Synthesis and intramolecular cyclization of diethylphosphono-substituted allenic glycols

Article abstract of DOI:10.1055/s-2001-16078

This paper describes a convenient and efficient synthesis of new (2R)-5-substituted-5-(diethylphosphono)-penta-3,4-dien-1,2-diols. Phosphorylated allenic glycols are stable enough compounds, but under basic conditions they cyclized to (3R)-5-(3-hydroxy-2,3-dihydrofuryl) (diethylphosphono)alkanes through intramolecular nucleophilic addition of the terminal alkoxide to the central carbon atom of the allene system. Treatment of (3R)-5-(3hydroxy-2,3-dihydrofuryl)(diethylphosphono)alkanes with a catalytic amount of p-toluenesulfonic acid in chloroform at 40-45 °C for 0.5 hours afforded diethylphosphono(2-furyl)alkanes.

Full text of DOI:10.1055/s-2001-16078

PAPER
1539
Synthesis and Intramolecular Cyclization of Diethylphosphono-Substituted
Allenic Glycols
Synthesis and Intramolecular
l
Cycliza
e
tion of
D
ie
r
thylphos
y
phono-Substituted
K
Allenic
G
lycols . Brel*
Institute of Physiologically Active Compounds, Russian Academy of Science, Chernogolovka, Moscow Region, 142432, Russia
Fax +7(095)9132113; E-mail: brel@ipac.ac.ru
Received 12 February 2001; revised 24 April 2001
ylphosphono)alkanes
2
from (2R)-5-substituted-5-
Abstract: This paper describes a convenient and efficient synthesis
of new (2R)-5-substituted-5-(diethylphosphono)-penta-3,4-dien-
1,2-diols. Phosphorylated allenic glycols are stable enough com-
pounds, but under basic conditions they cyclized to (3R)-5-(3-hy-
(diethylphosphono)penta-3,4-dien-1,2-diols 8 and dieth-
ylphosphono(2-furyl)alkanes 3 using phosphorus contain-
ing allenes 8 as intermediates.
droxy-2,3-dihydrofuryl)(diethylphosphono)alkanes
through
The diethylphosphono-2,3-dihydrofurans 2 were synthe-
sized by a simple and efficient three-step procedure via
propargylic alcohols 5a–i and phosphorylated diols 8a–i
(Scheme 2). The starting material, 2,3-O-isopropylidene-
D-glyceraldehyde 4, was prepared from D-mannitol. D-
mannitol has been ketalized using a variety of methods9 to
provide 1,2:5,6-diisopropylidene-D-mannitol. We select-
ed the procedure reported by Chittenden,10 which uses cat-
intramolecular nucleophilic addition of the terminal alkoxide to the
central carbon atom of the allene system. Treatment of (3R)-5-(3-
hydroxy-2,3-dihydrofuryl)(diethylphosphono)alkanes with a cata-
lytic amount of p-toluenesulfonic acid in chloroform at 40–45 °C
for 0.5 hours afforded diethylphosphono(2-furyl)alkanes.
Key words: cyclization, furans, 2,3-dihydrofurans, phosphaal-
lenes, phosphorus heterocycles
alytic
stannous
chloride
(SnCl2)
and
2,2-
dimethoxypropane and obtained the ketal in ~60% yield.
The 1,2:5,6-diisopropylidene-D-mannitol was converted
to D-glyceraldehyde 4 with a silica gel-supported sodium
metaperiodate reagent in powder form.11 The propargyl
alcohols were prepared in ~80% yield by a standard pro-
cedure, starting from acetylenes and D-glyceraldehyde
4.12
Allenes and their derivatives have received considerable
attention as useful building blocks and intermediates in
organic synthesis.1,2 The introduction of different func-
tional groups makes it possible to expand the range of pos-
sible synthetic reactions of allenes. Synthesis of allenic
alcohols can be of interest with this in view. In the litera-
ture, several examples of cyclizations of allenic alcohols
to 2,5-dihydrofurans3 or furans4 have been described. Ap-
plication of this approach to phosphorus-containing al-
lenes can open the way to phosphorylated furans and
dihydrofurans. However, relatively little work has been
performed on the synthesis and study of intramolecular
cyclization of phosphorylated allenic carbinols.5,6 Recent-
ly, we have described an easy synthesis of 4-(dieth-
ylphosphono)-2,5-dihydrofurans 1 from of diethyl-
phosphono-substituted -allenic carbilnols (Scheme 1).6
O
O
O
O
(R)
a
(R)
b
R
80%
CHO
95%
OH
4
5a-i
O
O
(R)
O
O
R
d
(R)
c
R
.
92%
85%
(EtO)2(O)P
R
H
OP(OEt)2
R
R
O
O
O
6a-i
7a-i
(EtO)2(O)P
(EtO)2(O)P
Me
(R)
(EtO)2(O)P
R
OH
HO
(R)
OH
1
2
3
O
R
e
(EtO)2(O)P
.
Scheme 1
52-83%
(R)
(EtO)2(O)P
H
OH
8a-i
2a-f
In continuation of our earlier work on the synthesis of 1,2-
and 1,3-alkadienes,7 and in connection with our interest in
developing new synthetic strategies for the construction
of phosphonic heterocycles,6,8 we herein present the syn-
thesis of (3R)-5-(3-hydroxy-2,3-dihydrofuryl)(dieth-
CR≡CMgBr; (b) ClP(OEt)2, Et3N, Et2O, -40 oC; (c) r.t., 24 h;
(d) MeOH, H+, 50 oC, 1h; (e) Et3N, 45 oC, 48 h.
(a)
R = H (a); C6H5 (b); p-CH3C6H4 (c); HOCH2 (d); CH3OCH2 (e);
CH(OH)CH3 (f); n-C4H9 (g); n-C5H11 (h); n-C6H13 (i).
Scheme 2
Synthesis 2001, No. 10, 30 07 2001. Article Identifier:
1437-210X,E;2001,0,10,1539,1545,ftx,en;E01901SS.pdf.
© Georg Thieme Verlag Stuttgart · New York
ISSN 0039-7881

1540
V. K. Brel
PAPER
Phosphorylated allenes 8 were synthesized directly from Compounds 2a–f and 3a–f were identified by IR, 1H, 13
C
propargylic alcohols 5a–i in ~70% yield by Horner–Mark and 31P NMR spectral data. For example, the IR spectra of
[2,3]-sigmatropic rearrangement13 of the unstable phos- compounds 3a–f displayed absorption bands of the phos-
phites 6 generated in situ by reaction with diethyl chloro- phoryl group at 1249–1259 cm–1, double bonds at ~1570,
phosphite in the presence of triethylamine in diethyl ether. 1600 cm–1, and hydroxyl group at 3350–3660 cm–1 (for
1
31P NMR spectroscopy was used to monitor the reaction. 3d, 3f). The H NMR spectrum of the 2,3-dihydrofurans
The deprotection of the isopropylidene group proceeded 2a–f showed signals of the protons for ethoxy groups, and
in high yield upon treating phosponates 7 with 1 M HCl in the signals at 4.9 and 5.3 ppm related to the protons at C-
methanol at 50–60 °C. Compounds 8a–i were stable 3 and C-4, respectively. The chemical shifts of the corre-
enough to be handled at ambient temperature. Analytical- sponding tertiary and quaternary ethylenic carbon, respec-
ly pure allenes 8a–i were isolated as colorless or pale yel- tively at 101–102 and 154–157 ppm, confirms the
low oils by column chromatography on silica gel.
presence of the enol ether15 in 2a–f. The chemical shift
= 23–25 ppm for 2a–f and 3a–f is characteristic for
P
The glycols 8a–i were obtained as mixtures of two diaste-
reomers (31P NMR spectral data, in 1:1–1.4 ratio) result-
ing from chirality of the allenic group. The chemical shift
compounds with a 4-coordinate phosphorus atom linked
with an sp3-hybridized carbon atom.
of phosphorus is characteristic for compounds with a 4- In summary, we have described an easy and convenient
coordinate phosphorus atom linked with an sp2-hybrid- method for the preparation of synthetically valuable (3R)-
ized carbon atom. The extremely low-field position of the 5-(3-hydroxy-2,3-dihydrofuryl)(diethylphosphono)al-
allenic central carbon atom resonance (near 210 ppm rel- kanes from (2R)-5-substituted-5-(diethylphosphono)-
ative to tetramethylsilane) allows for the immediate iden- penta-3,4-dien-1,2-diols as starting materials. Treatment
tification of the allenic moiety by 13C NMR of (3R)-5-(3-hydroxy-2,3-dihydrofuryl)(diethylphospho-
spectroscopy.14 The chemical shift for signals of the allen- no)alkanes with a catalytic amount of p-toluenesulfonic
ic central carbon atom of phosphorylated allene 8 is
211–212 ppm.
=
acid in chloroform afforded diethylphosphono(2-furyl)al-
kanes. Future studies on this potentially important syn-
thetic methodology are currently in progress.
Applications of phosphorylated allenes to the synthesis of
interesting phosphonic heterocycles will be reported in
due course.
The phosphorylated allenic glycols are stable compounds,
but under basic conditions they cyclize to 2,3-dihydro-
furans by nucleophilic addition of the terminal alkoxide to
the central carbon atom of the allene system. Reactions
were performed in the presence of triethylamine in anhy-
drous chloroform at 45–50 °C for 48 hours. Cyclizations
of 8a–f were monitored by TLC and 1H NMR spectral da-
ta. Inspection of the 1H NMR spectrum of the crude mate-
rial showed a high conversion of 8a–f to dihydrofurans
2a–f. When the substituents R were sterically bulky (R =
n-C4H9, n-C5H11, n-C6H13), attempts to cyclize glycols
8g–i with triethylamine were unsuccessful, affording only
NMR spectra were recorded on a Bruker CXP-200 spectrometer at
200 MHz (1H), 81.01 MHz (31P) and 50.3 MHz (13C). Chemical
shifts for 1H and 13C NMR are reported in ppm relative to TMS as
internal standard. 31P downfield shifts ( ) are expressed with a pos-
itive sign, relative to external 85% H3PO4 in H2O. IR spectra (films)
were recorded on a Bruker IFS-113 spectrometer. Column chroma-
tography was performed with Fluka Silica gel 60 (0.035–0.070
mm). Preparative TLC was performed on Fluka Silica gel/TLC-
trace amounts of 2,3-dihydrofurans (1H NMR analysis). cards (20 20 0.2 cm). All reagents were of commercial quality
or were purified before use. Organic solvents were purified and
All of the 2,3-dihydrofurans were isolated as colorless oils
dried by standard procedures.16 Propargyl alcohol was protected by
by column chromatography on alumina.
reaction with ethyl vinyl ether to afford the ether in nearly quantita-
tive yield by standard procedures.12 The details of the preparation of
O-protected propargyl alcohol have been described earlier.7a
The 2,3-dihydrofurans 2a–f can lead to -substituted
furans, a system that occurs in a number of natural prod-
ucts.4b Reaction of 2a–f with a catalytic amount of p-tolu-
enesulfonic acid at 40–45 °C for 2 hours led to
diethylphosphonofurans 3a–f (monitored by TLC on sili-
ca gel), which were isolated as stable colorless oils by col-
umn chromatography on silica gel (Scheme 3).
(2R)-5-(Diethylphosphono)penta-3,4-dien-1,2-diol (8a)
Purified anhyd THF (100 mL) was placed in a 50-mL flask, acety-
lene was introduced through a gas-inlet tube at the rate of 2–3 L/h,
and the stirrer was started. After 30 min, ethynylmagnesium bro-
mide [prepared from magnesium turnings (0.48 g, 0.02 g-atom), and
ethyl bromide (2.4 g, 0.022 mol) in THF (25 mL)] was added over
2 h; the temperature of the reaction increased 5–10 °C, and the mix-
ture was stirred at 30–35 °C for 1 h. The mixture was cooled in an
ice bath and 2,3-O-isopropylidene-D-glyceraldehyde, (3.12 g, 0.024
mol) in THF (15 mL) was added over 15 min. The mixture was then
stirred and heated to 40–45 °C for a further 2 h. The mixture was
cooled and sat. NH4Cl was added carefully to dissolve the solid
components. The two layers were separated and the aqueous phase
was extracted with Et2O (3 15 mL). The combined organic frac-
tions were dried (K2CO3) and the solvent was evaporated in vacuo.
To a solution of crude acetylenic alcohol 5a (2.3 g, 0.0148 mol) in
Et2O (50 mL) under N2 was added Et3N (1.62 g, 0.016 mol) and the
mixture was cooled to –50 °C. A solution of diethyl chlorophosphite
R
R
O
-H2O
O
(EtO)2(O)P
(EtO)2(O)P
68-90%
(R)
OH
2a-f
3a-f
R = H (a); C6H5 (b); p-CH3C6H4 (c); HOCH2 (d); CH3OCH2 (e);
CH(OH)CH3 (f).
Scheme 3
Synthesis 2001, No. 10, 1539–1545 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Synthesis and Intramolecular Cyclization of Diethylphosphono-Substituted Allenic Glycols
1541
(2.18 g, 0.014 mol) in Et2O (10 mL) was added dropwise and the
mixture was then stirred at –50 °C over 1 h, and at r.t. for 24 h. The
solid was removed by filtration and the solvent was evaporated in
vacuo. The crude phosphorylated allene 7a was dissolved in MeOH
(20 mL) and 35% HCl (1–2 drops) was added. The solution was
stirred at 50–60 °C for 2 h and the solvent was evaporated in vacuo.
The crude product was isolated by column chromatography on sili-
ca gel (CHCl3–MeOH, 10:1.2) to yield 8a (2.4 g, 52%) as an oil.
TLC (diastereomeric mixture): Rf = 0.53, 0.56 (CHCl3–MeOH,
10:1.3).
=CH), 98.63 (d, JC-P = 186.3 Hz, =CH-P), 98.63 (d, JC-P = 187.1 Hz,
=CH-P), 127.30 (d, JC-P = 6.0 Hz, Ph), 127.35 (d, JC-P = 6.0 Hz, Ph),
127.68 (s, Ph), 128.14 (s, Ph), 128.44 (s, Ph), 209.89 (d, JC-P = 4.4
Hz, =C=), 210.63 (d, JC-P = 5.0 Hz, =C=).
31P NMR (CDCl3) (diastereomeric mixture): = 16.87, 16.56.
Anal. Calcd for C15H21PO5 (312.30): C, 57.69; H, 6.77; P, 9.92.
Found: C, 57.56; H, 6.70; P, 9.82.
(2R)-5-Tolyl-5-(diethylphosphono)penta-3,4-dien-1,2-diol (8c)
Prepared from propargylic alcohol 5c (3.69 g, 0.015 mol), anhyd
Et2O (75 mL), Et3N (1.717 g, 0.017 mol), and diethyl chlorophos-
phite (2.34 g, 0.015 mol). Workup and chromatography (CHCl3–
MeOH, 10:1.2) afforded 3.6 g (74%) of 8c. TLC (diastereomeric
mixture): Rf = 0.46, 0.45 (CHCl3–MeOH, 10:1.0).
IR (film): = 1246, 1593, 1615, 1953, 3369, 3683 cm–1.
1H NMR (CHCl3): = 1.31 (dt, 6 H, JH-H = 7.2 Hz, JH-P = 1.8 Hz, 2
IR (film): = 1230, 1959, 3360, 3667 cm–1.
1H NMR (CDCl3): = 1.32 (dt, 6 H, JH-H = 7.2 Hz, JH-P = 1.6 Hz, 2
CH3), 3.67 (m, 2 H, CH2OH), 3.80 (br s, 2 H, 2 OH), 4.08 (dq, 4 H,
JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2 CH2OP), 4.40 (br s, 1 H, CHOH),
5.44 (m, 1 H, HC=), 5.62 (ddd, 1 H, JH-H = 6.5 Hz, JH-H = 6.6 Hz,
JH-P = 13.1 Hz, HC=).
13C NMR (CDCl3) (diastereomeric mixture): = 16.20 (d, JC-P = 6.5
Hz, 2 CH3), 62.68 (d, JC-P = 6.8 Hz, 2 CH2OP), 62.68 (d, JC-P = 6.9
Hz, 2 CH2OP), 65.79 (d, JC-P = 4.0 Hz, CH2OH), 69.95 (d, JC-P = 4.1
Hz, CH2OH), 69.14 (d, JC-P = 6.3 Hz, CH2OH), 69.22 (d, JC-P = 6.4
CH3), 2.39 (s, 3 H, CH3), 3.62 (m, 2 H, CH2OH), 4.18 (dq, 4 H,
JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2 CH2OP), 4.22 (br s, 2 H, 2 OH), 5.27
(br s, 1 H, CHOH), 5.86 (dd, 1 H, JH-H = 5.6 Hz, JH-P = 11.9 Hz,
HC=), 7.28 (d, 2 H, Tol), 7.41 (d, 2 H, Tol).
Hz, CH2OH), 81.57 (d, JC-P = 193.7 Hz, =CH-P), 81.62 (d, JC-P
193.6 Hz, =CH-P), 94.07 (d, JC-P = 16.0 Hz, =CH), 94.42 (d, JC-P
15.8 Hz, =CH), 211.13 (s, =C=), 211.94 (s, =C=).
=
=
13C NMR (CDCl3) (diastereomeric mixture): = 16.13 (d, JC-P = 6.6
Hz, 2 CH3), 21.24 (s, CH3), 62.53 (d, JC-P = 5.7 Hz, 2 CH2OP), 62.32
(d, JC-P = 6.1 Hz, 2 CH2OP), 65.55 (d, JC-P = 3.4 Hz, CH2OH), 66.05
(d, JC-P = 4.2 Hz, CH2OH), 69.49 (d, JC-P = 6.0 Hz, CHOH), 69.85
(d, JC-P = 6.0 Hz, CHOH), 98.17 (d, JC-P = 15.3 Hz, =CH), 98.85 (d,
JC-P = 15.2 Hz, =CH), 99.87 (d, JC-P = 187.4 Hz, =CH-P), 99.94 (d,
31P NMR (CDCl3) (diastereomeric mixture): = 14.08, 14.12.
Anal. Calcd for C9H17PO5 (236.23): C, 45.76; H, 7.20; P, 13.14.
Found: C, 45.71; H, 7.19; P, 13.09.
JC-P = 188.4 Hz, =CH-P), 127.21 (s, Tol), 127.44 (d, JC-P = 6.0 Hz,
(2R)-5-Phenyl-5-(diethylphosphono)penta-3,4-dien-1,2-diol
(8b); Typical Procedure
Tol), 127.53 (d, JC-P = 6.0 Hz, Tol), 128.17 (s, Tol), 128.52 (s, Tol),
210.52 (d, JC-P = 4.8 Hz, =C=), 210.72 (d, JC-P = 5.1 Hz, =C=).
A solution of ethylmagnesium bromide [prepared from magnesium
turnings (0.48 g, 0.02 g-atom), and ethyl bromide (2.4 g, 0.022 mol)
in anhyd Et2O (100 mL)] was cooled to 0 °C, and ethynylbenzene
(2.14 g, 0.021 mol) was added dropwise. The solution was stirred
for 15 min at 0 °C, warmed to 34–35 °C, stirred for 2 h, and then
cooled to 0 °C. A solution of 2,3-O-isopropylidene-D-glyceralde-
hyde (2.73 g, 0.021 mol) in Et2O (15 mL) was added dropwise. Af-
ter stirring for 2 h at 34–35 °C, the reaction was cooled to 0 °C, and
quenched with sat. NH4Cl. The organic layer was separated and the
aqueous layer was extracted with Et2O (3 20 mL). The combined
organic layers were dried (K2CO3), filtered, and concentrated in
vacuo to afford crude propargyl alcohol 5b. To a solution of crude
alcohol 5b (3.25 g, 0.014 mol) in Et2O (50 mL) under N2 was added
Et3N (1.62 g, 0.016 mol) and the mixture was cooled to –50 °C. A
solution of diethyl chlorophosphite (2.18 g, 0.014 mol) in Et2O (10
mL) was added dropwise and the mixture was then stirred at –50 °C
over 1 h, and at r.t. for 5 h. The solid was removed by filtration and
the solvent was evaporated in vacuo. The crude phosphorylated al-
lene 7b was dissolved in CH3OH (20 mL) and 35% HCl (1–2 drops)
was added. The solution was stirred at 50–60 °C for 2 h and the sol-
vent was evaporated in vacuo. The crude product was isolated by
column chromatography on silica gel (CHCl3–MeOH, 10:1.2) to
yield 8b (3.4 g, 54%) as an oil. TLC (diastereomeric mixture): Rf =
0.45, 0.43 (CHCl3–MeOH, 10:1).
31P NMR (CDCl3) (diastereomeric mixture): = 16.42, 16.73.
Anal. Calcd for C16H23PO5 (326.33): C, 58.89; H, 7.10; P, 9.45.
Found: C, 59.03; H, 7.10; P, 9.53.
(2R)-5-(Diethylphosphono)hexa-3,4-dien-1,2,6-triol (8d)
Prepared from propargylic alcohol 5d (2.84 g, 0.011 mol), anhyd
Et2O (50 mL), Et3N (1.212 g, 0.012 mol), and diethyl chlorophos-
phite (1.716 g, 0.011 mol). Workup and chromatography (CHCl3–
MeOH, 10:1.2) afforded 1.76 g (60%) of 8d. TLC (diastereomeric
mixture): Rf = 0.35, 0.34 (CHCl3–MeOH, 10:1.2).
IR (film): = 1228, 1956, 3343, 3678 cm–1.
1H NMR (CDCl3): = 1.32 (dt, 6 H, JH-H = 7.1 Hz, JH-P = 1.6 Hz, 2
CH3), 3.65 (m, 2 H, CH2OH), 4.10 (dq, 4 H, JH-H = 7.1 Hz, JH-P
=
6.6 Hz, 2 CH2OP), 4.25 (m, 2 H, CH2OH), 4.37 (m, 1 H, JH-P = 10.6
Hz, CHOH), 4.6 (br s, 2 H, 2 OH), 5.70 (dm, 1 H, JH-P = 12.6 Hz,
HC=).
13C NMR (CDCl3) (diastereomeric mixture): = 16.11 (d, JC-P = 6.5
Hz, 2 CH3), 59.16 (d, JC-P = 10.8 Hz, CH2OH), 62.76 (d, JC-P = 7.4
Hz, 2 CH2OP), 62.90 (d, JC-P = 7.6 Hz, 2 CH2OP), 65.45 (d, JC-P
4.4 Hz, CH2OH), 65.69 (d, JC-P = 4.0 Hz, CH2OH), 69.20 (d, JC-P
6.0 Hz, CHOH), 69.28 (d, JC-P = 6.0 Hz, CHOH), 96.81 (d, JC-P
15.5 Hz, =CH), 96.89 (d, JC-P = 15.5 Hz, =CH), 97.74 (d, JC-P
186.0 Hz, =CH-P), 97.76 (d, JC-P = 186.1 Hz, =CH-P), 207.16 (d,
JC-P = 4.9 Hz, =C=), 207.21 (d, JC-P = 5.4 Hz, =C=).
=
=
=
=
IR (film): = 1248, 1584, 1600, 1950, 3365, 3689 cm–1.
1H NMR (CDCl3): = 1.32 (dt, 6 H, JH-H = 7.3 Hz, JH-P = 1.7 Hz, 2
31P NMR (CDCl3) (diastereomeric mixture): = 17.56, 17.59.
CH3), 3.74 (m, 2 H, CH2OH), 4.20 (dq, 4 H, JH-H = 7.3 Hz, JH-P
=
Anal. Calcd for C10H19PO6 (266.23): C, 45.12; H, 7.12; P, 11.63.
Found: C, 45.09; H, 7.19; P, 11.63.
6.8 Hz, 2 CH2OP), 4.42 (br s, 2 H, 2 OH), 5.31 (br s, 1 H, CHOH),
5.88 (dd, 1 H, JH-H = 5.6 Hz, JH-P = 11.9 Hz, HC=), 7.32 (m, 3 H,
Ph), 7.54 (m, 2 H, Ph).
(2R)-5-(Diethylphosphono)-6-methoxyhexa-3,4-dien-1,2-diol
(8e)
Prepared from propargylic alcohol 5e (3.4 g, 0.017 mol), anhyd
Et2O (75 mL), Et3N (1.82 g, 0.018 mol), and diethyl chlorophos-
phite (2.65 g, 0.017 mol). Workup and chromatography (CHCl3–
13C NMR (CDCl3) (diastereomeric mixture): = 16.15 (d, JC-P = 6.5
Hz, 2 CH3), 62.77 (d, JC-P = 5.4 Hz, 2 CH2OP), 62.84 (d, JC-P = 5.9
Hz, 2 CH2OP), 65.90 (d, JC-P = 3.7 Hz, CH2O), 65.95 (d, JC-P = 4.0
Hz, CH2O), 69.54 (d, JC-P = 5.8 Hz, CHOH), 69.59 (d, JC-P = 6.0 Hz,
CHOH), 96.04 (d, JC-P = 15.1 Hz, =CH), 96.41 (d, JC-P = 15.2 Hz,
Synthesis 2001, No. 10, 1539–1545 ISSN 0039-7881 © Thieme Stuttgart · New York

1542
V. K. Brel
PAPER
MeOH, 10:1.2) afforded 2.95 g (62%) of 8e. TLC (diastereomeric
mixture): Rf = 0.39, 038 (CHCl3–MeOH, 10:1.0).
IR (film): = 1227, 1959, 3388, 3668 cm–1.
2 H, 2 OH), 4.08 (dq, 4 H, JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2 CH2OP),
4.32 (br m, 1 H, CH(OH), 5.52 (ddm, 1 H, JH-H = 3.11, JH-P = 13.2
Hz, JH-H = 5.30 Hz, HC=).
13C NMR (CDCl3) (diastereomeric mixture): = 13.74 (s, CH3),
16.22 (d, JC-P = 6.4 Hz, 2 CH3), 22.07 (s, CH2), 27.56 (d, JC-P = 5.3
Hz, CH2), 30.05 (d, JC-P = 6.5 Hz, CH2), 62.47 (d, JC-P = 6.0 Hz, 2
CH2OP), 65.69 (d, JC-P = 3.9 Hz, CH2OH), 66.04 (d, JC-P = 4.7 Hz,
CH2OH), 69.36 (d, JC-P = 6.3 Hz, CHOH), 69.51 (d, JC-P = 6.5 Hz,
CHOH), 95.26 (d, JC-P = 16.2 Hz, =CH), 95.72 (d, JC-P = 16.4 Hz,
=CH), 96.15 (d, JC-P = 184.2 Hz, =CH-P), 96.38 (d, JC-P = 185.0 Hz,
=CH-P), 207.55 (d, JC-P = 6.1 Hz, =C=), 208.67 (d, JC-P = 6.8 Hz,
=C=).
1H NMR (CDCl3): = 1.31 (dt, 6 H, JH-H = 7.2 Hz, JH-P = 1.7 Hz, 2
CH3), 3.35 (s, 3 H, OCH3), 3.65 (m, 2 H, CH2OH), 4.02 (m, 2 H,
CH2OCH3), 4.12 (dq, 4 H, JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2 CH2OP),
4.20 (br s, 2 H, 2 OH), 4.37 (br s, 1 H, CHOH), 5.58 (dm, 1 H, JH-P
= 12.51 Hz, HC=).
13C NMR (CDCl3) (diastereomeric mixture): = 16.20 (d, JC-P = 6.5
Hz, 2 CH3), 58.10 (s, OCH3), 62.76 (d, JC-P = 6.0 Hz, 2 CH2OP),
65.57 (d, JC-P = 4.0 Hz, CH2O), 65.76 (d, JC-P = 4.0 Hz, CH2O),
69.22 (d, JC-P = 6.1 Hz, CH-OH), 69.31 (d, JC-P = 6.0 Hz, CH2O),
93.95 (d, JC-P = 188.0 Hz, =CH-P), 93.96 (d, JC-P = 188.0 Hz, =CH-
P), 95.59 (d, JC-P = 15.9 Hz, =CH), 96.80 (d, JC-P = 15.9, =CH),
208.72 (d, JC-P = 5.1 Hz, =C=), 209.21 (d, JC-P = 5.6 Hz, =C=).
31P NMR (CDCl3) (diastereomeric mixture): = 19.72, 19.77.
Anal. Calcd for C13H25PO5 (292.31): C, 53.42; H, 8.62; P, 10.60.
Found: C, 53.43; H, 8.56; P, 10.65.
31P NMR (CDCl3) (diastereomeric mixture): = 17.44, 16.46.
(2R)-5-(Diethylphosphono)deca-3,4-dien-1,2-diol (8h)
Anal. Calcd for C11H21PO6 (280.25): C, 47.14; H, 7.55; P, 11.05.
Found: C, 47.12; H, 7.43; P, 11.16.
Prepared from propargylic alcohol 5h (4.07 g, 0.018 mol), anhyd
Et2O (75 mL), Et3N (1.97 g, 0.0195 mol), and diethyl chlorophos-
phite (2.80 g, 0.018 mol). Workup and chromatography (CHCl3–
MeOH, 10:1.2) afforded 4.13 g (75%) of 8h. TLC (diastereomeric
mixture): Rf = 0.40, 042 (CHCl3–MeOH, 10:1.0).
(2R)-5-(Diethylphosphono)hepta-3,4-dien-1,2,6-triol (8f)
Prepared from propargylic alcohol 5f (2.00 g, 0.01 mol), anhyd
Et2O (75 mL), Et3N (1.21 g, 0.012 mol), and diethyl chlorophos-
phite (1.56 g, 0.01 mol). Workup and chromatography (CHCl3–
MeOH, 10:1.2) afforded 1.82 g (65%) of 8f. TLC (diastereomeric
mixture): Rf = 0.45, 0.51 (CHCl3–MeOH, 10:1.5).
IR (film): = 1228, 1948, 3388, 3668 cm–1.
1H NMR (CDCl3): = 0.89 (t, 3 H, JH-H = 7.7 Hz, CH3), 1.30 (m 10
H, 2 CH2 + 2 CH3), 1.47 (m, 2 H, CH2), 2.11 (ddt, 2 H, JH-H = 3.12
Hz, JH-P = 10.83 Hz, JH-H = 8.00 Hz, CH2), 3.61 (m, 2 H, CH2OH),
3.94 (br s, 2 H, 2 OH), 4.08 (dq, 4 H, JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2
CH2OP), 4.32 (br m, 1 H, JH-H = 5.3 Hz, JH-P = 11.72 Hz, CH(OH),
5.53 (ddm, 1 H, JH-H = 3.12, JH-P = 13.18 Hz, JH-H = 5.30 Hz, HC=).
13C NMR (CDCl3) (diastereomeric mixture): = 14.01 (s, CH3),
16.29 (d, JC-P = 6.5 Hz, 2 CH3), 22.36 (s, CH2), 27.68 (d, JC-P = 6.6
Hz, CH2), 27.70 (d, JC-P = 6.5 Hz, CH2), 27.88 (d, JC-P = 5.2 Hz,
CH2), 27.92 (d, JC-P = 5.3 Hz, CH2), 31.20 (s, CH2), 31.23 (s, CH2),
62.52 (d, JC-P = 6.0 Hz, CH2O), 65.78 (d, JC-P = 4.0 Hz, CH2O),
66.13 (d, JC-P = 4.4 Hz, CH2O), 69.48 (d, JC-P = 6.3 Hz, CHOH),
69.57 (d, JC-P = 6.4 Hz, CHOH), 95.29 (d, JC-P = 16.4 Hz, =CH),
95.76 (d, JC-P = 16.4 Hz, =CH), 96.27 (d, JC-P = 184.2 Hz, =CH-P),
96.46 (d, JC-P = 184.6 Hz, =CH-P), 207.60 (d, JC-P = 5.9 Hz, =C=0),
208.67 (d, JC-P = 6.8 Hz, =C=).
IR (film): = 1231, 1954, 3386, 3680 cm–1.
1H NMR (CDCl3): = 1.30 (dt, 6 H, JH-H = 7.2 Hz, JH-P = 1.9 Hz, 2
CH3), 1.33 (d, 3 H, JH-P = 7.8 Hz, CH3), 3.68 (m, 2 H, CH2OH), 4.15
(dq, 4 H, JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2 CH2OP), 4.35 (br m, 1 H,
CH(OH)CH3, 4.44 (m, 1 H, CHOH), 4.81 (br s, 2 H, 2 OH), 5.68
(dm, 1 H, JH-P = 12.4 Hz, HC=).
13C NMR (CDCl3) (diastereomeric mixture): = 16.11 (d, JC-P = 6.5
Hz, 2 CH3), 16.13 (d, JC-P = 6.4 Hz, 2 CH3), 22.71 (d, JC-P = 4.2 Hz,
CH3), 22.79 (d, JC-P = 4.4 Hz, CH3), 22.84 (d, JC-P = 4.0 Hz, CH3),
22.88 (d, JC-P = 4.2 Hz, CH3), 62.85 (d, JC-P = 6.0 Hz, 2 CH2OP),
62.88 (d, JC-P = 5.9 Hz, 2 CH2OP), 62.95 (d, JC-P = 6.1 Hz, 2
CH2OP), 63.03 (d, JC-P = 6.0 Hz, 2 CH2OP), 64.68 (s, CH), 64.77 (s,
CH), 64.89 (s, CH), 65.00 (s, CH), 65.61 (d, JC-P = 6.3 Hz, CH),
65.68 (d, JC-P = 6.0 Hz, CH), 65.85 (d, JC-P = 6.1 Hz, CH), 65.91 (d,
JC-P = 6.2 Hz, CH), 69.32 (d, JC-P = 6.2 Hz, CH2OH), 69.44 (d, JC-P
= 6.0 Hz, CH2OH), 69.49 (d, JC-P = 6.1 Hz, CH2OH), 69.54 (d, JC-P
= 6.0 Hz, CH2OH), 96.81 (d, JC-P = 15.0 Hz, =CH), 96.88 (d, JC-P
15.0 Hz, =CH), 97.56 (d, JC-P = 15.5. Hz, =CH), 97.75 (d, JC-P = 15.4
Hz, =CH), 101.62 (d, JC-P = 184.2 Hz, =CHP), 101.67 (d, JC-P
184.5 Hz, =CHP), 102.53 (d, JC-P = 185.5 Hz, =CHP), 102.67 (d, JC-
P = 185.3 Hz, =CHP), 206.53 (d, JC-P = 5.2 Hz, =C=), 206.61 (d, JC-
P = 5.5 Hz, =C=), 206.75 (d, JC-P = 5.2 Hz, =C=), 206.81 (d, JC-P
5.2 Hz, =C=).
31P NMR (CDCl3) (diastereomeric mixture): = 17.83, 17.98,
18.02, 18.07.
31P NMR (CDCl3) (diastereomeric mixture): = 20.45, 20.49.
Anal. Calcd for C14H27PO5 (306.33): C, 54.89; H, 8.88; P, 10.11.
Found: C, 54.78; H, 8.99; P, 9.97.
=
=
(2R)-5-(Diethylphosphono)undeca-3,4-dien-1,2-diol (8i)
Prepared from propargylic alcohol 5i (3.84 g, 0.016 mol), anhyd
Et2O (75 mL), Et3N (1.77 g, 0.0175 mol), and diethyl chlorophos-
phite (2.50 g, 0.016 mol). Workup and chromatography (CHCl3–
MeOH, 10:1.2) afforded 3.58 g (70%) of 8i. TLC (diastereomeric
mixture): Rf = 0.46, 0.47 (CHCl3–MeOH, 10:1).
=
IR (film): = 1226, 1951, 3348, 3688 cm–1.
Anal. Calcd for C11H21PO6 (280.25): C, 47.14; H, 7.55; P, 11.05.
Found: C, 47.20; H, 7.57; P, 10.96.
1H NMR (CDCl3): = 0.91 (t, 3 H, JH-H = 7.8 Hz, CH3), 1.31 (m 12
H, 3 CH2 + 2 CH3), 1.50 (m, 2 H, CH2), 2.13 (ddt, 2 H, JH-H = 3.11
Hz, JH-P = 11.00 Hz, JH-H = 8.15 Hz, CH2), 3.67 (m, 2 H, CH2OH),
4.08 (dq, 4 H, JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2 CH2OP), 4.2 (br s, 2
H, 2 OH), 4.36 (br m, 1 H, JH-H = 4.8 Hz, JH-P = 11.70 Hz, CH(OH),
5.53 (ddm, 1 H, JH-H = 3.12 Hz, JH-P = 13.20 Hz, JH-H = 4.80 Hz,
HC=).
13C NMR (CDCl3) (diastereomeric mixture): = 13.88 (s, CH3),
15.88 (d, JC-P = 6.9 Hz, CH3), 16.11 (d, JC-P = 6.5 Hz, CH3), 22.34
(s), 22.42 (s), 27.78 (d, JC-P = 5.7 Hz, CH2), 27.86 (d, JC-P = 6.5 Hz,
CH2), 28.57 (s, CH2), 31.36 (s, CH2), 62.35 (d, JC-P = 6.0 Hz, 2
CH2OP), 65.73 (d, JC-P = 4.0 Hz, CH2OH), 66.05 (d, JC-P = 4.6 Hz,
CH2OH), 69.38 (d, JC-P = 6.5 Hz, CHOH), 69.53 (d, JC-P = 6.5 Hz,
(2R)-5-(Diethylphosphono)nona-3,4-dien-1,2-diol (8g)
Prepared from propargylic alcohol 5g (3.71 g, 0.0175 mol), anhyd
Et2O (75 mL), Et3N (1.92 g, 0.019 mol), and diethyl chlorophos-
phite (2.73 g, 0.0175 mol). Workup and chromatography (CHCl3–
MeOH, 10:1.2) afforded 3.73 g (73%) of 8g. TLC (diastereomeric
mixture): Rf = 0.36, 0.38 (CHCl3–MeOH, 10:1.0).
IR (film): = 1225, 1955, 3380, 367 cm–1.
1H NMR (CDCl3): = 0.91 (t, 3 H, JH-H = 7.9 Hz), 1.35 (m, 8 H, CH2
+ 2 CH3), 1.48 (m, 2 H, CH2), 2.12 (ddt, 2 H, JH-H = 3.2 Hz, JH-P
=
10.76 Hz, JH-H = 8.45 Hz, CH2), 3.61 (m, 2 H, CH2OH), 3.90 (br s,
Synthesis 2001, No. 10, 1539–1545 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Synthesis and Intramolecular Cyclization of Diethylphosphono-Substituted Allenic Glycols
1543
CHOH), 95.02 (d, JC-P = 16.3 Hz, =CH), 95.52 (d, JC-P = 16.4 Hz,
=CH), 95.95 (d, JC-P = 184.6 Hz, =CH-P), 96.11 (d, JC-P = 185.0 Hz,
=CH-P), 208.42 (d, JC-P = 6.8 Hz, =C=), 207.50 (d, JC-P = 6.1 Hz,
=C=).
(3R)-5-(3-Hydroxy-2,3-dihydrofuryl)diethylphosphonotolyl-
methane (2c)
Prepared from allene 8c (3.26 g, 0.01 mol), anhyd CHCl3 (15 mL),
and Et3N (0.1 g, 0.001mol). Workup and chromatography (CHCl3–
MeOH, 10:0.5) afforded 2.25 g (69%) of 2c.
31P NMR (CDCl3) (diastereomeric mixture): = 20.32, 20.46.
Rf = 0.5 (CHCl3–MeOH, 10:0.5).
IR (film): = 1249, 1589, 1614, 1672, 3377 cm–1.
Anal. Calcd for C15H29PO5 (320.36): C, 56.24; H, 9.12; P, 9.67.
Found: C, 56.17; H, 8.99; P, 9.53.
1H NMR (CDCl3) (diastereomeric mixture): = 1.22 (dt, 3 H, JH-H
= 7.3 Hz, JH-P = 1.1 Hz, CH3), 1.31 (m, 3 H, CH3), 2.37 (s, 3 H, CH3),
3.12 (br s, 1 H, JH-H = 7.6 Hz, OH), 3.19 (br s, 1 H, JH-H = 8.0 Hz,
OH), 3.79 (m, 1 H, CH-Ph), 3.93 (dq, 4 H, JH-H = 7.3 Hz, JH-P = 6.9
Hz, 2 CH2OP), 4.13 (dq, 4 H, JH-H = 7.3 Hz, JH-P = 6.9 Hz, 2
CH2OP), 4.24 (m, 2 H, CH2), 4.92 (br m, 1 H, CHOH), 5.31 (m, 1
H, CH=), 7.33 (m, 3 H, Ar-H), 7.48 (m, 2 H, Ar-H).
(3R)-5-(3-Hydroxy-2,3-dihydrofuryl)(diethylphosphono)-
methane (2a); Typical Procedure
To a solution of 8a (2.36 g, 0.01 mol) and anhyd CHCl3 (10 mL)
was added Et3N (0.1 g, 0.001 mol). After stirring for 48 h at 45–50
°C, the reaction mixture was concentrated. Chromatography on sil-
ica gel (CHCl3–MeOH, 10:0.4) yielded 2a (1.96 g, 83%) as an oil.
[ ]546 +79.5 (c 1.1, CH2Cl2); Rf = 0.37 (CHCl3–MeOH, 10:0.4).
IR (film): = 1247, 1678, 3385 cm–1.
13C NMR (CDCl3) (diastereomeric mixture): = 16.17 (d, JC-P = 6.0
Hz, CH3), 16.20 (d, JC-P = 6.0 Hz, CH3), 16.24 (d, JC-P = 6.0 Hz,
CH3), 16.38 (d, JC-P = 6.0 Hz, CH3), 21.31 (s, CH3), 45.32 (d, JC-P
138.9 Hz, CH-P), 45.47 (d, JC-P = 139.2 Hz, CH-P), 62.27 (d, JC-P
7.8 Hz, CH2OP), 62.75 (d, JC-P = 7.4 Hz, CH2OP), 63.05 (d, JC-P
7.6 Hz, CH2OP), 63.15 (d, JC-P = 7.3 Hz, CH2OP), 73.78 (s, HC-
OH), 78.56 (d, JC-P = 2.6 Hz, CH2), 102.54 (d, JC-P = 6.9 Hz, CH=),
102.84 (d, JC-P = 6.4 Hz, CH=), 127.83 (d, JC-P = 2.6 Hz, Tol),
127.94 (d, JC-P = 2.8 Hz, Tol), 128.54 (d, JC-P = 2.3 Hz, Tol), 130.1
(d, JC-P = 3.6 Hz, Tol), 130.10 (d, JC-P = 3.6 Hz, Tol), 134.19 (d,
=
=
=
1H NMR (CDCl3): = 1.31 (dt, 6 H, JH-H = 7.2 Hz, JH-P = 1.9 Hz, 2
CH3), 2.78 (d, 2 H, JH-P = 20.0 Hz, CH2-P), 3.60 (br d, 1 H, JH-H
=
7.6 Hz, OH), 4.11 (dq, 4 H, JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2 CH2OP),
4.27 (m, 2 H, CH2), 4.90 (br m, 1 H, CHOH), 5.13 (m, 1 H, HC=).
13C NMR (CDCl3): = 16.17 (d, JC-P = 6.2 Hz, 2 CH3), 26.56 (d, JC-
P = 140.8 Hz, CH2-P), 62.20 (d, JC-P = 6.3 Hz, 2 CH2OP), 62.32 (d,
JC-P = 6.1 Hz, 2 CH2OP), 73.60 (d, JC-P = 1.7 Hz, CHOH), 78.41 (s,
CH2), 102.26 (d, JC-P = 9.4 Hz, =CH), 153.49 (d, JC-P = 9.5 Hz, =C-
O).
JC-P = 7.1 Hz, Tol), 134.81 (d, JC-P = 7.3 Hz, Ph), 157.84 (d, JC-P =
8.4 Hz, =C-O), 157.92 (d, JC-P = 7.1 Hz, =C-O).
31P NMR (CDCl3) (diastereomeric mixture): = 23.38, 23.61.
31P NMR (CDCl3): = 25.12.
Anal. Calcd for C9H17PO5 (236.20): C, 45.76; H, 7.25; P, 13.11.
Found: C, 45.66; H, 7.00; P, 13.02.
Anal. Calcd for C16H23PO5 (326.33): C, 58.89; H, 7.10; P, 9.49.
Found: C, 59.03; H, 7.10; P, 9.53.
(3R)-5-(3-Hydroxy-2,3-dihydrofuryl)(diethylphosphono)-
(phenyl)methane (2b)
Prepared from allene 8b (3.12 g, 0.01 mol), anhyd CHCl3 (15 mL),
and Et3N (0.1 g, 0.001 mol). Workup and chromatography (CHCl3–
MeOH, 10:0.5) afforded 2.25 g (72%) of 2b.
(3R)-2-[5-(3-Hydroxy-2,3-dihydrofuryl)]-2-(diethyl-
phosphono)ethane-1-ol (2d)
Prepared from allene 8d (2.66 g, 0.01 mol), anhyd CHCl3 (10 mL),
and Et3N (0.1 g, 0.001 mol). Workup and chromatography (CHCl3–
MeOH, 10:0.5) afforded 1.6 g (60%) of 2d.
Rf = 0.48 (CHCl3–MeOH, 10:0.5).
IR (film): = 1254, 1587, 1604, 1671, 3374 cm–1.
1H NMR (CDCl3) (diastereomeric mixture): = 1.10 (dt, 3 H, JH-H
= 7.2 Hz, JH-P = 1.9 Hz, CH3), 1.31 (m, 3 H, CH3), 3.02 (br s, 1 H,
TLC (diastereomeric mixture): Rf = 0.32, 039 (CHCl3–MeOH,
10:0.9).
IR (film): = 1249, 1681, 3380, 3650 cm–1.
1H NMR (CD3OD) (diastereomeric mixture): = 1.32 (dt, 6 H, JH-
H = 7.2 Hz, JH-P = 1.8 Hz, 2 CH3), 3.12 (dt, 1 H, JH-H = 6.9 Hz, JH-P
= 22.0 Hz, CH-P), 3.64 (br s, 2 H, 2OH), 3.98 (m, 2 H, CH2OH),
4.12 (dq, 4 H, JH-H = 7.2 Hz, JH-P = 6.6 Hz, 2 CH2OP), 4.31 (m, 2 H,
JH-H = 7.5 Hz, OH), 3.09 (br s, 1 H, JH-H = 8.1 Hz, OH), 3.73 (m, 1
H, CH-Ph), 3.97 (dq, 4 H, JH-H = 7.2 Hz, JH-P = 7.0 Hz, 2 CH2OP),
4.10 (dq, 4 H, JH-H = 7.2 Hz, JH-P = 6.8 Hz, 2 CH2OP), 4.29 (m, 2 H,
CH2), 4.97 (br m, 1 H, CHOH), 5.35 (m, 1 H, CH=), 7.31 (m, 3 H,
Ph), 7.48 (m, 2 H, Ph).
CH2), 4.91 (br m, 1 H, CHOH), 5.24 (dd, 1 H, JH-H = 2.6 Hz, JH-P
=
4.2 Hz, CH=).
13C NMR (CDCl3) (diastereomeric mixture): = 16.15 (d, JC-P = 6.0
Hz, 2 CH3), 16.19 (d, JC-P = 6.0 Hz, CH3), 16.35 (d, JC-P = 6.0 Hz, 2
CH3), 16.39 (d, JC-P = 6.0 Hz, CH3), 45.45 (d, JC-P = 138.2 Hz, CH-
P), 45.47 (d, JC-P = 139.4 Hz, CH-P), 62.3 (d, JC-P = 7.9 Hz, CH2OP),
62.78 (d, JC-P = 7.1 Hz, CH2OP), 63.09 (d, JC-P = 7.9 Hz, CH2OP),
13C NMR (CD3OD) (diastereomeric mixture): = 14.65 (d, JC-P
5.7 Hz, CH3), 14.77 (d, JC-P = 5.9 Hz, CH3), 41.29 (d, JC-P = 135.5
Hz, CH-P), 41.45 (d, JC-P = 135.9 Hz, HC-P), 58.00 (s, CH2OH),
58.63 (s, CH2OH), 62.10 (d, JC-P = 6.9 Hz, CH2OP), 62.16 (d,
=
J
J
C-P = 7.0 Hz, CH2OP), 62.23 (d, JC-P = 6.9 Hz, CH2OP), 62.30 (d,
C-P = 6.9 Hz, CH2OP), 72.52 (d, JC-P = 1.9 Hz, HC-OH), 77.26 (s,
63.18 (d, JC-P = 7.1 Hz, CH2OP), 73.81 (s, HCOH), 78.53 (d, JC-P
=
2.5 Hz, CH2), 102.75 (d, JC-P = 6.9 Hz, CH=), 102.81 (d, JC-P = 6.2
Hz, CH=), 127.66 (d, JC-P = 2.7 Hz, Ph), 127.71 (d, JC-P = 2.6 Hz,
Ph), 128.53 (d, JC-P = 2.3 Hz, Ph), 129.4 (d, JC-P = 3.5 Hz, Ph),
129.53 (d, JC-P = 3.7 Hz, Ph), 133.39 (d, JC-P = 7.2 Hz, Ph), 133.53
(d, JC-P = 7.4 Hz, Ph), 157.84 (d, JC-P = 8.4 Hz, =C-O), 157.92 (d,
-CH2-), 78.39 (s, -CH2-), 101.57 (d, JC-P = 9.3 Hz, CH=), 102.42 (d,
JC-P = 9.0 Hz, CH=), 154.37 (d, JC-P = 8.4 Hz, =C-O), 155.34 (d,
JC-P = 9.5 Hz, =C-O).
31P NMR (CDCl3) (diastereomeric mixture): = 25.35, 25.32.
J
C-P = 7.1 Hz, =C-O).
Anal. Calcd for C10H19PO6 (266.23): C, 45.12; H, 7.19; P, 11.63.
Found: C, 45.08; H, 7.12; P, 11.52.
31P NMR (CDCl3) (diastereomeric mixture): = 23.34, 23.53.
Anal. Calcd for C15H21PO5 (312.30): C, 57.69; H, 6.77; P, 9.92.
Found: C, 57.51; H, 6.70; P, 9.82.
(3R)-2-[5-(3-Hydroxy-2,3-dihydrofuryl)-2-(diethylphosphono)-
1-methoxyethane (2e)
Prepared from allene 8e (2.8 g, 0.01 mol), anhyd CHCl3 (15 mL),
and Et3N (0.1 g, 0.001 mol). Workup and chromatography (CHCl3–
MeOH, 10:0.5) afforded 1.45 g (52%) of 2e.
Synthesis 2001, No. 10, 1539–1545 ISSN 0039-7881 © Thieme Stuttgart · New York

1544
V. K. Brel
PAPER
Rf = 0.36 (CHCl3–MeOH, 10:0.5).
IR (film): = 1246, 1672, 3381, 3652 cm–1.
1H NMR (CDCl3) (diastereomeric mixture): = 1.31 (dt, 6 H, JH-H
= 7.1 Hz, JH-P = 1.2 Hz, 2 CH3), 3.10 (dt, 1 H, JH-H = 7.0 Hz, JC-P
21.5 Hz, CH-P), 3.37 (s, 3 H, OCH3), 3.79 (m, 2 H, CH2OH), 3.83
(br s, 1 H, JH-H = 7.8 Hz, OH), 4.10 (dq, 4 H, JH-H = 7.1 Hz, JH-P
1H NMR (CDCl3): = 1.30 (dt, 6 H, JH-H = 7.1 Hz, JH-P = 1.9 Hz, 2
CH3), 3.23 (d, 2 H, JH-P = 20.0 Hz, CH2), 4.08 (dq, 4 H, JH-H = 7.1
Hz, JH-P = 6.8 Hz, 2 CH2OP), 6.25 (m, 1 H, =CH), 6.32 (m, 1 H,
=CH), 7.32 (m, 1 H, =CH-O).
=
13C NMR (CDCl3): = 16.22 (d, JC-P = 6.0 Hz, 2 CH3), 26.54 (d,
JC-P = 143.6 Hz, CH2-P), 62.18 (d, JC-P = 6.6 Hz, 2 CH2OP), 108.08
=
(d, JC-P = 7.5 Hz, =CH), 110.66 (d, JC-P = 3.1 Hz, =CH), 141.79 (d,
JC-P = 3.3 Hz, =CH-O), 145.50 (d, JC-P = 9.6 Hz, =C).
31P NMR (CDCl3): = 24.45.
6.7 Hz, 2 CH2OP), 4.20 (m, 2 H, -CH2-), 4.93 (br m, 1 H, CHOH),
5.20 (dd, 1 H, JH-H = 2.6 Hz, JH-P = 4.2 Hz, CH=).
13C NMR (CDCl3) (diastereomeric mixture): = 16.02 (d, JC-P = 5.9
Hz, 2 CH3), 16.17 (d, JC-P = 5.9 Hz, 2 CH3), 42.03 (d, JC-P = 136.4
Hz, HC-P), 42.27 (d, JC-P = 136.6 Hz, HC-P), 58.07 (s, OCH3),
59.72 (s, CH2OCH3), 59.85 (s, CH2OCH3), 62.12 (d, JC-P = 6.9 Hz,
CH2OP), 62.17 (d, JC-P = 6.9 Hz, CH2OP), 62.21 (d, JC-P = 6.9 Hz,
CH2OP), 62.24 (d, JC-P = 6.9 Hz, CH2OP), 72.41 (d, JC-P = 2.0 Hz,
HC-OH), 72.41 (d, JC-P = 2.0 Hz, HCOH), 77.31 (s, -CH2-), 78.45
(s, -CH2-), 101.31 (d, JC-P = 9.2 Hz, CH=), 102.53 (d, JC-P = 9.3 Hz,
CH=), 154.13 (d, JC-P = 8.5 Hz, =C-O), 155.30 (d, JC-P = 9.4 Hz, =C-
O).
Anal. Calcd for C9H15PO4 (218.20): C, 49.54; H, 6.93; P, 14.20.
Found: C, 49.46; H, 6.80; P, 14.09.
Diethylphosphono(2-furyl)phenylmethane (3b)
Prepared from a solution of dihydrofuran 2b (0.31 g, 0.001 mol) in
CHCl3 (10 mL), and p-toluenesulfonic acid (86 mg, 0.0005 mol).
Workup and chromatography (CHCl3–MeOH, 10:0.3) afforded
0.26 g (89%) of 3b.
Rf = 0.79 (CHCl3–MeOH, 10:0.5).
IR (film): = 1255, 1575, 1564, 1602 cm–1.
31P NMR (CDCl3) (diastereomeric mixture): = 25.61, 25.67.
Anal. Calcd for C11H21PO6 (280.25): C, 47.14; H, 7.55; P, 11.05.
Found: C, 47.19; H, 7.50; P, 11.20.
1H NMR (CDCl3): = 1.11 (dt, 3 H, JH-H = 7.3 Hz, JH-P = 1.2 Hz,
CH3), 1.21 (dt, 3 H, JH-H = 7.1 Hz, JH-P = 1.2 Hz, CH3), 4.00 (m, 4
H, 2 CH2OP), 4.55 (d, 2 H, JH-P = 25.3 Hz, CH-P), 6.34 (m, 1 H,
=CH), 6.51 (m, 1 H, =CH), 7.32 (m, 5 H, Ar), 7.48 (m, 1 H, =CH-
O).
(3R)-1-[5-(3-hydroxy-2,3-dihydrofuryl)-1-(diethylphosphono)-
propane-2-ol (2f)
Prepared from allene 8f (2.8 g, 0.01 mol), anhyd CHCl3 (12 mL),
and Et3N (0.1 g, 0.001 mol). Workup and chromatography (CHCl3–
MeOH, 10:1.0) afforded 1.54 g (55%) of 2f.
13C NMR (CDCl3): = 16.21 (d, JC-P = 5.8 Hz, CH3), 16.32 (d, JC-P
= 5.8 Hz, CH3), 45.28 (d, JC-P = 140.1 Hz, CH-P), 62.89 (d, JC-P
7.0 Hz, CH2OP), 62.96 (d, JC-P = 7.0 Hz, CH2OP), 108.72 (d, JC-P
=
=
TLC (diastereomeric mixture): Rf = 0.40, 0.42 (CHCl3–MeOH,
10:1).
IR (film): = 1245, 1678, 3358, 3662 cm–1.
1H NMR (CDCl3) (diastereomeric mixture): = 1.31 (m, 9 H,
3CH3), 2.80, 2.92 (dd, 1 H, JH-H = 6.0, 6.6 Hz, JC-P = 22.0 Hz, CH-
P), 4.10 (m, 6 H, 2 CH2OP + 2 OH), 4.25 (m, 2 H, -CH2-), 4.56 (br
m, 1 H, CH3-CHOH), 4.87 (br m, 1 H, CHOH), 5.15, 5.25 (dd, 1 H,
5.1 Hz, =CH), 110.63 (d, JC-P = 2.1 Hz, =CH), 127.48 (d, JC-P = 2.8
Hz, Ph), 128.53 (d, JC-P = 2.3 Hz, Ph), 129.38 (d, JC-P = 6.3 Hz, Ph),
134.41 (d, JC-P = 6.4 Hz, Ph), 142.79 (d, JC-P = 2.2 Hz, =CH-O),
149.73 (d, JC-P = 2.8 Hz, =C).
31P NMR (CDCl3): = 23.68.
Anal. Calcd for C15H19PO4 (294.29): C, 61.22; H, 6.51; P, 10.53.
Found: C, 61.18; H, 6.45; P, 10.46.
JH-H = 2.7 Hz, JH-P = 3.6 Hz, CH=).
13C NMR (CDCl3) (diastereomeric mixture): = 16.14 (d, JC-P = 6.2
Hz, CH3), 16.20 (d, JC-P = 6.0 Hz, CH3), 21.06 (d, JC-P = 10.0 Hz,
CH3), 21.15 (d, JC-P = 9.9 Hz, CH3), 21.43 (d, JC-P = 8.0 Hz, CH3),
46.26 (d, JC-P = 136.16 Hz, HC-P), 46.47 (d, JC-P = 136.16 Hz, HC-
P), 46.65 (d, JC-P = 136.16 Hz, HC-P), 62.17 (d, JC-P = 6.9 Hz,
CH2OP), 62.40 (d, JC-P = 6.9 Hz, CH2OP), 62.83 (d, JC-P = 6.8 Hz,
CH2OP), 62.87 (d, JC-P = 6.7 Hz, CH2OP), 65.93 (d, JC-P = 3.0 Hz,
HCOH), 65.86 (d, JC-P = 3.0 Hz, HCOH), 66.05 (d, JC-P = 2.9 Hz,
HCOH), 73.17 (d, JC-P = 1.8 Hz, HCOH), 73.20 (d, JC-P = 1.8 Hz,
HCOH), 73.37 (d, JC-P = 1.8 Hz, HCOH), 78.07 (s, -CH2-), 78.16 (s,
-CH2-), 78.23 (s, -CH2-), 103.16 (d, JC-P =8.2 Hz, CH=), 103.46 (d,
JC-P = 9.5 Hz, CH=), 104.07 (d, JC-P = 8.6 Hz, CH=), 154.94 (d,
Diethylphosphono(2-furyl)tolylmethane (3c)
Prepared from a solution of dihydrofuran 2c (0.33 g, 0.001 mol) in
CHCl3 (10 mL), and p-toluenesulfonic acid (86 mg, 0.0005 mol).
Workup and chromatography (CHCl3–MeOH, 10:0.3) afforded
0.27 g (88%) of 3c.
Rf = 0.80 (CHCl3–MeOH, 10:0.5).
IR (film): = 1255, 1575, 1564, 1598, 1602 cm–1.
1H NMR (CDCl3): = 1.11 (dt, 3 H, JH-H = 7.3 Hz, JH-P = 1.2 Hz,
CH3), 1.21 (dt, 3 H, JH-H = 7.1 Hz, JH-P = 1.2 Hz, CH3), 2.38 (s, 3 H,
CH3), 4.0 (m, 4 H, 2 CH2OP), 4.55 (d, 2 H, JH-P = 25.3 Hz, CH-P),
6.34 (m, 1 H, =CH), 6.51 (m, 1 H, =CH, Tol), 7.32 (m, 5 H, Tol),
7.48 (m, 1 H, =CH-O).
JC-P = 7.6 Hz, =C-O), 155.41 (d, JC-P = 8.1 Hz, =C-O), 155.67 (d,
JC-P = 8.1 Hz, =C-O).
31P NMR (CDCl3) (diastereomeric mixture): = 25.65, 25.89,
25.22, 26.35.
13C NMR (CDCl3): = 16.30 (d, JC-P = 5.9 Hz, 2 CH3), 16.32 (d,
JC-P = 5.8 Hz, CH3), 21.25 (s, CH3), 46.03 (d, JC-P = 139.3 Hz, CH-
P), 62.63 (d, JC-P = 7.0 Hz, CH2OP), 62.86 (d, JC-P = 7.0 Hz,
CH2OP), 108.34 (d, JC-P = 5.3 Hz, =CH), 109.38 (d, JC-P = 2.1 Hz,
=CH), 127.48 (d, JC-P = 2.8 Hz, Tol), 128.53 (d, JC-P = 2.3 Hz, Tol),
129.38 (d, JC-P = 6.3 Hz, Tol), 134.41 (d, JC-P = 6.4 Hz, Tol), 142.79
(d, JC-P = 2.2 Hz, =CH-O), 149.73 (d, JC-P = 2.8 Hz, =C).
Anal. Calcd for C11H21PO6 (280.25): C, 47.14; H, 7.55; P, 11.05.
Found: C, 47.19; H, 7.50; P, 11.20.
Diethylphosphono(2-furyl)methane (3a); Typical Procedure
To a solution of 2a (0.24 g, 0.001 mol) in CHCl3 (10 mL) was added
p-toluenesulfonic acid (86 mg, 0.0005 mol). After stirring for 0.5 h
at 40–45 °C, the reaction mixture was concentrated in vacuo. Chro-
matography on silica gel (CHCl3–MeOH, 10:0.4) yield 3a (0.2 g,
90%) as an oil.
31P NMR (CDCl3): = 23.72.
Anal. Calcd for C16H21PO4 (308.31): C, 62.33; H, 6.87; P, 10.05.
Found: C, 62.39; H, 6.84 ; P, 10.17.
2-(Diethylphosphono)-2-(2-furyl)ethane-1-ol (3d)
Prepared from a solution of dihydrofuran 2d (0.27 g, 0.001 mol) in
CHCl3 (10 mL), and p-toluenesulfonic acid (86 mg, 0.0005 mol).
Rf = 0.72 (CHCl3–MeOH, 10:0.4).
IR (film): = 1260, 158, 1490 cm–1.
Synthesis 2001, No. 10, 1539–1545 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Synthesis and Intramolecular Cyclization of Diethylphosphono-Substituted Allenic Glycols
1545
Workup and chromatography (CHCl3–MeOH, 10:0.5) afforded
Hz, CH3), 21.52 (d, JC-P = 13.1 Hz, CH3), 44.87 (d, JC-P = 139.8 Hz,
0.22 g (88%) of 3d.
CH-P), 46.59 (d, JC-P = 137.5 Hz, CH-P), 62.05 (d, JC-P = 7.2 Hz,
CH2OP), 62.43 (d, JC-P = 6.9 Hz, CH2OP), 62.98 (d, JC-P = 7.0 Hz,
CH2OP), 63.29 (d, JC-P = 7.0 Hz, CH2OP), 65.68 (d, JC-P = 3.5 Hz,
CHOH), 66.91 (d, JC-P = 2.8 Hz, CHOH), 108.64 (d, JC-P = 6.7 Hz,
=CH), 109.85 (d, JC-P = 6.3 Hz, =CH), 110.60 (d, JC-P = 2.8 Hz,
=CH), 110.76 (d, JC-P = 2.7 Hz, =CH), 141.89 (d, JC-P = 3.0 Hz,
=CH-O), 142.03 (d, JC-P = 3.0 Hz, =CH-O), 146.49 (d, JC-P = 4.4 Hz,
=C), 148.00 (d, JC-P = 8.58 Hz, =CH-).
Rf = 0.66 (CHCl3–MeOH, 10:0.9).
IR (film): = 1258, 1583, 1599, 3372 cm–1.
1H NMR (CDCl3): = 1.23 (dt, 3 H, JH-H = 7.1 Hz, JH-P = 1.6 Hz,
CH3), 1.31 (dt, 3 H, JH-H = 7.0 Hz, JH-P = 1.4 Hz, CH3), 3.45 (br s, 1
H, OH), 3.53 (dt, 1 H, JH-P = 22.4 Hz, CH-P), 3.95 (m, 2 H, CH2),
4.08 (dq, 4 H, JH-H = 7.1 Hz, JH-P = 6.6 Hz, 2 CH2OP), 6.35 (m, 2 H,
2 =CH), 7.39 (m, 1 H, =CH-O).
31P NMR (CDCl3): = 25.09.
13C NMR (CDCl3): = 16.08 (d, JC-P = 5.9 Hz, CH3), 16.12 (d, JC-P
Anal. Calcd for C11H19PO5 (262.24): C, 50.38; H, 7.30; P, 11.81.
Found: C, 50.47; H, 7.35; P, 11.80.
= 5.9 Hz, CH3), 41.24 (d, JC-P = 138.5 Hz, CH-P), 60.57 (d, JC-P
1.6 Hz, HOCH2), 62.21 (d, JC-P = 6.9 Hz, CH2OP), 62.67 (d, JC-P
6.9 Hz, CH2OP), 108.26 (d, JC-P = 6.9 Hz, =CH), 110.54 (d, JC-P
2.9 Hz, =CH), 141.85 (d, JC-P = 3.1 Hz, =CH-O), 147.85 (d, JC-P
7.9 Hz, C=).
=
=
=
=
References
(1) (a) Claesson, A.; Olsson, L.-I.In The Chemistry of Allenes,
Vol. 3; Landor, S. R., Ed.; Academic Press: London, 1982,
737. (b) Fuks, R.; Viehe, H. G.In The Chemistry of
Acetylenes; Viehe, H. G., Ed.; Marcel Dekker: New York,
1969, 425. (c) Padwa, A.; Meske, M.; Ni, Z. Tetrahedron
1995, 51, 89.
(2) (a) Marshall, J. A.; Sehon, C. A. J. Org. Chem. 1994, 59,
7169. (b) Walkup, R. D.; Kim, S. W. J. Org. Chem. 1994,
59, 7169.
(3) (a) Claesson, A.; Olsson, L.-I.In The Chemistry of Allenes,
Vol. 2; Landor, S. R., Ed.; Academic Press: London, 1982,
369. (b) Nikam, S. S.; Chu, K.-H.; Wang, K. K. J. Org.
Chem. 1986, 51, 745. (c) Ma, S.; Shi, Z. J. Org. Chem. 1998,
63, 6387. (d) Marshall, J. A.; Yu, B.-C. J. Org. Chem. 1994,
59, 324. (e) Hormuth, S.; Reissig, H.-U. J. Org. Chem. 1994,
59, 67.
(4) (a) Marshall, J. A.; Sehon, C. A. J. Org. Chem. 1995, 60,
5967. (b) Marshall, J. A.; Bartley, G. S.; Wallace, E. M. J.
Org. Chem. 1996, 61, 5729.
31P NMR (CDCl3): = 25.2.
Anal. Calcd for C10H17PO5 (248.21): C, 48.39; H, 6.90; P, 12.48.
Found: C, 48.35; H, 6.84; P, 12.42.
2-(Diethylphosphono)-2-(2-furyl)-1-methoxyethane (3e)
Prepared from a solution of dihydrofuran 2e (0.28 g, 0.001 mol) in
CHCl3 (10 mL), and p-toluenesulfonic acid (86 mg, 0.0005 mol).
Workup and chromatography (CHCl3–MeOH, 10:0.5) afforded
0.17 g (65%) of 3e.
Rf = 0.43 (CHCl3–MeOH, 10:0.5).
IR (film): = 1255, 1580, 1602 cm–1.
1H NMR (CDCl3): = 1.20 (dt, 3 H, JH-H = 7.0 Hz, JH-P = 1.8 Hz,
CH3), 1.31 (dt, 3 H, JH-H = 7.0 Hz, JH-P = 1.8 Hz, CH3), 3.29 (s, 3 H,
CH3), 3.42 (dt, 1 H, JH-P = 22.0 Hz, CH-P), 3.98 (m, 2 H, CH2), 4.11
(dq, 4 H, JH-H = 7.0 Hz, JH-P = 6.7 Hz, 2 CH2OP), 6.29 (m, H, =CH),
6.47 (m, H, =CH), 7.34 (m, 1 H, O-HC=).
13C NMR (CDCl3): = 16.05 (d, JC-P = 6.0 Hz, CH3), 16.11 (d, JC-P
= 6.0 Hz, CH3), 42.71 (d, JC-P = 136.3 Hz, CH-P), 57.42 (s, OCH3),
59.12 (d, JC-P = 2.1 Hz, CH2OCH3), 62.68 (d, JC-P = 7.0 Hz, CH2OP),
62.81 (d, JC-P = 6.9 Hz, CH2OP), 109.03 (d, JC-P = 6.9 Hz, =CH),
110.26 (d, JC-P = 3.0 Hz, =CH), 142.75 (d, JC-P = 3.0 Hz, =CH-O),
148.94 (d, JC-P = 8.0 Hz, =C).
(5) Pravia, K.; White, R.; Fodda, R.; Maynard, D. F. J. Org.
Chem. 1996, 61, 6931.
(6) Brel, V. K. Synthesis 1999, 463.
(7) (a) Brel, V. K. Synth. Commun. 1999, 29, 3869.
(b) Alabugin, I. V.; Brel, V. K. Phosphorus, Sulfur and
Silicon 1996, 1, 61. (c) Alabugin, I. V.; Brel, V. K. Usp.
Khim. 1997, 66, 225. (d) Chem. Abstr. 1998, 128, 114977r.
(8) (a) Brel, V. K.; Abramkin, E. V.; Chekhlov, A. N.;
Martynov, I. V. Dokl. Akad. Nauk SSSR 1990, 312, 619.
(b) Chem. Abstr. 1991, 114, 12251n. (c) Brel, V. K.
Synthesis 1998, 710. (d) Zefirov, N. S.; Koz’min, A. S.;
Kasumov, T. M.; Potekhin, K. A.; Sorokin, V. D.; Brel, V.
K.; Abramkin, E. V.; Struchkov, Y. T.; Zhdankin, V. V.;
Stang, P. J. J. Org. Chem. 1992, 57, 2433.
(9) Schmid, C. R.; Bryant, J. D.; Dowlatzedah, M.; Phillips, J.
L.; Prather, D. E.; Schantz, R. D.; Sear, N. L.; Vianco, C. S.
J. Org. Chem. 1991, 56, 4056.
(10) Chittenden, G. J. F. Carbohydr. Res. 1980, 84, 350.
(11) Zhong, Y.-L.; Shing, T. K. M. J. Org. Chem. 1997, 62, 2622.
(12) Brandsma, L. Preparative Acetylenic Chemistry; Elsevier:
Amsterdam, 1988, 265.
31P NMR (CDCl3): = 25.8.
Anal. Calcd for C11H19PO5 (262.24): C, 50.38; H, 7.30; P, 11.81.
Found: C, 50.27; H, 7.18; P, 11.72.
1-(Diethylphosphono)-1-(2-furyl)propane-2-ol (3f)
Prepared from a solution of dihydrofuran 2f (0.28 g, 0.001 mol) in
CHCl3 (10 mL), and p-toluenesulfonic acid (86 mg, 0.0005 mol).
Workup and chromatography (CHCl3–MeOH, 10:0.8) afforded 1.6
g (60%) of 3f.
TLC (diastereomeric mixture): Rf = 0.63, 0.67 (CHCl3–MeOH,
10:0.8).
IR (film): = 1250, 1585, 1600 cm–1.
1H NMR (CDCl3): = 1.15 (m, 3 H, JH-H = 1.6, 0.6 Hz, JH-P = 1.8,
6.3, 6.7 Hz, CH3), 1.31 (m, 6 H, JH-H = 7.1 Hz, JH-P = 1.0 Hz, 2 CH3),
2.93 (dd, 1 H, JH-H = 0.52 Hz, JH-p = 15.3 Hz, CH-P), 3.26 (dd, JH-H
= 8.9 Hz, JH-P = 20.8 Hz, CH-P), 3.32 (dd, JH-H = 2.7 Hz, JH-P = 24.1
Hz, CH-P), 3.65 (br s, 1 H, OH), 3.80 (m, 1 H, CH-OH), 4.11 (m, 4
H, 2CH2OP), 4.40 (m, 1 H, CHOH), 6.27, 6.49 (m, 1 H, =CH), 6.35,
6.40 (m, 1 H, =CH), 7.38, 7.40 (m, 1 H, O-HC=).
(13) Mark, V. In Mechanism of Molecular Migrations, Vol. 3;
Thyagajaran, B. S., Ed.; Wiley: New York, 1969, 320–431.
(14) Wolfgang, R.In The Chemistry of Allenes, Vol. 2; Landor, S.
R., Ed.; Academic Press: London, 1982, 832–847.
(15) Langlois, N.; Choudhury, P. K. Tetrahedron Lett. 1999, 40,
2525.
13C NMR (CDCl3): = 16.15 (d, JC-P = 5.9 Hz, CH3), 16.21 (d, JC-P
= 5.9 Hz, CH3), 16.26 (d, JC-P = 6.0 Hz, CH3), 20.83 (d, JC-P = 13.5
(16) Perrin, D. D.; Armarego, W. L. F.; Perin, D. R. Purification
of Laboratiry Chemicals; Pergamon Press: New York, 1980.
Synthesis 2001, No. 10, 1539–1545 ISSN 0039-7881 © Thieme Stuttgart · New York