Stereoselective synthesis of (-)-chloramphenicol, (+)-thiamphenicol and (+)-sphinganine via chiral tricyclic iminolactone

Article abstract of DOI:10.1002/cjoc.201201093

The stereoselective syntheses of (-)-chloramphenicol, (+)-thiamphenicol and (+)-sphinganine are described. The two continuous chiral centers within three target molecules were constructed through aldol reaction of chiral tricyclic iminolactone and aldehyde. Concise and efficient syntheses of (-)-chloramphenicol, (+)-thiamphenicol and (+)-sphinganine have been accomplished in practical four or three steps. The synthetic route featured in an aldol reaction between iminolactone 1a and 1b with aldehyde, which introduced the two continuous chiral centers within three target molecules. Copyright

Full text of DOI:10.1002/cjoc.201201093

NOTE
DOI: 10.1002/cjoc.201201093
Stereoselective Synthesis of (−)-Chloramphenicol,
(＋)-Thiamphenicol and (＋)-Sphinganine via
Chiral Tricyclic Iminolactone†
Qiong Li,a,b Hongbo Zhang,a Chenguang Li,a and Pengfei Xu*,a
a State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou
University, Lanzhou, Gansu 730000, China
b College of Pharmacy, Lanzhou University, Lanzhou, Gansu 730000, China
The stereoselective syntheses of (−)-chloramphenicol, (＋)-thiamphenicol and (＋)-sphinganine are described.
The two continuous chiral centers within three target molecules were constructed through aldol reaction of chiral
tricyclic iminolactone and aldehyde.
Keywords β-hydroxy-α-amino alcohol, tricyclic iminolactone, total synthesis
Introduction
cally as a broad spectrum antibiotic and is particularly
useful for the treatment of salmonella, typhi, rickettsia,
and meningeal infections.[7] (＋)-Thiamphenicol (B), an
analogue of A, is bacteriostatic for Gram-positive aer-
obes, Gram-negative aerobes and for some anaerobes.[8]
Recently, interest in glycosphingolipids has in-
creased due to the recognition that they modulate im-
mune responses.[9-11] For example, the β-galactosyl ce-
ramide, plakoside A, isolated from the marine sponge
Plakortis simplex, was found to be a noncytotoxic im-
munosuppressant.[12,13] On the other hand, KRN7000, an
R-galactosyl ceramide identified from SAR studies at
Kirin Brewery, has been shown to be a potent activator
of the immune system.[14,15] However, it is not an easy
task to synthesize glycosphingolipids for extensive re-
search purpose. One of the most challenging aspects of
synthesizing glycosphingolipids is the preparation of the
sphingoid base. (＋)-Sphinganine (C) is an important
part of symbioramide, a new type of bioactive ceramide,
Optically active amino alcohols with vicinal stereo-
centers are important intermediates of drugs and natural
products.[1,2] Bioactive molecules (−)-chloramphenicol
(A), (＋)-thiamphenicol (B) and (＋)-sphinganine (C)
all contain an β-hydroxy-α-amino alcohol fragment
(Figure 1). The pharmacological utility demonstrated by
these compounds themselves or as subunits in larger
structures has stimulated the search for better methods
to achieve their syntheses.[3]
OH
OH
HO
O
HO
O
NH
CHCl2
NH
CHCl2
SO2Me
NO2
(+)-Thiamphenicol (B)
(-)-Chloramphenicol (A)
NH2
OH
12
which is known for increasing sarcoplasmic reticulum
＋
Ca2 -ATPase activity.[16]
OH
(+)-Sphinganine (C)
Owing to the potential bioactive activities of these
three compounds, a number of synthesis methods have
been described.[17-27] As part of our continuous work on
the stereoselective synthesis of α-amino acid using
chiral tricyclic iminolactone which is derived from
natural (1R)-(＋)-camphor,[28-37] we successfully devel-
oped a concise and effective methodology to synthesize
optically pure β-hydroxy-α-amino acid.[16] Structurally,
A, B and C all have a chiral β-hydroxy-α-amino alcohol
fragment which can be prepared by simple reduction of
Figure 1 Representative bioactive molecules containing an
amino alcohol fragment.
(−)-Chloramphenicol (A) is a natural antibiotic with
a relatively broad spectrum of antimicrobial activity.[4,5]
First isolated from Streptomyces venezuelae in 1947,[6]
it was the first antibiotic that was produced in optically
pure and active form by chemical synthesis rather than
by traditional fermentation techniques. It is used clini-
*
E-mail: xupf@lzu.edu.cn; Tel.: 0086-0931-8912281; Fax: 0086-0931-8915557
Received November 7, 2012; accepted November 30, 2012; published online December 27, 2012.
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/cjoc.201201093 or from the author.
Dedicated to the Memory of Professor Weishan Zhou.
†
Chin. J. Chem. 2013, 31, 149—153
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
149

Li et al.
NOTE
β-hydroxy-α-amino acid. Herein, we report a novel and
more efficient method to synthesize these three bioac-
tive compounds using our methodology.
(e.g. benzaldehyde, o-fluorobenzaldehyde, o-chloro-
benzaldehyde and o-methoxybenzaldehyde) in the
presence of 6 equiv. of LiCl, the aldol adducts were ob-
tained in good yield (up to 80%) and high diastereose-
lectivity (up to ＞25∶1 dr). However, low stereoselec-
tivity was observed when 1a reacted with p-nitrobenz-
aldehyde under the same condition due to the high ac-
tivity of p-nitrobenzaldehyde and the strong electron
withdrawing effect of nitro group. Gratifyingly it was
found that 1.3 equiv. of LiClO4 as the additive gave the
significant selectivity (dr＝4∶1). Using more or less
than 1.3 equiv of LiClO4 resulted in no improvement of
diastereoselectivity. With 1.3 equiv. LiClO4 as the addi-
tive, treatment of 1a with LDA at −40 ℃ generated the
corresponding anion which reacted with p-nitrobenz-
aldehyde at −78 ℃ to form compound (S,R)-2a at the
yield of 71%. The reaction proceeds through the transi-
tion state outlined in Scheme 2. If benzene ring is paral-
leled with the iminoloactone ring, it would enforce a π-π
interaction between the benzene ring and the π system
of the iminolactone. Therefore this pathway is favoured
and the compound 2a was obtained with the expected
Results and Discussion
From our previous work (Scheme 1),[36] we know that
when chiral tricyclic iminolactone 1a reacts with an aro-
matic aldehyde, we mainly obtained threo-β-hydroxy-
α-amino acid which has S, R-configuration, which is the
same as that of the (–)-chloramphenicol and (＋)-
thiamphenicol. From the amino acid, only two more
steps are needed to synthesize A and B. On the other
hand, when tricyclic iminolactone 1b reacts with an
aliphatic aldehyde, the erythro-β-hydroxy-α-amino acid
will be the major product. In this case, the chiral amino
acid has R,R-configuration, which is the same as that of
(＋)-sphinganine, and only one more step is needed to
synthesize C from the amino acid. Therefore, from
chiral tricyclic iminolactone, the stereocenters of all the
three target molecules can be constructed by one-step
reaction and a concise and more efficient strategy for
the synthesis of all the three bioactive molecules is de-
veloped.
configuration. The hydrolysis of 2a in 6 mol•L－ HCl
1
solution at 80 ℃ afforded the corresponding threo-β-
hydroxy-α-amino acid 3a in 87% yield. The transforma-
tion of amino acid 3a to amino alcohol 4a was accom-
plished by esterification of 3 with SOCl2 in MeOH
Our synthesis of A (Scheme 2) started with tricyclic
iminolactone 1a. Our previous work demonstrated that
when enolate of 1a reacted with aromatic aldehydes
Scheme 1 Strategy in the synthesis of A, B and C
OH
O
OH
O
aliphatic
aldehyde
aromatic
aldehyde
O
N
O
N
O
OH
R
OH
NH2
threo
NH2
R
O
1b
1a
erythro
OH
(1) reduction
(2) acylation
OH
reduction
OH
R
OH
HN
CHCl2
R
NH2
O
(+)-Sphinganine (C) R = (CH2)14CH3
(-)-Chloramphenicol (A) R = NO2,
(+)-Thiamphenicol (B) R = SO2Me,
Scheme 2 Total synthesis of chloramphenicol and thiamphenicol
H
CHO
O
N
6 mol L-1 HCl
O
N
O
.
O
H
Li
R
O
80 oC
O
N
O
O
ClO4
LiClO4, LDA
- 78 oC
HO
1a
R
R
(71%) 2a R = NO2
(73%) 2b R = SO2Me
TS
O
HO
OH
OH
SOCl2, MeOH
MeO
CHCl2
method a: 90 oC, 3 h.
method b: MeOH, TEA, 30 oC, 8 h
OH
CHCl2
OH
OH
HN
NaBH4
NH2
R
NH2
R
R
O
(87%) 3a R = NO2
(91%) 3b R = SO2Me
(90%) 4a R = NO2
(55%) 4b R = SO2Me
(method a 78%) (-)-Chloramphenicol (A) R = NO2
(method b 95%) (+)-Thiamphenicol (B) R = SO2Me
150
www.cjc.wiley-vch.de
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2013, 31, 149—153

Stereoselective Synthesis of (–)-Chloramphenicol, (＋)-Thiamphenicol and (＋)-Sphinganine
obtained through the hydrolysis of 5 in 6 mol•L－ HCl
at 80 ℃ in 72% yield, the synthesis was completed by
reduction of erythro-β-hydroxy-α-amino acid (6) to the
target molecule (＋)-sphinganine in 53% yield.
1
followed by reduction with NaBH4 in the same pot in
high yield. Finally, amino alcohol 4a was added to
methyl dichloroacetate and heated at 90 ℃ for 3 h to
produce (−)-chloramphenicol in 78% yield (Scheme
2).[17]
Similarly, the synthesis of B (Scheme 2) started with
the aldol reaction of tricyclic iminolactone 1a with
p-methylsulfonylbenzaldehyde in the presence of 1.3
equiv. of LiClO4 as the additive and LDA as the base.
Conclusions
We have developed a novel, concise and efficient
strategy for the total syntheses of bioactive molecules
(–)-chloramphenicol, ( ＋ )-thiamphenicol and ( ＋ )-
sphinganine. The two continuous chiral centers within
three target molecules are introduced in just one single
step via the aldol reaction of the chiral auxiliaries with
aldehydes to produce enantiomerically pure β-hydroxy-
α-amino acids. For the total synthesis of chlorampheni-
col and thiamphenicol, only four steps are needed from
the chiral auxiliary 1a; while for the total synthesis of
sphinganine, only three steps are needed from the chiral
auxiliary 1b.
Subsequent hydrolysis of 2b in 6 mol•L－ HCl solution
1
at 80 ℃ afforded the corresponding threo-β-hydroxy-
α-amino acid 3b in 91% yield. Then the amino acid 3b
was reduced to amino alcohol 4b using the same proto-
col as described above. Finally, amino alcohol 4b was
successfully transformed to B following a literature
procedure.[18] As a summary, through our novel syn-
thetic routes, we not only successfully synthesized
(−)-chloramphenicol and (＋)-thiamphenicol, but also
extended the spectrum of substrates. In our previous
work, we mainly discussed about the electron-rich or
weak electron-deficient benzaldehydes, herein we ex-
tended the range of the substrates to strong electron-
deficient benzaldehydes (p-nitro- and p-(methylsulfonyl)-
benzaldehyde).
The novel synthesis method for (＋)-sphinganine (C)
was also developed using the similar strategy as for the
synthesis of A and B (Scheme 3). From our previous
research, we know that the adducts of 1b with aliphatic
aldehydes have erythro-(R,R)-configuration. Therefore,
our synthesis started with the aldol reaction of tricyclic
iminolactone 1b with hexadecanal using 6 equiv. of
LiCl as the additive. The aldol reaction proceeded for
about 20 h because the solubility of hexadecanal was
low in THF under −78 ℃. Luckily, no obvious decrease
of selectivity was observed. The adduct 5 was obtained
with expected configuration in 70% yield with about
10% of 1b recovered. The reaction proceeds through the
transition state outlined in Scheme 3. The stereoselec-
tivity comes from minimization of nonbonded interac-
tion in the form of a chairlike transition state in which
the alkyl group assumes a pseudoequatorial position.
Then the erythro-β-hydroxy-α-amino acid (6) was
Experimental
(1S,2R,5S,8R,1'R)-5-(1'-Hydroxy-p-nitrobenzyl)-
8,11,11-trimethyl-3-oxa-6-azatricyclo [6.2.1.02,7] un-
dec-6-en-4-one (2a) LiClO4 (208 mg, 1.5 mmol, 1.3
equiv.) was added to a dry 50 mL long-neck flask under
argon. Diisopropylamine (0.234 mL, 1.65 mmol, 1.1
equiv.) in dry THF (8 mL) was added to the long-neck
flask. After the solution was cooled to −40 ℃, n-BuLi
－
1
(2.2 mol•L , 0.750 mL, 1.65 mmol, 1.1 equiv.) was
added dropwise to the cooled solution. The reaction
mixture was stirred at −40 ℃ for 30 min. Tricyclic
iminolactone 1a (310 mg, 1.5 mmol) in dry THF (10 mL)
was added dropwise over a period of 10 min to the
above freshly prepared LDA solution at −40 ℃ while
stirring. The reaction mixture was subsequently cooled
to −78 ℃ and the stirring was continued for 1 h fol-
lowed by the dropwise addition of the solution of
p-nitrobenzaldehyde (272 mg, 1.8 mmol, 1.2 equiv.) in
dry THF (20 mL) over a period of 15 min with vigorous
stirring. And then the well-stirred reaction was
quenched by adding saturated NH4Cl (1 mL) solution at
−78 ℃. The reaction was warmed up to r.t., and the
solvent was removed under reduced pressure and the
residue was diluted with water and then extracted with
ethyl acetate (15 mL×3), the combined organic phase
was washed with water and brine, dried over MgSO4
and concentrated to give the crude product. The crude
product was purified by column chromatography (petrol
ether/EtOAc 3∶1) to yield desired compound 2a (381
mg, 71 %). White solid, [α]2D7 −86 (c 0.028, CHCl3);
Scheme 3 Total synthesis of (＋)-sphinganine
O
R1
H
N
13 H
N
O
O
O
Li
LiCl, LDA
- 78 oC
70%
O
H
O
1b
TS
R
1 = (CH2)14CH3
OH
O
6 mol L-1 HCl
.
N
O
m.p. 75－78 ℃; IR (film) ν: 3384, 2925, 1740, 1521,
OH
－
1
1
80 oC
13
13
1346 cm ; H NMR (400 MHz, CDCl3) δ: 8.2 (d, J＝
8.8 Hz, 2H), 7.52 (d, J＝8.4 Hz, 2H), 5.51 (t, J＝4.0 Hz,
1H), 4.75 (d, J＝3.6 Hz, 1H), 4.54 (s, 1H), 3.25 (d, J＝
4.4 Hz, 1H), 2.15 (d, J＝4.4 Hz, 1H), 2.03－1.75 (m,
1H), 1.66－1.59 (m, 1H), 1.33－1.23 (m, 1H), 0.97 (s,
3H), 0.94 (s, 3H), 0.75 (s, 3H); 13C NMR (100 MHz,
NH2
OH
O
72 %
5
6
OH
SOCl2, MeOH
OH
NaBH4
53 %
NH2
(+)-Sphinganine (C)
Chin. J. Chem. 2013, 31, 149—153
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
151

Li et al.
NOTE
CDCl3) δ: 184.2, 170.9, 147.1, 127.4, 123.5, 80.3, 74.9,
67.0, 53.3, 48.3, 47.7, 29.4, 26.1, 20.1, 19.5, 10.1.
HRMS (ESI) calcd for C19H22N2O5[M＋H]＋: 359.1601,
found 359.1606.
Hz, 1H), 3.39－3.33 (m, 1H); 13C NMR (100 MHz,
DMSO-d6) δ: 163.4, 151.2, 146.4, 127.3, 122.9, 69.0,
66.4, 60.2, 56.8.
(2S,3R)-2-Amino-3-hydroxy-3-(p-nitrophenyl)-
propanoic acid (3a) The aldol product (380 mg, 1.06
Acknowledgement
mmol) was dissolved in 6 mol•L－ HCl (19 mL) in a
1
We are grateful for the National Basic Research
Program of China (No. 2011CB833200), the National
Natural Science Foundation of China (Nos. 20772051,
20972058), the “111” Program from MOE of P. R.
China and the Fundamental Research Funds for the
Central Universities (lzujbky-2012-90).
sealed tube with a Teflon screw cap and heated at 80 ℃
for 3.5 h. After cooling to r.t., water (5 mL) was added
and the mixture was extracted with diethyl ether (5 mL
×3). The aqueous layer was evaporated under reduced
pressure and the residue was dissolved in anhydrous
ethanol. Propylene oxide (3 mL) was then added and the
mixture was stirred at r.t. for 30 min during which time
light yellow solids precipitated. The precipitate was
collected by centrifugation, washed successively with
cold EtOAc (2 mL×2) and Et2O (4 mL×1), and air
dried to give the desired free threo-β-hydroxy-α-amino
acid 3a (211 mg, 87%). Light yellow solid, [α]2D6 −12
(c 0.044, H2O); m.p. 184－186 ℃; 1H NMR (400 MHz,
D2O) δ: 8.32 (d, J＝8.8 Hz, 2H), 7.71 (d, J＝8.4 Hz,
2H), 5.43 (d, J＝4.4 Hz, 1H), 3.98 (d, J＝4.4 Hz, 1H);
13C NMR (100 MHz, D2O) δ: 171.5, 147.6, 147.0, 127.1,
124.0, 70.7, 60.5. HRMS (ESI) calcd for C9H10N2O5 [M
＋H]＋: 227.0662, found 227.0654.
References
[1] Nakanishi, K.; Goto, T.; Ito, S.; Natoro, S. In Natural Product
Chemistry, Vol. 3, Oxford Press, Oxford, 1983.
[2] Garner, P.; Ramakanth, S. J. Org. Chem. 1986, 51, 2609.
[3] Corey, E. J.; Choi, S. Tetrahdron Lett. 2000, 41, 2765, and refer-
ences cited therein.
[4] Goodman and Gillman’s The Pharmacological Basis of Therapeu-
tics, 6th ed., Macmillan Publishing Co., New York, 1980, pp. 1191
－1199.
[5] The Merck Index, 10th ed., Merck, Rahway, NJ, 1983, p. 2036, entry
2035.
[6] Ehrlich, J.; Bartz, Q. R.; Smith, R. M.; Josylyn, D. A.; Burkholder, P.
R. Science 1947, 106, 417.
[7] Physicians’s Desk Reference, 46th ed., Medical Economics Data,
Montvale, NJ, 1992.
[8] Cutler, R. A.; Stenger, R. J.; Suter, C. M. J. Am. Chem. Soc. 1952,
74, 5475.
[9] Merrill, A. H., Jr.; Sweeley, C. C. In Biochemistry of Lipids, Lipo-
proteins and Membranes, Vol. 31, Eds.: Vance, D. E.; Vance, J., El-
sevier, Amsterdam, 1996, pp. 309－339.
[10] Hannun, Y. A. Sphingolipid-Mediated Signal Transduction, R. G.
Landes Co., Austin, 1997.
[11] Porcelli, S. A.; Modlin, R. L. Annu. Rev. Immunol. 1999, 17, 297.
[12] Nicolaou, K. C.; Li, J.; Zenke, G. Helv. Chim. Acta 2000, 83, 1977.
[13] Costantino, V.; Fattorusso, E.; Mangoni, A.; Di Rosa, M.; Ianaro, A.
J. Am. Chem. Soc. 1997, 119, 12465.
[14] Kawano, T.; Cui, J.; Koezuka, Y.; Toura, I.; Kaneko, Y.; Motoki, K.;
Ueno, H.; Nakagawa, R.; Sato, H.; Kondo, E.; Koseki, H.; Taniguchi,
M. Science 1997, 278, 1626.
[15] Morita, M.; Motoki, K.; Akimoto, K.; Natori, T.; Sakai, T.; Sawa, E.;
Yamaji, K.; Koezuka, Y.; Kobayashi, E.; Fukushima, H. J. Med.
Chem. 1995, 38, 2176.
[16] Azuma, H.; Takao, R.; Niiro, H.; Shikata, K.; Tamagaki, S.; Tachi-
bana, T.; Ogino, K. J. Org. Chem. 2003, 68, 2790.
[17] George, S.; Narina, S. V.; Sudalai, A. Tetrahedron 2006, 62, 10202,
and references cited therein.
(2R,3R)-2-Amino-3-hydroxy-3-(p-nitro-phenyl)-1-
propanol (4a) The 3a (45 mg, 0.2 mmol) was added
to absolute methanol (2 mL) while stirring, then freshly
distilled thionyl chloride (0.088 mL, 1.2 mmol, 6 equiv.)
was added to the stirred suspension of 3a and the mix-
ture was heated at 40 ℃ while stirring for 2－3 d (TLC
monitored). Following the completion of reaction, the
excess thionyl chloride was evaporated under reduced
pressure. Then absolute methanol (2 mL) and NaBH4
(75 mg, 2 mmol, 10 equiv.) were added to the residue.
The reaction was performed at 60 ℃ until the TLC
analysis showed the reaction was complete. The crude
product was purified by column chromatography (me-
thylene chloride/methanol/aqueous ammonia 90∶9∶1
to 60∶30∶10) to yield desired compound 4a (38 mg,
90%) as light yellow solid. 1H NMR (400 MHz, D2O) δ:
8.33 (d, J＝8.8 Hz, 2H), 7.71 (d, J＝8.4 Hz, 2H), 5.05
(d, J＝3.2 Hz, 1H), 3.74 (dd, J＝11.4, 3.4 Hz, 1H), 3.65
－3.56 (m, 2H); 13C NMR (100 MHz, D2O) δ: 150.5,
149.2, 130.4, 126.8, 72.5, 61.1, 60.4.
[18] Lu, W.; Chen, P.; Lin, G. Tetrahedron 2008, 64, 7822, and refer-
ences cited therein.
(1R,2R)-2-(Dichloroaceramido)-1-(p-nitrophenyl)-
1,3-propanediol (Chloramphenicol A) A large ex-
cess of methyl dichloroacetate was added to 4a and
heated at 90 ℃ while stirring for about 3 h (TLC
monitored). The excess methyl dichloroacetate was re-
moved under reduced pressure and the crude product
was purified by column chromatography (petrol
ether/EtOAc 3 ∶ 7) to give Chloramphenicol A.[17]
[19] Reist, E. J.; Christie, P. H. J. Org. Chem. 1970, 55, 3521.
[20] Roush, W. R.; Adam, M. A. J. Org. Chem. 1985, 50, 3752.
[21] Masui, M.; Shioiri, T. Tetrahedron Lett. 1998, 39, 5199.
[22] Azuma, H.; Tamagaki, S.; Ogino, K. J. Org. Chem. 2000, 65, 3538.
[23] Cook, G. R.; Pararajasingham, K. Tetrahdron Lett. 2002, 43, 9027.
[24] Ndakala, A. J.; Hashemzadeh, M.; So, R. C.; Howell, A. R. Org. Lett.
2002, 4, 1719.
[25] Yun, J. M.; Sim, T. B.; Hahm, H. S.; Lee, W. K. J. Org. Chem. 2003,
68, 7674.
[26] So, R. C.; Ndonye, R.; Izmirian, D. P.; Richardson, S. K.; Guerrera,
R. L.; Howell, A. R. J. Org. Chem. 2004, 69, 3233.
[27] Zhong, Y. W.; Dong, Y. Z.; Fang, K.; Izumi, K.; Xu, M. H.; Lin, G.
Q. J. Am. Chem. Soc. 2005, 127, 11956.
1
2
6
[α]D −25 (c 0.031, EtOAc); m.p. 150－151 ℃; H
NMR (400 MHz, DMSO-d6) δ: 8.31 (d, J＝8.8 Hz, 1H),
8.17 (d, J＝8.4 Hz, 2H), 7.60 (d, J＝8.8 Hz, 2H), 6.48 (s,
1H), 6.04 (d, J＝4.4 Hz, 1H), 5.06 (dd, J＝4.0, 2.4 Hz,
1H), 4.98 (dd, J＝6.0, 5.2 Hz, 1H), 3.59 (dd, J＝6.0, 2.6
152
www.cjc.wiley-vch.de
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2013, 31, 149—153

Stereoselective Synthesis of (–)-Chloramphenicol, (＋)-Thiamphenicol and (＋)-Sphinganine
[28] Xu, P.-F.; Chen, Y. S.; Lin, S. I.; Lu, T. J. J. Org. Chem. 2002, 67,
2309.
[29] Xu, P.-F.; Lu, T. J. J. Org. Chem. 2003, 68, 658.
[30] Li, S.; Hui, X. P.; Yang, S. B.; Jia, Z. J.; Xu, P.-F.; Lu, T. J.
Tetrahedron: Asymmetry 2005, 16, 1729.
Chem. 2008, 73, 3634.
[34] Wang, H. F.; Ma, G. H.; Yang, S. B.; Han, R. G.; Xu, P.-F.
Tetrahedron: Asymmetry 2008, 19, 1630.
[35] Huang, Y.; Li, Q.; Liu, T. L.; Xu, P.-F. J. Org. Chem. 2009, 74,
1252.
[31] Xu, P.-F.; Li, S.; Lu, T. J.; Wu, C. C.; Fan, B.; Golfis, G. J. Org.
Chem. 2006, 71, 4364.
[36] Li, Q.; Yang, S. B.; Zhang, Z.; Li, L.; Xu, P.-F. J. Org. Chem. 2009,
74, 1627.
[32] Wang, P.-F.; Gao, P.; Xu, P.-F. Synlett 2006, 7, 1095.
[33] Zhang, H.-H.; Hu, X. Q.; Wang, X.; Luo, Y.-C.; Xu, P.-F. J. Org.
[37] Luo, Y.-C.; Zhang, H.-H.; Wang, Y.; Xu, P.-F. Acc. Chem. Res.
2010, 43, 1317.
(Cheng, F.)
Chin. J. Chem. 2013, 31, 149—153
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
153