Hydrozirconation of alkynyl sulfoxides: The reactions of zirconated vinyl sulfoxide intermediates

Article abstract of DOI:10.1016/S0040-4020(00)00843-7

Alkynyl sulfoxides react with Cp₂Zr(H)Cl in THF at room temperature to give the α-zirconated and β-zirconated vinyl sulfoxides, which react with a wide range of electrophiles to give several types of di- or trisubstituted olefins, such as Z-vinyl sulfoxides and α- or β-halo vinyl sulfoxides. (C) 2000 Elsevier Science Ltd.

Full text of DOI:10.1016/S0040-4020(00)00843-7

TETRAHEDRON
Pergamon
Tetrahedron 56 (2000) 8921±8925
Hydrozirconation of Alkynyl Sulfoxides: the Reactions of
Zirconated Vinyl Sulfoxide Intermediates
a,b,²
Ping Zhong,a,b Xian Huanga,b, and Meng Ping-Guo
*
aDepartment of Chemistry, Zhejiang University (Campus Xixi), Hangzhou, 310028, People's Republic of China
bLaboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Science, Shanghai, 200032,
People's Republic of China
Received 16 June 2000; revised 29 August 2000; accepted 14 September 2000
AbstractÐAlkynyl sulfoxides react with Cp2Zr(H)Cl in THF at room temperature to give the a-zirconated and b-zirconated vinyl sulf-
oxides, which react with a wide range of electrophiles to give several types of di- or trisubstituted ole®ns, such as Z-vinyl sulfoxides and a- or
b-halo vinyl sulfoxides. q 2000 Elsevier Science Ltd. All rights reserved.
Unsaturated sulfoxides have been widely used as building
blocks in organic chemistry,1±5 and a few routes to such
compounds are known.6±10 For example, oxidation of
vinyl thioethers leads to sulfoxides,6 the Horner±Wittig pro-
cedure using carbonyl compounds and sul®nyl methyl-
phosphonate anions leads to a mixture of (E)- and (Z)-1-
alkenyl sulfoxides.7 (E)- and (Z)-2-bromovinyl phenyl sulf-
oxides react with cuprates in a cross-coupling process
giving the corresponding 1-alkenyl sulfoxides.8 Reaction
of 1-alkynyl p-tolyl sulfoxides with lithium aluminum
hydride in THF at 2908C proceeds to give (E)-1-alkenyl
sulfoxides9 (E)-1-Alkenylmagnesium bromides react with
chiral menthyl sul®nate esters to produce chiral (E)-1-
alkenyl sulfoxides.10 But the starting materials such as
vinyl thioethers, (Z)-2-bromovinyl phenyl sulfoxides, and
(Z)-1-alkenylmagnesium bromides are not easily available.
synthesized containing elements such as selenium and
zirconium,12 tellurium and zirconium,13 silicon and zir-
conium,14 tin and zirconium,15 zinc and zirconium,16 and
boron and zirconium.17 Recently we have reported the
synthesis of sulfonylsubstituted alkenylzirconocene
compounds via the hydrozirconation of internal acetylenic
sulfones.18 We now report that we have successfully synthe-
sized sul®nylsubstituted alkenylzirconocene compounds via
the hydrozirconation of alkynyl sulfoxides, which affords
the corresponding Z-vinylsulfoxides in high yields by a
proton quench (Scheme 1).
Acetylenic sulfoxides 1a±f were synthesized in good yield
according to the method of Villar.11 Hydrozirconation of the
acetylenic sulfoxides with 1.1 equiv. of Cp2Zr(H)Cl in THF
for 30 min at room temperature gave a clear yellow solution.
Z-Vinyl sulfoxides 2a±f were obtained after hydrolysis
(Table 1). The con®guration was assigned to all compounds
(2) by the coupling constant (Jˆ11.0 Hz) for the vinyl
Acetylenic sulfoxides have been used extensively in organic
synthesis as activated acetylene equivalents.11 Surprisingly,
little attention has been paid to their hydrometalation
reactions. On the other hand, via the hydrozirconation of
alkynes, many bifunctional ethenyl reagents have been
1
protons in the H NMR spectra. The signals resulting from
the E-isomers were not found in any case, indicating that the
reactions were stereospeci®c.
Scheme 1. 1a: RˆPh, R0ˆPh; 1b: Rˆn-C5H11; R0ˆPh; 1c: Rˆn-C4H9; R0ˆPh; 1d: RˆPh, R0ˆ4-MeC6H4; 1e: Rˆn-C5H11; R0ˆ4-MeC6H4; 1f: Rˆn-C4H9;
R0ˆ4-MeC6H4.
Keywords: sulfoxides; alkynes; alkenes; zirconium; compounds.
* Corresponding author. Fax: 186-571-8807077; e-mail: xhuang@mail.hz.zj.cn
Permanent address: Department of Chemistry, Yichun Teacher's Collegy, Yichun 33600, People's Republic of China.
²
0040±4020/00/$ - see front matter q 2000 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)00843-7

8922
P. Zhong et al. / Tetrahedron 56 (2000) 8921±8925
Table 1. Synthesis of Z-vinylsulfoxides 2a±f
On the other hand, the hydrozirconation of 1-arylsul®nyl-2-
alkylethynes 1b,1c,1e and 1f results in the formation of
mixtures of the regioisomers a-zirconated 9 and b-zirco-
nated vinylsulfoxides 10 that by reaction with D2O, I2 or
NBS, afforded a mixture of 11 and 12 as depicted in Scheme
3.
Entry
R
R0
Yielda (%)
2a
2b
2c
2d
2e
2f
Ph
Ph
Ph
Ph
78
73
80
74
70
77
n-C5H11
n-C4H9
Ph
n-C5H11
n-C4H9
4-MeC6H4
4-MeC6H4
4-MeC6H4
The complete regioselectivity to the hydrozirconation of
compounds 1a, 1d (RˆPh) could be explained on the
basis of simple steric and conventional electronic effects
(phenyl is a large group, the beta carbon of sulfoxide is
the most electrophilic). However, the mixtures of regio-
isomers (9, 10) was formed when R was the smaller group
(Rˆn-alkyl).
a Isolated yield.
Sul®nylsubstituted alkenylzirconocene compounds were
found to react with various electrophiles (Table 2). The
total inversion of regioselectivity was observed when a
phenyl group is linked to the triple bond as in the (arylsul-
®nyl)phenylacetylene 1a and 1d. In this case, the a-zirco-
nated sul®nylalkenes 3 were the intermediates formed and
after treatment with D2O, I2 or NBS, the compounds 4 were
isolated as sole products in 57%±73% (Scheme 2).
In conclusion, the hydrozirconation strategy provides a
direct route to (Z)-1-alkenyl sulfoxides from acetylenic sulf-
oxides. The method has some attractive advantages such
as readily available starting materials, high yields, mild
Table 2. Vinyl sulfoxides obtained from alkynyl sulfoxides

P. Zhong et al. / Tetrahedron 56 (2000) 8921±8925
8923
Scheme 2. RˆPh, 4-MeC6H4; XˆD, I, Br.
Scheme 3. 11a, 12a: Rˆn-C4H9; R0ˆPh, XˆD; 11b, 12b: Rˆn-C5H11; R0ˆ4-MeC6H4, XˆD; 11c, 12c: Rˆn-C5H11; R0ˆ4-MeC6H4, XˆI; 11d, 12d:
Rˆn-C5H11; R0ˆ4-MeC6H4, XˆBr; 11e, 12e: Rˆn-C4H9; R0ˆ4-MeC6H4, XˆBr.
Scheme 4.
reaction conditions and straightforward access to exclusive
(Z)-con®gured products. Furthermore, the hydrozirconation
strategy provides a direct route to trisubstituted alkenes
from acetylenic sulfoxides. For example, treatment of alky-
nyl sulfoxide 1a with Cp2Zr(H)Cl, followed by treatment
with alkynylphenyliodonium tosylates in the presence of
Pd(PPh3)4, affords compound 13 in 54% (Scheme 4).
reaction mixture was stirred for about 30 min until the pre-
cipitate completely disappeared. To the resulting clear green
solution was then added 0.2 ml water (or 0.2 ml D2O), the
mixture was stirred for 1 h at ambient temperature. The
solvent was removed by rotary evaporator under reduced
pressure to give a crude oil, which was puri®ed by prepara-
tive TLC (silica gel, hexane/AcOEtˆ10:1) to give 2a±f,
4a±b, 11a±b and 12a±b, respectively.
1
2a.6 Yellow oil. H NMR (CDCl3, d ppm): 7.05±7.55 (m,
Experimental
10H, C6H5), 6.95 (d, Jˆ10.5 Hz, 1H, vCH), 6.22 (d, Jˆ
10.5 Hz, 1H, vCH). IR n (cm21): 3090, 1600, 1490, 1040.
Anal. Calcd for C14H12OS: C, 73.65; H, 5.30%. Found: C,
73.87; H, 5.37%.
General remarks
1H NMR spectra were recorded on a Bruker AM-300 spec-
trometer with TMS as internal standard in CDCl3. Chemical
shifts were reported in parts per million (d, ppm). Mass
spectra were determined using a Finigan 8230 mass spectro-
meter. IR spectra were obtained in neat capillary cell on a
Shimadzu IR-408 instrument. The reaction were carried out
in pre-dried glassware (1508C, 4 h) and cooled under a
stream of dry nitrogen. All solvents were dried, deoxy-
genated and redistilled before use. Acetylenic sulfoxides
and alkynylphenyliodonium tosylates were prepared
according to the literature methods respectively.11,19
2b.10 Yellow oil. 1H NMR (CDCl3, d ppm): 7.30±7.60 (m,
5H, C6H5), 5.95±6.20 (m, 2H, vCH), 2.20±2.40 (m, 2H,
vCHCH2), 1.15±1.65 (m, 6H, CH2), 0.90 (t, Jˆ6.5 Hz, 3H,
CH3). IR n (cm21): 3090, 3020, 2970, 2870, 1590, 1490,
1025. Anal. Calcd for C13H18OS: C, 70.23; H, 8.16%.
Found: C, 70.56; H, 8.12%.
1
2c.8 Yellow oil. H NMR (CDCl3, d ppm): 7.40±7.65 (m,
5H, C6H5), 6.10±6.27 (m, 2H, vCH), 2.30±2.50 (m, 2H,
vCHCH2), 1.12±1.62 (m, 4H, CH2), 0.87 (t, Jˆ6.5 Hz, 3H,
CH3). IR n (cm21): 3090, 3020, 2970, 2870, 1590, 1485,
1090, 1025. Anal. Calcd for C12H16OS: C, 69.19; H, 7.74%.
Found: C, 69.54; H, 7.79%.
General procedure for the synthesis of Z-vinylsulfoxides
2a±f, 4a±b, 11a±b and 12a±b
To a freshly prepared suspension of Cp2Zr(H)Cl (1.5 mmol)
in THF (6 ml) at rt was added a solution of acetylenic sulf-
oxides 1 (1.36 mmol) in THF (0.5 ml) under nitrogen, the
1
2d.20 Yellow solid, Mp: 60±618C (lit.17, mp 60±618C). H
NMR (CDCl3, d ppm): 7.20±7.55 (m, 9H, C6H5, C6H4),

8924
P. Zhong et al. / Tetrahedron 56 (2000) 8921±8925
1
7.02 (d, Jˆ10.5 Hz, 1H, vCH), 6.30 (d, Jˆ10.5 Hz, 1H,
vCH), 2.26 (s, 3H, CH3). IR n (cm21): 3100, 1610, 1495,
1450, 1040, 1015. Anal. Calcd for C15H14OS: C, 74.34; H,
5.82%. Found: C, 74.57; H, 5.79%.
4c. Yellow oil. H NMR (CDCl3, d ppm): 7.30±7.50 (m,
10H, C6H5), 7.10 (s, 1H, vCH). IR n (cm21): 3080, 1595,
1485, 1085, 1045, 1020. MS: m/z 354 (M1). Anal. Calcd for
C14H11IOS: C, 47.47; H, 3.13%. Found: C, 47.87; H, 3.09%.
2e.9 Yellow oil. 1H NMR (CDCl3, d ppm): 7.10 (d, Jˆ8 Hz,
2H), 7.65 (d, Jˆ8 Hz, 2H), 6.35 (m, 1H, vCH), 6.05 (d,
Jˆ10.5, 1H, vCH), 2.40 (s, 3H, CH3), 1.95±2.35 (m, 2H,
vCHCH2), 1.05±1.80 (m, 6H, CH2), 0.92 (br, t, Jˆ6 Hz,
3H, CH3). IR n (cm21): 2980, 1625, 1600, 1495, 1090, 1020.
Anal. Calcd for C14H20OS: C, 71.14; H, 8.52%. Found: C,
71.51; H, 8.48%.
4d. Yellow solid, Mp: 78±808C. 1H NMR (CDCl3, d ppm):
7.50 (d, Jˆ8 Hz, 2H), 7.57 (d, Jˆ8 Hz, 2H), 7.30±7.40 (m,
5H, C6H5), 7.33 (s, 1H, vCH), 2.20 (s, 3H, CH3). IR n
(cm21): 3060, 1600, 1495, 1450, 1078, 1020. MS: m/z 368
(M1, 2.50), 202 (100). Anal. Calcd for C15H13IOS: C, 48.93;
H, 3.56%. Found: C, 49.16; H, 3.69%.
1
4e. Yellow oil. H NMR (CDCl3, d ppm): 7.18±7.65 (m,
2f.9 Yellow oil. 1H NMR (CDCl3, d ppm): 7.10 (d, Jˆ8 Hz,
2H), 7.70 (d, Jˆ8 Hz, 2H), 5.90±6.30 (m, 2H, vCH), 2.40
(s, 3H, CH3), 1.90±2.30 (m, 2H, vCHCH2), 1.10±1.70 (m,
4H, CH2), 0.90 (br t, Jˆ6 Hz, 3H, CH3). IR n (cm21): 2980,
1620, 1598, 1495, 1090, 1040, 1020. Anal. Calcd for
C13H18OS: C, 70.23; H, 8.16%. Found: C, 69.94; H, 8.10%.
9H, C6H5, C6H4), 7.06 (s, 1H, vCH), 2.28 (s, 3H, CH3). IR
n (cm21): 3065, 1605, 1497, 1450, 1080, 1020. MS: m/z 321
(M11). Anal. Calcd for C15H13BrOS: C, 56.08; H, 4.08%.
Found: C, 56.43; H, 4.13%.
1
11c and 12c. Yellow oil. H NMR (CDCl3, d ppm): 7.25±
7.65 (m, 4H, C6H4), 7.06 (t, Jˆ6.5 Hz, 0.43H, vCH), 6.60
(s, 0.57H, vCH), 2.30 (s, 3H, CH3), 2.10±2.35 (m, 2H,
vCHCH2), 1.05±1.75 (m, 6H, CH2), 0.90 (br, t, Jˆ6 Hz,
3H, CH3). IR n (cm21): 2970, 1620, 1600, 1090, 1020. MS:
m/z 345 (M-17, 2.0), 218 (100). Anal. Calcd for C14H19IOS:
C, 46.42; H, 5.29%. Found: C, 46.71; H, 5.23%.
1
4a. Yellow oil. H NMR (CDCl3, d ppm): 7.05±7.60 (m,
10H, C6H5), 6.98 (s, 1H, vCH). IR n (cm21): 3080, 1595,
1485, 1085, 1045, 1020. MS: m/z 229 (M1).
1
4b.21 Yellow solid, Mp: 64±668C. H NMR (CDCl3, d
ppm): 7.50 (d, Jˆ8 Hz, 2H), 7.60 (d, Jˆ8 Hz, 2H), 7.30±
7.40 (m, 5H, C6H5), 7.10 (s, 1H, vCH), 2.25 (s, 3H, CH3).
IR n (cm21): 3070, 1610, 1495, 1445, 1040, 1018. MS: m/z
243 (M1).
11d and 12d. Yellow oil. 1H NMR (CDCl3, d ppm): 7.30±
7.66 (m, 4H, C6H4), 7.10 (t, Jˆ6.8 Hz, 0.43H, vCH), 6.55
(s, 0.57H, vCH), 2.38 (s, 3H, CH3), 2.30±2.45 (m, 2H,
vCHCH2), 1.00±1.65 (m, 6H, CH2), 0.86 (br t, Jˆ6 Hz,
3H, CH3). IR n (cm21): 2980, 1620, 1600, 1090, 1020. MS:
m/z 315 (M11). Anal. Calcd for C14H19BrOS: C, 53.34; H,
6.07%. Found: C, 53.72; H, 6.11%.
11a and 12a. Yellow oil. 1H NMR (CDCl3, d ppm): 7.20±
7.70 (m, 5H, C6H5), 6.30 (t, Jˆ6 Hz, 0.4H, vCH), 6.18 (s,
0.6H, vCH), 2.20±2.45 (m, 2H, vCHCH2), 1.10±1.60 (m,
4H, CH2), 0.85 (t, Jˆ6.5 Hz, 3H, CH3). IR n (Cm21): 3090,
3010, 2980, 2950, 2880, 1593, 1085, 1020. MS: m/z 209
(M1).
1
11e and 12e. Yellow oil. H NMR (CDCl3, d ppm): 7.30±
7.60 (m, 4H, C6H4), 6.95 (t, Jˆ6 Hz, 0.4H, vCH), 6.50 (s,
0.4H, vCH), 2.26 (s, 3H, CH3), 2.30±2.45 (m, 2H,
vCHCH2), 1.00±1.65 (m, 4H, CH2), 0.90 (br t, Jˆ6 Hz,
3H, CH3). IR n (cm21): 2980, 1620, 1600, 1090, 1020. MS:
m/z 301 (M11). Anal. Calcd for C13H17BrOS: C, 51.83; H,
5.69%. Found: C, 51.76; H, 5.61%.
11b and 12b.: Yellow oil. 1H NMR (CDCl3, d ppm): 7.10±
7.40 (m, 4H, C6H4), 6.30 (t, Jˆ6 Hz, 0.43H, vCH), 6.10 (s,
0.57H, vCH), 2.35 (s, 3H, CH3), 2.00±2.30 (m, 2H,
vCHCH2), 1.05±1.70 (m, 6H, CH2), 0.85 (br, t, Jˆ6 Hz,
3H, CH3). IR n (cm21): 3080, 2930, 1645, 1500, 1090, 1020.
MS: m/z 237 (M1).
General procedure for the synthesis of 13
General procedure for the synthesis of 4c±e, 11c±e and
12c±e
To a freshly prepared suspension of Cp2Zr(H)Cl (1.5 mmol)
in THF (6 ml) at rt was injected a solution of acetylenic
sulfoxides 1a (1.36 mmol) in THF (0.5 ml) under nitrogen,
the reaction mixture was stirred for about 30 min until the
precipitate completely disappeared. To the resulting clear
green solution was then added Pd(PPh3)4 (0.07 mmol) and
alkynyliodonium tosylates (1.36 mmol), the mixture was
stirred for 2 h at ambient temperature. The product was
washed with saturated aq. NH4Cl (8 ml) then extracted
into diethyl ether, dried with MgSO4, ®ltered and
concentrated in vacuo. The residue was puri®ed by prepara-
tive TLC (silica gel, hexane/AcOEtˆ10:1) to give 13.
To a freshly prepared suspension of Cp2Zr(H)Cl (1.5 mmol)
in THF (6 ml) at rt was added a solution of acetylenic sulf-
oxides 1 (1.36 mmol) in THF (0.5 ml) under nitrogen, the
reaction mixture was stirred for about 30 min until the pre-
cipitate completely disappeared. To the resulting clear green
solution was then added 1.30 mmol of I2 (or NBS), the
mixture was stirred for 1 h at ambient temperature. The
reaction mixture was then poured into 20 ml of saturated
aqueous NaHCO3 and extracted with 10% EtOAc/hexanes
(15 ml, 2£). The combined organic layers were washed with
saturated aqueous NaCl, dried over Na2SO4, and ®ltered
through a pad of Celite atop silica gel. Solvent was removed
by rotary evaporator under reduced pressure to give a crude
oil, which was puri®ed by preparative TLC (silica gel,
hexane/AcOEtˆ10:1) to give 4c±e, 11c±e and 12c±e.
1
13. Yellow oil. H NMR (CDCl3, d ppm): 7.02±7.16 (m,
10H, C6H5), 6.90 (s, 1H, vCH), 2.15±2.40 (m, 2H,
vCCH2), 1.05±1.70 (m, 4H, CH2), 0.91 (br t, Jˆ6 Hz,
3H, CH3). IR n (cm21): 3060, 3005, 2970, 2940, 2895,
2870, 2160, 1570, 1500, 1090, 1015. MS: m/z 308 (M1).

P. Zhong et al. / Tetrahedron 56 (2000) 8921±8925
8925
9. Kosugi, H.; Kitaoka, M.; Tagami, K.; Takahashi, A.; Uda, H.
J. Org. Chem. 1987, 52, 1078.
10. Posner, G. H.; Tang, P. -W. J. Org. Chem. 1978, 43, 4131.
Anal. Calcd for C20H20OS: C, 77.88; H, 6.53%. Found: C,
77.57; H, 6.59%.
Â
11. Villar, J. M.; Delgado, A.; Llebaria, A.; Moreto, J. M.; Molins,
Acknowledgements
E.; Miravitlles, C. Tetrahedron 1996, 52, 10525.
12. Zhu, L. S.; Huang, Z. Z.; Huang, X. J. Chem. Res. (S) 1996,
112; Dabdoub, M. J.; Begnini, M. L.; Guerrero Jr., P. G.
Tetrahedron 1998, 54, 2371.
Project 29772007 was supported by the National Nature
Science Foundation of China. This work was also supported
by The Nature Science Foundation of Zhejiang Province.
13. Sung, J. W.; Jang, W. B.; Oh, D. Y. Tetrahedron Lett. 1996,
37, 7537.
14. Hyla-Kryspin, I.; Gleiter, R.; KruÈger, C.; Zwettler, R.; Erker,
G. Organometallics 1990, 9, 517.
References
15. Lipshutz, B. H.; Keil, R.; Barton, J. C. Tetrahedron Lett. 1992,
33, 5861; Huang, X.; Zhong, P. J. Chem. Soc., Perkin Trans. 1
1999, 1543.
1. De Lucchi, O.; Pasquato, L. Tetrahedron 1988, 44, 6755.
2. Tsuchihashi, G.; Mitamura, S.; Ogura, K. Tetrahedron Lett.
1976, 855.
3. Posner, G. H.; Asirvatham, E.; Ali, S. F. J. Chem. Soc., Chem.
Commun. 1985, 542.
16. Tucker, C. E.; Knochel, P. J. Am. Chem. Soc. 1991, 113, 9888.
17. Deloux, L.; Skrzypczak-Jankun, E.; Cheesman, B. V.;
Srebnik, M. J. Am. Chem. Soc. 1994, 116, 10302.
18. Huang, X.; Duan, D.-H. Chem. Commun. 1999, 1741.
19. Stang, P. J.; Surber, B. W.; Chen, Z. C.; Roberts, K. A.;
Anderson, A. G. J. Am. Chem. Soc. 1987, 109, 228.
20. Annunziata, R.; Cinquini, M. J. Chem. Soc., Perkin Trans. 1
1979, 1684.
4. Satch, T.; Yamakawa, K. J. Syn. Org. Chem. Jpn. 1989, 47, 734.
5. Still, I. W. J. Phosphor Sulfur Silicon 1991, 58, 129.
6. Madesclaine, M. Tetrahedron 1986, 42, 5459.
7. (a) Mikolajczyk, M.; Grzejszczak, S.; Midura, W.; Zatorski, A.
Synthesis 1976, 396. (b) Craig, D.; Daniels, K.; Marsh, A.;
Rainford, D.; Smith, A. M. Synlett 1990, 531. (c) Mikolajczyk,
M.; Perlikowska, W. O.; Melanczuk, J.; Crzstau, H. J.;
Perrauddarcy, A. Synlett 1991, 913.
21. Diederichs, S.; Delaunay, J.; Mabon, G.; Simonet, J.
Tetrahedron Lett. 1995, 36, 8423.
8. Cardellicchio, C.; Fiandanese, V.; Naso, F. J. Org. Chem. 1992,
57, 1718.