Preparation of vinyl allenes from 1-lithio-1,3-dienyl phosphine oxides and aldehydes by the Wittig-Horner reaction

Article abstract of DOI:10.1021/jo051178c

Vinyl allenes were prepared in high yields by the Wittig-Horner reaction of 1-Lithio-1,3-dienyl phosphine oxides with aldehydes. 1-Lithio-1,3-dienyl phosphine oxides were generated in situ from lithiation of 1-iodo-1,3-dienyl phosphine oxides, which were obtained by iodination of α- phosphinozirconacyclopentadienes. As a whole, a vinyl allene is synthesized from two different alkynes and one aldehyde.

Full text of DOI:10.1021/jo051178c

Preparation of Vinyl Allenes from 1-Lithio-1,3-dienyl Phosphine
Oxides and Aldehydes by the Wittig-Horner Reaction
Zhenfeng Xi,*,† Wen-Xiong Zhang,† Zhiyi Song,† Weixin Zheng,† Fanzhi Kong,† and
Tamotsu Takahashi*,‡
Peking University-Hokkaido University Joint Lab, College of Chemistry, Peking University, Beijing
100871, China, and Catalysis Research Center, Graduate School of Pharmaceutical Sciences, Hokkaido
University and SORST, Japan Science and Technology Agency (JST), Kita-Ku, Sapporo 001-0021, Japan
zfxi@pku.edu.cn
Received June 11, 2005
Vinyl allenes were prepared in high yields by the Wittig-Horner reaction of 1-lithio-1,3-dienyl
phosphine oxides with aldehydes. 1-Lithio-1,3-dienyl phosphine oxides were generated in situ from
lithiation of 1-iodo-1,3-dienyl phosphine oxides, which were obtained by iodination of R-phosphi-
nozirconacyclopentadienes. As a whole, a vinyl allene is synthesized from two different alkynes
and one aldehyde.
Introduction
synthesis.1-15 Several useful methods have been reported,
mainly based on reactions of organometallic reagents
with suitably functionalized propargyl derivatives.2-14
We have recently investigated reactions of 1-lithio-1,3-
dienes 1 with unsaturated substrates.16 Treatment of
1-lithio-1,3-dienes 1 (X ) alkyl, aryl or SiMe3) with
aldehydes or ketones afforded stereodefined dienols or
Development of synthetic methods for vinyl allenes has
attracted much attention,1-15 since vinyl allenes, which
bear a cumulenic and conjugated vinyl functionality, are
useful and unique precursors or intermediates in organic
† Peking University.
‡ Hokkaido University.
(1) (a) Brandsma, L.; Verkruijsse, H. D. Synthesis of Acetylenes,
Allenes, Cumulenes, A Laboratory Manual; Elsevier: Amsterdam,
1981. (b) Schuster, H. F.; Coppola, G. M. Allenes in Organic Synthesis;
John Wiley and Sons: New York, 1984. (c) Bruneau, C.; Dixneuf, P.
H. Allenes and Cumulenes. In Comprehensive Organic Functional
Group Transformations; Elsevier: Oxford, 1995; Vol. 1, p 966 and
references therein. (d) Marshall, J. A. Chem. Rev. 1996, 96, 31. (e)
Murakami, M.; Itami, K.; Ubukata, M.; Tsuji, I.; Ito, Y. J. Synth. Org.
Chem. Jpn. 1998, 56, 406. (f) Hashmi, A. S. K. Angew. Chem., Int. Ed.
2000, 39, 3590. (g) Huang, W. W.; Tidwell, T. T. Synthesis 2000, 457.
(h) Hoffmann-Roder, A.; Krauce, N. Angew. Chem., Int. Ed. 2002, 41,
2933. (i) Sydnes, L. K. Chem. Rev. 2003, 103, 1133. (j) Ma, S. Acc.
Chem. Res. 2003, 36, 701. (k) Hoffmann-Roder, A.; Norbert, K.
Tetrahedron 2004, 60, 11671. (l) Ma, S. Eur. J. Org. Chem. 2004, 1175.
(m) Ma, S. Chem. Rev. 2005, 105, 2829.
(2) (a) Lopez, S.; Rey, J. G.; Rodr´ıguez, J.; de Lera, A. R. Tetrahedron
Lett. 1995, 36, 4669. (b) Lopez, S.; Rodr´ıguez, J.; Rey, J. G.; de Lera,
A. R. J. Am. Chem. Soc. 1996, 118, 1881. (c) de Lera, A. R.; Torrado,
A.; Rey, J. G.; Lopez, S. Tetrahedron Lett. 1997, 38, 7421. (d) de Lera,
A. R.; Rey, J. G.; Hrovat, D.; Iglesias, B.; Lopez, S. Tetrahedron Lett.
1997, 38, 7425. (e) Iglesias, B.; de Lera, A. R.; Rodriguez-Otero, J.;
Lopez, S. Chem. Eur. J. 2000, 6, 4021. (f) Souta, J. A.; Lopez, S.; Faza,
O. N.; Alvarez, R.; de Lera, A. R. Org. Lett. 2005, 7, 1565.
(3) (a) Regas, D.; Afonso, M. M.; Galindo, A.; Palenzuela, J. A.
Tetrahedron Lett. 2000, 41, 6781. (b) Regas, D.; Ruiz, J. M.; Afonso,
M. M.; Galindo, A.; Palenzuela, J. A. Tetrahedron Lett. 2003, 44, 8471.
(c) Regas, D.; Afonso, M. M.; Rodriguez, M. L.; Palenzula, J. A. J. Org.
Chem. 2003, 68, 7845. (d) Regas, D.; Afonso, M. M.; Palenzuela, J. A.
Synthesis 2004, 757.
(4) (a) Murakami, M.; Itami, K.; Ito, Y. Angew. Chem., Int. Ed. Engl.
1996, 34, 2691. (b) Murakami, M.; Itami, K.; Ito, Y. Synlett 1999, 951.
(c) Murakami, M.; Itami, K.; Ito, Y. Organometallics 1999, 18, 1326.
(d) Murakami, M.; Ashida, S.; Matsuda, T. J. Am. Chem. Soc. 2004,
126, 10838.
(5) (a) Okamoto, S.; Takayama, Y.; Gao, Y.; Sato, F. Synthesis 2000,
975. (b) Delas, C.; Urabe, H.; Sato, F. J. Am. Chem. Soc. 2001, 123,
7937. (c) Tanaka, R.; Sasaki, M.; Sato, F.; Urabe, H. Tetrahedron Lett.
2005, 46, 329.
(6) Descoins, C.; Henrick, C. A.; Siddall, J. B. Tetrahedron Lett. 1972,
3777.
(7) (a) Spino, C.; Thibault, C.; Gingras, S. J. Org. Chem. 1998, 63,
5283. (b) Spino, C.; Frechette, S. Tetrahedron Lett. 2000, 41, 8033.
(8) Nakamura, H.; Onagi, S.; Kamakura, T. J. Org. Chem. 2005,
70, 2357.
(9) Yoshikawa, E.; Kasahara, M.; Asao, N.; Yamamoto, Y. Tetrahe-
dron Lett. 2000, 41, 4499.
10.1021/jo051178c CCC: $30.25 © 2005 American Chemical Society
Published on Web 10/04/2005
J. Org. Chem. 2005, 70, 8785-8789
8785

Xi et al.
TABLE 1. Preparation of 1-Iodo-1,3-dienyl Phosphine
SCHEME 1
Oxides from Two Different Alkynes via
r-Phosphinozirconacyclopentadienes
cyclopentadienes (Scheme 1).17 However, reactions of
1-lithio-1,3-dienyl phosphine oxides 2 (X ) Ph2PO) with
aldehydes afforded stereodefined vinyl allenes 3 via the
Wittig-Horner reaction.18,19 In this paper, we report the
preparation of vinyl allenes by the Wittig-Horner reac-
tion from 1-lithio-1,3-dienyl phosphine oxides 2 with
aldehydes. We also report the scope and limitations of
iodination reactions of R-phosphinozirconacyclopentadi-
enes that produce the starting materials 1-iodo-1,3-dienyl
phosphine oxides.20
Results and Discussion
Preparation of 1-Iodo-1,3-dienyl Phosphine Ox-
ides from Iodination of r-Phosphinozirconacyclo-
pentadienes. Cross-coupling of an alkynylphosphine
with a different alkyne took place highly selectively on a
low valent zirconocene to afford R-phosphinozirconacy-
clopentadienes 4.20,11 Treatment of 4 with 2 equiv of I2
afforded 1-iodo-1,3-dienyl phosphine oxides 5 as the only
(10) (a) Miquel, Y.; Igau, A.; Donnadieu, B.; Majoral, J. P.; Dupuis,
L.; Pirio, N.; Meunier, P. Chem. Commun. 1997, 279. (b) Zablocka,
M.; Miquel, Y.; Igau, A.; Majoral, J. P.; Skowronska, A. Chem.
Commun. 1998, 1177. (c) Quntar, A. A. A.; Srebnik, M. Org. Lett. 2004,
6, 4243. (d) Ben-Valid, S.; Quntar, A. A. A.; Srebnik, M. J. Org. Chem.
2005, 70, 3554.
(11) Huang, W. W.; Fang, D.; Temple, K.; Tidwell, T. T. J. Am. Chem.
Soc. 1997, 119, 2832.
(12) Morwick, T. M.; Paquette, L. A. J. Org. Chem. 1997, 62, 627.
(13) (a) Koop, U.; Handke, G.; Krause, N. Liebigs Ann. 1996, 1487.
(b) Purpura, M.; Krause, N. Eur. J. Org. Chem. 1999, 267. (c) Krause,
N.; Purpura, M. Angew. Chem., Int. Ed. 2000, 39, 4355.
(14) Werner, H. Chem. Commun. 1997, 903.
(15) (a) Jones, E. R. H.; Lee, H. H.; Whitting, M. C. J. Chem. Soc.
1960, 341. (b) Dulcere, J. P.; Roumestant, M. L.; Gore, J. Tetrahedron
Lett. 1972, 4465. (c) Gore, J.; Dulcere, J. P. J. Chem. Soc., Chem.
Commun. 1972, 866. (d) Baudouy, R.; Gore, J. J. Chem. Res. 1981,
278.
a Isolated yields.
(16) (a) Chen, J.; Song, Q.; Wang, C.; Xi, Z. J. Am. Chem. Soc. 2002,
124, 6238. (b) Wang, C.; Chen, J.; Song, Q.; Li, Z.; Xi, Z. Arkivoc 2003,
Part ii, 155. (c) Song, Q.; Li, Z.; Chen, J.; Wang, C.; Xi, Z. Org. Lett.
2002, 4, 4627. (d) Xi, Z. Eur. J. Org. Chem. 2004, 2773. (e) Wang, C.;
Lu, J.; Mao, G.; Xi, Z. J. Org. Chem. 2005, 70, 5150.
(17) Fang, H.; Song, Q.; Wang, Z.; Xi, Z. Tetrahedron Lett. 2004,
45, 5159.
(18) (a) Pelter, A.; Smith, K.; Jones, K. D. J. Chem. Soc., Perkin
Trans. 1 1992, 747. (b) Reynolds, K. A.; Dopico, P. G.; Sundermann,
M. J.; Hughes, K. A.; Finn, M. G. J. Org. Chem. 1993, 58, 1298. (c)
Reynolds, K. A.; Dopico, P. G.; Brody, M. S.; Finn, M. G. J. Org. Chem.
1997, 62, 2564. (d) Fox, D. J.; Medlock, J. A.; Vosser, R.; Warren, S. J.
Chem. Soc., Perkin Trans. 1 2001, 2240. (e) Inoue, H.; Tsubouchi, H.;
Nagaoka, Y.; Tomioka, K. Tetrahedron 2002, 58, 83. (f) Liu, B.; Wang,
K. K.; Petersen, J. L. J. Org. Chem. 1996, 61, 8503. (g) Wang, K. K.;
Zhang, H. R.; Petersen, J. L. J. Org. Chem. 1999, 64, 1650. (h) Huang,
X.; Xiong, Z. Chem. Commun. 2003, 1714. (i) Huang, X.; Xiong, Z.
Tetrahedron Lett. 2003, 44, 5913.
product in moderate isolated yields with high selectivity
(Table 1).
Similarly, one Ph2P- or two Ph2P-substituted diynes 6
could also be applied to the above reaction. Treatment
of a THF solution of Cp2ZrEt2 or Cp2ZrBu2 with diynes 6
resulted in the formation of the R-phosphinobicyclozir-
conacyclopentadienes 7. Hydrolysis with 3 N HCl af-
forded products 8 in more than 80% isolated yields. As
in the case for iodination of the in situ generated
intermediate 4, treatment of 7a with 2 equiv of I2 gave
the monoiodination product 9a. The diiodo compound 10a
was formed in good isolated yield when 7a was first
treated with 2 equiv of I2 and followed by further
treatment with 1 equiv of CuCl and 1 equiv of I2.21
(19) Johnson, A. W.; Kaska, W. C.; Starzewski, K. A. O.; Dixon, D.
A. Ylides and Imines of Phosphorus; Wiley-Interscience: New York,
1993; p 314.
(20) Xi, Z.; Zhang, W.; Takahashi, T. Tetrahedron Lett. 2004, 45,
2427.
(21) Xi, C.; Huo, S.; Afifi, T. H.; Hara, R.; Takahashi, T. Tetrahedron
Lett. 1997, 38, 4099.
8786 J. Org. Chem., Vol. 70, No. 22, 2005

Preparation of Vinyl Allenes
SCHEME 2
These results suggested dienols 12 that came from
hydrolysis of intermediate lithium alkoxides 14 and vinyl
allenes 13 were formed by spontaneous Wittig-Horner
elimination of lithium diphenylphosphinate from 14.19
A
proposed mechanism for the formation of 12 and 13 is
given in Scheme 4. To confirm the formation of interme-
diate 14, we treated the isolated alcohol 12a with n-BuLi
and t-BuOK, and the vinyl allene 13a was formed in a
quantitative yield.
To obtain the vinyl allenes 13 selectively and in high
yields, we applied the model reaction of 2a with benzal-
dehyde to optimize elimination conditions of lithium
diphenylphosphinate from 14. These results are sum-
marized in Table 2. In the absence of t-BuOK, vinyl allene
13a was formed in 5% isolated yield at room temperature
and 76% of 12a was obtained after hydrolysis (Entry 1).
When the reaction time was prolonged, the yield of 13a
increased to 30%. However, when the reaction time was
increased to 12 or 24 h, no improvement of the yield of
13a was observed. These results indicated that the direct
conversion of lithium alkoxides 14 to vinyl allenes 13 was
not efficient. At the same time, when reaction tempera-
ture increased, the reaction was not clean. Therefore,
promotion of elimination of lithium alkoxides from 14 was
critical for successful preparation of vinyl allenes 13.
Tomioka and co-workers have reported that t-BuOK, as
a co-base, can work effectively for the activation of
lithium alkoxides to afford alkenes.18e Therefore, we chose
t-BuOK as an activating co-base of 14. When 1 equiv of
t-BuOK was added to the reaction mixture and the
mixture was sirred for 0.5 h at room temperature, the
isolated yield of vinyl allene 13a increased up to 85% as
a single product and 12a was not observed (entry 9).
These results indicate that t-BuOK, as a strong co-base,
can also promote the Wittig-Horner elimination of
diphenylphosphinate derivatives from 14. Use of 9a and
10a,b for the Wittig-Horner reaction generated a mix-
ture of products.
However, when 7b was treated with 2 equiv of I2, it
afforded a mixture of mono- and diiodide products.
Treatment of 7b with 4 equiv of I2 afforded the diiodo
compound 10b (Scheme 2).
Preparation of Vinyl Allenes from 1-Lithio-1,3-
dienyl Phosphine Oxides and Aldehydes. Lithiation
of 1-iodo-1,3-dienes with 2 equiv of t-BuLi at -78 °C gave
their corresponding 1-lithio-1,3-dienes in quantitative
yields, as we have already reported.16,17 Treatment of
1-lithio-1,3-dienes with aldehydes afforded dienols or
cyclopentadienes depending on the nature of substituents
and hydrolysis conditions.17 Similarly, 1-lithio-1,3-dienyl
phosphine oxide 2a was prepared by treatment of 1-iodo-
1,3-dienyl phosphine oxide 5a with 1 equiv of n-BuLi in
Et2O at -78 °C for 0.5 h. After deuterolysis with 20%
DCl in D2O, 11a was obtained in 99% GC yield with
>95% deuterium incorporation (90% isolated yield).
Reaction of 2a with benzaldehyde at -78 °C for 1 h
produced 12a as a single product in 82% isolated yields
after quenching with saturated NaHCO3. When the
reaction mixture of 2a with benzaldehyde was allowed
to warm to room temperature for 24 h and quenched with
saturated NaHCO3, in addition to 12a, a vinyl allene 13a
was also obtained in 30% isolated yield (Scheme 3).
Results for the formation of vinyl allenes from 1-lithio-
1,3-dienyl phosphine oxides 2 and aldehydes are given
in Table 3. The reaction conditions are given in Scheme
5. As shown in Table 3, all aromatic, aliphatic and R,â-
unsaturated aldehydes were suitable for the formation
of vinyl allenes in more than 70% isolated yields under
SCHEME 3
J. Org. Chem, Vol. 70, No. 22, 2005 8787

Xi et al.
TABLE 3. Formation of Vinyl Allenes from
1-Lithio-1,3-dienyl Phosphine Oxide and Aldehydes
SCHEME 4
TABLE 2. Elimination Conditions for Formation of
Vinyl Allenes
yields (%)a
entry
equiv of t-BuOK
time (h)
12a
13a
1
2
3
4
5
6
7
8
9
0
1
2
76
70
60
50
48
48
25
0
5
10
18
25
30
30
55
82
85
0
0
3
0
6
0
12
24
1
0
0.5
0.5
1
2
0.5
0
a Isolated yields.
the present reaction conditions. At the same time, the
substituent R could be an aromatic or aliphatic group.
Obviously, this method provides a convenient way to
obtain multisubstituted vinyl allenes in high yields by
tuning the substituents R and R1.
In summary, we have reported a new and convenient
method for the preparation of multisubstituted vinyl
allenes from 1-lithio-1,3-dienyl phosphine oxides and
aldehydes in excellent yields by the Wittig-Horner
reaction and widened the scope of iodination reactions
of R-phosphinozirconacyclopentadienes. As a whole, the
vinyl allene is composed of three molecules including two
different alkynes and one aldehyde.
SCHEME 5
Experimental Section
Typical Procedure for Preparation of 1-Iodo-dienyl
Phosphine Oxides. To a solution of Cp2ZrCl2 (365 mg, 1.25
mmol) in THF (10 mL) was added EtMgBr (2.5 mmol) at -78
°C. After the mixture was stirred for 1 h at the same
temperature, the alkynylphosphine (1.0 mmol) was added and
the reaction mixture was allowed to warm to 0 °C for 3 h. The
second alkyne (1.0 mmol) was added and stirring was contin-
ued at 50 °C for 3 h. After cooling to 0 °C, I2 (2.0 mmol) was
added and stirring was continued at room temperature for 1
h. Then the reaction mixture was quenched with 3 N HCl and
extracted with ether. Column chromatography on silica gel
afforded 1-iodo-dienyl phosphine oxides.
(1Z,3E)-2-Butyl-3-ethyl-1-iodo-1,3-hexadienyl(diphenyl)-
phosphine Oxide (5a). Light red liquid, isolated yield 65%
8788 J. Org. Chem., Vol. 70, No. 22, 2005

Preparation of Vinyl Allenes
1
(320 mg). H NMR (CDCl3, Me4Si) δ 0.76 (t, J ) 7.2 Hz, 3H),
3JPC ) 12.4 Hz), 173.4-173.7 (m). Anal. Calcd for C33H30-
Cl2O2P2I2: C, 46.89; H, 3.58. Found: C, 46.58; H, 3.70. HRMS
calcd for M+ - CH2Cl2, C32H28O2P2I2 759.9654, found 759.9653.
Typical Procedure for Preparation of 11a and 12a. To
an Et2O (10 mL) solution of 5a (1.0 mmol) at -78 °C was added
n-BuLi (1.0 mmol). After this reaction mixture was stirred at
-78 °C for 0.5 h and quenched with 20% DCl in D2O, 11a was
obtained. If a benzaldehyde (1.2 mmol) was added to the above
reaction mixture and stirred for 1 h at -78 °C, 12a was formed
after quenching with saturated NaHCO3. Column chromatog-
raphy on silica gel afforded pure 11a and 12a.
1.01-1.30 (m, 12H), 2.09-2.18 (m, 2H), 2.26 (q, J ) 7.2 Hz,
2H), 5.16 (t, J ) 7.2 Hz, 1H), 7.44-7.85 (m, 10H); 13C NMR
(CDCl3, Me4Si) δ 12.7, 13.7, 13.8, 20.9, 22.3, 22.4, 30.7, 34.6
3
1
2
(d, JPC ) 5.6 Hz), 91.8 (d, JPC ) 87.8 Hz), 128.2 (d, JPC
)
4
4
12.4 Hz), 131.5 (d, JPC ) 1.2 Hz), 131.8 (d, JPC ) 2.5 Hz),
3
1
132.3 (d, JPC ) 9.3 Hz), 133.5 (d, JPC ) 108.8 Hz), 144.9 (d,
3JPC ) 14.4 Hz), 173.2 (d, JPC ) 6.8 Hz); HRMS calcd for
2
C24H30OPI 492.1079, found 492.1084.
Typical Procedure for Preparation of 8a and 8b. To a
solution of Cp2ZrCl2 (365 mg, 1.25 mmol) in THF (10 mL) was
added EtMgBr (2.5 mmol) or n-BuLi (2.5 mmol) at -78 °C.
After the mixture was stirred for 1 h at the same temperature,
the diynes (1.0 mmol) was added and the reaction mixture was
allowed to warm to room temperature for 3 h to give the
R-phosphinobicyclozirconacyclopentadienes 7. Then the reac-
tion mixture was quenched with 3 N HCl and extracted with
ether followed by normal workup to afford crude products,
which were purified by column chromatography on silica gel.
(2-Pentylidene-cyclohexylidenemethyl)-diphenyl-phos-
phane (8a). Colorless viscous liquid, isolated yield 80% (279
mg). 1H NMR (CDCl3, Me4Si) δ 0.89 (t, J ) 7.2 Hz, 3H), 1.31-
1.65 (m, 8H), 2.04 (q, J ) 7.2 Hz, 2H), 2.28-2.60 (m, 4H), 5.54
(t, J ) 7.2 Hz, 1H), 6.03 (s, 1H), 7.26-7.42 (m, 10H); 13C NMR
(CDCl3, Me4Si) δ 14.0, 22.4, 26.2, 26.6 (d, 4JPC ) 1.2 Hz), 27.3,
(2-Butyl-3-ethyl-1-D-hexa-1,3-dienyl)-diphenyl-phos-
phine Oxide (11a). Coloress liquid, GC yield 99%, isolated
yield 90% (331 mg). 1H NMR (CDCl3, Me4Si) δ 0.74 (t, J ) 7.2
Hz, 3H), 0.96-1.05 (m, 6H), 1.11-1.24 (br, 4H), 2.12 (q, J )
7.8 Hz, 2H), 2.19-2.29 (m, 2H), 2.63-2.68 (m, 2H), 5.67 (t, J
) 7.2 Hz, 1H), 7.40-7.81 (m, 10H); 13C NMR (CDCl3, Me4Si)
δ 13.7, 13.8, 14.2, 21.2, 21.6, 22.7, 31.1, 31.2, 115.7 (d, 1JPC
)
2
3
104.5 Hz), 128.5 (d, JPC ) 11.7 Hz), 130.9 (d, JPC ) 9.9 Hz),
131.2 (d, 4JPC ) 3.1 Hz), 132.4, 135.5 (d, 1JPC ) 103.2 Hz), 141.7
3
2
(d, JPC ) 16.7 Hz), 166.2 (d, JPC ) 2.5 Hz); HRMS calcd for
C24H30ODP 367.2175, found 367.2177.
3-Butyl-2-(diphenyl-phosphinoyl)-4-ethyl-1-phenyl-hep-
ta-2,4-dien-1-ol (12a). White solid, isolated yield 82% (387
mg). Mp 162-164 °C; 1H NMR (CDCl3, Me4Si) δ 0.54-1.14
(br, 13H), 2.06-2.29 (br, 6H), 5.43 (s, 1H), 5.57(s, 1H), 5.93-
6.04 (br, 1H), 7.03-7.64 (m, 15H); 13C NMR (CDCl3, Me4Si)
δ13.3, 13.6, 14.1, 21.1, 22.6, 23.3, 29.3, 30.9 (d, 3JPC ) 9.3 Hz),
3
1
28.7, 31.9, 32.6 (d, JPC ) 24.1 Hz), 119.4 (d, JPC ) 6.8 Hz),
3
2
125.1, 128.1, 128.3 (d, JPC ) 6.8 Hz), 132.6 (d, JPC ) 18.5
1
3
Hz), 140.0 (d, JPC ) 9.3 Hz), 141.9 (d, JPC ) 6.8 Hz), 159.1
2
2
2
(d, JPC ) 24.1 Hz); HRMS calcd for C24H29P 348.2007, found
75.4 (d, JPC ) 7.4 Hz), 126.1, 126.3, 127.6, 128.1 (d, JPC
)
2
1
348.2009.
12.4 Hz), 128.4 (d, JPC ) 12.4 Hz), 129.7 (d, JPC ) 93.3 Hz),
131.4 (d, JPC ) 10.5 Hz), 131.5, 131.8 (d, JPC ) 10.5 Hz),
132.2, 132.8, 135.7 (d, JPC ) 100.1 Hz), 138.7 (d, JPC ) 13.0
Hz), 143.5. Anal. Calcd for C31H37O2P: C, 78.78; H, 7.89.
Found: C, 78.62; H, 8.01. HRMS calcd for C31H37O2P 472.2531,
found 472.2546.
3
3
Preparation of 9a, 10a, and 10b. The R-phosphinobicy-
clozirconacyclopentadienes 7a or 7b were prepared according
to the above-mentioned procedure. 7a was treated with I2 (2
mmol) for 1 h at room temperature to give 9a. 7b was treated
with I2 (4 mmol) for 1 h at room temperature to give 10b. When
7a was first treated with I2 (2 mmol) for 1 h, followed by
addition of CuCl (1 mmol) and I2 (1 mmol) with stirring for 1
h, 10a was obtained by the normal purification processes.
Iodo-(2-pentylidene-cyclohexylidene)-methyl(diphe-
nyl)phosphine Oxide (9a). Light red viscous liquid, isolated
yield 60% (294 mg). 1H NMR (CDCl3, Me4Si) δ 0.90 (t, J ) 6.9
Hz, 3H), 1.37-1.59 (m, 8H), 2.11 (q, J ) 6.9 Hz, 2H), 2.33 (t,
J ) 5.7 Hz, 2H), 3.00-3.04 (m, 2H), 5.35 (t, J ) 7.5 Hz, 1H),
7.44-7.84 (m, 10H); 13C NMR (CDCl3, Me4Si) δ 14.0, 22.5, 27.0,
1
2
Typical Procedure for Preparation of Vinyl Allenes.
To an Et2O (10 mL) solution of 1-iodo-1,3-dienyl phosphine
oxide (1.0 mmol) at -78 °C was added n-BuLi (1.0 mmol). After
this reaction mixture was stirred at -78 °C for 0.5 h, an
aldehyde (1.2 mmol) was added and stirred for 1 h at this
temperature. Then t-BuOK (1 mmol) was added at -78 °C and
stirred for 0.5 h at room temperature. The reaction mixture
was quenched with saturated NaHCO3 and extracted with
ether. Column chromatography on silica gel afforded vinyl
allenes.
(3-Butyl-4-ethyl-hepta-1,2,4-trienyl)-benzene (13a). Col-
orless liquid, isolated yield 85% (216 mg). 1H NMR (CDCl3,
Me4Si) δ 0.89 (t, J ) 7.2 Hz, 3H), 0.94 (t, J ) 7.5 Hz, 3H), 1.03
(t, J ) 7.5 Hz, 3H), 1.31-1.52 (m, 4H), 2.12-2.32 (m, 6H),
5.47 (t, J ) 7.2 Hz, 1H), 6.33 (s, 1H), 7.13-7.29 (m, 5H); 13C
NMR (CDCl3, Me4Si) δ 14.0, 14.4, 14.5, 21.6, 22.8, 23.1, 29.2,
30.3, 96.8, 111.4, 126.5, 126.6, 127.5, 128.6, 135.5, 136.3, 206.5;
HRMS calcd for C19H26 254.2035, found 254.2023.
3
1
27.1, 28.0, 29.5, 31.4, 36.9 (d, JPC ) 6.2 Hz), 85.5 (d, JPC
)
4
3
89.6 Hz), 128.1 (d, JPC ) 1.9 Hz), 128.3 (d, JPC ) 12.4 Hz),
4
2
131.9 (d, JPC ) 3.1 Hz), 132.2 (d, JPC ) 46.4 Hz), 133.6 (d,
1JPC ) 108.2 Hz), 144.9 (d, JPC ) 12.4 Hz), 171.9 (d, JPC
)
3
2
7.4 Hz); HRMS calcd for C24H28OPI 490.0923, found 490.0916.
Iodo-[2-(1-iodopentylidene)cyclohexylidene]methyl-
(diphenyl)phosphine oxide (10a). Light red viscous liquid,
1
isolated yield 55% (339 mg). H NMR (CDCl3, Me4Si) δ 0.91
(t, J ) 7.2 Hz, 3H), 1.33-1.63 (br, 6H), 1.82-1.90 (m, 2H),
2.00-3.88 (br, 6H), 7.44-7.98 (m, 10H); 13C NMR (CDCl3, Me4-
3
Si) δ 13.9, 21.8, 28.2, 29.5, 31.3, 33.5, 36.6 (d, JPC ) 5.6 Hz),
Acknowledgment. This work was partially sup-
ported by National Natural Science Foundation of China
(20172003, 20232010, 20328201), the Major State Basic
Research Development Program (G2000077502-D), and
Dow Corning Corporation. Cheung Kong Scholars Pro-
gram, Qiu Shi Science & Technologies Foundation, and
BASF are gratefully acknowledged.
1
4
39.8, 89.7 (d, JPC ) 87.8 Hz), 100.7 (d, JPC ) 1.9 Hz), 128.1,
2
2
128.2, 128.4, 131.9, 132.3 (d, JPC ) 9.8 Hz), 132.5 (d, JPC
)
1
3
9.3 Hz), 133.6 (d, JPC ) 5.3 Hz), 151.3 (d, JPC ) 12.1 Hz),
173.4 (d, 2JPC ) 8.7 Hz); HRMS calcd for C24H27OPI2 615.9889,
found 615.9873.
1,2-Bis(1-iodo-1-(diphenylphosphinoyl)methylene)-
cyclohexane (10b). Light red solid, isolated yield 35% (266
mg). Mp 152-154 °C; 1H NMR (CDCl3, Me4Si) δ 1.58 (t, J ) 9
Hz,2H), 1.87-2.22 (m, 4H), 4.06 (d, J ) 12 Hz, 2H), 5.29 (s,
2H), 7.41-7.91 (m, 20H); 13C NMR (CDCl3, Me4Si) δ 29.1, 37.3
(d, JPC ) 4.9 Hz), 53.5, 88.6 (dd, JPC ) 85.9 Hz, JPC ) 1.9
Hz), 128.4 (d, 3JPC ) 13.0 Hz), 131.0 (d, 1JPC ) 109.4 Hz), 132.1
(d, 1JPC ) 109.4 Hz), 132.2 132.3 (d, 3JPC ) 12.4 Hz), 132.5 (d,
Supporting Information Available: 1H and 13C NMR
spectra of all new products. This material is available free of
charge via the Internet at http://pubs.acs.org.
3
1
4
JO051178C
J. Org. Chem, Vol. 70, No. 22, 2005 8789