Alkenylzirconocene-mediated preparation of alkenylphosphines

Article abstract of DOI:10.1021/jo071089v

(Chemical Equation Presented) Alkenylphosphines with various substituents were prepared by the reaction of an alkenylzirconocene with a chlorophosphine. Reactions of (α-unsubstituted alkenyl)zirconocenes with Ph₂PCl or PhPCl₂ gave th

Full text of DOI:10.1021/jo071089v

Alkenylzirconocene-Mediated Preparation of Alkenylphosphines
Taichi Miyaji,† Zhenfeng Xi,‡ Masamichi Ogasawara,† Kiyohiko Nakajima,§ and
Tamotsu Takahashi*,†
Catalysis Research Center and Graduate School of Pharmaceutical Sciences, Hokkaido UniVersity, and
SORST, Japan Science and Technology Agency (JST), Kita-ku, Sapporo 001-0021, Japan, College of
Chemistry, Peking UniVersity, Beijing 100871, China, and Department of Chemistry, Aichi UniVersity of
Education, Igaya, Kariya, Aichi 448-8542, Japan
tamotsu@cat.hokudai.ac.jp
ReceiVed May 23, 2007
Alkenylphosphines with various substituents were prepared by the reaction of an alkenylzirconocene
with a chlorophosphine. Reactions of (R-unsubstituted alkenyl)zirconocenes with Ph2PCl or PhPCl2 gave
the corresponding alkenylphosphines in good yields. On the other hand, direct reactions of (R-unsubstituted
alkenyl)zirconocenes with iPr2PCl did not proceed. Analogously, (R-substituted alkenyl)zirconocenes did
not react with chlorophosphines directly. However, these reactions proceeded in the presence of CuCl
affording the corresponding alkenylphosphines as CuCl complexes. Treatment of the copper complexes
with Na2(dtc) (dtc ) N,N-diethyldithiocarbamate) or Na4(edta) liberated free alkenylphosphines from
the copper centers. The overall protocol could be applicable to preparation of a variety of alkenylphosphines
from alkynes via alkenylzirconocene species.
Introduction
is a coupling reaction of an alkenyl-Grignard or an alkenyl-
lithium reagent with an appropriate halophosphorus compound.5
Hydrophosphorylation of alkynes has been developed recently
as an alternative method to prepare these compounds.6,7
We have been interested in reactions between organozirco-
nium nucleophiles and phosphorus electrophiles.8-11 In a
previous paper, we reported reactions of a (â-allylalkenyl)-
Tertiary phosphines are arguably one of the most important
ancillary ligands in organotransition-metal chemistry.1 Among
such compounds, those with alkenyl moieties have attracted
considerable attention because the alkenyl substituents provide
potential for further functionalization of the alkenylphosphines
with the aid of transition-metal catalysts/reagents.2,3 Coordina-
tion chemistry of alkenylphosphines has been explored as well.4
A classical method of preparing alkenylphosphine derivatives
(3) (a) Timmer, M. S. M.; Ovaa, H.; Filippov, D. V.; van der Marel, G.
A.; van Boom, J. H. Tetrahedron Lett. 2000, 41, 8635. (b) Stoianova, D.
S.; Hanson, P. R. Org. Lett. 2001, 3, 2765. (c) Chatterjee, A. K.; Choi,
T.-L.; Grubbs, R. H. Synlett 2001, 1034. (d) Demchuk, O. M.; Pietrusiewicz,
K. M.; Michrowska, A.; Grela, K. Org. Lett. 2003, 5, 3217. (e) Bauer, E.
B.; Gladysz J. A. In Handbook of Metathesis; Grubbs, R. H., Ed.; Wiley-
VCH: Weinheim, 2003; Vol. 2, Chapter 2.11, p 403.
* To whom correspondence should be addressed.
† Hokkaido University.
‡ Peking University.
§ Aichi University of Education.
(1) (a) Tolman, C. A. Chem. ReV. 1977, 77, 4986. (b) Leeuwen, P. W.
N. M.; Kamer, P. C. J.; Reek, J. N. H.; Dierkes, P. Chem. ReV. 2000, 100,
2741. (c) Andersen, N. G.; Keay, B. A. Chem. ReV. 2001, 101, 997.
(2) (a) Leung, P.-H. Acc. Chem. Res. 2004, 37, 169. (b) Aw, B. H.; Leung,
P. H. Tetrahedron: Asymmetry 1994, 7, 1167. (c) Aw, B.-H.; Hor, T. S.
A.; Selvaratnam, S.; Mok, K. F.; White, A. J. P.; Willams, D. J.; Rees, N.
H.; McFarlane, W.; Leung, P.-H. Inorg. Chem. 1997, 36, 2138. (d) Leung,
P. H.; Selvaratnam, S.; Cheng, C. R.; Mok, K. F.; Rees, N. H.; McFarlane,
W. Chem. Commun. 1997, 751. (e) Liu, A.; Mok, K. J.; Leung, P.-H. Chem.
Commun. 1997, 2397. (f) Song, Y.; Mok, K. F.; Leung, P. H.; Chan, S. H.
A. Inorg. Chem. 1998, 37, 6399. (g) Qin, Y.; Selvaratnam, S.; Vittal, J. J.;
Leung, S. H. Organometallics 2002, 21, 5301.
(4) (a) Fryzuk, M. P.; Gao, X.; Rettig, S. Can. J. Chem. 1995, 73, 1175.
(b) Ji, H.-L.; Nelson, J. H.; De Cian, A.; Fischer, J.; Solujic, L.;
Milosavljevic, E. B. Organometallics 1992, 11, 401. (c) Barthel-Rosa, L.
P.; Maitra, K.; Fischer, J.; Nelson, J. H. Organometallics 1997, 16, 1714.
(d) Giordano, R.; Sappa, E.; Predieri, G.; Tiripicchio, A. J. Organomet.
Chem. 1997, 547, 49. (e) Malisch, W.; Rehmann, F.-J.; Jehle, H.; Reising,
J. J. Organomet. Chem. 1998, 570, 107. (f) Coles, S. J.; Jaulds, I.;
Hursthouse, M. B.; Kelly, D. G.; Toner, A. J. Polyhedron 2000, 19, 1271.
(g) Duraczynska, D.; Nelson, J. H. Dalton Trans. 2003, 449.
(5) Maier, L. In Organic Phosphorus Compounds; Kosolapoff, G. M.,
Maier, L., Eds.; Wiley-Interscience: New York, 1972; Vol. 1, Chapter 1,
p 32.
10.1021/jo071089v CCC: $37.00 © 2007 American Chemical Society
Published on Web 10/10/2007
J. Org. Chem. 2007, 72, 8737-8740
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Miyaji et al.
TABLE 1. Preparation of (r-Unsubstituted alkenyl)phosphines 3
SCHEME 1
zirconocene with R2PCl in the presence of CuCl.8c In the
reaction, a phosphine-olefin species generated in situ was
trapped by Cu(I) as a chelating ligand. Treatment of the Cu
complex with Na2(dtc) or Na4(edta) dissociated the coordinating
phosphine-olefin ligand from the metal center, and the free
ligand was isolated in a pure form.
In this report, we have examined application of the overall
protocol for the synthesis of a variety of alkenylphosphines
(Scheme 1). Because various alkenylzirconocene species of
different substitution patterns can be easily prepared from easily
available materials via (i) oxidative addition of an alkenyl halide
to Cp2Zr(II),12 (ii) hydrozirconation of an alkyne with the
Schwartz’s reagent,13 or (iii) zirconacyclopentene-mediated
carbozirconation of an alkyne14 (Scheme 2), reactions of such
alkenylzirconocenes with appropriate phosphorus electrophiles
should provide a general route to alkenylphosphines. During
the investigation, it was found that transmetalation of the alkenyl
moieties from Zr(IV) to Cu(I) was required to facilitate the
Cp2Zr(alkenyl)Cl R1 PCl3-n CuCl
product
yielda
(%)
n
entry
1
2
(%)
3
1
2
3
1a
1b
1a
1a
1c
1a
1b
2m
2m
2n
2n
2n
2o
3am
3bm
NR
78 (87)
76 (90)
4b
5c
6
15
15
3an-BH3 33 (37)
3cn
3ao
67
55 (98)
7b
2o
3bo-BH3 33 (46)
a Isolated yields by silica gel chromatography. NMR yields are given in
parentheses. b Reaction mixture was treated with 1.5 equiv of BH3-THF.
c Reaction mixture was treated with 2.2 equiv of Na2(btc) (vide infra).
SCHEME 2
(6) (a) Han, L.-B.; Tanaka, M. J. Am. Chem. Soc. 1996, 118, 1571. (b)
Han, L.-B.; Choi, N.; Tanaka, M. Organometallics 1996, 15, 3259. (c) Han,
L.-B.; Hua, R.; Tanaka, M. Angew. Chem., Int. Ed. 1998, 37, 94. (d) Zhao,
C.-Q.; Han, L.-B.; Goto, M.; Tanaka, M. Angew. Chem., Int. Ed. 2001, 40,
1929. (e) Kazankova, M. A.; Efimova, I. V.; Kochetkov, A. N.; Afanas’ev,
V. V.; Beletskaya, I. P.; Dixneuf, P. H. Synlett 2001, 497. (f) Wicht, D. K.;
Glueck, D. S. In Catalytic Heterofunctionalization; Togni, A., Grutzmacher,
H., Eds.; Wiley-VCH: Weinheim, 2001; Chapter 5, p 143.
(7) For other methods of preparing alkenylphosphines, see: (a) Walsh,
E. N.; Beck, T. M.; Woodstock, W. H. J. Am. Chem. Soc. 1955, 77, 929.
(b) Maier, L.; Seyferth, D.; Stone, F. G. A.; Rochow, E. G. J. Am. Chem.
Soc. 1957, 79, 5884. (c) Aguiar, A. M.; Daigle, D. J. Am. Chem. Soc. 1964,
86, 2299. (d) Clark, P. W.; Cartis, J. L. S.; Garrou, P. E.; Hartwell, G. E.
Can. J. Chem. 1974, 52, 1714. (e) Tunney, S. E.; Stille, J. K. J. Org. Chem.
1987, 52, 748. (f) Ichikawa, J.; Yonemaru, L.; Minami, T. Synlett 1992,
833. (g) Lipshutz, B. H.; Buzard, D. J.; Yun, C. S. Tetrahedron Lett. 1999,
40, 201. (h) Kazankova, M. A.; Lutsenko, S. V.; Beletskaya, I. P.
Tetrahedron Lett. 1999, 40, 569. (i) Kazankova, M. A.; Chirkov, E. A.;
Kochetkov, A. N.; Efimora, I. V.; Beletskaya, I. P. Tetrahedron Lett. 1999,
40, 573. (j) Gilbertson, S. R.; Ju, Z.; Starkey, G. W. Tetrahedron Lett. 1999,
40, 8509. (k) Zhong, P.; Huang, X.; Xiong, Z.-X. Synlett 1999, 721.
(8) (a) Takahashi, T.; Kotora, M.; Hara, R.; Xi, Z. Bull. Chem. Soc. Jpn.
1999, 72, 2591. (b) Kotora, M.; Xi, Z.; Takahashi, T. J. Synth. Org. Chem.,
Jpn. 1997, 55, 958. (c) Miyaji, T.; Xi, Z.; Nakajima, K.; Takahashi, T.
Organometallics 2001, 20, 2859.
reactions of sterically encumbered substrates/reagents. We report
herein details of the synthesis of alkenylphosphines via alk-
enylzirconocenes.
Results and Discussion
Reactions of (R-Unsubstituted alkenyl)zirconocene Species.
When an alkenylzirconium compound 1a, which was derived
from phenylacetylene by hydrozirconation, was treated with Ph2-
PCl 2m in THF at room temperature, the reaction proceeded
smoothly to give diphenyl(â-styryl)phosphine 3am in 87% yield
(Table 1, entry 1).15 Analogously, (1-octenyl)diphenylphosphine
3bm was obtained in 90% yield from 1b and 2m (entry 2). On
the other hand, reactions of 1a with 2n, which was with
sterically demanding isopropyl substituents, did not proceed
under the identical conditions (entry 3). It was found that
addition of a catalytic amount of CuCl (15%)8c,10,11 realized the
reaction between 1a and 2n. The corresponding alkenylphos-
phine 3an, which was air-sensitive, was isolated as a stable BH3-
adduct after treating the crude reaction mixture with BH3-THF
(entry 4, see also entry 5).16 A reaction of 1a with 0.5 equiv of
dichlorophenylphosphine 2o under identical conditions also
proceeded smoothly in the absence of CuCl and the correspond-
(9) (a) Fagan, P. J.; Nugent, W. A. J. Am. Chem. Soc. 1988, 110, 2310.
(b) Fagan, P. J.; Nugent, W. A.; Calabrese, J. C. J. Am. Chem. Soc. 1994,
116, 1880.
(10) Reactions of zirconacyclopentadienes with chlorodiphenylphosphine
in the presence of CuCl were reported, see: (a) Doherty, S.; Knight, J. G.;
Robins, E. G.; Scanlan, T. H.; Champkin, P. A.; Clegg, W. J. Am. Chem.
Soc. 2001, 123, 5110. (b) Doherty, S.; Robins, E. G.; Nieuwenhuyzen, M.;
Knight, J. G.; Champkin, P. A.; Clegg, W. Organometallics 2002, 21, 1383.
(11) For preparation of (E)-2-arylvinylphosphonate from the reaction of
(E)-2-arylvinylzirconocene and chlorophosphonate using CuBr as a catalyst,
see: Zhong, P.; Huang, X.; Xiong, Z.-X. Synlett 1999, 721.
(12) Takahashi, T.; Kotora, M.; Fischer, R.; Nishihara, Y.; Nakajima,
K. J. Am. Chem. Soc. 1995, 117, 11039.
(13) (a) Hart, D. W.; Schwartz, J. J. Am. Chem. Soc. 1974, 96, 8115. (b)
Hart, D. W.; Blackburn, T. F.; Schwartz, J. J. Am. Chem. Soc. 1975, 97,
679. (c) Igau, A. In Catalytic Heterofunctionalization; Togni, A., Grutz-
macher, H., Eds.; Wiley-VCH: Weinheim, 2001; Chapter 8, p 253. (d)
Lipshutz, B. H.; Pfeiffer, S. S.; Noson, K.; Tomioka, T. In Titanium and
Zirconium in Organic Synthesis; Marek, I., Ed.; Wiley-VCH: Weinheim,
2002; Chapter 4, p. 110.
(14) (a) Takahashi, T.; Aoyagi, K.; Hara, R.; Suzuki, N. Chem. Commun.
1993, 1043. (b) Takahashi, T.; Suzuki, N;, Kageyama, M.; Kondakov, D.
Y.; Hara, R. Tetrahedron Lett. 1993, 40, 4811. (c) Takahashi, T.; Kondakov,
D. Y.; Suzuki, N. Tetrahedron Lett. 1993, 41, 6571. (d) Takahashi, T.; Xi,
C.; Ura, Y.; Nakajima, K. J. Am. Chem. Soc. 2000, 112, 3228.
(15) Fryzuk, M. D.; Bates, G. S.; Stone, C. J. Org. Chem. 1988, 53,
4425.
8738 J. Org. Chem., Vol. 72, No. 23, 2007

Alkenylzirconocene-Mediated Preparation of Alkenylphosphines
TABLE 2. Preparation of (r-Substituted alkenyl)phosphines 6
entry
alkenyl-Zr 4
R1 PCl 2
yield of 5a (%)
Cu scavenger
yield of 6a (%)
2
1
2
4a
4b
4c
4c
4c
4d
4d
4e
4f
2m
2m
2m
2m
2n
2m
2n
2n
63 (84), 5am
b
70 (80), 5cm
b
Na2(dtc)
Na2(dtc)
Na2(dtc)
Na2(dtc)
Na4(edta)
Na2(dtc)
Na4(edta)
Na2(dtc)
Na2(dtc)
Na2(dtc)
Na4(edta)
67 (84), 6am
65 (88), 6bm
66 (94), 6cm
49 (71), 6cm
44 (-), 6cn
78 (90), 6dm
52 (-), 6dn
75 (88), 6en
73 (80), 6fm
71 (85), 6fn
73 (83), 6gn
3
4c
5
50 (81), 5cn
b
6
7
50 (72),d 5dn
b
8e
9
2m
2n
2n
56 (78), 5fm
55 (75), 5fn
64 (83), 5gn
10
4f
4g
11e
a Isolated yields by silica gel chromatography. NMR yields are given in parentheses. b The corresponding Cu complexes were not isolated. c A catalytic
amount of CuCl (0.2 equiv) was used. d Taken from ref 8c. e The first step was carried out at 50 °C.
SCHEME 3
ing dialkenylphosphine 3ao was obtained in good yield (entry
6). Note that a reaction of 1a and 2o in a 1:1 molar ratio also
afforded 3ao as a sole coupling product, and no monoalkenyl-
chlorophosphine was detected. This indicates that substitution
of the second P-Cl bond by the alkenylmetal reagent was faster
than the first one.
Reactions of (R-Substituted alkenyl)zirconocene Species.
When alkenylzirconium species 4a, which was generated in situ
by oxidative addition of 2-chloropropene to the Negishi’s
(Persubstituted alkenyl)zirconocene compounds can be easily
prepared from alkynes and zirconocene dichloride (Scheme 2).
We reported various carbozirconation of alkynes utilizing
reagent Cp2ZrnBu2,12 was treated with Ph2PCl 2m in the
presence of 1 equiv of CuCl, the reaction proceeded smoothly
to give a dinuclear [(µ-Cl)Cu(I)]2 complex 5am in 84% yield
(Table 2, entry 1). In a 31P NMR spectrum of the copper
complex, only one broad signal was observed at δ 0.6, which
was assignable to phosphorus coordinating to the copper center.
In the absence of CuCl, the desired alkenylphosphine was not
formed even at elevated temperature (80 °C, bath temperature).
In this reaction, transmetalation of the Zr-alkenyl moiety to a
Cu(I) center was essential as reported previously.8c,10,11 When
Na2(dtc) was added to the reaction mixture containing the
phosphine-copper complex 5am, the color of the solution
immediately changed from pale yellow to dark yellow giving
free diphenyl(2-propenyl)phosphine 6am in 84% yield (Scheme
3). The 31P NMR spectrum of 6am showed upper field shift of
the signal, indicating the dissociation of the phosphine.
reactions of a zirconacyclopentene with methanol,14a allyloxytrime-
thylsilane,14b or 4-bromo-1-butene.14c These reactions give
alkenylzirconocene compounds with ethyl (4c), allyl (4d-e), or
cyclopropylmethyl (4f-g) substituents at the â-position of the
alkenyl moieties, respectively. The alkenylzirconocene species
were generated in situ and reacted with chlorophosphine
derivatives (2m,n) in the presence of CuCl affording the
dinuclear [(µ-Cl)Cu]2 complexes 5 coordinated by the corre-
sponding alkenylphosphines in good yields (Table 2, entries 3,
5, 7, and 9-11). When diphenylacetylene was used for
generating the (persubstituted alkenyl)zirconocenes, a higher
temperature was required to accomplish the reaction (Table 2,
entry 11).
As mentioned above, treatment of the copper complexes with
Na2(dtc) induced dissociation of the coordinating alkenylphos-
phines and the free phosphines 6 were isolated in pure form.
This protocol could be extended to one-pot synthesis of free
alkenylphosphines from alkynes without isolating the intermedi-
ary copper complexes (Table 2, entries 2, 4, 6, and 8). Aqueous
Na4(edta) was also applicable as a Cu(I) scavenger (Table 2,
entries 5, 7, and 11). For the one-pot procedure, a catalytic
amount of CuCl (20 mol %) was enough to give 6cm, albeit in
the moderate yield (Table 2, entry 4).
In the same way, (R,â-disubstituted alkenyl)zirconocene 4b,
generated from the Schwartz’s reagent Cp2Zr(H)Cl and 4-octyne,
reacted with 2m in the presence of CuCl, and after treatment
with Na2(dtc) the corresponding alkenylphosphine 6bm was
obtained in 88% yield (Table 2, entry 2). This reaction also did
not proceed in the absence of CuCl.
(16) (a) Schmidbaur, H. J. Organomet. Chem. 1980, 200, 287. (b) Brunel,
J. M.; Faure, B.; Maffei, M. Coord. Chem. ReV. 1998, 178-180, 665. (c)
Carboni, B.; Monnier, L. Tetrahedron 1999, 55, 1197. (d) Imamoto, T.;
Oshiki, T.; Onozawa, T.; Kusumoto, T.; Sato, K. J. Am. Chem. Soc. 1990,
112, 5244.
The X-ray single-crystal structures of 5cn and 5gn are given
in Figures 1 and 2, respectively. These results showed the
J. Org. Chem, Vol. 72, No. 23, 2007 8739

Miyaji et al.
(I) salt to proceed. Analogously, (R-substituted alkenyl)-
zirconocene species reacted with chlorophosphines in the
presence of CuCl, affording the corresponding alkenylphosphine
as Cu(I) complexes. Free alkenylphosphines were obtained by
the treatment of the alkenylphosphine-Cu(I) complexes with
Na2(dtc) or Na4(edta).
Experimental Section
Preparation of Alkenylphosphines by the Direct Reaction of
an Alkenylzirconocene with a Chlorophosphine. To a THF
solution of Cp2Zr(alkenyl)X (1.1 equiv to R2PCl or 2.2 equiv to
RPCl2), which was generated in situ as reported previously,12,13 was
added RnPCl3-n (2) by means of syringe at 0 °C. After the mixture
was stirred for 3 h at room temperature, the reaction mixture was
treated with BH3‚THF (1.2 equiv) if necessary. The product was
extracted with hexane or Et2O and then purified by column
chromatography on silica gel. The yields of the alkenylphosphines
3 are described in Table 1. The characterization data of the products
are listed in the Supporting Information.
Preparation of Alkenylphosphines from an Alkenylzir-
conocene and a Chlorophosphine in the Presence of CuCl. To
a THF solution of Cp2Zr(alkenyl)X (1.1 equiv to R2PCl or 2.2 equiv
to RPCl2), which was generated in situ as reported previously,12-14
was added R2PCl (2) by means of syringe at 0 °C. Subsequently,
an appropriate amount of CuCl (see Tables 1 and 2) was added to
the mixture at this temperature. After the mixture was stirred for 3
h at room temperature, the reaction mixture was treated with Na2-
(dtc) (2.0 equiv) or Na4(edta) (2.0 equiv) at the same temperature.
The mixture was diluted with hexane and then filtered. After
removal of the volatiles, the product was purified by column
chromatography on silica gel. The yields of the alkenylphosphines
3 and 6 are described in Tables 1 and 2. The compound 6dm is
known compound and was characterized by comparison of the
spectral data with those reported previously.8c The characterization
data of the other products are listed in the Supporting Information.
Preparation of Dinuclear Copper/Chlorophosphine Com-
plexes (5). To a THF solution of Cp2Zr(alkenyl)X (4), which was
generated in situ as reported previously,13,14 were added R2PCl (1.0
equiv) and CuCl (1.2 equiv) successively at 0 °C. After the mixture
was stirred for 3 h at room temperature, the resulting black solution
was quenched with 3 N HCl, extracted with ethyl acetate, washed
with brine, and dried over MgSO4. After filtration, the yellow
solution was concentrated and subjected to purification through
column chromatography on silica gel. The yields of the copper
complexes 5 are described in Table 2. The characterization data of
the complexes are listed in the Supporting Information.
FIGURE 1. ORTEP drawing of 5cn 50% thermal ellipsoids. Selected
bond lengths (Å) and angles (deg): Cu(1)-P(1) ) 2.1919(7), Cu(1)-
Cl(1) ) 2.3205(9), Cu(1)-Cl(1*) ) 2.3216(9), C(1)-C(2) ) 1.332-
(4); Cl(1)-Cu(1)-P(1) ) 131.93(3), Cl(1*)-Cu(1)-P(1) ) 129.75(3),
Cl(1)-Cu(1)-Cl(1*) ) 98.11(3), Cu(1)-Cl(1)-Cu(1*) ) 81.89(3).
FIGURE 2. ORTEP drawing of 5gn 50% thermal ellipsoids. Selected
bond lengths (Å) and angles (deg): Cu(1)-P(1) ) 2.191(1), Cu(1)-
Cl(1) ) 2.280(2), Cu(1)-Cl(1*) ) 2.325(2), C(1)-C(2) ) 1.346(6);
Cl(1)-Cu(1)-P(1) ) 131.11(5), Cl(1*)-Cu(1)-P(1) ) 128.14(6), Cl-
(1)-Cu(1)-Cl(1*) ) 100.34(5), Cu(1)-Cl(1)-Cu(1*) ) 79.66(5).
formation of bis(µ-chloride) dimers in which the alkenylphos-
phines and Cu(I) were complexed with a 1:1 molar ratio.
Acknowledgment. Z.X. thanks the National Natural Science
Foundation of China (29702001), the National Science Fund
for Distinguished Young Scholars (29825105), and the Peking
University President Fund for financial support for part of this
work.
Conclusions
In summary, this work describes the general method for the
preparation of a variety of alkenylphosphines via alkenylzir-
conocene compounds. When an alkenyl group had no substituent
at the R-position, alkenylzirconocene reacted with Ph2PCl or
PhPCl2 directly. On the other hand, a reaction of (R-unsubsti-
tuted alkenyl)zirconocene with iPr2PCl required addition of Cu-
Supporting Information Available: Characterization data and
NMR spectra for all new compounds; crystallographic data for 5cn
and 5gn (CIF). This material is available free of charge via the
Internet at http://pubs.acs.org.
JO071089V
8740 J. Org. Chem., Vol. 72, No. 23, 2007