Partial ring-opening and rearrangement reactions of P,C-cages to yield unusual phosphinous acids stabilized by pentacarbonyltungsten

Article abstract of DOI:10.1021/om9009334

First reactions of polycyclic phosphirane complexes 3a-c are reported that include lithium hydroxide induced partial ring-opening and rearrangement reactions to give new tricyclic phosphinous acid complexes 4-7 as final products. Besides multinuclear NMR and IR spectroscopy and mass spectrometry, the molecular structures of complexes 4-6 were established by single-crystal X-ray crystallography.

Full text of DOI:10.1021/om9009334

656 Organometallics 2010, 29, 656–661
DOI: 10.1021/om9009334
Partial Ring-Opening and Rearrangement Reactions of P,C-Cages to
Yield Unusual Phosphinous Acids Stabilized by Pentacarbonyltungsten
†
†
†
‡
€
Maren Bode, Gregor Schnakenburg, Jorg Daniels, Angela Marinetti, and
Rainer Streubel*,†
†Institut fu€r Anorganische Chemie, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany and ‡Institut de
Chimie des Substances Naturelles, 1 Avenue de la Terrasse, 91198 Gif-su^r-Yvette Cedex, France
Received October 23, 2009
First reactions of polycyclic phosphirane complexes 3a-c are reported that include lithium
hydroxide induced partial ring-opening and rearrangement reactions to give new tricyclic phosphi-
nous acid complexes 4-7 as final products. Besides multinuclear NMR and IR spectroscopy and
mass spectrometry, the molecular structures of complexes 4-6 were established by single-crystal
X-ray crystallography.
Introduction
behave. Another special point of interest to study polycyclic
phosphirane derivatives derives from their rigid geometry,
chirality that might especially suit their uses as chiral aux-
iliaries, and small Tolman angles6 of such ligands; in some
cases a surprising chemical inertness of the phosphorus
center, i.e., toward hydrolysis and oxidation, was observed.7
Unfortunately, the synthesis of polycyclic phosphiranes
usually requires complicated multistep reaction sequences,
and therefore P,C-cage structures and substitution patterns
are very much restricted. In consequence, and with some
exceptions,8,9 the knowledge about the chemistry of P,C-
cage derivatives is comparatively scarce. Here, we present the
synthesis of sterically encumbered tetracyclic P,C-cage li-
gands using an optimized protocol and first results of reac-
tions of the phosphirane subunit with lithium hydroxide.
Although phosphiranes have been known since 1963,1
studies on their reactivity were comparatively rare until the
early 1990s. Since then several synthetic applications were
developed such as cationic ring-opening polymerization,
providing access to new polymers containing trivalent phos-
phorus.2 Furthermore, theoretical studies also revealed pos-
sible applicability in radical ring-opening polymerization.3
Anionic ring-opening polymerization presents a more com-
plicated overall picture,4 as attack at the carbon center of the
phosphirane unit appears to be feasible, although nucleo-
philic attack at phosphorus may effectively compete as
indicated by the polarization of Pδþ-Cδ- bonds.
The preferential nucleophilic attack at phosphorus has
been demonstrated experimentally in reactions of phosphir-
ane tungsten complexes I with nucleophiles, although diver-
gent outcomes had been observed for these reactions.5 Here,
nucleophilic attack usually followed one of the two following
reaction pathways, assuming that transient species II with a
five-coordinated phosphorus center were involved: (1) loss of
an alkene derivative and formation of phosphanide com-
plexes III or (2) ring-opening of II to give carbanionic
complexes IV (Scheme 1). In the latter case, the carbanionic
center in IV then subsequently reacted with either a proton
source or a CO group of the pentacarbonyltungsten frag-
ment.5
Experimental Results
Tetracyclic P,C-cage tungsten complexes 3a-c were obtained
via thermolysis of P-C5Me5-substituted 2H-azaphosphirene
tungsten complex 110 in toluene in the presence of alkynyl esters.
31P NMR spectroscopic reaction monitoring revealed that the
formation of the polycyclic phosphirane derivatives 3a,11b,c12
proceeded via intramolecular [4þ2] cycloaddition reactions of
transient 1H-phosphirene tungsten complexes 2a-c (Scheme 2).
31P{1H} NMR chemical shifts of the “closed” P,C-cage com-
plexes 3a-c are between -70 and -90 ppm and show a notable
influence of the substituents at the R-carbon atoms. A typical
1
All studies hitherto described were conducted using mono-
cyclic phosphiranes, so that the quest is still open on how P,
C-cage compounds having a phosphirane subunit would
feature of these complexes are the J(W,P) coupling constant
(6) Tolman, C. A. Chem. Rev. 1977, 77, 313.
(7) Liedtke, J.; Loss, S.; Alcaraz, G.; Gramlich, V.; Grutzmacher, H.
€
*Corresponding author. E-mail: r.streubel@uni-bonn.de.
(1) Wagner, R. I. U.S. patents 3 086 053 and 3 086 056, 1963. Wagner,
R. I.; Freeman, L. D.; Goldwhite, H.; Rowsell, D. G. J. Am. Chem. Soc.
1967, 89, 1102.
(2) Kobayashi, S.; Kadokawa, J.-I. Macromol. Rapid Commun. 1994,
15, 567.
(3) Coote, M. L.; Hodgson, J. L. Macromolecules 2005, 38, 8902.
(4) Coote, M. L.; Hodgson, J. L.; Krenske, E. H.; Wild, S. B.
Heteroat. Chem. 2007, 18, 118. Coote, M. L.; Krenske, E. H.; Maulana,
I.; Steinbach, J.; Wild, S. B. Heteroat. Chem. 2008, 19, 178.
(5) Marinetti, A.; Mathey, F. Tetrahedron 1989, 45, 3061.
Angew. Chem., Int. Ed. 1999, 38, 1623.
(8) Hofmann, M.; Hohn, C.; Heinemann, F. W.; Zenneck, U.
Chem.;Eur. J. 2009, 15, 5998.
(9) Panhans, J.; Heinemann, F. W.; Zenneck, U. J. Organomet.
Chem. 2009, 694, 1223.
(10) Streubel, R.; Rhode, U.; Jeske, J.; Ruthe, F.; Jones, P. G. Eur. J.
Inorg. Chem. 1998, 2005.
(11) Streubel, R.; Bode, M.; Frantzius, G. v.; Hrib, C.; Jones, P. G.;
Monsees, A. Organometallics 2007, 26, 1371.
(12) Rhode, U.; Ruthe, F.; Jones, P. G.; Streubel, R. Angew. Chem.,
Int. Ed. 1999, 38, 215.
€
r
pubs.acs.org/Organometallics
Published on Web 01/07/2010
2010 American Chemical Society

Article
Organometallics, Vol. 29, No. 3, 2010 657
Scheme 1. Reactions of Phosphirane Complexes I with Nucleophiles5
Scheme 2. Synthesis of P,C-Cage Complexes 3a,11b,c12
Table 1. Selected NMR Spectroscopic Data of P,C-Cage Complexes 3a,11b,c12
magnitudes of about 230-241 Hz as well as comparatively large
|1J(P,C)| values for C5 centers (cf. Table 1).
gave the partially cage-opened complex 4 (Scheme 3, Figure 4).
Reactions of complexes 3b,c followed a more complicated
course, selectively yielding 5 in the case of 3b or a mixture of 6
and a not fully identified compound 7 (ratio: 1.3:1) in the case of
3c; formation of 5 and 6 evidently involved rearrangement
reactions. Complexes 5 and 6 were structurally confirmed by
single-crystal X-ray structures (Figure 5 and 6), both revealing
the P-OH function. On the basis of the NMR spectroscopic and
mass spectrometric data we concluded that complex 7 is most
probably an isomer of complex 6 possessing also a P-OH
function (δ 1H = 4.25 (|J(P,H)| = 1.9 Hz)).
X-ray crystallography (Figures 1, 2 and ref 12) revealed that
the cage structure is not significantly influenced by the different
substituents on the phosphirane ring, so that bond lengths and
angles observed in the cage are identical within the margins of
error; although some bonds in the more congested derivative 3b
˚
appeartobemarginallylonger(3b: e.g., P-W:2.464(1) A; P-C4:
˚
˚
˚
1.844(3) A) thanin3a (P-W: 2.455(2) A; P-C4: 1.839(7) A) or3c
˚
˚
(P-W: 2.457(8) A; P-C4: 1.836(3) A). Typical structural fea-
tures of these cage structures are small bond angle sums at
phosphorus ( — P(PR3)) of 195ꢀ (3a and 3c) or 196ꢀ (3b), thus
P
The formation of products 4-7 is remarkable, as only very
few examples of cyclic diorganyl-phosphinous acid complexes
can be found in the literature (Figure 3).14-19 They are usually
obtained by substitution at phosphorus14,15 or hydrolysis of a
yielding a strained, rigid cage that possesses a long P-C1 bond of
1.908(7) A (3a), 1.916(3) A (3b), or 1.924(3) (3c ); for compar-
12
˚
˚
ison, typical P(III)-Csp3 bond lengths are around 1.855 A.
13
˚
Reaction of the polycyclic phosphirane tungsten complex 3a,
bearing a proton and a C-ester group at the phosphirane ring-
carbons, with lithium hydroxide and subsequent protonation
(14) Borst, M. L. G.; Bulo, R. E.; Gibney, D. J.; Alem, Y.; de Kanter,
F. J. J.; Ehlers, A. W.; Schakel, M.; Lutz, M.; Spek, A. L.; Lammertsma,
K. J. Am. Chem. Soc. 2005, 127, 16985.
(15) Holand, S.; Mathey, F. Organometallics 1988, 7, 1796.
(16) Sierra, M. L.; Maigrot, N.; Charrier, C.; Ricard, L.; Mathey, F.
Organometallics 1991, 10, 2835.
(13) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen,
A. G.; Taylor, R. J. Chem. Soc., Perkin Trans. 2 1987, S1.

658 Organometallics, Vol. 29, No. 3, 2010
Scheme 3. Reactions of P,C-Cage Complexes 3a-c with Lithium Hydroxide
Bode et al.
Table 2. Selected NMR Spectroscopic Data of P,C-Cage
Complexes 4-6
Figure 2. Molecular structure of 3b in the crystal (thermal
ellipsoids at 50% probability level; H atoms are omitted for
˚
clarity). Selected bond length [A] and angles [deg]: P-W
2.464(8), P-C3 1.827(3), P-C4 1.844(3), P-C1 1.916(3),
P
C3-C4 1.560(4), C3-P-C4 50.3 (1), —P(PR3) 196 ((2)ꢀ.
double bond16,17 often during column chromatography. Only in
the case of phosphorine complex 13 did the P-OH function
result from a planned nucleophilic attack of the hydroxide at
phosphorus in the corresponding phosphinine complex. As non-
ligated diorganylphosphinous acids (R2POH) usually rearrange to
the corresponding pentavalent secondary phosphine-oxides
(R2P(O)H),20,21 most known diorganylphosphinous acids are
stabilized by transition metal complexation, as first reported by
Chatt in 1968.22 It is noteworthy that due to the air- and moisture-
(17) Le Floch, P.; Carmichael, D.; Mathey, F. Organometallics 1991,
10, 2432.
(18) Le Floch, P.; Ricard, L.; Mathey, F. Polyhedron 1990, 9, 991.
(19) Alonso, M.; Alvarez, M. A.; Garcia, M. E.; Ruiz, M. A.;
Hamidov, H.; Jeffery, J. C. J. Am. Chem. Soc. 2005, 127, 15012.
(20) Hoge, B.; Bader, J.; Beckers, H.; Kim, Y. S.; Eujen, R.; Willner,
H.; Ignatiev, N. Chem.;Eur. J. 2009, 15, 3567.
(21) Some stabilization can be achieved by introduction of strongly
electron-withdrawing groups such as CF3; B. Hoge et al.20 showed that
in some cases RF2POH are more stable than RF2P(H)O.
(22) Chatt, J.; Heaton, B. T. J. Chem. Soc. A 1968, 2745.
Figure 1. Molecular structure of one independent molecule of
3a11 in the crystal (thermal ellipsoids at 50% probability level; H
atoms (except H3a) are omitted for clarity). As the values for the
second independent molecule of the unit cell do not deviate
significantly from the one displayed here, it is neither displayed
nor discussed (see Supporting Information). Selected bond
˚
length [A] and angles [deg]: P1-W1 2.455(2), P-C3 1.829(7),
P-C4 1.839(7), P-C1 1.908(7), C3-C4 1.549(10), C3-P-C4
P
50.0 (3), —P(PR3) 195 ((2)ꢀ.

Article
Organometallics, Vol. 29, No. 3, 2010 659
Figure 3. Examples of cyclic diorganylphosphinous acid complexes.14-19
Figure 6. Molecular structure of 6 CDCl3 in the crystal
3
Figure 4. Molecular structure of 4 in the crystal (thermal ellip-
soids at 50% probability level; H atoms (except H1, H11, and
˚
H12) are omitted for clarity). Selected bond length [A] and
(thermal ellipsoids at 50% probability level; H atoms (except
˚
H1 and Ho5) are omitted for clarity). Selected bond length [A]
and angles [deg]: P-W 2.497 (1), P-O5 1.616 (2), P-C1 1.854
angles [deg]: P-W 2.540 (1), P-O1 1.610 (4), P-C1 1.846 (5),
(2), P-C7 1.873 (2), C1-C2 1.524(3), C1-P-C7 90.4 (1),
P
P-C11 1.880 (5), C11-C12 1.530 (7), C1-P-C11 71.9 (2),
—P(PR3) 296((2)ꢀ.
P
—P(PR3) 280((2)ꢀ.
The products 4-7 display considerably downfield shifted
31P{1H} resonances, thus reflecting the conversion of a three-
into a four- (4) or five-membered phosphorus heterocycle (5, 6)
and the presence of a P-OH group. This is accompanied by an
increase of the 1J(W,P) coupling constant magnitude (253-273 Hz)
and a decrease of |1J(P,C)| values, as in complex 4, which
displays a 1J(P,C5) = 17.8, vs 33 Hz in 3a.
As expected the partially opened and rearranged polycyclic
P
ligands in 4-6 (Figures 4-6) have notably larger — P(PR3)
values, especially the C-phenyl-substituted derivative 5 (306ꢀ
compared to 196ꢀ in the closed cage complex 3b). Striking is that
˚
significantly longer W-P bonds were observed (2.532(1) A in 5
˚
vs 2.464(8) A in 3b), although bonding of phosphorus to the OH
group usually shortens all and every other bond (to phos-
phorus). Compared to the only other structurally characterized
cyclic diorganylphosphinous acid, 1419 (Figure 3), complexes
˚
4-6 exhibit comparable P-O bond lengths around 1.61 A and
Figure 5. Molecular structure of 5 in the crystal (thermal ellip-
soids at 50% probability level; H atoms (except H1 and H1a) are
˚
omitted for clarity). Selected bond length [A] and angles [deg]:
˚
˚
slightly longer P-C bond lengths (1.84 A (14) and 1.85-1.89 A
in 4-6) most probably due to the different ring systems and
substitution patterns involved.
P-W 2.532 (1), P-O1 1.597 (2), P-C1 1.870 (3), P-C7 1.885
P
(3), C1-C2 1.533(4), C1-P-C7 90.0 (1), —P(PR3) 306((2)ꢀ.
Conclusions
stability of the preligands, phosphinous acid complexes have found
applications in transition-metal-catalyzed transformations,23
hinting also at potentially interesting uses of ligands 4-7.
First investigations on the reactivity of various poly-
cyclic phosphirane complexes toward lithium hydroxide
showed partial ring-opening and formation of new
cyclic phosphinous acid complexes. Here a significant
(23) Ackermann, L. Synthesis 2006, 10, 1557.

660 Organometallics, Vol. 29, No. 3, 2010
Bode et al.
dependence of the reaction pathway on the substitution
pattern was observed, as either cleavage of the P-C bond
or isomerization leading to complexes with semibullva-
lene-type structures 5 (reaction of 3b) and 6 (reaction of
3c) was observed. Nucleophilic attack of the hydroxide at
the phosphorus atom can be assumed as the first step
followed by the cleavage of one of the phosphirane P-C
bonds. The quest for nucleophilic bond cleavage of non-
ligated polycyclic phosphiranes remains open for future in-
vestigations.
3J(P,H) = 19 Hz). MS (EI, 70 eV): m/z 664 [M•þ, 73]. FTIR (KBr;
ν(CO)): ν~ 2077 (m), 1998 (m), 1956 (s, shoulder), 1939 (s), 1927(s),
1920 (s, shoulder), 1712 (m) [cm-1]. Anal. Calcd: C 47.01, H 3.79.
Exptl: C 46.92, H 4.08. X-ray crystallographic analysis: Suitable
colorless single crystals were obtained from concentrated n-pen-
tane solutions upon cooling to 4 ꢀC; C26H25O7PW; crystal size
3
˚
0.56 ꢀ 0.32 ꢀ 0.16 mm , monoclinic, C2/c, a = 32.9185(12) A,
˚
˚
b= 8.9633(2) A,c= 20.9422(8) A,R=90ꢀ,β= 120.6280(13)ꢀ,γ=
3
˚
90ꢀ, V = 5317.1(3) A , Z = 8, 2θmax = 58ꢀ, collected (independent)
reflections = 22 141 (6972), Rint = 0.0545, μ = 4.446 mm-1, 6
restraints, 331 refined parameters, R1 (for I > 2σ(I)) = 0.0296,
wR2 (for all data) = 0.0657, max./min. residual electron density =
3
˚
1.681/-2.143 e A .
Experimental Section
Reaction of 3a-c. To a solution of 4-phosphatetracyclo-
[3.3.0.02,4.03,6]oct-7-ene complex (3a-c) in THF was added
absolute ethanol, and the reaction mixture was cooled to 0 ꢀC.
Then a solution of lithium hydroxide monohydrate in distilled
water was added dropwise. The reaction mixture was stirred at
0 ꢀC for 3 h and then at rt for another 12 h. Using a 1 M solution
of potassium hydrogensulfate the mixture was brought to pH 3,
and then THF was removed in vacuo. The reaction mixtures
were extracted with ethyl acetate (2ꢀ) and dichloromethane.
The joined organic phases were washed with brine and then
dried using magnesium sulfate. The solvents were evaporated,
and the raw products were obtained as yellow paste-like resi-
dues, which were washed with n-pentane (4, 5) or purified by
low-temperature column chromatography (6/7).
General Procedures. All operations were performed in an
atmosphere of purified and dried argon. Solvents were distilled
from sodium. NMR data were recorded on a Bruker Avance 300
spectrometer at 30 ꢀC using CDCl3 as solvent and internal
standard; shifts are given relative to tetramethylsilane (1H:
300.1 MHz; 13C: 75.5 MHz) and 85% H3PO4 (31P: 121.5 MHz)
in ppm. Mass spectra were recorded on a Kratos MS 50 spectro-
meter (EI, 70 eV); only m/z values are given. Elemental analyses
were performed using an Elementa (Vario EL) analytical gas
chromatograph. Infrared spectra were collected on a Nicolet
€
380 FT-IR. Melting points were obtained on a Buchi 535
capillary apparatus. X-ray crystallographic analysis of 3a,b,
4-6: Data were collected on a Nonius KappaCCD diffract-
˚
ometer at 123 K using Mo KR radiation (λ = 0.71073 A). The
4: white solid, mp 115 ꢀC. Yield: 132 mg (46.0%). Selected
structure was refined by full-matrix least-squares on F2
(SHELXL-9724). All non-hydrogens were refined anisotropi-
cally. The hydrogen atoms were included in calculated positions
using a riding model.
data: 1H NMR: 0.95 (d, J(P,H) = 13.4 Hz, 3H, Ccage-C5-CH3),
1.26 (t, J(H,H) = 7.1 Hz, 3H, CH2CH3), 1.44 (s, 3H, Ccage
-
CH3), 1.51 (s, 3H, Ccage-CH3), 1.74 (d, J(P,H) = 1.2 Hz, 3H,
Ccage-CH3), 1.78 (m, 3H, Ccage-CH3), 2.14 (dd, J(P,H) =
43.3 Hz, J(H,H) = 4.4 Hz, 1H, PCH), 2.41 (br s, 1H, OH),
2.97 (ps. “t”(= dd), J ≈ 4 Hz), J(H,H) = 4.4 Hz, 1H, PCH-
C(H)CO2Et), 4.20 (dq, J(H,H) = 11.1 Hz, J(H,H) = 7.2 Hz,
X-ray Crystallographic Analysis of 3a. Suitable pale yellow
single crystals were obtained from concentrated n-pentane solu-
tions upon cooling to 4 ꢀC; C20H21O7PW; crystal size 0.32 ꢀ
3
˚
˚
2H, OCH2). 13C{1H} NMR: δ 4.8 (d, J(P,C) = 2.9 Hz, Ccage
-
0.32 ꢀ 0.16 mm , triclinic, P1, a= 10.7147(5) A, b= 13.2996(5) A,
˚
CH3), 8.9 (d, J(P,C) = 1.6 Hz, Ccage-CH3), 10.7 (s, Ccage-CH3),
11.7 (d, J(P,C) = 1.0 Hz, Ccage-CH3), 12.9 (s, CH2CH3), 14.7 (d,
c = 16.8471(5) A, R= 75.655(2)ꢀ, β= 83.494(2)ꢀ, γ= 70.934(2)ꢀ,
3
˚
V = 2196.92(15) A , Z = 4, 2θmax = 56ꢀ, collected (independent)
reflections = 27 583 (10 518), Rint = 0.1322, μ = 5.368 mm-1
,
J(P,C) = 0.6 Hz, Ccage-CH3), 52.1 (d, J(P,C) = 24.9 Hz, Ccage
-
C3), 53.1 (d, J(P,C) = 12.3 Hz, Ccage-C2), 56.8 (d, J(P,C) = 17.8
Hz, Ccage-C5), 59.9 (s, Et-CH2), 67.4 (d, J(P,C) = 11.6 Hz, Ccage
536 refined parameters, R1 (for I > 2σ(I)) = 0.0528, wR2 (for all
data) = 0.1282, max./min. residual electron density = 2.707/
˚
-
3
C1/6), 71.3 (d, J(P,C) = 25.5 Hz, Ccage-C1/6), 133.0 (d, J(P,C) =
10.0 Hz, Ccage-C7/8), 149.5 (d, J(P,C) = 6.5 Hz, Ccage(C7/8),
169.3 (d, J(P,C) = 6.5 Hz, CO2Et), 195.8 (d, J(P,C) = 7.4 Hz,
cis-CO), 197.3 (d, J(P,C) = 28.4 Hz, trans-CO). 31P NMR: δ
-140.2 (dqSat, 1J(W,P) = 253.0 Hz, 1J(P,H) = 43.2 Hz (d), J(P,
H) = 13.4 Hz (q)). MS (EI, 70 eV): m/z 606 [M•þ, 29]. FTIR
(KBr): ν~ 3263 (w, OH), 2974 (w, OH), 2938 (w, OH), 2070 (s,
CO), 1982 (s, CO), 1964 (s, CO), 1936 (s, CO), 1918 (s, shoulder,
CO), 1695 (s, CO) [cm-1]. Anal. Calcd: C 39.63, H 3.82. Exptl: C
39.63, H 4.05. X-ray crystallographic analysis: Suitable pale yellow
single crystals were obtained from concentrated diethyl ether solu-
-3.634 e A .
Synthesis of {Pentacarbonyl[1,5,6,7,8-pentamethyl-2-(ethoxy-
carbonyl)-3-phenyl-4-phosphatetracyclo[3.3.0.02,4.03,6]oct-7-en-
KP]tungsten(0)} (3b). A 0.17 mL (1.0 mmol) amount of ethyl
phenylpropiolate was dissolved in 13 mL of toluene and heated
to 90 ꢀC. Then a solution of 0.50 g (0.84 mmol) of 1 in 62 mL of
toluene was slowly (ca. 10-20 min) added using a dropping
funnel and reflux condenser. The reaction mixture was stirred at
90 ꢀC for another 30 min, and then the solvent was evaporated
and the solid was purified by low-temperature column chroma-
tography to deliver a yellow solid, mp 104 ꢀC. Yield: 137 mg
1
(25.0%). Selected data for 3b: H NMR: δ 0.64 (d, J(P,H) =
tions upon cooling to 4 ꢀC; C20H23O8PW; crystal size 0.20 ꢀ 0.10 ꢀ
19.3 Hz, 3H, Ccage-C5-CH3), 0.67 (t, J(H,H) = 7.1 Hz, 3H,
CH2CH3), 1.36 (s, 3H, Ccage-CH3), 1.56 (s, 3H, Ccage-CH3), 1.65
(s, 3H, Ccage-CH3), 1.94 (s, 3H, Ccage-CH3), 3.71-3.91 (mc,
(J(H,H) = 7.1 Hz(q)), 2H, OCH2), 7.10-7.14 (mc, 2H, Ph),
7.27-7.32 (mc, 3H, Ph). 13C{1H} NMR:δ4.8 (d, J(P,C) =5.8Hz,
Ccage-CH3), 10.9 (s, Ccage-CH3), 11.1 (s, Ccage-CH3), 12.0 (d, J(P,
C) = 2.3 Hz, Ccage-CH3), 12.5 (s, CH2CH3), 13.1 (d, J(P,C) =
3.6 Hz, Ccage-CH3), 52.6 (d, J(P,C) = 6.8 Hz, Ccage), 59.0
(s, OCH2), 63.7 (d, J(P,C) = 34.3 Hz, Ccage), 65.5 (d, J(P,C) =
8.4 Hz, Ccage), 67.6 (d, J(P,C) = 4.8 Hz, Ccage), 72.1 (d, J(P,C) =
5.2 Hz, Ccage), 126.9 (s, Ph), 127.2 (s, Ph (2x)),128.3 (d, J(P,C) =
7.1 Hz, Ph (2x)), 131.9 (s, Ph), 138.8 (d, J(P,C) = 12.6 Hz, Ccage),
142.0 (d, J(P,C) = 10.0 Hz, Ccage), 168.7 (s, CO2), 192.9 (dSat, J(P,
C) = 7.8 Hz, 1J(W,C) = 125.1 Hz, cis-CO), 196.6 (d, J(P,C) =
33.3 Hz, trans-CO). 31PNMR:δ-76.9 (qSat, 1J(W,P) = 232.7Hz,
3
0.08 mm , monoclinic, P21/n, a = 11.4434(3) A, b =14.0714(5) A,
˚
˚
˚
c= 14.2623(5) A, R=90ꢀ,β=101.036(2)ꢀ, γ=90ꢀ, V= 2254.11(13)
3
˚
A , Z = 4, 2θmax=55ꢀ, collected (independent) reflections = 16 661
(5028), Rint = 0.0788, μ = 5.237 mm-1, 272 refined parameters,
R1 (for I > 2σ(I)) = 0.0385, wR2 (for all data) = 0.0960, max./min.
3
˚
residual electron density = 3.231/-3.120 e A .
5: white solid. Yield: 34 mg (41.5%). Selected data: 1H NMR:
0.96 (t, J(H,H) = 7.1 Hz, 3H, Et-CH3), 1.19 (s, 3H, Ccage-CH3),
1.43 (s, 3H, Ccage-CH3), 1.52 (d, J(P,H) = 18.5 Hz, 3H, Ccage
-
C5-CH3), 1.82 (s, 6H, Ccage-CH3), 2.48 (br s, 1H, OH), 3.33 (d,
J(P,H) = 16.3 Hz, 1H, PC-CH), 3.77-4.08 (mc, 2H, OCH2),
7.30 (s, 5H, Ph). 13C{1H} NMR: 10.4 (d, J(P,C) = 1.3 Hz, Ccage
-
CH3), 11.0 (d, J(P,C) = 1.9 Hz, Ccage-CH3), 11.1 (d, J(P,C) =
7.6 Hz, Ccage-CH3), 11.4 (d, J(P,C) = 0.6 Hz, Ccage-CH3), 12.8
(s, Et-CH3), 15.5 (d, J(P,C) = 14.5 Hz, Ccage-CH3), 37.8 (d, J(P,
C) = 18.9 Hz, Ccage), 43.8 (d, J(P,C) = 27.0 Hz, Ccage), 46.9 (d,
J(P,C) = 9.2 Hz, Ccage), 50.7 (d, J(P,C) = 32.2 Hz, Ccage), 59.4
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(24) Sheldrick, G. M. SHELXL-97; Universitat Gottingen, 1997.

Article
Organometallics, Vol. 29, No. 3, 2010 661
Table 3. Reaction Conditions for the Synthesis of 4-7
3: m [mg] LiOH: m [mg] THF: EtOH: H2O:
pale yellow single crystals were obtained from a concentrated
chloroform-d1 solution upon cooling to 4 ꢀC; C21H23O10-
PW CDCl3; crystal size 0.62 ꢀ 0.23 ꢀ 0.17 mm3, monoclinic,
3
R
R0
(n [mmol])
n [mmol]
V [mL] V [mL] V [mL]
3
˚
˚
˚
P21/n, a = 12.0292(4) A, b =18.2659(6) A, c =12.7250(3) A,
3
˚
R = 90ꢀ, β =98.664(2)ꢀ, γ = 90ꢀ, V = 2764.08(14) A , Z=4,
a
b
c
Et
Et Ph
H
276 (0.47)
78 (0.12)
Me CO2Me 594 (0.94)
100 (2.40)
25 (0.60)
200 (4.80)
6
1.5
12
2
0.5
4
1.5
0.4
3
2θmax =55ꢀ, collected (independent) reflections=18 933 (5992),
Rint = 0.0341, μ = 4.578 mm-1, 425 refined parameters, R1 (for
I >2σ(I)) = 0.0194, wR2 (for all data) = 0.0429, max./min.
(s, Et-CH2), 61.4 (d, J(P,C) = 19.2 Hz, Ccage), 126.1 (d, J(P,C) =
3.2Hz, Ph), 127.3(d, J(P,C) = 2.7 Hz, Ph(2ꢀ)), 128.9 (d, J(P,C) =
5.0 Hz, Ph (2x)), 131.5 (d, J(P,C) = 5.3 Hz, Ph), 135.5 (d, J(P,C) =
1.8 Hz, Ccage), 136.9 (d, J(P,C) = 7.3 Hz, Ccage), 168.4
(s, CO2Et), 195.1 (d, J(P,C) = 7.3 Hz, cis-CO), 196.8 (d, J(P,
3
˚
residual electron density = 0.574/-0.843 e A .
7: white solid, mp 132 ꢀC. Yield: 35 mg (5.8%). Selected data:
1H NMR: 1.42 (s, 6H, Ccage-CH3), 1.47 (d, J(P,H) = 19.0 Hz,
3H, Ccage-C1-CH3), 1.55 (dq, J(P,H) = 3.5 Hz, J(H,H) = 1.1 Hz,
3H, Ccage-CH3), 1.60 (dq, J(P,H) = 1.8 Hz, J(H,H) = 1.1 Hz,
3H, Ccage-CH3), 3.72 (s, 3H, OCH3), 3.77 (s, 3H, OCH3), 4.25 (d,
J(P,H) = 1.9 Hz, 1H, OH), 8.03 (d, J(P,H) = 12.4 Hz, 1H,
Ccage-H). 13C{1H} NMR: δ 8.2 (s, Ccage-CH3), 9.4 (d, J(P,C) =
5.5 Hz, Ccage-CH3), 11.1 (s, Ccage-CH3), 11.2 (d, J(P,C) = 2.3 Hz,
Ccage-CH3), 14.5 (d, J(P,C) = 15.8 Hz, Ccage-CH3), 39.9 (d, J(P,
C) = 12.0 Hz, Ccage), 42.2 (d, J(P,C) = 29.7 Hz, CHcage), 49.1 (d,
J(P,C) = 20.4 Hz, Ccage), 50.5 (d, J(P,C) = 4.5 Hz, Ccage), 51.3
(s, OCH3), 51.7 (s, OCH3), 63.2 (d, J(P,C) = 14.5 Hz, Ccage),
134.6 (d, J(P,C) = 5.8 Hz, Ccage), 139.1 (d, J(P,C) = 7.4 Hz,
Ccage), 168.4 (d, J(P,C) = 2.9 Hz, CO2Me), 176.2 (d, J(P,C) =
5.2 Hz, CO2Me), 195.3 (d, J(P,C) = 7.8 Hz, 1J(W,C) = 125.3 Hz,
cis-CO), 197.2 (d, J(P,C) = 28.1 Hz, trans-CO). 31P NMR: δ
155.7 (ps. quintSat, 1J(W,P) = 273.4 Hz, J(P,H) = 15.8 Hz). MS
(EI, 70 eV): m/z 650 [M•þ, 36]. FTIR (KBr): ν~ 3411 (w, OH),
2962 (w, OH), 2071 (m, CO), 1979 (m, CO), 1957 (m, CO), 1942
(s, CO), 1935 (s, CO), 1914 (s, CO), 1894 (m, shoulder, CO), 1712
(s, CO) [cm-1]. Anal. Calcd: C 38.79, H 3.57. Exptl: C 37.94, H
4.69.
C) = 27.2 Hz, trans-CO). 31P NMR: δ 182.1 ((pseudo) quintSat
,
1J(W,P) = 258 Hz, J ≈ 17 Hz (ps. quint)). MS (EI, 70 eV): m/z
682 [M•þ, 34]. FTIR (KBr): ν~ 3168 (w, OH), 2964 (w, OH), 2071
(w, CO), 1990 (w, CO), 1981 (w, CO), 1946 (s, CO), 1927 (s, CO),
1915(s, CO), 1680 (w, CO) [cm-1]. Anal. calcd: C 45.77, H 3.99.
Exptl: C 45.52, H 4.02. X-ray crystallographic analysis: Suitable
pale yellow single crystals were obtained from concentrated
diethyl ether solutions upon cooling to 4 ꢀC; C26H27O8PW;
crystal size 0.30 ꢀ 0.30 ꢀ 0.10 mm3, orthorhombic, P212121, a =
˚
˚
˚
10.2703(2) A, b = 11.9683(2) A, c = 21.9000(6) A, R = 90ꢀ, β =
3
˚
90ꢀ, γ = 90ꢀ, V = 2691.91(10) A , Z = 4, 2θmax = 56ꢀ, collected
(independent) reflections = 20 427 (6421), Rint = 0.0425, μ =
4.396 mm-1, 332 refined parameters, R1 (for I > 2σ(I)) =
0.0245, wR2 (for all data) = 0.0580, max./min. residual electron
3
˚
density = 1.506/-1.372 e A .
6: white solid, mp 171 ꢀC. Yield: 181 mg (29.7%). Selected
data: 1H NMR: δ 1.18 (s, 3H, Ccage-CH3), 1.28 (d, J(P,H) =0.6 Hz,
3H, Ccage-CH3), 1.45 (d, J(P,H) = 20.2 Hz, 3H, Ccage-CH3),
1.72-1.76 (mc, 6H, Ccage-CH3), 3.20 (d, J(P,H) = 14.9 Hz, 1H,
Ccage-H), 3.67 (s, 3H, OCH3), 3.76 (d, J(P,H) = 0.5 Hz, 3H,
OCH3) (OH not detected). 13C{1H} NMR: δ 10.0 (d, J(P,C) =
1.3 Hz, Ccage-CH3), 10.9 (d, J(P,C) = 7.1 Hz, Ccage-CH3), 11.0
(d, J(P,C) = 1.9 Hz, Ccage-CH3), 11.3 (s, Ccage-CH3), 14.8 (d,
J(P,C) = 16.5 Hz, Ccage-CH3), 36.3 (d, J(P,C) = 14.2 Hz, Ccage),
42.9 (d, J(P,C) = 24.2 Hz, Ccage), 46.4 (d, J(P,C) = 7.4 Hz,
Ccage), 50.3 (d, J(P,C) = 23.9 Hz, CHcage), 50.6 (s, OCH3), 51.5
(s, OCH3), 62.0 (d, J(P,C) = 23.6 Hz, Ccage), 132.6 (d, J(P,C) =
5.8 Hz, Ccage), 136.6 (d, J(P,C) = 7.8Hz, Ccage), 167.7 (d, J(P,C) =
1.6 Hz, CO2), 169.3 (d, J(P,C) = 4.8 Hz, CO2), 194.7 (dSat, J(P,
C) = 7.4 Hz, 1J(W,C) = 125.3 Hz, cis-CO), 196.4 (d, J(P,C) =
Acknowledgment. We thank the University of Bonn,
the ICSN/Institut de Chimie des Substances Naturelles
(CNRS), and the COST action CM0802 “PhoSciNet” for
financial support.
Supporting Information Available: CIF files giving X-ray
crystallographic data for 3a, 3b, and 4-6. This material is
available free of charge via the Internet at http://pubs.acs.org.
Crystallographic data of 3a, 3b, and 4-6 have also been
deposited at the Cambridge Crystallographic Data Centre
under the numbers CCDC-751252 (3a), CCDC-751253 (3b),
CCDC-751254 (4), CCDC-751255 (5), and CCDC-751256 (6).
These data can be obtained free of charge from the Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
28.1 Hz, trans-CO). 31P NMR: δ 174.6 ((pseudo) quintSat
,
1J(W,P) = 264.6 Hz, JPH = 19.1 Hz (pseudo quint)). MS (EI,
70 eV): m/z 650 [M•þ, 40]. FTIR (KBr): ν~ 3407 (w, OH), 2962 (w,
OH), 2078 (s, CO), 1998 (m, CO), 1962 (s, shoulder, CO), 1922
(s, CO), 1712 (s, CO) [cm-1]. Anal. Calcd: C 38.79, H 3.57.
Exptl: C 39.15, H 3.91. X-ray crystallographic analysis: Suitable