Preparation and nickel-catalyzed coupling reactions of divinylic selenides

Article abstract of DOI:10.1016/S0040-4039(02)01773-2

The preparation of divinylic selenides by the reaction of selenium bis-phosphonate with aromatic aldehydes is described. The nickel-catalyzed cross coupling of the divinylic selenides with Grignard reagents was also studied.

Full text of DOI:10.1016/S0040-4039(02)01773-2

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 43 (2002) 7517–7520
Preparation and nickel-catalyzed coupling reactions of
divinylic selenides
Claudio C. Silveira,* Paulo Cesar S. Santos and Antonio L. Braga
Departamento de Qu´ımica, Universidade Federal de Santa Maria, Caixa Postal 5001, 97105-900 Santa Maria, RS, Brazil
Received 30 July 2002; revised 20 August 2002; accepted 23 August 2002
Abstract—The preparation of divinylic selenides by the reaction of selenium bis-phosphonate with aromatic aldehydes is
described. The nickel-catalyzed cross coupling of the divinylic selenides with Grignard reagents was also studied. © 2002 Elsevier
Science Ltd. All rights reserved.
Vinylic selenides are useful intermediates for the synthe-
sis of several compounds and much attention has been
devoted to their preparation and to their synthetic
utilization.1 From the several methods for the synthesis
of vinylic selenides, the Wittig or Wittig–Horner reac-
tions constitute one of the most useful.2 We have
recently reported convenient methods for the synthesis
of vinylic selenides by Wittig or Wittig–Horner routes.3
In this way, we envisioned that by using divinylic
selenides on these coupling reactions, both organyls
linked to selenium could eventually be transferred. A
search on the literature shows that divinylic selenides
have been prepared by the reaction of vinyl selenide
anions with (E)- or (Z)-b-bromo styrenes.7 The vinyl
selenide anions were generated in situ by the cleavage
of methylselenium styryls with lithium methyl selenide
anion in DMF or with sodium in DMA.7 By this route,
E/E-, E/Z- or Z/Z-bis-styryl selenides could be acces-
sible, although in moderate yields. Z,Z-Distyryl sele-
nide has also been prepared by reacting potassium
diselenide and phenylacetylene in 82% yield.8 However,
the synthesis of divinylic selenides by the Wittig–
Horner route has not been properly studied, since only
one example was described,9 by the reaction of the
corresponding selenium bis-phosphonate 1 with benz-
aldehyde, Scheme 1. In this way, we decided to explore
the full scope of this method and the application of the
prepared divinylic selenides in the cross-coupling reac-
tion with Grignard reagents catalyzed by Ni(II)-phos-
phines, as presented in Scheme 1.
From the many applications of this class of com-
pounds, the cross coupling reaction with Grignard
reagents catalyzed by Ni(II) constitutes one of the most
useful. The reaction of vinylic selenides with PhMgBr
and n-BuMgBr, catalyzed by NiCl2(Ph3P)2 or
Ni(dppp)Cl2, to give the corresponding cross-coupling
products has been described. These reactions proceeded
with retention of configuration and in good yields.4 A
chemoselective coupling reaction was described by the
reaction of (E)- and (Z)-(phenylthio)ethenyl methyl
selenides with Grignard reagents, catalyzed by Ni(II)
species, in which only the selenium organyl is removed.
The stereospecific carbonꢀselenium bond cleavage can
be achieved by the choice of the appropriate Ni cata-
lyst.5 The coupling of vinylic selenides has also been
applied to the synthesis of allyl silanes by reaction with
trimethylsilylmagnesium chloride and NiCl2(Ph3P)2 or
PdCl2(Ph3P)2 catalysis.6 However, in all these methods,
when the coupling reaction is performed, one of the
two organic moieties linked to the selenium atom,
which is usually a phenyl or a methyl group, is lost.
Keywords: coupling reactions; nickel and compounds; selenium and
compounds; vinylic selenides.
* Corresponding author. Tel./fax: +55-55-2208754; e-mail: silveira@
quimica.ufsm.br
Scheme 1.
0040-4039/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4039(02)01773-2

7518
C. C. Sil6eira et al. / Tetrahedron Letters 43 (2002) 7517–7520
The next step was the cross-coupling reaction of
divinylic selenides with Grignard reagents to find out if
the behavior of these species would be the same as a
normal vinylic selenide and if both styryl groups could
be transferred to the product. We started trying the
reaction of distyryl selenide 2a with PhMgBr in a
reaction catalyzed by NiCl2(Ph3P)2 in benzene as the
solvent. Using 10 mol% of catalyst, total consumption
of the starting material was observed (although 5 mol%
or less are also equally effective), and the product was
isolated in 62% yield (entry 1, Table 2), along with 35%
of the 1,4-diphenyl butadiene. A quite different behav-
ior was observed in the reaction of 2a with C8H17MgBr,
since an incomplete reaction occurred and the desired
product was isolated in low yield. Total disappearance
(as judged by TLC) of 2a was observed using an
equimolar amount of the catalyst after 3 h of reaction,
at room temperature, and the corresponding product 3a
was isolated after column chromatography in 63%
yield.12 However, we observed that, by using 1 equiv. of
LiCl, the reaction could be performed to completion
using 10 mol% of NiCl2(Ph3P)2, and the product was
isolated in 68% yield. As we expected, we were able to
transfer to the product both organyls linked to the
selenium atom, which is removed at the end of the
reaction as black selenium by filtration in Celite. The
reaction was then extended to some other bis-vinylic
selenides 2c and 2g. In all cases, moderate to good
yields of the desired products 3a–f were isolated, but
the formation of the 1,4-diaryl-1,3-butadienes could not
be avoided, even after several modifications that we
made in the experimental procedure (Table 2). Fortu-
nately, these species can be very easily removed by
column chromatography (see experimental).13 As
expected, in all these coupling reactions, only E-vinylic
products were obtained.
For the synthesis of divinylic selenides by the Wittig–
Horner route, the first step was the preparation of the
selenium bis-phosphonate 1. This intermediate was
obtained in 71% isolated yield by the addition of a
THF solution of the iodomethylphosphonate to Na2Se
(conveniently generated in situ by the reduction of
selenium with NaBH4 in ethyl alcohol),10 followed by 2
h at reflux.11 The preparation of the divinylic selenides
2a–g was performed by treatment of the bis-phospho-
nate 1 with NaH as a base, in THF, followed by the
addition of the appropriate aryl aldehyde, according to
Scheme 1. The results of this reaction are summarized
in Table 1. In some examples good results could only
be obtained by the use of HMPA as a co-solvent.12
Unfortunately, the reaction was successful only to aro-
matic aldehydes. 1H NMR analysis indicated the
almost exclusive formation of the (E,E)-isomers in all
examples studied. In some examples, a very small
1
amount of Z-isomer could be detected by H and 13C
NMR, easily removed by column chromatography or
during recrystallization.
Table 1. Divinylic selenides 2a–g prepared according to
Scheme 1
Entry Aldehyde
Product Yield (%)a Mp (°C)c,d
1
2
3
4
5
6
7
C6H5CHO
3,4-OCH2O-C6H3CHO
4-CH3O-C6H4CHO
3,4-Di-(CH3O)-C6H3CHO 2d
C6H5CHꢁCHCHO
4-Cl-C6H4CHO
2a
2b
2c
75b
87b
54
45–47
88–90
106–108
93–95
86–87
126–128
74–76
72b
61b
53b
51
2e
2f
2g
4-CH3-C6H4CHO
In summary, we describe a convenient preparation of
divinylic selenides by a Wittig–Horner route and
observe that these species participate conveniently in
nickel-catalyzed cross-coupling reactions with Grignard
reagents, with total retention of configuration.
a Isolated yields after column chromatography.
b HMPA (0.5–1 mL) used as co-solvent.
c From hexane.
d All products were fully characterized by spectroscopic methods.
Table 2. Cross-coupling products 3 prepared according to Scheme 1
Entry
Ar
R
3
Yield 4 (%)
Yield (%)
Mp (°C)
122–124a
1
2
3
4
5
6
C6H5
C6H5
4-CH3C6H4
4-CH3C6H4
4-CH3OC6H4
4-CH3OC6H4
C6H5
C8H17
C6H5
C8H17
C6H5
C8H17
3a
3b
3c
3d
3e
3f
62
68
56
59
86
62
35
23
24
18
10
12
b
–
117–119c
b
–
133–135d
b
–
a Mp 123–124°C.14
b Oil.
c Mp 116–118°C.15
d Mp 135°C.15

C. C. Sil6eira et al. / Tetrahedron Letters 43 (2002) 7517–7520
7519
Acknowledgements
mL; see text and Table 1). The reaction mixture was
refluxed for 2 h, cooled to room temperature, water was
added and extracted with ethyl acetate, the organics dried
over MgSO4 and the solvent was removed under vacuum.
The residue was purified by silica gel column chromatog-
raphy, eluting with hexane or mixtures of hexane/ethyl
acetate. Selected spectroscopic data. Compound 2a:9 1H
NMR (200 MHz, CDCl3): l 6.86 (d, 2H, J=15.8 Hz),
7.11 (d, 2H, J=15.8 Hz), 7.20–7.40 (m, 10H); 13C NMR
(50 MHz, CDCl3): l 117.7, 125.9, 127.6, 128.6, 134.7,
136.9; GC/MS m/z 286 (M++1, 9%), 205, 190, 128, 102,
The authors thank the following agencies for financial
support: FAPERGS, CAPES and CNPq. We thank
Professor H. A. Stefani for providing some mass spec-
tra and Professor B. H. Lipshutz for helpful
discussions.
References
1
76 (100%). Compound 2c: H NMR (200 MHz, CDCl3):
1. Comasseto, J. V.; Ling, L. W.; Petragnani, N.; Stefani, H.
A. Synthesis 1997, 373–403.
l 3.80 (s, 6H), 6.81 (d, 2H, J=15.8 Hz), 6.85 (d, 4H,
J=8.7 Hz), 6.96 (d, 2H, J=15.8 Hz), 7.28 (d, 4H, J=8.6
Hz); 13C NMR (50 MHz, CDCl3): l 55.3, 114.1, 114.9,
127.3, 130.0, 134.7, 159.3; GC/MS m/z 344 (M++1, 2.4%),
266 (100%), 251, 235, 220, 207, 158, 134, 121, 91. Com-
pound 2f: 1H NMR (200 MHz, CDCl3): l 6.81 (d, 2H,
J=15.8 Hz), 7.11 (d, 2H, J=15.8 Hz), 7.20–7.35 (m, 8H);
13C NMR (50 MHz, CDCl3): l 118.3, 127.2, 128.9, 133.4,
133.6, 135.3; GC/MS m/z 354 (M+, 3%), 274, 239, 204,
2. For a review, see: Silveira, C. C.; Perin, G.; Jacob, R. G.;
Braga, A. L. Phosphorus Sulfur Silicon 2001, 172, 55–100.
3. (a) Silveira, C. C.; Boeck, P.; Braga, A. L. Tetrahedron
Lett. 2000, 41, 1867–1869; (b) Silveira, C. C.; Perin, G.;
Boeck, P.; Braga, A. L.; Petragnani, N. J. Organomet.
Chem. 1999, 584, 44–47; (c) Silveira, C. C.; Perin, G.;
Braga, A. L.; Dabdoub, M. J.; Jacob, R. G. Tetrahedron
1999, 55, 7421–7432 and references cited therein.
4. (a) Okamura, H.; Miura, M.; Kosugi, K.; Takei, H.
Tetrahedron Lett. 1980, 21, 87–90; (b) Tingoli, M.;
Tiecco, M.; Testaferri, L.; Temperini, A.; Pelizzi, G.;
Bacci, A. Tetrahedron 1995, 51, 4691–4700; (c) Gerard, J.;
Hevesi, L. Tetrahedron 2001, 57, 9109–9121.
1
127, 101 (100%), 75. Compound 2g: H NMR (200 MHz,
CDCl3): l 2.33 (s, 6H), 6.84 (d, 2H, J=16 Hz), 7.07 (d,
2H, J=16 Hz), 7.13 (d, 4H, J=8 Hz), 7.23 (d, 4H, J=8
Hz); 13C NMR (50 MHz, CDCl3): l 21.2, 116.2, 125.9,
129.3, 134.2, 134.4, 137.5; GC/MS m/z 314 (M++1, 9.6%),
234, 219, 203, 115 (100%), 105, 91.
5. Tingoli, M.; Tiecco, M.; Testaferri, L.; Chianelli, D.
13. General procedure for the coupling reaction. Preparation of
3b: To a 25 mL flask under argon was added the catalyst
[NiCl2(PPh3)2; 0.035 g, 0.05 mmol)], LiCl (0.021 g, 0.5
mmol; for aliphatic Grignard) and dry benzene (3 mL),
followed by C8H17MgBr (0.5 mL, 0.5 mmol, 1 M solu-
tion). After 15 min, more of the Grignard reagent (1.5
mL, 1.5 mmol) and 2a (0.143 g, 0.5 mmol) in dry benzene
(3 mL) was added. The reaction mixture became dark
and was stirred for 3 h at rt, followed by the addition of
water. The solids formed were filtered under Celite, wash-
ing with ethyl acetate. The organics were washed with an
aqueous saturated solution of NH4Cl, dried over MgSO4,
the solvent removed under vacuo and the residue was
purified by silica gel column chromatography, using hex-
ane as the eluent, first eluting the coupling product 3b
(1.146 g, 68% yield), followed by the butadiene. Selected
Gazz. Chim. Ital. 1991, 121, 59–61.
6. Hevesi, L.; Hermans, B.; Allard, C. Tetrahedron Lett.
1994, 36, 6729–6730.
7. Testaferri, L.; Tiecco, M.; Tingoli, M.; Chianelli, D.
Tetrahedron 1986, 42, 63–69.
8. Potapov, V. A.; Amosova, S. V.; Zhnikin, A. R.; Shes-
takova, V. Yu. Sulfur Lett. 1995, 19, 55–58.
9. Comasseto, J. V.; Petragnani, N. J. Organomet. Chem.
1978, 152, 295–304.
10. This reagent, although commercially available from Alfa
Aesar, it is moisture sensitive and quite expensive.
11. Preparation of the selenium bis-phosphonate 1:9 In a 100
mL round-bottom flask equipped with an addition funnel
and reflux condenser under argon charged with selenium
(1.11 g, 14 mmol) and absolute ethyl alcohol (40 ml) was
added dropwise a solution of NaBH4 (1.26 g, 33 mmol) in
water (10 ml). After the addition of reagents was com-
plete, the mixture was refluxed until the dissolution of
selenium was complete. The solution was cooled to room
1
spectroscopic data. Compound 3b: H NMR (200 MHz,
CDCl3): l 0.85–0.90 (m, 3H), 1.2–1.5 (m, 12H), 2.19 (q,
2H, J=6.8 Hz), 6.20 (dt, 1H, J=15.8 and 6.4 Hz), 6.38
(d, 1H, J=15.8 Hz), 7.10–7.40 (m, 5H) (data in accor-
dance with Ref. 17); 13C NMR (50 MHz, CDCl3): l 14.0,
22.6, 29.2, 29.3, 29.4, 29.5, 31.9, 33.0, 125.9, 126.7, 128.4,
129.7, 131.1, 137.9; IR (film, cm−1) 2923, 2852, 1494,
1465; GC/MS m/z 216 (M+, 14%), 117, 104, 71, 57, 43
(100%). (1E,3E)-1,4-Diphenyl-1,3-butadiene: mp 148–
150°C (Lit.16 mp 151–153°C). Compound 3c: mp 117–
119°C (Lit.15 mp 116–118°C); 1H NMR (200 MHz,
CDCl3): l 2.34 (s, 3H), 7.0–7.6 (m, 11H); 13C NMR (50
MHz, CDCl3): l 21.2, 126.4, 127.4, 127.7, 128.7, 129.4,
133.6, 137.5; GC/MS m/z 194 (M+, 7%), 179, 115, 28
(100%); IR (KBr, cm−1) 3022, 2914, 1593, 1509, 1466,
968. (1E,3E)-1,4-Di-p-tolyl-1,3-butadiene: mp 202–
204°C. Compound 3e: mp 133–135°C (Lit.15 mp 135°C);
1H NMR (200 MHz, CDCl3): l 3.83 (s, 3H), 6.90 (d, 2H,
J=8.8 Hz), 7.0–7.5 (m, 9H); 13C NMR (50 MHz,
temperature and
a solution of the iodomethyl(di-
ethylphosphonate) (7.78 g, 28 mmol) in THF (40 ml) was
added. The mixture was refluxed for 2 h, cooled to room
temperature, water was added and then extracted with
ethyl acetate. The organics were washed with an aqueous
saturated solution of NH4Cl, dried over MgSO4 and the
solvent removed under vacuum. The residue was purified
by column chromatography, eluting with hexane/ethyl
acetate (7:3) or vacuum distillation (bp 250°C/0.5
mmHg). Yield: 3.78 g, 71%.
12. General procedure for the preparation of the divinylic
selenides 2: To a 25 ml round-bottom flask, under argon
and equipped with a reflux condenser, was added THF (5
mL), NaH (0.060 g, 2.4 mmol), a solution of the selenium
bis-phosphonate 1 (0.45 g, 1.2 mmol) in THF (4 mL) and
after 10 min the aldehyde (2 mmol) and HMPA (0.5–1

7520
C. C. Sil6eira et al. / Tetrahedron Letters 43 (2002) 7517–7520
15. Ward, W. J., Jr.; McEwen, W. E. J. Org. Chem. 1990, 55,
CDCl3): l 55.3, 114.1, 126.2, 127.1, 127.7, 128.2, 128.6,
130.1, 137.6, 159.3; GC/MS m/z 210 (M+, 6%), 165, 152,
40, 28 (100%); IR (KBr, cm−1) 2961, 1509, 1264, 1173,
1029. (1E,3E)-1,4-Di-p-anisoyl-1,3-butadiene: mp 221–
223°C (Lit.18 224–226°C).
493–500.
16. Commercially available from Sigma-Aldrich Co.
17. Fleming, I.; Newton, T. W. J. Chem. Soc., Perkin Trans.
1 1984, 119–124.
14. Babudri, F.; Farinola, G. M.; Naso, F.; Panessa, D. J.
Org. Chem. 2000, 65, 1554–1557.
18. Abu-Yousef, I. A.; Hay, A. S. Synth. Commun. 1999, 29,
2915–2922.