, S. K.; Hawkins, L. D.; Baker, D. C. J. Org. Chem.
1983, 48, 5180–5182.
15. (a) Annunziata, R.; Cinquini, M.; Cozzi, F.; Dondio, G.;
Raimondi, L. Tetrahedron 1987, 43, 2369–2380. (b) Still, W. C.;
Gennari, C. Tetrahedron Lett. 1983, 24, 4405–4408.
16. Horton, D.; Markovs, R. A. Carbohydr. Res. 1980, 78,
295–303.
References and notes
17. Compound 25 was initially prepared by our original method.3
However, we found out known compound 24 from Ref. 16,
therefore we decided to start synthesis of segment C from triol
24.
1. (a) Nakajima, H.; Sato, B.; Fujita, T.; Takase, S.; Terano, H.;
Okuhara, M. J. Antibiot. 1996, 49, 1196–1203. (b) Nakajima,
H.; Hori, Y.; Terano, H.; Okuhara, M.; Manda, T.; Matsumoto,
S.; Shimomura, K. J. Antibiot. 1996, 49, 1204–1211.
2. Nakajima, H.; Takase, S.; Terano, H.; Tanaka, H. J. Antibiot.
1997, 50, 96–99.
18. (a) Dess, D. B.; Martin, J. C. J. Am. Chem. Soc. 1991, 113,
7277–7287. (b) Ireland, R. E.; Liu, L. J. Org. Chem. 1993, 58,
2899.
3. (a) Horigome, M.; Motoyoshi, H.; Watanabe, H.; Kitahara, T.
Tetrahedron Lett. 2001, 42, 8207–8210. For our previous
synthetic study, also see:. (b) Horigome, M.; Watanabe, H.;
Kitahara, T. Tennen Yuki Kagobutsu Toronkai Koen Yoshishu
1999, 41, 73–78. (c) Chem. Abstr. 2000, 132, 676.
4. Motoyoshi, H.; Horigome, M.; Ishigami, K.; Yoshida, T.;
Horinouchi, S.; Yoshida, M.; Watanabe, H.; Kitahara, T.
Biosci. Biotechnol. Biochem. 2004, 68, 2178–2182.
5. For other synthetic studies, see: (a) Thompson, C. F.;
Jacobsen, E. N. J. Am. Chem. Soc. 2000, 122, 10482–10483.
(b) Thompson, C. F.; Jamison, T. F.; Jacobsen, E. N. J. Am.
Chem. Soc. 2001, 123, 9974–9983. (c) Albert, B. J.; Koide, K.
Org. Lett. 2004, 6, 3655–3658.
19. (a) Pine, S. H.; Zahler, R.; Evans, D. A.; Grubbs, R. H.
J. Am. Chem. Soc. 1980, 102, 3270–3272. (b) Tebbe, F. N.;
Parshall, G. W.; Reddy, G. S. J. Am. Chem. Soc. 1978, 100,
3611–3613.
20. Horita, K.; Yoshioka, T.; Tanaka, T.; Oikawa, Y.; Yonemitsu,
O. Tetrahedron 1986, 42, 3021–3028.
21. Mai, K.; Patil, G. J. Org. Chem. 1986, 51, 3545–3548.
22. (a) Griffith, W. P.; Ley, S. V. Aldrichim. Acta 1990, 23, 13–19.
(b) Ley, S. V.; Norman, J.; Griffith, W. P.; Marsden, S. P.
Synthesis 1994, 639–666.
23. HBTU stands for O-benzotriazol-1-yl-N,N,N0,N0-tetramethyl-
uronium hexafluorophosphate. Dourtoglou, V.; Gross, B.
Synthesis 1984, 572–574.
6. Garner, P.; Park, J. M. J. Org. Chem. 1987, 52, 2361–2364.
7. Katsuki, T.; Sharpless, K. B. J. Am. Chem. Soc. 1980, 102,
5974–5976.
24. In this reaction, a small amount (5–10%) of by-product, in
which side reaction was thought to have occurred at nitrogen
of the amide moiety, was obtained. This compound was
readily separated by preparative HPLC.
8. Baudin, J. B.; Hareau, G.; Julia, S. A.; Ruel, O. Tetrahedron
Lett. 1991, 32, 1175–1178.