Divergent total synthesis of D-ribo-phytosphingosine and L-ribo-phytosphingosine from D-ribose

Article abstract of DOI:10.1016/j.tet.2016.11.018

Divergent total synthesis of D-ribo-phytosphingosine (1) and L-ribo-phytosphingosine (2) was achieved from readily available D-ribose via cross-metathesis reaction, Wittig reaction, and diastereoselective amination reaction of allylic ethers using chlorosulfonyl isocyanate (CSI) as the key steps. As results, reactions of anti-1,2-dibenzyl ethers 11 and 16 with chlorosulfonyl isocyanate afforded exclusively anti-1,2-amino alcohols 12 and 17 with diastereoselectivity of 32:1 and 31:1 in 75% and 76% yields, respectively. These results could be explained by the neighboring group effect, leading to retention of stereochemistry.

Full text of DOI:10.1016/j.tet.2016.11.018

Accepted Manuscript
Divergent total synthesis of D-ribo-phytosphingosine and L-ribo-phytosphingosine
from D-ribose
Jong Soo Chun, Seung Min Hong, Tae Hong Jeon, Sook Jin Park, Han Pyo Son, Jun
Min Jung, Young Jae Choi, In Su Kim, Young Hoon Jung
PII:
S0040-4020(16)31162-0
10.1016/j.tet.2016.11.018
TET 28232
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 4 October 2016
Revised Date: 4 November 2016
Accepted Date: 7 November 2016
Please cite this article as: Chun JS, Hong SM, Jeon TH, Park SJ, Son HP, Jung JM, Choi YJ, Kim IS,
Jung YH, Divergent total synthesis of D-ribo-phytosphingosine and L-ribo-phytosphingosine from D-
ribose, Tetrahedron (2016), doi: 10.1016/j.tet.2016.11.018.
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Graphical Abstract
ACCEPTED MANUSCRIPT
Divergent Total Synthesis of
D-ribo-Phytosphingosine and
L-
ribo-Phytosphingosine from -Ribose
D
Jong Soo Chun, Seung Min Hong, Tae Hong Jeon, Sook Jin Park, Han Pyo Son, Jun Min
Jung, Young Jae Choi, In Su Kim, and Young Hoon Jung*
1

Divergent Total Synthesis of
D
-ribo-Phytosphingosine and -ribo-Phytosphingosine
L
ACCEPTED MANUSCRIPT
from -Ribose
D
Jong Soo Chun, Seung Min Hong, Tae Hong Jeon, Sook Jin Park, Han Pyo Son, Jun Min Jung,
Young Jae Choi, In Su Kim, and Young Hoon Jung*
School of Pharmacy, Sungkyunkwan University, Suwon 440-746, Republic of Korea
* Corresponding author. Tel.: +82-31-290-7711; fax: +82-31-292-8800; e-mail: yhjung@skku.edu
Keywords: Phytosphingosine; Amination; Chlorosulfonyl Isocyanate; Wittig reaction; Metathesis Reaction.
Abstract
Divergent total synthesis of
D
-ribo-phytosphingosine (1) and
L-ribo-phytosphingosine (2) was
achieved from readily available
D-ribose via cross-metathesis reaction, Wittig reaction, and
diastereoselective amination reaction of allylic ethers using chlorosulfonyl isocyanate (CSI) as the key
steps. As results, reactions of anti-1,2-dibenzyl ethers 11 and 16 with chlorosulfonyl isocyanate afforded
exclusively anti-1,2-amino alcohols 12 and 17 with diastereoselectivity of 32:1 and 31:1 in 75% and 76%
yields, respectively. These results could be explained by the neighboring group effect, leading to retention
of stereochemistry.
1. Introduction
Sphingolipids (4), e.g. ceramides, cerebrosides, sphingomyelins and gangliosides, have been
recognized as important elements of plasma membranes, and are composed of two nonpolar tails and one
polar head group (Figure 1). In particular, these amino alcohols are known to play significant roles in
many physiological processes such as cellular recognition, signal transduction, control of immune
response, cell adhesion and apoptosis.1 Therefore, these compounds have been the intensive subjects for
the treatment of cancers,2 diabetes,3 and diverse neurological syndromes.4 Phytosphingosines, one of the
major components of sphingolipids, have structural features involving 2-amino-1,3,4-triol subunit and
aliphatic chain. Phytosphingosines were first isolated from mushrooms in 1911.5 Since then, they have
been found to be widely distributed in plants, yeasts, fungi, and even mammalian tissues.6 In nature, the
major stereoisomer of phytosphingosines is
D-ribo-phytosphingosine (1). Unfortunately,
phytosphingosines are available only in limited amount from natural sources, and their isolation and
2

purification from natural sources are expensive and difficult. Consequently, various synthetic methods for
ACCEPTED MANUSCRIPT
preparing these compounds have received considerable attention.7,8 A common approach to synthesize
them involves the preparation of anti-1,2-amino alcohols motif from chiral starting materials, such as
carbohydrates7b,d,i and amino acids,7g,h Recently, asymmetric synthesis for the construction of their
stereogenic centers have been reported. For example, Sutherland and coworkers have described chiral
MOM ether-directed palladium(II)-catalyzed Overmann rearrangement of allylic trichloroacetimidates to
afford anti-vicinal amino alcohols.7a Bittman et al. have reported the sequential strategy, involving
asymmetric propagylation, epoxidation, and site-selective ring opening reaction, for the formation of anti-
amino alcohol motif.7e In addition, Castillόn and coworkers have disclosed the enantioselective Pd(II)-
catalyzed ring opening reaction of allylic epoxides using phthalimides to give chiral amine compounds.7f
Moreover, Jørgensen et al. have demonstrated the organocatalytic enantio- and diastereoselective one-pot
protocol to access 4,5-disubstituted isoxazoline-N-oxides via α-bromination, Henry reaction and
cyclization sequence.8b
OH
OH
OH
C13H27
OH
C13H27
OH
C13H27
OH
OH NH2
OH NH2
NH2
1
2
3
two nonpolar tails
polar head group
OH
C13H27
OR2
R1
NH
O
4
Figure 1. Structures of
D
-ribo-phytosphingosine (1),
L-ribo-phytosphingosine (2),
D-erythro-sphingosine
(3), and sphingolipids (4)
In continuation of our efforts towards asymmetric synthesis of various natural products
containing vicinal amino alcohol framework based on our amination methodology using chlorosulfonyl
isocyanate,9 herein we report the construction of
phytosphingosine (2) using commercially available -ribose through cross-metathesis and Wittig reaction
D
-ribo-phytosphingosine (1) and
L-ribo-
D
followed by stereoselective allylic amination of 1,2-anti-tribenzyl ether with chlorosulfonyl isocyanate.
2. Results and discussion
The total synthesis of
lactol 5 derived from
D
-ribo-phytosphingosine (1) was achieved by starting with benzyl-protected
D
-ribose by known procedure according to the reported literature (Scheme 1).10
3

Lactol 5 was readily oxidized to lactone 6 with acetic anhydride in DMSO.11 Lactone 6 was then
ACCEPTED MANUSCRIPT
converted into alcohol 7 by treating with N,O-dimethylhydroxylamine in the presence of
dimethylaluminum chloride.12 Swern oxidation of compound 7 and subsequent Wittig reaction afforded
olefinated intermediate 8 in 80% yield. Next, the installation of aliphatic chain of
D-ribo-
phytosphingosine (1) was achieved by cross-metathesis reaction between compound 8 and 1-tetradecene
using Hoveyda-Grubbs second generation catalyst (5 mol %) under reflux condition in dichloromethane
to afford the corresponding alkene 9 (E:Z = 7.7:1 by 1H NMR analysis) in 68% yield. Alternatively, the
olefination reaction of aldehyde compound derived from alcohol 7 using C13H27PPh3Br as a Wittig
reagent was performed to give compound 9. However, this reaction did not undergo to afford the
corresponding product 9, and all starting aldehyde was recovered. Chemoselective hydrogenation of
double bond on compound 9 afforded anti,anti-tribenzyl ether 10 in high yield (98%).
OH
OBn
OBn
MeONHMe•HCl
AlMe2Cl
HO
OH
OH
BnO
OBn
OH
BnO
OBn
O
Ac2O
ref. 11
CH2Cl2, rt
79%
76% (3 steps)
DMSO, rt
67%
O
O
O
D-ribose
5
6
i) (COCl)2, DMSO, Et3N
CH2Cl2, -78 oC
1-tetradecene
OBn O
OBn O
Hoveyda-Grubbs (ll) cat.
CH2Cl2, reflux
68%
HO
NMe
NMe
ii) MePPh3Br, NaHMDS
THF, 0 oC
OBn OBn OMe
OBn OBn OMe
7
8
80%
OBn O
OBn O
i) DIBAL, THF, -78 oC
ii) NaHMDS, BnPPh3Cl, THF, rt
92%
PtO2, H2
C13H27
NMe
C11H23
NMe
MeOH, 1 h
98%
OBn OBn OMe
OBn OBn OMe
10
9
1) CSI, Na2CO3,
toluene, 0 oC
OBn
OBn
i) O3, CH2Cl2/MeOH, -78 oC
ii) NaBH4, 0 oC
83%
C13H27
C13H27
2) sat. Na2SO3, rt
75%
OBn NHCbz
OBn OBn
12
11
OH
OBn
20% Pd(OH)2/C, H2
C13H27
OH
C13H27
OH
MeOH, rt
80%
OH NH2
OBn NHCbz
13
1
Scheme 1. Synthesis of -ribo-Phytosphingosine (1).
D
4

After DIBAL-H reduction13 of Weinreb amide 10 followed by Wittig olefination, we performed
ACCEPTED MANUSCRIPT
diastereoselective amination reaction between 1,2-anti-tribenzyl ether 11 and chlorosulfonyl isocyanate
(CSI) in toluene at 0 °C based on our previous reported conditions,9i,k and 1,2-anti-amino alcohol 12 was
exclusively formed with high regioselectivity and diastereoselectivity (anti:syn = 32:1 by HPLC analysis).
Regioselective and diastereoselective substitution of compound 12 can be explained by the neighboring
group effect, whereby the orientation of the NHCbz group retains its original configuration through
double inversion of configuration.9i,14 Finally, ozonolysis of compound 12 and subsequent reduction using
NaBH4 gave alcohol product 13, which was further hydrogenated to provide the desired product, -ribo-
D
phytosphingosine (1), in 80% yield. The spectroscopic data (1H NMR and 13C NMR) and specific rotation
of the synthesized product 1 were in full agreement with the reported values.7e
To further extend the scope of our above protocol, we envisioned the synthesis of
L-ribo-
phytosphingosine (2) from lactol 5 via an eight-step synthesis (Scheme 2). Firstly, olefination of lactol 5
with freshly prepared n-tridecyltriphenylphosphonium bromide (C13H27PPh3Br)15 in the presence of
NaHMDS provided an inseparable mixture of alkene 14 (Z:E = 8:1 by 1H NMR analysis) in 75% yield.16
Sequential hydrogenation, oxidation and Wittig reaction gave 1,2-anti-tribenzyl ether 16 (Z:E = 6.8:1 by
13
1H NMR analysis). The spectroscopic data (1H NMR and C NMR) of compound 16 were found to be
identical to those of compound 11, an enantiomeric isomer. Stereoselective amination of 16 with CSI
furnished 1,2-anti-amino alcohol 17 with high level of diastereoselectivity (anti:syn = 31:1 by HPLC
analysis) in 76% yield. Ozonolysis and subsequent reduction of compound 17 afforded compound 18 in
82% yield. Finally, both benzyl and Cbz groups were easily removed under hydrogenation conditions to
afford
L
-ribo-phytosphingosine (2) with specific rotation and spectral data (1H and 13C NMR) identical to
those reported in the literature.8b
5

Scheme 2. Synthesis of -ribo-Phytosphingosine (2)
ACCEPTEDLMANUSCRIPT
3. Conclusions
We described the total synthesis of
D-ribo-phytosphingosine and
L-ribo-phytosphingosine starting
from readily available -ribose via cross-metathesis reaction, Wittig reaction, and diastereoselective
D
amination reaction of allylic ethers using chlorosulfonyl isocyanate (CSI) as the key steps. We believe
that this synthetic protocol can be applied to the preparation of a wide range of 1,2-amino alcohol
compounds and phytosphingosine analogues.
4. Experimental Section
4.1. General
Commercially available reagents were used without additional purification, unless otherwise stated.
All reactions were performed under an inert atmosphere of nitrogen or argon. Nuclear magnetic resonance
spectra (1H and 13C NMR) were recorded on a Varian Unit 400 MHz or 500 MHz instrument with CDCl3
or CD3OD as solvent and residual CHCl3 (δ 7.26 ppm) or CH3OH (δ 3.31 ppm) as internal standard for
1H and CDCl3 (δ 77.0 ppm) or CD3OD (δ 49.0 ppm) as internal standard for 13C. Resonance patterns are
reported with the notations s (singlet), d (doublet), t (triplet), q (quartet), and m (multiplet). In addition,
the notation br is used to indicate a broad signal. Coupling constants (J) are reported in hertz (Hz). IR
spectra were recorded on a JASCO FT/IR-4600 and reported as cm-1. Optical rotations were measured
with a JASCO P1020 polarimeter and are reported as [α]ꢀꢁ (concentration g/100 mL, solvent). Thin layer
chromatography was carried out using plates coated with Kieselgel 60F254 (Merck). For flash column
chromatography, E. Merck Kieselgel 60 (230-400 mesh) was used. High-performance liquid
chromatography (HPLC) was recorded on an Agilent 1260 series. High-resolution mass spectra (HRMS)
were recorded on a JEOL JMS-700 mass spectrometer.
4.2. 3,4,5-Tri-benzyloxy-tetrahydro-pyran-2-ol (5): To a stirred solution of -ribose (10 g, 66.61 mmol)
D
in anhydrous MeOH (100 mL), thionyl chloride (1.93 mL, 26.64 mmol) was carefully added at 0 °C. The
resulting solution was refluxed for 4 h and allowed to cool at 0 °C. The resulting solution was neutralized
by the addition of solid NaHCO3 (3.92 g, 46.63 mmol) and stirred at room temperature for 1 h. The
reaction mixture was filtered and the filtrate was concentrated in vacuo. The residue was dissolved in
EtOH (100 mL), and the solution was concentrated to one half of the original volume. Then toluene (50
mL) was added and the mixture was concentrated to dryness. The residual viscous oil was used without
6

further purification in the next step. To a stirred solution of NaH (13.32 g, 333.04 mmol, 60% in mineral
ACCEPTED MANUSCRIPT
oil) in DMF (65 mL) was added droppwise a solution of methyl lyxoside from the previous step in
anhydrous THF (65 mL) over 30 min at 0 °C. After the H2 gas evolution was completed, the reaction
mixture was treated with BnBr (31.7 mL, 266.44 mmol) and then stirred for 12 h at room temperature.
The reaction mixture was carefully quenched with cold aqueous solution of 10% NH4Cl (100 mL). The
aqueous layer was extracted with EtOAc (2 x 100 mL) and the organic layer was washed with H2O (3 x
100 mL) and brine (100 mL), dried over MgSO4 and concentrated in vacuo. The residual oil (about 40 g)
was subjected to the next step without purification. Finally, the crude mixture of lyxoside from the
previous step was refluxed for 6 h with 1 M H2SO4 (88 mL), AcOH (88 mL) and 1,4-dioxane (88 mL).
The reaction mixture was cooled to 0 °C and diluted with EtOAc (220 mL) and H2O (110 mL). The
organic layer was separated and the aqueous layer was back-extracted with EtOAc (110 mL). The
combined organic layer was washed with H2O (2 x 110 mL), aqueous 5% NaHCO3 (3 x 110 mL) and
brine solution (110 mL). The combined layer was dried over MgSO4 and concentrated in vacuo. The
residue was purified by flash column chromatography (hexane/EtOAc = 6:1 to 4:1) to afford 21.18 g
(50.37 mmol, 76 % yield for 3 steps) of 5 as a colorless oil. Rf = 0.27 (hexane/EtOAc = 2:1); [α]25 –1.6 (c
D
1.0, CHCl3); IR (neat) 3435, 3029, 2294, 1736, 1693, 1455, 1093, 1051 cm-1; 1H NMR (500 MHz, CDCl3)
δ 3.40 (br s, 0.4H), 3.47–3.57 (m, 2.6H), 3.69–3.73 (m, 1H), 3.99–4.08 (m, 1H), 4.51–4.94 (m, 6H), 5.16–
13
5.20 (br, 0.4H), 5.36 (br s, 0.6H); C NMR (125 MHz, CDCl3) δ 56.49 (two carbons), 69.90, 70.33,
70.85, 71.56, 72.57, 72.75, 73.10, 73.75, 73.78, 74.69, 74.85, 75.54, 77.08, 78.03, 78.09, 81.12, 81.15,
81.32, 92.24, 96.51, 127.70, 127.73, 127.84, 127.91, 127.98, 128.05, 128.07, 128.11, 128.14, 128.17,
128.19, 128.23, 128.25, 128.39, 128.43, 128.64, 128.67, 128.71, 128.74, 128.75, 128.77, 137.78, 137.81,
137.97, 138.05, 138.11, 138.18; HRMS (CI) Calcd for C26H29O5 [M+H]+421.2015, found 421.2009.
4.3. 3,4,5-Tri-benzyloxy-tetrahydro-pyran-2-one (6): To a stirred solution of 5 (18.88 g, 44.9 mmol) in
DMSO (84 mL) was added acetic anhydride (84.34 mL, 897.98 mmol) at room temperature. After stirring
for 17 h, the reaction mixture was treated with H2O (95 mL) and extracted with EtOAc (190 mL). The
organic layer was extracted with H2O (2 x 95 mL) and brine solution (95 mL). The combined organic
layer was dried over MgSO4 and concentrated in vacuo. The residue was dissolved with isopropyl ether
(38 mL), concentrated in vacuo and again dissolved with isopropyl ether (190 mL). The solution was
stirred at room temperature for 1 h and cooled at 0 °C. The precipitate 6 as a white solid was filtered and
washed with isopropyl ether. Then the filtrate was concentrated in vacuo and purified by flash column
chromatography (hexane/EtOAc = 8:1) to afford 12.59 g (30.08 mmol, 67 % yield) of 6 as a white solid.
Rf = 0.5 (hexane/acetone = 3:1); mp = 94–96 °C; [α]25 +74.05 (c 1.02, CHCl3); IR (neat) 3027, 2873,
D
1755, 1496, 1454, 1380, 1339, 1173, 1050 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.40–7.23 (m, 15H), 5.07
7

(d, J = 12.0 Hz, 1H), 4.95 (d, J = 12.0 Hz, 1H), 4.86 (d, J = 12.0 Hz, 1H), 4.66 (d, J = 12.0 Hz, 1H), 4.50
ACCEPTED MANUSCRIPT
(d, J = 11.6 Hz, 1H), 4.47–4.40 (m, 2H), 4.27 (dd, J = 6.4, 6.0 Hz, 1H), 4.22–4.21 (m, 1H), 3.83 (d, J =
2.4 Hz, 1H), 3.80–3.75 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 169.97, 138.31, 137.62, 137.37, 128.82,
128.74, 128.46, 128.37, 128.29, 128.19, 128.10, 127.86, 127.79, 76.10, 74.32, 73.85, 73.46, 72.92, 71.79,
67.26; HRMS (EI) Calcd for C26H26O5 [M]+ 418.1780, found 418.1777.
4.4. (2R,3R,4R)-2,3,4-Tri-benzyloxy-5-hydroxy-pentanoic acid methoxy-methyl-amide (7): To a
stirred solution of N,O-dimethylhydroxyamine hydrochloride (0.47 g, 4.78 mmol) in CH2Cl2 (10 mL) was
added droppwise 1
M solution of dimethylaluminum chloride in hexane (4.8 mL, 4.78 mmol) at 0 °C. The
reaction mixure was stirred for 1 h at room temperature and cooled to 0 °C. The dissolving solution of 6
(1 g, 2.39 mmol) in CH2Cl2 (10 mL) was added droppwise to the reaction mixture. The mixture was
stirred for 1 h at room temperature, quenched with pH 8.0 phosphate buffer solution (14.4 mL) and
filtered over celite pad. The organic layer was separated, washed with brine (10 mL), dried over MgSO4
and concentrated in vacuo. The residue was purified by flash column chromatography (hexane/EtOAc =
4:1) to afford 0.91 g (1.89 mmol, 79 %) of 7 as a colorless oil. Rf = 0.2 (hexane/EtOAc = 2:1); [α]25
D
1
+37.58 (c 0.82, CHCl3); IR (neat) 3441, 3062, 3030, 2935, 2870, 1858, 1454, 1089 cm-1; H NMR (400
MHz, CDCl3) δ 7.34–7.22 (m, 15H), 4.70–4.62 (m, 4H), 4.58 (d, J = 11.2 Hz, 1H), 4.52 (d, J = 11.2 Hz,
1H), 4.43 (d, J = 11.6 Hz, 1H), 4.13–4.11 (m, 1H), 3.89–3.86 (m, 1H), 3.82–3.72 (m, 2H), 3.39 (s, 3H),
13
3.07 (s, 3H), 2.47 (br s, 1H); C NMR (100 MHz, CDCl3) δ 171.30, 138.58, 138.20, 137.40, 129.97,
128.61, 128.57, 128.51, 128.33, 128.23, 128.17, 127.98, 127.90, 80.09, 79.03, 74.39, 73.80, 72.22, 72.10,
61.74, 61.38, 32.54; HRMS (EI) calcd for C28H33NO6 [M]+ 479.2308, found 479.2309.
4.5. (2R,3R,4R)-2,3,4-Tri-benzyloxy-hex-5-enoic acid methoxy-methyl-amide (8): To a stirred solution
of oxalyl chloride (3.03 mL, 35.84 mmol) in CH2Cl2 (50 mL) was added droppwise dimethyl sulfoxide
(5.09 mL, 71.69 mmol) in CH2Cl2 (50 mL) at –78 °C. The reaction mixture was stirred for 1 h at –78 °C
and treated with 7 (11.46 g, 23.9 mmol) in CH2Cl2 (100 mL). After stirring for 1 h at same temperature,
Et3N (16.65 mL, 119.48 mmol) was added droppwise. The reaction mixture was further stirred for 0.5 h at
–78 °C, heated to 0 °C and carefully quenched with H2O (100 mL). Then the organic layer was separated,
washed with H2O (100 mL) and brine solution (100 mL), dried over MgSO4 and concentrated in vacuo.
The residual oil was used without purification in the next step. To a stirred solution of
methyltriphenylphosphonium bromide (17.07 g, 47.79 mmol) in THF (50 mL) was slowly added 1
M
sodium bis(trimethylsilyl)amide solution in THF (47.79 mL, 47.79 mmol) at 0 °C under N2 atmosphere.
The reaction mixture was stirred for 2 h at room temperature, and a solution of the former aldehyde (23.9
mmol) in THF (100 mL) was added at 0 °C. The reaction mixture was stirred for 1 h at 0 °C. After stirring
8

for 10 h at room temperature, the mixture was quenched with H2O (100 mL) and the aqueous layer was
ACCEPTED MANUSCRIPT
extracted with EtOAc (2 x 100 mL). The organic layer was washed with H2O (2 x 100 mL) and brine
(100 mL), dried over MgSO4 and concentrated in vacuo. The residue was purified by flash column
chromatography (hexane/EtOAc = 6:1) to afford 9.09 g (19.11 mmol, 80%) of 8 as a colorless oil. Rf =
0.5 (hexane/EtOAc = 2:1); [α]25 +5.77 (c 1.17, CHCl3); IR (neat) 3441, 3063, 3029, 2937, 2866, 1663,
D
1
1454, 1071 cm-1; H NMR (400 MHz, CDCl3) δ 7.33–7.20 (m, 15H), 5.98–5.89 (m, 1H), 5.26 (dd, J =
10.4, 2.0 Hz, 1H), 5.02 (dd, J = 17.2, 1.2 Hz, 1H), 4.82 (d, J = 11.2 Hz, 1H), 4.63–4.58 (m, 2H), 4.53 (d, J
= 11.2 Hz, 1H), 4.43–4.40 (m 2H), 4.33 (d, J = 11.6 Hz, 1H), 4.16–4.11 (m, 2H), 3.41 (s, 3H), 3.40 (s,
13
3H); C NMR (100 MHz, CDCl3) δ 138.96, 137.63, 134.94, 128.52, 128.48, 128.45, 128.28, 128.25,
128.03, 127.77, 127.59, 127.51, 119.65, 81.69, 74.87, 73.68, 71.99, 70.49, 61.47, 32.29; HRMS (EI)
calcd for C29H33NO5 [M]+ 475.2359, found 475.2357.
4.6. (2R,3R,4R)-2,3,4-Tri-benzyloxy-octadec-5-enoic acid methoxy-methyl-amide (9): To a stirred
solution of 8 (0.48 g, 1 mmol) in CH2Cl2 (15 mL) was added Hoveyda-Grubbs 2nd generation catalyst
(0.031 g, 0.05 mmol) and 1-tetradecene (0.55 mL, 2 mmol). The reaction mixture was refluxed for 20 h,
cooled to room temperature and filtered through a pad of celite. The filtrate was concentrated in vacuo
and the residue was purified by flash column chromatography (hexane/EtOAc = 10:1) to afford 0.44 g
(0.68 mmol, 68%) of 9 as a colorless oil. Rf = 0.4 (hexane/EtOAc = 3:1); [α]25 +3.14 (c 0.9, CHCl3); IR
D
(neat) 3063, 3030, 2921, 2854, 1667, 1454, 1091 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.35–7.22 (m, 15H),
5.55 (dd, J = 15.6, 8.8 Hz, 1H), 5.39–5.33 (m,1H), 4.83 (d, J = 11.2 Hz, 1H), 4.62–4.52 (m, 4H), 4.38 (d,
J = 12 Hz, 1H), 4.31 (d, J = 12 Hz, 1H), 4.12 (dd, J = 8.8, 2.0 Hz, 1H), 4.05 (dd, J = 8.8, 2.0 Hz, 1H),
3.42 (s, 3H), 3.11 (s, 3H), 2.03–1.99 (m, 2H), 1.29–1.19 (m, 20H), 0.88 (t, J = 6.0, 7.2 Hz, 3H); 13C NMR
(100 MHz, CDCl3) δ 138.91, 138.79, 137.37, 137.16, 128.46, 128.38, 128.23, 128.19, 128.05, 127.99,
127.79, 127.54, 127.50, 127.32, 127.19, 126.92, 125.80, 81.58, 81.06, 74.72, 73.27, 71.72, 69.76, 61.19,
32.48, 31.91, 29.70, 29.65, 29.63, 29.54, 29.37, 29.28, 29.25, 22.69, 14.14; HRMS (EI) calcd for
C41H57NO5 [M]+ 643.4237, found 643.4235.
4.7. (2R,3R,4R)-2,3,4-Tri-benzyloxy-octadecanoic acid methoxy-methyl-amide (10): To a stirred
solution of 9 (0.37 g, 0.57 mmol) in MeOH (4 mL) was added platinum (IV) oxide (7 mg, 0.03 mmol).
The reaction mixture was degassed, stirred for 1 h under H2 atmosphere and filtered through a pad of
celite. The filtrate was concentrated in vacuo and the residue was purified by flash column
chromatography (hexane/EtOAc = 9:1) to afford 0.36 g (0.56 mmol, 98%) of 10 as a colorless oil. Rf =
0.4 (hexane/EtOAc = 3:1); [α]25 +97.23 (c 1.03, CHCl3); IR (neat) 3063, 3030, 2921, 2852, 1667, 1454,
D
1092 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.36–7.21 (m, 15H), 4.73 (t, J = 10.8, 11.6 Hz, 2H), 4.64 (d, J
9

= 12.4 Hz, 1H), 4.49 (dd, J = 10.8, 11.6 Hz, 3H), 4.36 (d, J = 12.0 Hz, 1H), 4.12 (d, J = 8.4 Hz, 1H), 3.68
ACCEPTED MANUSCRIPT
(d, J = 8.8 Hz, 1H), 3.45 (s, 3H), 3.15 (s, 3H), 1.69–1.65 (m, 1H), 1.42–1.38 (m, 1H), 1.32–1.22 (m, 24H),
13
0.88 (t, J = 6.0, 7.2 Hz, 3H); C NMR (100 MHz, CDCl3) δ 138.70, 138.50, 137.29, 128.49, 128.29,
128.27, 128.21, 128.11, 128.07, 128.03, 127.87, 127.51, 127.43, 126.93, 79.85, 79.35, 74.21, 73.06, 71.73,
71.57, 61.17, 31.93, 29.73, 29.70, 29.68, 29.47, 29.38, 26.02, 22.71, 14.15; HRMS (EI) calcd for
C41H59NO5 [M]+ 645.4393, found 645.4387.
4.8. (3S,4R,5R)-3,4,5-Tri-benzyloxy-1-phenylnonadec-1-ene (11): To a solution of 10 (3.66 g, 5.59
mmol) in THF (30 mL) at –78 °C was added DIBAL-H (22.35 mL, 22.35 mmol, 1
M solution in THF).
The reaction mixture was stirred for 0.5 h at –78 °C, quenched with 0.5 tartaric acid (112 mL) at 0 °C
M
and further stirred for 0.5 h. The aqueous layer was extracted with CH2Cl2 (2 x 100 mL). The organic
layer was washed with H2O (100 mL) and brine (100 mL), dried over MgSO4 and concentrated in vacuo.
The residual oil was used without purification in the next step. To a stirred solution of
benzyltriphenylphosphonium chloride (3.26 g, 8.38 mmol) in THF (30 mL) was slowly added sodium
bis(trimethylsilyl)amide solution (8.38 mL, 8.38 mmol, 1
M solution in THF) at 0 °C under N2
atmosphere. The reaction mixture was stirred for 2 h at room temperature, and a solution of the former
aldehyde (5.59 mmol) in THF (30 mL) was added droppwise at 0 °C. The reaction mixture was stirred for
0.5 h at 0 °C. After stirring for 2 h at room temperature, the mixture was quenched with H2O (60 mL) and
the aqueous layer was extracted with EtOAc (2 x 100 mL). The organic layer was washed with H2O (2 x
100 mL) and brine (100 mL), dried over MgSO4 and concentrated in vacuo. The residue was purified by
flash column chromatography (hexane/EtOAc = 50:1) to afford 3.39 g (5.14 mmol, 92%, Z:E = 6.4:1) of
11 as a colorless oil. Rf = 0.5 (hexane/EtOAc = 19:1); [α]25 +87.95 (c 1.0, CHCl3); IR (neat) 3062, 3029,
D
1
2922, 2852, 1495, 1454, 1089, 1063, 1027 cm-1; Z-isomer: H NMR (400 MHz, CDCl3) δ 7.38–6.99 (m,
20H), 6.88 (d, J = 12.0 Hz, 1H), 5.75 (dd, J = 12.0, 10.4 Hz, 1H), 4.78 (s, 2H), 4.51–4.46 (m, 2H), 4.39
(s, 2H), 4.12 (d, J = 11.6 Hz, 1H), 3.85 (dd, J = 8.4, 3.6 Hz, 1H), 3.61–3.59 (m, 1H), 1.69–1.64 (m, 1H),
13
1.42–1.37 (m, 1H), 1.26–1.13 (m, 24H), 0.88 (t, J = 6.0, 7.2 Hz, 3H); C NMR (100 MHz, CDCl3) δ
138.90, 138.74, 137.97, 136.74, 134.38, 130.26, 128.94, 128.30, 128.23, 128.17, 128.14, 128.10, 127.96,
127.85, 127.40, 127.32, 127.27, 127.09, 80.33, 79.62, 73.88, 73.44, 71.22, 69.74, 31.93, 29.81, 29.72,
29.68, 29.38, 29.28, 25.56, 22.70, 14.15; HRMS (EI) calcd for C46H60O3 [M]+ 660.4542, found 660.4538.
4.9. (2S,3S,4R)-(2,3-Bis-benzyloxy-1-styryl-heptadecyl)-carbamic acid benzyl ester (12): To a stirred
solution of 11 (3.15 g, 4.77 mmol) and Na2CO3 (6.06 g, 57.19 mmol) in anhydrous toluene (24 mL) was
added droppwise chlorosulfonyl isocyanate (3.32 mL, 38.13 mmol) at –20 °C under N2 atmosphere. The
reaction mixture was stirred for 24 h at 0 °C and quenched with aqueous 5% NaCl (30 mL). The aqueous
10

layer was extracted with EtOAc (2 x 10 mL). The organic layer was added to a saturated solution of
ACCEPTED MANUSCRIPT
Na2SO3 (20 mL), and the reaction mixture was stirred for 24 h at room temperature. The organic layer
was separated, washed with H2O (20 mL) and brine (20 mL), dried over MgSO4, and concentrated in
vacuo. The residue was purified by flash column chromatography (hexane/EtOAc = 15:1) to afford 2.52 g
(3.57 mmol, 75%, Z:E = 8:1, anti:syn = 32:1) of 12 as a white solid. Rf = 0.2 (hexane/EtOAc = 14:1); mp
= 54–56 °C; [α]25 –52.66 (c 1.03, CHCl3); IR (neat) 3338, 3062, 3029, 2932, 2852, 1707, 1495, 1454,
D
1
1213, 1060, 1027 cm-1; Z-isomer: H NMR (400 MHz, CDCl3) δ 7.38–7.12 (m, 20H), 6.58 (d, J = 12.0
Hz, 1H), 5.79 (t, J = 10.4, 10.8 Hz, 1H), 5.19 (d, J = 8.4 Hz, 1H), 5.10–5.04 (m, 3H), 4.62 (d, J = 11.6 Hz,
1H), 4.54 (d, J = 9.2 Hz, 1H), 4.32 (d, J = 11.6 Hz, 1H), 4.23 (d, J = 11.6 Hz, 1H), 3.69 (br s, 1H), 3.40 (d,
13
J = 4.0 Hz, 1H), 1.69–1.59 (m, 2H), 1.26–1.22 (m, 24H), 0.88 (t, J = 6.0, 7.2 Hz, 3H); C NMR (100
MHz, CDCl3) δ 155.42, 138.21, 136.33, 132.27, 128.59, 128.52, 128.45, 128.39, 128.36, 128.19, 127.98,
127.81, 127.71, 127.58, 127.38, 127.27, 126.46, 81.67, 79.93, 73.75, 71.71, 66.56, 50.33, 31.92, 30.47,
29.79, 29.71, 29.67, 29.62, 29.37, 25.26, 22.70, 14.15; HRMS (EI) calcd for C47H61NO4 [M]+ 703.4601,
found 703.4600; HPLC (Chiralpak AD column, n-hexane:i-PrOH = 90:10, 0.3 mL/min, 254 nm) Rt
(minor) = 6.17 min, Rt (major) = 6.76 min, dr = 32:1.
4.10. (2S,3S,4R)-(2,3-Bis-benzyloxy-1-hydroxymethyl-heptadecyl)-carbamic acid benzyl ester (13):
Compound 12 (2.28 g, 3.24 mmol) was dissolved with CH2Cl2 (32 mL) and MeOH (32 mL). The solution
was bubbled with ozone for 1 h at –78 °C, flushed with argon gas for 1 h, and slowly treated with NaBH4
(1.22 g, 32.39 mmol) at the same temperature. The reaction mixture was stirred for 3 h at 0 °C, quenched
with a saturated solution of NH4Cl (30 mL), and extracted with CH2Cl2 (2 x 30 mL). The organic layer
was separated, washed with H2O (20 mL) and brine (20 mL), dried over MgSO4, and concentrated in
vacuo. The residue was purified by flash column chromatography (hexane/EtOAc = 7:1) to afford 1.71 g
(2.7 mmol, 83%) of 13 as a colorless oil. Rf = 0.3 (hexane/EtOAc 3:1); [α]25 –26.23 (c 0.96, CHCl3); IR
D
1
(neat) 3392, 3064, 3031, 2961, 2923, 2852, 1705, 1454, 1262, 1213, 1102, 1060, 1027 cm-1; H NMR
(400 MHz, CDCl3) δ 7.44–7.28 (m, 15H), 5.46 (d, J = 8.4 Hz, 1H), 5.05 (s, 2H), 4.69 (d, J = 11.6 Hz, 1H),
4.61 (d, J = 11.6 Hz, 1H), 4.51 (t, J = 14.8, 11.6 Hz, 2H), 3.93–3.90 (m, 2H), 3.74 (s, 1H), 3.65–3.64 (m,
2H), 2.99 (br s, 1H), 1.68–1.60 (m, 2H), 1.42–1.27 (m, 24H), 0.88 (t, J = 6.0, 7.2 Hz, 3H); 13C NMR (100
MHz, CDCl3) δ 156.01, 138.12, 137.81, 136.53, 129.64, 128.55, 128.52, 128.46, 128.39, 128.06, 127.98,
127.95, 127.74, 81.55, 78.95, 73.28, 72.57, 66.65, 62.49, 52.50, 31.92, 30.45, 29.71, 29.67, 29.63, 29.60,
29.46, 29.37, 25.88, 22.69, 14.14; HRMS (EI) calcd for C40H57NO5 [M]+ 631.4237, found 631.4241.
4.11. -ribo-Phytosphingosine (1): A solution of 13 (0.4 g, 0.63 mmol) and 20% palladium hydroxide on
D
carbon (0.2 g, 50% w/w) in MeOH (6 mL) was shaken for 2 day under 50-psi hydrogen pressure using
11

Parr hydrogenator. The reaction mixture was filtered through a pad of celite and concentrated in vacuo.
ACCEPTED MANUSCRIPT
The residue was treated with EtOAc (10 mL), refluxed for 1 h, and cooled to 0 °C. The precipitate 1 as a
white solid was filtered and washed with EtOAc. Then the filtrate was concentrated in vacuo and purified
by flash column chromatography (CH2Cl2/MeOH/NH4OH = 80:20:1) to afford 0.16g (0.51 mmol, 80%)
of 1 as a white solid. Rf = 0.10 (CH2Cl2/MeOH/HCO2H = 85:15:0.2); mp = 98–101 °C [lit.7e mp = 99–
101 °C]; [α]2D5 +8.91 (c 0.87, pyridine) [lit.7e [α]2D5 +8.0 (c 0.8, pyridine)]; IR (neat) 3385, 3064, 3031, 2962,
1
2917, 2848, 1455, 1262, 1103, 1063, 1032 cm-1; H NMR (400 MHz, CD3OD) δ 3.78 (dd, J = 10.8, 4.0
Hz, 1H), 3.61–3.54 (m, 2H), 3.39–3.34 (m, 1H), 2.99–2.95 (m, 1H), 1.80–1.75 (m, 1H), 1.60–1.58 (m,
13
1H), 1.32 (m, 24H), 0.93 (t, J = 6.4, 6.8 Hz, 3H); C NMR (100 MHz, CD3OD) δ 76.55, 74.48, 64.29,
55.83, 34.75, 33.07, 30.95, 30.81, 30.77, 30.48, 26.62, 23.74, 14.46; HRMS (EI) calcd for C18H39NO3
[M]+ 317.2930, found 317.2928.
4.12. (2R,3S,4S)-(2,3,4-Tri-benzyloxy-octadec-5-en-1-ol (14): A mixture of 1-bromotridecane (3.33 g,
12.66 mmol) and triphenylphosphine (3.32 g, 12.66 mmol) was heated at 140 °C under N2 atmosphere for
5 h. The reaction mixture was cooled to 60 °C, and the formed solid gel was dissolved with THF (30 mL).
To a solution of C13H27PPh3Br in THF at 0 °C was added droppwise sodium bis(trimethylsilyl)amide
solution (12.66 mL, 12.66 mmol, 1
M solution in THF). The reaction mixture was stirred at 0 °C for 1.5 h
and cooled to –78 °C. To a stirred solution was added a solution of 5 (2.66 g, 6.33 mmol) in THF (20 mL)
for 0.5 h under N2 atmosphere at –78 °C. The reaction mixture was stirred at –78 °C for 0.5 h, and then at
room temperature for 10 h. The mixture was quenched with a saturated solution of NH4Cl (40 mL), and
extracted with EtOAc (2 x 50 mL). The organic layer was washed with H2O (40 mL) and brine (40 mL),
dried over MgSO4, and concentrated in vacuo. The residue was purified by flash column chromatography
(hexane/EtOAc = 10:1) to afford 2.78 g (4.74 mmol, 75%) of alkene 14 (Z:E = 8:1 by 1H NMR analysis),
as a colorless oil. Rf = 0.40 (hexane/EtOAc = 5:1); [α]25 +34.65 (c 1.13, CHCl3); IR (neat) 3367, 3064,
D
3031, 2961, 2923, 2852, 1454, 1262, 1101, 1063, 1028 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.31–7.24 (m,
15H), 5.76–5.70 (m, 1H), 5.50 (t, J = 10.4, 10.0 Hz, 1H), 4.81–4.69 (m, 2H), 4.59 (dd, J = 12.0, 11.6 Hz,
2H), 4.49–4.45 (m, 2H), 4.35 (d, J = 12.4 Hz, 1H), 3.85 (t, J = 5.2, 4.4 Hz, 1H), 3.84–3.80 (m, 2H), 3.61–
13
3.58 (m, 1H), 2.56 (br s, 1H), 2.00–1.85 (m, 2H), 1.25–1.19 (m, 20H), 0.88 (t, J = 5.6, 7.2 Hz, 3H); C
NMR (100 MHz, CDCl3) δ 138.46, 138.39, 138.21, 136.16, 128.39, 128.36, 128.29, 128.09, 127.66,
127.62, 127.58, 127.46, 127.44, 126.27, 81.34, 79.21, 74.58, 74.16, 71.56, 70.01, 61.02, 31.92, 29.70,
29.66, 29.61, 29.51, 29.43, 29.36, 28.07, 22.69, 14.14; HRMS (EI) calcd for C39H54O4 [M]+ 586.4022,
found 586.4018.
4.13. (2R,3S,4S)-(2,3,4-Tri-benzyloxy-octadecan-1-ol (15): To a stirred solution of 14 (0.84 g, 1.43
12

mmol) in MeOH (7 mL) was added platinum (IV) oxide (16 mg, 0.071 mmol) at room temperature. The
ACCEPTED MANUSCRIPT
reaction mixture was degassed, stirred for 1 h under H2 atmosphere and filtered through a pad of celite.
The filtrate was concentrated in vacuo and the residue was purified by flash column chromatography
(hexane/EtOAc = 10:1) to afford 0.8 g (1.36 mmol, 95%) of 15 as colorless oil. Rf = 0.3 (hexane/EtOAc =
5:1); [α]25 –2.72 (c 1.16, CHCl3); IR (neat) 3393, 3064, 3031, 2961, 2922, 2852, 1454, 1262, 1099, 1063,
D
1028 cm-1; 1H NMR (400 MHz, CDCl3) δ 7.33–7.21 (m, 15H), 4.77 (d, J = 11.6 Hz, 1H), 4.70 (d, J = 11.2
Hz, 1H), 4.62 (t, J = 11.2, 9.6 Hz, 2H), 4.51 (d, J = 3.6 Hz, 1H), 4.48 (d, J = 2.4 Hz, 1H), 3.86–3.81 (m,
3H), 3.63–3.61 (m, 1H), 3.59–3.55 (m, 1H), 2.54 (br s, 1H), 1.65–1.63 (m, 1H), 1.44–1.41 (m, 1H), 1.26
13
(m, 24H), 0.88 (t, J = 6.0, 7.2 Hz, 3H); C NMR (100 MHz, CDCl3) δ 138.37, 138.23, 137.87, 128.45,
128.40, 128.32, 128.10, 128.01, 127.85, 127.75, 127.61, 79.90, 79.46, 78.51, 73.79, 72.04, 71.80, 61.27,
31.93, 30.03, 29.75, 29.71, 29.67, 29.65, 29.38, 25.73, 22.70, 14.15; HRMS (EI) calcd for C39H56O4 [M]+
588.4179, found 588.4174.
4.14. (3R,4S,5S)-3,4,5-Tri-benzyloxy-1-phenylnonadec-1-ene (16): To a stirred solution of oxalyl
chloride (0.18 mL, 2.13 mmol) in CH2Cl2 (3 mL) was added dropwise dimethyl sulfoxide (0.3 mL, 4.25
mmol) in CH2Cl2 (3 mL) at –78 °C. The reaction mixture was stirred for 1 h at –78 °C and treated with 15
(0.83 g, 1.42 mmol) in CH2Cl2 (7 mL). After stirring for 1 h at same temperature, Et3N (0.99 mL, 7.09
mmol) was added droppwise. The reaction mixture was further stirred for 0.5 h at –78 °C, heated to 0 °C
and carefully quenched with H2O (10 mL). Then, the organic layer was separated, washed with H2O (10
mL) and brine (10 mL), dried over MgSO4 and concentrated in vacuo. The residual oil was used without
purification in the next step. To a stirred solution of benzyltriphenylphosphonium chloride (0.83 g, 2.13
mmol) in THF (6 mL) was slowly added sodium bis(trimethylsilyl)amide solution (2.13 mL, 2.13 mmol,
1
M solution in THF) at 0 °C under N2 atmosphere. The reaction mixture was stirred for 2 h at room
temperature, and a solution of the former aldehyde (1.42 mmol) in THF (6 mL) was added droppwise at
0 °C. The reaction mixture was stirred for 0.5 h at 0 °C. After stirring for 2 h at room temperature, the
mixture was quenched with H2O (7 mL) and the aqueous layer was extracted with EtOAc (2 x 14 mL).
The organic layer was washed with H2O (10 mL) and brine (10 mL), dried over MgSO4 and concentrated
in vacuo. The residue was purified by flash column chromatography (hexane/EtOAc = 60:1) to afford
0.84 g (1.27 mmol, 90%, Z:E = 6.8:1) of 16 as colorless oil. Rf = 0.5 (hexane/EtOAc = 19:1); [α]25 –
D
98.62 (c 1.07, CHCl3); IR (neat) 3063, 3031, 2922, 2852, 1496, 1454, 1100, 1062, 1027 cm-1; Z-isomer:
1H NMR (400 MHz, CDCl3) δ 7.37–6.99 (m, 20H), 6.89 (d, J = 11.6 Hz, 1H), 5.75 (t, J = 11.2, 10.4 Hz,
1H), 4.78 (s, 2H), 4.50–4.47 (m, 2H), 4.39 (s, 2H), 4.12 (d, J = 11.6 Hz, 1H), 3.85 (dd, J = 6.4, 3.6 Hz,
1H), 3.61–3.59 (m, 1H), 1.69–1.64 (m, 1H), 1.42–1.37 (m, 1H), 1.26–1.13 (m, 24H), 0.88 (t, J = 6.4, 7.2
Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 138.96, 138.82, 138.06, 136.78, 134.35, 130.31, 128.96, 128.31,
13

128.17, 128.13, 128.10, 127.95, 127.86, 127.84, 127.40, 127.31, 127.27, 127.10, 80.52, 79.69, 73.91,
ACCEPTED MANUSCRIPT
73.57, 71.27, 69.79, 31.94, 29.83, 29.73, 29.72, 29.69, 29.38, 29.36, 25.59, 22.70, 14.14; HRMS (EI)
calcd for C46H60O3 [M]+ 660.4542, found 660.4542.
4.15. (2R,3R,4S)-(2,3-Bis-benzyloxy-1-styryl-heptadecyl)-carbamic acid benzyl ester (17): To a
stirred solution of 16 (0.8 g, 1.21 mmol) and Na2CO3 (1.54 g, 14.52 mmol) in anhydrous toluene (6 mL)
was added droppwise chlorosulfonyl isocyanate (0.84 mL, 9.68 mmol) at –20 °C under N2 atmosphere.
The reaction mixture was stirred for 24 h at 0 °C and quenched with aqueous 5% NaCl (6 mL). The
aqueous layer was extracted with EtOAc (2 x 3 mL). The organic layer was added to a saturated solution
of Na2SO3 (5 mL), and the reaction mixture was stirred for 24 h at room temperature. The organic layer
was separated, washed with H2O (5 mL) and brine (5 mL), dried over MgSO4, and concentrated in vacuo.
The residue was purified by flash column chromatography (hexane/EtOAc = 15:1) to afford 0.65 g (0.92
mmol, 76%, Z:E = 7.7:1, anti:syn = 31:1) of 17 as a white solid. Rf = 0.2 (hexane/EtOAc = 14:1); mp =
54–56 °C; [α]25 +59.98 (c 1.11, CHCl3); IR (neat) 3365, 3064, 3031, 2962, 2918, 2849, 1697, 1517, 1453,
D
1
1261, 1104, 1063, 1027 cm-1; Z-isomer: H NMR (400 MHz, CDCl3) δ 7.36–7.12 (m, 20H), 6.59 (d, J =
12.0 Hz, 1H), 5.79 (t, J = 10.0, 11.6 Hz, 1H), 5.18 (d, J = 8.0 Hz, 1H), 5.10–5.04 (m, 3H), 4.61 (d, J =
12.0 Hz, 1H), 4.55–4.52 (m, 1H), 4.32 (d, J = 11.2 Hz, 1H), 4.23 (d, J = 11.2 Hz, 1H), 3.68 (br s, 1H),
3.40 (d, J = 4.0 Hz, 1H), 1.68–1.54 (m, 2H), 1.25–1.21 (m, 24H), 0.88 (t, J = 6.8, 6.8 Hz, 3H); 13C NMR
(100 MHz, CDCl3) δ 155.40, 138.29, 136.37, 132.25, 128.59, 128.49, 128.42, 128.36, 128.33, 128.17,
127.95, 127.91, 127.80, 127.77, 127.66, 127.55, 127.34, 127.24, 126.46, 81.74, 80.00, 73.75, 71.72, 66.52,
50.38, 31.92, 30.49, 29.77, 29.70, 29.66, 29.61, 29.59, 29.36, 25.28, 22.69, 14.14; HRMS (EI) calcd for
C47H61NO4 [M]+ 703.4601, found 703.4600; HPLC (Chiralpak AD column, n-hexane:i-PrOH = 90:10,
0.3 mL/min, 254 nm) Rt (minor) = 6.98 min, Rt (major) = 7.55 min, dr = 31:1.
4.16. (2R,3R,4S)-(2,3-Bis-benzyloxy-1-hydroxymethyl-heptadecyl)-carbamic acid benzyl ester (18):
Compound 17 (5.8 g, 8.24 mmol) was dissolved with CH2Cl2 (80 mL) and MeOH (80 mL). The solution
was bubbled with ozone for 1 h at –78 °C, flushed with argon gas for 1 h, and slowly treated with NaBH4
(3.12 g, 82.39 mmol) at the same temperature. The reaction mixture was stirred for 3 h at 0 °C, quenched
with a saturated solution of NH4Cl (80 mL), and extracted with CH2Cl2 (2 x 80 mL). The organic layer
was separated, washed with H2O (80 mL) and brine (80 mL), dried over MgSO4, and concentrated in
vacuo. The residue was purified by flash column chromatography (hexane/EtOAc = 7:1) to afford 4.27 g
(6.76 mmol, 82%) of 18 as a colorless oil. Rf = 0.3 (hexane/EtOAc = 3:1); [α]25 +28.66 (c 1.16, CHCl3);
D
IR (neat) 3367, 3064, 3031, 2961, 2923, 2862, 1706, 1454, 1262, 1213, 1106, 1061, 1027 cm-1; 1H NMR
(400 MHz, CDCl3) δ 7.44–7.26 (m, 15H), 5.44 (d, J = 8.8 Hz, 1H), 5.05 (s, 2H), 4.69 (d, J = 11.6 Hz, 1H),
14

4.61 (d, J = 11.2 Hz, 1H), 4.56–4.48 (m, 2H), 3.92–3.89 (m, 2H), 3.74 (s, 1H), 3.66–3.65 (m, 2H), 2.95
ACCEPTED MANUSCRIPT
13
(br s, 1H), 1.61–1.60 (m, 2H), 1.42–1.27 (m, 24H), 0.88 (t, J = 6.0, 7.2 Hz, 3H); C NMR (100 MHz,
CDCl3) δ 156.00, 138.11, 137.78, 136.52, 129.65, 128.57, 128.54, 128.47, 128.40, 128.07, 128.00, 127.95,
127.75, 81.68, 78.92, 73.28, 72.61, 66.67, 62.53, 52.47, 31.93, 30.49, 29.71, 29.67, 29.63, 29.60, 29.56,
29.46, 29.37, 25.89, 22.69, 14.14; HRMS (EI) calcd for C40H57NO5 [M]+ 631.4237, found 631.4242.
4.17. -ribo-Phytosphingosine (2): A solution of compound 18 (3.0 g, 4.75 mmol) and 20% palladium
L
hydroxide on carbon (1.5 g, 50% w/w) in MeOH (50 mL) was shaken for 3 day under 50-psi hydrogen
pressure using Parr hydrogenator. The reaction mixture was filtered through a pad of celite and
concentrated in vacuo. The residue was treated with EtOAc (70 mL), refluxed for 1 h, and cooled to 0 °C.
The precipitate 2 as a white solid was filtered and washed with EtOAc. Then the filtrate was concentrated
in vacuo and purified by flash column chromatography (CH2Cl2/MeOH/NH4OH = 80:20:1) to afford
1.24g (3.9 mmol, 82%) of 2 as a white solid. Rf = 0.1 (CH2Cl2/MeOH/HCO2H = 85:15:0.2); mp = 99–
102 °C [lit.8b mp = 99–101 °C]; [α]2D5 –8.21 (c 0.8, pyridine) [lit.8b [α]2D5 –7.7 (c 0.74, pyridine)]; IR (neat)
3365, 3064, 3031, 2962, 2917, 2848, 1455, 1262, 1103, 1063, 1032 cm-1; 1H NMR (400 MHz, CD3OD) δ
3.78 (dd, J = 10.8, 4.0 Hz, 1H), 3.61–3.54 (m, 2H), 3.39–3.34 (m, 1H), 2.99–2.95 (m, 1H), 1.80–1.75 (m,
13
1H), 1.60–1.58 (m, 1H), 1.32 (m, 24H), 0.93 (t, J = 6.4, 7.2 Hz, 3H); C NMR (100 MHz, CD3OD) δ
76.55, 74.48, 64.29, 55.83, 34.75, 33.07, 30.95, 30.81, 30.77, 30.48, 26.62, 23.74, 14.46; HRMS (EI)
calcd for C18H39NO3 [M]+ 317.2930, found 317.2932.
Acknowledgment
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the
Korea government (MSIP) (No. 2016R1D1A1B03932216).
Supplementary data
Supplementary data available: 1H NMR and 13C NMR copies of all compounds. Supplementary data
associated with this article can be found in the online version, at http://
References and notes
1. (a) Riethmüller, J.; Riehle, A.; Grassmé, H.; Gulbins, E. Biochim. Biophys. Acta, Biomembr. 2006,
1758, 2139; (b) Snook, C. F.; Jones, J. A.; Hannun, Y. A. Biochim. Biophys. Acta, Mol. Cell Biol.
Lipids 2006, 1761, 927.
2. Modrak, D. E.; Gold, D. V.; Goldenberg, D. M. Mol. Cancer Ther. 2006, 5, 200.
15

3. Summers, S. A.; Nelson, D. H. Diabetes 2005, 54, 591.
ACCEPTED MANUSCRIPT
4. Kolter, T.; Sandhoff, K. Biochim. Biophys. Acta, Biomembr. 2006, 1758, 2057.
5. Zellner, J. Monatsh. Chem. 1911, 32, 133.
6. (a) Karlsson, K. A.; Martensson, E. Biochim. Biophys. Acta 1968, 152, 230; (b) Carter, H. E.;
Hirschberg, C. B. Biochemistry 1968, 7, 2296.
7. For -ribo-phytosphingosine, see: (a) Calder, E. D. D.; Zaed, A. M.; Sutherland, A. J. Org. Chem.
D
2013, 78, 7223; (b) Yen, Y.-F.; Sawant, R. C; Luo, S.-Y. Synthesis, 2013, 45, 511; (c) Devi, T. J.;
Saikia, B.; Barua, N. C. Tetrahedron 2013, 69, 3817; (d) Perali, R. S.; Mandava, S.; Chalapala, S.
Tetrahedron 2011, 67, 9283; (e) Liu, Z.; Byun, H.-S.; Bittman, R. J. Org. Chem. 2010, 75, 4356; (f)
Llaveria, J.; Díaz, Y.; Matheu, I.; Castillón, S. Org. Lett. 2009, 11, 205; (g) Park, J.-J.; Lee, J. H.; Li,
Q.; Diaz, K.; Chang, Y.-T.; Chung, S.-K. Bioorg. Chem. 2008, 36, 220; (h) Lombardo, M.; Capdevila,
M. G.; Pasi, F.; Trombini, C. Org. Lett. 2006, 8, 3303; (i) Chiu, H.-Y.; Tzou, D.-L. M.; Patkar, L. N.;
Lin, C.-C. J. Org. Chem. 2003, 68, 5788; (j) He, L.; Byun, H.-S.; Bittman, R. J. Org. Chem. 2000, 65,
7618.
8. For -ribo-phytosphingosine, see: (a) Jang, K. H.; Lee, Y. Y.; Sim, C. J.; Oh, K. B.; Shin, J. h. Bioorg.
L
Med. Chem. Lett. 2012, 22, 1078; (b) Jiang, H.; Elsner, P.; Jensen, K. L.; Falcicchio, A.; Marcos, V.;
Jørgensen, K. A. Angew. Chem., Int. Ed. 2009, 48, 6844.
9. (a) Jung, Y. H.; Kim, S. I.; Hong, Y. J.; Park, S. J.; Kang, K. T.; Kim, S. Y.; Kim I. S. Tetrahedron
2015, 71, 1068; (b) Li, Q. R.; Kim, S. I.; Park, S. J.; Hong, Y. R.; Yang, H. R.; Baek, A. R.; Kim, I. S.;
Jung, Y. H. Tetrahedron 2013, 69, 10384; (c) Li, Q. R.; Dong, G. R.; Park, S. J.; Hong, Y. R.; Kim, I.
S.; Jung, Y. H. Eur. J. Org. Chem. 2013, 4427; (d) Min, I. S.; Kim, S. I.; Hong, S.; Kim, I. S.; Jung, Y.
H. Tetrahedron 2013, 69, 3901; (e) Lee, S. H.; Park, S. J.; Kim, I. S.; Jung, Y. H. Tetrahedron 2013,
69, 1877; (f) Dong, G. R.; Hong, S. M.; Kim, S. I.; Kim, I. S.; Jung, Y. H. Eur. J. Org. Chem. 2012,
4200; (g) Kim, I. S.; Jung, Y. H. Heterocycles 2011, 83, 2489; (h) Lee, S. H.; Kim, I. S.; Li, Q. R.;
Dong, G. R.; Jeong, L. S.; Jung, Y. H. J. Org. Chem. 2011, 76, 10011; (i) Kim, I. S.; Li, Q. R.; Dong,
G. R.; Kim, Y. C.; Hong, Y. J.; Lee, M.; Chi, K.-W.; Oh, J. S.; Jung, Y. H. Eur. J. Org. Chem. 2010,
1569; (j) Kim, I. S.; Kim, S. J.; Lee, J. K.; Li, Q. R.; Jung, Y. H. Carbohydrate Research 2007, 342,
1502; (k) Kim, I. S.; Zee, O. P.; Jung, Y. H. Org. Lett. 2006, 8, 4101; (l) Kim, J. D.; Han, G.; Jeong, L.
S.; Park, H.-J.; Zee, O. P.; Jung, Y. H. Tetrahedron 2002, 58, 4395.
10. Nadein, O. N.; Kornienko, A. Org. Lett. 2004, 6, 831.
11. (a) Bowen, E. G.; Wardrop, D. J. Org. Lett. 2010, 12, 5330; (b) López, R.; Fernández-Mayorala, A. J.
Org. Chem. 1994, 59, 737.
12. (a) Ballereau, S.; Andrieu-Abadie, N.; Saffon, N.; Génisson, Y. Tetrahedron 2011, 67, 2570; (b)
Shimizu, T.; Osako, K.; Nakata, T. Tetrahedron Lett., 1997, 38, 2685.
16

13. (a) Santella, J. B.; Gardner, D. S.; Yao, W.; Shi, C.; Reddy, P.; Tebben, A. J.; DeLucca, G. V.; Wacker,
ACCEPTED MANUSCRIPT
D. A.; Watson, P. S.; Welch, P. K.; Wadman, E. A.; Davies, P.; Solomon, K. A.; Graden, D. M.;
Yeleswaram, S.; Mandlekar, S.; Kariv, I.; Decicco, C. P.; Ko, S. S.; Carter, P. H.; Duncia, J. V. Bioorg.
Med. Chem. Lett. 2008, 18, 576; (b) Narjes, F.; Koehler, K. F.; Koch, U.; Gerlach, B.; Colarusso, S.;
Steinkühler, C.; Brunetti, M.; Altamura, S.; Francescob, R. D.; Matassa, V. G. Bioorg. Med. Chem.
Lett. 2002, 12, 701; (c) Pilli, R. A.; Andrade, C. K. Z. D.; Souto, C. R. O.; Meijere, A. D. J. Org.
Chem. 1998, 63, 7811; (d) Cane, D. E.; Tan, W.; Ott, W. R. J. Am. Chem. Soc. 1993, 115, 527.
14. (a) Roberts, D. D. J. Org. Chem. 1997, 62, 1857. (d) Krow, G. R.; Yuan, J.; Lin, G.; Sonnet, P. E. Org.
Lett. 2002, 4, 1259.
15. (a) Cheng, J. M. H.; Chee, S. H.; Knight, D. A.; Acha-Orbea, H.; Hermans, I. F.; Timmer, M. S. M.;
Stocker, B. L. Carbohydrate Research 2011, 346, 914; (b) Wang, Z.-M.; Tian, S.-K.; Shi, M. Chirality,
2000, 12, 581.
16. Ragoussis, V.; Perdikaris, S.; Karamolegkos, A.; Magkiosi, K. J. Agric. Food Chem., 2008, 56, 11929.
17