Synthesis of cyclic phosphonate analogues of (lyso)phosphatidic acid using a ring-closing metathesis reaction

Article abstract of DOI:10.1021/jo0607919

We describe a versatile and efficient method for the preparation of acyloxy-substituted six-membered cyclic phosphonates using the ring-closing metathesis. After closure, the key cyclic phosphonate intermediate was dihydroxylated and converted to a new cl

Full text of DOI:10.1021/jo0607919

Synthesis of Cyclic Phosphonate Analogues of (Lyso)phosphatidic
Acid Using a Ring-Closing Metathesis Reaction
Honglu Zhang,† Ryoko Tsukuhara,‡ Gabor Tigyi,‡ and Glenn D. Prestwich*,†
The Department of Medicinal Chemistry, The UniVersity of Utah, 419 Wakara Way, Suite 205,
Salt Lake City, Utah 84108-1257, and Department of Physiology, UniVersity of Tennessee Cancer Institute,
UniVersity of Tennessee Health Science Center, Memphis, Tennessee 38163
gprestwich@pharm.utah.edu
ReceiVed April 13, 2006
We describe a versatile and efficient method for the preparation of acyloxy-substituted six-membered
cyclic phosphonates using the ring-closing metathesis. After closure, the key cyclic phosphonate
intermediate was dihydroxylated and converted to a new class of conformationally constrained PA and
LPA analogues. The oleoyloxy-substituted cyclic phosphonate 4 had unique receptor-selective properties
as a ligand, showing partial activation of the LPA2 GPCR and weak antagonism of the LPA1 GPCR.
Introduction
neointimal thickening during atherosclerosis.7,8 The importance
of LPA receptors and downstream signaling events as a rich
source of potential therapeutic targets has led to increased
interest in the functional lipidomics of LPA and LPA binding
proteins.9,10 In addition, LPA signaling and biosynthesis via
lysoPLD11 are under active investigation for new cancer
therapies.12-14 In addition, LPA signaling regulates aspects of
neural development.15
The pleiotropic actions of LPA can be dissected by appreciat-
ing receptor isoform-specific physiology,16 and to this end LPA
analogues with isoform-selective agonist and antagonist activi-
ties are urgently needed. LPA1 is essential for cell invasion in
cancer17 and this isoform plays a crucial role in brain develop-
ment.18,19 The absence of LPA1 expression results in craniofacial
Lysophosphatidic acid (LPA) and phosphatidic acid (PA)
elicit a rich palette of biological responses in human health and
pathophysiology.1-3 The majority of these cellular events are
transduced via three G-protein-coupled receptors (GPCRs):
LPA1, LPA2, and LPA3.4 Recently, two additional LPA effec-
tors, LPA4/GPR235 and the nuclear transcription factor PPARγ,
have been reported.6 While the importance of LPA4 remains
unknown, PPARγ appears to mediate the action of LPA in
* To whom correspondence should be addressed. Phone: +1-801-585-9051.
Fax: +1-801-585-9053.
† The University of Utah.
‡ University of Tennessee Health Science Center.
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10.1021/jo0607919 CCC: $33.50 © 2006 American Chemical Society
Published on Web 07/01/2006
J. Org. Chem. 2006, 71, 6061-6066
6061

Zhang et al.
dimorphism, semilethality due to defective suckling behavior,
and generation of a small fraction of pups with frontal
hematoma.18 Although LPA2 is not essential for normal mouse
development, it acts redundantly with LPA1 to mediate LPA
responses in fibroblasts.20 LPA3 has recently been found to be
critically important for embryo implantation and spacing.21 In
addition, phosphatidic acid (PA) regulates phosphoinositide
metabolism and plays key roles in cell growth and protein
trafficking.22 PA is thus an important lipid mediator of cellular
physiology, and its metabolism,23 and interactions with PA-
binding proteins deserve continued attention.24 In addition, short
chain PA analogues have proven to be important bioactive
ligands of the LPA GPCRs.25
FIGURE 1. (Top) LPA and pyran analogue; (bottom) target racemic
cyclic phosphonates 1-5.
The search for metabolically stabilized, receptor-isoform
specific agonists and antagonists for LPA receptors has been
an ongoing focus of our research26-33 and that of others.25,34-36
By targeting one of five receptors, we can separate the
overlapping effects of the native ligand. Moreover, the produc-
tion of metabolically stabilized analogues that can resist acyl
migration and hydrolysis, as well as phosphatase and acyltrans-
ferase activities, provides more useful ligands for cellular and
organismal biology.
Recently, the Shibasaki research group reported a selective
LPA1 agonist that can distinguish between LPA1 and LPA2.37
Inspired by the selectivity of these cyclic deoxysugar-like
agonists for LPA1 and LPA2, and intrigued by the antimetastatic
properties of five-membered ring cyclic phosphatidic acid38 and
its modeling into the LPA GPCRs,25 we designed a new family
of six-membered ring cyclic phosphonates (Figure 1). These
molecules provide conformational constraint by converting the
glyceryl backbone to a ring structure and metabolic stabilization
via the phosphonate.37 Herein we describe the synthesis of
analogues 1-5 using a ring-closing metathesis reaction as the
key step to form the cyclic phosphonate; we further demonstrate
the biological activities of these new LPA and PA analogues
with the three canonical LPA1, LPA2, and LPA3 GPCRs.
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Results and Discussion
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The ring-closing metathesis (RCM) is an efficient approach
for the preparation of P-sugars.39,40 Indeed, the diastereoselective
RCM in the synthesis of P-stereogenic phosphinates also
revealed the power of RCM reaction in generating P-heterocy-
cles that have potential utility in drug development.41 We
envisaged the use of RCM to construct the phosphonate building
block 9. To accommodate both saturated and unsaturated acyl
groups, we used two different protecting groups. The phenyl
phosphonate substrate was acceptable for palmitoyl analogues,
because reductive deprotection could be used.39 For the oleoy-
loxy-substituted cyclic phosphate, we used a methyl phosphonate
that could be deprotected with TMSBr/CH2Cl2 without reduction
of the oleoyl olefinic bond.
The diphenyl allylphosphonate 7 was prepared (Scheme 1)
using the reaction of diphenyl phosphoryl chloride with allyl-
magnesium bromide in refluxing ether.42 One of the two
phenoxy groups of the resulting diphenyl allyl phosphate 7 was
subsequently displaced with lithium allyloxide in THF/HMPA
(4:1)43 to give the diene 8 as the main product in 58% yield.39,43
The amount of diallyl side product was minimized by using
(17) Hama, K.; Aoki, J.; Fukaya, M.; Kishi, Y.; Sakai, T.; Suzuki, R. J.
Biol. Chem. 2004, 279, 17634-17639.
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6062 J. Org. Chem., Vol. 71, No. 16, 2006

Phosphonate Analogues of (Lyso)phosphatidic Acid
SCHEME 1. Construction of Key Intermediate 9 Using
RCMa
of the intermediate osmate ester to afford diol 10 in high yield
but with essentially no diastereoselectivity (ds ) 1:1).39,40
Acylation of diol 10 with palmitic acid in CH2Cl2 using the
water-soluble carbodiimide EDCI as condensation reagent
afforded two desired products, the bisacylated PA analogue and
monoacylated LPA analogue. 1H NMR spectroscopy, including
1H-1H COSY, allowed identification of the products as the
dipalmitoyloxy-substituted cyclic phosphonate 11 and 4-palmi-
toyloxy-cyclic phosphonate 12. For example, palmitoylation of
the 4-OH caused the H4 resonance to shift downfield to ca. 5.2
ppm; from the 1H-1H COSY spectrum, a strong correlation was
observed between H3 (R-H of phosphonate) and H4 but not
between H3 and H5. The free cyclic phosphonic acids were
obtained in excellent yields by reductive cleavage of the phenyl
phosphonates with 1 atm H2/PtO2 in MeOH.
a Reagents and conditions: (a) allylmagnesium bromide, Et2O, reflux,
10 h, 21%; (b) allyl alcohol, n-BuLi, THF/HMPA (4:1), -78 °C, 2 h, 58%;
(c) Grubbs catalyst, CH2Cl2, reflux, 8 h, 90%.
Scheme 3 shows the modified route employed to obtain the
unsaturated oleoyloxy analogues. Reaction of 9 with lithium
methoxide in methanol at -5 °C replaced the phenoxy group
with a methoxy protecting group to give desired cyclic phos-
phonate 13 in high yield. Dihydroxylation as shown in Scheme
2 afforded diol 14. Acylation of diol 14 with oleic acid was
conducted in CH2Cl2/DMF instead of CH2Cl2, because of the
poor solubility of diol 14 in CH2Cl2. Three separable products
short reaction times and by minimizing the excess of the
allyloxide. Treatment of phosphonate 8 with first generation
Grubbs metathesis catalyst44 afforded the unsaturated six-
membered cyclic phosphonate 9 in high yield.
Next, catalytic dihydroxylation of cyclic olefin in 9 (OsO4/
NMO/acetone/H2O) provided diol 10 in modest yield, but TLC
indicated complete consumption of starting material. Simply
adding citric acid to the reaction mixture resulted in hydrolysis
SCHEME 2. Synthesis of Racemic Palmitoyloxy Analogues 1 and 2a
a Reagents and conditions: (a) OsO4, NMO, citric acid, acetone/t-BuOH, 75%; (b) palmitic acid, EDCI, DMAP, CH2Cl2, 28% of 11, 48% of 12; (c) PtO2,
MeOH, H2, 74% of 1, 82% of 2.
SCHEME 3. Synthesis of Oleoyloxy Analogues 3, 4, and 5a
a Reagents and conditions: (a) MeOH, n-BuLi, 89%; (b) QsO4, NMO, citric acid, acetone/t-BuOH, 78%; (c) oleic acid, EDCI, DMAP, CH2Cl2/DMF
(3:1), 18% of 15, 38% of 16, 12% of 17; (d) TMSBr, CH2Cl2.
J. Org. Chem, Vol. 71, No. 16, 2006 6063

Zhang et al.
TABLE 1. Activity of 2, 4, and 5 on LPA Receptors
LPA1
LPA2
LPA3
EC50
IC50
(inhib %)c
nM
EC50
IC50
(inhib %)
nM
EC50
(Emax)
nM
IC50
(inhib %)c
nM
a
(Emax
)
(Emax
)
cmpd
nM
nM
PPARγ
2
4
5
NEb
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
>307 (33.6 at 30 µM)
97 (41.6)
>6380 (39.2 at 30 µM)
>11300 (56.8 at 30 µM)
>1200 (45.5 at 30 µM)
NE
>7510 (10.8 at 30 µM)
a Emax ) maximal efficacy of compound/maximal efficacy of LPA 18:1 × 100. b NE ) no effect was shown at the highest concentration (30 µM) tested.
c Inhib % ) % maximal inhibition of the response to 200 nM of LPA 18:1.
were obtained and were identified with H NMR and H-1H
COSY as dioleoyloxy-substituted cyclic phosphonate 15 and
both the 4- and 5-oleoyloxy cyclic phosphonates 16 and 17.
Reaction of these intermediates with TMSBr in dry CH2Cl2
provided the three cyclic phosphonic acids 3-5 in high yield.
We examined the potency of monoacyloxy cyclic phosphates
2, 4, and 5 for activation of three LPA GPCRs (LPA1, LPA2,
and LPA3) and with the nuclear receptor PPARγ. None of the
analogues activated PPARγ. Among the three GPCRs, LPA2
was found to be selectively activated by the cyclic phosphate
4. This is a noteworthy result, as it has been difficult to prepare
selective agonists capable of distinguishing LPA1 and LPA2.
This experiment also suggested that the new LPA scaffold can
be recognized by the GPCRs and indicates that additional
modeling25,35 could be instructive. LPA analogues with oleoyl
chains are generally more potent ligands for LPA3 than those
with palmitoyl chains.30,31 This attribute was born out also in
these studies (Table 1), since oleoyloxy-substituted cyclic
phosphonates 4 and 5 can be recognized by the three LPA
receptors, while the palmitoyl-substituted cyclic phosphonate
2 has little or no interaction with these receptors. Moreover,
the position of the oleoyloxy group in the cyclic phosphonates
is also important. Analogue 4 is a selective agonist of LPA2
and an antagonist of LPA1 and LPA3, while phosphonate 5 is
an antagonist of LPA1 and an agonist of LPA2 and LPA3. On
the basis of these structure-activity relationships, stereoselective
synthesis or introducing another functional group to change the
three-dimensional arrangement of cyclic phosphonate 4 and 5
to selectively meet certain receptors may enhance the selective
activation with LPA receptors.
1
1
The reaction mixture was heated for 1 h, and then a solution of
ClPO(OPh)2 (10 mmol) in ether (50 mL) was added. The reaction
was refluxed overnight. Then it was cooled, and water (50 mL)
was added. The organic layer was dried on Na2SO4, ether was
removed by evaporating, and residue was distilled with yield of
21%. 1HNMR(400 MHz, CDCl3) δ 7.33-7.29 (m, 4H), 7.20-7.13
(m, 6H), 5.99-5.87 (m, 1H), 5.36-5.29 (m, 2H), 2.98 (dt, J )
7.6, 1.2 Hz, 1H), 2.92 (dt, J ) 7.6, 1.2 Hz, 1H).
Allylphosphonic Acid Phenyl Ester Allyl Ester (8). To a
solution of the allyl alcohol (0.42 mL, 6.06 mmol) in 15 mL of
dry THF was added n-BuLi (2.40 mL, 2.5 M in hexanes) at -45
°C, and the solution was warmed to room temperature over 2 h.
This solution was added to the diphenyl allylphosphonate (1.00 g,
3.64 mmol) in 16 mL of THF and 4 mL of HMPA at -78 °C over
2 h. After an additional hour at -78 °C, the reaction mixture was
quenched with saturated NH4Cl, extracted with EtOAc, and dried
with Na2SO4. Removal of the solvent and flash chromatography
1
(hexanes/EtOAc 3:1) afforded 8 (503 mg, 58.0%) as an oil. H
NMR (400 MHz, CDCl3): δ 7.32-7.10 (m, 5H), 5.92-5.77 (m,
2H), 5.33-5.18 (m, 4H), 4.66-4.51(m, 2H), 2.79 (d, J ) 7.6 Hz,
1H), 2.74 (d, J ) 7.6 Hz, 1H). 31P NMR (162 MHz, CDCl3): δ
25.33. 13C NMR (101 MHz, CDCl3): δ 150.7, 150.6, 132.8, 132.8,
129.9, 126.9, 126.8, 125.2, 121.0, 120.9, 120.8, 120.7, 118.4, 67.2,
67.2, 32.6, 31.3. MS (CI): 239.1 [M + H]+. CI-HRMS: [M +
H]+ calcd for C12H16O3P, 239.0837; found, 239.0822.
2-Phenoxy-3,6-dihydro-1,2-oxaphosphinine-2-oxide (9). To a
solution of 8 (300 mg, 1.26 mmol) in 80 mL of dry CH2Cl2 was
added catalyst (PCy3)2Cl2RudCHPh (45 mg, 3% mol), and the
mixture was refluxed for 8 h, diluted with CH2Cl2, flushed with
air, and stirred overnight at room temperature. Removal of the
solvent and flash chromatography (hexanes/EtOAc 2:1) afforded
9 (240 mg, 90%) as an oil. 1H NMR (400 MHz, CDCl3): δ 7.26-
7.05 (m, 5H), 5.74-5.60 (m, 2H), 4.84-4.72 (m, 2H), 2.61-2.42
(m, 2H). 31P NMR (162 MHz, CDCl3): δ 16.90. 13C NMR (101
MHz, CDCl3): δ 150.3, 150.3, 130.0, 125.5, 125.4, 125.2, 120.3,
120.3, 120.2, 70.1, 70.0, 22.7, 21.4. MS (CI): 211.0 [M + H]+.
CI-HRMS: [M + H]+ calcd for C10H12O3P, 211.0524; found,
211.0517.
Conclusion
We describe a facile RCM/dihydroxylation strategy to gener-
ate several novel cyclic phosphonate analogues of PA and LPA.
This method permits the preparation selective agonists and
antagonists with a novel phosphatase-resistant and conforma-
tionally constrained scaffold. The interaction experiment of LPA
analogues 2, 4, and 5 with LPA receptors showed that the
oleoyloxy-substituted cyclic phosphonate 4 is a potential selec-
tive LPA2 agonist that can distinguish LPA1 and LPA2.
2-Phenoxy-1,2-oxaphosphorinane-4,5-diol-2-oxide (10). To a
solution of 9 (200 mg, 0.95 mmol) in 10 mL of acetone and 4 mL
of t-BuOH were added citric acid (225 mg, 1.17 mmol), NMO
hydrate (140 mg, 1.03 mmol), and OsO4 (2 drops 2.5 wt % solution
in 2-propanol). After 48 h, removal of the solvent and flash
chromatography (EtOAc/MeOH 9:1) afforded 10 (175 mg, 75%)
1
as an oil. H NMR (400 MHz, CDCl3): δ 7.26-7.04 (m, 5H),
4.32-3.99 (m, 5H), 3.80-3.77 (m, 1H), 2.33-2.21 (m, 1.2H),
2.11-2.01 (m, 0.8H). 31P NMR (162 MHz, CDCl3): δ 23.57, 23.55.
13C NMR (101 MHz, CDCl3): δ 150.0, 149.9, 149.8, 149.7, 130.3,
130.1, 125.7, 125.7, 120.8, 120.8, 120.2, 120.2, 69.9, 69.8, 68.5,
68.2, 67.9, 67.9, 67.8, 67.7, 67.5, 67.5, 27.9, 27.7, 26.7, 26.5. MS
(CI): 245.0 [M + H]+. CI-HRMS: [M + H]+ calcd for C10H14O5P,
245.0579; found, 245.0577.
Experimental Section
Diphenyl Allylphosphonate (7). Mg (2.4 g, 10 mmol) was
placed in a dry, three-necked flask equipped with condenser and
additional funnel. Dry ether (75 mL) followed by a solution of
allylbromide (8.64 mL, 10 mmol) in ether (50 mL) was added.
2-Phenoxy-1,2-oxaphosphorinane-4,5-O-dipalmitoyl-2-oxide
(11) and 2-Phenoxy-1,2-oxaphosphorinane-4-O-palmitoyl-5-hy-
droxy-2-oxide (12). A solution of diol 10 (50 mg, 0.21 mmol),
palmitic acid (52 mg, 0.22 mmol), EDCI (88 mg, 0.46 mmol), and
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6064 J. Org. Chem., Vol. 71, No. 16, 2006

Phosphonate Analogues of (Lyso)phosphatidic Acid
DMAP (28 mg, 0.23 mmol) in 4 mL of dry CH2Cl2 was stirred
overnight at room temperature. The reaction mixture was diluted
with CH2Cl2, washed with water, and dried with Na2SO4. Concen-
tration of the solvent gave a crude residue, which was purified by
column chromatography (EtOAc/hexanes 1:2 to 5:1) to afford 11
(42 mg, 28%) and 12 (47 mg, 48%) as white solids.
[M + H]+. CI-HRMS: [M + H]+ calcd for C5H10O3P, 149.0358;
found, 149.0353.
2-Methoxy-1,2-oxaphosphorinane-4,5-diol-2-oxide (14). To a
solution of 13 (26 mg, 0.18 mmol) in 2 mL of acetone and 0.8 mL
of t-BuOH were added citric acid (45 mg, 0.24 mmol), NMO
hydrate (27 mg, 0.20 mmol), and OsO4 (3 drops of a 2.5% solution
in 2-propanol). After 48 h, the solvent was removed under reduced
pressure. The residue was flash chromatographed (EtOAc/MeOH
4:1) to afford 14 (25 mg, 78%) as an oil.1H NMR (400 MHz,
CDCl3): δ 4.443 (br, -OH, 2H), 4.31-4.13 (m, 2H), 4.02 (m,
1H), 3.91 (s, 1H), 3.73 (dd, J ) 24.8, 11.2 Hz, 3H), 2.30-2.06
(m, 2H). 31P NMR (162 MHz, CDCl3): δ 28.39, 28.14. 13C NMR
(101 MHz, CDCl3): δ 69.3, 69.2, 68.6, 68.3, 68.2, 68.17, 67.7,
53.2, 53.1, 51.97, 51.9, 27.3, 26.1, 26.1. MS (CI): 183.0 [M +
H]+. CI-HRMS: [M + H]+ calcd for C5H12O5P, 183.0422; found,
183.0432.
Compound 11. 1H NMR (400 MHz, CDCl3): δ 7.31-7.11 (m,
5H), 5.45 (m, 1H), 5.22 (d, br, J ) 2.8 Hz, 1H), 4.41-4.28 (m,
2H), 2.45-2.28 (m, 2H), 2.25 (q, J ) 8.8 Hz, 4H), 1.53 (t, J ) 6.8
Hz, 4H), 1.18 (s, 48H), 0.81 (t, J ) 6.8 Hz, 6H). 31P NMR (162
MHz, CDCl3): δ 19.70. 13C NMR (101 MHz, CDCl3): δ 172.6,
172.5, 150.1, 150.0, 130.1, 125.7, 120.5, 120.5, 67.2, 67.1, 67.1,
65.9, 65.8, 34.3, 34.2, 32.1, 29.9, 29.88, 29.85, 29.7, 29.69, 29.6,
29.5, 29.3, 29.3, 26.4, 25.2, 25.1, 24.9, 22.9, 14.3. MS (MALDI):
743.5 [M + Na]+. MALDI-HRMS: [M + Na]+ calcd for C42H73-
NaO7P, 743.5275; found, 743.5278.
Compound 12. 1H NMR (400 MHz, CDCl3): δ 7.36-7.17 (m,
5H), 5.42 (m, 1H), 4.45-4.37 (m, 1H), 4.31 (dt, J ) 12.4, 2.8 Hz,
1H), 4.11 (m, 1H), 2.53 (m, 1H), 2.35 (m, 3H), 1.62 (t, J ) 7.2
Hz, 2H), 1.24 (s, 24H), 0.87 (t, J ) 6.8 Hz, 3H). 31P NMR (162
MHz, CDCl3): δ 19.91. 13C NMR (101 MHz, CDCl3): δ 173.2,
150.1, 149.99, 130.1, 125.6, 120.4, 120.4, 69.6, 69.6, 67.7, 67.6,
66.7, 66.6, 34.5, 32.1, 29.9, 29.9, 29.8, 29.8, 29.6, 29.59, 29.46,
29.3, 26.0, 25.0, 24.8, 22.9, 14.3. MS (MALDI): 483.33 [M +
H]+. MALDI-HRMS: [M + H]+ calcd for C26H44O6P, 483.3116;
found, 483.3112.
2-Methoxy-1,2-oxaphosphorinane-4,5-O-dioleoyl-2-oxide (15).
A solution of diol 14 (80 mg, 0.44 mmol) and oleic acid (108 mg,
0.38 mmol), EDCI (176 mg, 0.92 mmol), and DMAP (56 mg, 0.44
mmol) in 9 mL of dry CH2Cl2 and 3 mL of DMF was stirred
overnight at room temperature. The reaction mixture was diluted
with CH2Cl2, washed with water, and dried with Na2SO4. Concen-
tration of the solvent gave a crude residue, which was purified by
column chromatography (EtOAc /hexanes 1:1 to EtOAc/MeOH 20:
1) to afford 15 (55 mg, 18%), 16 (75 mg, 38%), and 17 (23 mg,
1
12%). H NMR (400 MHz, CDCl3): δ 5.41-5.34 (m, 1H), 5.27
(q, J ) 5.6 Hz, 4H), 5.20 (m, 1H), 4.31-4.05 (m, 2H), 3.77 (dd,
J ) 16.8, 10.8 Hz, 3H), 2.30 (m, 2H), 2.21 (m, 4H), 1.94 (d, J )
5.2 Hz, 8H), 1.55 (m, 4H), 1.23 (m, 40H), 0.81 (t, J ) 6.8 Hz,
6H). 31P NMR (162 MHz, CDCl3): δ 25.35, 24.05. 13C NMR (101
MHz, CDCl3): δ 172.7, 172.4, 130.3, 130.27, 129.9, 129.8, 67.5,
67.3, 67.27, 65.6, 53.1, 51.2, 34.4, 34.3, 34.2, 32.1, 30.0, 29.9, 29.7,
29.5, 29.4, 29.3, 29.2, 27.4, 27.4, 26.1, 25.2, 25.1, 24.9, 22.9, 14.3.
MS (MALDI): 733.56 [M + Na]+. MALDI-HRMS: [M + Na]+
calcd for C41H75NaO7P, 733.5240; found, 733.5231.
2-Methoxy-1,2-oxaphosphorinane-4-O-oleoyl-5-hydroxy-2-
oxide (16) was obtained from 14 in 38% yield analogously as
described for compound 15. 1H NMR (400 MHz, CDCl3): δ 5.27
(t, J ) 5.6 Hz, 2H), 5.04 (d, J ) 10.4 Hz, 1H), 4.24 (dt, J ) 26.0,
12.0 Hz, 1H), 4.02 (d, J ) 12.0 Hz, 1H), 3.94 (s, 1H), 3.74 (s,
1H), 3.71 and 3.69 (s, 3H), 2.38 (m, 1H), 2.29 (t, J ) 7.6 Hz, 2H),
2.15 (m, 1H), 1.94 (d, J ) 5.2 Hz, 4H), 1.55 (t, J ) 6.4 Hz, 2H),
1.20 (s, 20H), 0.81 (t, J ) 6.8 Hz,3H). 31P NMR (162 MHz,
CDCl3): δ 25.22. 13C NMR (101 MHz, CDCl3): δ 173.0, 130.2,
129.9, 70.5, 69.2, 69.2, 66.4, 66.38, 52.0, 51.9, 34.5, 34.4, 32.1,
29.9, 29.88, 29.7, 29.5, 29.4, 29.3, 29.3, 27.4, 27.3, 25.0, 24.7, 23.5,
22.9, 14.3. MS (MALDI): 447.31 [M + H]+. MALDI-HRMS: [M
+ H]+ calcd for C23H44O6P, 447.2876; found, 447.2876.
2-Hydroxy-1,2-oxaphosphorinane-4,5-O-dipalmitoyl-2-ox-
ide (1). A suspension of Adams catalyst (PtO2, 40 mg, 0.18 mmol)
in 3 mL of MeOH was flushed with hydrogen, and a solution of
11 (42 mg, 0.058 mmol) in 2 mL of MeOH was added. After it
was stirred for 3 h at room temperature, the reaction mixture was
diluted with MeOH and filtered through Celite, Removal of the
solvent afforded 1 (27.8 mg, 74%) as a white solid. 1H NMR (400
MHz, CDCl3/CD3OD 1:1): δ 5.20 (m, 2H), 4.15 (t, J ) 12.8 Hz,
1H), 4.06 (t, J ) 11.4 Hz. 1H), 2.32 (t, J ) 7.2 Hz, 2H), 2.18 (t,
J ) 7.2 Hz, 2H), 2.12-1.98 (m, 2H), 1.57 (t, J ) 6.8 Hz, 2H),
1.50 (t, J ) 6.8 Hz, 2H), 1.18 (s, 48H), 0.79 (t, J ) 6.8 Hz, 6H).
31P NMR (162 MHz, CDCl3/CD3OD 1:1): δ 20.20. 13C NMR (101
MHz, CDCl3/CD3OD 1:1): δ 173.5, 173.2, 69.5, 67.8, 65.6, 34.3,
32.0, 29.8, 29.7, 29.66, 29.59, 29.5, 29.4, 29.2, 25.1, 24.8, 22.7,
13.9. MS (MALDI): 667.50 [M + Na]+. MALDI-HRMS: [M +
Na]+ calcd for C36H69NaO7P, 667.4609; found, 667.4601.
2-Hydroxy-1,2-oxaphosphorinane-4-O-palmitoyl-5-hydroxyl-
2-oxide (2) was obtained from 12 in 82% yield analogously as
1
described for compound 1. HNMR (400 MHz, CDCl3/CD3OD
2:1): δ 5.09-4.92 (m, 1H), 4.15-3.96 (m, 2H), 3.85 (s, 1H), 2.32
(dd, J ) 7.2, 3.6 Hz, 1H), 2.27 (t, J ) 7.6 Hz, 1H), 2.07(dt, J )
17.2, 12.8 Hz, 1H), 1.93 (m, 1H), 1.54 (t, J ) 7.2 Hz, 2H), 1.18 (s,
24H), 0.80 (t, J ) 6.8 Hz, 3H). 31P NMR (162 MHz, CDCl3/CD3-
OD 2:1): δ 20.96, 20.09. 13C NMR (101 MHz, CDCl3/CD3OD
2:1): δ 173.8, 72.0, 67.4, 66.9, 34.4, 32.1, 29.8, 29.7, 29.7, 29.6,
29.5, 29.4, 29.2, 24.9, 22.8, 14.0. MS (MALDI): 429.24 [M +
Na]+. MALDI-HRMS: [M + Na]+ calcd for C20H39NaO6P,
429.2382; found, 429.2381.
2-Methoxy-1,2-oxaphosphorinane-5-O-oleoyl-4-hydroxy-2-
oxide (17). Compound 17 was obtained from 14 in 12% yield
1
analogously as described for compound 15. HNMR (400 MHz,
CDCl3): δ 5.27 (s, 2H), 5.04 (s, 1H), 4.36 (m, 1H), 4.30-4.16
(m, 2H), 3.78 and 3.75 (s, 3H), 2.88 (br, 1H), 2.33 (t, J ) 7.6 Hz,
2H), 2.22-2.07 (m, 2H), 1.94 (d, J ) 4.4 Hz, 4H), 1.57 (s, 2H),
1.23 (s, 20H), 0.81 (t, J ) 6.8 Hz, 3H). 31P NMR (162 MHz,
CDCl3): δ 26.76. 13C NMR (101 MHz, CDCl3): δ 173.5, 130.3,
129.9, 70.1, 70.0, 66.8, 65.1, 65.0, 53.0, 52.9, 34.4, 32.1, 30.0, 29.9,
29.7, 29.5, 29.4, 29.3, 29.2, 28.5, 27.4, 27.4, 27.3, 25.1, 22.9, 14.3.
MS (MALDI): 447.30 [M + H]+. MALDI-HRMS: [M + H]+
calcd for C23H44O6P, 447.2876; found, 447.2870.
2-Hydroxy-1,2-oxaphosphorinane-4,5-O-dioleoyl-2-oxide (3).
To a solution of 15 (16 mg, 0.0225 mmol) in 1 mL of dry CH2Cl2
was added 0.2 mL of TMSBr. The mixture was stirred for 4 h, and
then the solvent was removed completely. To the residue was added
2 mL of MeOH and 2 drops of water, and after the mixture was
stirred for 1 h, the solvent was concentrated to afford product 3
(14 mg, 89%). 1HNMR (400 MHz, CDCl3): δ 5.32-5.20 (m, 6H),
4.23-4.14 (m, 2H), 2.32 (t, J ) 7.2 Hz, 2H), 2.23-2.17 (m, 4H),
1.94 (m, 8H), 1.55 (m, 4H), 1.23 (s, 40H), 0.81 (t, J ) 6.8 Hz,
2-Methoxy-3,6-dihydro-[1,2]oxaphosphinine-2-oxide (13). To
7 mL of MeOH was added n-BuLi (0.36 mL, 2.5 M in hexanes,
0.91 mmol) at -78 °C, and the solution was warmed to 0 °C over
2 h. Compound 9 (160 mg, 0.76 mmol) was added dropwise to
this solution in 7 mL of MeOH, and after the addition was
completed, the mixture was stirred for an hour at -5 °C. The
reaction mixture was quenched with a small amount of saturated
NH4Cl solution, MeOH and water were removed under reduced
pressure, and the residue was extracted with EtOAc and dried with
Na2SO4. Removal of the solvent and flash chromatography (EtOAc/
1
hexanes 2:1) afforded 13 (100 mg, 89%) as an oil. H NMR (400
MHz, CDCl3): δ 5.74-5.60 (m, 2H), 4.80-4.66 (m, 2H), 3.73
and 3.70 (s, 3H), 2.54-2.32 (m, 2H). 31P NMR (162 MHz,
CDCl3): δ 21.84. 13C NMR (101 MHz, CDCl3): δ 125.5, 125.3,
120.7, 120.6, 69.2, 69.1, 51.9, 51.88, 22.7, 21.4. MS (CI): 149.0
J. Org. Chem, Vol. 71, No. 16, 2006 6065

Zhang et al.
6H). 31P NMR (162 MHz, CDCl3): δ 26.03. 13C NMR (101 MHz,
CDCl3): δ 173.0, 172.6, 130.3, 130.2, 129.9, 34.4, 34.2, 32.1, 30.0,
29.95, 29.8, 29.6, 29.4, 29.4, 29.3, 29.27, 27.4, 27.4, 25.2, 24.9,
14.3. MS (MALDI): 719.50 [M + Na]+. MALDI-HRMS: [M +
Na]+ calcd for C40H73NaO7P, 719.4992; found, 719.4986.
CDCl3): δ 5.38-5.32 (m, 2H), 5.30-5.27 (m, 0.4H), 5.12-5.07
(m, 0.6H), 4.51-4.22 (m, 2H), 4.04-3.99 (m, 1H), 2.81-2.56 (m,
1H), 2.47-2.38 (m, 1H), 2.37-2.33 (m, 2H), 1.99 (m, 4H), 1.64
(m, 2H), 1.29 (m, 20H), 0.87 (t, J ) 6.8 Hz, 3H). 31P NMR (162
MHz, CDCl3): δ 24.53, 22.03. 13C NMR (101 MHz, CDCl3): δ
172.4, 130.3, 129.9, 70.8, 65.8, 45.8, 44.1, 34.4, 34.2, 32.1, 30.0,
29.9, 29.8, 29.6, 29.4, 29.3, 29.26, 27.5, 27.4, 25.0, 22.9, 14.4.
MALDI-HRMS: [M + Na]+ calcd for C22H41O6P, 455.2533; found,
455.2528.
2-Hydroxy-1,2-oxaphosphorinane-4-O-oleoyl-5-hydroxyl-2-
oxide (4). Compound 4 was obtained from 16 in 77% yield
1
analogously as described for compound 3. H NMR (400 MHz,
CDCl3): δ 8.35 (br, 1H), 5.38-5.32 (m, 2H), 5.30-5.24 (m, 0.4H),
5.12-5.07 (m, 0.6H), 4.53-4.22 (m, 2H), 4.06-3.99 (m, 1H),
2.81-2.56 (m, 1H), 2.47-2.39 (m, 1H), 2.39-2.33 (m, 2H), 1.99
(m, 4H), 1.63 (t, J ) 7.2 Hz, 2H), 1.30 (m, 20H), 0.87 (t, J ) 6.8
Hz, 3H). 31P NMR (162 MHz, CDCl3): δ 24.94, 22.42. 13C NMR
(101 MHz, CDCl3): δ 172.4, 130.3, 129.9, 71.1, 70.7, 65.8, 45.6,
43.9, 34.4, 34.2, 33.6, 32.1, 30.0, 29.9, 29.7, 29.5, 29.3, 29.29, 29.2,
27.4, 27.37, 25.0, 22.9, 14.4. MALDI-HRMS: [M + Na]+ calcd
for C22H41O6P, 455.2533; found, 455.2536.
Acknowledgment. We thank the NIH (Grant NS29632 to
G.D.P. and Grants HL61469 and CA921160 to G.T.) for
financial support of this work.
Supporting Information Available: General procedure and
selected 1H NMR, 31P NMR, and 13C NMR spectra for new
compounds in pdf format. This material is available free of charge
via the Internet at http://pubs.acs.org.
2-Hydroxy-1,2-oxaphosphorinane-5-O-oleoyl-4-hydroxyl-2-
oxide (5) Compound 5 was obtained from 17 in 61% yield
1
analogously as described for compound 3. H NMR (400 MHz,
JO0607919
6066 J. Org. Chem., Vol. 71, No. 16, 2006