Phosphonylated thiocarbonyl ylides from the reaction of aromatic thioketones with diethyl diazomethylphosphonates

Article abstract of DOI:10.1016/j.tet.2006.05.062

The reaction of diazomethylphosphonates with aromatic thioketones at -65 °C to room temperature yields 2,5-dihydro-1,3,4-thiadiazole-2-phosphonates, which eliminates N₂ to give phosphonylated thiocarbonyl ylides as reactive intermediates. These sulfur-centered 1,3-dipoles undergo typical reactions of thiocarbonyl ylides, i.e., 1,3-dipolar cycloadditions, cyclodimerization, and electrocyclic ring closure, depending on the involved thioketone and, therefore, on the reaction conditions. In the case of the most reactive thiofluorenone, the phsophonylated thiocarbonyl methanide can be intercepted with thiobenzophenone, a phosphonodithioformate, and tetracyanoethylene. In the absence of such reactive dipolarophiles, cyclodimerization occurs to give the corresponding 1,4-dithiane.

Full text of DOI:10.1016/j.tet.2006.05.062

Tetrahedron 62 (2006) 7776–7782
Phosphonylated thiocarbonyl ylides from the
reaction of aromatic thioketones with
diethyl diazomethylphosphonates
a,*
a,*
a
Stanislaw Lesniak, Grzegorz Mloston, Katarzyna Urbaniak, Piotr Wasiak,
a,y
b
Anthony Linden and Heinz Heimgartner
b,
*
a
Department of Organic and Applied Chemistry, University of Ł oꢀ d ꢀz , Narutowicza 68, PL-90-136 Ł oꢀ d ꢀz , Poland
Institute of Organic Chemistry, University of Z u€ rich, Winterthurerstrasse 190, CH-8057 Z u€ rich, Switzerland
b
Received 20 April 2006; revised 16 May 2006; accepted 24 May 2006
Available online 16 June 2006
ꢁ
Abstract—The reaction of diazomethylphosphonates with aromatic thioketones at ꢀ65 C to room temperature yields 2,5-dihydro-1,3,4-
thiadiazole-2-phosphonates, which eliminates N
1
2
to give phosphonylated thiocarbonyl ylides as reactive intermediates. These sulfur-centered
,3-dipoles undergo typical reactions of thiocarbonyl ylides, i.e., 1,3-dipolar cycloadditions, cyclodimerization, and electrocyclic ring
closure, depending on the involved thioketone and, therefore, on the reaction conditions. In the case of the most reactive thiofluorenone,
the phsophonylated thiocarbonyl methanide can be intercepted with thiobenzophenone, a phosphonodithioformate, and tetracyanoethylene.
In the absence of such reactive dipolarophiles, cyclodimerization occurs to give the corresponding 1,4-dithiane.
Ó 2006 Elsevier Ltd. All rights reserved.
1
. Introduction
formation of a mixture of 6 and methyl 3,3-diphenylacrylate,
which is the product of desulfurization of thiirane 7 (Scheme
1). The later reported reaction of diazoacetate with 9H-xan-
thene-9-thione (2c), which is less reactive than 2a, in THF at
60 C yielded only the corresponding acrylate. In the same
paper, the reaction of ethyl diazoacetate with sterically hin-
dered cycloaliphatic thiones, derived from 2,2,4,4-tetra-
methylcyclobutane-1,3-dione, was reported to give only
thiiranes. In a reaction of adamantanethione with ethyl
1
In contrast to the widely explored diazoacetates, diazo-
methylphosphonates are rarely used in 1,3-dipolar cyclo-
additions. Only recently, reactions with imines to give
ꢁ
8
4
,5-dihydro-1,2,3-thiazole-4-phosphonates or aziridine-2-
2
phosphonates have been reported. It is well established
that reactions of diazo compounds with thiocarbonyl di-
polarophiles lead to 2,5-dihydro-1,3,4-thiadiazoles, which
3
,4
offer a convenient access to reactive thiocarbonyl ylides.
Diazoacetates were also applied in this reaction, even at
a time when the reaction mechanism for the formation of
1
5 o
C
N
N
Ph
Ph
N2CHCO2Me
+
Ph2C=S
5
,6
CO2Me
thiiranes and 1,3-dithiolanes was not known. The reaction
of methyl diazoacetate (1) with thiobenzophenone (2a)
was a key experiment in the elucidation of the reaction
mechanism for the formation of 1,3-dithiolanes (so-called
S
3
1
2a
-
N2
Ph
7
Sch €o nberg products). Interestingly, the regioisomeric 1,3-
Ph
S
CO Me
2
dithiolanes 5 and 6 were formed in a ratio of 1:1. The anal-
ogous reaction with 9H-fluorene-9-thione (2b) was reported
to give the corresponding product of type 5 exclusively.
4
2a
ꢁ
2a
Heating of the ‘labile’ isomer 5 to 100 C resulted in the
Ph
Ph
Ph
Ph
CO2Me
S
Ph
Ph
Ph
S
Keywords: Diazo compounds; Thioketones; Thiocarbonyl ylides; [2+3]
Cycloadditions; Cyclodimerization; X-ray crystallography.
S
2
CO Me
S
S
Ph
Ph
7
CO2Me
6
*
Corresponding authors. Tel.: +48 42 6355761; fax: +48 42 6355380
S.L., G.M.); tel.: +41 44 6354282; fax +41 44 6356836 (H.H.); e-mail
(
Ph
addresses: slesniak@chemul.uni.lodz.pl; gmloston@uni.lodz.pl; heimgart@
oci.unizh.ch
In part from the Ph.D. thesis of P.W., University of q o´ d z´ , 2004.
5
y
Scheme 1.
0
040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.05.062

S. Lesniak et al. / Tetrahedron 62 (2006) 7776–7782
7777
diazoacetate, which was catalyzed by LiClO , the sterically
4
8
less hindered 1,3-dithiolane of type 6 was the sole product.
More complex reaction mixtures were obtained when ethyl
diazoacetate was reacted with 4,4-disubstituted 1,3-thia-
zole-5(4H)-thiones.
9
Phosphonylated thiocarbonyl ylides are attractive building
blocks for the synthesis of phosphonylated sulfur hetero-
cycles, which are difficult to access by other methods. Re-
cently, these versatile dipolar species were generated from
10,11
diazomethane and dialkyl phosphonodithioformates.
In
the present paper, a different approach based on [2+3] cyclo-
addition of diazomethylphosphonates (8) with aromatic
thioketones is described.
2
. Results and discussion
Unlike the reaction with methyl diazoacetate (1, Scheme 1),
the blue solution of thiobenzophenone (2a) in THF decolor-
ized within ca. 30 min of the addition of an equimolar
1
3
Figure 1. ORTEP-plot of the molecular structure (conformation A) of 11a
(arbitrary numbering of atoms, 50% probability ellipsoids).
ꢁ
amount of 8a at ꢀ15 C, which indicates that 8a is sig-
nificantly more reactive than 1. During the reaction, a slow
evolution of nitrogen was observed. At room temperature,
addition of 8a to a solution of 2a or vice versa was accom-
panied by a vigorous gas evolution. In the crude reaction
mixture, a new product 11a and unconsumed 8a were found
According to the reactivity scale elaborated for the [2+3]
cycloaddition of diphenyldiazomethane and C]S dipolaro-
philes, 9H-fluoren-9-thione (2b) is approximately 100ꢂ
12
more reactive than 2a. The enhanced reactivity of 2b
1
in a ratio of ca. 1:1 ( H NMR). By trituration with hexane,
11a was isolated as a colorless solid. Its structure was estab-
lished as symmetrical 1,3-dithiolane on the basis of its H
was confirmed in the reaction with 8a. The decolorization
of the 1:1 mixture occurred smoothly at ꢀ65 C without
ꢁ
evolution of nitrogen. The evolution of N started between
1
2
1
3
and C NMR spectra (Scheme 2). The most indicative sig-
nal is that for C(4) and C(5) appearing at 79.6 ppm
ꢁ
the crude mixture showed the presence of a single product
ꢀ
50 and ꢀ45 C, and after warming to room temperature,
3
(
nate group, is located at 40.8 ppm as a doublet with
JCP¼7 Hz). The signal of C(2), which bears the phospho-
1
( H NMR), with a characteristic signal at 4.84 ppm
(
2
3
JHP¼24.9 Hz, JHP¼12.6 Hz). The integration of this
1
JCP¼150.9 Hz. An analogous result was obtained in the
signal, which originates from 8a, and the aromatic protons
reveals a ratio of 1:8, which indicates that the starting
materials reacted in a 1:1 ratio. The elemental analysis
was in accordance with the values for the thiocarbonyl ylide
case of dimethyl diazomethylphosphonate (8b).
O
N
N
-
15 o
C
Ph
Ph
10c, while the CIMS showed the [M+1] peak at m/z 693.
+
N CH-P(OR) + Ph2C=S
2
2
PO(OR)2
THF
S
Therefore, the isolated product is a dimer of 10c. Finally,
the structure of the compound was established by X-ray
crystallography (Fig. 2) as trans-1,4-dithiane-2,3-diphos-
phonate 12 (Scheme 3). The six-membered heterocycle
8
a R = Et
b R = Me
2a
9a R = Et
b R = Me
-
N2
Ph
S
Ph
Ph
Ph
+2a
rt
PO(OR)2
Ph
S
PO(OR)2
S
Ph
1
1a R = Et
b R = Me
10a R = Et
b R = Me
Scheme 2.
Finally, the structure of 11a was established by X-ray crys-
tallography (Fig. 1). The five-membered heterocycle has
a half-chair conformation twisted on S(1)–C(5). One ethyl
group is disordered over two conformations.
In comparison with the result obtained with 1 (Scheme 1),
the most important difference is that only the sterically
more congested 1,3-dithiolane was formed, i.e., the [2+3]
cycloaddition of 10 with 2a occurs with high regio-
selectivity.
1
3
Figure 2. ORTEP-plot of the molecular structure (conformation A) of 12
(arbitrary numbering of atoms, 50% probability ellipsoids).

7778
S. Lesniak et al. / Tetrahedron 62 (2006) 7776–7782
has a chair conformation with the phosphonate substituents
in equatorial positions. The fluorene groups are quite planar.
The terminal methyl group of one ethoxy group is disordered
over two conformations.
S
PO(OEt)2
Ph C=S
2
2a
(NC) C=C(CN)
10c
2
2
S
15
NC
Ph
CN
PO(OEt)2
Ph
NC
NC
S
S
N
N
+
THF
65
8a
Ar
Ar
PO(OEt)2
PO(OEt)2
S
S
o
-
C
O
S
2
b
9c
(
i-PrO)2P
13
SMe
THF
-
N2
o
11d
16
-
45
C
PO(Oi-Pr)2
Ar
Ar
MeS
S
S
S
Ar
Ar
Ar
+2b
rt
PO(OEt)2
PO(OR)2
Ar
S
PO(OEt)2
S
1
1c
10c
1
4
rt
Ar
Ar
=
Scheme 4.
Ar
PO(OEt)2
S
S
Ar
H
Ar
PO(OEt)2
H
the dimer could be detected. Therefore it can be concluded
that 13 is a superior dipolarophile, comparable with the
frequently used 2a and 2b.
Ar
1
2
Scheme 3.
From the selected C,C-dipolarophiles, i.e., maleic anhy-
dride, N-cyclohexylmaleimide, and tetracyanoethane, only
the latter was able to trap 10c to yield tetrahydrothiophene
16 (Scheme 4). No formation of any side-product was
observed in this reaction.
The experiment shows that the highly reactive 2b already
undergoes the [2+3] cycloaddition with 8a at ꢀ65 C to
ꢁ
give regioselectively the 2,5-dihydro-1,3,4-thiadiazole 9c,
which is stable at this temperature. The decomposition starts
only at ca. ꢀ45 C, and thiocarbonyl ylide 10c is formed as
ꢁ
a transient species. In the absence of any intercepting agent,
It is well known that 9H-xanthene-9-thione (2c) and 9H-
thioxanthene-9-thione (2d) belong to the moderately reac-
tive aromatic thioketones. With 8a in THF, 2c reacted
1
0c dimerizes regio- and stereoselectively to give 12 exclu-
1
2
sively. Under these conditions, 1,3-dipolar electrocycliza-
tion to the corresponding thiirane is completely suppressed
by the dimerization process. The mechanism of the head-
to-head dimerization can be formulated in line with earlier
slowly at room temperature with evolution of nitrogen.
The mixture decolorized within 24 h and gave two products
1
1
1e and 18a in a ratio of 5:1 (Scheme 5). In the H NMR
1
1
4
spectrum, 11e showed a doublet at 5.53 ppm ( JHP¼6.1 Hz),
results to occur via a 1,6-diradical.
whereas the corresponding signal of 18a appeared at
5
1
.92 ppm ( J ¼8.9 Hz). The same products were obtained
HP
When 2b was added to a freshly prepared solution of 9c
at ꢀ65 C and the mixture was subsequently warmed to
ꢁ
room temperature, typical workup by crystallization gave
when the reaction was carried out in boiling THF, but in this
case, the ratio was determined as 2:3. Finally, after addition
of 2c to a boiling solution of 8a in toluene, only the
the 1,3-dithiolane-2-phosphonate 11c in almost quantitative
yield (Scheme 3). Similar to 11a, in the H NMR spectrum,
1
2
H–C(2) appears at 5.52 ppm as a doublet ( J ¼6.6 Hz),
HP
S
1
Ar'
and C(2) appears as a doublet at 43.6 ppm ( J ¼152.4 Hz).
CP
+
8a
1
As no dimer 12 could be detected in the crude mixture ( H
Ar'
S
PO(OEt)2
THF
NMR), thiocarbonyl ylide 10c must have been trapped
completely by the ‘superdipolarophile’ 2b. A similar result
was obtained with 2a instead of 2b. Also in this case, no
dimerization was observed, and the structure of the mixed
1,3-dithiolane 11d was attributed to the product isolated
by crystallization (Scheme 4).
X
2c X = O
d X = S
10d
e
+2c
Ar'
Ar'
S
S
Ar'
Ar'
PO(OEt)2
PO(OEt)2
In addition to the thioketones 2a and 2b, S-methyl diiso-
propyl phosphonodithioformate (13) was tested as a C]S
dipolarophile. Recently, it has been shown that 13 is an effi-
cient interceptor of aromatic and cycloaliphatic thiocarbonyl
11e
X
X
S
-S
PO(OEt)2
Ar'
Ar'
=
O
1
5
ꢁ
17a X = O
b X = S
18a X = O
b X = S
S-methanides. The reaction with 10c, generated at ꢀ45 C,
1
6
led to the expected 1,3-dithiolane-2,4-diphosphonate 14
Scheme 4). Again, neither the corresponding thiirane nor
(
Scheme 5.

S. Lesniak et al. / Tetrahedron 62 (2006) 7776–7782
7779
vinylphosphonate 18a was formed. In this system, the inter-
mediate 10d undergoes an electrocyclic ring closure to give
were recorded in KBr pellets or as films on a Thermo-
Nicolet Nexus FTIR spectrometer. Low- and high-resolu-
tion EI mass spectra (MS and HRMS) were taken on a
Finnigan MAT 95 spectrometer at 70 eV. Melting points
(uncorrected) were determined in capillary or on a Bo €e tius
apparatus.
1
7a or enter a competitive [2+3] cycloaddition with the
parent thioketone 2c. Spontaneous desulfurization of 17a
leads to the isolated product 18a. Consequently, higher dilu-
tion and increased temperature favor the formation of 18a.
The less reactive 2d reacted with 8a only at enhanced tem-
perature to give two products characterized as thiirane 17b
and vinylphosphonate 18b, but no formation of a 1,3-dithio-
Column chromatography was carried out using silica gel
(Merck 60, 0.063–0.200 mm). Thin layer chromatography
(TLC) was performed on Merck 5554 aluminum-backed
lane of type 11 was observed. Whereas the doublet for
]CH– of 18b was observed in the H NMR spectrum in
the typical region at ca. 6 ppm, the signal of the correspond-
SiO plates; products were visualized by UV light.
2
1
Toluene and THF were distilled from the blue solution of
sodium benzophenone ketyl.
1
ing H–C(2) of 17b was found at 2.74 ppm ( J ¼11.0 Hz).
HP
In boiling THF, the ratio of the two products was ca. 9:1 in
favor of 17b, whereas in boiling toluene, the proportion of
1
7
18
Thiobenzophenone (2a), 9H-fluorene-9-thione (2b),
9H-xanthene-9-thione (2c), and 9H-thioxanthene-9-thione
(2d) were prepared following the literature procedure.
1
7
18b increased (ratio 3:1). The separation of the products
was achieved by chromatography.
1
7
Prompted by the results obtained with 2c and 2d, the re-
actions of 8a with 2a and 2b (Scheme 2) were repeated in
boiling toluene. In the case of 2a, the corresponding vinyl-
phosphonate 18c was obtained as the sole product (Scheme
6). However, the reaction with 2b, despite higher dilution,
led to 1,3-dithiolane 11c (Scheme 3) exclusively, which con-
firmed the outstanding dipolarophilicity of this thioketone.
Methyl and ethyl diazomethylphosphonates (8) were pre-
pared by the Seyferth method.
1
9
4.2. Reaction of thiobenzophenone (2a) with diethyl and
dimethyl diazomethylphosphonate (8a) and (8b)
To a solution of 1 mmol of thiobenzophenone (2a) in dry
THF (1 mL) at ꢀ65 C, 1 mmol of diazomethylphosphonate
ꢁ
a or 8b, respectively, was added drop-wise. The mixture
8
was stirred and allowed to warm to room temperature
Ph
Ph
PO(OEt)2
-S
Ph
Ph
1
0a
ꢁ
PO(OEt)2
S
(decolorization of the mixture was observed at ꢀ15 C). The
solvent was evaporated and the solid residue was purified by
recrystallization.
1
7c
18c
Scheme 6.
An analogous experiment was carried out at room tempera-
ture leading to the same result.
3. Conclusion
4
.2.1. Diethyl (4,4,5,5-tetraphenyl-[1,3]dithiolan-2-yl)-
phosphonate (11a). Yield: 200 mg (74%). Colorless solid.
In conclusion, the described results show that diazomethyl-
phosphonates are attractive reagents for 1,3-dipolar cyclo-
additions, which in the case of C]S dipolarophiles exceed
the reactivity of the frequently used diazoacetates. The
presence of the phosphono group strongly influences the
reactivity of the resulting thiocarbonyl ylides. The synthetic
applications of these intermediates are limited by the avail-
ability of their precursors, and only ‘thiofluorenone’ 2b is
sufficiently reactive toward 8a to give the appropriate 2,5-
dihydro-1,3,4-thiadiazole derivative 9c. The dominant
tendency for cyclodimerization of 10c can be suppressed
only by addition of very reactive dipolarophiles to the reac-
tion mixture.
ꢁ
1
Mp 114–118 C (decomp.; hexane/AcOEt). H NMR:
2
d 1.41 (t, J¼7.0 Hz, 2CH ), 4.16 (d, J ¼6.6 Hz, CH),
3
HP
1
3
4.20–4.34 (m, 2CH O), 6.94–7.79 (m, 20arom. H).
2
C
3
1
NMR: d 16.4 (d, JCP¼5.9 Hz, 2CH ), 40.8 (d, JCP
¼
3
2
1
50.9 Hz, CHP), 63.6 (d, J ¼6.7 Hz, 2CH O), 79.6 (d,
CP
2
3
JCP¼7.0 Hz, 2C ), 126.1, 126.5, 126.6, 127.7, 127.9,
q
129.0, 131.1, 131.9 (20arom. CH), 142.4, 142.6 (4arom.
C ). IR (KBr, cm ): 3059m, 2981m, 1490s, 1443s, 1258s
ꢀ1
q
(P]O), 1043s and 1020s (P–O–C), 738m, 696s, 532m.
ESI-MS m/z (%): 569 (100, [M+Na] ). Anal. Calcd for
C H O PS (546.69): C 68.11, H 5.72; found: C 68.24,
2
+
3
1
31
3
H 5.46.
4.2.2. Dimethyl (4,4,5,5-tetraphenyl-[1,3]dithiolan-2-yl)-
phosphonate (11b). Yield: 250 mg (96%). Colorless solid.
Mp 84–86 C (decomp.; hexane/Et O). H NMR: d 3.90
2
4
. Experimental
ꢁ
1
3
2
4
.1. General
(d, JHP¼11 Hz, 2CH O), 4.20 (d, JHP¼6.9 Hz, CH),
3
1
3
6
.80–7.70 (m, 20arom. H).
C NMR: d 40.6 (d,
1
13
ꢁ
1
2
The H and C NMR spectra were recorded at ca. 21 C
with a Varian Gemini 200 BB VT ( H at 200.1 MHz,
JCP¼151.4 Hz, CHP), 54.3 (d, JCP¼6.7 Hz, 2CH O),
3
1
3
79.9 (d, J ¼7.3 Hz, 2C ), 126.7, 127.1, 127.3, 131.6,
CP
q
1
1
3
3
1
ꢀ1
C at 50.3 MHz) or a Bruker-AC-300 ( H at 300.1 MHz,
C at 75.5 MHz) spectrometer using CDCl as a solvent.
Chemical shifts (d) are reported in parts per million down-
field from internal TMS. The majority of signals were
assigned with the aid of ATP or DEPT spectra. IR spectra
132.3 (20arom. CH), 142.9 (4arom. C ). IR (KBr, cm ):
q
3056m, 2953m, 1490s, 1443s, 1262s (P]O), 1054s and
1032s (P–O–C), 739m, 700s, 532m. EIMS m/z (%): 518
(<1, M ), 288 (9), 211 (22), 210 (100), 198 (30), 197 (9),
3
+
178 (27), 165 (46), 121 (26).

7780
S. Lesniak et al. / Tetrahedron 62 (2006) 7776–7782
+
+
4.3. Reaction of diethyl diazomethylphosphonate (8a)
with 9H-fluorene-9-thione (2b)
m/z (%): 563 (37, [M+NH ] ), 562 (100), 546 (8, [M+1] ),
4
+
545 (21, M ), 366 (38), 349 (20), 317 (45), 210 (18), 200
(16), 199 (78), 197 (33). Anal. Calcd for C H O PS
31 29 3 2
To a solution of 1 mmol of 9H-fluorene-9-thione (2b) in dry
THF (1 mL), 1 mmol of diethyl diazomethylphosphonate
(544.68): C 68.36, H 5.37, S 11.77; found: C 67.88, H
5.30, S 12.22.
ꢁ
(
8a) was added drop-wise at ꢀ65 C. After 10 min stirring
ꢁ
at ꢀ65 C, decolorization of the mixture was observed.
For the synthesis of 12, the mixture was stirred and allowed
to warm to room temperature. For the synthesis of 11c, 11d,
4.3.4. Diisopropyl [2-(diethoxyphosphoryl)-5-methyl-
sulfanylspiro[9H-fluorene-9,4 -[1,3]dithiolane]-5-phos-
0
phonate (14). Yield: 260 mg (43%). Colorless solid. Mp
ꢁ
1
1
(
4, and 16, a respective dipolarophile 2a, 2b, 13 or 15
1 mmol) was added. The mixture was stirred and allowed
160–170 C (decomp.; hexane/dichloromethane).
H
NMR: d 0.74 (d, J¼6.2 Hz, CH ), 0.93 (d, J¼6.2 Hz,
3
to warm to room temperature. The solvent was removed in
vacuum and the solid residue purified by recrystallization.
CH ), 1.16 (d, J¼6.1 Hz, CH ), 1.30 (d, J¼6.1 Hz, CH ),
3
3
3
1.59 (t, J¼6.9 Hz, CH ), 1.60 (t, J¼6.9 Hz, CH ), 2.73 (s,
3
3
CH S), 4.43–4.68 (m, 2CH O, 2CHO), 5.40 (dd,
3
2
0
,9 -[9H]fluorene]-5 ,6 -diphosphonate (12). Yield:
2
4
4
3
1
.3.1. Tetraethyl dispiro[9H-fluorene-9,2 -[1,4]dithiane-
JHP¼4.6, J ¼1.1 Hz, CH), 7.36–7.79 (m, 6arom. H),
HP
0
60 mg (46%). Colorless solid. Mp 230–235 C (decomp.;
00
0
0
13
8.34–8.37 (m, 1arom. H), 8.68–871 (m, 1arom. H).
C
ꢁ
3
NMR: d 16.3 (d, JCP¼7.2 Hz, CH CH O), 16.5 (d,
3
2
1
3
3
3 2 CP 3
hexane/dichloromethane). H NMR: d 1.36 (t, J¼7.0 Hz,
JCP¼14.0 Hz, CH CH O), 22.0 (d, J ¼6.4 Hz, CH S),
1
3 2 CP
2
4
(
1
(
6
1
1
1
7
3
CH ), 1.37 (t, J¼7.0 Hz, 2CH ), 4.16–4.36 (m, 4CH O),
23.0, 23.5, 23.6, 23.9 (2(CH ) CH), 42.7 (dd, J ¼150.0,
3
3
2
2
3
3
2
.84 (dd, J ¼24.9 Hz, J ¼12.6 Hz, 2CH), 6.16–6.19
JCP¼11.0 Hz, CHP), 63.6 (d, J ¼6.9 Hz, CH O), 64.4
HP
HP
CP
2
2
2
m, 2arom. H), 6.63–6.69 (m, 2arom. H), 7.01–7.64 (m,
0arom. H), 9.05–9.10 (m, 2arom. H). C NMR: d 16.1
(d,
J
¼6.6 Hz, CH O), 71.0 (d,
J
CP
¼8.3 Hz,
q
CP
2
1
3
2
(CH ) CH), 73.3 (d, J ¼7.9 Hz, (CH ) CH), (2C not
3
2
CP
3 2
1
s, 4CH ), 38.0 (d, J ¼133.1 Hz, 2CHP), 57.0 (2C ),
found), 118.4, 119.3, 125.9, 126.6, 128.5, 129.1, 129.2,
130.7 (8arom. CH), 139.2, 140.3, 142.6, 149.4 (4arom.
C ). IR (KBr, cm ): 3058w, 2979m, 2925w, 1448m,
3
CP
q
2
3.1 (d, JCP¼58.6 Hz, 4CH O), 119.1, 120.1, 125.1,
2
ꢀ
1
26.4, 126.7, 127.7, 128.4, 128.6 (16arom. CH), 139.8,
40.5, 142.2, 148.3 (8arom. C ). IR (KBr, cm ): 2983m,
q
ꢀ1
1386m, 1256s, 1244s (P]O), 1046s, 1010vs and 985vs
(P–O–C), 743vs, 534m. CIMS (NH ) m/z (%): 604 (32,
q
630w, 1446m, 1249s (P]O), 1023vs (P–O–C), 976s,
42s, 553m. CIMS (NH ) m/z (%): 693 (100, [M+1] ),
29 (21), 318 (45), 197 (17). Anal. Calcd for
3
+
+
+
[M+1] ), 603 (100, M ), 389 (28), 375 (11), 202 (12), 200
(16).
3
C H O P S (692.77): C 62.42, H 5.53, S 9.26; found:
6 38 6 2 2
C 62.10, H 5.50, S 9.22.
3
0
thiolane]-5-phosphonate (16). Yield: 240 mg (51%).
Pale-yellow solid. Mp 159–162 C (decomp.; Et O). H
2
4.3.5. Diethyl 3,3,4,4-tetracyano-spiro[9H-fluorene-9,2 -
0
,9 -[9H]fluorene]-2 -phosphonate (11c). Yield: 400 mg
74%). Colorless solid. Mp 242–252 C (decomp.; hexane/
ꢁ
NMR: d 1.40–1.47 (m, 2CH ), 4.31–4.44 (m, 2CH O),
1
4
5
(
.3.2. Diethyl dispiro[9H-fluorene-9,4 -[1,3]dithiolan-
0
00
0
3
2
ꢁ
2
4.70 (d, J ¼16.3 Hz, CH), 7.18–7.77 (m, 7arom. H),
HP
1
13
3
dichloromethane). H NMR: d 1.41 (t, J¼7.0 Hz, 2CH ),
8.15–8.17 (m, 1arom. H). C NMR: d 16.2 (d, J ¼5.1 Hz,
3
CP
2
3
3 CP 3 CP
1
4
7
.28–4.38 (m, 2CH O), 5.52 (d, J ¼6.6 Hz, CH), 7.09–
CH ), 16.2 (d, J ¼4.6 Hz, CH ), 49.5 (d, J ¼147.3 Hz,
2
HP
1
3
3
2
q CP 2
.64 (m, 20arom. H). C NMR: d 16.4 (d, J ¼5.8 Hz,
CHP), 52.1, 60.0 (2C ), 65.4 (d, J ¼6.9 Hz, CH O), 65.8
CP 2
CP
1
2
2
CH3), 43.6 (d, JCP¼152.4 Hz, CHP), 63.9 (d,
(d, J ¼6.9 Hz, CH O), 107.5, 109.2, 109.4, 109.5 (4CN),
2
3
JCP¼6.8 Hz, 2CH O), 75.0 (d, J ¼7.0 Hz, 2C ), 119.0,
120.7, 120.8, 126.6, 128.2, 128.3, 128.7, 131.5, 131.8
(8arom. C), 139.8, 141.2, 142.7 (4arom. C ). IR (KBr,
2
CP
q
1
1
2
19.5, 126.1, 126.7, 128.6, 128.7 (20arom. CH), 127.7,
40.1 (4arom. C ). IR (KBr, cm ): 3055m, 2981m,
905m, 1476m, 1446s, 1259vs (P]O), 1047vs and 1020vs
q
ꢀ1
ꢀ1
cm ): 3064w, 2987m, 2920m, 2255w, 1451m, 1264s
(P]O), 1043vs and 1017vs (P–O–C), 752s, 744s, 548m.
CIMS (NH ) m/z (%): 492 (100, [M+NH ] ), 292 (40),
3
q
+
(
(
P–O–C), 964s, 741vs, 650m, 533m. CIMS (NH ) m/z
3
%): 562 (15), 561 (37), 560 (100, [M+NH ] ), 543 (15),
4
4
+
264 (27). Anal. Calcd for C H N O PS (474.48): C
31 19 4 3 2
349 (13), 348 (17), 329 (21), 202 (28), 200 (15), 197 (27).
Anal. Calcd for C H O PS (542.66): C 68.61, H 5.02,
S 11.82; found: C 68.50, H 4.95, S 12.33.
60.75, H 4.04, N 11.85, S 6.76; found: C 60.55, H 4.04, N
11.64, S 6.61.
3
1
27
3
2
4.4. Reaction of diethyl diazomethylphosphonate (8a)
with 9H-xanthene-9-thione (2c) and 9H-thioxanthene-
9-thione (2d)
0
1,3]dithiolane]-2-phosphonate (11d). Yield: 200 mg
37%). Colorless solid. Mp 172–178 C (decomp.; hexane/
0
0
4
[
(
.3.3. Diethyl 5 ,5 -diphenylspiro[9H-fluorene-9,4 -
ꢁ
1
Et O). H NMR: d 1.42 (t, J¼7.0 Hz, 2CH ), 4.29–4.38
To a solution of 1 mmol of 9H-xanthene-9-thione (2c) in dry
THF (1 mL), 1 mmol of diethyl diazomethylphosphonate
(8a) was added drop-wise at room temperature. After 24 h
stirring, decolorization of the mixture was observed. The
solvent was removed under vacuum and compound 11e
was separated and purified by recrystallization. The same
reaction in boiling THF gave products 11e and 18a in
a 2:3 ratio, whereas in boiling toluene the formation of
only 18a was observed. The reaction with 2d was carried
out in boiling toluene. Two products were separated chro-
matographically on silica gel (hexane/AcOEt).
2
3
2
(
m, 2CH O), 5.01 (d, J ¼6.7 Hz, CH), 5.65–5.67 (m,
2
HP
1
4
4
arom. H), 6.73–7.36 (m, 13arom. H), 7.73–7.80 (m,
arom. H). C NMR: d 16.5 (d, J ¼6.0 Hz, 2CH ),
1
3
3
CP
3
1
2
2.1 (d, JCP¼149.7 Hz, CHP), 63.8 (d,
J
¼6.9 Hz,
CP
2
CH O), 63.9 (d, J ¼6.7 Hz, CH O), 75.9, 78.0 (2C ),
2
CP
2
q
1
1
1
2
1
20.1, 120.5, 124.7, 126.5, 126.7, 127.1, 127.5, 127.7,
28.1, 128.2, 129.0 (18arom. CH), 132.0, 138.3, 140.4,
42.8, 145.1, 148.0 (6arom. C ). IR (KBr, cm ): 3055m,
ꢀ1
q
981m, 2905m, 1475m, 1444s, 1257s (P]O), 1046vs and
020vs (P–O–C), 975s, 745vs, 699s, 536m. CIMS (NH3)

S. Lesniak et al. / Tetrahedron 62 (2006) 7776–7782
7781
0
,9 -[9H]xanthene]-2 -phosphonate (11e). Yield: 180 mg
63%). Colorless solid. Mp 156–158 C (decomp.; hexane/
4
5
(
.4.1. Diethyl dispiro[9H-xanthene-9,4 -[1,3]dithiolane-
0
CHP), 125.8, 125.9, 126.1, 126.3, 127.1, 128.4, 128.9,
130.2 (8arom. CH), 131.9 (d, J ¼5.6 Hz, C ), 136.0,
00
0
2
CP
q
ꢀ1
ꢁ
136.3, 151.9, 152.0 (4arom. C ). IR (KBr, cm ): 3053w,
q
1
dichloromethane). H NMR: d 1.48 (t, J¼7.0 Hz, 2CH ),
2980w, 2934w, 2903w, 1586m, 1559w, 1464w, 1438m,
1241s (P]O), 1160w, 1049s and 1035s (P–O–C), 960s,
3
2
4
7
.37–4.47 (m, 2CH O), 5.53 (d, J ¼6.1 Hz, CH), 6.67–
2
HP
1
3
.52 (m, 14arom. H), 8.04–8.07 (m, 2arom. H). C NMR:
934w, 843m, 778m, 764m, 548m. CIMS (NH ) m/z (%):
3
3
1
+
d 16.5 (d, J ¼5.8 Hz, 2CH ), 43.9 (d, J ¼153.3 Hz,
364 (10, [M+NH ] ), 363 (46), 348 (13), 347 (21), 346
4
CP
2
3
CP
3
+
CHP), 63.9 (d, J ¼6.9 Hz, 2CH O), 74.5 (d, J ¼7.1 Hz,
(100, M ). Anal. Calcd for C H O PS (346.39): C 62.42,
18 19 3
CP
2
CP
2
1
1
1
5
C ), 115.5, 116.0, 121.9, 128.7, 128.9, 130.3 (16arom. CH),
q
H 5.53, S 9.26; found: C 62.35, H 5.38, S 9.32.
ꢀ1
51.3, 151.8 (4arom. C ). IR (KBr, cm ): 2983w, 2915w,
q
597m, 1474s, 1443s, 1308m, 1281m, 1246s (P]O),
044s and 1017vs (P–O–C), 749s, 536m. ESI-MS m/z (%):
97 ([M+Na] ). Anal. Calcd for C H O PS (574.65):
4.5. X-ray crystal-structure determination of 11a and 12
+
All measurements were performed on a Nonius KappaCCD
area-diffractometer using graphite-monochromated Mo
3
1
27
5
2
2
0
C 64.53, H 4.68, S 10.95; found: C 64.79, H 4.74, S 11.16.
˚
Ka radiation (l 0.71073 A) and an Oxford Cryosystems Cryo-
stream 700 cooler. The data collection and refinement para-
meters are given below and views of the molecules are
shown in Figures 1 and 2. Data reduction was performed
4.4.2. Diethyl (9H-xanthen-9-ylidene)methylphospho-
nate (18a). Yield: 200 mg (61%). Colorless solid. Mp 72–
2
1
ꢁ
1
7
3
7
3 C (hexane). H NMR: d 1.22 (t, J¼7.0 Hz, 2CH ),
3
2
2
2
with HKL Denzo and Scalepack. The intensities were cor-
rected for Lorentz and polarization effects, and absorption
.98–4.12 (m, 2CH O), 5.92 (d, J ¼8.9 Hz, CH), 7.16–
2
HP
.28 (m, 4arom. H), 7.38–7.47 (m, 2arom. H), 7.71–7.74
2
3
1
3
corrections based on the multi-scan method were applied.
Equivalent reflections were merged. The structures were
solved by direct methods using SIR92 in the case of 11a
(
m, 1arom. H), 8.52–8.55 (m, 1arom. H). C NMR: d 16.2
3
2
(
d, J ¼6.6 Hz, 2CH ), 61.8 (d, J ¼6.0 Hz, 2CH O),
CP
3
CP
2
2
4
1
1
1
1
05.3 (d, J ¼198.2 Hz, CHP), 116.6, 117.2 (2arom. C),
CP
2
5
2
and SHELXS97 in the case of 12, which revealed the posi-
tions of all non-H-atoms. In the case of 11a, one ethyl group is
disordered over two conformations. Two sets of overlapping
positions were defined for the atoms of the disordered ethyl
group and the site occupation factor of the major conformation
of the group refined to 0.818(6). In the case of 12, the terminal
methyl group of one ethoxy moiety is disordered over two
conformations. Two positions were defined for the atoms of
the disordered methyl group and the site occupation factor
of the major conformation refined to 0.51(3). For both struc-
tures, similarity restraints were applied to the chemically
equivalent bond lengths and angles involving all disordered
C-atoms, while neighboring atoms within and between each
conformation of the disordered ethyl groups were restrained
to have similar atomic displacement parameters. The non-
H-atoms were refined anisotropically. All of the H-atoms
were placed in geometrically calculated positions and refined
using a riding model where each H-atom was assigned a fixed
isotropic displacement parameter with a value equal to 1.2Ueq
of its parent C-atom (1.5Ueq for the methyl groups). The
19.8 (d, J ¼7.1 Hz, C ), 123.2, 124.1, 124.2, 129.6,
CP
q
30.8, 131.5 (8arom. CH), 143.8, 143.9, 151.3, 152.0
ꢀ
4arom. C ). IR (KBr, cm ): 3058w, 3033w, 2985m,
q
1
(
2
1
900w, 1604s, 1564m, 1477m, 1456s, 1391w, 1361w,
320m, 1284m, 1245s 1236s (P]O), 1047s and 1035s
(
P–O–C), 966s, 788s, 770s, 547m. CIMS (NH ) m/z (%):
3
48 (7, [M+NH ] ), 333 (8), 332 (20), 331 (100, [M+1] ).
4
+
+
3
Anal. Calcd for C H O P (330.32): C 65.45, H 5.80;
1
8 19 4
found: C 65.30, H 5.92.
0
.4.3. Spiro[thiirane-2,9 -[9H]thioxanthene]-3-phospho-
nate (17b). Yield: 190 mg (50%). Eluted with hexane/
4
AcOEt 1:1 and recrystallized from hexane. Pale-yellow
ꢁ
1
solid. Mp 69–72 C (hexane). H NMR: d 1.16 (t,
2
J¼7.1 Hz, CH ), 1.18 (t, J¼7.1 Hz, CH ), 2.74 (d, J
¼
3
3
HP
1
4
1.0 Hz, CH), 3.76–3.92 (m, 2CH O), 7.19–7.28 (m,
2
arom. H), 7.45–7.49 (m, 2arom. H), 7.60–7.63 (m,
arom. H), 7.68–7.71 (m, 1arom. H). C NMR: d 16.3 (d,
1
3
1
3
1
JCP¼4.2 Hz, 2CH ), 40.7 (d, J ¼184.1 Hz, CHP), 55.1
3
CP
2
2
(
CH O), 126.1, 126.2, 126.6, 126.8, 127.5, 127.7, 130.3
C ), 62.4 (d, J ¼6.5 Hz, CH O), 63.0 (d, J ¼6.7 Hz,
2
q
CP
2
CP
refinement of the structures was carried out on F using full-
matrix least-squares procedures, which minimized the func-
2
P
(
(
8arom. CH), 133.0, 136.1, 136.4, 137.0 (4arom. C ). IR
q
KBr, cm ): 3057w, 2982m, 2929w, 2904w, 1457m,
2
2 2
tion
wðF ꢀ F Þ . A correction for secondary extinction
ꢀ1
o
c
was applied in the case of 12. In 11a and 12, three and one
reflections, respectively, whose intensities were considered
to be extreme outliers, were omitted from the final refinement.
Neutral atom scattering factors for non-H-atoms were taken
from Ref. 26, and the scattering factors for H-atoms were
taken from Ref. 27. Anomalous dispersion effects were
1
9
3
441m, 1263s, 1243m (P]O), 1045s and 1027s (P–O–C),
71s, 787m, 742s, 545m. CIMS (NH ) m/z (%): 380 (5),
3
+
79 (10), 378 (44, M ), 365 (10), 363 (46), 347 (21), 346
+
(100, [MꢀS] ), 332 (20), 331 (13). Anal. Calcd for
C H O PS (378.45): C 57.13, H 5.06, S 16.94; found:
1
8
19
3
2
C 57.16, H 4.99, S 16.83.
28
0
00
included in Fc; the values for f and f were those of
Ref. 29. The values of the mass attenuation coefficients are
those of Ref. 30. All calculations were performed using the
4.4.4. Diethyl (9H-thioxanthen-9-ylidene)methylphos-
phonate (18b). Yield: 100 mg (29%). Eluted with AcOEt
3
1
SHELXL97 program.
and recrystallized from hexane. Colorless solid. Mp 74–
ꢁ
1
7
5 C (hexane). H NMR: d 1.11 (t, J¼7.1 Hz, CH ), 1.12
Crystal data for 11a: C H O PS , M¼546.68, colorless,
3
31 31
3
2
(
t, J¼7.1 Hz, CH ), 3.86–3.97 (m, 2CH O), 5.92 (d,
prism, crystal dimensions 0.15ꢂ0.25ꢂ0.32 mm, triclinic,
space group P1, Z¼2, reflections for cell determination
3
2
2
J
m, 2arom. H), 7.63–7.66 (m, 1arom. H), 8.19–8.22 (m,
¼12.5 Hz, CH), 7.26–7.36 (m, 4arom. H), 7.43–7.49
HP
ꢁ
(
32 546, 2q range for cell determination 4–50 , a¼
1
3
3
˚
˚
˚
1
arom. H). C NMR: d 16.0 (d, J ¼6.8 Hz, 2CH ),
8.4060(3) A, b¼9.8163(4) A, c¼17.4649(7) A, a¼
CP
3
2
1
ꢁ ꢁ ꢁ
˚
3
6
1.8 (d, J ¼6.1 Hz, 2CH O), 115.4 (d, J ¼191.6 Hz,
87.447(3) , b¼76.876(2) , g¼77.811(2) , V¼1371.84(9) A ,
CP
2
CP

7782
S. Lesniak et al. / Tetrahedron 62 (2006) 7776–7782
ꢀ
3
ꢀ1
T¼160 K, D ¼1.323 g cm , m(Mo Ka)¼0.284 mm
,
8. K €a gi, M.; Mloston, G.; Heimgartner, H. Pol. J. Chem. 1998, 72,
678–687.
9. K €a gi, M.; Mloston, G.; Linden, A.; Heimgartner, H. Helv.
Chim. Acta 1994, 77, 1299–1312.
10. Urbaniak, K.; Mloston, G.; Gulea, M.; Masson, S.;
Heimgartner, H. Pol. J. Chem. 2005, 79, 1483–1494.
11. Mloston, G.; Urbaniak, K.; Gulea, M.; Masson, S.; Linden, A.;
Heimgartner, H. Helv. Chim. Acta 2005, 88, 2582–2592.
12. (a) Huisgen, R.; Langhals, E. Tetrahedron Lett. 1989, 30,
5369–5372; (b) Huisgen, R.; Li, X.; Giera, H.; Langhals, E.
Helv. Chim. Acta 2001, 84, 981–999.
X
ꢁ
scan type u, 2q(
¼50 , transmission factors (min; max)
max)
0
.757; 0.966, total reflections measured 17 711, symmetry
independent reflections 4832, reflections with I>2s(I)
935, reflections used in refinement 4829, parameters
3
refined 356; restraints 38, R(F) [I>2s(I) reflections]¼
2
2
2
o
0
.0407, wR(F ) [all data]¼0.1055 (w¼½s ðF Þþ
2
ꢀ1
2
o
2
c
ð0:0471PÞ þ0:7354Pꢃ , where P¼ðF þ 2F Þ=3), good-
ness of fit 1.064, final D /s¼0.002, Dr (max; min)¼
max
ꢀ3
0
.34; ꢀ0.50 e A˚
.
Crystal data for 12: C H O P S , M¼692.76, colorless,
13. Johnson, C. K. ORTEP II, Report ORNL-5138; Oak Ridge
National Laboratory: Oak Ridge, Tennessee, 1976.
14. Huisgen, R.; Mloston, G.; Polborn, K.; Sustmann, R. Chem.—
Eur. J. 2003, 9, 2256–2263.
15. Urbaniak, K.; Mloston, G.; Gulea, M.; Masson, S.; Linden, A.;
Heimgartner, H. Eur. J. Org. Chem. 2005, 1604–1612.
16. According to the NMR spectra, 14 has been formed as a single
stereoisomer but its relative configuration has not been deter-
mined.
17. Pedersen, B. S.; Scheibye, S.; Nilsson, N. H.; Lawesson, S.-O.
Bull. Soc. Chim. Belg. 1978, 87, 223–228.
18. Scheibye, N. H.; Shabana, R.; Lawesson, S.-O.; Romming, C.
Tetrahedron 1982, 38, 993–1001.
3
6 38 6 2 2
prism, crystal dimensions 0.10ꢂ0.22ꢂ0.22 mm, mono-
clinic, space group P2 /n, Z¼4, reflections for cell determi-
1
ꢁ
˚
nation 63 677, 2q range for cell determination 4–60 ,
˚
˚
3
a¼12.1758(1) A,
b¼13.0645(1) A,
c¼21.1455(2) A,
ꢁ
˚
b¼93.5396(7) , V¼3357.21(5) A , T¼160 K, D ¼
X
ꢀ
3
ꢀ1
1
.370 g cm , m(Mo Ka)¼0.300 mm , scan type f and
ꢁ
.973, total reflections measured 89 162, symmetry in-
u, 2q(max)¼60 , transmission factors (min; max) 0.868;
0
dependent reflections 9809, reflections with I>2s(I) 7639,
reflections used in refinement 9808, parameters refined
4
31; restraints 7, R(F) [I>2s(I) reflections]¼0.0443,
2
2
2
2
wR(F ) [all data]¼0.1198 (w¼½s ðF Þþð0:0536PÞ þ
o
ꢀ
1
2
o
2
c
1
secondary extinction coefficient 0.0021(6), final D
s¼0.001, Dr (max; min)¼0.36; ꢀ0.53 e A
:7904Pꢃ , where P¼ðF þ2F Þ=3), goodness of fit 1.062,
19. Seyferth, D.; Marmor, R. S.; Hilbert, P. J. Org. Chem. 1971, 36,
1379–1386.
20. Hooft, R. KappaCCD Collect Software; Nonius BV: Delft,
The Netherlands, 1999.
/
max
˚
ꢀ3
.
2
1. CCDC-604266–604267 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free
of charge from the Cambridge Crystallographic Data Centre,
via www.ccdc.cam.ac.uk/data_request/cif.
Acknowledgements
This project was supported by the grant No. 505/681/2004
from the University of q o´ d z´ . We acknowledge the financial
support by the Polish State Committee for Scientific
Research (Grant No. 4 T09A 046 25) and F. Hoffmann-
La Roche AG, Basel.
22. Otwinowski, Z.; Minor, W. Macromolecular Crystallography,
Part A; Carter, C. W., Jr., Sweet, R. M., Eds.; Methods in
Enzymology; Academic: New York, NY, 1997; Vol. 276,
pp 307–326.
2
2
3. Blessing, R. H. Acta Crystallogr., Sect. A 1995, 51, 33–38.
4. Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.;
Burla, M. C.; Polidori, G.; Camalli, M. SIR92, J. Appl.
Crystallogr. 1994, 27, 435.
References and notes
1
. (a) Maas, G. Chem. Soc. Rev. 2004, 33, 183–190 (and refer-
ences cited therein); (b) Kubo, T.; Sakaguchi, S.; Ishii, Y.
Chem. Commun. 2000, 625–626; (c) Galliford, Ch. V.;
Beenen, M. A.; Nguyen, S. T.; Scheidt, K. A. Org. Lett.
25. Sheldrick. SHELXS97, Program for the Solution of Crystal
Structures; University of G €o ttingen: Germany, 1997.
26. Maslen, E. N.; Fox, A. G.; O’Keefe, M. A. International Tables
for Crystallography; Wilson, A. J. C., Ed.; Kluwer Academic:
Dordrecht, 1992; Vol. C, pp 477–486; Table 6.1.1.1.
27. Stewart, R. F.; Davidson, E. R.; Simpson, W. T. J. Chem. Phys.
1965, 42, 3175–3187.
2
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