Synthesis and cyclization of diethylphosphono-substituted α-allenic alcohols to 4-(diethylphosphono)-2,5-dihydrofurans

Article abstract of DOI:10.1055/s-1999-3420

Various types of diethylphosphono-substituted α-allenic alcohols have been readily prepared. Treatment of these compounds with a catalytic amount of silver nitrate under a nitrogen atmosphere provided the corresponding 4- (diethylphosphono)-2,5-dihydrofurans.

Full text of DOI:10.1055/s-1999-3420

PAPER
463
Synthesis and Cyclization of Diethylphosphono-Substituted α-Allenic Alcohols
to 4-(Diethylphosphono)-2,5-dihydrofurans
Valery K. Brel
Institute of Physiologically Active Compounds of Russian Academy of Science, Chernogolovka, Moscow region, 142432, Russia
Fax +7(95)9132113; E-mail: brel@ipac.ac.ru
Received 13 August 1998
Abstract: Various types of diethylphosphono-substituted α-allenic
alcohols have been readily prepared. Treatment of these com-
pounds with a catalytic amount of silver nitrate under a nitrogen
atmosphere provided the corresponding 4-(diethylphosphono)-2,5-
dihydrofurans.
Key words: cyclization, furans, phosphaallenes, phosphorus hete-
rocycles
Allenes have been widely used as building blocks in or-
ganic chemistry for construction of five and six-mem-
bered carbocyclic and heterocyclic ring systems.1,2 An
impressive number of heterocyclic systems has been pre-
pared from allenic starting materials or via allenes as un-
stable intermediates.3Ð6 Several examples of cyclization of
allenic alcohols to derivatives 2,5-dihydrofurans have
been described.7Ð10
Application of this approach to phosphorus-containing al-
lenes had opened the way to 4-(diethylphosphono)-2,5-di-
hydrofurans. In order to investigate the scope and
Scheme
limitations of the new approach and synthetic strategies
for synthesis of phosphorus-containing heterocyclic com-
pounds,1c,11,12 we have synthesized and studied interaction
of several γ,γ-disubstituted allenylphosphonic acid deriv-
atives having different substituents on the allenic system
with silver nitrate. In this paper we would like to report
our findings on the intramolecular cyclization of dieth-
ylphosphono-substituted α-allenic alcohols. Our aim was
to synthesize 2,2-dialkyl-4-(diethylphosphono)-2,5-di-
hydrofurans 4aÐf, new phosphonic heterocycles.
anol solution of the reaction mixture in the presence of
HCl, at room temperature. Analytically pure phosphoryl-
ated allenes 3aÐf were isolated as colorless or pale yellow
oils by column chromatography on silica gel.
Treatment of the γ,γ-disubstituted phosphorylated allenic
alkohols 3aÐf with a catalytic amount of silver nitrate in
water/acetone led to complete cyclization, affording the
2,5-dihydrofurans 4aÐf within 0.5 h at 50Ð52¡C. Reac-
tions were monitored by TLC on SiO2; detection was
made using a KMnO4 basic solution and 1H NMR spectral
data. All of the 4-(diethylphosphono)-2,5-dihydrofurans
were isolated as stable colorless oils by column chroma-
tography on silica gel.
The 4-(diethylphosphono)-2,5-dihydrofurans 4aÐf were
synthesized by a simple and efficient three-step proce-
dure: synthesis of the alkynols 1aÐf; synthesis of the phos-
phorylated allenes 2aÐf; and cyclization of α-allenic
alcohols 3aÐf (Scheme).
Compounds 3aÐf and 4aÐf were identified by IR, 1H, 13C,
31P and MS spectral data. For example, IR spectra of all
compounds 3aÐf contained absorption bands of the phos-
phoryl group at 1249Ð1259 cmÐ1, the allenic system dou-
ble bonds at 1948Ð1960 cmÐ1 and hydroxy group 3610Ð
3593 cmÐ1. The 1H NMR spectrum of the phosphorylated
allenes 3aÐf contained signals of the protons for ethoxy
groups and for groups connected to the allenic system.
The chemical shift of phosphorus for 3aÐf, δP = 16Ð
18.1 ppm was characteristic for derivatives of phosphory-
The acetylenic alcohols 1aÐf were prepared in 60Ð70%
yield by a standard procedure starting from propargyl al-
cohol.11 Phosphorylated allenes 3aÐf were prepared di-
rectly from alcohols 1aÐf in 60Ð80% yields by HornerÐ
Mark [2,3]-sigmatropic rearrangement of the unstable
phosphites generated in situ by reaction with diethyl chlo-
rophosphite in the presence of triethylamine in diethyl
ether at Ð40¡C and then kept at 20¡C. Compounds 2aÐf
were stable enough to be handled at ambient temperature.
The hydroxyl group was deprotected by stirring the meth-
Synthesis 1999, No. 3, 463–466 ISSN 0039-7881 © Thieme Stuttgart á New York

464
V. K. Brel
PAPER
lated allenes.7,11,12c The extremely low-field position of
the allenic central carbon atom resonance (near 200 ppm
relative to tetramethylsilane) allows the immediate identi-
fication of the allenic moiety by 13C NMR spectroscopy.13
The chemical shift of signals of the allenic central carbon
atom for phosphorylated allenes 3aÐf is δ = 204Ð207 ppm.
ture was cooled in an ice bath, then acetone (1.22 g, 0.021 mol) in
Et2O (5 mL) was added dropwise over 15 min. The mixture was
then stirred and heated to reflux for additional 1h. The mixture was
cooled and sat. aq NH4Cl was added carefully to dissolve the solid
components. The two layers were separated and the aqueous phase
was extracted with Et2O (3 × 30 mL). The combined organic frac-
tions were dried (K2CO3) and solvent was evaporated in vacuo. The
crude acetylene 1a (2.53 g, 0.013 mol) was dissolved in Et2O
(50 mL) under N2, Et3N (1.52 g, 0.015 mol) was added and the mix-
ture was cooled to Ð50 oC. The solution of diethyl chlorophosphite
(2.03 g, 0.013 mol) in Et2O (10 mL) was added dropwise over
The mass spectra of the phosphorylated allenic alcohols
3aÐf contained signal of molecular ion M+ (intensity
about 10%).
o
20 min. The mixture was then stirred at Ð50 C over 1h and at r.t.
The structure of 4aÐf was clearly assigned by NMR spec-
tral data. NMR spectra of 4aÐf were in good agreement
with NMR spectral data for phenyl[2,2-dimethyl-4-(di-
ethylphosphono)-2,5-dihydro-3-furyl]iodonium salts.1c
For instance, the 1H NMR spectrum of the 4-(di-
ethylphosphono)-2-methyl-2-vinyl-2,5-dihydrofuran (4d)
contained a set of resonances characteristic of the CH3,
CH=CH2, (RO)2P(O)C=CH and (RO)2P(O)CCH2O
groups. The chemical shift of phosphorus, δp = 12.10Ð
13.12 ppm, is characteristic for compounds with a 4-coor-
dinate phosphorus atom linked with an sp2-hybridized
carbon atom.
for 5 h. The solid was removed by filtration and the solvent was
evaporated in vacuo. The crude phosphorylated allene 2a (2.39 g,
0.0078 mol) was dissolved in CH3OH (20 mL) and 35% of HCl (1Ð
2 drops) was added. The solution was stirred at r.t. over 30 min, and
the solvent was evaporated in vacuo. The crude product was chrom-
atographed on a silica gel column with Et2O/acetone (1:1) as eluent
to give 3a (1.83 g, 60%).
1H NMR (CDCl3): δ = 1.34 (6H, dt, J = 0.6, 7.0 Hz, 2CH3), 1.8 (6H,
d, J = 7.6 Hz, 2CH3), 3.8 (1H, br s, OH), 4.10 (4H, dq, J = 7.0, 6.8
Hz, 2CH2OP), 4.24 (2H, d, J = 14.0 Hz, CH2OH).
13C NMR[CD3C(O)CD3]: δ = 16.57 (d, JcÐp = 6.4 Hz), 19.61 (d,
JcÐp = 7.2 Hz), 60.63 (d, JcÐp = 12.0 Hz), 62.62 (d, JcÐp = 6.4 Hz),
94.16 (d, JcÐp = 184.7 Hz), 99.07 (d, JcÐp = 15.26 Hz), 207.08 (d,
JcÐp = 4.8 Hz).
In summary, we have described an easy and convenient
synthesis of the 2,2-dialkyl-4-(diethylphosphono)-2,5-di-
hydrofurans 4aÐf. Compounds 4aÐf and allenes 3aÐf have
been highlighted as interesting building blocks which,
hopefully, can be used in the synthesis of molecules of bio-
logical and pharmaceutical interest. Future studies on this
potentially important synthetic methodology are currently
in progress. Applications of phosphorylated allenes to the
synthesis of interesting phosphonic heterocycles will be
reported in due course.
31P NMR (CDCl3): δ = 18.50.
IR (film): ν = 1254 (P=O), 1950 (C=C=C), 3621 (OH).
MS: m/z (%) = 234(M+,10), 204(81), 169(25), 148(100), 133(12),
123(48), 99(35), 81(73), 65(48).
Calcd for C10H19PO4: C; 51.28%, H; 8.12%, P; 13.25%. Found: C;
51.33%, H; 8.20%, P; 13.18%.
5-Chloro-2-(diethylphosphono)-4-methylpenta-2,3-dien-1-ol (3b)
yield 67%.
1H NMR (CDCl3): δ = 1.35 (6H, dt, J = 1.0, 7.8 Hz, 2CH3), 1.92
(3H, d, J = 7.0 Hz, CH3), 3.3 (1H, br s, OH), 4.11 (6H, m, 2CH2OP,
CH2Cl), 4.28 (2H, d, J = 13.75 Hz, CH2OH).
NMR spectra were recorded on a Bruker CXP-200 spectrometer at
200 MHz (1H NMR), 81.01 MHz (31P NMR) and 50.3 MHz (13C
NMR). Chemical shifts for 1H NMR and 13C NMR are reported in
ppm relative to TMS as internal standard. 31P downfield shifts (δ)
are expressed with a positive sign, relative to external 85% H3PO4
in H2O. LRMS were measured on a Finnigan INCOS-50 system
(ionization voltage 70 eV). Significant fragments are reported as
follows: m/z [intensity relative to base (100)]. Infrared spectra were
recorded on a Bruker IFS-113 spectrometer. Samples were typically
prepared as films or in CCl4 solution. Band frequencies (ν) are re-
ported in (cmÐ1).
13C NMR[CD3C(O)CD3]: δ = 15.84 (d, JcÐp = 6.4 Hz), 16.57 (d, JcÐp
=
6.4 Hz), 47.26 (d, JcÐp = 6.4Hz), 60.37 (d, JcÐp = 11.2 Hz), 63.20 (d,
JcÐp = 6.5 Hz), 97.36 (d, JcÐp = 183.1 Hz), 101.37 (d, JcÐp = 14.5 Hz),
206.79 (d, JcÐp = 4.8 Hz).
31P NMR (CDCl3): δ = 16.07.
IR (film): ν = 1250 (P=O), 1955 (C=C=C), 3611 (OH).
MS: m/z (%) = 233(78), 203(100), 175(60), 159(28), 147(70),
127(53), 81(60), 65(30).
Column chromatography on silica gel was performed with Fluka
Silica gel 60 (0.035Ð0.070 mm) Preparative TLC was performed
on Fluka Silica gel/TLC-cards (20 × 20 × 0.2 cm). All reagents
were of commercial quality or were purified before use. Organic
solvents were purified and dried by standard procedures. The de-
tails of the preparation of 1 have been described in the earlier ar-
ticles.11 Propargyl alcohol was protected by reaction with ethyl
vinyl ether to afford the ether in nearly quantitative yield by stan-
dard procedures.14
Calcd for C10H18ClPO4: C; 44.69%, H; 6.70%, Cl; 13.22%, P;
11.55%. Found: C; 44.76%, H; 7.30%, Cl; 13.01%, P; 11.41%.
2-(Diethylphosphono)-4-methylpenta-2,3-diene-1,5-diol (3c)
yield 62%.
1H NMR (CDCl3): δ = 1.34 (6H, dt, J = 1.0, 8.0 Hz, 2CH3), 1.78
(3H, d, J = 7.6 Hz, CH3), 4.04 (2H, d, J = 12.0 Hz, CH2OH), 4.10
(4H, m, 2CH2OP), 4.14 (2H, d, J = 12.8 Hz, CH2OH), 4.34 (2H, br
s, 2OH).
13C NMR (CD3C(O)CD3): δ = 14.88 (d, JcÐp = 6.8 Hz), 16.50 (d,
JcÐp = 6.8 Hz), 60.45 (d, JcÐp = 12.2 4Hz), 63.18 (d, JcÐp = 6.5 Hz),
63.41 (d, JcÐp = 6.5 Hz), 96.39 (d, JcÐp = 184.5 Hz), 105.05 (d, JcÐp
15.0 Hz), 205.00 (d, JcÐp = 5.4 Hz).
31P NMR (CDCl3) δ = 17.8.
Phosphorylated Allenes 3aÐf
2-(Diethylphosphono)-4-methylpenta-2,3-dien-1-ol (3a); Typi-
cal Procedure
To a solution of EtMgBr (2.66 g, 0.02 mol) in anhyd Et2O (50 mL)
was added dropwise over 30 min at Ð5¡C, O-protected propargyl al-
cohol (2.56 g, 0.02 mol). The mixture was then stirred at r.t. for 1 h
and at 34¡C for 2 h. After the evolution of ethane ceased, the mix-
=
IR (film): ν = 1259 (P=O), 1942 (C=C=C), 3655 (OH).
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PAPER
Synthesis and Cyclization of Diethylphosphono-Substituted α-Allenic Alcohols
465
MS: m/z (%) 250(M+,12), 220(100), 203(45), 191(10), 175(30),
146(83), 129(23), 109(28), 92(40), 81(48), 65(40).
Phosphorylated 2,5-Dihydrofurans 4aÐf
4-(Diethylphosphono)-2,2-dimethyl-2,5-dihydrofuran (4a);
Typical Procedure
Calcd for C10H19PO5: C; 48.00%, H; 7.60%, P; 12.40%. Found: C;
48.27%, H; 7.54%, P; 12.13%.
To a 30 mL round-bottomed flask equipped with a reflux condenser
and a magnetic stirring bar was added silver nitrate (0.425 g,
0.0025 mol). The flask was flushed with N2, and an acetone/water
(4:1) mixture (8 mL) was introduced. To the mixture was added 3a
(1.17 g, 0.005 mol) and the solution was heated to reflux for 0.5 h.
Reactions were monitored by TLC on silica gel; detection was made
2-(Diethylphosphono)-4-methylhexa-2,3,5-trien-1-ol (3d)
yield 71%.
1H NMR (CDCl3): δ = 1.37 (6H, dt, J = 1.3, 7.6 Hz, 2CH3), 1.93
(3H, d, J = 7.5 Hz, CH3), 3.4 (1H, br s, OH), 4.14 (4H, m, 2CH2OP),
4.31 (2H, d, J = 14.0 Hz, CH2OH) 5.19 (2H, m, =CH2), 6.35 (1H,
m, =CH).
13C NMR[CD3C(O)CD3]: δ = 14.07 (d, JcÐp = 6.4 Hz), 16.36 (d,
JcÐp = 6.4 Hz), 61.44 (d, JcÐp = 12.0 Hz), 62.88 (d, JcÐp = 6.5 Hz),
93.77 (d, JcÐp = 183.8 Hz), 103.65 (d, JcÐp = 16.0 Hz), 115.40 (d,
JcÐp = 4.0 Hz), 132.71 (d, JcÐp = 9.0 Hz), 204.85 (d, JcÐp = 5.1 Hz).
1
using a KMnO4 basic solution and H NMR spectral data. The
methanol was evaporated in vacuo and to the mixture was added
benzene (30 mL). The benzene (about 20 mL) was evaporated in
vacuo, the solid was removed by filtration. The crude product was
chromatographed on a silica gel column with Et2O/acetone (4:1) as
eluent to give 4a 0.82 g (70% yield).
1H NMR (CDCl3): δ = 1.34 (6H, dt, J = 1.0, 7.2 Hz, 2CH3), 1.38
(6H, s, 2CH3), 4.14 (4H, dq, J = 8.0, 7.2 Hz, 2CH2OP), 4.76 (2H,
dd, J = 3.0, 2.0 Hz, OCH2), 6.60 (1H, dt, J = 12.2, 2.0 Hz, HC=).
31P NMR (CDCl3): δ = 16.48.
IR (film): ν = 1249 (P=O), 1948 (C=C=C), 3620 (OH).
13C NMR(CDCl3): δ = 16.00 (d, JcÐp= 6.14 Hz), 26.37 s, 61.85 (d,
JcÐ p= 5.59 Hz), 73.80(d, JcÐp = 20.28 Hz), 88.75 (d, JcÐp = 19.27 Hz),
127.58 (d, JcÐp = 196.25 Hz), 149.58 (d, JcÐp = 9.96 Hz).
MS: m/z (%) = 246(M+,10), 216(100), 204(23), 188(40), 160(90),
148(22), 120(10), 78(30), 65(20).
Calcd for C11H19PO4: C; 53.66%, H; 7.72%, P; 12.60%. Found: C;
53.96%, H; 7.91%, P; 12.34%.
31P NMR (CDCl3): δ = 12.93.
IR (film): ν = 1250 (P=O), 1609 (C=C).
MS: m/z (%) = 233(M+Ð1,80), 219(38), 204(26), 191(22), 177(50),
163(43), 109(90), 81(100), 65(60).
2-(Diethylphosphono)-4-(2-norbornylidene)buta-2,3-dien-1-ol
(3e)
yield 72%.
Calcd for C10H19PO4: C; 51.28%, H; 8.12%, P; 13.25%. Found: C;
51.54%, H; 8.43%, P; 13.07%.
1H NMR (CDCl3): δ = 1.78 Ð 2,12 (10H, m, CH2, CH), 1.36 (6H, dt,
J = 1.6, 8.0 Hz), 3.7 (1H, br s, OH), 4.10 (4H, dq, J = 7.8, 8.0 Hz,
CH2OP), 4.32 (2H, d, J = 12.4 Hz, CH2OH).
13C NMR[CD3C(O)CD3]: δ = 16.08 (d, JcÐp = 6.1 Hz), 23.18 s,
28.09 s, 35.67 s, 37.42 s, 45.56 s, 46.59 s, 61.53 (d, JcÐp = 12.2 Hz),
61.8 (d, JcÐp = 5.5 Hz), (d, JcÐp = 185.2 Hz), 99.4 (d, JcÐp = 6.5 Hz),
210.3 (d, JcÐp = 210,3 Hz).
2-Chloromethyl-4-(diethylphosphono)-2-methyl-2,5-dihydro-
furan (4b)
yield 75%.
1H NMR (CDCl3): δ = 1.32 (6H, dt, J = 1.0, 7.2 Hz, 2CH3), 1.4 (3H,
s, CH3), 3.51 (2H, s, ClCH2), 4.06 (4H, dq, J = 8.0, 7.2 Hz,
2CH2OP), 4.69 (2H, dd, J = 2.8, 2.1 Hz, OCH2), 6.48 (1H, dt, J =
12.0, 2.1 Hz, HC=).
13C NMR(CDCl3): δ = 16.28 (d, JcÐp = 6.00 Hz), 25.67 s, 51.37 s,
62.01 (d, JcÐp = 5.4 Hz), 73.76 (d, JcÐp = 20.1 Hz), 89.76 (d, JcÐp
19.5 Hz), 127.03 (d, JcÐp = 195.3 Hz), 148.01 (d, JcÐp = 10.2 Hz).
31P NMR (CDCl3): δ = 18.81.
IR (film): ν = 1251 (P=O), 1945 (C=C=C), 3610 (OH).
MS: m/z (%) = 286(M+,10), 256(100), 228(28), 200(40), 81(75),
65(50).
=
Calcd for C14H23PO4: C; 58.74%, H; 8.04%, P; 10.84%. Found: C;
58.98%, H; 8.30%, P; 10.52%.
31P NMR (CDCl3): δ = 12.1.
IR (film): ν = 1249 (P=O), 1611 (C=C).
MS: m/z (%) = 267(M+Ð1,10), 219(85), 204(5), 191(21), 163(72),
109(48), 81(100), 65(48).
2-(Diethylphosphono)-4-(2-cyclohexenylidene)buta-2,3-dien-1-ol
(3f)
yield 63%.
1H NMR (CDCl3): δ = 1.35 (6H, dt, J = 1.6, 8.0 Hz, 2CH3), 1.78
(2H, m, CH2), 2.15 (2H, m, CH2), 2.46 (2H m, CH2), 3.60 (1H, br s,
OH), 4.09 (4H, dq, J = 7.6, 8.0 Hz, 2CH2OP), 4.26 (2H, d, J = 12.4
Hz, CH2OH) 5.88 (1H, m, =CH), 6.01 (1H, m, =CH).
Calcd for C10H18ClPO4: C; 44.69%, H; 6.70%, Cl; 13.22%, P;
11.55%. Found: C; 44.52%, H; 6.53%, Cl; 13.17%, P; 11.52%.
4-(Diethylphosphono)-2-(hydroxymethyl)-2-methyl-2,5-dihy-
drofuran (4c)
yield 73%.
1H NMR (CDCl3): δ = 1.36 (3H, s, CH3), 1.38 (6H, dt, J = 1.0,
7.8 Hz, 2CH3), 3.62 (2H, s, CH2OH), 4.14 (4H, dq, J = 8.0, 7.8 Hz,
CH2OP), 4.3 (1H, br s, OH), 4.8 (2H, dd, J = 2.8, 2.0 Hz, OCH2),
6.58 (1H, dt, J = 12.0, 2.0 Hz, HC=).
13C NMR[CD3C(O)CD3]: δ = 16.36 (d, JcÐp = 6.2 Hz), 21.71 s, 24.79
s, 26.51 (d, JcÐp = 6.2 Hz), 61.69 (d, JcÐp = 11.9 Hz), 62.92 (d, JcÐp
=
6.2 Hz), 93.47 (d, JcÐp = 184.6 Hz), 103.65 (d, JcÐp = 15.1 Hz), (d,
JcÐp = 9.0 Hz), 131.49 (d, JcÐp = 11.2 Hz), 205.08 (d, JcÐp = 5.0 Hz).
31P NMR (CDCl3): δ = 17.00.
13C NMR(CDCl3): δ = 16.28 (d, JcÐp = 5.6 Hz), 20.03 s, 62.19 (d,
JcÐp = 5.4 Hz), 64.01 s, 74.22 (d, JcÐp = 20.2 Hz), 89.71 (d, JcÐp = 18.0
Hz), 128.07 (d, JcÐp = 195.87 Hz), 148.32 (d, JcÐp = 10.0 Hz).
IR (film): ν = 1249 (P=O), 1960 (C=C=C), 3619 (OH).
MS: m/z (%) 272(M+,8), 242(100), 214(34), 186(69), 167(10),
149(5), 127(8), 81(12), 65(8).
31P NMR (CDCl3): δ = 12.65.
Calcd for C13H21PO4: C; 57.35%, H; 7.72%, P; 11.40%. Found: C;
57.55%, H; 7.90%, P; 11.14%.
IR (film): ν = 1251 (P=O), 1608 (C=C); 3631 (OH).
MS: m/z (%) = 249(M+Ð1,25), 235(40), 220(25), 207(10), 81(100),
65(58).
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466
V. K. Brel
PAPER
Calcd for C10H19PO5: C; 48.00%, H; 7.60%, P; 12.40%. Found: C;
48.42%, H; 7.92%, P; 12.08.
31P NMR (CDCl3): δ = 13.21.
IR (film): ν = 1251 (P=O), 1540, 1604 (C=C).
MS: m/z (%) = 271(M+Ð1,100), 243(80), 215(95), 133(60), 107(90),
81(70), 65(40).
4-(Diethylphosphono)-2-ethenyl-2-methyl-2,5-dihydrofuran (4d)
yield 74%.
Calcd for C13H21PO4: C; 57.35%, H; 7.72%, P; 11.40%. Found: C;
57.71%, H; 8.02%, P; 11.00%.
1H NMR (CDCl3): δ = 1.34 (6H, dt, J = 0.8, 7.0 Hz, 2CH3), 1.42
(3H, s, CH3), 4.12 (4H, dq, J = 8.0, 7.0 Hz, 2CH2OP), 4.79 (2H, m,
OCH2), 5.82, 5.25 (2H, ddd, J = 11.0, 17.0 Hz, H2C=), 5.9 (1H, m,
HC=CH2), 6.51 (1H, dt, J = 11.6, 2.5 Hz, HC=CP).
13C NMR(CDCl3): δ = 16.37 (d, JcÐp = 5.4 Hz), 25.02 s, 62.23 (d,
JcÐp = 5.4 Hz), 74.67 (d, JcÐp = 20.9 Hz), 91.06 (d, JcÐp = 19.5 Hz),
References
(1) (a) Claesson, A.; Olsson, L.-I. In The Chemistry of Allenes:
Landor, S.R. Ed.; Academic: London, 1982, vol.3, 737.
(b) Fuks, R.; Viehe, H. G. In The Chemistry of Acetylenes:
Viehe, H.G. Ed.; Marcel Dekker: New York, 1969, 425.
(c) Zefirov, N.S.; Koz'min, A. S.; Kasumov, T. M.; Potekhin,
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113.64 s, 128.67 (d, JcÐp = 195.4 Hz), 139.92 s, 147.39 (d, JcÐp
=
10.9 Hz).
31P NMR (CDCl3): δ = 12.48.
IR (film): ν = 1248 (P=O), 1561, 1610 (C=C).
MS: m/z (%) = 245(M+Ð1,21), 231(30), 218(34), 189(33), 175(36),
162(41), 109(80), 81(100), 65(32).
Calcd for C11H19PO4: C; 53.66%, H; 7.72%, P; 12.60%. Found: C;
53.56%, H; 7.68%, P; 12.50%
4-(Diethylphosphono)-2-(2-norbornylidene)-2,5-dihydrofuran
Mantione, R.; Leroux, Y.; Normant, H. C. R. Acad. Sci. Ser.
(4e)
C. 1970, 270, 1808.
yield 75%.
(4) Gelin, R.; Gelin, S.; Bertrand, M. Bull. Soc. Chim. Fr. 1972,
720.
Toda, F.; Komoda, T.; Akaji, K. Bull. Chem. Soc. Jpn. 1968,
41, 1493.
(5) Hoff, S.; Brandsma, L. Recl. Trav. Chim. Pays-Bas. 1969, 88,
84.
(6) Gelin, R.; Albrand, M.; Gelin, S. C. R. Acad. Sci. Ser. C. 1969,
269, 241.
(7) Claesson, A.; Olsson, L.-I. In The Chemistry of Allenes: Lan-
dor, S.R. Ed.; Academic: London, 1982, vol.2, 369.
(8) Nikam, S. S.; Chu, K.-H.; Wang, K. K. J. Org. Chem. 1986,
51, 745.
1H NMR (CDCl3): δ = 1.18 Ð 1.8, 2.3 (10H, m, CH2, CH), 1.34 (6H,
dt, J = 0.9, 8.0 Hz, 2CH3), 4.16 (4H, dq, J = 8.0, 8.0 Hz, 2CH2OP),
6.72 (1H, dt, J = 12.0, 2.25 Hz, HC=CP).
13C NMR(CDCl3): δ = 16.08 (d, JcÐp = 6.14 Hz), 23.20 s, 28.09 s,
35.69 s, 37.53 s, 45.58 s, 46.69 s, 61.82 (d, JcÐp = 5.48 Hz), 73.52 (d,
JcÐp = 20.08 Hz), 97.73 (d, JcÐp = 19.42 Hz), 129.31 (d, JcÐp = 196.65
Hz), 147.15 (d, JcÐp = 10.77 Hz).
31P NMR (CDCl3): δ = 13.12.
IR (film): ν = 1254 (P=O), 1598 (C=C).
MS: m/z (%) = 285(M+Ð1,100), 257(50), 229(55), 135(40), 107(55),
81(60), 67(40).
(9) Carlson, R.M.; Jones, R.W; Hacher, A.S. Tetrahedron Lett.
1975, 1741.
Calcd for C14H23PO4: C; 58.74%, H; 8.04%, P; 10.84%. Found: C;
58.71%, H; 8.01%, P; 10.84%.
(10) Olsson, L.-I.; Claesson, A. Synthesis 1979, 9, 743.
(11) Brel, V. K. Synthesis 1998, 710.
(12) (a) Alabugin, I.V.; Brel, V.K. Usp. Khim. 1997, 66, 225; Russ.
Chem. Rev., Engl. Trans. 1997, 66, 205; Chem. Abstr. 1998,
128, 114977r.
4-(Diethylphosphono)-2-(2-cyclohexenylidene)-2,5-dihydro-
furan (4f)
yield 73%.
(b) Brel, V. K.; Abramkin, E. V.; Chekhlov, A. N.; Martynov,
I. V. Dokl. Akad. Nauk SSSR. 1990, 312, 619; Chem. Abstr.
1991, 114, 122513n.
1H NMR (CDCl3): δ = 1.32 (2H, m, CH2), 1.36 (6H, dt, J = 0.9,
8.0 Hz, 2CH3), 1.77 (2H, m, CH2), 2.04 (2H, m, CH2) 4.11 (4H, dq,
J = 8.0, 8.0 Hz, 2CH2OP), 4.74 (2H, m, OCH2), 5.56 (1H, br d, J =
10.0 Hz, HC=CH), 5.91 (1H, dt, J = 10.0, 4.0 Hz, HC=CH), 6.51
(1H, dt, J = 12.0, 2.0 Hz, HC=CP).
13C NMR(CDCl3): δ = 16.33 (d, JcÐp = 6.7 Hz), 19.70 s, 24.65 s,
33.72 s, 62.19 (d, JcÐp = 5.5 Hz), 74.10 (d, JcÐp = 20.8 Hz), 88.53 (d,
JcÐp=17.8 Hz), 127.81 s, 129.11 (d, JcÐp = 194.5 Hz), 131.44 s,
148.00 (d, JcÐp = 10.8 Hz).
(13) Wolfgang, R. In The Chemistry of Allenes: Landor, S.R. Ed.;
Academic: London, 1982, vol.2, 832Ð847.
(14) Brandsma, L. Preparative Acetylenic Chemistry, Elsevier:
Amsterdam, 1988, 265.
Synthesis 1999, No. 3, 463–466 ISSN 0039-7881 © Thieme Stuttgart · New York