Hypervalent iodine mediated synthesis of C-2 deoxy glycosides and amino acid glycoconjugates

Article abstract of DOI:10.1021/jo500465m

A simple, efficient, and practical method for the synthesis of C-2 deoxy-2-iodo glycoconjugates in self-assembled structures was found using PhI(OCOR)₂. 2-Iodo glycoserinyl esters were intramolecularly converted into 2-iodo serinyl glycosides which upon dehalogenation gave C-2 deoxy amino acid glycoconjugates.

Full text of DOI:10.1021/jo500465m

Article
pubs.acs.org/joc
Hypervalent Iodine Mediated Synthesis of C‑2 Deoxy Glycosides and
Amino Acid Glycoconjugates
Maidul Islam, Nishanth D. Tirukoti, Shyamapada Nandi, and Srinivas Hotha*
Department of Chemistry, Indian Institute of Science Education and Research, Pune 411 008, India
S
* Supporting Information
ABSTRACT: A simple, efficient, and practical method for the
synthesis of C-2 deoxy-2-iodo glycoconjugates in self-
assembled structures was found using PhI(OCOR)2. 2-Iodo
glycoserinyl esters were intramolecularly converted into 2-iodo
serinyl glycosides which upon dehalogenation gave C-2 deoxy
amino acid glycoconjugates.
glycals.7 Therefore, we thought of studying the reaction of
hypervalent iodination on glycals in the presence of CTAB-
Stereo- and regioselective reactions are well sought after in
assembled self-assembled structures for the regioselective
organic chemistry; frequently, stereo- and regioselectivities are
synthesis of 2-deoxy-glycosides.
INTRODUCTION
■
obtained by taking advantage of steric environments such as
chiral auxiliaries, reagents, and solvents.1 The utility of self-
RESULTS AND DISCUSSION
To begin our investigation, a CH2Cl2 solution of per-O-acetyl
glucal 1a at 0 °C was added to PhI(OAc)2, CTAB, and KI. The
resulting turbid solution was stirred at room temperature for 6
assembled structures for the above is a promising alternative.2 It
■
is desirable that the self-assembled structure (i) is stable at the
temperature of the reaction; (ii) does not react with reagents;
(iii) does not disassemble during the reaction; and (iv) should
be accessible from simple precursors. It is known that
h to observe the formation of two inseparable products 2a and
3a in a 95:5 ratio which were characterized by NMR and MS
cetylammonium bromide (CTAB) forms organic solvent-stable
analysis (Scheme 1);10 importantly, no regioisomeric mixture
was noticed. The origin of selectivity is attributed to the
micellar environment as postulated earlier.5,10 The formation of
compound 3a is possible due to the halide counterion exchange
between CTAB and KI which was confirmed through a control
surfactant-assembled lipophilic nanoreactors.3 Addition of
polyvalent iodine reagents onto electron-rich π-systems was
found to be suitable for the current investigation since various
iodobenzene dicarboxylates react with electron-rich π-systems.4
Earlier studies showed that indenes can be regioselectively
functionalized using PhI(OAc)2 in CTAB derived nano-
reactors.5
Scheme 1. Synthesis of C-2 Deoxy C-2 Iodo Anomeric
Acetates in Self Assembled Structures
Easily available glycals possess an electron-rich π-bond, and
the utility of hypervalent iodine (IIII) reagents on glycals was
studied for the selective C3-O-oxidation, C-2 heteroatom
substitution, and oxidative glycosidation.6,7 In this premise,
regioselective iodination of glycals has been hypothesized
through surfactant-assembled structures by using CTAB and
polycoordinated iodine reagents for the synthesis of 2-deoxy-2-
iodo acetates. Notably, 2-deoxy-2-iodo glycopyranosyl acetates
are important precursors for the synthesis of 2-deoxy-, 2-alkyl,
and 2-amino glycosides. Biological significance and their
versatility coupled with the challenge of synthesizing 2-deoxy-
glycopyranosides7 had attracted many researchers to develop
strategies for their synthesis utilizing hypervalent iodine
reagent,7a−h de novo,8 and dehydrative7i glycosidation. 2-
Deoxy-glycopyranosides can be accessed through moderately
stable C-2 triflates,9 or by the addition of electrophilic iodine in
a poorly regioselective manner to the electron rich π-bond of
Received: February 26, 2014
Published: April 22, 2014
© 2014 American Chemical Society
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Scheme 2. Hypervalent Iodine for the Synthesis of C-2 Deoxy-2-iodo Anomeric Esters
experiment wherein KBr was added in place of KI to observe
compound 3a only (Scheme 1).
confirmed the presence of an iodo group in the manno-
configuration and α-configured ester moiety.10,13
A regioisomeric mixture of products was noticed in the
absence of CTAB. In addition, it is desirable to maintain the
CTAB concentration at a critical micellar concentration
(CMC) at 10 mol % for 15 mL in order to obtain self-
assembled structures;5a,10 otherwise, a regioisomeric mixture of
iodoacetates is observed. Both iodo- (2a) and bromo- (3a)
saccharides can be subjected to the Bu3SnH/AIBN reaction to
obtain corresponding 2-deoxy derivatives.11 Furthermore,
anomeric esters are important as they can be easily activated
by the addition of Lewis acids to obtain a variety of glycosides.
A similar reaction between per-O-acetyl galactal and PhI(OAc)2
in CTAB and KI gave corresponding iodo acetate 2b and
bromo acetate 3b with a 94:5 ratio of 2b:3b (Scheme 1). Acetyl
groups of the iodobenzene diacetate can be exchanged with
carboxylic acids by slow evaporation of a solution of an
equimolar mixture of PhI(OAc)2 and carboxylic acid (4a−4h)
in chlorobenzene around 50 °C over 1 h.12 The exchange
reaction worked well, and various PhI(OCOR)2 compounds
(5a−5h) were synthesized. Further, the generality of the
regioselective halo ester glycoside synthesis was investigated
with hypervalent iodine esters 5a−5h.
Amino acid glycoconjugates are interesting since they can be
easily converted to N-carboxy anhydrides (NCAs) for the
synthesis of glycopolypeptides by ring-opening polymerization
with amines in the presence of proton sponge.14 Additionally,
amino acid glycoconjugates 6g, 6h, 7c, 7d, 8d, and 8e are
correctly positioned to undergo intramolecular glycosidation in
the presence of a suitable Lewis acid. The activator not only is
able to cleave the silyl ether to give A, but also can perform as a
Lewis acid to facilitate the departure of the anomeric ester. The
resulting intermediate can further be attacked by the
nucleophile in an intramolecular fashion to result in acid B
(Figure 1). Subsequently, radical deiodination should give
access to 2-deoxy glycosides.
Gratifyingly, the formation of iodo ester glycosides in very
good yield along with a minor amount of bromo esters was
noticed. For example, the reaction between glucal and iodoso
esters 5a−h gave 2-deoxy-glycosyl esters 6a−h in very good
yields (Scheme 2).10 Similar products in good yields were
noticed with galactal (1b) and lactal (1c) to give products 7a−
d and 8a−e in good yields with selected phenyl iodosoesters
(Scheme 2). Good quality crystals of compound 6e could be
obtained by slow evaporation from ethyl acetate and light
petroleum (60−80 °C) and was subjected to X-ray structure
determination.10,13 The crystal structure of compound 6e
Figure 1. Rationale for the intramolecular aglycon delivery.
The biological significance of many natural products was
found to be dependent on the presence of 2-deoxy glycosides.15
However, the stereoselective synthesis of 2-deoxy glycosides is
still a challenge due to the absence of any directing group at the
C-2 position.16 It is interesting to observe that NIS mediated
amino acid glycoconjugate synthesis from glycals results16a in
the 2-iodo α-glycosides whereas the current protocol gives
access to β-glycosides in a stereoselective fashion.
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Scheme 3. Synthesis of C-2 Iodo Amino Acid Glycosides
Procedure for the Synthesis of Compounds 2a. A two-neck
round-bottom flask containing glucal (0.272 g, 1.0 mmol), anhydrous
MgSO4 (0.5 g), and CH2Cl2 (15 mL) at 0 °C was added to
PhI(OCOCH3)2 (0.644 g, 2.0 mmol), CTAB (0.039 g, 10 mol %), and
KI (0.166 g, 1.0 mmol). The reaction mixture was stirred at 25 °C for
6 h and diluted with water and extracted with CH2Cl2 (3 × 25 mL),
and the combined organic portions were washed with aq. sodium
bicarbonate and brine solution (2 × 10 mL), dried over anhydrous
sodium sulfate, and concentrated under reduced pressure. The
resulting crude residue was purified by silica gel column chromatog-
raphy using ethyl acetate and light petroleum ether (bp 60−70 °C) to
obtain compound 2a (0.389 g, 85%) as a colorless thick syrup. The
same general procedure was adopted for synthesizing compounds 2a−
2c, 3a, 6a−6h, 7a−7d, and 8a−8e.
After several experiments with amino acid glycoconjugate 6g,
a catalytic amount of TMSOTf in CH2Cl2 at −78 °C was found
to be suitable for this transformation (Scheme 3). Initially,
cleavage17 of silyl ether was noticed by TLC-MS analysis that
subsequently was converted to C-2-iodo serinyl glycoside as a
carboxylic acid in a very good yield; the acid was easily purified
by converting it to the corresponding methyl ester 9a under
EDCI/DMAP/MeOH conditions (Scheme 3). Similar results
were also observed with the threonine derivative 6h to obtain
9b in good yield. In addition, galacto-derived serine and
threonine anomeric esters 7c and 7d also underwent the
intramolecular glycosidation to give β-galactosyl amino acid
glycoconjugates 11a and 11b. Compounds 9a−b and 11a−b
were successfully subjected to radical mediated deiodination11
using Bu3SnH and AIBN in toluene at 120 °C to obtain 2-deoxy
β-glycosides 10a−b and 12a−b which are otherwise fairly
difficult to synthesize in a stereoselective manner.
Synthesis of Compound 9a. To C-2 deoxy 2-iodo amino acid
glycoconjugate 6g (0.750 g, 1.00 mmol) in CH2Cl2 (10 mL) was
added 4 Å molecular sieves powder (0.5 g) at room temperature. After
stirring for 30 min, the reaction mixture was cooled to −78 °C and
TMSOTf (45 μL, 0.25 mmol) was added and stirred for 30 min. The
reaction mixture was slowly warmed to 0 °C and stirred for 3 h,
diluted with CH2Cl2, and filtered through Celite. The filtrate was
subsequently neutralized with excess triethylamine and concentrated in
vacuo, and the residue was purified by silica gel column
chromatography to give 2-iodo acid which was directly used for
esterification. 2-Iodo acid (0.637 g, 1.00 mmol) was redissolved in
CH2Cl2 (10 mL), and MeOH (61 μL, 1.5 mmol) was added followed
by cooling to 0 °C. 1-(3-(Dimethylamino)propyl)-3-ethyl carbodii-
mide (EDCI) (0.249 g, 1.30 mmol), Et3N (181 μL, 1.30 mmol), and
DMAP (0.030 g, 0.25 mmol) were added and stirred for 20 h at 25 °C.
The reaction was quenched with water and extracted with CH2Cl2 (2
× 25 mL). The combined organic layers were washed with saturated
NaHCO3, water, and brine, dried, and concentrated in vacuo to obtain
a residue that was purified by silica gel column chromatography using
EtOAc and light petroleum (bp 60−70 °C) to afford compound 9a
(0.485 g, 76%) as a colorless thick syrup. The same general procedure
was adopted for synthesizing compounds 9b and 11a−11b.
CONCLUSIONS
■
We have identified a practical, efficient, simple, and fully
stereoselective method for the synthesis of 2-deoxy-2-iodo
glycosides in self-assembled structures. Various 2-iodo glycosyl
esters were synthesized in a stereoselective fashion. Intra-
molecular glycosidation of anomeric serinyl esters afforded β-
serinyl glycosides, and the radical mediated deiodination at C-2
position resulted in 2-deoxy serinyl glycosides. Further
investigation on the utilization of 2-deoxy serinyl glycosides
for the synthesis of glycopolypeptides and other materials is
currently underway.
EXPERIMENTAL SECTION
■
General Methods. Unless otherwise noted, materials were
obtained from commercial suppliers and were used without further
purification. Unless otherwise reported all reactions were performed
under an argon atmosphere. Removal of solvent in vacuo refers to
distillation using a rotary evaporator attached to an efficient vacuum
pump. Products obtained as solids or syrups were dried under high
vacuum. Analytical thin-layer chromatography was performed on
precoated silica plates (F254, 0.25 mm thickness); compounds were
visualized by UV light or by staining with anisaldehyde spray. Optical
rotations were measured on a polarimeter. IR spectra were recorded
on an FT-IR spectrometer. NMR spectra were recorded on either a
400 or 500 MHz spectrometer with CDCl3 as the solvent and TMS as
the internal standard. High resolution mass spectroscopy (HRMS) was
performed using a TOF mass analyzer. Low resolution mass
spectroscopy (LRMS) was performed on UPLC-MS.
Compound 2a. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material. Yield: (0.389 g, 85%); [α]D = +31.2 (c = 1.0,
1
CHCl3); H NMR (399.78 MHz, CDCl3) δ 2.07 (s, 3 H), 2.11 (s,
3H), 2.12 (s, 3H), 2.17 (s, 3H), 4.11 (ddd, 1H, J = 7.4, 4.9 Hz), 4.16
(dd, 1H, J = 12.3, 4.4 Hz), 4.23 (dd, 1H, J = 12.3, 4.4 Hz), 4.53 (dd,
1H, J = 4.3, 1.5 Hz), 4.59 (dd, 1H, J = 9.5, 4.4 Hz), 5.46 (t, 1H, J = 9.6
Hz), 6.39 (s, 1H); 13C NMR (100.53 MHz, CDCl3) δ 20.6, 20.7, 20.9,
20.9, 27.1, 61.8, 67.0, 68.6, 71.4, 94.7, 168.2, 169.3, 169.9, 170.7; IR
(CHCl3) ν 2925, 1747, 1216, 1048 cm−1; HRMS (TOF) m/z [M +
Na]+ calcd for C14H19INaO9 480.9971, found 480.9979.
Compound 2b. This compound is prepared using the above-
mentioned general procedure using 1b (0.272 g, 1 mmol) as the
starting material. Yield: (0.367 g, 80%); [α]D = +43.2 (c = 1.0,
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CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.98 (s, 3H), 2.03 (s, 3H),
2.08 (s, 3H), 2.13 (s, 3H), 4.12 (d, 2H, J = 6.6 Hz), 4.20−4.23 (m,
1H), 4.34 (td, 1H, J = 6.7, 1.9 Hz), 4.83 (t, 1H), 5.35−5.39 (m, 1H),
6.44 (d, 1H); 13C NMR (100.53 MHz, CDCl3) δ 18.8, 20.6, 20.8, 20.9,
28.9, 61.4, 64.7, 64.8, 69.0, 96.0, 168.2, 169.6, 170.0, 170.4; IR
(CHCl3) ν 2925, 1745, 1219, 1143 cm−1; HRMS (TOF) m/z [M +
Na]+ calcd for calcd for C14H19INaO9 480.9971, found 480.9979.
Compound 2c. This compound is prepared using the above-
mentioned general procedure using 1c (0.560 g, 1 mmol) as the
starting material. Yield: (0.560 g, 75%); [α]D = +17.0 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.98 (s, 3H), 2.07 (s, 9H),
2.14 (s, 3H), 2.16 (s, 3H), 2.17 (s, 3H), 3.91−3.96 (m, 1H), 4.07 (dd,
1H, J = 11.1, 6.9 Hz), 4.19 (m, 4H), 4.54 (dd, 1H, J = 12.1, 1.8 Hz),
4.60 (d, 1H, J = 7.9 Hz), 4.71 (dd, 1 H, J = 3.9, 1.6 Hz), 5.00 (dd, 1H,
J = 10.4, 3.5 Hz), 5.17 (dd, 1H, J = 10.4, 8.0 Hz), 5.36−5.38 (m, 1H),
5.43 (dd, 1H, J = 8.9, 3.9 Hz), 6.22 (d, 1H, J = 1.3 Hz); 13C NMR
(100.53 MHz, CDCl3) δ 20.5, 20.6 (4C), 20.8, 20.8, 22.6, 52.1, 61.1,
61.2, 66.7, 68.3, 69.1, 70.7, 70.9, 72.5, 73.4, 90.7, 101.2, 169.2, 169.4,
170.1, 170.1, 170.1, 170.1, 170.3, 170.4; IR (CHCl3) ν 2930, 1746,
1221, 1053 cm−1; HRMS (TOF) m/z [M + Na]+ calcd for
C26H35INaO17 769.0817, found 769.0816.
Compound 3a. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material. Yield: (0.292 g, 71%); [α]D = +31.0 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 2.07 (s, 3H), 2.11 (s, 6H),
2.18 (s, 3H), 4.11 (ddd, 1H, J = 10.0, 4.5, 2.5 Hz), 4.15 (dd, 1H, J =
12.4, 2.4 Hz), 4.24 (dd, 1H, J = 12.4, 4.5 Hz), 4.44 (dd, 1H, J = 3.9, 1.7
Hz), 5.20 (dd, 1H, J = 9.7, 4.0 Hz), 5.49 (t, 1H, J = 9.8 Hz), 6.32 (d,
1H, J = 1.5 Hz); 13C NMR (100.53 MHz, CDCl3) δ 20.5, 20.6, 20.7,
20.8, 47.8, 61.8, 65.5, 68.7, 71.2, 93.1, 168.0, 169.2, 170.0, 170.6; IR
(CHCl3) ν 2925, 1745, 1219, 1143 cm−1; HRMS (TOF) m/z [M +
Na]+ calcd for C14H19BrNaO9 433.0110, 435.0090, found 433.0078,
435.0087.
starting material. Yield: (0.447 g, 72%); [α]D = +19.9 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 2.06 (s, 3H), 2.10 (s, 6H),
2.67 (t, 2H, J = 5.8 Hz), 3.51 (q, 2H, J = 6.0 Hz), 4.07−4.18 (m, 2H),
4.21 (dd, 1H, J = 12.4, 4.4 Hz), 4.52 4.58 (m, 2H), 5.10 (s, 2H), 5.36
(t, 1H, J = 6.1 Hz), 5.46 (t, 1H, J = 9.4 Hz), 6.41 (s, 1H), 7.35 (m,
5H); 13C NMR (100.53 MHz, CDCl3) δ 20.6, 20.7, 20.9, 26.9, 34.3,
36.4, 61.7, 66.8(2C), 68.6, 71.5, 94.9, 128.0−128.5 (5C), 136.2, 156.3,
169.3, 169.8, 169.9, 170.7; IR (CHCl3) ν 3396, 3051, 2958, 1742,
1520, 1130, 1005 cm−1; HRMS (TOF) m/z [M + Na]+ calcd for
C23H28INNaO11 644.0605, found 644.0597.
Compound 6e. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material. Yield: (0.470 g, 80%); mp: 131 °C; [α]D = +7.80 (c =
1.0, CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.45 (s, 9H), 1.46 (s,
3H), 2.08 (s, 3H), 2.11 (s, 3H), 2.12 (s, 3H), 4.16 (dd, 2H, J = 14.0,
11.1 Hz), 4.24 (dd, 1H, J = 12.0, 4.0 Hz), 4.31−4.40 (m, 1H), 4.51−
4.60 (m, 2H), 5.02 (d, 1H, J = 7.1 Hz), 5.48 (t, 1H, J = 9.4 Hz), 6.40
(s, 1H); 13C NMR (100.53 MHz, CDCl3) δ 18.1, 21.0, 20.7, 20.9, 26.7,
28.2 (3C), 49.0, 61.6, 66.7, 68.7, 71.6, 80.2, 95.5, 155.0, 169.3, 169.8,
170.7, 171.1; IR (CHCl3) ν 3384, 2981, 1747, 1515, 1454, 1160, 1057,
666 cm−1; HRMS (TOF) m/z [M + Na]+ calcd for [C20H30INNaO11
610.0761, found 610.0770.
Compound 6f. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material. Yield: (0.550 g, 81%); [α]D = +40.0 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.45 (s, 9H), 2.08 (s, 3H),
2.11 (s, 3H), 2.12 (s, 3H), 2.93−3.04 (m, 2H), 3.79 (s, 3H), 4.10−
4.19 (m, 2H), 4.23 (dd, 1H, J = 12.3, 4.4 Hz), 4.53 (dd, 1H, J = 9.5,
4.4 Hz), 4.57−4.66 (m, 2H), 5.46 (t, 1H, J = 9.7 Hz), 5.58 (d, 1H, J =
8.0 Hz), 6.38 (s, 1H); 13C NMR (100.53 MHz, CDCl3) δ 20.5, 20.6,
20.8, 26.8, 28.2 (3C), 36.9, 49.9, 52.8, 61.6, 66.8, 68.5, 71.6, 80.3, 95.3,
155.1, 168.4, 169.2, 169.7, 170.6, 171.0; IR (CHCl3) ν3374, 2977,
1745, 1510, 1438, 1162, 1056, 669 cm−1; HRMS (TOF) m/z [M +
Na]+ calcd for C22H32INNaO13 668.0816, found 668.0789
Compound 6g. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material. Yield: (0.603 g, 81%); [α]D = +8.0 (c = 1.0, CHCl3);
1H NMR (399.78 MHz, CDCl3) δ 0.03 (s, 3H), 0.04 (s, 3H), 0.85 (s,
9H), 2.05 (s, 3H), 2.09 (s, 3H), 2.11 (s, 3H), 3.88 (dd, 1H, J = 10.3,
3.1 Hz), 4.08−4.11 (m, 2H), 4.11−4.14 (m, 1H), 4.23 (dd, 1H, J =
12.5, 4.3 Hz), 4.46−4.49 (m, 1H), 4.50 (dd, 1H, J = 4.4, 1.5 Hz), 4.58
(dd, 1H, J = 9.5, 4.4 Hz), 5.15 (d, 2H, J = 10.9 Hz), 5.46 (t, 1H, J = 9.8
Hz), 5.58 (d, 1H, J = 8.5 Hz), 6.42 (s, 1H), 7.32−7.39 (m, 5H); 13C
NMR (100.53 MHz, CDCl3) δ −5.7, −5.6, 18.2, 20.6, 20.7, 20.8, 25.7
(3C), 26.6, 56.0, 62.0, 63.4, 66.8, 67.3, 68.4, 71.6, 95.6, 128.2−128.6
(5C), 136.0, 155.9, 168.1, 169.3, 170.0, 170.7; IR (CHCl3) ν 3365,
2934, 1747, 1512, 1427, 1117, 1056, 668 cm−1; HRMS (TOF) m/z
[M + Na]+ calcd for C29H42INNaO12Si 774.1419, found 774.1423.
Compound 6h. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material, Yield: (0.605 g, 79%); [α]D = +5.4 (c = 1.0, CHCl3);
1H NMR (399.78 MHz, CDCl3) δ 0.00 (s, 3H), 0.05 (s, 3H), 0.82 (s,
9H), 1.24 (d, 3H, J = 6.2 Hz), 2.03 (s, 3H), 2.09 (s, 6H), 3.98−4.14
(m, 2H), 4.22 (dd, 1H, J = 12.8, 4.3 Hz), 4.31 (dd, 1H, J = 9.3, 1.7
Hz), 4.40−4.62 (m, 3H), 5.16 (d, 2H, J = 6.6 Hz), 5.46 (t, 2H, J = 9.2
Hz), 6.39 (s, 1H), 7.29−7.41 (m, 5H); 13C NMR (100.53 MHz,
CDCl3) δ −5.4, −4.4, 17.8, 20.5, 20.6, 20.7, 20.8, 25.5(3C), 26.6, 60.0,
61.4, 66.6, 67.3, 68.4, 68.5, 71.5, 95.5, 128.2−128.5 (5C), 135.9, 156.5,
168.4, 169.2, 169.6, 171.0; IR (CHCl3) ν 3445, 2955, 1744, 1512,
1426, 1136, 1063, 698 cm−1; HRMS (TOF) m/z [M + Na]+ calcd for
C30H44INNaO12Si 788.1575, found 788.1581.
Compound 6a. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material. Yield: (0.356 g, 76%); [α]D = +61.0 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 2.08 (s, 3H), 2.12 (s, 3H),
2.12 (s, 3H), 3.07 (s, 1 H), 4.13−4.19 (m, 2 H), 4.24 (dd, 1H, J =
12.7, 4.8 Hz), 4.59 (bs, 1H), 4.60 (d, 1H, J = 6.0 Hz), 5.41 5.53 (m,
1H), 6.47 (s, 1H); 13C NMR (100.53 MHz, CDCl3) δ 20.6, 20.7, 20.9,
26.2, 61.6, 66.7, 68.4, 71.8, 73.3, 77.1, 96.0, 149.7, 169.3, 169.8, 170.6;
IR (CHCl3) ν 3258, 2950, 1741, 1145, 1059 cm−1; HRMS (TOF) m/z
[M + Na]+ calcd for C15H17INaO9 490.9815, found 490.9825.
Compound 6b. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material, Yield: (0.437 g, 73%); [α]D = +25.8 (c = 1.0,
1
CHCl3); H NMR (399.78 MHz, CDCl3) δ 0.82 0.92 (m, 3 H), 1.21
1.37 (m, 16 H), 1.65 (q, 2H, J = 7.3 Hz), 2.07 (s, 3H), 2.11 (s, 3H),
2.11 (s, 3H), 2.40 (t, 1H, J = 7.5 Hz), 4.11 (ddd, 1H, J = 9.9, 4.6, 2.5
Hz), 4.15 (dd, 1H, J = 12.4, 2.4 Hz), 4.22 (dd, 1H, J = 12.3, 4.6 Hz),
4.53 (dd, 1H, J = 4.4, 1.6 Hz), 4.58 (dd, 1H, J = 9.4, 4.4 Hz), 5.45 (t,
1H, J = 9.7 Hz), 6.40 (d, 1H, J = 1.4 Hz); 13C NMR (100.53 MHz,
CDCl3) δ 14.0, 20.5, 20.6, 20.7, 22.5, 24.6, 27.2, 28.8, 29.1, 29.2, 29.3,
29.4(2C), 31.8, 33.9, 61.7, 66.9, 68.6, 71.3, 94.3, 169.2, 169.7, 170.5,
170.8; IR (CHCl3) ν 2932, 1745, 1132, 1045 cm−1; HRMS (TOF) m/
z [M + Na]+ calcd for C24H39INaO9 621.1536, found 621.1547.
Compound 6c. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
starting material. Yield: (0.517 g, 80%); [α]D = +27.6 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 2.07 (s, 3H), 2.12 (s, 3H),
2.12 (s, 3H), 4.14 4.33 (m, 3H), 4.75 (d, 1H, J = 2.1 Hz), 4.78 (d, 1H,
J = 4.5 Hz), 5.47−5.59 (m, 1H), 6.67 (s, 1H), 7.22 (td, 1H, J = 7.6, 1.7
Hz), 7.47 (td, 1H, J = 7.6, 1.1 Hz), 7.83 (dd, 1H, J = 7.8, 1.6 Hz), 8.04
(dd, 1H, J = 7.9, 1.0 Hz); 13C NMR (100.53 MHz, CDCl3) δ 20.6,
20.8, 20.9, 27.0, 61.8, 66.9, 68.8, 72.0, 93.9, 96.1, 128.2, 131.6, 133.4,
133.5, 141.6, 163.9, 169.3, 169.9, 170.7; IR (CHCl3) ν 3013, 2931,
1746, 1551, 1441, 1121, 1033, 661 cm−1; HRMS (TOF) m/z [M +
Na]+ calcd for C19H20I2NaO9 668.9094, found 668.9141.
Compound 7a. This compound is prepared using the above-
mentioned general procedure using 1b (0.272 g, 1 mmol) as the
starting material. Yield: (0.472 g, 76%); [α]D = +41.2 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 2.01 (s, 3H), 2.08 (s, 3H),
2.18 (s, 3H), 2.51−2.69 (m, 2H), 3.48 (dt, 2H, J = 13.6, 6.4 Hz), 4.16
(d, 2H, J = 6.6 Hz), 4.30 (d, 1H, J = 4.6 Hz), 4.38 (t, 1H, J = 5.9 Hz),
4.84−4.88 (m, 1H), 5.08 (s, 2H), 5.40−5.42 (m, 2H), 6.52 (d, 1H, J =
1.2 Hz), 7.31−7.37 (m, 5H); 13C NMR (100.53 MHz, CDCl3) δ 18.6,
20.5, 20.7, 20.8, 34.3, 36.3, 61.4, 64.6, 64.7, 66.7, 69.0, 96.1, 128.0−
Compound 6d. This compound is prepared using the above-
mentioned general procedure using 1a (0.272 g, 1 mmol) as the
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128.4 (5C), 136.1, 156.2, 169.4, 169.7, 169.9, 170.4; IR (CHCl3) ν
3383, 2951, 1745, 1519, 1427, 1130, 1059, 666 cm−1; HRMS (TOF)
m/z [M + Na]+ calcd for C23H28INNaO11 644.0605, found 644.0617.
Compound 7b. This compound is prepared using the above-
mentioned general procedure using 1b (0.272 g, 1 mmol) as the
starting material. Yield: (0.487 g, 83%); [α]D = +22.4 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.42 (s, 3H), 1.44 (s, 9H),
2.05 (s, 3H), 2.09 (s, 3H), 2.19 (s, 3H), 4.12−4.25 (m, 2H), 4.31 (d,
2H, J = 4.3 Hz), 4.47 (t, 1H, J = 6.1 Hz), 4.86 4.91 (m, 1H), 5.20 (m,
1H, J = 7.3 Hz), 5.45 (s, 1H), 6.52 (s, 1H); 13C NMR (100.53 MHz,
CDCl3) δ 17.7, 18.5, 20.5, 20.6, 20.7, 28.1 (3C), 49.0, 61.2, 64.6 (2C),
69.0, 79.9, 96.5, 154.9, 169.2, 169.7, 170.2, 170.8; IR (CHCl3) ν 3372,
2980, 1748, 1515, 1427, 1166, 1060, 670 cm−1; HRMS (TOF) m/z
[M + Na]+ calcd for C20H30INNaO11 610.0761, found 610.0771.
Compound 7c. This compound is prepared using the above-
mentioned general procedure using 1b (0.272 g, 1 mmol) as the
starting material. Yield: (0.556 g, 74%); [α]D = +20.6 (c = 1.0,
68.8, 69.1, 70.4, 70.6, 71.6, 75.0, 80.0, 95.0, 101.1, 154.8, 169.0, 169.2,
169.7, 169.8, 170.1 (2C), 171.1; IR (CHCl3) ν 3382, 2981, 1747,
1514, 1453, 1164, 1053, 666 cm−1; HRMS (TOF) m/z [M + Na]+
calcd for C32H46INNaO19 898.1606, found 898.1613.
Compound 8c. This compound is prepared using the above-
mentioned general procedure using 1c (0.560 g, 1 mmol) as the
starting material. Yield: (0.774 g, 80%); [α]D = +35.4 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.45 (s, 9H), 1.98 (s, 3H),
2.08 (s, 6H), 2.15 (s, 6H), 2.17 (s, 3H), 2.90−3.09 (m, 2H), 3.78 (s,
3H), 3.95 (t, 1H, J = 6.7 Hz), 4.01−4.15 (m, 4H), 4.18 (dd, 1H, J =
11.2, 6.7 Hz), 4.46 (dd, 1H, J = 12.0, 1.5 Hz), 4.54 (s, 1H), 4.61 (dd,
3H, J = 12.1, 7.4 Hz), 5.00 (dd, 1H, J = 10.4, 3.5 Hz), 5.15 (dd, 1H, J =
10.4, 7.9 Hz), 5.32 5.43 (m, 1H), 5.50 (d, 1H, J = 8.1 Hz), 6.33 (d, 1H,
J = 2.0 Hz); 13C NMR (100.53 MHz, CDCl3) δ 20.5, 20.6, 20.6, 20.7,
20.8, 20.9, 27.0, 28.2 (3C), 36.9, 49.9, 52.9, 61.1, 61.6, 66.8, 69.0, 69.1,
70.7, 70.9, 72.0, 75.2, 80.4, 95.2, 101.4, 155.2, 168.7, 169.3, 169. 5,
170.0, 170.1, 170.4 (2C), 171.1; IR (CHCl3) ν 3678, 2929, 1746,
1512, 1434, 1164, 1052, 756 cm−1; HRMS (TOF) m/z [M + Na]+
calcd for C34H48INNaO21 956.1661, found 956.1667.
Compound 8d. This compound is prepared using the above-
mentioned general procedure using 1c (0.560 g, 1 mmol) as the
starting material. Yield: (0.832 g, 80%); [α]D = +18.0 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 0.03 (s, 3H), 0.04 (s, 3H),
0.85 (s, 9H), 1.98 (s, 3H), 2.07 (s, 6H), 2.10 2.18 (m, 9H), 3.88 (dd,
1H, J = 10.4, 3.1 Hz), 3.94 (t, 1H, J = 6.7 Hz), 3.97 4.04 (m, 1H), 4.07
(m, 4H), 4.18 (dd, 1H, J = 11.2, 6.7 Hz), 4.41 (d, 1H, J = 13.6 Hz),
4.41−4.53 (m, 2H), 4.61 (d, 1H, J = 7.9 Hz), 4.72 (dd, 1H, J = 7.0, 4.1
Hz), 5.00 (dd, 1H, J = 10.4, 3.4 Hz), 5.06−5.23 (m, 3H), 5.37 (d, 1H,
J = 3.2 Hz), 5.58 (d, 1H, J = 8.6 Hz), 6.39 (d, 1H, J = 2.4 Hz), 7.32−
7.40 (m, 5H); 13C NMR (100.53 MHz, CDCl3) δ −5.6, −5.6, 18.1,
20.5, 20.6, 20.6, 20.7, 20.8, 20.9, 25.7 (3C), 26.5, 55.9, 61.1, 61.6, 63.3,
66.7, 67.2, 69.0, 69.3, 70.7, 70.9, 71.8, 75.4, 95.4, 101.4, 128.2−128.5
(5C), 136.1, 155.9, 168.3, 169.2, 169.2, 170.0, 170.1, 170.4 (2C); IR
(CHCl3) ν 3369, 2935, 1748, 1514, 1425, 1112, 1057, 699 cm−1;
HRMS (TOF) m/z [M + K]+ calcd for C41H58IKNO20Si 1078.2003,
found 1078.2015.
1
CHCl3); H NMR (399.78 MHz, CDCl3) δ −0.07 (s, 3H), −0.05 (s,
3H), 0.76 (s, 9H), 1.94 (s, 3H), 1.99 (s, 3H), 2.10 (s, 3H), 3.79 (dd,
1H, J = 10.3, 3.1 Hz), 3.99 (dd, 1H, J = 10.3, 2.7 Hz), 4.07 (dd, 1H, J =
15.6, 6.6 Hz), 4.16 (d, 1H, J = 4.9 Hz), 4.25−4.32 (m, 1H), 4.38 (dt,
1H, J = 8.3, 2.8 Hz), 4.71 4.79 (m, 1H), 5.05 (d, 2H, J = 4.4 Hz), 5.34
(s, 1H), 5.52 (d, 1H, J = 8.4 Hz), 6.46 (s, 2H), 7.24−7.30 (m, 5H);
13C NMR (100.53 MHz, CDCl3) δ −5.7, −3.7, 18.0, 18.0, 20.5, 20.7,
20.9, 25.6 (3C), 25.7, 61.3, 63.3, 64.5, 64.6, 67.2, 69.3, 97.2, 128.2−
128.5 (5C), 136.0, 155.9, 168.1, 169.3, 170.0, 170.3; IR (CHCl3) ν
3367, 2953, 1748, 1513, 1464, 1130, 1058, 670 cm−1; HRMS (TOF)
m/z [M + Na]+ calcd for C29H42INNaO12Si 774.1419, found
774.1425.
Compound 7d. This compound is prepared using the above-
mentioned general procedure using 1b (0.272 g, 1 mmol) as the
starting material. Yield: (0.689 g, 90%); [α]D = +29.4 (c = 1.0,
1
CHCl3); H NMR (399.78 MHz, CDCl3) δ −0.05 (s, 3H), 0.00 (s,
3H), 0.78 (s, 9H), 1.20 (d, 3H, J = 6.2 Hz), 1.97 (s, 3H), 2.04 (s, 3H),
2.13 (s, 3H), 4.00−4.07 (m, 1H), 4.12 (ddd, 1H, J = 11.3, 6.5, 1.4 Hz),
4.20−4.25 (m, 2H), 4.28 (t, 1H, J = 6.6 Hz), 4.35−4.43 (m, 1H), 4.77
(t, 1H, J = 3.5 Hz), 5.08−5.16 (m, 2H), 5.36 (s, 1H), 5.41 (d, 1H, J =
8.9 Hz), 6.47 (s, 1H), 7.25−7.39 (m, 5H); 13C NMR (100.53 MHz,
CDCl3) δ −5.4, −4.3, 17.8, 18.1, 20.6, 20.8, 20.9, 20.9, 25.5(3C), 60.0,
61.3, 64.5, 64.6, 67.3, 68.4, 69.3, 97.3, 128.3, 128.6, 136.0, 156.6, 168.6,
169.3, 169.9, 170.3; IR (CHCl3) ν 3446, 2934, 1749, 1511, 1426,
1136, 1067, 699 cm−1; HRMS (TOF) m/z [M + Na]+ calcd for
C30H44INNaO12Si 788.1575, found 788.1572.
Compound 8e. This compound is prepared using the above-
mentioned general procedure using 1c (0.560 g, 1 mmol) as the
starting material. Yield: (0.811 g, 77%); [α]D = +13.0 (c = 1.0,
1
CHCl3); H NMR (399.78 MHz, CDCl3) δ −0.07 (s, 3H), −0.02 (s,
3H), 0.75 (s, 9H), 1.17 (d, 3H, J = 6.2 Hz), 1.89 (s, 3H), 1.99 (s, 6H),
2.02 (s, 3H), 2.05 (s, 3H), 2.07 (s, 3H), 3.85 3.95 (m, 2H), 3.96−4.05
(m, 2H), 4.09 (dd, 2H, J = 11.2, 6.8 Hz), 4.23 (dd, 1H, J = 9.4, 1.6
Hz), 4.35 (m, 2H), 4.46 (dd, 1H, J = 4.0, 2.2 Hz), 4.55 (d, 1H, J = 7.9
Hz), 4.59 (dd, 1H, J = 8.0, 4.8 Hz), 4.93 (dd, 1H, J = 10.4, 3.3 Hz),
5.00−5.14 (m, 3H), 5.29 (d, 1H, J = 3.3 Hz), 5.40 (d, 1H, J = 9.5 Hz),
6.29 (d, 1H, J = 1.9 Hz), 7.23−7.36 (m, 5H); 13C NMR (100.53 MHz,
CDCl3) δ −5.5, −4.4, 17.7, 20.4, 20.4, 20.5, 20.5, 20.6, 20.7, 20.7, 25.4
(3C), 26.8, 59.8, 61.0, 61.4, 66.6, 67.2, 68.4, 68.9, 69.1, 70.5, 70.8, 71.7,
74.9, 95.2, 101.1, 128.1−128.4 (5C), 136.0, 156.4, 168.9, 169.1, 169.1,
169.9, 169.9, 170.2, 170.3; IR (CHCl3) ν 3445, 2932, 1745, 1512,
1462, 1134, 1071, 698 cm−1; HRMS (TOF) m/z [M + K]+ calcd for
C42H60IKNO20Si 1092.2160, found 1092.2193.
Compound 8a. This compound is prepared using the above-
mentioned general procedure using 1c (0.560 g, 1 mmol) as the
starting material. Yield: (0.691 g, 76%); [α]D = +31.5 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.98 (s, 3H), 2.06 (s, 3H),
2.07 (s, 3H), 2.12 (s, 3H), 2.15 (s, 3H), 2.16 (s, 3H), 2.65 (t, 2H, J =
5.8 Hz), 3.50 (q, 2H, J = 5.9 Hz), 3.92 3.98 (m, 1H), 3.99 4.14 (m,
4H), 4.18 (dd, 1H, J = 11.3, 6.8 Hz), 4.43 (dd, 1H, J = 12.1, 1.7 Hz),
4.49−4.54 (m, 1H), 4.61 (d, 1H, J = 8.0 Hz), 4.67 (dd, 1H, J = 7.2, 4.1
Hz), 5.00 (dd, 1H, J = 10.5, 3.5 Hz), 5.10 (s, 2H), 5.16 (dd, 1H, J =
10.4, 7.9 Hz), 5.30 (t, 1H, J = 6.0 Hz), 5.36 5.40 (m, 1H), 6.35 (d, 1H,
J = 2.5 Hz), 7.32 7.38 (m, 5H); 13C NMR (100.53 MHz, CDCl3) δ
20.5, 20.6 (2C), 20.7, 20.8, 21.0, 26.9, 34.4, 36.4, 61.1, 61.7, 66.7, 66.8,
69.0, 69.4, 70.7, 70.9, 71.8, 75.4, 94.7, 101.4, 128.1−128.5 (5C), 136.3,
156.2, 169.3, 169.5, 170.0, 170.1 (2C), 170.4 (2C); IR (CHCl3) ν
3378, 2929, 1747, 1516, 1461, 1133, 1076, 668 cm−1; HRMS (TOF)
m/z [M + Na]+ calcd for C35H44INNaO19 932.1449, found 932.1443.
Compound 8b. This compound is prepared using the above-
mentioned general procedure using 1c (0.560 g, 1 mmol) as the
starting material. Yield: (0.727 g, 83%); [α]D = +25.8 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.44 (s, 9H), 1.98 (s, 3H),
2.03 (s, 3H), 2.08 (d, 6H, J = 1.1 Hz), 2.14 (s, 3H), 2.15 (s, 3H), 2.17
(s, 3H), 3.99 (t, 1H, J = 6.6 Hz), 4.05−4.13 (m, 3H), 4.14−4.21 (m,
2H), 4.29−4.36 (m, 1H), 4.43 (d, 1H, J = 11.8 Hz), 4.50−4.55 (m,
1H), 4.64 (d, 1H, J = 7.9 Hz), 4.68 (s, 1H), 5.02 (dd, 1H, J = 0.4, 3.3
Hz), 5.15 (dd, 1H, J = 10.4, 8.1 Hz), 5.23 (d, 1H, J = 7.1 Hz), 5.38 (d,
1H, J = 3.4 Hz), 6.35 (s, 1H); 13C NMR (100.53 MHz, CDCl3) δ 17.7,
20.2, 20.3 (2C), 20.4, 20.5, 20.7, 26.7, 28.0 (3C), 48.9, 61.0, 61.4, 66.6,
Compound 9a. This compound is prepared using the above-
mentioned general procedure using 6g (0.750 g, 1 mmol) as the
starting material. Yield: (0.494 g, 76%); [α]D = +40.7 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 2.03 (s, 3H), 2.07 (s, 3H),
2.09 (s, 3H), 3.80 (s, 3H), 3.92−4.01 (m, 3H), 4.12 (dd, 1H, J = 12.3,
2.3 Hz), 4.18 (dd, 1H, J = 12.3, 5.0 Hz), 4.48 (dd, 1H, J = 4.3, 1.3 Hz),
4.54 (dt, 2H, J = 9.2, 5.6 Hz), 5.14 (d, 3H, J = 5.8 Hz), 5.31 (t, 1H, J =
9.6 Hz), 5.82 (d, 1H, J = 8.2 Hz), 7.31−7.39 (m, 5H); 13C NMR
(100.53 MHz, CDCl3) δ 20.5, 20.6, 20.8, 28.5, 52.8, 54.1, 61.9, 67.1,
68.7 (2C), 68.9, 69.6, 101.8, 128.0−128.4 (5C), 135.9, 155.7, 169.3,
169.6, 170.0, 170.5; IR (CHCl3) ν 3378, 2930, 1742, 1519, 1452,
1123, 1051, 699 cm−1; HRMS (TOF) m/z [M + Na]+ calcd for
C24H30INNaO12 674.0710, found 674.0709.
Compound 9b. This compound is prepared using the above-
mentioned general procedure using 6h (0.750 g, 1 mmol) as the
starting material. Yield: (0.485 g, 73%); [α]D = +35.6 (c = 1.0,
CHCl3); 1H NMR (400 MHz, CDCl3) δ 1.31 (d, 3H, J = 6.4 Hz), 2.05
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(s, 3H), 2.07 (s, 3H), 2.09 (s, 3H), 3.78 (s, 3H), 4.06 (ddd, 1H, J =
9.8, 5.2, 2.4 Hz), 4.13 (dd, 1H, J = 12.2, 2.3 Hz), 4.20 (dd, 1H, J =
12.2, 5.3 Hz), 4.32−4.39 (m, 2H), 4.44 (dd, 1H, J = 9.7, 2.3 Hz), 4.53
(dd, 1H, J = 9.3, 4.3 Hz), 5.16 (d, 3H, J = 9.4 Hz), 5.31 (t, 1H, J = 9.6
Hz), 5.48 (d, 1H, J = 9.6 Hz), 7.30−7.44 (m, 5H); 13C NMR (101
MHz, CDCl3) δ 17.8, 20.6, 20.6, 20.9, 28.8, 52.7, 58.5, 62.2, 67.3, 67.5,
68.7, 69.7, 77.3, 102.6, 128.2−128.5 (5C), 135.9, 156.5, 169.4, 169.7,
170.6, 170.6; IR (CHCl3) ν 3358, 2950, 1744, 1518, 1452, 1175, 1038,
643 cm−1; HRMS (TOF) m/z [M + Na]+ calcd for C25H32INNaO12
688.0867, found 688.0861.
5H); 13C NMR (100.53 MHz, CDCl3) δ 20.7, 20.7, 20.8, 29.9, 52.7,
54.2, 62.4, 65.8, 66.4, 67.2 (2C), 68.4, 98.2, 128.1−128.5 (5C), 136.0,
155.9, 170.0, 170.2, 170.4, 170.5; IR (CHCl3) ν 3356, 2956, 1744,
1519, 1449, 1164, 1033, 701 cm−1; HRMS (TOF) m/z [M + Na]+
calcd for C24H31N NaO12 548.1744, found 548.1754.
Compound 12b. This compound is prepared by the reported
procedure11 using 11b (0.400 g, 0.6 mmol) as the starting material.
1
Yield: (0.209 g, 63%); [α]D = +102.8 (c = 1.0, CHCl3); H NMR
(399.78 MHz, CDCl3) δ 1.30 (d, 3H, J = 6.4 Hz), 1.70 (dd, 1H, J =
12.7, 5.0 Hz), 1.98 (s, 3H), 2.04 (s, 3H), 2.04 (m, 1H), 2.12 (s, 3H),
3.75 (s, 3H), 4.07 (dd, 2H, J = 6.4, 2.2 Hz), 4.18 (t, 1H, J = 6.5 Hz),
4.35 (dd, 1 H, J = 6.4, 2.1 Hz), 4.39 (dd, 1H, J = 9.8, 2.1 Hz), 4.98 (d,
1H, J = 3.2 Hz), 5.15 (s, 2H), 5.15−5.21 (m, 1H), 5.31 (d, 1H, J = 2.1
Hz), 5.44 (d, 1H, J = 9.7 Hz), 7.32−7.41 (m, 5H); 13C NMR (100.53
MHz, CDCl3) δ 18.3, 20.6, 20.7, 20.8, 30.2, 52.5, 58.6, 62.5, 65.8, 66.5,
67.1, 67.2, 76.1, 99.1, 128.1−128.5 (5C), 136.0, 156.5, 170.1, 170.2,
170.4, 171.1; IR (CHCl3) ν 3358, 2955, 1744, 1517, 1452, 1169, 1028,
701 cm−1; HRMS (TOF) m/z [M + Na]+ calcd for C25H33NNaO12
562.1900, found 562.1909.
Compound 10a. This compound is prepared by the reported
procedure11 using 9a (0.400 g, 0.6 mmol) as the starting material.
1
Yield: (0.210 g, 65%); [α]D = +48.6 (c = 1.0, CHCl3); H NMR
(399.78 MHz, CDCl3) δ 1.73 (td, 1H, J = 12.9, 3.7 Hz), 1.93 (s, 3H),
1.95 (s, 3H), 2.00 (s, 3H), 2.13 (dd, 1H, J = 13.1, 5.3 Hz), 3.71 (s,
3H), 3.84 (s, 3H), 3.96 (d, 1H, J = 12.2 Hz), 4.19 (dd, 1H, J = 12.2,
4.7 Hz), 4.48 (d, 1H, J = 8.0 Hz), 4.82−4.93 (m, 2H), 5.07 (s, 2H),
5.15 (td, 1H, J = 11.0, 5.4 Hz), 5.67 (d, 1H, J = 8.4 Hz), 7.24−7.33 (m,
5H); 13C NMR (100.53 MHz, CDCl3) δ 20.7 (2C), 20.9, 34.7, 52.7,
54.2, 62.1, 67.2, 68.3, 68.4, 68.7, 69.0, 97.7, 128.1−128.5 (5C), 136.0,
155.8, 169.8, 170.1, 170.3, 170.7; IR (CHCl3) ν 3356, 2956, 1740,
1518, 1450, 1132, 1047, 668 cm−1; HRMS (TOF) m/z [M + Na]+
calcd for C24H31NNaO12 548.1744, found 548.1753.
ASSOCIATED CONTENT
■
S
* Supporting Information
Copies of 1H, 13C, and DEPT NMR spectra for all compounds,
crystallographic data of compound 6e, and FE-SEM images of
micelles. This material is available free of charge via the Internet
at http://pubs.acs.org.
Compound 10b. This compound is prepared by the reported
procedure11 using 9b (0.400 g, 0.6 mmol) as the starting material.
1
Yield: (0.202 g, 61%); [α]D = +39.8 (c = 1.0, CHCl3); H NMR
(399.78 MHz, CDCl3) δ 1.30 (d, 3H, J = 6.4 Hz), 1.77 (td, 1H, J =
12.7, 3.8 Hz), 2.00 (s, 3H), 2.04 (s, 3H), 2.04 (m, 1H), 2.07 (s, 3H),
3.74 (s, 3H), 3.98−4.07 (m, 2H), 4.27 (dd, 1H, J = 12.0, 4.9 Hz), 4.34
(dd, 1H, J = 6.4, 2.2 Hz), 4.40 (dd, 1H, J = 9.7, 2.2 Hz), 4.88−5.00 (m,
2H), 5.15 (s, 2H), 5.15−5.29 (m, 1H), 5.48 (d, 1H, J = 9.8 Hz), 7.31−
7.43 (m, 5H); 13C NMR (100.53 MHz, CDCl3) δ 18.2, 20.6 (2C),
20.9, 35.1, 52.5, 58.5, 62.2, 67.2, 68.3, 68.5, 69.3, 76.2, 98.4, 128.1−
128.4 (5C), 136.0, 156.4, 169.8, 170.1, 170.6, 170.9; IR (CHCl3) ν
3361, 2955, 1742, 1516, 1453, 1128, 1051, 700 cm−1; HRMS (TOF)
m/z [M + Na]+ calcd for C25H33NNaO12 562.1900, found 562.1909.
Compound 11a. This compound is prepared using the above-
mentioned general procedure using 7c (0.750 g, 1 mmol) as the
starting material. Yield: (0.474 g, 73%); [α]D = +35.6 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 2.03 (s, 3H), 2.07 (s, 3H),
2.16 (s, 3H), 3.79 (s, 3H), 3.97 (s, 2H), 4.12 (d, 1H, J = 10.8 Hz), 4.20
(t, 3H, J = 9.9 Hz), 4.50 4.63 (m, 1H), 4.85 (s, 1H), 5.13 (s, 2H), 5.28
(s, 1H), 5.35 (s, 1H), 5.78 (d, 1H, J = 7.5 Hz), 7.29−7.40 (m, 5H);
13C NMR (100.53 MHz, CDCl3) δ 20.6, 20.7, 20.8, 20.9, 23.8, 52.8,
54.1, 61.9, 65.2, 67.1, 67.6, 68.9, 102.8, 128.0−128.5 (5C), 136.0,
155.8, 169.4, 169.9, 170.0, 170.5; IR (CHCl3) ν 3361, 2953, 1744,
1517, 1429, 1119, 1053, 669 cm−1; HRMS (TOF) m/z [M + Na]+
calcd for C24H30INNaO12 674.0710, found 674.0708.
Compound 11b. This compound is prepared using the above-
mentioned general procedure using 7d (0.750 g, 1 mmol) as the
starting material. Yield: (0.478 g, 72%); [α]D = +40.4 (c = 1.0,
CHCl3); 1H NMR (399.78 MHz, CDCl3) δ 1.31 (d, 3H, J = 6.4 Hz),
2.04 (s, 3H), 2.06 (s, 3H), 2.16 (s, 3H), 3.79 (s, 3H), 4.09 (d, 1H, J =
5.0 Hz), 4.11−4.15 (m, 1H), 4.20 (dd, 1H, J = 11.4, 7.2 Hz), 4.30−
4.35 (m, 1H), 4.37 (dd, 1H, J = 6.4, 2.3 Hz), 4.42 (dd, 1H, J = 9.7, 2.2
Hz), 4.79−4.84 (m, 1H), 5.14 (s, 2H), 5.30 (s, 1H), 5.35 (s, 1H), 5.46
(d, 1H, J = 9.7 Hz), 7.31−7.41 (m, 5H); 13C NMR (100.53 MHz,
CDCl3) δ 18.0, 20.6, 20.7, 20.8, 20.9, 52.7, 58.5, 62.0, 65.0, 65.3, 67.3
(2C), 77.1, 104.0, 128.1−128.5 (5C), 136.0, 156.5, 169.5, 169.9, 170.4,
170.7; IR (CHCl3) ν 3359, 2951, 1745, 1518, 1452, 1174, 1038, 702
cm−1; HRMS (TOF) m/z [M + Na]+ calcd for C25H32IN NaO12
688.0867, found 688.0861.
AUTHOR INFORMATION
Corresponding Author
*E-mail: s.hotha@iiserpune.ac.in.
Notes
■
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
S.H. thanks the DST, New Delhi for the SwarnaJayanthi
Fellowship, and M.I. thanks CSIR and N.D.T. thanks IISER
Pune for the financial support.
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=
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