Total Synthesis and Biological Evaluation of Ipomoeassin F and Its Unnatural 11R-Epimer

Article abstract of DOI:10.1021/acs.joc.5b01765

Ipomoeassin F, a macrolide glycoresin containing an embedded disaccharide, possesses potent in vitro antitumor activity with an unknown mechanism of function. It inhibits tumor cell growth with single-digit nanomolar IC₅₀ values, superior to many clinical chemotherapeutic drugs. To facilitate translation of its bioactivity into protein function for drug development, we report here a new synthesis for the gram-scale production of ipomoeassin F (3.8% over 17 linear steps) from commercially available starting materials. The conformation-controlled subtle reactivity differences of the hydroxyl groups in carbohydrates were utilized to quickly construct the disaccharide core, which, along with judicial selection of protecting groups, made the current synthesis very efficient. The same strategy was also applied to the smooth preparation of the 11R-epimer of ipomoeassin F for the first time. Cytotoxicity assays demonstrated the crucial role of the natural 11S configuration. In addition, cell cycle analyses and apoptosis assays on ipomoeassin F and/or its epimer were conducted. This work has laid a solid foundation for understanding the medicinal potential of the ipomoeassin family of glycolipids in the future.

Full text of DOI:10.1021/acs.joc.5b01765

Subscriber access provided by UNIV OF CAMBRIDGE
Article
Total Synthesis and Biological Evaluation of
Ipomoeassin F and Its Unnatural 11R-Epimer
Guanghui Zong, Eric Barber, Hazim Aljewari, Jianhong Zhou, Zhijian Hu, Yuchun Du, and Wei Q. Shi
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.5b01765 • Publication Date (Web): 28 Aug 2015
Downloaded from http://pubs.acs.org on September 3, 2015
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a free service to the research community to expedite the
dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts
appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been
fully peer reviewed, but should not be considered the official version of record. They are accessible to all
readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered
to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published
in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just
Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor
changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers
and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors
or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
The Journal of Organic Chemistry is published by the American Chemical Society.
1155 Sixteenth Street N.W., Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
Total Synthesis and Biological Evaluation of Ipomoeassin
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
F and Its Unnatural 11R-Epimer
Guanghui Zong,† Eric Barber,† Hazim Aljewari,† Jianhong Zhou,‡ Zhijian Hu,† Yuchun Du,‡ and Wei Q.
Shi*,†
†Department of Chemistry and Biochemistry, and ‡Department of Biological Sciences, J. William
Fulbright College of Arts & Science, University of Arkansas, Fayetteville, Arkansas, 72701, USA
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 2 of 38
1
2
3
4
Table of Content Graphic
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ACS Paragon Plus Environment

Page 3 of 38
The Journal of Organic Chemistry
1
2
3
4
ABSTRACT
5
6
7
8
9
Ipomoeassin F, a macrolide glycoresin containing an embedded disaccharide, possesses potent in vitro
antitumor activity with an unknown mechanism of function. It inhibits tumor cell growth with single-
digit nanomolar IC50 values, superior to many clinical chemotherapeutic drugs. To facilitate translation of
its bioactivity into protein function for drug development, we report here a new synthesis for the gram-
scale production of ipomoeassin F (3.8% over 17 linear steps) from commercially-available starting
materials. The conformation-controlled subtle reactivity differences of the hydroxyl groups in
carbohydrates were utilized to quickly construct the disaccharide core, which, along with judicial
selection of protecting groups, made the current synthesis very efficient. The same strategy was also
applied to the smooth preparation of the 11R-epimer of ipomoeassin F for the first time. Cytotoxicity
assays demonstrated the crucial role of the natural 11S configuration. In addition, cell cycle analyses and
apoptosis assays on ipomoeassin F and/or its epimer were conducted. This work has laid a solid ground
for understanding the medicinal potential of the ipomoeassin family of glycolipids in the future.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 4 of 38
1
2
3
4
INTRODUCTION
5
6
7
8
Resin glycosides (also called glycoresins) are a large collection of amphiphilic glycolipids consisting of a
differently-acylated oligosaccharide glycosylated with a mono- or dihydroxy C14 or C16 fatty acid.1,2 The
latter is usually folded back to form a macrolactone ring of various sizes spanning two or more sugar
units. Resin glycosides are primarily isolated from the morning glory family (Convolvulaceae) of plants
that have been extensively used as traditional herbal medicines for many diseases. Because of their
unique macrocyclic architectures with embedded carbohydrates and a broad spectrum of biological
activities, resin glycosides have attracted considerable attention from the synthetic community, but not
much beyond.3-5
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
In 2005 and 2007, a new family of glycoresins, ipomoeassins A–F (Table 1), was isolated from the
leaves of Ipomoea squamosa in the Suriname rainforest.6,7 These newly discovered natural
glycoconjugates quickly inspired synthetic chemists to tackle their total syntheses8 because two members
of the family, ipomoeassins D and F, exhibited exceptionally potent cytotoxicity with single-digit
nanomolar IC50 values against several cancer cell lines (Table 1). More importantly, in the NCI 60-cell
line screen, the naturally most abundant member of the family, ipomoeassin A, showed strong and
selective growth inhibition of different cancer cells, and its pattern of activity was clearly distinguished
from other known anticancer agents based on a COMPARE analysis.9 Therefore, it suggests that the
ipomoeassins have novel molecular targets and can serve as promising new leads for developing a new
class of anti-neoplastic agents.
Table 1. Structures and IC50 values of ipomoeassin A–F.
Structure
IC50 (nM)
Ipomoeassin
MDA-
MB-435
R1
R2
n
HeLa L-929 A2780 U937 HT-29
H522-T1
A
B
C
D
E
F
H
H
Ac
H
1
1
1
1
1
3
64
77.8
500
400
20.2
134
46.1
396
42.6
108.9
1070
2500
2700
OH Ac
OAc Ac
1500 > 1000 2900
32 135 35
4300 > 1000 3300
7.4 36
7.9
163
2.6
11.8
393
4.2
19.9
1633
9.4
23.2
967
OAc
H
H
Ac
12.9
With the long-term goal of utilizing underexploited natural glycoconjugates to study biological
systems for drug development, our laboratory became enamored with the ipomoeassin family of
glycolipids for both chemical and biological reasons. Chemically, it is still necessary to develop more
scalable and flexible syntheses of the ipomoeassins and their analogs to offer solutions to the scarce
availability. From a biological vantage point, we are interested in biological assessment of those
chemical entities resulting from such efforts, which would open the door to understanding the mechanism
ACS Paragon Plus Environment

Page 5 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
of action of the ipomoeassins and may eventually lead to new therapeutic and/or preventative
interventions. Ipomoeassin F was selected as a representative compound in this venture because it
showed the highest activity in the family.
7
To date, two total syntheses of ipomoeassin F have been achieved independently by Postema10 and
Fürstner.11 Given its favorable reactivity profile and high flexibility, RCM12,13 was adopted by both
groups for the formation of the 20-membered macrolactone ring. RCM has demonstrated great success
for the syntheses of many resin glycosides;4,5 however, incompatibility between two unsaturated ester
groups (cinnamate and tiglate at 4-O-Glcp (glucosylpyranoside) and 3-O-Glcp, respectively) and
common hydrogenation conditions presented a substantial challenge in protecting group maneuver for the
ipomoeassin F syntheses. To solve this problem, the Fürstner group found that trisubstituted alkenes can
well survive hydrogenation catalyzed by Wilkinson’s catalyst; therefore, they elegantly designed the key
intermediate 1 (Chart 1) with a C-silylated cinnammic acid ester and achieved the total synthesis of
ipomoeassin F in ~1.0% overall yield.11 By contrast, Postema and his coworkers decided to go through
the orthogonally-protected intermediate 2 (Chart 1), thereby postponing the assembly of both cinnamate
and tiglate to a later stage after RCM and hydrogenation. Intermediate 2 offers great flexibility for
synthesizing ipomoeassin F analogs. Unfortunately, the total yield for this route is only ~0.4%.10
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Chart 1. Key intermediates in the previous total syntheses of
ipomoeassin F (Fürstner and Postema).
Because of the critical role of the disaccharide core, the sequence for the installation of its peripheral
ester functional groups, in particular the cinnamate moiety, is crucial to the overall efficiency for
synthesizing ipomoeassin F. In addition, we were attracted by this sole aromatic functionality of
cinnamate for two other reasons. First, cinnamoyl-containing compounds classified as phenylpropanoids
have received significant attention in medicinal research as antitumor agents.14 Second, we hypothesized
that the disubstituted α,β-unsaturated Michael system in the cinnamate group could be a covalent protein
modifier through 1,4-nucleophilic addition.15 In order to conduct efficient SAR studies to clarify the role
of the cinnamic ester in the future, it is essential to introduce this moiety as late as possible. Based on this
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 6 of 38
1
2
3
4
principle, this full account traces the evolution of our studies that enabled the scalable synthesis and
5
6
biological evaluation of ipomoeassin F and its 11R-epimer.
7
8
RESULTS AND DISCUSSION
9
Strategic Considerations. Because of the high efficiency of RCM in making macrocycles, we
decided to continue to incorporate it in our strategy (Scheme 1). However, the requirement for
hydrogenation after RCM along with the presence of a variety of ester moieties in ipomoeassin F makes
the choice of protecting groups very limited because of orthogonality issues. Thus, TBS groups were
selected and a new diene intermediate 9a with minimal transient protections was designed. Using 9a, the
introduction of the cinnamate moiety could be postponed right after RCM and hydrogenation
(intermediate 10a), which would lead to ipomoeassin F after the removal of TBS. To make the synthesis
even more challenging, the β-(1→2) linkage further limits the choice of the protecting group on 2-O-Glcp
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Scheme 1. Retrosynthesis of Ipomoeassin F.
to those with the neighboring group participation effect. Therefore, the monosaccharide building blocks,
3 and 6a, were proposed. In the glucosyl donor 3, tiglate was introduced in an early stage to minimize the
number of protection and deprotection steps. The requirement of a participating group for β-glycosylation,
which is also orthogonal to esters, made us opt for the allyloxycarbonyl (Alloc) group as a transient
protection because its mild deprotection conditions could be well tolerated by many functional groups.16
To prepare 3, the reactivity difference between 2-OH-Glcp and 3-OH-Glcp was investigated and
exploited.17 Similarly, by exploiting the reactivity differences of the hydroxyl groups in a pyranose ring,17
the fucosyl acceptor 6a was designed with minimal protection steps from fucosyl donor 418 and chiral
alcohol 5a.11 The regioselective TBS protection on 3-OH-Fucp (fucosylpyranoside), followed by the
regioselective glycosylation on the equatorial 2-OH-Fucp in 6a and then acetylation on the 4-OH-Fucp,
ACS Paragon Plus Environment

Page 7 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
afforded the disaccharide 7a, which led to the diene intermediate 9a after replacement of Alloc with TBS,
followed by deisopropylidenation and consequent chemo-selective esterification of 6-OH-Glcp with 4-
oxo-8-nonenoic acid 8.19
7
8
9
To the best of our knowledge, the stereochemistry for the fatty acid carbon that is connected to the
carbohydrate core of a natural resin glycoside through the glycosydic bond is exclusively the S
configuration. In ipomoeassin F, we believe that this sole stereogenic center of the aglycone has great
influence on the overall conformation of the molecule, only second to the sugar core. Although it is a
reasonable assumption that the naturally-occurring S configuration would be preferred for biological
activities, no experimental evidence has been documented in literature as yet. Therefore, we also include
the 11R-epimer of ipomoeassin F in our studies by using the same strategy.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Synthesis of Glucosyl Donor 3. The synthesis commenced with the preparation of D-glucosyl donor
3 (Scheme 2). For esterification, it has been found that the 3-OH is more active than 2-OH in the case of
Scheme 2. Regioselective Acylation at 2-OH and 3-OH of β-D-Glucoside (13) and α-D-Glucoside
(18) and Synthesis of Glucosyl Donor 3
β-D-glucopyranoside.17 Therefore, we first tried to introduce tiglate to the 3-O position of p-
methoxyphenyl (PMP)-β-D-glucopyranoside (13)20,21 utilizing Steglich esterification.22 Unexpectedly, we
got a mixture of products in which 2-O-tiglate was the major product in the ratio of 2.4:1 for 2-O-tiglate
versus 3-O-tiglate. Because it has also been found that regioselective esterification favored 2-OH in an α-
glucopyranoside,17 we next explored the selectivity for installing Alloc on the 2-OH of α-glucopyranoside
18, which was obtained through isopropylidenation of p-methoxylphenyl-α-D-glucopyranoside 17.23 To
our delight, we got exclusive selectivity on 2-O-Glcp position with a yield of 86% when treated with
AllocCl at low temperature (Scheme 2, Route 2). The resulting compound 19 was subsequently acylated
with tiglic acid to give an excellent yield of glucosyl donor precursor 20 (95%). Cleavage of the 4-
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 8 of 38
1
2
methoxyphenyl group in 20 with CAN, followed by the reaction with trichloroacetonitrile and DBU,24
gave the trichloroacetimidate donor 3 in 59% yield over two steps.
3
4
5
6
Synthesis of Fucoside Acceptor 6a/b. The synthetic route for fucoside acceptor 6a/b is outlined in
Scheme 3. The known fucosyl donor 418 was prepared in 77% yield from compound 2125 using a two-step
sequence involving selective removal of anomeric acetate followed by trichloroacetimidate formation.
Glycosylation of fucosyl donor 4 with (S)- or (R)-4-hydroxy-1-nonene (5a11 or 5b) was accomplished by
using TMSOTf as the catalyst in the presence of 4Å molecular sieves, which then underwent global
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Scheme 3. Preparation of Fucoside Acceptor 6a
deacetylation to give triol 23a10 or 23b in good to excellent yield over two steps. In the literature,17 it has
been established that in the galacto-configuration, the reactivity order for the secondary hydroxyl groups
is 3-OH > 2-OH > 4-OH. The 3-OH is most nucleophilic because of the hydrogen bonding with axial 4-
OH. Therefore, we applied this rationale to 6-deoxy galactopyranose (D-fucose) to selectively protect 3-
OH. Thankfully, regioselective silylation on 3-OH of the triol 23a/b with TBSCl provided the diol
product in good yield (72% for 6a and 71% for 6b). The regioselectivity was confirmed by acetylation of
6a to give 24 (92%). Both 1H and COSY NMR spectra of 24 showed the signals for H-2 and H-4 moving
downfield, while a doublet of doublet peak stays at δ 3.78 ppm with J2,3 = 9.6 and J3,4 = 3.6 Hz for H-3,
when compared to that of 6a. This single-step regioselective silylation without using any other protecting
groups significantly improved the overall efficiency of our synthesis.
ACS Paragon Plus Environment

Page 9 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
Synthesis of Diene Intermediate 9a/b. With the glucosyl donor 3 and the fucoside acceptor 6a/b in
hand, the diene 9a/b was prepared efficiently as outlined in Scheme 4. The regioselective Schmidt
o
glycosylation24 of acceptor 6a/b and donor 3 in dichloromethane at –60 C in presence of TMSOTf,
7
8
9
followed by acetylation of the remaining hydroxyl group, showed excellent regio- and stereoselectivity,
giving exclusively β-(1→2)-linked disaccharide 7a in 71% yield or 7b in 51% yield over 2 steps. The
configuration of the glycosyl bond and the regioselectivity of the coupling reaction were confirmed by the
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Scheme 4. Synthesis of Diene 9a/b
1H, COSY and HSQC NMR spectra. Using 7a as the example, although the signal for H-1-Glcp
overlapped with the signals for the terminal alkenes of the Alloc and the lipophilic tether, the coupling
constant for H-2-Glcp (J = 9.6, 8.0 Hz) indicates the β-linkage; a signal at 3.90 ppm (dd, 1H, J1,2 = 9.2,
8.0 Hz, 2-H-Fucp) and a signal at 5.00 ppm (m, 1H, H-4-Fucp, 4-O-Fucp acetylated) confirmed the
(1→2)-linkage of the disaccharide. The subsequent selective removal of the Alloc group was achieved in
the presence of CH3COONH4, Pd[P(C6H5)3]4, and NaBH4 in 95% yield within 4 min.16 The treatment of
the resulting alcohol with TBSOTf and 2,6-lutidine afforded the desired silyl ether 27a as the major
product (66%), and also a byproduct 28a, in which the tigloyl group in glucose migrated from 3-O-Glcp
to 2-O-Glcp and the TBS group was introduced to the 3-O-Glcp position. The structure of each isomer
was confirmed by the 1H, 13C, COSY, HSQC and HMBC NMR spectra (Figure 1). The separation of 27b
from 28b was not possible. The removal of the isopropylidene group using camphor-10-sulfonic acid
(CSA) followed by the chemoselective esterification of 6-OH-Glcp with 4-oxo-8-nonenoic acid 819 in the
presence of DCC and DMAP, gave diene as the RCM precursor (70% for 9a and 55% for 9b) over 2 steps.
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 10 of 38
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 1. Key COSY (bold) and HMBC (arrows) correlations in 27a and 28a.
Total Synthesis of Ipomoeassin F and its 11R-Epimer. Treatment of the diene 9a/b with Hoveyda-
Grubbs catalyst (II)26,27 (10 mol%) furnished macrolide a/b as a mixture of E/Z isomers, which was
subjected to hydrogenation over Wilkinson’s catalyst to give 10a/b as the major product (79%) (Scheme
5). In the penultimate step, the cinnamate moiety was introduced in 80% yield by reacting 10a/b with
Scheme 5. Completion of the Total Synthesis
cinnamoyl chloride in a pyridine solution promoted by DMAP. We also tried to use Steglich
esterification to introduce the cinnamate moiety and found that increasing concentration of the reactants
could further improve the synthesis up to 88% yield in 12 h for 10a. The final removal of the TBS groups
was achieved by treating 31a either with TBAF and AcOH at room temperature to give ipomoeassin F in
88% yield or with TBAF alone at low temperature to give ipomoeassin F in 82% yield. Its H and 13C
1
NMR spectra are consistent with the published literature data.7,10,11 Thus, ipomoeassin F was synthesized
in 3.8% overall yield over 17 steps of the longest linear sequence from commercially available starting
materials 11 and 21, which is more efficient (9- and 4-fold) than the previously reported two syntheses (ca.
0.4%10 and 1.0%11 overall yield, respectively, calculated based on the non-commercially available starting
materials).
In our route, three highly regioselective reactions were developed: a) selective
allyloxycarbonylation of the 2-OH-Glcp in diol 18; b) selective silylation of the 3-OH-Fucp in triol 23a;
and c) selective glycosylation of 2-OH-Fucp in diol 6a. To our delight, all of them were accomplished in
good to excellent yield (86%, 72% and 93%, respectively). Using this route, ipomoeassin F can be
ACS Paragon Plus Environment

Page 11 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
synthesized on a gram scale since the key intermidiate 10a was prepared on a scale of 1.6 grams.
Similarly, the 11R-epimer of ipomoeassin F was prepared from 31b.
Cytotoxicity of Ipomoeassin F. By using the MTT (3-(4,5 dimethylthiazol-2-yl)-2,5-
7
8
9
diphenyltetrazolium bromide) colorimetric assay28 with taxol as the positive control, the cytotoxicity of
ipomoeassin F obtained through our total synthesis was evaluated against a small panel of cell lines,
including five human tumor cell lines, one immortalized normal human mammary epithelial cell line
(MCF-10A), and one immortalized normal mouse embryo fibroblast cell line (NIH/3T3). The U937
human leukemic monocyte lymphoma cell line was selected for comparison with the literature-reported
cytotoxicity data.10,11 All the other cell lines, especially the two non-tumor cell lines, were screened for
the first time. The results presented in Table 2 illustrate the concentrations required for 50% cell death
(IC50 values) when compared to the vehicle-treated negative control. The IC50 values for ipomoeassin F
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Table 2. Cell Cytotoxicity (IC50 nM)a, b of Ipm Fc and Taxol
MDA-MB-
MCF7
HeLa
U937
Jurkat
MCF-10A NIH/3T3
231
d
Ipm F10,11
Ipm F
Epimer
Taxol
–
–
–
2.6e
5.4
190.1
2.7
–
6.1
325.1
2.8
–
–
6.5
240.2
5.1
43.7
830.7
11.0
16.4
440.2
1.6
5.4
16.8
159.2
41.0
1370.5
344.0
a 3-day treatment; b The data were obtained from at least two independent experiments, and the
standard errors are within 20%; c Ipm = ipomoeassin; d “–” = not tested; e 4/5-day treatment.
range from 5.4 nM to 43.7 nM, close to taxol, whereas the 11R-epimer is significantly (20–80 fold) less
active. In particular, the IC50 value (5.4 nM) for U937 cells is comparable to the literature-reported value
(2.6 nM),10,11 which further confirms the success of our synthesis. The 2-fold difference could be
explained by the longer treatment time in the literature conditions. In addition, ipomoeassin F exhibited
markedly different toxicity (~8-fold) against two cancer cell lines (U937 and MCF7), suggesting that the
cytotoxicity of ipomoeassin F is selective. Although taxol had lower IC50 values, the cell viability curves
Figure 2. Cytotoxic Effect of Synthetic Ipomoeassin F and Taxol on MDA-MB-231 cells.
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 12 of 38
1
2
3
4
5
6
showed that ipomoeassin F could inhibit cell growth to a 20-30% greater extent than taxol at
concentrations over 100 nM. One representative example is shown in Figure 2. Unfortunately, no
selectivity between tumor and non-tumor cell lines was observed for ipomeassin F.
7
8
9
Ipomoeassin F Induces G1 Cell Cycle Arrest. To date, very little is known about the functional
mechanism of the ipomoeassins. The only related biological studies that have been performed are cell
cycle analyses.11 The published data showed that a 24-hour treatment with the ipomoeassins led to the G1
arrest of mouse L-929 fibroblast cells, accompanied by a decreased cell number in the G2/M phase. The
continued (48 h) exposure caused a significant number of sub-G1 cells and apoptosis. To explore the
potential mechanism of action of ipomoeassin F in human cells, U937 cells were treated with
ipomoeassin F (90 nM) for 48 h and then the cell cycle was analyzed by flow cytometry after the cells
were stained by propidium iodide (PI). Consistent with the previous report, the ipomoeassin F treatment
resulted in significant G1 arrest (~25%, Figures 3A and 3B), which was accompanied by a decreased cell
population in both S and G2/M phase. In particular, the cell population in the G2/M phase was reduced
by ~21%.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
A
B
Figure 3. Ipomoeassin F induces G1 arrest in U937 cells. Human U937 cells were (A) mock-treated
or (B) treated with ipomoeassin F (90 nM). After 48 h, the cells were harvested, stained with
propidium iodide (PI) and analyzed by flow cytometry.
Ipomoeassin F Induces Apoptosis. To determine whether ipomoeassin F may kill cancer cells
through apoptosis, the U937 cells treated with ipomoeassin F (90 nM) for 48 h were stained with both
propidium iodide (PI) and FITC-conjugated annexin V, and then analyzed by flow cytometry.29 The
results demonstrated that the ipomoeassin F treatment induced a substantial increase in cell apoptosis: the
percentage of apoptotic cells increased from 13.2% (3.99% + 9.17%, Figure 4A) in control cells to 33.6%
(16.13% +17.46%, Figure 4B) in the ipomoeassin F-treated cells.
ACS Paragon Plus Environment

Page 13 of 38
The Journal of Organic Chemistry
1
2
3
4
A
B
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 4. Ipomoeassin F induces apoptosis in U937 cells. Human U937 cells were (A) mock-
treated or (B) treated with ipomoeassin F (90 nM). After 48 h, the cells were harvested, stained
with PI and FITC-conjugated annexin V, and analyzed by flow cytometry.
To confirm the results obtained from the annexin V staining experiment, human MDA-MB-231
breast cancer cells were also treated with ipomoeassin F, followed by a DNA fragmentation assay. DNA
fragmentation is an indicator of late apoptosis. Consistent with the flow cytometry results, it is clear that
the treatment of MDA-MB-231 cells with ipomoeassin F (lane 3, Figure 5) at the concentration of IC90
(100 nM) resulted in smaller DNA fragments that were also present for the positive control (lane 4,
staurosporine, Figure 5), but not in non-treated cells (lane 2, Figure 5).
1 2 3 4
Figure 5. Ipomoeassin F induces DNA
fragmentation in MDA-MB-231 cells. Lane
1: marker; lane 2: non-treated; lane 3: 100 nM
ipomoeassin F; lane 4: 750 nM staurosporine
(positive control).
CONCLUSIONS
In conclusion, by meticulous examination of subtle reactivity differences among various
hydroxyl groups and careful selection of protecting groups, we introduced the peripheral ester
functional groups to the disaccharide core in such a desired sequence that a much more efficient
total synthesis of ipomoeassin F (3.8% overall yield for 17 linear steps) from commercially-
available starting materials was accomplished. In our route, three highly regioselective reactions
were developed: a) selective allyloxycarbonylation of the 2-OH-Glcp in diol 18; b) selective
silylation of the 3-OH-Fucp in triol 23a/b; and c) selective glycosylation of 2-OH-Fucp in diol
6a/b. To our delight, all of them were accomplished in good to excellent yield. The synthesis can
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 14 of 38
1
2
3
4
5
6
7
8
9
be easily scaled up to gram-scale. This new route secured a meaningful material supply and
enabled several biological assessments for this scarce natural resin glycoside. Using the same
synthetic strategy, the 11R-epimer of ipomoeassin F was prepared for the first time. The
cytotoxicity screens of both compounds undoubtedly demonstrate that the 11S configuration is
crucial for the cytotoxicity of ipomoeassin F. For the first time, we also confirmed that in human
cells, ipomoeassin F can arrest cell cycle in the G1 phase and induce remarkable apoptosis.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
EXPERIMENTAL SECTION
General Methods
Reactions were carried out in oven-dried glassware. All reagents were purchased from
commercial sources and were used without further purification unless noted. Unless stated
otherwise, all reactions were carried out under a nitrogen atmosphere and monitored by TLC
using Silica Gel GF254 plates with detection by charring with 5% (v/v) H2SO4 in EtOH or by
visualizing in UV light (254 nm). Column chromatography was performed on silica gel (230–
1
450 mesh). The ratio between silica gel and crude product ranged from 100 to 50:1 (w/w). H
NMR spectra were obtained in deuteriochloroform (CDCl3) with chloroform (CHCl3, δ = 7.27
1
13
for H) as an internal reference. C NMR spectra were proton decoupled and were in CDCl3
13
with CHCl3 (δ = 77.0 for C) as an internal reference. Chemical shifts are reported in ppm (δ).
Data are presented in the form: chemical shift (multiplicity, coupling constants, and integration).
1H data are reported as though they were first order. The errors between the coupling constants
for two coupled protons were less than 0.5 Hz, and the average number was reported. Proton
assignments, when made, were done so with the aid of COSY NMR spectra. For some
compounds, HSQC and HMBC NMR were also applied to assign the proton signals. Optical
rotations were measured at 25 ± 1 oC for solutions in a 1.0 dm cell. IR spectra were recorded on
an FT-IR spectrometer. HRMS were obtained by electrospray ionization (ESI, FTMS) technique
in positive or negative mode (as indicated).. The purity (>95%) of the obtained ipomoeassin F
and its 11R-epimer was determined by HPLC analysis equipped with a C18 column (150 mm ×
4.6 mm, 5 µm) measured at 280 nm. The mobile phase was a MeCN/H2O mixture. The tested
compounds were at least 95% pure.
Chemistry: Synthetic Procedures and Analytical Data
ACS Paragon Plus Environment

Page 15 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
p-Methoxyphenyl 3-O-tigloyl-4,6-O-isopropylidene-β-D-glucopyranoside (14). Compound
13 was synthesized from penta-O-acetyl-β-D-glucopyranose (11) through three steps with an
overall yield of 49% following the procedure reported in literature.21 DCC (850 mg, 4.12 mmol)
was added in one portion to a cold (0ºC) solution of compound 13 (1120 mg, 3.43 mmol), tiglic
acid (412 mg, 4.12 mmol) and 4-dimethylaminopyridine (41.9 mg, 0.343 mmol) in CH2Cl2 (50
mL). The reaction was allowed to warm to ambient temperature and stirred overnight. At this
point, TLC (silica, 1:2 EtOAc–hexanes) showed the reaction was complete. The precipitate
formed was filtered thru a pad of Celite using CH2Cl2 (10 mL) as the eluent and the filtrate was
concentrated in vacuo. The residue was purified by column chromatography (silica, EtOAc–
hexanes, 1:6 → 1:1) gave 14 (298 mg, 21%), 15 (720 mg, 51%) and 16 (410 mg, 24%) as white
amorphous solids.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Compound 14: [α]D25 –64.1 (c 1 CHCl3). 1H NMR (400 MHz, CDCl3) δ 7.03 – 6.97 (m, 2H, 2
× ArH), 6.98 – 6.91 (m, 1H, Me-CH-C(Me)-C=O), 6.85 – 6.80 (m, 2H, 2 × ArH), 5.12 (t, J = 9.6
Hz, 1H, H-3), 4.93 (d, J = 7.6 Hz, 1H, H-1), 3.98 (dd, J = 10.8, 5.2 Hz, 1H, H-6), 3.85 – 3.75 (m,
6H, H-2, H-4, H-6, -OCH3), 3.48 – 3.41 (m, 1H, H-5), 3.21 (d, J = 3.6 Hz, 1H, OH), 1.90 – 1.80
13
(m, 6H, CH3-CH-C(CH3)-C=O), 1.48 (s, 3H, (CH3)2C), 1.39 (s, 3H, (CH3)2C). C NMR (100
MHz, CDCl3) δ 168.6, 155.6, 150.9, 138.7, 128.1, 118.68 (x2), 114.52 (x2), 102.9, 99.7, 74.8,
73.6, 71.1, 67.4, 62.1, 55.6, 28.9, 18.9, 14.5, 12.1.
25
1
Compound 15: [α]D –57.3 (c 1 CHCl3). H NMR (400 MHz, CDCl3) δ 6.99 – 6.89 (m, 3H,
Me-CH-C(Me)-C=O, 2 × ArH), 6.84 – 6.77 (m, 2H, 2 × ArH), 5.15 (dd, J = 9.2, 8.0 Hz, 1H, H-
2), 4.99 (d, J = 7.6 Hz, 1H, H-1), 3.99 (dd, J = 10.8, 5.6 Hz, 1H, H-6), 3.90 – 3.80 (m, 2H, H-3,
H-6), 3.78 – 3.72 (m, 4H, H-4, -OCH3), 3.43 – 3.35 (m, 1H, H-5), 2.89 (br, 1H, OH), 1.90 –
13
1.78 (m, 6H, CH3-CH-C(CH3)-C=O), 1.55 (s, 3H, (CH3)2C), 1.46 (s, 3H, (CH3)2C). C NMR
(100 MHz, CDCl3) δ 167.7, 155.6, 151.1, 138.9, 127.9, 118.72 (x2), 114.48 (x2), 101.1, 99.9,
74.8, 73.5, 73.0, 67.2, 61.9, 55.6, 28.9, 19.0, 14.5, 12.2.
Compound 16: [α]D25 +8.2 (c 1 CHCl3). 1H NMR (400 MHz, CDCl3) δ 6.96 – 6.88 (m, 2H, 2
× ArH), 6.86 – 6.76 (m, 4H, 2 × ArH, 2 × Me-CH-C(Me)-C=O), 5.38 – 5.27 (m, 2H, H-2, H-3),
5.10 – 5.00 (d, J = 7.2 Hz, 1H, H-1), 4.00 (dd, J = 11.2, 5.6 Hz, 1H, H-6), 3.94 – 3.80 (m, 2H, H-
4, H-6), 3.76 (s, 3H, -OCH3), 3.54 – 3.46 (m, 1H, H-5), 1.82 – 1.73 (m, 12H, 2 × CH3-CH-
C(CH3)-C=O), 1.49 (s, 3H, (CH3)2C), 1.39 (s, 3H, (CH3)2C). 13C NMR (100 MHz, CDCl3) δ
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 16 of 38
1
2
3
4
5
6
7
8
9
167.1, 166.5, 155.6, 151.1, 138.3, 138.0, 128.0, 127.8, 118.8 (x2), 114.5 (x2), 101.2, 99.7, 72.1,
72.0, 71.4, 67.6, 62.1, 55.6, 28.9, 18.9, 14.4, 14.4, 12.1, 12.1.
p-Methoxyphenyl 4,6-O-isopropylidene-α-D-glucopyranoside (18). To a cold (0 oC) solution
of the penta-O-acetyl-β-D-glucopyranose 11 (70.0 g, 179 mmol) and p-methoxyphenol (33.4 g,
269 mmol) in dry CH2Cl2 (800 mL) was added boron trifluoride diethyl etherate (111 mL, 897
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
o
mmol) in 30 min. Then, the mixture was heated to 35 C and agitated for 4 days, at the end of
which time TLC (EtOAc–hexanes, 1:2) indicated that the reaction was complete. The reaction
mixture was poured into crushed ice, and the excess boron trifluoride diethyl etherate was
neutralized by the careful addition of saturated aqueous NaHCO3 solution. The organic layer was
washed with brine, dried (Na2SO4), and concentrated in vacuo to provide a yellowish syrup. The
syrup was dried under high vacuum for 2 h before dissolved in MeOH (500 mL). Sodium
methoxide (2 g) was added to the reaction mixture and stirred at room temperature for 2 h. The
residue was purified by column chromatography (silica, EtOAc–MeOH, 1:20 → 1:5) to afford p-
methoxyphenyl α-D-glucopyranoside 1723 (30.8 g, 60% over 2 steps) as a white solid. To a
solution of compound 17 (28.8 g, 101 mmol) in DMF (200 mL) containing TsOH·H2O (0.38 g,
2.0 mmol) was added 2-methoxypropene (11.6 mL, 121 mmol) under nitrogen atmosphere. The
resulting mixture was stirred for 6 h at room temperature until completion (EtOAc–hexanes, 2:1).
The reaction was quenched with Et3N (0.5 mL) and then diluted with EtOAc (400 mL), washed
with water (400 mL × 3), brine (100 mL). The aqueous layer was extracted with EtOAc (400 mL
× 2). The combined organic layer was dried over Na2SO4 and concentrated under reduced
pressure. The residue was purified by column chromatography (silica, EtOAc–hexanes, 1:1 →
2:1) gave compound 18 (30.2 g, 92%) as a white foam. [α]D25 +124.7 (c 1 CHCl3). 1H NMR (400
MHz, CDCl3) δ 7.02 – 6.96 (m, 2H, 2 × ArH), 6.84 – 6.79 (m, 2H, 2 × ArH), 5.41 (d, J = 3.6 Hz,
1H, H-1), 4.00 (td, J = 9.2, 2.0 Hz, 1H), 3.88 – 3.66 (m, 7H, H-2, H-5, 2 × H-6, -OCH3), 3.61 (t,
J = 8.8 Hz, 1H), 3.45 – 3.40 (m, 1H, OH), 3.00 – 2.92 (m, 1H, OH), 1.52 (s, 3H, (CH3)2C), 1.44
(s, 3H, (CH3)2C). 13C NMR (100 MHz, CDCl3) δ 155.4, 150.2, 118.4 (x2), 114.6 (x2), 99.8, 98.6,
73.4, 72.8, 71.9, 64.0, 62.1, 55.6, 29.0, 19.1. IR (film): ν = 3397, 2994, 2938, 1654, 1508, 1504,
1206, 1043, 847. HRMS (ESI) m/z calcd for C16H22NaO7 [M+Na]+ 349.1263. Found: 349.1260.
p-Methoxyphenyl 2-O-allyloxycarbonyl-4,6-O-isopropylidene-α-D-glucopyranoside (19).
Compound 18 (20.4 g, 62.5 mmol) was dissolved in CH2Cl2 (300 mL) containing pyridine (20
mL, 250 mmol) and DMAP (0.76 g, 6.3 mmol), then under an N2 atmosphere, allyl
ACS Paragon Plus Environment

Page 17 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
chloroformate (7.3 mL68.8 mmol) in CH2Cl2 (50 mL) was added drop wise to the solution at –
35 °C in 30 min. Then the reaction mixture was allowed to gradually warm to 0 °C in 30 min, at
the end of which time TLC (silica, 1: 2 EtOAc–hexanes) showed it was complete. Then the
reaction mixture was quenched with MeOH (0.5 mL) and washed with 1M HCl (200 mL),
saturated aqueous NaHCO3 (100 mL) and brine (100 mL). The aqueous layer was extracted with
CH2Cl2 (200 mL). The combined organic layer was dried over Na2SO4 and concentrated under
reduced pressure. The residue was purified by column chromatography (silica, EtOAc–hexanes,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
25
1
1:4 → 1:3) gave compound 19 (22.1 g, 86%) as a white foam. [α]D +153.2 (c 1 CHCl3). H
NMR (400 MHz, CDCl3) δ 7.01 – 6.94 (m, 2H, 2 × ArH), 6.85 – 6.77 (m, 2H, 2 × ArH), 5.96 –
5.85 (m, 1H, CH2=CH-CH2-), 5.65 (d, J = 3.6 Hz, 1H, H-1), 5.38 – 5.22 (m, 2H, CH2=CH-CH2-),
4.72 (dd, J = 9.6, 3.6 Hz, 1H, H-2), 4.66 – 4.59 (m, 2H, CH2=CH-CH2-), 4.26 (t, J = 9.2 Hz, 1H,
H-3), 3.92 – 3.81 (m, 2H, H-5, H-6), 3.81 – 3.74 (m, 4H, H-6, -OCH3), 3.75 – 3.64 (m, 1H, H-4),
3.04 (br, 1H, OH), 1.54 (s, 3H, (CH3)2C), 1.45 (s, 3H, (CH3)2C). 13C NMR (100 MHz, CDCl3) δ
155.3, 154.4, 150.3, 131.1, 119.2, 118.2 (x2), 114.5 (x2), 100.0, 95.8, 76.7, 73.7, 68.97, 68.8,
63.7, 62.1, 55.6, 28.9, 19.1. IR (film): ν = 3462, 2994, 2941, 1744, 1508, 1205, 1024. HRMS
(ESI) m/z calcd for C20H26NaO9 [M+Na]+ 433.1475. Found: 433.1466.
p-Methoxyphenyl
2-O-allyloxycarbonyl-3-O-tigloyl-4,6-O-isopropylidene-α-D-
glucopyranoside (20). DCC (8.60 g, 41.7 mmol) was added in one portion to a 0ºC CH2Cl2 (100
mL) solution of 19 (11.4 g, 27.8 mmol), tiglic acid (4.17 g, 41.7 mmol) and 4-
dimethylaminopyridine (0.34 g, 2.78 mmol). The reaction was allowed to warm to ambient
temperature and stirred overnight. At this point, TLC (silica, 1:2 EtOAc–hexanes) showed the
reaction was complete. The reaction mixture was diluted with ether (100 mL) and hexanes (50
mL), stirred for 20 minutes then filtered thru a pad of Celite using ether (50 mL) as the eluent
and the filtrate was concentrated in vacuo. The residue was purified by column chromatography
(silica, EtOAc–hexanes, 1:6 → 1:5) gave 20 (13.1 g, 95%) as a colorless syrup. [α]D25 +127.9 (c
1 CHCl3). 1H NMR (400 MHz, MeOD) δ 7.05 – 6.99 (m, 2H, 2 × ArH), 6.93 – 6.83 (m, 3H, Me-
CH-C(Me)-C=O, 2 × ArH), 5.94 – 5.75 (m, 1H, CH2=CH-CH2-), 5.67 (d, J = 3.6 Hz, 1H, H-1),
5.57 (t, J = 10.0 Hz, 1H, H-3), 5.29 – 5.15 (m, 2H, CH2=CH-CH2-), 4.97 (dd, J = 10.0, 3.6 Hz,
1H, H-4), 4.65 – 4.51 (m, 2H, CH2=CH-CH2-), 4.01 – 3.79 (m, 4H, H-4, H-5, 2 × H-6), 3.75 (s,
3H, -OCH3), 3.75 (d, J = 4.7 Hz, 3H), 1.86 – 1.78 (m, 6H, CH3-CH-C(CH3)-C=O), 1.50 (s, 3H,
(CH3)2C), 1.34 (s, 3H, (CH3)2C). 13C NMR (100 MHz, MeOD) δ 168.4, 157.0, 155.6, 151.7,
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 18 of 38
1
2
3
4
5
6
7
8
9
139.6, 132.8, 129.2, 119.4 (x2), 118.9, 115.7 (x2), 101.2, 97.7, 75.9, 73.1, 70.8, 69.8, 65.7, 63.1,
56.0, 29.3, 19.4, 14.5, 12.2. IR (film): ν = 2994, 2940, 1747, 1718, 1653, 1510, 1277, 1247, 1211,
1042. HRMS (ESI) m/z calcd for C25H32NaO10 [M+Na]+ 515.1893, found: 515.1891.
2-O-Allyloxycarbonyl-3-O-tigloyl-4,6-O-isopropylidene-α-D-glucopyranosyl
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
trichloroacetimidate (3). To a solution of compound 20 (10.9 g, 22.1 mmol) in acetonitrile (120
mL) and water (30 mL) was added a solution of CAN (24.3 g, 44.3 mmol) in water (30 mL) in 5
o
min at –10 C. The mixture was stirred for 15 min at the same temperature, at the end of which
time TLC (silica, 1:2 EtOAc–hexanes) indicated that the reaction was complete. The reaction
was quenched with saturated aqueous NaHCO3 and extracted with EtOAc (400 mL × 2). The
combined organic phase was dried over Na2SO4 and concentrated. The obtained residue was
purified by column chromatography (silica, EtOAc–hexanes, 1:4 → 1:2) to afford the desired
hemiacetal. To a solution of the obtained hemiacetal in CH2Cl2 (100 mL) was added
trichloroacetonitrile (8.9 mL, 88 mmol), and DBU (0.33 mL, 2.2 mmol). The mixture was stirred
overnight at room temperature and then was concentrated. The residue was purified by column
chromatography (silica, EtOAc–hexanes, 1:5 → 1:3) to afford the glucosyl donor 3 (6.93 g, 59%
over 2 steps) as a colorless syrup. [α]D25 +59.6 (c 1 CHCl3). 1H NMR (400 MHz, CDCl3) δ 8.65
(s, 1H, CNHCCl3), 6.90 – 6.83 (m, 1H, Me-CH-C(Me)-C=O), 6.57 (d, J = 4.0 Hz, 1H, H-1), 5.93
– 5.76 (m, 1H, CH2=CH-CH2-), 5.61 (t, J = 9.6 Hz, 1H, H-3), 5.36 – 5.17 (m, 2H, CH2=CH-
CH2-), 5.03 (dd, J = 9.6, 4.0 Hz, 1H, H-2), 4.65 – 4.54 (m, 2H, CH2=CH-CH2-), 4.05 – 3.72 (m,
4H, H-2, H-4, H-5, 2 × H-6), 1.90 – 1.76 (m, 6H, CH3-CH-C(CH3)-C=O), 1.49 (s, 3H, (CH3)2C),
13
1.41 (s, 3H, (CH3)2C). C NMR (100 MHz, CDCl3) δ 166.6, 161.2, 154.2, 138.0, 131.1, 128.0,
118.8, 100.0, 93.6, 74.0, 71.7, 69.07, 68.97, 66.2, 62.0, 28.8, 18.9, 14.4, 12.1.
1-Nonen-4S/R-yl 2,3,4-tri-O-acetyl-β-D-fucopyranoside (22a/b). Fucosyl donor 418 was
synthesized from tetra-O-acetyl-D-fucopyranose through two steps with an overall yield of 77%
following the procedure reported in literature. (S)-4-hydroxy-1-nonene (5a)11 and (R)-4-hydroxy-
1-nonene (5b)30 was synthesized from (S)-(+)-Epichlorohydrin and (R)-(-)-Epichlorohydrin
through three steps with an overall yield of 68%, 58%, respectively.
Compound 22a: A mixture of acceptor 5a (3.21 g, 22.5 mmol), donor 4 (9.80 g, 22.5 mmol),
and 4 Å molecular sieves (5 g) in anhydrous, redistilled CH2Cl2 (200 mL) was stirred under an
N2 atmosphere for 30 min and then cooled to –10 oC. TMSOTf (408 µL, 2.3 mmol) was added to
the mixture. Then the reaction mixture was allowed to gradually warm to ambient temperature
ACS Paragon Plus Environment

Page 19 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
with the cold bath in place and was stirred for 1 h. TLC (silica, 1:3 EtOAc–hexanes) indicated
that the reaction was complete. Then the reaction mixture was quenched with Et3N (320 µL) and
filtrated. The filtrate was evaporated in vacuo to give a residue, which was purified by silica gel
column chromatography (silica, EtOAc–hexanes, 1:7 → 1:5) to give compound 22a (8.68 g,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
25
1
93%) as a yellowish syrup. [α]D –9.9 (c 1 CHCl3). H NMR (400 MHz, CDCl3) δ 5.81 – 5.71
(m, 1H, CH2=CH-CH2-), 5.23 – 5.11 (m, 2H, H-4-Fucp, H-2-Fucp), 5.09 – 4.94 (m, 3H, H-3-
Fucp, CH2=CH-CH2-), 4.47 (d, J = 7.6 Hz, 1H, H-1-Fucp), 3.80 – 3.73 (m, 1H, H-5-Fucp), 3.65
– 3.58 (m, 1H, -CH2-CH-CH2-), 2.25 – 2.20 (m, 2H), 2.16 (s, 3H, CH3-C=O), 2.02 (s, 3H, CH3-
C=O), 1.98 (s, 3H, CH3-C=O), 1.62 – 1.44 (m, 2H), 1.38 – 1.21 (m, 6H), 1.20 (d, J = 6.4 Hz, 3H,
13
H-6-Fucp), 0.88 (t, J = 6.8 Hz, 3H). C NMR (100 MHz, CDCl3) δ 170.8, 170.3, 169.4, 134.4,
117.0, 100.5, 80.2, 71.5, 70.3, 69.3, 68.9, 38.4, 34.4, 31.7, 24.6, 22.5, 20.9, 20.7, 20.6, 16.1, 14.0.
The 1H, 13C NMR data were in accordance with the literature.10
Compound 22b: Compound 22b (2.80 g, 74%) was prepared by coupling of acceptor 5b (1.32
g, 9.3 mmol) with donor 4 (4.28 g, 9.8 mmol) under the same conditions as described for the
synthesis of 22a by coupling of 5a with 4. [α]D25 +9.7 (c 1 CHCl3). 1H NMR (400 MHz, CDCl3)
δ 5.88 – 5.75 (m, 1H, CH2=CH-CH2-), 5.25 – 5.13 (m, 2H, H-4-Fucp, H-2-Fucp), 5.09 – 4.96 (m,
3H, H-3-Fucp, CH2=CH-CH2-), 4.49 (d, J = 7.6 Hz, 1H, H-1-Fucp), 3.84 – 3.74 (m, 1H, H-5-
Fucp), 3.65 – 3.56 (m, 1H, -CH2-CH-CH2-), 2.51 – 2.27 (m, 2H), 2.18 (s, 3H, CH3-C=O), 2.04 (s,
3H, CH3-C=O), 1.99 (s, 3H, CH3-C=O), 1.50 – 1.40 (m, 2H), 1.40 – 1.23 (m, 6H), 1.24 (d, J =
13
6.4 Hz, 3H, H-6-Fucp), 0.89 (t, J = 6.8 Hz, 3H). C NMR (100 MHz, CDCl3) δ 170.8, 170.3,
169.4, 134.7, 116.9, 101.2, 81.0, 71.5, 70.3, 69.3, 69.0, 39.7, 33.5, 31.9, 24.7, 22.6, 20.8, 20.7,
20.7, 16.1, 14.0. IR (film): ν = 2936, 2856, 1755, 1600, 1368, 1254, 1229, 1078. HRMS (ESI)
m/z calcd for C21H34NaO8 [M+Na]+ 437.2151, found: 437.2148.
1-Nonen-4S-yl β-D-fucopyranoside (23a). MeONa (224 mg, 4.15 mmol) was added in one
portion to a solution of 22a (8.60 g, 20.7 mmol) in MeOH (200 mL) at room temperature. The
reaction mixture was stirred at room temperature overnight. TLC (silica, 3:1 EtOAc–hexanes)
showed the reaction was complete. Neutralization of the reaction mixture with acidic ion
exchange resin (Amberlite IR-120 (H+), Alfa Aesar) and the organic phase was concentrated in
vacuo. The residue was purified by column chromatography (silica, EtOAc–hexanes, 3:1 → 5:1)
gave triol 23a (5.05 g, 84%) as a colorless syrup. [α]D25 –21.2 (c 1 CHCl3). 1H NMR (400 MHz,
CDCl3) δ 5.91 – 5.78 (m, 1H, CH2=CH-CH2-), 5.20 – 5.02 (m, 2H, CH2=CH-CH2-), 4.24 (d, J =
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 20 of 38
1
2
3
4
5
6
7
8
9
7.6 Hz, 1H, H-1-Fucp), 3.74 – 3.53 (m, 5H, H-2-Fucp, H-3-Fucp, H-4-Fucp, H-5-Fucp, -CH2-
CH-CH2-), 3.36 (d, J = 4.8 Hz, 1H, OH), 2.97 (br, 1H, OH), 2.73 (d, J = 5.6 Hz, 1H, OH), 2.40 –
2.22 (m, 2H), 1.67 – 1.48 (m, 2H), 1.42 – 1.21 (m, 9H), 0.89 (d, J = 6.8 Hz, 3H, H-6-Fucp). 13C
NMR (100 MHz, CDCl3) δ 135.0, 117.5, 102.3, 79.2, 73.9, 72.1, 71.6, 70.5, 38.6, 34.7, 31.8,
24.8, 22.6, 16.3, 14.1. The 1H, 13C NMR data were in accordance with the literature.10
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
1-Nonen-4R-yl β-D-fucopyranoside (23b). Compound 23b (1.37 g, 73%, colorless syrup) was
prepared by treating 22b (2.69 g, 6.49 mmol) with MeONa (80 mg, 1.48 mmol) under the same
25
1
conditions as described for the synthesis of 23a. [α]D +2.0 (c 1 CHCl3). H NMR (400 MHz,
CDCl3) δ 5.91 – 5.78 (m, 1H, CH2=CH-CH2-), 5.11 – 4.99 (m, 2H, CH2=CH-CH2-), 4.25 (d, J =
7.6 Hz, 1H, H-1-Fucp), 3.76 – 3.54 (m, 5H, H-2-Fucp, H-3-Fucp, H-4-Fucp, H-5-Fucp, -CH2-
CH-CH2-), 3.90 (br 1H, OH), 3.41 (br, 1H, OH), 3.24 (br, 1H, OH), 2.46 – 2.30 (m, 2H), 1.57 –
13
1.48 (m, 2H), 1.45 – 1.21 (m, 9H), 0.89 (d, J = 6.8 Hz, 3H, H-6-Fucp). C NMR (100 MHz,
CDCl3) δ 135.0, 116.8, 102.6, 79.7, 73.9, 71.7, 71.6, 70.5, 39.6, 33.5, 31.9, 24.8, 22.6, 16.4, 14.0.
IR (film): ν = 3381, 2928, 2859, 1639, 1070, 995, 912, 756. HRMS (ESI) m/z calcd for
C15H28NaO5 [M+Na]+ 311.1834, found: 311.1830.
o
1-Nonen-4S-yl 3-O-tert-butyldimethylsilyl-β-D-fucopyranoside (6a). To a cold (0 C)
solution of triol 23a (5.05 g, 17.5 mmol) and 1H-Imidazole (3.58 g, 52.5 mmol) in DMF (100
mL) was added t-butyldimethylsilyl chloride (3.70 g, 24.5 mmol). The reaction was stirred at 0
oC for 30 min and then was allowed to warm to ambient temperature and stirred for a further 2 h.
At this point, TLC (silica, 1:9 EtOAc–hexanes) showed the reaction was complete. The reaction
mixture was diluted with ether (500 mL), washed with water (3 × 150 mL) and brine (100 mL).
The aqueous layer was extracted with ether (200 mL). The combined organic layer was dried
over Na2SO4, filtered and concentrated. The residue was purified by column chromatography
(silica, EtOAc–hexanes, 1:30 → 1:20) to afford compound 6a (5.05 g, 72%) as a colorless syrup.
25
1
[α]D –6.9 (c 1 CHCl3). H NMR (400 MHz, CDCl3) δ 5.91 – 5.74 (m, 1H, CH2=CH-CH2-),
5.14 – 4.98 (m, 2H, CH2=CH-CH2-), 4.20 (d, J = 7.8 Hz, 1H, H-1-Fucp), 3.73 – 3.65 (m, 1H, -
CH2-CH-CH2-), 3.63 (dd, J = 9.2, 3.6 Hz, 1H, H-3-Fucp), 3.59 – 3.48 (m, 3H, H-2-Fucp, H-4-
Fucp, H-5-Fucp), 2.62 (br, 1H, OH), 2.38 – 2.21 (m, 2H), 2.17 (d, J = 1.6 Hz, 1H, OH), 1.67 –
1.47 (m, 2H), 1.39 – 1.22 (m, 9H), 0.96 – 0.84 (m, 12H), 0.15 (s, 3H, CH3-Si), 0.13 (s, 3H, CH3-
13
Si). C NMR (100 MHz, CDCl3) δ 135.1, 117.4, 102.2, 78.9, 74.9, 72.1, 72.1, 70.0, 38.5, 34.7,
31.8, 25.8(3), 24.7, 22.6, 18.1, 16.4, 14.1, –4.4, –5.0. IR (film): ν = 3537, 2930, 2857, 1655,
ACS Paragon Plus Environment

Page 21 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
1109, 1066, 997, 910, 839, 781. HRMS (ESI) m/z calcd for C21H42NaO5Si [M+Na]+ 425.2699,
found: 425.2696.
7
8
9
1-Nonen-4R-yl 3-O-tert-butyldimethylsilyl-β-D-fucopyranoside (6b). Compound 6b (0.36 g,
71%, colorless syrup) was prepared by treating 23b (0.36 g, 1.2 mmol) with 1H-Imidazole (0.24
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
25
g, 3.5 mmol) under the same conditions as described for the synthesis of 6a. [α]D +7.8 (c 1
CHCl3). 1H NMR (400 MHz, CDCl3) δ 5.91 – 5.74 (m, 1H, CH2=CH-CH2-), 5.14 – 4.98 (m, 2H,
CH2=CH-CH2-), 4.20 (d, J = 7.8 Hz, 1H, H-1-Fucp), 3.73 – 3.65 (m, 1H, -CH2-CH-CH2-), 3.63
(dd, J = 9.2, 3.6 Hz, 1H, H-3-Fucp), 3.59 – 3.48 (m, 3H, H-2-Fucp, H-4-Fucp, H-5-Fucp), 2.62
(br, 1H, OH), 2.38 – 2.21 (m, 2H), 2.17 (d, J = 1.6 Hz, 1H, OH), 1.67 – 1.47 (m, 2H), 1.39 –
13
1.22 (m, 9H), 0.96 – 0.84 (m, 12H), 0.15 (s, 3H, CH3-Si), 0.13 (s, 3H, CH3-Si). C NMR (100
MHz, CDCl3) δ 135.1, 117.4, 102.2, 78.9, 74.9, 72.1, 72.1, 70.0, 38.5, 34.7, 31.8, 25.8 (x3), 24.7,
22.6, 18.1, 16.4, 14.1, –4.4, –5.0. IR (film): ν = 3379, 2930, 2856, 1653, 1074, 997, 800, 760.
HRMS (ESI) m/z calcd for C21H42NaO5Si [M+Na]+ 425.2699, found: 425.2693.
1-Nonen-4S-yl 2,4-di-O-acetyl-3-O-tert-butyldimethylsilyl-β-D-fucopyranoside (24). To a
solution of compound 6a (10 mg, 0.025 mmol) and DMAP (1 mg) in pyridine (1 mL) was added
acetic anhydride (100 µL). The reaction mixture was stirred at room temperature overnight, at
the end of which time TLC (silica, 1:6 EtOAc–hexanes) indicated that the reaction was complete.
The mixture was concentrated under diminished pressure and then co-evaporated with toluene (2
× 3 mL) gave the crude product. The residue was purified by column chromatography (silica,
EtOAc–hexanes, 1:10) to afford compound 24 (11 mg, 92%) as a colorless syrup. [α]D25 –1.1 (c 1
CHCl3). 1H NMR (400 MHz, CDCl3) δ 5.84 – 5.69 (m, 1H, CH2=CH-CH2-), 5.11 – 4.99 (m, 4H,
CH2=CH-CH2-, H-2-Fucp, H-4-Fucp), 4.36 (d, J = 8.0 Hz, 1H, H-1-Fucp), 3.78 (dd, J = 9.6, 3.6
Hz, 1H, H-3-Fucp), 3.70 – 3.63 (m, 1H, H-5-Fucp), 3.62 – 3.55 (m, 1H, -CH2-CH-CH2-), 2.28 –
2.18 (m, 2H), 2.15 (s, 3H, CH3-C=O), 2.05 (s, 3H, CH3-C=O), 1.65 – 1.21 (m, 8H), 1.18 (d, J =
6.4 Hz, 3H, H-6-Fucp), 0.88 (t, J = 6.8 Hz, 3H), 0.83 (s, 9H), 0.07 (s, 3H, CH3-Si), 0.06 (s, 3H,
CH3-Si). 13C NMR (100 MHz, CDCl3) δ 170.9, 169.2, 134.7, 116.9, 100.6, 79.9, 72.9, 72.3, 71.5,
69.0, 38.4, 34.4, 31.8, 25.4 (x3), 24.7, 22.6, 21.3, 20.9, 17.8, 16.3, 14.1, –4.8, –5.1. IR (film): ν =
2928, 2855, 1744, 1371, 1231, 1119, 1063, 837, 781.
Disaccharide 25a. A mixture of acceptor 6a (4.30 g, 10.7 mmol), donor 3 (6.24 g, 11.7 mmol),
and 4 Å molecular sieves (5 g) in anhydrous, redistilled CH2Cl2 (300 mL) was stirred under an
N2 atmosphere for 30 min and then cooled to –60 oC. TMSOTf (193 µL, 1.07 mmol) was added
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 22 of 38
1
2
3
4
5
6
7
8
9
o
to the mixture. Then the reaction mixture was allowed to gradually warm to –20 C over 2 h, at
the end of which time TLC (silica, 1:6 EtOAc–hexanes) showed it was complete. Then the
reaction mixture was quenched with Et3N (150 µL) and filtrated. The filtrate was evaporated in
vacuo to give a residue, which was purified by silica gel column chromatography (silica, EtOAc–
hexanes, 1:20 → 1:10) to give compound 25a (7.62 g, 93%) as a colorless syrup. [α]D25 –17.2 (c
1 CHCl3). 1H NMR (400 MHz, CDCl3) δ 6.86 – 6.81 (m, 1H, Me-CH=C(Me)-C=O), 6.05 – 5.92
(m, 1H, CH2=CH-CH2-), 5.90 – 5.78 (m, 1H, CH2=CH-CH2-), 5.33 – 5.00 (m, 6H, 2 × CH2=CH-
CH2-, H-3-Glup, H-1-Glup), 4.71 (dd, J = 9.6, 8.0 Hz, 1H, H-2-Glup), 4.65 – 4.45 (m, 2H,
CH2=CH-CH2-O-), 4.29 (d, J = 7.6 Hz, 1H, H-1-Fucp), 3.97(dd, J = 11.2, 5.6 Hz, 1H, H-6-Glup),
3.85 – 3.68 (m, 4H, H-2-Fucp, H-3-Fucp, H-4-Glup, H-6-Glup), 3.68 – 3.59 (m, 1H), 3.55 – 3.45
(m, 2H), 3.30 (m, 1H, H-5-Glup), 2.38 (br, 1H, OH), 2.29 (t, J = 6.8 Hz, 2H), 1.87 – 1.72 (m, 6H,
CH3-CH-C(CH3)-C=O), 1.56 – 1.47 (m, 2H), 1.45 (s, 3H), 1.42 – 1.18 (m, 12H), 1.02 – 0.83 (m,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
13
12H), 0.17 (s, 3H, CH3-Si), 0.10 (s, 3H, CH3-Si). C NMR (100 MHz, CDCl3) δ 166.9, 154.2,
137.9, 135.6, 131.4, 128.0, 118.4, 116.3, 100.7, 99.6, 99.6, 79.3, 77.2, 76.1, 75.6, 72.4, 72.3, 71.7,
69.5, 68.4, 67.2, 62.1, 38.3, 34.3, 31.9, 28.9, 25.9 (x3), 24.6, 22.6, 18.8, 18.0, 16.4, 14.4, 14.1,
12.1, –4.6 (x2). IR (film): ν = 3561, 2932, 2859, 1757, 1721, 1655, 1263, 1070, 980, 908, 835,
779. HRMS (ESI) m/z calcd for C39H66NaO13Si [M+Na]+ 793.4170, found: 793.4169.
Disaccharide 25b. 25b (0.51 g, 66%, colorless syrup) was prepared by coupling of acceptor
6b (0.45 g, 1.1 mmol) with donor 3 (0.54 g, 1.0 mmol) under the same conditions as described
25
1
for the synthesis of 25a by coupling of 6a with 3. [α]D –3.9 (c 1 CHCl3). H NMR (400 MHz,
CDCl3) δ 6.89 – 6.79 (m, 1H, Me-CH=C(Me)-C=O), 5.85 – 5.79 (m, 2H, 2 x CH2=CH-CH2-),
5.34 – 4.99 (m, 6H, 2 × CH2=CH-CH2-, H-3-Glup, H-1-Glup), 4.72 (dd, J = 9.6, 8.0 Hz, 1H, H-
2-Glup), 4.62 – 4.49 (m, 2H, CH2=CH-CH2-O-), 4.28 (d, J = 7.6 Hz, 1H, H-1-Fucp), 3.97(dd, J =
11.2, 5.6 Hz, 1H, H-6-Glup), 3.86 – 3.67 (m, 4H, H-2-Fucp, H-3-Fucp, H-4-Glup, H-6-Glup),
3.68 – 3.59 (m, 1H), 3.56 – 3.47 (m, 2H), 3.31 (m, 1H, H-5-Glup), 2.37 (br, 1H, OH), 2.36 (t, J =
6.8 Hz, 2H), 1.83 – 1.75 (m, 6H, CH3-CH-C(CH3)-C=O), 1.55 – 1.46 (m, 2H), 1.46 (s, 3H), 1.41
13
– 1.20 (m, 12H), 1.00 – 0.82 (m, 12H), 0.18 (s, 3H, CH3-Si), 0.11 (s, 3H, CH3-Si). C NMR
(100 MHz, CDCl3) δ 166.9, 154.2, 137.9, 135.2, 131.4, 128.1, 118.3, 116.5, 101.1, 99.6, 99.6,
79.9, 77.2, 75.8, 75.7, 72.4, 72.3, 71.8, 69.5, 68.4, 67.2, 62.2, 39.4, 33.5, 32.3, 28.9, 25.9 (x3),
24.7, 22.9, 18.8, 18.0, 16.5, 14.4, 14.0, 12.1, –4.6 (x2). IR (film): ν = 3356, 2932, 2860, 1759,
ACS Paragon Plus Environment

Page 23 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
1724, 1651, 1269, 1096, 839, 760. HRMS (ESI) m/z calcd for C39H66NaO13Si [M+Na]+ 793.4170,
found: 793.4167.
7
8
9
Disaccharide 7a. To a cold (0 oC) solution of compound 25a (7.60 g, 9.86 mmol) and DMAP
(120 mg, 0.99 mmol) in pyridine (20 mL) was added acetic anhydride (10 mL). The reaction
mixture was heated to 60 oC and stirred for a further 24 h, at the end of which time TLC (silica,
1:6 EtOAc–hexanes) indicated that the reaction was complete. The mixture was concentrated
under diminished pressure and then co-evaporated with toluene (2 × 20 mL) gave the crude
product. The residue was purified by column chromatography (silica, EtOAc–hexanes, 1:20 →
1:10) to afford compound 7a (6.12 g, 76%, 83% based on recovered 25a) as a colorless syrup;
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
1
25
1
recovered 25a (0.60g, 8%, H NMR, 400 MHz). [α]D –11.1 (c 1 CHCl3). H NMR (400 MHz,
CDCl3) δ 6.89 – 6.80 (m, 1H, Me-CH=C(Me)-C=O), 6.10 – 5.96 (m, 1H, CH2=CH-CH2-), 5.89 –
5.73 (m, 1H, CH2=CH-CH2-), 5.35 – 5.03 (m, 6H, 2 × CH2=CH-CH2-, H-3-Glup, H-1-Glup),
5.00 (m, 1H, H-4-Fucp), 4.75 (dd, J = 9.6, 8.0 Hz, 1H, H-2-Glup), 4.62 – 4.46 (m, 2H, CH2=CH-
CH2-O-), 4.31 (d, J = 7.6 Hz, 1H, H-1-Fucp), 4.02 (dd, J = 10.8, 5.2 Hz, 1H, H-6-Glup), 3.90 (dd,
J = 9.2, 8.0 Hz, 1H, H-2-Fucp), 3.82 – 3.70 (m, 3H, H-3-Fucp, H-4-Glup, H-6-Glup), 3.68 – 3.57
(m 2H), 3.33 (m, 1H, H-5-Glup), 2.34 (br, 2H), 2.12 (s, 3H, CH3-C=O), 1.84 – 1.74 (m, 6H,
CH3-CH-C(CH3)-C=O), 1.62 – 1.48 (m, 2H), 1.46 (s, 3H, (CH3)2C), 1.40 – 1.22 (m, 9H), 1.13 (d,
J = 6.4 Hz, 3H, H-6-Fucp), 0.94 – 0.83 (m, 12H), 0.12 (s, 3H, CH3-Si), 0.09 (s, 3H, CH3-Si). 13C
NMR (100 MHz, CDCl3) δ 170.8, 166.8, 154.2, 137.9, 135.6, 131.4, 128.0, 118.3, 116.2, 101.3,
99.6, 99.5, 80.5, 77.1, 75.5, 73.5, 73.4, 72.3, 71.8, 68.9, 68.4, 67.3, 62.2, 38.4, 34.3, 31.8, 28.9,
25.8 (x3), 24.6, 22.6, 20.9, 18.9, 17.7, 16.5, 14.4, 14.1, 12.1, –4.3, –4.9. IR (film): ν = 2932,
2859, 1759, 1744, 1653, 1649, 1253, 1069, 839, 758. HRMS (ESI) m/z calcd for C41H68NaO14Si
[M+Na]+ 835.4276, found: 835.4270.
Disaccharide 7b. Compound 7b (321 mg, 78%, colorless syrup) was prepared by treating 25b
(392 mg, 0.51 mmol) with acetic anhydride (1 mL) and DMAP (6.2 mg, 0.051 mmol) in pyridine
25
(3 mL) under the same conditions as described for the synthesis of 7a. [α]D –0.6 (c 1 CHCl3).
1H NMR (400 MHz, CDCl3) δ 6.89 – 6.80 (m, 1H, Me-CH=C(Me)-C=O), 5.91 – 5.78 (m, 2H, 2
x CH2=CH-CH2-), 5.33 – 5.02 (m, 6H, 2 × CH2=CH-CH2-, H-3-Glup, H-1-Glup), 5.00 (m, 1H,
H-4-Fucp), 4.74 (dd, J = 9.6, 8.0 Hz, 1H, H-2-Glup), 4.62 – 4.47 (m, 2H, CH2=CH-CH2-O-),
4.30 (d, J = 7.6 Hz, 1H, H-1-Fucp), 4.01 (dd, J = 10.8, 5.2 Hz, 1H, H-6-Glup), 3.92 (dd, J = 9.2,
8.0 Hz, 1H, H-2-Fucp), 3.80 – 3.67 (m, 3H, H-3-Fucp, H-4-Glup, H-6-Glup), 3.66 – 3.57 (m 2H),
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 24 of 38
1
2
3
4
5
6
7
8
9
3.31 (m, 1H, H-5-Glup), 2.35 (br, 2H), 2.11 (s, 3H, CH3-C=O), 1.82 – 1.72 (m, 6H, CH3-CH-
C(CH3)-C=O), 1.62 – 1.48 (m, 2H), 1.43 (s, 3H, (CH3)2C), 1.41 – 1.25 (m, 9H), 1.13 (d, J = 6.4
Hz, 3H, H-6-Fucp), 0.98 – 0.82 (m, 12H), 0.12 (s, 3H, CH3-Si), 0.09 (s, 3H, CH3-Si). 13C NMR
(100 MHz, CDCl3) δ 170.8, 166.8, 154.3, 137.9, 135.0, 131.4, 128.0, 118.3, 116.7, 101.6, 99.6,
99.5, 81.0, 77.1, 75.2, 73.5, 73.4, 72.2, 72.0, 68.9, 68.4, 67.2, 62.3, 39.4, 33.7, 32.3, 28.9, 25.8
(x3), 24.9, 22.9, 20.9, 18.8, 17.7, 16.6, 14.4, 14.2, 12.0, –4.2, –5.0. IR (film): ν = 2932, 2859,
1759, 1655, 1269, 1115, 1096, 839, 760. HRMS (ESI) m/z calcd for C41H68NaO14Si [M+Na]+
835.4276, found: 835.4273.
Disaccharide 26a. To a cooled (–10 oC) solution of compound 7a (5.52 g, 6.79 mmol) in 1:1
MeOH–THF (160 mL) was added CH3COONH4 (5.23 g, 67.9 mmol). With vigorous stirring,
NaBH4 (51 mg, 1.4 mmol), Pd[P(C6H5)3]4 (314 mg, 0.27 mmol), and NaBH416,31-33 (462 mg, 12.2
mmol) was added in 3 portions immediately one after another. Four minutes after the addition of
the second portion of NaBH4, TLC (EtOAc–hexanes, 1: 6) indicated that the reaction was
complete. The reaction mixture was concentrated under diminished pressure, the residue was
dissolved in CH2Cl2 (200 mL) and washed with water (100 mL), then the organic layer was dried
over Na2SO4. Evaporation and purification by column chromatography (silica, EtOAc–hexanes,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
25
1
1:10) to afford compound 26a (4.71 g, 95%) as a colorless syrup. [α]D –8.6 (c 1 CHCl3). H
NMR (400 MHz, CDCl3) δ 6.90 – 6.81 (m, 1H, Me-CH=C(Me)-C=O), 5.92 – 5.79 (m, 1H,
CH2=CH-CH2-), 5.16 (t, J = 9.6 Hz, 1H, H-3-Glup), 5.11 – 5.00 (m, 3H, CH2=CH-CH2-, H-4-
Fucp), 4.72 (d, J = 8.0 Hz, 1H, H-1-Glup), 4.39 (d, J = 7.6 Hz, 1H, H-1-Fucp), 3.98 – 3.85 (m,
2H, H-6-Glup, H-2-Fucp), 3.82 – 3.74 (m, 2H, H-6-Glup, H-3-Fucp), 3.73 – 3.65 (m, 2H, H-4-
Glup), 3.64 – 3.56 (m, 1H, H-5-Fucp), 3.55 – 3.46 (m, 2H, H-2-Glup, OH), 3.42 – 3.37 (m, 1H,
H-5-Glup), 2.37 – 2.24 (m, 2H), 2.10 (s, 3H, CH3-C=O), 1.88 – 1.74 (m, 6H, CH3-CH-C(CH3)-
C=O), 1.60 – 1.49 (m, 2H), 1.45 (s, 3H, (CH3)2C), 1.40 – 1.21 (m, 9H), 1.13 (d, J = 6.4 Hz, 3H,
13
H-6-Fucp), 0.91 – 0.83 (m, 12H), 0.17 (s, 3H, CH3-Si), 0.14 (s, 3H, CH3-Si). C NMR (100
MHz, CDCl3) δ 170.8, 167.5, 137.3, 134.6, 128.4, 116.9, 104.6, 101.4, 99.6, 79.1, 79.0, 75.4,
72.8, 72.7, 72.6, 71.6, 68.8, 68.3, 62.2, 38.1, 34.0, 31.8, 28.9, 25.8 (x3), 24.3, 22.6, 20.9, 18.9,
17.8, 16.4, 14.3, 14.0, 12.1, –4.5, –4.6. IR (film): ν = 3447, 2930, 2859, 1744, 1719, 1653, 1252,
1233, 1066, 837, 754. HRMS (ESI) m/z calcd for C37H64NaO12Si [M+Na]+ 751.4065, found:
751.4060.
ACS Paragon Plus Environment

Page 25 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
Disaccharide 26b. Compound 26b (343 mg, 85%, colorless syrup) was prepared by treating
7b (450 mg, 0.55 mmol) with CH3COONH4 (427 mg, 5.53 mmol), Pd[P(C6H5)3]4 (26 mg, 0.02
mmol) and NaBH4 (31 mg, 0.82 mmol) in 1:1 MeOH–THF (15 mL) under the same conditions
25
1
as described for the synthesis of 26a. [α]D –1.5 (c 1 CHCl3). H NMR (400 MHz, CDCl3) δ
6.90 – 6.80 (m, 1H, Me-CH=C(Me)-C=O), 5.93 – 5.79 (m, 1H, CH2=CH-CH2-), 5.15 (t, J = 9.6
Hz, 1H, H-3-Glup), 5.10 – 5.00 (m, 3H, CH2=CH-CH2-, H-4-Fucp), 4.70 (d, J = 8.0 Hz, 1H, H-
1-Glup), 4.39 (d, J = 7.6 Hz, 1H, H-1-Fucp), 3.99 – 3.85 (m, 2H, H-6-Glup, H-2-Fucp), 3.83 –
3.72 (m, 2H, H-6-Glup, H-3-Fucp), 3.72 – 3.69 (m, 2H, H-4-Glup), 3.62 – 3.58 (m, 1H, H-5-
Fucp), 3.57 – 3.43 (m, 2H, H-2-Glup, OH), 3.40 – 3.35 (m, 1H, H-5-Glup), 2.49 – 2.30 (m, 2H),
2.10 (s, 3H, CH3-C=O), 1.90 – 1.73 (m, 6H, CH3-CH-C(CH3)-C=O), 1.60 – 1.50 (m, 2H), 1.46 (s,
3H, (CH3)2C), 1.41 – 1.21 (m, 9H), 1.15 (d, J = 6.4 Hz, 3H, H-6-Fucp), 0.94 – 0.80 (m, 12H),
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
13
0.18 (s, 3H, CH3-Si), 0.15 (s, 3H, CH3-Si). C NMR (75 MHz, CDCl3) δ 170.9, 167.6, 137.4,
134.6, 128.4, 117.0, 104.5, 101.5, 99.6, 79.5, 78.8, 75.4, 72.8, 72.8, 72.7, 71.7, 68.8, 68.3, 62.3,
38.7, 32.9, 32.1, 29.0, 25.8 (x3), 24.7, 22.6, 20.9, 18.9, 17.8, 16.5, 14.4, 14.1, 12.1, –4.5, –4.5.
HRMS (ESI) m/z calcd for C37H64NaO12Si [M+Na]+ 751.4065, found: 751.4058.
Disaccharide 27a. TBSOTf (5.94 mL, 25.8 mmol) was added to a solution of compound 26a
(4.71 g, 6.46 mmol) and 2,6-lutidine (7.48 mL, 64.6 mmol) in distilled CH2Cl2 (100 mL) at 0 oC.
The reaction was allowed to warm to ambient temperature and stirred for 24 h. At this point,
TLC (silica, 1:6 EtOAc–hexanes) showed the reaction was complete. Evaporation of the solvent
followed by purification of the residue by flash chromatography (silica, EtOAc–hexanes, 1:20 →
1:10) gave compound 27a (3.61 g, 66%) as a colorless syrup and 28a (1.45 g, 27 %) as a white
foam.
25
1
27a. [α]D –7.8 (c 1 CHCl3). H NMR (400 MHz, CDCl3) δ 6.88 – 6.75 (m, 1H, Me-
CH=C(Me)-C=O), 6.16 – 5.99 (m, 1H, CH2=CH-CH2-), 5.15 – 5.02 (m, 3H, H-3-Glup,
CH2=CH-CH2-), 4.99 – 4.92 (m, 2H, H-1-Glup, H-4-Fucp), 4.32 (d, J = 7.6 Hz, 1H, H-1-Fucp),
4.03 (dd, J = 9.2, 7.6 Hz, 1H, H-2-Fucp), 3.95 (dd, J = 10.8, 5.2 Hz, 1H, H-6-Glup), 3.85 (dd, J =
9.2, 4.0 Hz, 1H, H-3-Fucp), 3.71 (t, J = 10.4 Hz, 1H, H-6-Glup), 3.67 – 3.58 (m, 2H, H-5-Fucp, -
CH2-CH-CH2-), 3.57 – 3.50 (m, 2H, H-2-Glup, H-4-Glup), 3.30 – 3.21 (m, 1H, H-5-Glup), 2.32
(t, J = 6.4 Hz, 2H), 2.11 (s, 3H, CH3-C=O), 1.82 – 1.75 (m, 6H, CH3-CH-C(CH3)-C=O), 1.66 –
1.45 (m, 2H), 1.41 (s, 3H, (CH3)2C), 1.39 – 1.22 (m, 9H), 1.12 (d, J = 6.4 Hz, 3H, H-6-Fucp),
0.91 – 0.83 (m, 12H), 0.78 (s, 9H), 0.14 (s, 3H, CH3-Si), 0.09 (s, 3H, CH3-Si), 0.08 (s, 3H, CH3-
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 26 of 38
1
2
3
4
5
6
7
8
9
13
Si), –0.01 (s, 3H, CH3-Si). C NMR (100 MHz, CDCl3) δ 170.9, 166.8, 136.9, 135.9, 128.7,
116.1, 101.0, 100.5, 99.3, 80.6, 74.9, 74.3, 74.2, 73.8, 73.3, 72.5, 68.8, 66.9, 62.5, 38.5, 34.3,
31.8, 28.9, 25.8 (x3), 25.8 (x3), 24.5, 22.6, 21.0, 18.8, 18.1, 17.6, 16.7, 14.3, 14.0, 12.1, –3.2, –
4.0, –4.3, –5.3.IR (film): ν = 2930, 2859, 1743, 1728, 1653, 1200, 1066, 835, 777. HRMS (ESI)
m/z calcd for C43H78NaO12Si2 [M+Na]+ 865.4930, found: 865.4929.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
25
1
28a. [α]D –19.3 (c 1 CHCl3). H NMR (400 MHz, CDCl3) δ 6.92 – 6.75 (m, 1H, Me-
CH=C(Me)-C=O), 6.09 – 5.93 (m, 1H, CH2=CH-CH2-), 5.15 – 5.03 (m, 2H, CH2=CH-CH2-),
5.02 (d, J = 7.6 Hz, 1H, H-1-Glup), 4.98 – 4.91 (m, 2H, H-2-Glup, H-4-Fucp), 4.32 (d, J = 7.6
Hz, 1H, H-1-Fucp), 3.95 (dd, J = 10.8, 5.2 Hz, 1H, H-6-Glup), 3.86 (dd, J = 9.2, 7.6 Hz, 1H, H-
2-Fucp), 3.77 (t, J = 10.4 Hz, 1H, H-6-Glup), 3.72 (d, J = 9.6, 3.6 Hz, 1H, H-3-Fucp), 3.72 –
3.63 (m, 2H, H-5-Fucp, -CH2-CH-CH2-), 3.61 – 3.51 (m, 2H, H-3-Glup, H-4-Glup), 3.25 – 3.16
(m, 1H, H-5-Glup), 2.36 (t, J = 6.4 Hz, 2H), 2.09 (s, 3H, CH3-C=O), 1.85 – 1.76 (m, 6H, CH3-
CH-C(CH3)-C=O), 1.61 – 1.50 (m, 2H), 1.47 (s, 3H, (CH3)2C), 1.40 (s, 3H, (CH3)2C), 1.38 –
1.21 (m, 6H), 1.11 (d, J = 6.4 Hz, 3H, H-6-Fucp), 0.88 (t, J = 6.8 Hz, 3H), 0.85 (s, 9H), 0.79 (s,
9H), 0.07 (s, 3H, CH3-Si), 0.05 (s, 3H, CH3-Si), 0.03 (s, 3H, CH3-Si), –0.04 (s, 3H, CH3-Si). 13C
NMR (100 MHz, CDCl3) δ 170.8, 166.0, 137.5, 135.5, 128.6, 116.4, 101.3, 99.7, 99.3, 80.0, 75.7,
75.3, 73.9, 73.8, 73.6, 73.4, 68.8, 67.2, 62.4, 38.3, 34.2, 31.9, 29.0, 25.8 (x3), 25.6 (x3), 24.6,
22.6, 20.9, 18.9, 18.1, 17.8, 16.5, 14.2, 14.1, 12.3, –4.2, –4.5, –4.6, –5.1. IR (film): ν = 2930,
2857, 1744, 1728, 1653, 1246, 1066, 835, 777.
Disaccharide 27b. 27b (298 mg crude product) was prepared by treating 26b (343 mg, 0.47
mmol) with TBSOTf (0.43 mL, 1.9 mmol) and 2,6-lutidine (0.55 mL, 4.7 mmol) in distilled
CH2Cl2 (5 mL) under the same conditions as described for the synthesis of 27a. Attempt to get
pure 27b using column chromatography (silica, EtOAc–hexanes) was not successful. The crude
product was used in the next step to get 29b.
Diol 29a. CSA (199 mg, 0.86mmol) was added in one portion to a solution of 27a (3.61 g, 4.28
mmol) in MeOH (100 mL) at room temperature. The reaction mixture was stirred for 3 h at
which point TLC (silica, 1:3 EtOAc–hexanes) showed it was complete. The reaction was
quenched with Et3N (240 µL, 1.72 mmol) and concentrated. The residue was purified by column
chromatography (silica, EtOAc–hexanes, 1:3 → 1:2) gave compound 29a (3.26 g, 95%) as a
25
1
white foam. [α]D +19.1 (c 1 CHCl3). H NMR (400 MHz, CDCl3) δ 7.00 – 6.85 (m, 1H, Me-
CH=C(Me)-C=O), 6.07 – 5.94 (m, 1H, CH2=CH-CH2-), 5.16 – 5.02 (m, 2H, CH2=CH-CH2-),
ACS Paragon Plus Environment

Page 27 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
5.01 – 4.88 (m, 3H, H-1-Glup, H-3-Glup, H-4-Fucp), 4.31 (d, J = 7.6 Hz, 1H, H-1-Fucp), 4.06 (t,
J = 8.4 Hz, 1H, H-2-Fucp), 3.91 (dd, J = 12.0, 3.6 Hz, 1H, H-6-Glup), 3.85 (dd, J = 9.2, 3.6 Hz,
1H, H-3-Fucp), 3.78 (dd, J = 12.0, 4.4 Hz, 1H, H-6-Glup), 3.70 – 3.59 (m, 3H, H-4-Glup, H-5-
Fucp, -CH2-CH-CH2-), 3.58 – 3.52 (m, 1H, H-2-Glup), 3.41 – 3.33 (m, 1H, H-5-Glup), 235 –
2.29 (m, 4H), 2.14 (s, 3H, CH3-C=O), 1.88 – 1.77 (m, 6H, CH3-CH-C(CH3)-C=O), 1.69 – 1.50
(m, 2H), 1.43 – 1.21 (m, 6H), 1.14 (d, J = 6.4 Hz, 3H, H-6-Fucp), 0.92 – 0.82 (m, 12H), 0.80 (s,
9H), 0.15 (s, 3H, CH3-Si), 0.11 (s, 6H, 2 × CH3-Si), 0.06 (d, J = 11.9 Hz, 3H, CH3-Si). 13C NMR
(100 MHz, CDCl3) δ 170.9, 169.2, 138.7, 135.4, 128.2, 116.5, 101.2, 100.0, 80.7, 79.2, 75.2,
74.4, 73.8, 73.5, 73.3, 70.7, 68.9, 62.2, 38.5, 34.3, 31.8, 25.9 (x3), 25.8 (x3), 24.6, 22.6, 21.1,
18.1, 17.6, 16.7, 14.5, 14.1, 12.1, –3.0, –3.9, –4.2, –5.3. IR (film): ν = 3446, 2930, 2857, 1740,
1718, 1653, 1256, 1076, 839, 762. HRMS (ESI) m/z calcd for C40H74NaO12Si2 [M+Na]+
825.4617, found: 825.4614.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Diol 29b. 27b (298 mg, crude product) was dissolved in a 70% solution of acetic acid and
water (10 mL). The reaction mixture was stirred at 70 oC for 1 h at which point TLC (silica, 1:3
EtOAc–hexanes) showed it was complete. The reaction was concentrated and then coevaporated
with toluene (3 x 5 mL). The residue was purified by column chromatography (silica, EtOAc–
25
hexanes, 1:3 → 1:2) and gave compound 29b (165 mg, 44% over 2 steps) as a white foam. [α]D
1
+15.4 (c 1 CHCl3). H NMR (400 MHz, CDCl3) δ 6.96 – 6.85 (m, 1H, Me-CH=C(Me)-C=O),
5.90 – 5.79 (m, 1H, CH2=CH-CH2-), 5.11 – 5.01 (m, 2H, CH2=CH-CH2-), 5.01 – 4.90 (m, 3H,
H-1-Glup, H-3-Glup, H-4-Fucp), 4.31 (d, J = 7.6 Hz, 1H, H-1-Fucp), 4.08 (t, J = 8.4 Hz, 1H, H-
2-Fucp), 3.88 (dd, J = 12.0, 3.6 Hz, 1H, H-6-Glup), 3.85 (dd, J = 9.2, 3.6 Hz, 1H, H-3-Fucp),
3.77 (dd, J = 12.0, 4.4 Hz, 1H, H-6-Glup), 3.69 – 3.56 (m, 3H, H-4-Glup, H-5-Fucp, -CH2-CH-
CH2-), 3.55 – 3.49 (m, 1H, H-2-Glup), 3.40 – 3.31 (m, 1H, H-5-Glup), 2.50 – 2.28 (m, 4H), 2.13
(s, 3H, CH3-C=O), 1.88 – 1.78 (m, 6H, CH3-CH-C(CH3)-C=O), 1.60 – 1.46 (m, 2H), 1.40 – 1.22
(m, 6H), 1.14 (d, J = 6.4 Hz, 3H, H-6-Fucp), 0.97 – 0.83 (m, 12H), 0.80 (s, 9H), 0.15 (s, 3H,
CH3-Si), 0.11 (s, 6H, 2 × CH3-Si), 0.05 (d, J = 11.9 Hz, 3H, CH3-Si). 13C NMR (100 MHz,
CDCl3) δ 170.9, 169.1, 138.6, 134.8 128.2, 116.9, 101.6, 100.0, 81.5, 79.2, 75.3, 74.4, 73.9, 73.4,
73.3, 70.8, 68.8, 62.1, 39.6, 33.9 32.1, 25.8 (x3), 25.8 (x3), 25.3, 22.7, 21.0, 18.1, 17.6, 16.7,
14.4, 14.0, 12.0, –3.0, –3.9, –4.2, –5.2.
Diene 9a. DCC (853 mg, 4.14 mmol) was added in one portion to a 0ºC CH2Cl2 (200 mL)
solution of 29a (3.02 g, 3.76 mmol), 4-oxonon-8-eneoic acid 819 (703 mg, 4.14 mmol) and 4-
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 28 of 38
1
2
3
4
5
6
7
8
9
dimethylaminopyridine (46 mg, 0.38 mmol). The reaction was allowed to warm to ambient
temperature and stirred overnight. At this point, TLC (silica, 1:3 EtOAc–hexanes) showed the
reaction was complete. The reaction mixture was diluted with ether (100 mL) and hexanes (40
mL), stirred for 20 minutes then filtered thru a pad of celite using ether (50 mL) as the eluent and
the filtrate concentrated in vacuo. The residue was purified by column chromatography (silica,
EtOAc–hexanes, 1:6) gave diene 9a (2.51 g, 70%) as a colorless syrup. [α]D25 +9.2 (c 1 CHCl3).
1H NMR (400 MHz, CDCl3) δ 6.97 – 6.90 (m, 1H, Me-CH-C(Me)-C=O), 6.24 – 6.04 (m, 1H,
CH2=CH-CH2-), 5.82 – 5.70 (m, 1H, CH2=CH-CH2-), 5.20 – 4.88 (m, 7H, 2 × CH2=CH-CH2-,
H-1-Glup, H-3-Glup, H-4-Fucp), 4.43 (dd, J = 12.0, 4.4 Hz, 1H, H-6-Glup), 4.37 (d, J = 8.0 Hz,
1H, H-1-Fucp), 4.34 – 4.28 (dd, J = 12.0, 2.0 Hz, 1H, H-6-Glup), 4.06 (t, J = 9.2, 7.6 Hz, 1H, H-
2-Fucp), 3.89 (dd, J = 9.2, 3.6 Hz, 1H, H-3-Fucp), 3.68 – 3.47 (m, 4H, H-2-Glup, H-4-Glup, H-
5-Fucp, -CH2-CH-CH2-), 3.46 – 3.39 (m, 1H, H-5-Glup), 2.94 (d, J = 4.8 Hz, 1H, OH), 2.87 –
2.49 (m, 4H), 2.49 – 2.42 (m, 2H), 2.31 (t, J = 6.0 Hz, 2H), 2.13 (s, 3H, CH3-C=O), 2.09 – 2.00
(m, 2H), 1.88 – 1.77 (m, 6H, CH3-CH-C(CH3)-C=O), 1.74 – 1.47 (m, 4H), 1.42 – 1.19 (m, 6H),
1.14 (d, J = 6.4 Hz, 3H, H-6-Fucp), 0.92 – 0.82 (m, 12H), 0.80 (s, 9H), 0.13 (s, 3H, CH3-Si),
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
13
0.08 (s, 6H, 2 × CH3-Si), 0.02 (s, 3H, CH3-Si). C NMR (101 MHz, CDCl3) δ 208.6, 173.2,
170.9, 168.9, 138.5, 137.8, 136.1, 128.2, 116.2, 115.3, 100.8, 99.9, 80.8, 78.6, 74.1, 74.0, 73.8,
73.7, 73.4, 70.1, 68.9, 63.3, 41.8, 38.6, 37.1, 34.4, 33.0, 31.9, 27.7, 25.8 (x3), 25.8 (x3), 24.5,
22.7, 22.6, 21.0, 18.1, 17.6, 16.7, 14.4, 14.1, 12.0, –3.2, –4.0, –4.3, –5.3. IR (film): ν = 3482,
2930, 2857, 1736, 1717, 1653, 1641, 1257, 1074, 839, 762. HRMS (ESI) m/z calcd for
C49H86NaO14Si2 [M+Na]+ 977.5454, found: 977.5444.
Diene 9b. 9b (110 mg, 55%, colorless syrup) was prepared by treating 29b (176 mg, 0.22
mmol) with 4-oxonon-8-eneoic acid 819 (41.0 mg, 0.241 mmol) and 4-dimethylaminopyridine
(2.5 mg, 0.022 mmol) in distilled CH2Cl2 (10 mL) under the same conditions as described for the
synthesis of 9a. [α]D25 +4.2 (c 1 CHCl3). 1H NMR (300 MHz, CDCl3) δ 7.00 – 6.89 (m, 1H, Me-
CH-C(Me)-C=O), 5.95 – 5.69 (m, 2H, 2 x CH2=CH-CH2-), 5.12 – 4.89 (m, 7H, 2 × CH2=CH-
CH2-, H-1-Glup, H-3-Glup, H-4-Fucp), 4.41 (dd, J = 12.0, 4.4 Hz, 1H, H-6-Glup), 4.39 (d, J =
8.0 Hz, 1H, H-1-Fucp), 4.35 – 4.33 (dd, J = 12.0, 2.0 Hz, 1H, H-6-Glup), 4.08 (t, J = 9.2, 7.6 Hz,
1H, H-2-Fucp), 3.90 (dd, J = 9.2, 3.6 Hz, 1H, H-3-Fucp), 3.70 – 3.49 (m, 4H, H-2-Glup, H-4-
Glup, H-5-Fucp, -CH2-CH-CH2-), 3.48 – 3.40 (m, 1H, H-5-Glup), 2.94 (d, J = 4.8 Hz, 1H, OH),
2.82 – 2.55 (m, 4H), 2.52 – 2.41 (m, 2H), 2.38 (t, J = 6.0 Hz, 2H), 2.13 (s, 3H, CH3-C=O), 2.11 –
ACS Paragon Plus Environment

Page 29 of 38
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
2.01 (m, 2H), 1.89 – 1.77 (m, 6H, CH3-CH-C(CH3)-C=O), 1.76 – 1.65 (m, 4H), 1.42 – 1.21 (m,
6H), 1.14 (d, J = 6.4 Hz, 3H, H-6-Fucp), 0.97 – 0.85 (m, 12H), 0.80 (s, 9H), 0.15 (s, 3H, CH3-Si),
0.11 (s, 6H, 2 × CH3-Si), 0.04 (s, 3H, CH3-Si). 13C NMR (75 MHz, CDCl3) δ 208.7, 173.1, 171.0,
169.1, 138.7, 137.9, 135.0, 128.2, 116.9, 115.3, 101.1, 100.0, 81.0, 79.0, 74.3, 73.9, 73.8, 73.4,
70.4, 68.8, 63.6, 41.8, 39.6, 37.1, 33.8, 33.0, 32.3, 27.7, 25.8 (x3), 25.8 (x3), 25.3, 22.9, 22.7,
21.1, 18.1, 17.6, 16.7, 14.5, 14.3, 12.0, –3.1, –3.9, –4.2, –5.1.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
RCM/Hydrogenation Product 10a. To a solution of diene 9a (2.25 g, 2.36 mmol) in CH2Cl2
(500 mL) was added Hoveyda-Grubbs catalyst 2nd generation26,27 (148 mg, 0.24 mmol) in one
portion at room temperature. The reaction mixture was refluxed for 4 h. At this point, TLC
(silica, 1:2 EtOAc–hexanes) showed the reaction was complete. The reaction was cooled to
ambient temperature and then concentrated. Flash chromatography (silica, EtOAc–hexanes, 1:4
→ 1:2) gave isomer 30a (1.92 g, 88%) as a white foam which was not fully characterized. To a
solution of 30a (715 mg, 0.771 mmol) in EtOH (4 mL) was added Wilkinson’s catalyst (143 mg,
0.154 mmol) in one portion at room temperature. The reaction was then stirred under an
atmosphere of hydrogen (1 atm) overnight. At this point, TLC (silica, 1:2 EtOAc–hexanes)
showed the reaction was complete. The reaction mixture was filtered thru a pad of celite using
EtOAc (5 mL) as the eluent and the resulting filtrate concentrated. Flash chromatography (silica,
25
EtOAc–hexanes, 1:5 → 1:3) gave 10a (565 mg, 79%) as a colorless syrup. [α]D +17.3 (c 1
1
CHCl3). H NMR (400 MHz, CDCl3) δ 6.98 – 6.90 (m, 1H, Me-CH-C(Me)-C=O), 5.08 – 4.92
(m, 3H, H-1-Glup, H-3-Glup, H-4-Fucp), 4.75 (m, 1H, H-6-Glup), 4.38 (br, 1H, H-1-Fucp), 4.04
– 4.34 (m, 2H, H-6-Glup, H-2-Fucp), 3.99 – 3.89 (m, 1H, H-3-Fucp), 3.73 – 3.65 (m, 1H, H-5-
Fucp), 3.57 (br, 1H, H-5-Glup), 3.51 – 3.33 (m, 3H, H-2-Glup, H-4-Glup, -CH2-CH-CH2-), 3.13
– 3.06 (m, 1H, OH), 3.01 – 2.84 (m, 1H), 2.75 – 2.56 (m, 3H), 2.52 – 2.41 (m, 1H), 2.36 – 2.24
(m, 1H), 2.11 (s, 3H, CH3-C=O), 1.87 – 1.80 (m, 6H, CH3-CH-C(CH3)-C=O), 1.78 – 1.49 (m,
6H), 1.47 – 1.20 (m, 12H), 1.13 (d, J = 6.4 Hz, 3H, H-6-Fucp), 0.91 – 0.84 (m, 12H), 0.82 (s,
13
9H), 0.16 (s, 3H, CH3-Si), 0.11 (s, 3H, CH3-Si), 0.10 (s, 3H, CH3-Si), 0.01 (s, 3H, CH3-Si). C
NMR (100 MHz, CDCl3) δ 210.3, 172.4, 170.9, 168.0, 137.8, 128.5, 100.7, 100.2, 78.0, 74.5,
74.0, 73.9, 73.7, 69.0, 68.7, 63.3, 41.8, 37.1, 34.9, 33.5, 32.0, 29.6, 29.1, 28.5, 28.3, 25.9, 25.8
(x6), 25.2, 24.5, 23.4, 22.6, 20.9, 18.0, 17.6, 16.6, 14.4, 14.0, 12.0, –3.3, –4.0, –4.3, –5.1. IR
(film): ν = 3476, 2928, 2857, 1740, 1717, 1246, 1070, 837, 777. HRMS (ESI) m/z calcd for
C47H84NaO14Si2 [M+Na]+ 951.5297, found: 951.5288.
ACS Paragon Plus Environment