One-pot, three-component synthesis of 5-(alkylimino)-2-(diethoxyphosphoryl) -2,5-dihydrofuran-3,4-dicarboxylates

Article abstract of DOI:10.1080/00397911.2010.519094

5-(Alkylimino)-2-(diethoxyphosphoryl)-2,5-dihydrofuran-3,4-dicarboxylates are prepared via a one-pot, three-component reaction of a-ketophosphonates, isocyanides, and dialkyl acetylenedicarboxylates at room temperature and neutral conditions. The structures of the products were deduced from their ¹H NMR, ¹³C NMR, and infrared spectra and mass spectrometry.

Full text of DOI:10.1080/00397911.2010.519094

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One-Pot, Three-Component
Synthesis of 5-(Alkylimino)-2-
(diethoxyphosphoryl)-2,5-
dihydrofuran-3,4-dicarboxylates
Javad Azizian a , Ali Ramazani b , Mohammad Haji a & Vahid
Azizkhani c
a Chemistry Department, Science and Research Branch, Islamic Azad
University, Tehran, Iran
b Department of Chemistry, Zanjan Branch, Islamic Azad University,
Zanjan, Iran
c Chemistry Department, Payame Noor University, Abhar, Zanjan,
Iran
Accepted author version posted online: 30 Jun 2011.Published
online: 09 Jun 2011.
To cite this article: Javad Azizian , Ali Ramazani , Mohammad Haji & Vahid Azizkhani (2011): One-
Pot, Three-Component Synthesis of 5-(Alkylimino)-2-(diethoxyphosphoryl)-2,5-dihydrofuran-3,4-
dicarboxylates, Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 41:24, 3609-3619
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Synthetic Communications1, 41: 3609–3619, 2011
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397911.2010.519094
ONE-POT, THREE-COMPONENT SYNTHESIS OF
5-(ALKYLIMINO)-2-(DIETHOXYPHOSPHORYL)-
2,5-DIHYDROFURAN-3,4-DICARBOXYLATES
Javad Azizian,1 Ali Ramazani,2 Mohammad Haji,1 and
Vahid Azizkhani3
1Chemistry Department, Science and Research Branch, Islamic Azad
University, Tehran, Iran
2Department of Chemistry, Zanjan Branch, Islamic Azad University,
Zanjan, Iran
3Chemistry Department, Payame Noor University, Abhar, Zanjan, Iran
GRAPHICAL ABSTRACT
Abstract 5-(Alkylimino)-2-(diethoxyphosphoryl)-2,5-dihydrofuran-3,4-dicarboxylates are
prepared via a one-pot, three-component reaction of a-ketophosphonates, isocyanides,
and dialkyl acetylenedicarboxylates at room temperature and neutral conditions. The struc-
tures of the products were deduced from their 1H NMR, 13C NMR, and infrared spectra
and mass spectrometry.
Keywords Alkyl isocyanide; dialkyl acetylenedicarboxylate; a-ketophosphonate;
2-phosphonofuran; three-component reaction
INTRODUCTION
Because of the unique properties of the phosphonic acid functional group,
phosphono-substituted heterocyclic systems are an important class of organopho-
sphorus compounds.[1] They are used in industrial chemistry to inhibit corrosion
or as complexing, emulsifying, and dispersing agents.[2] In pharmaceutical chemistry,
their enzyme inhibition, cytostatic, antiviral, antibacterial, antihypertensive, and
anti-inflammatory activities have been investigated.[3]
Received July 3, 2010.
Address correspondence to Javad Azizian, Chemistry Department, Science and Research Branch,
Islamic Azad University, P. O. Box 19395-1775, Tehran, Iran. E-mail: J_azizian@cc.sbu.ac.ir; or Ali
Ramazani, Department of Chemistry, Zanjan Branch, Islamic Azad University, P. O. Box 49195-467,
Zanjan, Iran. E-mail: aliramazani@gmail.com
3609

3610
J. AZIZIAN ET AL.
Figure 1. Some biologically active derivatives of 2-furanyl phosphonates.
2-Furylphosphonic acid derivatives are some of the most important biologi-
cally active heterocycles. Phosphonate prodrugs based on the furan ring are used
as antiviral agents in treatment of HSV (herpes simplex), HIV (human immuno-
deficiency virus) and HBV (hepatitis B virus) as well as to inhibit fructose-1,6-
bisphosphatase (FBPase) activity in treatment of type 2 diabetes (Fig. 1).[4]
With due attention to several studies on the synthesis of phosphono-
substituted heterocycles,[5] the most common synthetic methods for the preparation
of 2-furyl-phosphonates involve (a) 2-litiation of furan ring with BuLi and reaction
of the resulting 2-lithiofuran with dialkyl chlorophosphonate,[6] (b) reaction of
2-halofuran, 2-halo and 2-alkoxytetrahtdrofuran, 2-furaldehyde, 2-furoic acid, and
2-furanacrylic acid with trialkylphosphites in Arbuzov reaction condition,[7] and
(c) reaction of phosphonate anions with 5-halo-2-one compounds.[8] To the best of
our knowledge, there is no literature report of a multicomponent reaction involving
the use of a-ketophosphonates for the construction of a 2-furylphosphonate ring.
As part of our studies on the design of new routes for the preparation of
biologically active heterocyclic compounds and in continuation of our interest in
phosphorus chemistry and isocyanide-based multicomponent reactions,[9–37]
herein we report a facile method for synthesis of 2-phosphono-substituted furan
derivatives 4.
RESULTS AND DISCUSSION
Because of the strong electron-withdrawing effect of dialkyl phosphoryl
groups, the carbonyl in dialkyl a-keto phosphonates is highly electrophilic and
therefore reacts rapidly with all types of nucleophiles.[38] Recently, the reaction of
a-ketophosphonates with isocyanides in a Passerini manner was described by
Coffinier and his coworkers.[39] In this article, we describe the three-component reac-
tion of a-ketophosphonates 1, isocyanides 2, and dialkyl acetylenedicarboxylates 3 at
room temperature and in neutral conditions (Scheme 1).

SYNTHESIS OF 2-PHOSPHONOFURANS
3611
Scheme 1. Three-component synthesis of sterically congested 2-phosphono-substituted furan derivatives
4a–h.
A reasonable mechanism for this reaction based of isocyanide chemistry[40–42]
is proposed in Scheme 2. The formed zwitterionic intermediate under the influence of
isocyanide 2 and dialkyl acetylenedicarboxylates 3 smoothly reacts with a-keto phos-
phonate 1 at room temperature to afford 5-(alkylimino)-2-(diethoxyphosphoryl)-2-
,5-dihydrofuran-3,4-dicarboxylates 4. The structures of the final products 4a–h
were deduced from their elemental analyses, mass spectrometric data, and their
Scheme 2. Proposed mechanism for the formation of sterically congested 2-phosphono-substituted furan
derivatives 4a–h.

3612
J. AZIZIAN ET AL.
1H, 13C and 31P NMR and infrared (IR) spectra. The mass spectrum of 4a displayed
the molecular ion peak at m=z ¼ 432, which is consistent with the 1:1:1 adduct of
cyclohexyl isocyanide–dimethyl acetylenedicarboxylate–diethyl acetyl phosphonate.
The IR spectrum of 4a showed strong absorptions at 1766 and 1749 cmꢀ1 due to
the two ester carbonyls, and at 1685 and 1261 cmꢀ1 due to the C N and P O
respectively.
=
=
1
The H NMR spectra of 4a exhibited two singlets for MeO groups (d ¼ 3.72
3
and 3.76 ppm), a doublet for C-2 methyl (d ¼ 1.76 ppm, JHP ¼ 14.7 Hz), and three
multiplets for cyclohexyl and phosphonate methyl protons (d ¼ 1.0–1.9 ppm),
N-CH (d ¼ 3.49 ppm), and phosphonate methylene protons (d ¼ 3.9–4.20 ppm).
The 1H-decoupled 13C NMR spectrum of 4a showed 18 distinct signals, in agreement
with the proposed structure, and partial assignment of these resonances is given in
the Experimental section. The 31P NMR spectrum of 4a showed one signal at
d ¼ 13.15 ppm.
The 1H, 13C, and 31P NMR spectra of compounds 4b–h were similar to those of
4a, except for the signals of the C-2 alkyl or aryl substituents and the alkyl substitu-
ents of alkylamino and carboxylate moieties, which exhibited characteristic signals
with appropriate chemical shifts.
CONCLUSION
In summary, the reported method offers a mild, simple, and efficient route
for the preparation of sterically congested 2-phosphonofuran derivatives 4 from a-
ketophosphonates 1, isocyanides 2, and dialkyl acetylenedicarboxylates
3
(Scheme 1). Its ease of workup, good yields, and fairly mild reaction conditions make
it a useful addition to modern synthetic methodologies.
EXPERIMENTAL
Starting materials and solvents were obtained from Merck (Germany) and
Fluka (Switzerland) and were used without further purification. IR spectra were
measured on a Shimadzu IR-460 spectrometer. 1H NMR, 13C NMR, and 31P
NMR spectra were measured (CDCl3 solution) with a Bruker DRX-250 Avance
spectrometer at 250.0, 62.9, and 101.2 MHz, respectively. Mass spectra were recor-
ded on an Agilent Technologies (HP) 5973 mass spectrometer operating at an
ionization potential of 70 eV. Elemental analyses were performed using a Heraeus
CHN-O-Rapid analyzer. Chromatography columns were prepared from Merck
silica-gel powder.
General Procedure
A solution of 0.166 g triethylphosphite (1 mmol) in 5 cm3 CH2Cl2 was added
dropwise at 0 ꢁC to a magnetically stirred solution of 1 mmol acyl chloride 1 in
dry CH2Cl2 (5 cm3) over 15 min. The mixture was then allowed to warm to rt and
stirred for 30 min. Then the mixture was cooled to 0 ꢁC, and 1 mmol dialkyl acetyle-
nedicarboxylate 3 was added. A solution of 1 mmol isocyanide 2 in dry CH2Cl2
(2 cm3) was added dropwise to this mixture over 15 min. The mixture was stirred

SYNTHESIS OF 2-PHOSPHONOFURANS
3613
for 24 h. The solvent was evaporated, and the residue was purified by flash column
chromatography (silica gel, Petroleum ether=AcOEt 3:1). The characterization data
of the compounds are given.
Selected Data
Dimethyl
5-(cyclohexylimino)-2-(diethoxyphosphoryl)-2-methyl-2,5-
dihydrofuran-3,4-dicarboxylate (4a). Yellow viscous oil; yield 0.29 g (67%); IR
(thin film) (vmax, cmꢀ1): 2955, 1766, 1749, 1685, 1472, 1261, 1025; 1H NMR
(250 MHz, CDCl3) dH: 1.0–1.9 (m, 2Me and 5CH2 of cyclohexyl, 1.76 (d,
3JHP ¼ 14.7 Hz, Me), 3.49 (m, CH-N), 3.72 (s, MeO), 3.76 (s, MeO), 3.90–4.20 (m,
3
2CH2OPO); 13C NMR (62.9 MHz, CDCl3) dC: 16.20 (d, JCP ¼ 6.3 Hz, Me), 16.29
3
(d, JCP ¼ 6.3 Hz, Me), 20.38 (Me), 24.60, 25.55, 33.11 and 33.34 (5CH2 of cyclo-
2
hexyl), 52.66 and 52.82 (2MeO), 56.29 (CH-N), 63.80 (d, JCP ¼ 6.9 Hz, CH2OPO),
2
1
64.06 (d, JCP ¼ 7.5 Hz, CH2OPO), 87.17 (d, JCP ¼ 167.9 Hz, C), 135.27 (d,
=
JCP ¼ 8.2 Hz, C-alkene), 145.12 (C-alkene), 153.76 (C N), 161.08 and 161.63
(2C O); 31P NMR (101.2 MHz, CDCl3) dP: 13.15; MS (m=z, %): 432 (Mþ þ 1,
=
100), 351 (17), 293 (95), 262 (65), 212 (30), 180 (40), 155 (16), 138 (24), 109 (38),
81 (47), 43 (72). Anal. calcd. for C19H30NO8P (431.42): C, 52.89; H, 7.01; N, 3.24.
Found: C, 53.11; H, 7.18; N, 3.41%.
Diethyl
5-(cyclohexylimino)-2-(diethoxyphosphoryl)-2-methyl-2,5-
dihydrofuran-3,4-dicarboxylate (4b). Yellow viscous oil; yield 0.29g (63%); IR
(thin film) (vmax, cmꢀ1): 2934, 1792, 1734, 1683, 1447, 1265, 1027; 1H NMR
(250MHz, CDCl3) dH: 1.1–2.0 (m, 4Me and 5CH2 of cyclohexyl), 1.91 (d,
3JHP ¼ 14.7 Hz, Me), 3.85 (m, CH-N), 4.1–4.5 (m, 2CH2OPO and 2CH2O); 13C
3
NMR (62.9 MHz, CDCl3) dC: 13.85 and 13.95 (2Me), 16.25 (d, JCP ¼ 6.3 Hz, Me),
16.6 (d, 3JCP ¼ 6.2 Hz, Me), 20.06 (Me), 24.69, 25.75, 32.60 and 33.32 (5CH2 of cyclo-
2
hexyl), 56.37 (CH-N), 62.43 and 62.84 (2CH2O), 64.69 (d, JCP ¼ 7.8 Hz, CH2OPO),
2
1
64.93 (d, JCP ¼ 7.8, CH2OPO), 84.24 (d, JCP ¼ 152.5 Hz, C), 134.20 and 141.24
(C-alkene), 159.33 (C N), 160.21 and 160.50 (2C O); 31P NMR (101.2MHz, CDCl3)
dP: 13.29 ppm; MS (m=z, %): 459 (Mþ, 1), 379 (100), 335 (19), 196 (77), 168 (97), 127
(37), 99 (41), 81 (36), 43 (95). Anal. calcd. for C21H34NO8P (459.48): C, 54.89; H, 7.46;
N, 3.05. Found: C, 55.12; H, 7.53; N, 3.17%.
=
=
Dimethyl 5-(cyclohexylimino)-2-(diethoxyphosphoryl)-2-phenyl-2,5-
dihydrofuran-3,4-dicarboxylate (4c). Pale yellow viscous oil; yield 0.28 g (56%);
1
IR (thin film) (vmax, cmꢀ1): 2986, 1795, 1747, 1683, 1438, 1275, 1026; H NMR
3
(250 MHz, CDCl3) dH: 0.9–2.1 (m, 5CH2 of cyclohexyl), 1.14 (t, JHH ¼ 7.2 Hz,
3
Me), 1.31 (t, JHH ¼ 7.0 Hz, Me), 3.76 (m, CH-N), 3.88 and 3.89 (s, 2MeO),
4.00–4.32 (m, 2CH2OPO), 7.30–7.70 (m, 5H, aromatic); 13C NMR (62.9 MHz,
3
3
CDCl3) dH: 16.14 (d, JCP ¼ 5.7 Hz, Me), 16.28 (d, JCP ¼ 5.7 Hz, Me), 24.76,
25.59, 33.25 and 33.48 (5CH2 of cyclohexyl), 53.16 and 53.42 (2MeO), 56.85
2
2
(CH-N), 65.25 (d, JCP ¼ 6.9 Hz, CH2OPO), 65.60 (d, JCP ¼ 7.5 Hz, CH2OPO),
1
90.24 (d, JCP ¼ 164.0 Hz, C), 126.21, 128.71, 129.62 and 130.73 (C-Ar), 136.10
and 147.31 (C-alkene), 159.10 (C N), 160.30 and 161.20 (2C O); 31P NMR
=
=
(101.2 MHz, CDCl3) dP: 9.97; MS (m=z, %): 493 (Mþ, 1), 412 (41), 358 (11), 275

3614
J. AZIZIAN ET AL.
(15), 244 (85), 217 (15), 105 (100), 77 (70), 51 (16). Anal. calcd. for C24H32NO8P
(493.49): C, 58.41; H, 6.54; N, 2.84. Found: C, 58.57; H, 6.71; N, 2.96%.
Diethyl 5-(cyclohexylimino)-2-(diethoxyphosphoryl)-2-phenyl-2,5-
dihydrofuran-3,4-dicarboxylate (4d). Pale yellow viscous oil; yield 0.29 g (55%);
1
IR (thin film) (vmax, cmꢀ1): 2984, 1797, 1743, 1685, 1449, 1267, 1028; H NMR
(250 MHz, CDCl3) dH: 1.10–1.90 (m, 4Me and 5 CH2 of cyclohexyl), 3.74 (m,
CH-N), 3.90–4.40 (m, 2CH2OPO and 2CH2O), 7.21–7.80 (m, 5H, aromatic); 13C
3
NMR (62.9 MHz, CDCl3) dC: 13.32 and 13.41 (2Me), 16.22 (d, JCP ¼ 5.7 Hz,
3
Me), 16.34 (d, JCP ¼ 5.7 Hz, Me), 24.67, 25.70, 33.39 and 33.51 (5CH2 of cyclo-
hexyl), 56.58 (CH-N), 62.40 and 62.84 (2CH2O), 65.17 (d, 2JCP ¼ 7.3 Hz, CH2OPO),
2
1
65.50 (d, JCP ¼ 7.5 Hz, CH2OPO), 90.05 (d, JCP ¼ 165.7 Hz, C), 126.80, 128.24,
=
129.32 and 130.88 (C-Ar), 135.12 and 145.65 (C-alkene), 159.14 (C N), 160.56
and 161.08 (2C O); 31P NMR (101.2 MHz, CDCl3) dP: 12.49; MS (m=z, %): 522
=
(Mþ þ 1, 51), 441 (48), 385 (35), 334 (31), 302 (42), 258 (95), 212 (43), 135 (65),
105 (100), 77 (50). Anal. calcd. for C26H36NO8P (521.54): C, 59.88; H, 6.95; N,
2.68. Found: C, 59.74; H, 7.11; N, 2.84%.
Dimethyl 2-(diethoxyphosphoryl)-2-methyl-5-[(1,1,3,3-tetramethylbu-
tylimino)]-2,5-dihydrofuran-3,4-dicarboxylate (4e). Yellow viscous oil; yield
0.29 g (60%); IR (thin film) (vmax, cmꢀ1): 2955, 1748, 1679, 1619, 1438, 1263, 1022;
3
1H NMR (250 MHz, CDCl3) dH: 0.96 (s, Me3C), 0.99 (t, JHH ¼ 6.25 Hz, Me),
3
3
1.31 and 1.41 (2 Me), 1.35 (t, JHH ¼ 6.50 Hz, Me), 1.94 (d, JHP ¼ 15.0 Hz, Me),
2
2
1.90 (d, JHH ¼ 17.5 Hz, CH), 2.03 (d, JHH ¼ 17.5 Hz, CH), 3.80 and 3.82
(2MeO), 4.11–4.31 (m, 2CH2OPO) ppm; 13C NMR (62.9 MHz, CDCl3) dC: 16.32
3
3
(d, JCP ¼ 5.7 Hz, Me), 16.41 (d, JCP ¼ 5.6 Hz, Me), 22.50, 29.37 and 30.23 (3Me),
31.36 (Me3C), 31.58 (CMe3), 50.78 (CH2), 52.74 and 54.11 (2MeO), 56.70
2
2
(Me2C-N), 63.90 (d, JCP ¼ 6.7, CH2OPO), 64.10 (d, JCP ¼ 6.8, CH2OPO), 88.10
1
=
(d, JCP ¼ 165.6, C), 134.20 and 141.50 (C-alkene), 156.30 (C N), 164.00, 166.50
(2C O) ppm; 31P NMR (101.2 MHz, CDCl3) dP: 15.20 ppm; MS (m=z, %): 462
=
(Mþ þ 1, 5), 429 (48), 385 (19), 196 (77), 168 (97), 127 (37), 99 (41), 81 (36), 43
(95). Anal. calcd. for C21H36NO8P (461.49): C, 54.65; H, 7.86; N, 3.03. Found: C,
54.82; H, 7.73; N, 3.14%.
Diethyl 2-(diethoxyphosphoryl)-2-methyl-5-[(1,1,3,3-tetramethylbutyli-
mino)]-2,5-dihydrofuran-3,4-dicarboxylate (4f). Yellow viscous oil; yield 0.28 g
(57%); IR (thin film) (vmax, cmꢀ1): 2983, 1734, 1678, 1620, 1446, 1265, 1024;
1H NMR (250 MHz, CDCl3) dH: 0.90–1.10 (m, Me and Me3C), 1.20–1.47 (m,
2
2
3Me), 1.52 (d, JHH ¼ 14.5 Hz, CH), 1.64 (d, JHH ¼ 14.5 Hz, CH), 1.89 (d,
3JHP ¼ 14.5 Hz, Me), 4.11–4.42 (m, 2CH2OPO and 2CH2O); 13C NMR (62.9 MHz,
3
3
CDCl3) dC: 13.84 and 13.97 (2 Me), 16.38 (d, JCP ¼ 6.0, Me), 16.46 (d, JCP ¼ 5.7,
Me), 20.63, 29.45 and 30.30 (3Me), 31.42 (Me3C), 31.62 (CMe3), 53.25 (CH2),
2
55.36 (Me2C-N), 59.27 and 60.63 (2CH2O), 63.62 (d, JCP ¼ 6.2 Hz, CH2OPO),
2
1
63.92 (d, JCP ¼ 6.3 Hz, CH2OPO), 86.4 (d, JCP ¼ 162.8 Hz, C), 136.70 and 143.60
(C-alkene), 157.40 (C N), 159.27 and 161.30 (2C O); 31P NMR (101.2 MHz,
CDCl3) dP: 15.26; MS (m=z, %): 490 (Mþ þ 1, 5), 443 (87), 405 (10), 379 (32), 331
(90), 196 (35), 168 (41), 149 (57), 109 (21), 43 (75). Anal. calcd. for C23H40NO8P
(489.55): C, 56.43; H, 8.23; N, 2.86. Found: C, 56.61; H, 8.41; N, 3.00%.
=
=

SYNTHESIS OF 2-PHOSPHONOFURANS
3615
Diemthyl 2-(diethoxyphosphoryl)-2-phenyl-5-[(1,1,3,3-tetramethylbuty-
limino)]-2,5-dihydrofuran-3,4-dicarboxylate (4g). Pale yellow viscous oil; yield
0.3 g (54%); IR (thin film) (vmax, cmꢀ1): 2954, 1765, 1747, 1678, 1473, 1261, 1024;
3
1H NMR (250 MHz, CDCl3) dH: 0. 9 (t, JHH ¼ 7.0 Hz, Me), 1.07 (s, Me3C), 1.32
3
2
(t, JHH ¼ 7.0 Hz, Me), 1.54 (s, Me2C), 1.64 (d, JHH ¼ 15 Hz, CH), 1.97 (d,
2JHH ¼ 15 Hz, CH), 3.75 and 3.84 (s, 2MeO), 4.10–4.30 (m, 2CH2OPO), 7.41–7.76
(m, 5H, Aromatic); 13C NMR (62.9 MHz, CDCl3) dC: 16.11 (d, JCP ¼ 5.8 Hz,
3
3
Me), 16.34 (d, JCP ¼ 6.2 Hz, Me), 29.80 and 30.84 (2 Me), 31.5 (Me3C), 31.64
(CMe3), 50.80 (CH2), 54.13 (Me2C-N), 54.35 and 56.85 (2MeO), 63.96 (d,
2JCP ¼ 7.3 Hz, CH2OPO), 64.41 (d, 2JCP ¼ 7.2 Hz, CH2OPO), 90.24 (d,
1JCP ¼ 165.2 Hz, C), 126.12, 128.25, 128.68 and 129.52 (4C, aromatic), 134.27 and
144.16 (C-alkene), 155.60 (C N), 161.10 and 161.30 (2C O); 31P NMR
(101.2 MHz, CDCl3) dP: 13.51; MS (m=z, %): 523 (Mþ, 1), 491 (51), 379 (100),
347 (20), 242 (30), 211 (36), 105 (32), 57 (20). Anal. calcd. for C26H38NO8P
(523.56): C, 59.65; H, 7.32; N, 2.67. Found: C, 59.74; H, 7.21; N, 2.81%.
=
=
Diethyl 2-(diethoxyphosphoryl)-2-phenyl-5-[(1,1,3,3-tetramethylbutyl-
imino)]-2,5-dihydrofuran-3,4-dicarboxylate (4h). Pale yellow viscous oil; yield
0.29 g (52%); IR (thin film) (vmax, cmꢀ1): 2983, 1734, 1678, 1446, 1264, 1024 cmꢀ1
;
3
1H NMR (250 MHz, CDCl3) dH: 0.9 (t, JHH ¼ 7.0 Hz, Me), 1.07 (s, Me3C), 1.20
3
3
3
(t, JHH ¼ 7.2 Hz, Me), 1.31 (t, JHH ¼ 7.5 Hz, Me), 1.43 (t, JHH ¼ 7.2 Hz, Me),
2
2
1.54 (s, Me2C), 1.63 (d, JHH ¼ 15 Hz, CH), 1.98 (d, JHH ¼ 15 Hz, CH), 3.80–4.50
(m, 2CH2O, 2CH2OPO), 7.40–7.80 (m, 5H, aromatic); 13C NMR (62.9 MHz,
3
CDCl3) dC: 13.90 and 14.41 (2Me), 16.07 (d, JCP ¼ 6.3 Hz, Me), 16.21 (d,
3JCP ¼ 6.1 Hz, Me), 29.74 and 30.26 (2Me), 31.64 (Me3C), 31.88 (CMe3), 53.10
(Me2C), 55.61 and 58.26 (2CH2O), 61.82 (CH2), 63.91 (d, 2JCP ¼ 6.9 Hz, CH2OPO),
2
1
64.23 (d, JCP ¼ 6.3 Hz, CH2OPO), 90.41 (d, JCP ¼ 165.4 Hz, C), 126.86, 128.74,
=
129.36, 134.21 (4C, aromatic), 135.23 and 142.32 (C-alkene), 150.61 (C N),
160.44 and 161.65 (2C O); 31P NMR (101.2 MHz, CDCl3) dP: 13.53; MS (m=z,
=
%): 552 (Mþ þ 1, 10), 505 (100), 393 (92), 256 (17), 211 (50), 105 (56), 77 (15), 57
(31), 41 (15). Anal. calcd. for C28H42NO8P (551.61): C, 60.97; H, 7.67; N, 2.54.
Found: C, 61.11; H, 7.78; N, 2.70%.
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1. (a) Walker, B. J. Quinquevalent phosphorus acids; In Organophosphorus Chemistry; D.
W. Allen, J. C. Tebby, (Eds.); Royal Society of Chemistry: Cambridge, 2001; vol. 31;
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