Unexpected thermal reactivity of phosphirano-[1,2]thiaphosphole P-W(CO)5 complexes

Article abstract of DOI:10.1002/ejoc.200900002

Spiro[fluorene-9,6′-[2]thia[1]phosphabicyclo[3.1.0]hex[3]- enes] 7a-c have been obtained in one step from 3,5-diaryl- 1,2-thiaphospholes and 9-diazofluorene or its 2,7-dibromo derivative. The bicyclic phosphiranes are stable against water and resist attem

Full text of DOI:10.1002/ejoc.200900002

FULL PAPER
DOI: 10.1002/ejoc.200900002
Unexpected Thermal Reactivity of Phosphirano-[1,2]thiaphosphole P–W(CO)5
Complexes
Stefan Maurer,[a] Tamaki Jikyo,[a][‡] and Gerhard Maas*[a]
Keywords: Cycloaddition / Diazo compounds / Spiro compounds / Phosphorus heterocycles / Sulfur heterocycles
Spiro[fluorene-9,6Ј-[2]thia[1]phosphabicyclo[3.1.0]hex[3]-
enes] 7a–c have been obtained in one step from 3,5-diaryl-
1,2-thiaphospholes and 9-diazofluorene or its 2,7-dibromo
derivative. The bicyclic phosphiranes are stable against
water and resist attempts at sulfuration or selenation of the
phosphorus atom. However, cleavage of the P–C ring fusion
9,2Ј-[2H]phosphole] 13, which is reconverted into 11a upon
treatment with sulfur. Bicyclic 1,3,2-dithiaphospholanes 12a–
c are formed as minor byproducts of the thermal isomeriza-
tion of phosphiranes 10. Compound 10a slowly rearranges in
solution to give 12a as the sole product. Compounds 12 may
result from a formal [3+2] cycloaddition reaction of an α,β-
with hydrogen chloride followed by hydrolysis led to the mo- unsaturated thione, formed by partial decomposition of 10,
nocyclic 2-(9H-fluoren-9-yl)-2,3-dihydro-1,2-thiaphosphole
2-oxides 8a–c. Phosphiranes 7a–c also react to form the hexa-
carbonyltungsten-(P–W) complexes 10a–c readily and in high
yields. These complexes rearrange in toluene solution at 50–
80 °C to form the spiro[fluorene-9,2Ј-[1]phospha[6]thiabicy-
clo[3.1.0]hex-3-ene]-W(CO)5-(P–W) complexes 11a–c, which
are the first representatives of ring-fused thiaphosphiranes.
Compound 11a is readily desulfurated with tributylphos-
phane to form the highly oxygen-sensitive spiro[fluorene-
with a dipolar valence isomer of 10 or 11, featuring a
W(CO)5-complexed thiocarbonyl-phospha-ylide dipole
(R2C=S+–P–R). W(CO)5 complexation is not a prerequisite for
the cycloaddition reaction: the uncomplexed phosphirano-
thiaphosphole 7a reacts with thiobenzophenone in the same
way to form the bicyclic 1,3,2-dithiaphospholane 18 in high
yield.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
Introduction
Bicyclic [a]-fused phosphiranes appear not to have been
used so far as ligands in transition-metal-catalyzed reac-
tions, although the existence of a variety of metal carbonyl
complexes[1,9] indicates the coordinating ability of the
phosphorus atom in this structural environment. Further-
more, the chemistry of this particular type of phosphirane
is not yet well developed. A versatile approach to [a]-fused
phosphiranes is provided by the cyclopropanation of the
P=C bond of heterophospholes with diazo compounds
Phosphiranes are strained three-membered heterocycles,
the chemistry of which has been well investigated.[1] They
can also be looked at as cyclic phosphanes, and therefore
they have attracted attention as potential ligands in catalyti-
cally active transition-metal complexes.[2] Owing to the
strong pyramidalization at the phosphorus, the ligand prop-
erties of phosphiranes are expected to be different to those
of common acyclic phosphanes because a rather weak σ-
donor character is paired with a significant π-accepting
ability.[3–5] However, many phosphiranes appear to be less
suited as ligands because they are chemically quite reactive.
This problem is solved by the introduction of bulky substit-
through
a
[3+2] cycloaddition/ring-contraction se-
quence.[10] As 3,5-diaryl-1,2-thiaphospholes are readily
available[11] and the P=C bond of 1,2-thiaphospholes is an
excellent cycloaddition partner,[12–14] we followed this
uents to reduce the reactivity of the phosphorus atom[3] or route to synthesize a 6,6-diphenyl-2-thia-1-phosphabi-
by the incorporation of the latter into a rigid polycyclic ring cyclo[3.1.0]hex-3-ene using diazodiphenylmethane as the
system to suppress the decomposition by a [2+1] cyclorever- cyclopropanation reagent.[15] We found that the thermal
sion. By taking the latter approach, Grützmacher and co-
workers have designed the BABAR-Phos class of phosphir-
anes,[4–7] which were found to form fairly stable RhI and
Pt0 complexes that could be used as hydrosilylation[4] and
hydroboration[8] catalysts.
stabilities of both the phosphirane and its W(CO)5 and
Fe(CO)4 complexes are only moderate, and that the effect
of elevated temperatures is different for the free phosphir-
ane and its metal complexes.
In continuation of these studies, we have synthesized spi-
ro[fluorene-9,6Ј-[2]thia[1]phosphabicyclo[3.1.0]hex[3]enes]
and their P–W(CO)5 complexes and have found that the
thermally induced reactivities of the latter are surprisingly
different from the 6,6-diphenyl derivative mentioned above.
The results are reported in this paper.
[a] Institute for Organic Chemistry I, University of Ulm,
Albert-Einstein-Allee 11, 89081 Ulm, Germany
Fax: +49-731-5022803
E-mail: gerhard.maas@uni-ulm.de
[‡] Present address: Institute of Preventive and Medicinal Dietetics,
Nakamura Gakuen University, Fukuoka 814-0198, Japan
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Scheme 1. Formation of thieno[3,2-a]isophosphindole derivatives 3.
Results and Discussion
In our earlier communication,[15] we reported that the
3,5,6,6-tetraphenyl-substituted phosphirano-thiaphosphole
1a smoothly forms a pentacarbonyltungsten-(P–W) com-
plex 2a, which undergoes a skeletal rearrangement to the
W(CO)5-complexed dihydroisophosphindole 3a at elevated
temperature (Scheme 1). We have now found that the
W(CO)5 complex of the analogous 3-(4-anisyl)-substituted
bicyclic phosphirane 1b can be observed in solution (δP =
–57.5 ppm) but cannot be isolated in pure form because it
is readily transformed into dihydroisophosphindole 3b un-
der the conditions of its formation from 1b (25 °C, 24 h).
The 2-phenylphosphirane Ǟ dihydroisophosphindole ring-
expansion pathway is likely to include the strongly reso-
nance-stabilized 1,3-diradical 4 resulting from homolytic
cleavage of the C–C bond of the phosphirane ring.
Scheme 2. Synthesis of spiro[fluorene-9,6Ј-[2]thia[1]phosphabicy-
clo[3.1.0]hex[3]enes] 7a–c.
The structure of 7a was ascertained by X-ray structure
analysis (Figure 1). The P–C bonds of the phosphirane ring
We speculated that replacement of the Ph2C· unit in di- (1.904, 1.889 Å) are exceptionally long compared with the
radical 4 by a fluoren-9-yl radical might not allow the radi- hitherto documented range of 1.78–1.89 Å.[1b] On the other
cal 1,5-cyclization to take place. Therefore, our attention hand, the C–C bond length in the three-membered ring
was drawn to spiro[fluorene-9,6Ј-[2]thia[1]phosphabicy- (1.540 Å) is in the normal range. The strong pyramidali-
clo[3.1.0]hex[3]enes] 7. 1,2-Thiaphospholes 5a,b were found zation of the phosphorus atom is evident from the value of
to react with 9-diazofluorene (6a) and its 2,7-dibromo de- the sum of the bond angles (247.8°).
rivative 6b to give the phosphirano-[1,2]thiaphospholes 7a–
In the solid state, phosphirano-thiaphospholes 7 are re-
c in high yields (Scheme 2). The reaction is likely to occur markably stable. From a suspension in water, compound 7a
by a [3+2] cycloaddition reaction followed by N2 extrusion could be recovered unaltered after several days. All attempts
from the resulting pyrazoline and ring contraction.[10a] The to sulfurize (S8, NEt3) or selenize (grey or red Se, NEt3) the
progress of the reaction could easily be monitored by phosphorus atom failed. On the other hand, phosphiranes
31P NMR spectroscopy: δP(5a) = 204.2 ppm, δP(7a) = 7a–c turned out to be acid-labile. The products from treat-
–51.7 ppm. The loss of aromaticity of the heterophosphole ment with a water-containing ethereal HCl solution could
was indicated by the upfield shift of the signal of the ring be identified as 2-(fluoren-9-yl)-3H-1,2-thiaphosphole 2-ox-
proton 4-H: δH(5a) = 8.20 ppm, δH(7a) = 6.42 ppm. An ides 8a–c (Scheme 3) by their spectroscopic (e.g., δP = 78.3–
interesting detail in the 1H NMR spectra (400 MHz) of 79.2 ppm) and analytical data and were isolated in 60–76%
compounds 7 is the absence of signals from the 5-phenyl at yields. Complete transformation of 7a into 8a was also ob-
25 °C. Clearly, steric hindrance by the fluorene ring reduces served when a CDCl3 solution of 7a was left in an NMR
the rotation rate of the phenyl ring and leads to signal co- tube for 12 h. A strong band in the IR spectra of 8 at
alescence; at 227 K the signals of five magnetically non- around 1200 cm–1 is in the range expected for the P=O val-
equivalent ring protons are observed.
ence vibration of phosphinic acid thioesters.[16] Examina-
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Spiro[fluorene-phosphirano-thiaphosphole] P-W(CO)5 Complexes
P=O bond as well as a cis relationship between 9Ј-H and
P=O.[17] The supposed structure was confirmed by an X-
ray structure analysis of 8a (Figure 2). It is evident that the
given configuration is the thermodynamically favored dia-
stereoisomer because steric interactions between the fluo-
rene ring system and the trans-positioned 3-Ph group are
minimized. The fast reactions of 7a–c were unexpected be-
cause the 6,6-diphenyl-substituted analogue 1a proved to be
inert against HCl/water over several days.
Figure 1. Molecular structure of 7a in the solid state. Thermal dis-
placement ellipsoids are drawn at the 50% probability level. Se-
lected bond lengths [Å] and angles [°]: P–C(3) 1.889(2), P–C(4)
1.904(2), C(3)–C(4) 1.540(2), P–S 2.1018(7); C(3)–P–C(4) 47.89(7),
C(3)–C(4)–P 65.53(9), C(4)–C(3)–P 66.57(10), C(3)–P–S 94.60(6),
C(4)–P–S 105.29(6).
Figure 2. Molecular structure of 3H-1,2-thiaphosphole 2-oxide 8a
in the solid state. Thermal displacement ellipsoids are drawn at the
30% probability level. Selected bond lengths [Å] and angles [°]: P–
O 1.466(3), P–C(3) 1.855(3), P–C(4) 1.822(3), S–P 2.094(1); O–P–
S 112.97(12), C(3)–P–S 97.77(11), C(4)–P–S 108.95(12), C(4)–P–
C(3) 106.23(16), C(23)–C(3)–P 109.7(2).
A mechanistic proposal for the formation of the 1,2-thia-
phosphole 2-oxides 8 is given in Scheme 4. The transforma-
tion is likely to begin with the addition of hydrogen chloride
across the internal P–C bond of the phosphirane moiety of
7, resulting in the formation of the P-chloro-3,4-dihydro-
Scheme 3. Acid hydrolysis of 7.
tion of the 2JP,H coupling constants of the protons adjacent 1,2-thiaphosphorine 9. An analogous reaction has been de-
to the phosphorus centre (3-H: JP,H = 6.3 Hz; 9Ј-H: JP,H
=
scribed for phosphirano-[1,2,3]diazaphospholes and the re-
25.5 Hz) suggested a trans relationship between 3-H and the sulting chlorophosphanes were quenched with methanol to
Scheme 4. Suggested mechanism for the formation of 3H-1,2-thiaphosphole 2-oxides 8a–c.
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S. Maurer, T. Jikyo, G. Maas
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give the corresponding methoxyphosphanes.[18] In our case, 2.3:1) were formed almost exclusively (isolated yield of 12a:
solvolysis of 9 by the water present in the ethereal HCl solu- 68%) with traces (about 2%) of 11a,b. In [D3]acetonitrile,
tion could generate a hydroxyphosphane; isomerization of the transformation of 10a was 2–3 times faster than in tolu-
this hydroxyphosphane to the phosphane oxide, as shown ene: after 24 h at 22 °C, a conversion of 22% (yield of 11a:
in Scheme 4, is then conceivable.
4%; 12a: 16%) was observed compared with 8.7% in tolu-
When exposed to [W(CO)5(thf)], the phosphiranes 7a–c ene solution (almost exclusive formation of 12a). As 10a is
were readily converted into the pentacarbonyltungsten only sparingly soluble in acetonitrile at room temperature,
complexes 10a–c in high yields (Scheme 5). The 31P NMR the higher ratio of 11a/12a compared with the situation in
signals of the complexes are shifted downfield relative to toluene solution may reflect the influence of concentration
the parent phosphiranes 7 [e.g., δP(10b) = –37.0 ppm; δP(7b) on the different kinetics of the formation of 11a and 12a
= –54.2 ppm] and show a JP,W coupling constant typical of (monomolecular vs. bimolecular, see the discussion on the
η1-W(CO)5 complexes (e.g., 10b: JP,W = 275.6 Hz). Other mechanism). In acetonitrile solution at 80 °C, on the other
NMR changes occurring after complexation are also char- hand, the dominating transformation of the bicyclic phos-
3
acteristic of phosphiranes (an increase in JP,H and a de- phiranes 10 is the decomplexation reaction which reconsti-
1
crease in JP,C in the phosphirane ring). Owing to the in- tutes the metal-free phosphiranes 7.
crease in steric hindrance after addition of the W(CO)5
fragment, the rotation of the phenyl group directly attached
to the phosphirane ring is hindered on the NMR timescale
even at ambient temperature. In contrast to the parent pho-
sphiranes 7 (see above), the signals of the individual 5-Ph
1
protons are observable in the H NMR spectra under stan-
dard conditions.
Scheme 5. Synthesis of the W(CO)5–phosphirane complexes
10a–c.
In solution, the bicyclic phosphiranes 7 as well as their
W(CO)5 complexes 10 undergo further thermal transforma-
tions, which proceed slowly even at room temperature and
with an appreciable rate at 50–80 °C. However, only the P-
complexed compounds react cleanly, whereas the free bicy-
clic phosphiranes produce an inseparable mixture of unde-
Scheme 6. Thermally induced transformation of phosphirano-thia-
phosphole–W(CO)5 complexes 10a–c. See Table 1 for conditions
and yields.
fined products, as indicated by a multitude of 31P NMR Table 1. Results of the thermal reactions of 10a–c in toluene solu-
tion.
signals. The products obtained differ significantly from the
tricyclic thieno[3,2-a]isophosphindole derivatives 3 ob-
served upon heating of the analogous 6,6-diphenyl-1,2-
phosphirano-thiaphosphole complexes 2 (see Scheme 1).[15]
For the spiro-connected complexes 10, heating at 80 °C in 10b
toluene led to the thiaphosphirane complexes 11 [δP = –6.4
(11a), –6.2 (11b), –6.9 (11c) ppm] in yields of up to 80%
(Scheme 6 and Table 1). Bicyclic dithiaphospholanes 12
were obtained as minor byproducts as a mixture of two
stereoisomers (e.g., 12a: δP = 54.3 and 53.1 ppm, 7:1 ratio;
repeated chromatographic purification shifted this ratio to
10:1). When a solution of 10a,b in [D1]chloroform or [D8]-
Conditions % Conversion % Yield of
δP(12)[a] [ppm]
11, 12
10a
80 °C, 48 h
80 °C, 3 h
50 °C, 24 h
80 °C, 8 h
50 °C, 72 h
100
100
79
88
44
80, 7
54.3, 53.1
53.6, 52.2
70, 0
61, 20[b]
70, 15[b,c]
24, 20[b,c]
10c
58.0, 53.2
[a] Two isomers, values refer to the major/minor isomer. [b] Yield
determined by 31P NMR spectroscopy. [c] Purification and separa-
tion not possible.
The structures of 11a and 12a were clarified by X-ray
1
toluene was allowed to stand at ambient temperature for structure analysis (Figure 3 and Figure 4). The H NMR
4 weeks, dithiaphospholanes 12a,b (ratio of isomers for 12a: spectra of 12a displayed two signals for the fluorenyl proton
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Spiro[fluorene-phosphirano-thiaphosphole] P-W(CO)5 Complexes
9-H with the same intensity ratio as observed in the 31P
NMR spectra [δH(9-H)
= 5.07 (major isomer) and
4.90 ppm]. The two isomers are either the E and Z isomers
of the exocyclic double bond or the two C-6 epimers. As
the signal(s) of the exocyclic olefinic proton appears amid
the many aromatic protons and therefore could not be ob-
served separately, neither of the two possibilities can be ex-
cluded.
Figure 4. Molecular structure of bicyclic 1,3,2-dithiaphospholane
12a in the solid state. Thermal displacement ellipsoids are drawn
at the 30% probability level. Hydrogen atoms have been omitted
for clarity. Selected bond lengths [Å] and angles [°]: S(1)–P 2.086(2),
S(1)–C(6) 1.856(5), S(2)–P 2.069(2), S(2)–C(7) 1.849(5), C(6)–C(7)
1.620(7), C(8)–C(9) 1.324(8), P–C(10) 1.892(6), P–W(1) 2.5244(14);
S(2)–P–S(1) 96.46(8), S(1)–C(6)–C(7) 107.5(3), S(2)–C(7)–C(6)
109.0(3), P–S(1)–C(6) 102.2(2), P–S(2)–C(7) 92.9(2), C(10)–P–W(1)
125.4(2).
Figure 3. Molecular structure of thiaphosphirane 11a in the solid
state. Thermal displacement ellipsoids are drawn at the 30% prob-
ability level. Selected bond lengths [Å] and angles [°]: P–C(1)
1.833(3), P–S 2.085(1), S–C(1) 1.883(4), P–C(4) 1.895(3), P–W
2.4457(9); P–C(1)–S 68.23(12), C(1)–P–S 57.01(11), C(1)–S–P
54.75(10), C(2)–C(3)–C(23) 123.6(3).
ported PPh3 was used for the desulfuration, incomplete
conversion was observed even after 24 hours. On the other
hand, phosphole 13 reacted immediately with an excess of
elemental sulfur and was reconverted quantitatively into
Heterocycles 11 are the first ring-fused thiaphosphiranes 11a.
and also the first 1,2λ3-thiaphosphirane complexes reported
The fate of 2H-phosphole 13 upon exposure to air can
so far. Only a few examples of monocyclic 1,2λ3- and 1,2λ5- be clarified. When a solution of freshly prepared 13 was in
thiaphosphiranes have been reported.[19] All the bond contact with air, it was consumed quantitatively within
lengths in the three-membered ring of 11a are shorter than 1 min (31P NMR control). Column chromatography al-
in 2-mesityl-3,3-diphenyl-1,2-thiaphosphirane,[19e] an effect lowed the separation of fluorenylidenepropanone 14 (80%
that is associated with the diminished electron density at yield) from tributylphosphane sulfide and a fraction, which
the phosphorus due to complexation.
according to the 31P chemical shifts, was a mixture of the
Similar to simple thiiranes,[20] 1,2-thiaphosphiranes known[23] tungsten complexes trans- and cis-[W(CO)4-
should be amenable to desulfuration by appropriate tertiary (PBu3)2] and [W(CO)5(PBu3)] (δP = –2.23, –9.25 and
phosphanes. This transformation has so far been successful –5.88 ppm, respectively). The mode of formation of 14 is
with 1,2λ5-phosphiranes,[19d,19e] and in one case also with not yet fully clear. Similarly to the behavior of phosphaalk-
1,2λ3-phosphiranes.[21] We found that 11a could be desul- enes,[24] however, it may be assumed that 13 initially reacts
furated with tributylphosphane within 1 min to furnish the with oxygen to undergo an oxidative cleavage via a 1,2,3-
W(CO)5-containing complex 13 quantitatively (Scheme 7). dioxaphosphetane. The details of the loss of the [P(=O)
Owing to its high sensitivity toward oxygen (see below), this W(CO)5] fragment from the ring-opened intermediate are
phosphole, which displays a 31P NMR resonance (δP
233.5 ppm) in the expected[22] range, could not
be separated from the byproducts. When polymer-sup- 12 from the phosphirano-thiaphosphole–W(CO)5 com-
=
unknown.
A mechanism for the formation of compounds 11 and
Scheme 7. Synthesis and reactions of 2H-phosphole 13.
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plexes 10 is proposed in Scheme 8. The conversion 10 Ǟ 11
At this point, it is appropriate to recall the thermal be-
at elevated temperature corresponds to a valence isomeriza- havior of the 6,6-diphenyl-substituted 2-thia-1-phospha-
tion, for which a stepwise pathway is proposed. A concerted bicyclo[3.1.0]hex-3-enes 1a,b and their W(CO)5 complexes
4e electrocyclic process would have to take a conrotatory 2.[15] The uncomplexed phosphirane 1a undergoes a ther-
course, which cannot be realized by the bicyclic structure mal fragmentation to yield a butadienyl sulfide (i.e., a tau-
of 10. A six-membered phosphorus heterocycle 15, which tomer of an alkenyl thione that is structurally analogous to
can be considered as a thiocarbonyl-phosphaylide dipole or 16 in Scheme 8), for which a phosphinidene cycloreversion,
the corresponding 1,3-diradical, could be generated by analogous to the one proposed above for the W(CO)5-com-
cleavage of the ring-connecting P–C bond and could form plexed phosphiranes 10, has been suggested. The W(CO)5
phospholo-thiaphosphirane 11 by 1,3-cyclization. The ob- complexes 2, on the other hand, undergo a skeletal re-
served rate acceleration for the isomerization of 10b (Ar = arrangement (see Scheme 1) beginning with a homolytic
4-anisyl) compared with 10a (Ar = Ph) is reasonable as the cleavage of the phosphirane C–C bond, which is in contrast
anisyl substituent can stabilize both a positive charge and to the suggested P–C bond cleavage of 10 at elevated tem-
a radical centre on the thiocarbonyl carbon atom of the perature. It would be interesting to know whether the dif-
intermediate 15. On the other hand, the formation of 12, ferent reaction pathways are related to the bond lengths in
which occurs slowly at room temperature, is likely to begin the phosphirane rings of 1, 2 and 10. However, all our ef-
with the cleavage of the phosphirane ring by a [2+1] cyclo- forts to obtain suitable crystals of 10a for structure determi-
reversion. This generates a tungsten-complexed phosphinid- nation failed and therefore comparison with 2a[15] was not
ene unit, R–S–P=W(CO)5, which after loss of the PW- possible.
(CO)5 fragment and hydrogen abstraction (from the sol-
Ylides of the type R2C=S+–P––R, as embedded in inter-
vent) yields the ene-thione 16. A formal [3+2] cycloaddition mediate 15, have not yet been described in the literature.
of the latter to 10, 11 or 15 provides the bicyclic 1,3,2-di- However, two related types of phosphaylides have been de-
thiaphospholane 12. The postulated cycloreversion step has scribed recently. Streubel and co-workers[25] proposed a car-
analogies in the chemistry of phosphiranes. Thus, it has bonyl phosphaylide [R2C=O+–P–(RЈ)–W(CO)5] as an inter-
been reported that Fe(CO)4-complexed bicyclic P-amino- mediate in the reaction of a (2H-azaphosphirene)pentacar-
phosphiranes (2-aza-1-phosphabicyclo[n.1.0]alkanes) un- bonyltungsten complex with 2 equiv. of an aldehyde fur-
dergo a slow [2+1] cycloreversion at room temperature and nishing a 1,4,2-dioxaphospholane. Lammertsma and co-
that the formed R–P=Fe(CO)4 intermediates can be workers[26] discussed the role of dipolar azomethine phos-
trapped by intra- and intermolecular [2+1] cycloaddition at phaylides [R2C=N+(R)–P–(RЈ)–W(CO)5] in the reaction of
C=C and CϵC bonds, respectively.[9]
diimines with phosphinidene–W(CO)5 complexes giving bi-
cyclic 1,4,2-diazaphospholanes. Quantum chemical calcula-
tions for an uncomplexed model system suggested that the
products resulted from an intramolecular [3+2] cycload-
dition of the 1,3-dipole at an imine C=N bond rather than
from an insertion of the latter in the C–P bond of the aza-
phosphiridine valence isomer of the dipole. The analogy to
these two reports, as well as the highly dipolarophilic char-
acter of the C=S bond of thiones,[27] suggests that 1,3,2-
dithiaphospholanes 12 result from a [3+2] cycloaddition re-
action of thiocarbonyl-phosphaylide 15 and thione 16
(Scheme 8). It is not clear, however, whether such a cycload-
dition would take a concerted or a stepwise (via diradical
17) pathway. Computational studies[28] of the closely related
cycloaddition reaction of thiobenzophenone S-methylide
–
(Ph2C=S+–CH2 ) and thiobenzophenone yielding 4,4,5,5-
tetraphenyl-1,3-dithiolane have revealed that the stepwise
biradical process has a lower activation energy than the
concerted one, which would lead to the regioisomeric and
thermodynamically favoured 2,2,4,4-tetraphenyl-1,3-dithi-
olane. We note that the regiochemistry of the formation of
1,3,2-dithiaphospholanes 12 corresponds to the regiochemi-
stry that leads to 4,4,5,5-tetraphenyl-1,3-dithiolane and may
hint toward the stepwise diradical process.
Is thiocarbonyl-phospha-ylide 15 the only possible cyclo-
addition partner to trap thioketone 16 or are the bicyclic
valence isomers 10 and 11 likely candidates, too? To answer
this question, we investigated the reaction of 10a with
thiobenzophenone (Scheme 9) and were pleased to find that
Scheme 8. Suggested mechanism for the formation of 11a and 12a
[R = CH=C(Ar)(9-fluorenyl)].
2200
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© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2009, 2195–2207

Spiro[fluorene-phosphirano-thiaphosphole] P-W(CO)5 Complexes
Scheme 9. Synthesis of dithiaphospholane 19 and its metal complex 18.
1
1,3,2-dithiaphospholane 18 (δP
=
52.3 ppm, JP,W
=
the formation of P–W(CO)5 complexes 10 and the smooth
271.0 Hz) was formed readily (3 h, 22 °C) and in 93% yield. cycloaddition reaction with thiobenzophenone, which yields
Notably, even the uncomplexed phosphirane 7a reacted the bicyclic 1,3,2-dithiaphospholane 19. Neither the uncom-
with thiobenzophenone under identical conditions to give plexed phosphirano-thiaphospholes 7 nor their P–W(CO)5
in 93% yield the uncomplexed 1,3,2-dithiaphospholane 19 complexes 10 are thermally robust. Whereas the former
(δP = 26.9 ppm), which in turn could be converted quantita- seem to undergo unspecific decomposition, the latter can
tively into the W(CO)5 complex 18. In contrast to 7a, the enter different reaction channels depending on the solvent
corresponding 6,6-diphenyl derivative 1a did not react and the temperature. In toluene solution at room tempera-
cleanly with thiobenzophenone. The reaction of phospholo- ture, the major pathway includes an α,β-unsaturated thione,
thiaphosphirane 11a with Ph2C=S (toluene, 22 °C, 4 h), on which likely results from a slow [2+1] cycloreversion fol-
the other hand, did not furnish 18 but gave a so-far un- lowed by fragmentation of the so-formed W(CO)5-com-
known product (δP = 101.9 ppm), which was of limited sta- plexed thiophosphinidene moiety. This thione undergoes a
bility under the conditions of column chromatography. rather fast cycloaddition reaction with the precursor mole-
These results suggest that phosphirano-thiaphospholes 7 cule 10 or a monocyclic valence isomer thereof, which may
and 10 react with thioketones, either directly or via ring- result from the cleavage of the P–C ring-fusion bond of 10
opened intermediates such as 15 (Scheme 8), in a formal and can be considered as a so-far unknown thiocarbonyl-
[3+2] cycloaddition, whereas phospholothiaphosphiranes phosphaylide dipole, R2C=S+–P–R, or the corresponding
11 do not react in the same manner.
1,3-diradical form. Although the analogy, in terms of reac-
Based on these results, phospholo-thiaphosphiranes 11 tivity and regiochemistry, with the well-known [3+2] cyclo-
can be excluded as the precursors of 1,3,2-dithiaphosphol- addition reaction of the thiocarbonyl ylide dipole
–
anes 12. The Diels–Alder-like [2π+2σ+2π] cycloaddition re- Ph2C=S+–CH2 and thiobenzophenone is striking, the
action of 10 and a thioketone remains a possibility, also available data do not allow the mechanistic proposals to be
in view of the highly dienophilic character of thiocarbonyl distinguished. At elevated temperatures in toluene solution,
compounds.[29] This cycloaddition could be highly asyn- a valence isomerization transforms the bicyclic phosphir-
chronous, proceeding via 1,5-diradical 17 as an intermedi- anes 10 into phospholo-thiaphosphiranes 11. Again, the
ate in the extreme case. Because the reaction of 10a with R2C=S+–P–R dipole is a likely intermediate. In acetonitrile
Ph2C=S takes place at room temperature, the alternative solution at 80 °C, on the other hand, decomplexation of
mechanistic proposal discussed above, namely the [3+2] cy- 10 becomes the major pathway. Although the chemistry of
cloaddition pathway involving phosphaylide 15, would re- phosphiranes 10 is remarkable, not least by comparison
quire 15 to be in equilibrium with 10a already at room tem- with the different thermal reactivities of the related 6,6-di-
perature, but not to undergo the 1,3-cyclization to yield thi- phenyl-2-thia-1-phosphabicyclo[3.1.0]hex-3-enes 1 and 2,
aphosphirane 11 at this temperature.[30]
their considerable reactivity and low thermal stability do
not suggest that these bicyclic phosphiranes are potential
ligands for catalytically active transition metals.
Conclusions
Spiro[fluorene-9,6Ј-[2]thia[1]phosphabicyclo[3.1.0]hex[3]-
enes] 7 can be prepared conveniently and in high yields
from 1,2-thiaphosphole and 9-diazofluorenes. We have
studied three different reactions of 7, namely acidic hydroly-
sis, leading to cleavage of the P–C ring-fusion bond and the
Experimental Section
General Information: All reactions were carried out under argon by
using standard Schlenk techniques. Rigorously dried solvents were
used. Melting points were measured in open capillaries and are not
formation of monocyclic 3H-1,2-thiaphosphole 2-oxides 8, corrected. Infrared spectra (IR) were recorded with a Bruker Vector
Eur. J. Org. Chem. 2009, 2195–2207
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
2201

S. Maurer, T. Jikyo, G. Maas
FULL PAPER
22 FTIR spectrometer using KBr disks. H (400.13 MHz) and 13C
NMR (100.62 MHz) spectra were measured with a Bruker DRX
400 spectrometer. All NMR spectra were recorded in CDCl3 at
298 K. NMR chemical shifts were referenced to the solvent peak
3-H), 6.94 (d, JH,H = 8.8 Hz, 2 H, o-2-PhH), 7.28–7.60 (m, 14 H,
HPh), 7.61 (d, 3JH,H = 8.8 Hz, 2 H, m-2-PhH) ppm. 13C NMR: δ =
55.4 (s, CH3), 62.6 (d, 1JP,C = 3.7 Hz, C-8), 75.2 (d, 1JP,C = 11.0 Hz,
C-3), 114.0, 126.6, 127.0, 127.5, 127.7, 128.2, 128.4, 129.0, 129.1,
1
3
for 1H (CHCl3: δ = 7.26 ppm) and 13C (CDCl3: δ = 77.00 ppm) 129.3, 129.4, 130.5, 137.8, 138.0, 139.3, 141.1, 141.9, 142.8, 160.4 (s,
2
2
spectra, and for 31P to external 85% H3PO4. When necessary, signal
assignments were made on the basis of COSY, HMBC, TOCSY,
HSQC and NOESY experiments. Mass spectra were recorded with
Finnigan MAT SSQ 7000 and Micromass ZMD (with formic acid)
spectrometers. CI refers to chemical ionization, ESI to electrospray
ionization (ESI).
Starting Materials: 9-Diazofluorene,[31] 2,7-dibromo-9-diazofluo-
rene,[32] and diphenyldiazomethane[33] were prepared by dehydroge-
nation of the corresponding hydrazones using a six-fold excess of
activated MnO2 rather than yellow mercuric oxide. 1,2-Thiaphos-
pholes 5a,b[11] and thiobenzophenone[34] were prepared by follow-
ing published procedures.
p-2-Ph), 194.3 (d, JP,C = 6.6 Hz, COeq), 197.9 (d, JP,C = 30.7 Hz,
COax) ppm. 31P NMR: δ = 124.6 (1JP,W = 261.9 Hz) ppm. MS (CI,
100 eV): m/z (%) = 775 (72) [MH]+, 774 (59) [M]+, 746 (12) [M –
CO]+, 451 (43) [MH – W(CO)5]+, 388 (100). C34H23O6PSW (774.5
+ 0.15 toluene): calcd. C 52.30, H 3.10; found C 52.27, H 3.24.
General Procedure for the Preparation of Spiro[fluorene-9,6Ј-phos-
phirano[1,2]thiaphospholes] 7a–c: A mixture of 1,2-thiaphosphole
5a,b (8.10 mmol) and 9-diazofluorene 6a,b (9.58 mmol) in n-pen-
tane (25 mL) was heated at 60 °C for 1 day in a closed thick-walled
tube. The solvent was evaporated at 0.05 mbar/20 °C. The residue
was recrystallized from chloroform/n-pentane at ambient tempera-
ture.
3-(4-Methoxyphenyl)-5,6,6-triphenyl-1-phospha-2-thiabicyclo[3.1.0]-
hex-3-ene (1b): A solution of 3-(4-methoxyphenyl)-5-phenyl-1,2-
thiaphosphole (5b; 0.600 g, 2.10 mmol) and diazodiphenylmethane
(0.490 g, 2.50 mmol) in toluene (18 mL) was heated at 70 °C until
the red color of the diazo compound had disappeared (24 h). The
solvent was removed in vacuo and the residue was washed twice
with n-pentane. The product was obtained as a pale-yellow solid
3Ј,5Ј-Diphenylspiro[fluorene-9,6Ј-[2]thia[1]phosphabicyclo[3.1.0]hex-
[3]ene] (7a): Synthesis by the general procedure from 1,2-thiaphos-
phole 5a (2.06 g, 8.10 mmol) and 9-diazofluorene (6a; 1.84 g,
9.58 mmol) provided 7a as a colourless crystalline solid (2.81 g,
83%); m.p. 191 °C (dec.). IR (KBr): ν = 1596 (w), 1573 (w), 1491
˜
(m), 1447 (w), 1442 (s), 937 (m), 775 (s), 761 (s), 732 (vs), 703 (s),
690 (m) cm–1. 1H NMR: δ = 6.00 (d, 3JH,H = 7.8 Hz, 1 H, 1-HFluo),
3
3
(0.898 mg, 94%); m.p. 181 °C (dec.). IR (KBr): ν = 1603 (s), 1507
˜
6.54 (d, JP,H = 4.5 Hz, 1 H, 4Ј-H), 6.88 (dt, JH,H = 7.6, 1.0 Hz, 1
H, 2-HFluo), 7.25–7.27 (m, 3 H, 3-HFluo, 7-HFluo, 8-HFluo), 7.40 (m,
4 H, 6-HFluo, m/p-3Ј-PhH), 7.62 (m, 2 H, o-3Ј-PhH), 7.84 (d, 3JH,H
= 7.6 Hz, 1 H, 4-HFluo), 7.95 (d, 3JH,H = 7.3 Hz, 1 H, 5-HFluo) ppm.
(s), 1491 (s), 1443 (s), 1251 (s), 1176 (s), 1031 (m), 831 (m), 763
3
(m), 697 (vs) cm–1. 1H NMR: δ = 3.75 (s, 3 H, CH3), 6.45 (d, JP,H
3
= 4.6 Hz, 1 H, 4-H), 6.72 (d, JH,H = 8.7 Hz, 2 H, HPh), 6.78 (m,
1
1
13C NMR: δ = 34.4 (d, JP,C = 49.8 Hz, C-5Ј), 72.8 (d, JP,C
=
2 H, HPh), 6.94 (m, 4 H, HPh), 7.09–7.29 (m, 9 H, HPh), 7.47 (d,
1
3JH,H = 7.2 Hz, 2 H, HPh) ppm. 13C NMR: δ = 42.2 (d, JP,C
=
3
47.6 Hz, C-6Ј), 119.6 (s, CFluo-5), 119.9 (s, CFluo-4), 122.8 (d, JP,C
1
49.0 Hz, C-5), 55.3 (s, CH3) 72.8 (d, JP,C = 41.0 Hz, C-6), 113.5,
125.4, 125.5, 126.5, 126.7, 127.4, 127.7, 127.8, 128.2, 128.3, 128.4,
129.0, 129.3, 129.6, 130.1, 130.7, 131.2, 131.7, 132.0, 133.6, 135.1,
137.6, 137.9, 141.6, 141.8, 143.4, 143.8, 158.5 (s, p-3-Ph) ppm. 31P
NMR: δ = –78.3 ppm. MS (CI, 100 eV): m/z (%) = 451 (100)
[MH]+, 450 (51) [M]+, 285 (46) [MH – CPh2]+. C29H23OPS (450.5):
calcd. C 77.31, H 5.15; found C 77.37, H 5.44.
= 11.7 Hz, CFluo-8), 124.3 (s, CFluo-6), 125.5 (s, CFluo-2), 125.9 (s,
C
Fluo-7), 126.2 (s, CFluo-3), 126.8 (s, o-3Ј-Ph), 126.9 (s, CFluo-1),
2
127.9 (s, m-3Ј-Ph), 128.9 (s, p-3Ј-Ph), 129.2 (d, JP,C = 3.7 Hz, C-
4), 134.2, 138.6, 138.8, 140.5, 141.2, 144.6, 145.8 ppm. 31P NMR:
δ = –51.7 ppm. MS (CI, 100 eV): m/z (%) = 420 (15) [MH]+, 419
(49) [M]+, 387 (20) [MH – S]+, 255 (100) [M – C13H8]+. C28H19PS
(418.5): calcd. C 80.36, H 4.58; found C 80.45, H 4.66.
1,2-Thiaphospholo[2,3-a]phosphirane–W(CO)5 Complex 2b and
Pentacarbonyl[(3aS*,8R*)-2-(4-methoxyphenyl)-3a,8-diphenyl-3a,8-
dihydroisophosphindolo[2,1-b][1,2]thiaphosphole-κP]tungsten (3b): A
solution of hexacarbonyltungsten (0.500 g, 1.40 mmol) in tetra-
hydrofuran (100 mL) was placed in a photolysis apparatus and irra-
diated for 60 min using a 150-W medium-pressure mercury lamp.
The yellow solution of the [W(CO)5(thf)] complex formed was
added to a solution of phosphirane 1b (0.200 g, 0.440 mmol) in
THF (10 mL) and the solution was stirred for 8 h. At this point, a
mixture of 2b and 3b was present (approximately 2:1 ratio), from
which pure 2b could not be isolated due to continuous rearrange-
ment into 3b. [Column chromatography with toluene/pentane (1:6)
as eluent gave a fraction containing at best a 74:26 mixture of 2b
and 3b.] The solution was stirred for a further 16 h, the solvent was
removed in vacuo and the residue was purified by chromatography
over silica gel with toluene/cyclohexane (1:1) to give 3b as an off-
white solid (0.270 g, 80%).
3Ј-(4-Methoxyphenyl)-5Ј-phenylspiro[fluorene-9,6Ј-[2]thia[1]phos-
phabicyclo[3.1.0]hex[3]ene] (7b): Synthesis by the general procedure
from 1,2-thiaphosphole 5b (2.30 g, 8.10 mmol) and 9-diazofluorene
(6a; 1.84 g, 9.58 mmol) gave 7b as a colorless crystalline solid
(2.76 g, 76%); m.p. 180 °C (dec.). IR (KBr): ν = 1605 (s), 1507 (s),
˜
1443 (s), 1431 (m), 1297 (m), 1217 (vs), 1176 (s), 1036 (m), 810 (s),
734 (s), 700 (s) cm–1. 1H NMR: δ = 3.85 (s, 3 H, CH3), 6.00 (d,
3
3JH,H = 7.8 Hz, 1 H, 1-HFluo), 6.41 (d, JP,H = 4.3 Hz, 1 H, 4Ј-H),
2
6.88 (t, 3JH,H = 7.1 Hz, 1 H, 2-HFluo), 6.93 (d, JP,H = 8.8 Hz, 2 H,
m-3Ј-PhH), 7.25–7.27 (m, 3 H, 3-HFluo, 7-HFluo, 8-HFluo), 7.40 (t,
3
3JH,H = 6.9 Hz, 1 H, 6-HFluo), 7.55 (d, JH,H = 8.8 Hz, 2 H, o-3Ј-
3
3
PhH), 7.84 (d, JH,H = 7.6 Hz, 1 H, 4-HFluo), 7.93 (d, JH,H
=
7.8 Hz, 1 H, 5-HFluo) ppm. 13C NMR: δ = 34.8 (d, 1JP,C = 49.0 Hz,
C-5Ј), 55.4 (s, CH3), 72.9 (d, JP,C = 48.3 Hz, C-6Ј), 114.2, 119.5,
119.9, 122.8, 124.3, 125.4, 125.9, 126.1, 126.9, 127.4 (d, JP,C
1
2
=
3.7 Hz, C-4Ј), 127.8, 128.3, 138.8, 140.5, 141.1, 144.6, 145.4, 160.3
(s, p-3Ј-Ph) ppm. 31P NMR: δ = –54.2 ppm. MS (CI, 100 eV): m/z
(%) = 449 (21) [M]+, 285 (100) [M – C13H8]+. C29H21OPS (448.5):
calcd. C 77.66, H 4.72; found C 77.40, H 4.74.
Data for 2b (in admixture with 3b): 1H NMR: δ = 3.73 (s, 3 H,
3
OCH3), 6.09 (d, JP,H = 17.2 Hz, 1 H, 4-H), 6.48 (d, J = 8.6 Hz, 2
H), 6.67 (d, J = 8.8 Hz, 2 H), 6.91 (m, 5 H), 7.49–7.60 (m, 10
2,7-Dibromo-3Ј,5Ј-diphenylspiro[fluorene-9,6Ј-[2]thia[1]phosphabicy-
clo[3.1.0]hex[3]ene] (7c): Synthesis by the general procedure from
1,2-thiaphosphole 5a (2.06 g, 8.10 mmol) and 2,7-dibromo-9-diazo-
fluorene (6b; 3.35 g, 9.58 mmol) at 70 °C. The crude product was
dissolved in dichloromethane, the residue was filtered off and the
solvent was evaporated at 0.05 mbar/20 °C to furnish 7c as a yellow
H) ppm. 31P NMR: δ = –57.5 ppm (1JP,W = 268.8 Hz).
Data for 3b: M.p. 189 °C (dec.). IR (KBr): ν = 2077 (s), 1939 (vs,
˜
br), 1604 (m), 1508 (m), 1444 (m), 1254 (m), 1176 (m), 1031 (m),
1
700 (m), 592 (m), 571 (m) cm–1. H NMR: δ = 3.86 (s, 3 H, CH3),
2
3
5.29 (d, JP,H = 13.9 Hz, 1 H, 8-H), 6.20 (d, JP,H = 18.4 Hz, 1 H,
2202
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Eur. J. Org. Chem. 2009, 2195–2207

Spiro[fluorene-phosphirano-thiaphosphole] P-W(CO)5 Complexes
1
solid (4.57 g, 98%); m.p. 189 °C (dec.). IR (KBr): ν = 2064 (w),
3JH,H = 7.1 Hz, 1 H, 1-HFluo) ppm. 13C NMR: δ = 51.7 (d, JP,C
=
˜
1
1595 (m), 1566 (m), 1445 (s), 1396 (s), 1259 (w), 1070 (m), 920 (m),
52.7 Hz, C-3), 52.9 (d, JP, C = 55.6 Hz, CFluo-9), 55.4 (s, CH3),
2
4
805 (s), 759 (s), 696 (s) cm–1. 1H NMR: δ = 6.06 (d, 4JH,H = 1.8 Hz,
114.0 (s, m-5-Ph), 119.7 (d, JP,C = 3.7 Hz, C-4), 120.0 (d, JP,C =
3
3
1 H, 1-HFluo), 6.51 (d, JP,H = 4.5 Hz, 1 H, 4Ј-H), 7.26–7.45 (m, 5
1.5 Hz, CFluo-5), 120.3 (s, CFluo-4), 127.0 (d, JP,C = 2.9 Hz, CFluo-
1), 127.4 (d, JP,C = 2.2 Hz, CFluo-2), 127.4 (s, ipso-5-Ph), 127.5 (d,
3
4
H, 3Ј-PhH), 7.52 (dd, JH,H = 8.2, 1.6 Hz, 1 H, 3-HFluo), 7.63 (m,
3
5
3 H, 4-HFluo, 6-HFluo, 8-HFluo), 7.74 (d, JH,H = 8.1 Hz, 1 H, 5-
JP,C = 3.6 Hz, C-3-Ph), 127.7 (d, JP,C = 2.9 Hz, CFluo-6), 127.9 (s,
HFluo) ppm. 13C NMR: δ = 34.0 (d, JP,C = 50.5 Hz, C-5Ј), 73.3 (d,
o-5-Ph), 128.1 (d, 3JP,C = 2.9 Hz, CFluo-8), 128.3 (d, 5JP,C = 2.2 Hz,
1
1JP,C = 48.3 Hz, C-6Ј), 112.0, 120.7, 121.0, 122.1, 125.9, 127.1,
127.6, 128.3, 128.6, 129.1, 129.4, 133.7, 136.7, 137.5, 138.9, 141.9,
146.5, 146.6 ppm. 31P NMR: δ = –47.8 ppm. MS (CI, 100 eV): m/z
(%) = 579/577/575 (1.3/2.6/1.6) [M]+, 255 (100) [M – C13H6Br2]+.
C28H17Br2PS (576.3): calcd. C 58.36, H 2.97; found C 58.35, H
3.50.
C
Fluo-3), 128.5 (m, C-3-Ph), 128.6 (d, 4JP,C = 2.9 Hz, CFluo-7), 132.6
2
3
(d, JP,C = 8.1 Hz, ipso-3-Ph), 137.2 (d, JP,C = 3.7 Hz, CFluo-4a or
Fluo-4b), 137.6 (d, JP,C = 4.4 Hz, CFluo-4a or CFluo-4b), 138.2 (s,
3
C
C-5), 141.7 (d, 2JP,C = 3.7 Hz, CFluo-8a or CFluo-9a), 141.8 (d, 2JP,C
= 3.7 Hz, CFluo-8a or CFluo-9a), 160.3 (s, p-5-Ph) ppm. 31P NMR:
δ = 79.2 ppm. MS (CI, 100 eV): m/z (%) = 467 (100) [MH]+, 301
(8) [M – fluorenyl]+, 165 (4) [fluorenyl]+.
General Procedure for the Preparation of 3H-1,2λ5-Thiaphosphole
2-Oxides 8a–c: A 2  ethereal HCl solution (2.1 mL) containing a
small amount of water was added to the vigorously stirred solution
of phosphirano-thiaphosphole 7 (95.2 µmol) in dichloromethane
(20 mL) at 20 °C. Within minutes, the solution had turned yellow.
After 1 h, the solvent was removed at 0.05 mbar/20 °C. The crude
product was purified by recrystallization from dichloromethane/n-
pentane at 0 °C.
2-(2,7-Dibromo-9H-fluoren-9-yl)-3,5-diphenyl-2,3-dihydro-1,2-thia-
phosphole 2-Oxide (8c): Synthesis by the general procedure from 7c
(29.9 mg, 95.2 µmol). Yellow crystalline solid (18.1 mg, 60%), m.p.
222 °C (dec.). IR (KBr): ν = 1595 (m), 1568 (m), 1489 (m), 1448
˜
(s), 1394 (m), 1261 (m), 1200 (vs, P=O), 1062 (s, C–Br), 907 (m),
888 (m), 813 (s), 753 (s), 725 (s), 694 (s) cm–1. H NMR: δ = 3.37
1
(dd, 2JP,H = 6.6, 3JH,H = 3.3 Hz, 1 H, 3-H), 5.12 (d, 2JP,H = 25.5 Hz,
3
3
1 H, 9-HFluo), 5.79 (dd, JP,H = 35.6, JH,H = 3.5 Hz, 1 H, 4-H),
6.62 (dd, JH,H = 5.4, 1.6 Hz, 2 H, o-3-PhH), 7.22 (m, 3 H, m/p-3-
2-(9H-Fluoren-9-yl)-3,5-diphenyl-2,3-dihydro-1,2-thiaphosphole 2-
Oxide (8a): Synthesis by the general procedure from 7a (40.0 mg,
95.2 µmol). Pale-yellow crystalline solid (29.2 mg, 70 %), m.p.
3
PhH), 7.36 (m, 3 H, m/p-5-PhH), 7.43 (m, 2 H, o-5-PhH), 7.57 (d,
3JH,H = 8.3 Hz, 1 H, 3-HFluo), 7.69 (d, JH,H = 8.1 Hz, 1 H, 6-
3
229 °C (dec.). IR (KBr): ν = 1598 (w), 1490 (m), 1445 (s), 1203 (vs,
˜
3
3
HFluo), 7.70 (d, JH,H = 8.0 Hz, 1 H, 4-HFluo), 7.75 (d, JH,H
=
1
P=O), 917 (m), 809 (m), 756 (s), 734 (vs), 693 (s) cm–1. H NMR:
8.3 Hz, 1 H, 5-HFluo), 8.07 (s, 1 H, 8-HFluo), 8.14 (s, 1 H, 1-
2
3
2
δ = 3.40 (dd, JP,H = 6.3, JH,H = 3.3 Hz, 1 H, 3-H), 5.17 (d, JP,H
= 25.5 Hz, 1 H, 9-HFluo), 5.73 (dd, JP,H = 34.9, JH,H = 3.3 Hz, 1
HFluo) ppm. 13C NMR: δ = 52.0 (d, JP,C = 54.2 Hz, C-3), 52.9 (d,
1
3
3
1JP,C = 54.2 Hz, CFluo-9), 121.1 (d, JP,C = 5.1 Hz, C-4), 121.3 (d,
4
3
H, 4-H), 6.53 (dd, JH,H = 7.6, 2.0 Hz, 2 H, o-3-PhH), 7.14 (m, 3
4JP,C = 1.5 Hz, CFluo-5), 121.6 (d, JP,C = 1.5 Hz, CFluo-4), 121.7
4
H, m/p-3-PhH), 7.25 (t, 3JH,H = 7.5 Hz, 1 H, 2-HFluo), 7.33 (t, 3JH,H
= 8.2 Hz, 1 H, 6-HFluo), 7.36 (m, 3 H, m/p-3-PhH), 7.41 (m, 2 H,
4
4
(d, JP,C = 2.9 Hz, CFluo-Br), 121.9 (d, JP,C = 2.9 Hz, CFluo-Br),
126.7 (s, o-5-Ph), 128.0 (d, 2JP,C = 2.9 Hz, m/p-3-Ph), 128.4 (d, 3JP,C
= 5.1 Hz, o-3-Ph), 128.8 (s, m-5-Ph), 129.4 (s, p-5-Ph), 130.0 (d,
3
3
o-5-PhH), 7.45 (t, JH,H = 7.7 Hz, 1 H, 3-HFluo), 7.55 (t, JH,H
7.6 Hz, 1 H, 7-HFluo), 7.90 (d, JH,H = 7.6 Hz, 1 H, 4-HFluo), 7.94
=
3
3JP,C = 2.9 Hz, CFluo-1), 130.8 (d, JP,C = 2.2 Hz, CFluo-8), 131.7
3
3
3
(d, JH,H = 8.1 Hz, 2 H, 5-HFluo, 8-HFluo), 8.01 (d, JH,H = 7.7 Hz,
2
5
(d, JP,C = 8.1 Hz, ipso-3-Ph), 131.8 (d, JP,C = 2.2 Hz, CFluo-3),
132.2 (d, JP,C = 2.2 Hz, CFluo-6), 134.4, 139.0 (d, JP,C = 4.4 Hz,
1 H, 1-HFluo) ppm. 13C NMR: δ = 51.8 (d, JP,C = 53.4 Hz, C-3),
1
4
3
1
4
53.0 (d, JP,C = 55.6 Hz, CFluo-9), 120.0 (s, CFluo-5), 120.4 (d, JP,C
= 1.5 Hz, CFluo-4), 121.5 (d, JP,C = 4.4 Hz, C-4), 126.6 (s, o-5-Ph),
3
CFluo-4a or CFluo-4b), 139.3 (d, JP,C = 2.2 Hz, CFluo-4a or CFluo
-
-
2
4b), 139.4 (s, ipso-5-Ph), 139.6/139.7 (each d, 2JP,C = 5.9 Hz, CFluo
3
4
127.0 (d, JP,C = 2.9 Hz, CFluo-1), 127.5 (d, JP,C = 2.9 Hz, CFluo
-
-
8a, CFluo-9a) ppm. 31P NMR: δ = 78.3 ppm. MS (CI, 100 eV): m/z
(%) = 597/595/593 (46/100/43) [MH]+. C28H19Br2OPS (594.3):
calcd. C 56.59, H 3.22; found C 56.61, H 3.04.
2), 127.6 (d, 4JP,C = 3.7 Hz, m-3-Ph), 127.7 (d, 5JP,C = 2.9 Hz, CFluo
6), 128.2 (d, 3JP,C = 3.7 Hz, CFluo-8), 128.4 (d, 5JP,C = 2.2 Hz, CFluo
-
3), 128.6 (m, o/m-3-Ph), 128.7 (s, m-5-Ph), 128.7 (d, 4JP,C = 2.9 Hz,
2
CFluo-7), 129.2 (s, p-5-Ph), 132.4 (d, JP,C = 8.1 Hz, ipso-3-Ph),
135.0 (d, JP,C = 4.4 Hz, C-5), 137.2 (d, JP,C = 4.4 Hz, CFluo-4a),
General Procedure for the Preparation of Complexes 10a–c: A solu-
tion of hexacarbonyltungsten (3.71 mmol) in tetrahydrofuran
(300 mL) was placed in a photolysis apparatus and irradiated for
60 min with a 150-W medium-pressure mercury lamp. The yellow
solution of the formed complex [W(CO)5(thf)] was transferred
3
3
3
137.6 (d, JP,C = 2.9 Hz, CFluo-4b), 138.8 (s, ipso-5-Ph), 141.78/
141.84 (d, JP,C = 5.9 Hz, CFluo-8a, CFluo-9a) ppm. 31P NMR: δ =
2
79.2 ppm. MS (CI, 100 eV): m/z (%) = 437 (100) [MH]+, 271 (12)
[M – fluorenyl]+, 165 (7) [fluorenyl]+. C28H21OPS (436.5): calcd. C through a cannula into a flask containing the solid phosphirane 7
77.04, H 4.85; found C 77.18, H 4.73.
(3.27 mmol) and the mixture was stirred for 1 day. The solvent was
removed in vacuo. The resulting oil was purified by chromatog-
raphy over silica gel with toluene/cyclohexane (1:3) as eluent.
2-(9H-Fluoren-9-yl)-5-(4-methoxyphenyl)-3-phenyl-2,3-dihydro-1,2-
thiaphosphole 2-Oxide (8b): Synthesis by the general procedure
from 7b (42.9 mg, 95.2 µmol). Yellow crystalline solid (33.9 mg,
Pentacarbonyl(3Ј,5Ј-diphenylspiro[fluorene-9,6Ј-[2]thia[1]phospha-
bicyclo[3.1.0]hex[3]ene]-κP)tungsten (10a): Synthesis by the general
76%), m.p. 180 °C (dec.). IR (KBr): ν = 1605 (s), 1508 (s), 1447
˜
(m), 1300 (w), 1258 (s), 1205 (vs, P=O), 1179 (s), 1027 (m), 833 procedure from [W(CO)6] (1.31 g, 3.71 mmol) and 7a (1.37 g,
1
2
(m), 808 (m), 739 (s), 519 (m) cm–1. H NMR: δ = 3.42 (dd, JP,H 3.27 mmol). Yellow solid (2.35 g, 97%), m.p. 185 °C (dec.). IR
3
2
= 6.3, JH,H = 3.3 Hz, 1 H, 3-H), 5.16 (d, JP,H = 25.5 Hz, 1 H, 9-
(KBr): ν = 2076 (s), 1995 (m), 1935 (vs, br), 1445 (m), 1261 (w),
˜
3
3
3
HFluo), 5.62 (dd, JP,H = 35.0, JH,H = 3.4 Hz, 1 H, 4-H), 6.53 (dd,
773 (m), 754 (m), 736 (m) cm–1. 1H NMR: δ = 5.98 (d, JH,H
=
3JH,H = 5.4, 1.6 Hz, 2 H, o-3-PhH), 6.89 (d, JH,H = 8.8 Hz, 2 H,
8.0 Hz, 1 H, 1-HFluo), 6.48 (d, 3JP,H = 16.9 Hz, 1 H, 4Ј-H), 6.73 (d,
3
m-5-PhH), 7.14 (m, 3 H, m/p-3-PhH), 7.24 (t, JH,H = 7.5 Hz, 1 H, 3JH,H = 7.6 Hz, 1 H, 7Ј-HPh), 6.89 (t, 3JH,H = 7.2 Hz, 1 H, 2-HFluo),
3
3
3
3
2-HFluo), 7.33 (t, JH,H = 7.7 Hz, 1 H, 6-HFluo), 7.35 (d, JH,H
=
7.15 (t, JH,H = 7.1 Hz, 1 H, 8Ј-HPh), 7.25–7.45 (m, 8 H, HPh
,
3
3
8.6 Hz, 2 H, o-5-PhH), 7.45 (t, JH,H = 7.5 Hz, 1 H, 3-HFluo), 7.55
HFluo), 7.58 (m, 3 H, 10Ј-HPh, o-3Ј-PhH), 7.84 (d, JH,H = 7.6 Hz,
(t, JH,H = 7.3 Hz, 1 H, 7-HFluo), 7.89 (d, JH,H = 7.6 Hz, 1 H, 4- 1 H, 4-HFluo), 7.88 (d, 3JH,H = 7.8 Hz, 1 H, 11Ј-HPh), 7.95 (d, 3JH,H
3
3
= 7.6 Hz, 1 H, 5-HFluo) ppm. 13C NMR: δ = 35.2 (d, JP, C
=
3
1
HFluo), 7.93 (d, JH,H = 8.1 Hz, 2 H, 5-HFluo, 8-HFluo), 8.00 (d,
Eur. J. Org. Chem. 2009, 2195–2207
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
2203

S. Maurer, T. Jikyo, G. Maas
FULL PAPER
30.0 Hz, C-5Ј), 67.0 (d, JP,C = 28.5 Hz, C-6Ј), 120.0, 120.3, 124.7,
1
chromatography on silica gel with toluene/cyclohexane (1:2) to give
12a as a 2.3:1 mixture of isomers (26 mg, 68% yield).
2
125.5, 126.5, 126.6, 126.8, 127.1, 128.4, 128.6 (d, JP,C = 28.5 Hz,
C-4Ј), 129.1, 129.6, 130.1, 130.9, 133.1, 135.7, 139.9, 140.1, 141.4,
Pentacarbonyl(3Ј,5Ј-diphenylspiro[fluorene-9,2Ј-[6]thia[1]phospha-
bicyclo[3.1.0]hex[3]ene]-κP)tungsten (11a): Yellow solid (0.99 g,
2
2
141.7, 146.7, 194.1 (d, JP,C = 7.3 Hz, COeq), 197.0 (d, JP, C
=
41.7 Hz, COax) ppm. 31P NMR: δ = –35.2 (1JP,W = 277.8 Hz) ppm.
MS (CI, 100 eV): m/z (%) = 742 (3) [M]+, 714 (22) [M – CO]+, 711
(90), 709 (100) [M – S]+, 388 (100) [MH – S – W(CO)5]+ 357 (77).
C33H19O5PSW (742.4): calcd. C 53.39, H 2.58; found C 53.36, H
2.65.
80%), m.p. 140 °C (dec.). IR (KBr): ν = 2078 (m), 1996 (m), 1948
˜
(vs), 1444 (w), 742 (w) cm–1. 1H NMR: δ = 6.66 (d, 3JH,H = 7.3 Hz,
3
2 H, o-3Ј-PhH), 6.94 (t, JH,H = 7.7 Hz, 2 H, m-3Ј-PhH), 7.04 (t,
3JH,H = 7.3 Hz, 1 H, p-3Ј-PhH), 7.17 (m, 1 H, 1-HFluo), 7.27 (m, 5
H, 2-HFluo, 8-HFluo, p/m-5Ј-PhH), 7.46 (m, 4 H, 4Ј-H, 3-HFluo, 6-
3
Pentacarbonyl(3Ј-(4-methoxyphenyl)-5Ј-phenylspiro[fluorene-9,6Ј-
[2]thia[1]phosphabicyclo[3.1.0]hex[3]ene]-κP)tungsten (10b): Synthe-
sis by the general procedure from [W(CO)6] (1.31 g, 3.71 mmol)
and 7b (1.46 g, 3.27 mmol). Yellow solid (2.20 g, 87%), m.p. 145 °C
HFluo, 7-HFluo), 7.70 (d, JH,H = 7.8 Hz, 2 H, o-5Ј-PhH), 7.84 (d,
3
3JH,H = 7.6 Hz, 1 H, 4-HFluo), 7.92 (d, JH,H = 7.3 Hz, 1 H, 5-
1
HFluo) ppm. 13C NMR: δ = 59.9 (d, JP,C = 5.5 Hz, C-5Ј), 69.8 (d,
1JP,C = 9.2 Hz, C-2Ј), 120.6, 121.7, 124.4, 124.6, 125.3, 126.6, 127.2,
(dec.). IR (KBr): ν = 2078 (s), 2003 (m), 1937 (vs, br), 1598 (m),
˜
128.2, 128.3, 128.6, 128.9, 129.8, 134.5, 135.6, 140.0, 141.3, 142.7,
1444 (m), 1259 (m), 1177 (m) cm–1. 1H NMR: δ = 3.86 (s, 3 H,
2
2
143.2, 144.0 (d, JP,C = 7.3 Hz, C-4Ј), 193.0 (d, JP, C = 7.3 Hz,
3
3
2
COeq), 196.1 (d, JP,C = 41.0 Hz, COax) ppm. 31P NMR: δ = –6.4
CH3), 6.00 (d, JH,H = 7.8 Hz, 1 H, 1-HFluo), 6.35 (d, JP, H
=
3
(1JP,W = 291.6 Hz) ppm. MS (CI, 100 eV): m/z (%) = 742 (39)
[M]+, 713 (80) [M – CO – 1]+, 711/709 (80/100) [M – S + 1/–1]+,
686 (10) [M – 2CO]+, 658 (17) [M – 3CO]+, 630 (7) [M – 4CO +
1]+, 602 (13) [M – 5CO]+, 570 (10) [M – S – 5CO]+, 419 (12) [M –
W(CO)5]+, 387 (54) [M – S – W(CO)5]+. C33H19O5PSW (742.4):
calcd. C 53.39, H 2.58; found C 53.56, H 2.70.
17.2 Hz, 1 H, 4Ј-H), 6.72 (d, JH,H = 7.8 Hz, 1 H, 7Ј-HPh), 6.89 (t,
3JH,H = 8.1 Hz, 1 H, 2-HFluo), 6.95 (d, JH,H = 8.8 Hz, 2 H, m-3Ј-
3
3
PhH), 7.14 (t, JH,H = 7.5 Hz, 1 H, 8Ј-HPh), 7.15–7.29 (m, 2 H, 3-
3
H
Fluo, 7-HFluo), 7.35 (m, 2 H, 8-HFluo, 9-HFluo), 7.46 (t, JH,H
=
7.4 Hz, 1 H, 6-HFluo), 7.52 (d, 3JH,H = 8.8 Hz, 2 H, o-3Ј-PhH), 7.56
3
3
(t, JH,H = 6.7 Hz, 1 H, 10Ј-HPh), 7.83 (d, JH,H = 7.6 Hz, 1 H, 4-
3
3
HFluo), 7.88 (d, JH,H = 7.3 Hz, 1 H, 11Ј-HPh), 7.95 (d, JH,H
=
Pentacarbonyl{6-[(E)-2-(9H-fluoren-9-yl)-2-phenylethenyl]-3,5,6-
triphenylspiro[7,8-dithia-1-phosphabicyclo[3.2.1]oct-3-ene-2,9Ј-
fluorene]-κP}tungsten (12a): Yellow solid (0.13 g, 7%), m.p. 230 °C
7.6 Hz, 1 H, 5-HFluo) ppm. 13C NMR: δ = 35.4 (d, 1JP,C = 30.7 Hz,
1
C-5Ј), 55.4 (s, CH3), 67.0 (d, JP,C = 28.5 Hz, C-6Ј), 114.4, 120.1,
124.8, 125.5, 125.7, 126.5, 126.7, 126.9, 127.1, 128.0, 128.4, 128.5,
(dec.). IR (KBr): ν = 2075 (s), 1991 (w), 1950 (vs), 1445 (m), 1030
˜
2
129.0, 130.1, 130.9, 135.9, 140.1, 141.6, 160.7, 194.2 (d, JP,C
=
(w), 741 (s), 699 (s) cm–1. 1H NMR: δ = 5.07 (s, 1 H, 9-HFluo), 6.58
6.6 Hz, COeq), 197.3 (d, JP,C = 41.0 Hz, COax) ppm. 31P NMR: δ
= –37.0 (1JP,W = 275.6 Hz) ppm. MS (CI, 100 eV): m/z (%) = 773
(1) [MH]+, 744 (9) [M – CO]+, 740 (33) [M – S]+, 417 (34) [MH –
S – W(CO)5]+, 285 (100) [C16H13OPS (= 5b) + 1]+. C34H21O6PSW
(772.4): calcd. C 52.87, H 2.74; found C 52.39, H 2.93.
2
3
3
(dd, JH,H = 8.2, 1.1 Hz, 1 H, o-1-PhH), 6.76 (dd, JH,H = 8.5,
1.4 Hz, 1 H, o-2-PhH), 6.84 (m, 3 H, m/p-1-PhH), 6.96 (m, 4 H,
3
m-2-PhH, HPh), 7.04 (t, JH,H = 7.2 Hz, 1 H, p-2-PhH), 7.17 (m, 3
H, 4-H, HPh, HFluo), 7.27 (m, 2 H, HPh, HFluo), 7.39–7.58 (m, 17
H, HPh, HFluo), 7.62 (d, 3JH,H = 7.3 Hz, 1 H, HFluo), 7.70 (dd, 3JH,H
3
Pentacarbonyl(2,7-dibromo-3Ј,5Ј-diphenylspiro[fluorene-9,6Ј-[2]thia-
[1]phosphabicyclo[3.1.0]hex[3]ene]-κP)tungsten (10c): Synthesis by
the general procedure from [W(CO)6] (1.31 g, 3.71 mmol) and 7c
(1.88 g, 3.27 mmol). Yellow solid (2.44 g, 83%), m.p. 211 °C (dec.).
= 6.7, 1.9 Hz, 1 H, HFluo), 7.77 (d, JH,H = 7.6 Hz, 1 H, HFluo),
3
3
8.28 (d, JH,H = 7.6 Hz, 1 H, HFluo), 8.32 (dd, JH,H = 7.1, 2.5 Hz,
1 H, HFluo), 8.50 (m, 1 H, HFluo) ppm. 13C NMR: δ = 51.6 (s,
CFluo-9), 60.6 (d, JP,C = 3.7 Hz, C-2), 74.7 (d, JP,C = 2.2 Hz, C-
5), 84.7 (d, JP,C = 2.9 Hz, C-6), 119.6, 120.8, 125.5, 125.6, 126.4,
1
4
5
IR (KBr): ν = 2078 (s), 1997 (m), 1937 (vs, br), 1594 (m), 1567 (m),
˜
1446 (s), 1396 (m), 1063 (m), 1005 (m), 923 (m), 812 (s) 757 (m),
126.8, 126.8, 127.0, 127.5, 127.5, 127.6, 127.6, 127.7, 127.8, 127.9,
128.9, 129.0, 129.3, 129.8, 131.6, 133.9, 136.6, 140.8, 141.2, 141.6,
141.7, 142.0, 142.5, 143.1, 143.5, 144.5, 145.3, 147.5, 194.0 (d, 2JP,C
700 (m) cm–1. 1H NMR: δ = 6.07 (d, 4JH,H = 1.0 Hz, 1 H, 1-HFluo),
3
3
6.47 (d, JP,H = 17.4 Hz, 1 H, 4Ј-H), 6.71 (d, JH,H = 7.6 Hz, 1 H,
2
= 6.6 Hz, COeq), 197.0 (d, JP,C = 32.9 Hz, COax) ppm. 31P NMR:
7Ј-HPh), 7.19 (m, 1 H, 8Ј-HPh), 7.41–7.50 (m, 5 H, 3-HFluo, 6-HFluo
,
=
3
δ = 54.3 (1 JP, W = 273.2 Hz) ppm. MS (ESI): m/z = 1169
[M + K]+, 1153 [M + Na]+, 1113 [M + K – 2CO]+, 1097 [M +
Na – 2CO]+, 1029 [M + K – 5CO]+, 1013 [M + Na – 5CO]+, 845
[M + K – W(CO)5]+, 829 [M + Na – W(CO)5]+. C61H39O5PS2W
(1130.9): calcd. C 64.79, H 3.48; found C 64.42, H 3.99.
HPh), 7.51 (s, 1 H, 8-HFluo), 7.59 (m, 4 H, HPh), 7.65 (d, JH,H
3
8.0 Hz, 1 H, 4-HFluo), 7.76 (d, JH,H = 8.1 Hz, 1 H, 5-HFluo), 7.87
(d, JH,H = 7.3 Hz, 1 H, 11Ј-HPh) ppm. 13C NMR: δ = 36.6 (d,
3
1JP,C = 25.9 Hz, C-5Ј), 67.4 (d, 1JP,C = 27.8 Hz, C-6Ј), 119.8, 121.2,
2
121.4, 125.3, 126.9, 128.3, 128.6, 129.0, 129.2, 129.3 (d, JP,C
=
6.5 Hz, C-4Ј), 130.2, 132.7, 134.7, 138.0, 139.4, 141.4, 143.6, 144.8,
Thermally Induced Reaction of Complex 10b: A solution of 10b
(1.32 g, 1.68 mmol) in toluene (25 mL) was heated at 80 °C for 3 h.
The solvent was removed in vacuo and the yellow residue was sub-
jected to column chromatography over silica gel with toluene/cyclo-
hexane (3:1) as eluent to give thiaphosphirane 11b (0.91 g, 70%).
When 10b was heated at 50 °C for 24 h, a mixture of 10b, 11b and
12b (two isomers, δP(12b) = 53.6 and 52.2 ppm) was formed (1:3.5:1
by 31P NMR integration), which was not worked up.
2
2
147.4, 193.0 (d, JP,C = 7.3 Hz, COeq), 196.1 (d, JP,C = 39.5 Hz,
COax) ppm. 31P NMR: δ = –30.3 (1JP,W = 280.2 Hz) ppm.
C33H17Br2O5PSW (900.2) +0.4 toluene: calcd. C 45.61, H 2.18;
found C 45.58, H 2.41.
Thermally Induced Reaction of Complex 10a
Procedure A: A solution of 10a (1.25 g, 1.68 mmol) in toluene
(25 mL) was heated at 80 °C for 48 h. The solvent was removed in
vacuo and the brown residue was subjected to column chromatog-
raphy over silica gel with toluene/cyclohexane (1:2) as eluent to give
thiaphosphirane 11a (0.99 g, 80 %) and 1,3,2-dithiaphospholane
12a (0.13 g, 7%) as a 7:1 mixture of isomers (10:1 ratio after re-
peated chromatography).
Pentacarbonyl(5Ј-(4-methoxyphenyl)-3Ј-phenylspiro[fluorene-9,2Ј-
[6]thia[1]phosphabicyclo[3.1.0]hex[3]ene]-κP)tungsten (11b): Yellow
solid (0.91 g, 70%), m.p. 158 °C (dec.). IR (KBr): ν = 2077 (m),
˜
1945 (vs, br), 1260 (m), 1097 (m), 1027 (m), 804 (m) cm–1
.
1H
3
NMR: δ = 3.85 (s, 3 H, CH3), 6.65 (d, JH,H = 7.3 Hz, 2 H, o-3Ј-
PhH), 7.00 (m, 4 H, 1-HFluo, m/p-3Ј-PhH), 7.03 (t, JH,H = 7.3 Hz,
3
Procedure B: A solution of 10a in [D1]chloroform was allowed to
stand at ambient temperature for 4 weeks. The solvent was removed
in vacuo and the residue was purified by preparative thin-layer
1 H, 2-HFluo), 7.42 (m, 2 H, 3-HFluo, 6-HFluo), 7.55 (m, 4 H, 7-
HFluo, 8-HFluo, m-5Ј-PhH), 7.59 (d, 3JH,H = 7.6 Hz, 2 H, o-5Ј-PhH),
2204
www.eurjoc.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2009, 2195–2207

Spiro[fluorene-phosphirano-thiaphosphole] P-W(CO)5 Complexes
3
3
7.84 (d, JH,H = 7.6 Hz, 1 H, 4-HFluo), 7.92 (d, JH,H = 7.8 Hz, 1
1-Ph), 128.8 (m-1-Ph), 129.1 (p-3-Ph), 133.4 (p-1-Ph), 136.4 (C=C-
CH2), 136.8 (m-3-Ph), 138.0 (CFluo-9a), 138.4 (C=C-CH2), 138.5
(ipso-1-Ph), 140.0 (CFluo-8a), 141.0 (CFluo-4a or CFluo-4b), 144.1
(CFluo-4a or CFluo-4b), 144.5 (ipso-3-Ph), 195.5 (CO) ppm. MS (CI,
100 eV): m/z (%) = 373 (100) [MH]+, 105 (69) [C6H7CO]+.
H, 5-HFluo) ppm. 13C NMR: δ = 55.5 (s, CH3), 59.7 (d, JP,C
4.4 Hz, C-5Ј), 69.9 (d, JP,C = 14.6 Hz, C-2Ј), 113.6, 114.3, 119.2,
120.6, 121.8, 123.2, 124.4, 124.4, 124.6, 126.6, 127.2, 127.4, 128.2,
128.3, 128.6, 128.9, 129.0, 129.2, 129.8, 130.2, 140.0, 140.8, 142.8,
=
1
1
2
144.0, 145.2, 146.3, 159.9 (s, p-5Ј-Ph), 193.1 (d, JP, C = 8.0 Hz,
Dithiaphospholane Pentacarbonyltungsten Complex 18
COeq), 196.3 (d, JP,C = 42.4 Hz, COax) ppm. 31P NMR: δ = –6.21
2
(1JP, W = 289.2 Hz) ppm. MS (CI, 100 eV): m/z (%) = 773 (1)
[MH]+, 744 (8) [M – CO]+, 740 (34) [M – S]+, 417 (30) [M – S –
W(CO)5]+, 285 (87) [C16H13OPS (= 5b) + 1]+.
Procedure A: A solution of 10a (40.0 mg, 54.0 µmol) and thioben-
zophenone (21.3 mg, 0.110 mmol) in toluene (10 mL) was stirred
at ambient temperature. A color change from deep-blue to deep-
violet occurred. After 3 h, the solvent was removed at 0.05 mbar/
20 °C. The crude product was purified by thin-layer chromatog-
raphy on silica gel with toluene/cyclohexane (1:1) to give 18 as a
yellow solid (47.0 mg, 93%).
Thermally Induced Reaction of Complex 10c: A solution of 10c
(1.54 g, 1.68 mmol) in toluene (25 mL) was heated at 80 °C for 8 h.
The 31P NMR spectra indicated the presence of a mixture of 10c,
11c and 12c in a 12:70:15 ratio. Efforts to separate thiaphosphirane
complex 11c from this mixture by column chromatography were
unsuccessful because the compound underwent partial decomposi-
tion. NMR spectroscopic data of 11c: 1H NMR: δ = 6.66 (d, 3JH,H
= 7.3 Hz, 2 H, o-3Ј-PhH), 7.00 (t, 3JH,H = 7.7 Hz, 2 H, m-3Ј-PhH),
Procedure B:
A solution of hexacarbonyltungsten (0.40 g,
1.13 mmol) in THF (250 mL) was placed in a photolysis apparatus
and irradiated for 60 min using a 150 W medium-pressure mercury
lamp. The yellow solution of the [W(CO)5(thf)] complex formed
was transferred to a flask containing solid dithiaphospholane 19
(0.62 g, 1.01 mmol) and the mixture was stirred for 1 day. The sol-
vent was removed under reduced pressure. The resulting oil was
purified by chromatography on silica gel with toluene/cyclohexane
(1:1) to give 18 as a yellow solid (0.90 g, 95%); m.p. 233 °C (dec.).
3
7.10 (t, JH,H = 7.3 Hz, 1 H, p-3Ј-PhH), 7.17 (m, 1 H, HPh/Fluo),
7.40–7.70 (m, 11 H, HPh/Fluo) ppm. 31P NMR: δ = –6.92 (1JP,W
=
296.0 Hz) ppm.
Pentacarbonyl(3Ј,5Ј-diphenylspiro[fluorene-9,2Ј-[2H]phosphole])tung-
sten (13): Tri-n-butylphosphane (0.140 mL, 0.570 mmol) was added
under argon to a solution of thiaphosphirane complex 11a (0.280 g,
0.38 mmol) in dry dichloromethane (10 mL). The color of the solu-
tion changed immediately from yellow to orange. Complete conver-
sion of 11a into 13 within 1 min was indicated by 31P NMR spec-
troscopy. Owing to the extreme sensitivity of 13 to oxygen, purifica-
IR (KBr): ν = 2073 (s), 1936 (vs), 1489 (m), 1444 (m), 1262 (m),
˜
1103 (m), 1032 (m), 743 (m), 696 (m) cm–1. 1H NMR: δ = 5.99 (dd,
3
3JH,H = 8.2, 1.1 Hz, 2 H, o-3-PhH), 6.72 (t, JH,H = 7.7 Hz, 2 H,
m-3-PhH), 6.86 (t, 3JH,H = 7.5 Hz, 1 H, p-3-PhH), 7.12 (m, 3 H, 4-
H, o-5-PhH), 7.20 (m, 2 H, 6-HFluo, p-5-PhH), 7.23–7.30 (m, 6 H,
7-HFluo, m/p-6-PhЈH, m-5-PhH), 7.41 (m, 4 H, 2-HFluo, m/p-6-
1
3
tion was not possible. H NMR: δ = 6.82 (d, JH,H = 7.5 Hz, 2 H,
o-3Ј-PhH), 7.04 (m, 3 H, m/p-3Ј-PhH), 7.16 (d, JH,H = 7.5 Hz, 2
3
3
PhH), 7.54 (dt, JH,H = 7.5, 1.4 Hz, 1 H, 3-HFluo), 7.59 (d, JH,H
=
3
7.3 Hz, 2 H, o-6-PhЈH), 7.64 (d, 3JH,H = 7.6 Hz, 1 H, 5-HFluo), 7.79
H, 1-HFluo, 8-HFluo), 7.19 (m, 1 H, 2-HFluo or 7-HFluo), 7.23 (t,
3
(m, 3 H, 4-HFluo, o-6-PhH), 7.88 (dd, JH,H = 7.7, 2.7 Hz, 1 H, 8-
3JH,H = 7.4 Hz, 1 H, 2-HFluo or 7-HFluo), 7.45 (t, JH,H = 7.4 Hz,
3
HFluo), 8.28 (dd, 3JH,H = 7.6, 2.8 Hz, 1 H, 1-HFluo) ppm. 13C NMR:
3
3 H, m/p-5Ј-PhH), 7.51 (t, JH,H = 7.6 Hz, 2 H, 3-HFluo, 6-HFluo),
7.77 (dd, JH,H = 7.4, 1.4 Hz, 2 H, o-5Ј-PhH), 7.91 (d, JH,H
7.7 Hz, 2 H, 4-HFluo, 5-HFluo), 7.96 (d, JP,H = 19.8 Hz, 1 H, 4Ј-
H) ppm. 31P NMR: δ = 233.6 (1JP,W = 275.6 Hz) ppm. MS (CI,
100 eV): m/z (%) = 711 (13) [MH]+.
δ = 59.2 (d, 1JP,C = 2.9 Hz, C-2), 71.3 (d, JP,C = 2.2 Hz, C-5), 89.9
2
3
3
=
2
(d, JP,C = 2.9 Hz, C-6), 120.8, 125.3, 126.6, 126.9, 127.0, 127.1,
3
127.3, 127.4, 127.6, 127.8, 128.1, 128.2, 128.3, 128.4, 128.4, 128.7,
128.9, 129.0, 129.0, 129.4, 129.6, 129.7, 130.1, 131.0, 132.0, 132.4,
3
136.1 (d, JP,C = 5.1 Hz, C-4), 137.6, 138.1, 139.4, 141.7, 141.9,
2
Sulfuration of 2H-Phosphole 13: An excess of elemental sulfur 142.6, 142.9, 143.0, 143.2, 143.5, 194.0 (d, JP,C = 6.6 Hz, COeq),
2
(60.8 mg, 1.90 mmol) was added to a solution of freshly prepared
2H-phosphole 13 (see above) in dichloromethane (10 mL). Thia-
phosphirane 11a was formed quantitatively. 31P NMR: δ = –6.4
(1JP,W = 291.6 Hz) ppm.
197.9 (d, JP,C = 33.7 Hz, COax) ppm. 31P NMR: δ = 52.3 (1JP,W
=
271.0 Hz) ppm. MS (ESI): m/z = 979 [M +K]+, 963 [M + Na]+.
C46H29O5PS2W (940.7): calcd. C 58.73, H 3.11; found C 58.50, H
3.13.
3-(9H-Fluoren-9-ylidene)-1,3-diphenylpropan-1-one (14): Exposure
to air of a freshly prepared solution (see above) of 2H-phosphole
13 in dichloromethane (10 mL) led to the fast disappearance
(Ͻ1 min) of the orange color of the reaction mixture. The solvent
was removed in vacuo and the residue was purified by chromatog-
raphy over silica gel with toluene/cyclohexane (1:1) to yield 14 as
a colorless solid (0.170 g, 80%), m.p. 199 °C (lit.:[35] 204–205 °C).
3,5,6,6-Tetraphenylspiro[7,8-dithia-1-phosphabicyclo[3.2.1]oct-3-ene-
2,9Ј-fluorene] (19): A solution of 7a (45.1 mg, 0.110 mmol) and
thiobenzophenone (42.6 mg, 0.210 mmol) in toluene (10 mL) was
stirred at ambient temperature. After 3 h, the solvent was removed
at 0.05 mbar/20 °C. The crude product was purified by chromatog-
raphy over silica gel with toluene/cyclohexane (1:1). Subsequent
recrystallization from dichloromethane/n-pentane at 0 °C gave 19
as a pale-yellow solid (63.0 mg, 93%), m.p. 151 °C (dec.). IR (KBr):
IR (KBr): ν = 1687 (vs, C=O), 1594 (m), 1446 (s), 1420 (m), 1322
˜
(m), 1300 (m), 1262 (m), 1209 (s), 804 (m), 780 (s), 729 (vs), 696 ν = 1596 (m), 1491 (s), 1442 (s), 1035 (m), 761 (m), 738 (vs), 697
˜
3
(s) cm–1. 1H NMR: δ = 4.84 (s, 2 H, CH2), 6.23 (d, 3JH,H = 8.0 Hz,
(vs) cm–1. 1H NMR: δ = 6.11 (dd, JH,H = 8.3, 1.0 Hz, 2 H, o-3-
3
3
3
3
1 H, 8-HFluo), 6.86 (t, JH,H = 7.7 Hz, 1 H, 7-HFluo), 7.17 (t, JH,H
PhH), 6.76 (t, JH,H = 7.7 Hz, 2 H, m-3-PhH), 6.88 (t, JH,H =
7.3 Hz, 1 H, p-3-PhH), 7.12 (d, JP,H = 3.3 Hz, 1 H, 4-H), 7.14–
7.29 (m, 10 H, 6-HFluo, 7-HFluo, HPh), 7.30 (t, JH,H = 8.2 Hz, 1 H,
= 7.5 Hz, 1 H, 2-HFluo), 7.20 (t, 3JH,H = 7.4 Hz, 1 H, 6-HFluo), 7.33
4
3
3
3
(dt, JH,H = 7.6, 0.6 Hz, 1 H, p-3-PhH), 7.38 (t, JH,H = 7.2 Hz, 1
H, 6-HFluo), 7.40–7.52 (m, 5 H, m-1-PhH, m-3-PhH, 1-HFluo), 7.53
3
3-HFluo), 7.40 (m, 4 H, 2-HFluo, m/p-6-PhH), 7.51 (t, JH,H
=
(d, JH,H = 7.5 Hz, 1 H, o-3-PhH), 7.60 (t, JH,H = 7.4 Hz, 1 H, p- 7.5 Hz, 1 H, HPh), 7.54 (m, 2 H, o-6-PhЈH), 7.59 (d, 3JH,H = 7.6 Hz,
3
3
3
1-PhH), 7.67 (m, 2 H, 5-HFluo, o-3-PhH), 7.75 (d, JH,H = 7.7 Hz,
1 H, 5-HFluo), 7.76 (d, 3JH,H = 7.6 Hz, 1 H, 8-HFluo), 7.85 (m, 3 H,
1 H, 4-HFluo), 8.04 (m, 2 H, o-1-PhH) ppm. 13C NMR: δ = 48.5 4-HFluo, o-6-PhH), 8.14 (dd, JH,H = 7.3, 2.0 Hz, 1 H, 1-
3
1
(CH2), 119.1 (CFluo-5), 119.7 (CFluo-4), 120.3 (m-3-Ph), 124.1
HFluo) ppm. 13C NMR: δ = 55.7 (d, JP,C = 41.7 Hz, C-2), 68.9 (d,
(CFluo-1), 124.2 (o-3-Ph), 125.0 (CFluo-8), 126.6 (CFluo-7), 127.1 1JP,C = 3.7 Hz, C-5), 85.7 (d, JP,C = 5.1 Hz, C-6), 120.3, 120.5,
2
(CFluo-2), 127.4 (CFluo-6), 127.8 (CFluo-3), 127.9 (o-3-Ph), 128.1 (o- 125.3, 126.3, 126.7, 126.8, 126.9, 127.1, 127.2, 127.3, 127.5, 127.6,
Eur. J. Org. Chem. 2009, 2195–2207
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
2205

S. Maurer, T. Jikyo, G. Maas
Table 2. Crystallographic data and details of data collection and structure refinement for 6a, 7a, 11a and 12a.[a]
FULL PAPER
7a
8a
11a
12a
Empirical formula
Formula weight
Temperature [K]
Crystal size [mm]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
α [°]
C28H19PS
418.46
193(2)
0.46ϫ0.19ϫ0.08
monoclinic
P21/n
11.1464(11)
9.7308(7)
19.417(2)
90
C28H21OPS
436.48
190(2)
0.38ϫ0.38ϫ0.31
monoclinic
C2/c
17.638(2)
21.645(3)
11.8739(14)
90
C33H19O5PSW
742.36
193(2)
0.58ϫ0.31ϫ0.19
tetragonal
I41/a
33.046(2)
33.046(2)
10.3660(6)
90
C61H39O5PS2W
1130.86
190(2)
0.38ϫ0.27ϫ0.15
monoclinic
P21/c
12.8398(12)
18.3062(18)
20.531(2)
90
β [°]
101.290(12)
90
2065.3(3)
4
1.346
0.247
105.857(13)
90
4360.5(9)
8
1.330
0.240
90
90
99.202(12)
90
4763.7(8)
4
1.577
2.600
γ [°]
Volume [Å3]
11320.1(12)
16
1.742
4.254
5792
Z
Density [gcm–3]
µ(Mo-Kα) [mm–1]
F(000)
872
1824
2264
θ range [°]
2.14–26.00
15858
3865 (0.0574)
95.4
–
–
3865/0/347
0.855
0.0315, 0.0639
0.0590, 0.0698
0.20, –0.21
2.08–24.71
15178
3546 (0.1585)
95.2
–
–
3546/0/280
0.851
0.0569, 0.1395
0.0971, 0.1542
0.30, –0.29
2.06–25.96
54812
5316 (0.0674)
95.9
empirical
0.446/0.200
5316/0/370
1.069
0.0245, 0.0558
0.0336, 0.0621
0.48, –0.57
2.01–25.88
37383
8694 (0.0746)
94.0
numerical
0.7115/0.5134
8694/0/631
0.893
0.0376, 0.0998
0.0588, 0.1032
0.84, –0.94
Reflections collected
Independent reflections (Rint
Completeness to θmax [%]
Absorption correction
Max./min. transmission
Data/restraints/parameters[b]
Goodness-of-fit on F2
)
Final R indices [IϾ2σ(I)]:[b] R1, wR2
R indices (all data):[c] R1, wR2
Largest diff. peak and hole [eÅ–3]
[a] CCDC-713424 (for 7a), -713425 (for 11a), -713426 (for 12a), and -713427 (for 8a) contain the supplementary crystallographic 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. [b] Refinement based on F2 values. [c] R1 = Σ|Fo| – |Fc|/Σ|Fo|; wR2 = {Σ[w(Fo – Fc ) ]/Σw(Fo2)2} .
2
2 2
½
[2]
[3]
[4]
[5]
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1207–1212.
N. Mézailles, P. E. Fanwick, C. P. Kubiak, Organometallics
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127.7, 127.8, 127.9, 128.1, 128.2, 128.4, 128.9, 129.0, 129.6, 130.0,
131.3, 131.8, 132.0, 137.4, 139.6, 140.4, 141.0, 142.4, 142.5, 144.3,
144.5, 145.7, 147.3 ppm. 31P NMR: δ = 26.9 ppm. MS (CI, 100 eV):
m/z (%) = 617 (Ͻ1) [MH]+, 419 (6) [M – Ph2CS + 1]+, 199 (100)
[Ph2CS + 1]+. C41H29PS2 (616.8): calcd. C 79.84, H 4.74; found C
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pectation, this phosphirane is a relatively good electron donor,
whereas its electron-accepting ability does not differ signifi-
Crystal Structure Determinations: Data collection was performed
on an image-plate diffractometer (Stoe IPDS) using monochro-
mated Mo-Kα radiation (λ = 0.71073 Å). The structures were
solved by direct methods and refined by using a full-matrix least-
squares method. Hydrogen atoms in 7a were located on a ∆F map
and were included in the refinement. In all other cases, they were
calculated geometrically and treated as riding atoms on their bond
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SHELX-97;[36] molecule plots: ORTEP-3.[37] Further details are
provided in Table 2.
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Acknowledgments
S. M. thanks the Fonds der Chemischen Industrie for a scholarship.
T. J. thanks the Alexander von Humboldt foundation for a fellow-
ship.
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www.eurjoc.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Received: January 2, 2009
Published Online: March 19, 2009
Eur. J. Org. Chem. 2009, 2195–2207
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
2207