Preliminary investigation of the [3+2] cycloaddition reactions of 2-alkylidenephosphiranes

Article abstract of DOI:10.1021/om070236c

The 2-alkylidenephosphirane complex 1 reacts with norbornene and dimethyl acetylenedicarboxylate at 100°C in toluene to give the corresponding [3+2] cycloadducts. With norbornene, only the P-C distal bond is involved, whereas with acetylenedicarboxylate,

Full text of DOI:10.1021/om070236c

3614
Organometallics 2007, 26, 3614-3616
Preliminary Investigation of the [3+2] Cycloaddition Reactions of
2-Alkylidenephosphiranes
Ngoc Hoa Tran Huy,*,†,‡ Louis Ricard,† and Franc¸ois Mathey*,‡
Laboratoire “He´te´roe´le´ments et Coordination” UMR CNRS 7653, DCPH, Ecole Polytechnique,
91128 Palaiseau Cedex, France, and UCR-CNRS Joint Research Chemistry Laboratory,
Department of Chemistry, UniVersity of California RiVerside, California 92521-0403
ReceiVed March 12, 2007
Summary: The 2-alkylidenephosphirane complex 1 reacts with
norbornene and dimethyl acetylenedicarboxylate at 100 °C in
toluene to giVe the corresponding [3+2] cycloadducts. With
norbornene, only the P-C distal bond is inVolVed, whereas with
acetylenedicarboxylate, both the P-C distal and proximal bonds
react.
second phosphinidene unit onto their exocyclic CdC double
bond.9 Along the same vein, we decided to investigate their
cycloaddition chemistry. Our preliminary results are reported
hereafter.
Results and Discussion
Our starting product has been the alkylidenephosphirane
pentacarbonyltungsten complex 1 obtained by cycloaddition of
the transient terminal phosphinidene complex [PhP-W(CO)5]
with the appropriate allene following the work of Lam-
mertsma.10 The preferential cleavage of one of the P-C ring
bonds of 1 during the cycloaddition reactions was taken for
granted. They are indeed substantially weaker than the C-C
ring bond. But what about the choice between the distal and
the proximal P-C bond? Since the X-ray crystal structure of 1
as determined by Lammertsma10 showed that the distal bond is
much longer than the proximal bond (1.85(1) vs 1.776(8) Å)
probably due to the strain at the olefinic ring carbon, we felt
that a preferential distal cleavage was likely. The reaction of
the strained and reactive norbornene with 1 gave us a first
answer (eq 1).
Introduction
The high and varied reactivity of alkylidenecyclopropanes
has led to numerous applications of these molecules in organic
synthesis. The most classical methodology based on these
species involves their transition metal-catalyzed [3+2] cycload-
dition reactions with alkenes and alkynes, leading to five-
membered rings.1 However, the scope of their transformations
is much broader, as shown by the recent discovery that they
isomerize into cyclobutenes in the presence of PtCl2 as a
catalyst2 or cycloadd with two molecules of alkynes in the
presence of a nickel catalyst to give seven-membered rings.3
In the organometallic field, their most spectacular reaction is
their conversion into trimethylenemethane complexes.4 All of
this chemistry is under the control of the ring strain and can
be, a priori, transposed with the heteroatomic analogues of
alkylidenecyclopropanes. Until now, however, attention has been
mainly focused on the synthesis of heteroatomic analogues of
the trimethylenemethane complexes with sulfur,5 silicon,6 and
phosphorus.7 In our group, besides the transformation of
alkylidenephosphiranes into η4-1-phosphatrimethylenemethane
complexes,7 we have also studied their ring opening upon
metalation at the ring sp3-carbon8 and the cycloaddition of a
* Corresponding author. E-mail: francois.mathey@ucr.edu.
† Laboratoire “He´te´roe´le´ments et Coordination”.
‡ UCR-CNRS Joint Research Chemistry Laboratory.
(1) Reviews: Binger, P.; Bu¨ch, H. M. Top. Curr. Chem. 1987, 135, 77.
Yamago, S.; Nakamura, E. Org. React. 2002, 61, 1. Binger, P.; Schmidt,
T. In Houben-Weyl; De Meijere, A., Ed.; Thieme: Stuttgart, Germany, 1997;
Vol. E17c, p 2217. Nakamura, I.; Yamamoto, Y. AdV. Synth. Catal. 2002,
344, 111. Brandi, A.; Cicchi, S.; Cordero, F. M.; Goti, A. Chem. ReV. 2003,
103, 1213.
(2) Fu¨rstner, A.; A¨ıssa, C. J. Am. Chem. Soc. 2006, 128, 6306. Shi, M.;
Liu, L.-P.; Tang, J. J. Am. Chem. Soc. 2006, 128, 7430.
(3) Saito, S.; Masuda, M.; Komagawa, S. J. Am. Chem. Soc. 2004, 126,
10540.
(4) Noyori, R.; Nishimura, T.; Takaya, H. J. Chem. Soc., Chem. Commun.
1969, 89. Billups, W. E.; Lin, L.-P.; Gansow, O. A. Angew. Chem., Int.
Ed. Engl. 1972, 11, 637.
(5) Ando, W.; Choi, N.; Kabe, Y. J. Am. Chem. Soc. 1990, 112,
4574.
(6) Ando, W.; Yamamoto, T.; Saso, H.; Kabe, Y. J. Am. Chem. Soc.
1991, 113, 2791. Kabe, Y.; Yamamoto, T.; Ando, W. Organometallics 1994,
13, 4606.
Under palladium catalysis at 100 °C, the reaction proceeds
in high yield and exclusively takes place at the distal P-C bond
as expected. The two most significant data from the 13C NMR
spectrum of 2 are the R ring carbon resonances at 139.82 (1JC-P
) 33.0 Hz) and 56.42 ppm (1JC-P ) 25.5 Hz). The structure
was fully established by X-ray analysis (Figure 1). The exo
junction between the norbornane and the phospholane rings is
not surprising, but the stereochemistry at phosphorus with the
tungsten on the same side as the norbornane bridge was not
expected. That some steric repulsion exists between the bulky
phosphorus ligand and the complexing group is shown by the
fact that the P-W bond is elongated from 2.500(2) in 110 to
2.5444(8) Å in 2.
We also investigated the reaction of 1 with dimethyl
acetylenedicarboxylate. Unexpectedly the reaction gives two
(7) Tran Huy, N. H.; Marinetti, A.; Ricard, L.; Mathey, F. Organome-
tallics 2001, 20, 593.
(8) Tran Huy, N. H.; Ricard, L.; Mathey, F. J. Organomet. Chem. 2001,
617, 748.
(9) Tran Huy, N. H.; Salemkour, R.; Bartes, N.; Ricard, L.; Mathey, F.
Tetrahedron 2002, 58, 7191.
(10) Krill, S.; Wang, B.; Hung, J.-T.; Horan, C. I.; Gray, G. M.;
Lammertsma, K. J. Am. Chem. Soc. 1997, 119, 8432.
10.1021/om070236c CCC: $37.00 © 2007 American Chemical Society
Publication on Web 06/12/2007

Notes
Organometallics, Vol. 26, No. 14, 2007 3615
(8 mL) were heated at 100 °C for 4 h. The product was purified by
chromatography on silica gel (hexane/CH2Cl2, 9:1). A total of 0.45
g of alkylidenephospholane 3 was isolated as beige microcrystals
(75% yield). 31P NMR (CDCl3): δ 25.27, 1JP-W 231 Hz. 1H NMR
(CDCl3): δ 1.10 (d, 1H, gem JH-H ) 2.1 Hz, bridge CH); 1.14 (d,
1
gem JH-H ) 2.1 Hz, bridge CH); 1.18 (d, 1H, JHexo-Hendo ) 10.6
Hz endo H); 1.60 (m, 3H, 2 exo H and 1 endo H); 1.66 (br s, 3H,
Me); 1.92 (br s, 3H, Me); 2.03 (t, 1H, 3JP-H ) 7.2 Hz, 3JH-endoH
)
9.2 Hz, junction CH), 2.2 (m, 2H, bridgehead CH2); 2.44, 2.54 (m,
3
2H, phospholane CH2); 3.06 (sextuplet, 1H, JH-endoH ) 9.1 Hz,
3
3JP-H ) 17.8 Hz, JH-H ) 16.8 Hz); 7.3-7.6 (m, 5H, Ph). 13C
NMR (CDCl3): δ 23.40 (d, 3JC-P ) 8.8 Hz, CH3); 26.68 (d, 3JC-P
) 9.0 Hz,CH3); 27.97 (s, bridge CH2); 31.19 (d, 3JC-P ) 13.1 Hz,
2
norbornane CH2); 35.86 (s, norbornane CH2); 40.05 (d, JC-P
)
22.0 Hz, phospholane CH2); 42.50 (s, bridgehead CH); 43.41
2
2
(d, JC-P ) 9.7 Hz, bridgehead CH); 50.45 (d, JC-P ) 2.5 Hz,
1
phospholane CH); 56.45 (d, JC-P ) 25.5 Hz, phospholane CH);
1
129.16, 130.01, 131.94 (Ph C), 134.51 (d, JC-P ) 40.0 Hz, ipso
1
2
C); 139.84 (d, JC-P ) 33.0 Hz, ring sp2 C); 140.94 (d, JC-P
)
2
10.7 Hz,dCMe2); 197.98 (d, JP-C ) 6.9 Hz,cis CO); 199.45
Figure 1. X-ray crystal structure of the norbornene adduct (2).
Main bond lengths (Å) and angles (deg): P-W 2.5444(8), P-C1
1.830(2), P-C4 1.858(2), P-C13 1.841(2), C1-C2 1.513(3), C1-
C10 1.339(3), C2-C3 1.533(3), C3-C4 1.570(3); C1-P-C4 94.9-
(1), C1-P-C13 103.8(1), C13-P-C4 99.8, C4-P-W 119.93(7).
2
(d, JP-C ) 20.7 Hz, trans CO). MS (184W): m/z 594 (M, 18%);
566 (M - CO, 12%); 538 (M - 2 CO, 19%); 510 (M - 3 CO,
83%); 452 (M - 2 - 5 CO, 100%). Anal. Calcd for C23H23O5PW:
C, 46.49; H, 3.90. Found: C, 46.39; H, 3.89.
Cycloadducts with Dimethyl Acetylenedicarboxylate, 3 and
4. Phosphirane 1 (0.5 g, 1 mmol), DMAD (0.25 mL, 2 mmol), and
[Pd(PPh3)4] (0.02 g, 0.2 mmol) in toluene (8 mL) were heated at
100 °C for 4 h. 3 and 4 were purified by chromatography on
silica gel (hexane/CH2Cl2, 1:2), giving a yellow oil, yield 0.51 g
products resulting from the insertion of the CtC triple bond
into the P-C distal and proximal bonds (eq 2).
1
1
(80%). 31PNMR (CDCl3): δ 12.9, JP-W 245 Hz (4); 28.4, JP-W
239 Hz (3).
A mixture of 3 and 4 (0.2 g, 0.3 mmol) and tBuOK (0.05 g, 0.5
mmol) in THF (3 mL) were stirred at room temperature for 0.5 h.
After hydrolysis, extraction with hexane and purification on silica
gel with hexane/CH2Cl2, 1:2, gave 0.06 g of 4 (60% recovery).
1
1
Cycloadduct 4. 31PNMR (CDCl3): δ 12.9, JP-W 245 Hz. -
HNMR (CDCl3): δ 1.84 (s, Me); 1.85 (s, Me); 3.34 (m, 2H, PCH2);
3.58 (s, 3H, OCH3), 3.86 (s, 3H, OCH3), 7.40-7.55 (m, 5H, C6H5).
1
13CNMR (CDCl3): δ 21.7 (s, CH3); 25.6 (s, CH3); 41.6 (d, JP-C
) 30.0 Hz, PCH2); 52.7 (s, OCH3); 53.4 (s, OCH3); 131.0 (s, d
The two products could not be separated, but, fortunately, 3
proved to be unstable in basic medium and was selectively
destroyed by tBuOK without leaving any well-defined product.
Apparently, 3 is more easily deprotonated than 4. We were thus
able to get 4 in the pure state. The most informative datum is
the P-CH2 resonance in the 13C NMR spectrum at 41.68 ppm
(1JC-P ) 30.0 Hz). The data for 3 were obtained from the
mixture. The CH2 resonance appears at 40.80, and the P-C
coupling is much weaker than for 4 (2JC-P ) 11.0 Hz). The
resonance for the Me2CdC carbon appears at 127.39 with the
expected huge P-C coupling (1JC-P ) 47.1 Hz).
We have no obvious explanation for the fact that the reaction
of acetylenedicarboxylate involves both the distal and proximal
P-C bonds. Anyhow, these experiments clearly illustrate the
synthetic potential of alkylidenephosphirane complexes. We plan
to explore other transformations of these species.
CMe2); 132.7 (d, 1JP-C ) 33.7 Hz, ipsoC); 135.2 (d, 1JP-C ) 34.6
2
2
Hz, ring sp2C); 145.0 (d, JP-C ) 6 Hz, ringC), 153.8 (d, JP-C
)
10 Hz, ring CdCMe2); 164.2 (d, 2JP-C ) 12.5 Hz, ester CO); 167.9
(d, 3JP-C ) 11.4 Hz, ester CO); 196.7 (d, 2JP-C ) 7.1 Hz, cis CO);
199.2 (d, JP-C ) 23.5 Hz, trans CO).
2
The spectroscopic data of 3 were deduced from those of the
mixture of 3 and 4 (ratio 53:47) and those of 4.
Cycloadduct 3. 31PNMR (CDCl3): δ 28.4, 1JP-W ) 239 Hz. 1H
NMR (CDCl3): δ 1.61 (s, 6H, Me); 3.56 (s, 3H, OCH3); 3.76
(s, 3H, OCH3), 3.80 (m, 2H, PCH2), 7.60 (m, 5H, C6H5). 13CNMR
3
(CDCl3): δ 22.3 (d,3JP-C ) 9.8 Hz, CH3); 25.4 (d, JP-C ) 11.3
4
Hz, CH3); 40.8 (d,2JP-C ) 11.2 Hz, PCH2); 52.8 (d, JP-C ) 3.1
1
Hz, OCH3); 53.1 (s, OCH3); 127.1 (d, JP-C ) 47.1 Hz, ring Cd
CMe2); 132.0 (s, dCMe2); 139.0 (d, 1JP-C ) 35.5 Hz, ipsoC); 144.7
(d, 1JP-C ) 32.0 Hz, ring sp2C); 144.9 (d, 2JP-C ) 11.5 Hz, ringC),
2
3
163.8 (d, JP-C ) 14.4 Hz, ester CO); 165.4 (d, JP-C ) 9.7 Hz,
2
2
ester CO); 196.7 (d, JP-C ) 9.7 Hz, cis CO); 199.4 (d, JP-C
22.4 Hz, trans CO).
)
Experimental Section
X-ray Structure Data. X-ray structure data: Nonius KappaCCD
diffractometer, φ and ω scans, Mo KR radiation (λ ) 0.71073 Å),
graphite monochromator, T ) 150 K, structure solution with
SIR97,11 refinement against F2 in SHELXL9712 with anisotropic
NMR spectra were recorded on a multinuclear Bruker AVANCE
1
300 MHz spectrometer operating at 300.13 for H, 75.47 for 13C,
and 121.50 MHz for 31P. Chemical shifts are expressed in parts
per million (ppm) downfield from internal tetramethylsilane (1H
and 13C) and external 85% aqueous H3PO4(31P). Elemental analyses
were performed by the Service de microanalyse du CNRS, Gif-
sur-Yvette, France.
(11) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G.; Giacovazzo,
C.; Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.; Spagna, R. SIR97, an
integrated package of computer programs for the solution and refinement
of crystal structures using single crystal data.
(12) Sheldrick, G. M. SHELXL-97; Universita¨t Go¨ttingen, Go¨ttingen,
Germany, 1997.
Norbornene Cycloadduct 2. Phosphirane 1 (0.5 g, 1 mmol),
norbornene (0.2 g, 2 mmol), and 0.02 g of [Pd(PPh3)4] in toluene

3616 Organometallics, Vol. 26, No. 14, 2007
Notes
thermal parameters for all non-hydrogen atoms, calculated hydrogen
positions with riding isotropic thermal parameters. Data collection
for 2: colorless block, 0.20 × 0.20 × 0.20 mm; monoclinic, space
group P21/n, a ) 11.325(5) Å, b ) 13.428(5) Å, c ) 15.724(5) Å,
Crystallographic data for the structure reported in this paper have
been deposited with the Cambridge Crystallographic Data Centre
as supplementary publication no. CCDC 639710. Copies of the data
can be obtained free of charge on application to CCDC, 12 Union
Road, Cambridge CB21EZ, UK (fax (+44)1223-336-033; e-mail
deposit@ccdc.cam.ac.uk).
â ) 109.670(5)°, V ) 2251.6(15) Å3, Z ) 4, Fcalc ) 1.753 g cm-3
,
µ ) 5.232 cm-1; F(000) ) 1160, θmax ) 30.1°, 13 292 data
collected, 5943 unique data with I > 2σ(I), 273 parameters refined,
GOF(F2) ) 1.004, final R indices (R1 ) ∑||Fo| - |Fc||/∑|Fo|, wR2
Acknowledgment. The authors thank Ecole Polytechnique,
the CNRS, and the University of California Riverside for the
financial support of this work.
2
) [∑w(Fo - Fc2)2/∑w(Fo2)2]1/2): R1 ) 0.0215, wR2 ) 0.0540-
(all data); max./min. residual electron density 1.733(0.103)/-1.878-
(0.103) e- Å-3
.
OM070236C