Highly stereoselective method to prepare bis-phenylchalcogen alkenes via addition of chalcogenolate to phenylseleno alkynes

Article abstract of DOI:10.1016/j.tetlet.2012.02.028

The preparation of bis-phenylchalcogen alkenes starting from phenylseleno alkynes is described. The nucleophilic species of selenium, tellurium and sulfur were generated in situ from the reaction of the respective diphenyl dichalcogenide with NaBH₄ in PEG-400 as solvent. The chalcogenolate anions were efficiently and selectively added to a variety of phenylselenoalkynes at mild conditions, furnishing the respective (Z)-1,2-bis-phenylchalcogen alkenes in good yields.

Full text of DOI:10.1016/j.tetlet.2012.02.028

Tetrahedron Letters 53 (2012) 2066–2069
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Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Highly stereoselective method to prepare bis-phenylchalcogen alkenes
via addition of chalcogenolate to phenylseleno alkynes
⇑
Gelson Perin , Elton L. Borges, Diego Alves
LASOL, CCQFA, Universidade Federal de Pelotas, UFPel, PO Box 354, 96010-900 Pelotas, RS, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history:
The preparation of bis-phenylchalcogen alkenes starting from phenylseleno alkynes is described. The
nucleophilic species of selenium, tellurium and sulfur were generated in situ from the reaction of the
respective diphenyl dichalcogenide with NaBH4 in PEG-400 as solvent. The chalcogenolate anions were
efficiently and selectively added to a variety of phenylselenoalkynes at mild conditions, furnishing the
respective (Z)-1,2-bis-phenylchalcogen alkenes in good yields.
Received 4 January 2012
Revised 30 January 2012
Accepted 6 February 2012
Available online 18 February 2012
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
PEG-400
Vinyl chalcogenides
Bis-chalcogenides
Between the methods for the selective preparation of isolated or
conjugated olefins with control in the stereochemistry of the double
bond, the transmetallation of vinyl chalcogenides is a very efficient
protocol.1 The increasing interest in the use of vinyl chalcogenides
(tellurides and selenides) as a key intermediate in organic synthesis
is due, in part, to the plethora of selective methods for their prepa-
ration, their high stability and versatility.1,2 Among the vinyl
chalcogenides, 1,2-bis-organochalcogen alkenes are particularly
interesting synthons, because they can be used as precursor to
enediynes and other functionalized olefins with total control in
the stereochemistry.3 1,2-Bis-organylchalcogen alkenes have been
prepared by the Y–Y (S–S, Se–Se, Te–Te) bond addition to alkynes
catalyzed by transition metal complexes [Pd(PPh3)4, P(OiPr)3/[Pd],
Pt(PR3)4],4 CsF or Cs2CO3,5 CsOH,6 Ti(O-iC3H7)4/iC3H7MgCl,7 base8
or under photochemical9 and thermal10 conditions. These protocols
afford selectively (Z)-1,2-bis-organylchalcogen alkenes or, in some
cases, a mixture of Z/E isomers. (E)-1,2-bis-arylseleno- and (E)-
1,2-bis-aryltelluro styrenes were selectively prepared starting from
phenylacetylene and diaryl dichalcogenides under solvent-free11 or
in ionic liquid12 using NaBH4 to generate the nucleophilic chalcog-
enium species. The thio-analogues (E)-1,2-bis-arylthio alkenes
were prepared using GaCl313 or under electrochemical conditions.14
However, the number of methodologies for accessing selec-
tively mixed 1,2-bis-organylchalcogen alkenes (S–Se, S–Te, Se–
Te), is limited. Few important exceptions are the studies performed
by Dabdoub et al. which used the hydrozirconation of butylseleno-
acetylene followed by trapping the b-zirconated vinylselenide
intermediate with C4H9TeBr.15 The reaction afforded exclusively
the (E)-1-butyltelluro-2-butylselenoethene. When substituted al-
kynes were used, a mixture of vic- and gem-bis-organylchalcogen
alkenes was obtained. More recently, the same group described
the hydrochalcogenation of alkynyl sulfides using lithium butylse-
lenolate and butyltellurolate to prepare selectively (Z)-1-butylch-
alcogeno-2-phenylthio-1-organylalkenes in good yields.16 The
lithium chalcogenolate anions were generated in situ by the inser-
tion of elemental Se or Te in nBuLi.
Alternatively, the nucleophilic chalcogenium species can be
generated in situ by the cleavage of the Y–Y bond in dichalcoge-
nides with sodium borohydride in ethanol. The preparation of
nucleophilic organoselenium by this method was firstly described
by Sharpless and Lauer17 in 1973 and was later extended to other
chalcogenium compounds (S–S and Te–Te). Miyashita et al. have
shown that the real structure of the nucleophilic selenium species
generated in ethanol is not a naked selenolate anion, but the so-
dium phenylseleno(triethoxy)borate complex,
a slightly weak
nucleophile.18 By using the RYYR/NaBH4/EtOH system several
(Z)-1-organylseleno- and (Z)-1-organyltelluro-2-phenylthio orga-
nyl alkenes were selectively prepared by the hydroselenation and
hydrotelluration of phenylthioalkynes.19 However, to our knowl-
edge, the hydrochalcogenation of selenoalkynes to afford mixed
(Z)-bis-phenylchalcogen alkenes with the organylselenium moiety
at the terminal sp2-C was not yet described. In this sense, we report
R
PEG-400, NaBH4
(C6H5Y)2
+
SeC6H5
R
60 oC, N2
C6H5Y
SeC6H5
1a-d
2a-c
3a-j
⇑
Corresponding author.
E-mail addresses: gelson_perin@ufpel.edu.br, perin@pq.cnpq.br (G. Perin).
Scheme 1. General scheme of the reaction.
0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2012.02.028

G. Perin et al. / Tetrahedron Letters 53 (2012) 2066–2069
2067
Table 1
Initially, we chose 1-phenylseleno-2-phenylethyne 1a
(1.0 mmol) and diphenyl diselenide (0.5 mmol) as the standard
starting materials to establish the best reaction conditions under
N2 atmosphere (Table 1). We examined temperature, amount of di-
phenyl diselenide, reducing agent, and the nature of the solvent.
When the nucleophilic selenium species was generated using EtOH
as solvent under reflux, unsatisfactory yield of product 3a was ob-
tained and a great amount of diphenyl diselenide and starting
material 1a was recovered (Table 1, entry 1). On the other hand,
better results were obtained using PEG-400 as solvent (Table 1, en-
tries 2–5). Thus, at room temperature, the reaction proceeded
slowly and resulted in a 55% yield after stirring for 14 h (Table 1,
entry 2). Fortunately, when the same reaction was performed by
gently heating (60 °C) for 3 h, the yield of product 3a increased
to 64% (Table 1, entry 3).
In another experiment, it was observed that using 0.6 mmol of
2a, product 3a was obtained in an 81% yield (Table 1, entry 4).
An increase in temperature caused a decrease in the yield of com-
pound 3a (Table 1, entry 5). Glycerol, another hydroxylated sol-
vent, was also used, but low yields of product 3a were observed
in all the tested conditions. The best result with glycerol was ob-
tained in a reaction at 90 °C, giving 3a in a 43% yield (Table 1, entry
Optimization of the synthesis of 3aa
C6H5
solvent, NaBH4
temperature, N2
(C6H5Se)2
+
C6H5
SeC6H5
C6H5Se
SeC6H5
1a
2a
3a
Entry
2a (mmol)
Temp (°C)
Solvent
Time (h)
Yieldb (%)
1
2
3
4
5
6
7
0.5
0.5
0.5
0.6
0.6
0.6
0.6
78
25
60
60
90
90
60
Ethanol
24
14
3
3
3
22
55
64
81
45
43
31c
PEG-400
PEG-400
PEG-400
PEG-400
Glycerol
PEG-400
3
3
a
Reactions performed in the presence of 1a (1.0 mmol), 2a, NaBH4 (0.7 mmol),
and solvent (3.0 mL) under N2 atmosphere.
b
Yields after purification by column chromatography.
1.2 mmol of NaBH4 was used.
c
herein the results of the hydrochalcogenation of phenylseleno al-
kynes using nucleophilic species of chalcogenium anions generated
in PEG-400 (Scheme 1).20
Table 2
Hydrochalcogenation of phenylseleno alkynes using PEG-400 as solvent
Entry
1
Phenylseleno alkyne 1
(C6H5Y)2
2
Product 3
Time (h)
3
Ratio (Z):(E)a
Yieldb (%)
81
C6H5
C6H5
C6H5
C4H9
C4H9
C4H9
HO
SeC6H5
SeC6H5
SeC6H5
SeC6H5
SeC6H5
SeC6H5
C6H5
1a
1a
1a
1b
1b
1b
(C6H5Se)2 2a
(C6H5S)2 2b
(C6H5Te)2 2c
(C6H5Se)2 2a
(C6H5S)2 2b
(C6H5Te)2 2c
97:3
C6H5Se
SeC6H5
SeC6H5
SeC6H5
SeC6H5
SeC6H5
SeC6H5
3a
C6H5
2
3
4
5
6
3
4
3
3
4
98:2
74
30c
76
76
55
C6H5S
3b
C6H5
81:19
>99:1
98:2
C6H5Te
3c
3d
C4H9
C6H5Se
C4H9
C6H5S
3e
C4H9
97:3
C6H5Te
3f
OH
SeC6H5
SeC6H5
SeC6H5
7
8
(C6H5Se)2 2a
(C6H5S)2 2b
3
3
100:0
100:0
78
83
1c
1c
1c
C6H5Se
OH
SeC6H5
3g
HO
HO
H
C6H5S
SeC6H5
3h
OH
9
(C6H5Te)2 2c
(C6H5Se)2 2a
3
2
100:0
>99:1
70
C6H5Te
C6H5Se
SeC6H5
SeC6H5
3i
SeC6H5
10
20d
1d
3j
a
b
c
Determined by GC/MS of the crude reaction mixture and confirmed after isolation of pure products.
Yields after purification by column chromatography.
The formation of a small amount of 3a was observed.
d
The main product on this reaction was tris-(phenylseleno)-ethene (62% yield).

2068
G. Perin et al. / Tetrahedron Letters 53 (2012) 2066–2069
6). When the reaction was performed using a higher amount of
NaBH4 (1.2 mmol) 3a was obtained only in 31% yield (Table 1, en-
try 7). In an optimized reaction, NaBH4 was added in a mixture of
diphenyl diselenide 1a and PEG-400. The heterogeneous reaction
mixture was stirred for 30 min at room temperature under N2
atmosphere. After this time, 1-phenylseleno-2-phenylethyne 1a
was added and the mixture was heated at 60 °C for 3 h, affording
1,2-bis-phenylseleno styrene 3a in an 81% yield and a (Z):(E) ratio
of 97:3. These findings induced us to suspect that a phenylselenob-
orate complex containing PEG instead of ethanol, with a reactivity
pattern distinct compared to that using ethanol. Besides, the phe-
nylselenium moiety at alkyne acts as an activating group for the
nucleophilic addition of selenium species, with selectivity similar
to that observed to thioacetylenes.19
Since the best condition was established, the protocol was ex-
tended to other phenylselenoalkynes and diphenyl diselenide
(Scheme 1, Table 2). As can be seen in Table 2, the method was
successfully extended to other substituted selenoalkynes. Thus,
1-phenylseleno-hexyne 1b reacted under our conditions with
the phenylselenolate anion to afford 1,2-bis(phenylseleno)hex-1-
ene 3d, in a 76% yield and a (Z):(E) ratio of >99:1 (Table 2, entry
4). Similarly, (phenylseleno)prop-2-yn-1-ol 1c gave (Z)-1,2-bis-
(phenylseleno)prop-2-en-1-ol 3g as the only product in a 78%
yield after 3 h (Table 2, entry 7). Differently to that observed when
other nucleophilic selenium species were employed,8b it was ob-
served, under our conditions, the formation exclusively of 1,2-bis-
-phenylseleno alkenes from phenylseleno alkynes containing
aromatic, aliphatic and derived from propargylic alcohol. The
exception was the terminal phenylselenoacetylene 1d, which
gives the tri-substituted phenylseleno ethene as the main product
(62% yield), with a modest amount of the expected (Z)-1,2-bis-
(phenylseleno)ethene 3j. We believe that this lack of selectivity
to the di-substituted vinyl selenide is due to the high reactivity
of the terminal, triple bond in 1d in view of steric and electronic
factors.
References and notes
1. (a) Zeni, G.; Lüdtke, D. S.; Panatieri, R. B.; Braga, A. L. Chem. Rev. 2006, 106,
1032; (b) Comasseto, J. V.; Barrientos-Astigarraga, R. E. Aldrichim. Acta 2000, 33,
66; (c) Comasseto, J. V.; Ling, L. W.; Petragnani, N.; Stefani, H. A. Synthesis 1997,
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2. (a) Beletskaya, I. P.; Ananikov, V. P. Chem. Rev. 2011, 111, 1596; (b) Perin, G.;
Lenardão, E. J.; Jacob, R. G.; Panatieri, R. B. Chem. Rev. 2009, 109, 1277; (c)
Kondo, T.; Mitsudo, T. Chem. Rev. 2000, 100, 3205.
3. (a) Zeni, G.; Braga, A. L.; Stefani, H. A. Acc. Chem. Res. 2003, 36, 731; (b) Alves, D.;
Schumacher, R. F.; Brandão, R.; Nogueira, C. W.; Zeni, G. Synlett 2006, 1035; (c)
Zeni, G.; Perin, G.; Cella, R.; Jacob, R. G.; Braga, A. L.; Silveira, C. C.; Stefani, H. A.
Synlett 2002, 975; (d) Zeni, G.; Nogueira, C. W.; Pena, J. M.; Pilissão, C.;
Menezes, P. H.; Braga, A. L.; Rocha, J. B. T. Synlett 2003, 579; (e) Zeni, G.; Alves,
D.; Pena, J. M.; Braga, A. L.; Stefani, H. A.; Nogueira, C. W. Org. Biom. Chem. 2004,
2, 803; (f) Alves, D.; Zeni, G.; Nogueira, C. W. Tetrahedron Lett. 2005, 46, 8761.
4. (a) Ananikov, V. P.; Kabeshov, M. A.; Beletskaya, I. P.; Khrustalev, V. N.; Antipin,
M. Y. Organometallics 2005, 24, 1275; (b) Ananikov, V. P.; Beletskaya, I. P.;
Aleksandrov, G. G.; Eremenko, I. L. Organometallics 2003, 22, 1414.
5. Nishiyama, Y.; Ohnishi, H.; Koguma, Y. Bull. Chem. Soc. Jpn. 2009, 82, 1170.
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7. Silveira, C. C.; Cella, R.; Vieira, A. S. J. Organomet. Chem. 2006, 691, 5861.
8. (a) Lara, R. G.; Borges, E. L.; Lenardão, E. J.; Alves, D.; Jacob, R. G.; Perin, G. J. Braz.
Chem. Soc. 2010, 21, 2125; (b) Moro, A. V.; Nogueira, C. W.; Barbosa, N. B. V.;
Menezes, P. H.; Rocha, J. B. T.; Zeni, G. J. Org. Chem. 2005, 70, 5257.
9. (a) Ogawa, A.; Tsuboi, Y.; Obayashi, R.; Yokoyama, K.; Ryu, I.; Sonoda, N. J. Org.
Chem. 1994, 59, 1600; (b) Ogawa, A.; Yokoyama, K.; Obayashi, R.; Han, L.-B.;
Kambe, N.; Sonoda, N. Tetrahedron 1993, 49, 1177; (c) Back, T. G.; Krishna, M. V.
J. Org. Chem. 1988, 53, 2533; (d) Ogawa, A.; Yokoyama, H.; Yokoyama;
Masawaki, T.; Kambe, N.; Sonoda, N. J. Org. Chem. 1991, 56, 5721; (e) Ogawa, A.;
Ogawa, I.; Sonoda, N. J. Org. Chem. 2000, 65, 7682; (f) Ogawa, A.; Obayashi, R.;
Ine, H.; Tsuboi, Y.; Sonoda, N.; Hirao, T. J. Org. Chem. 1998, 63, 881.
10. (a) Potapov, V. A.; Amosova, S. V.; Beletskaya, I. P.; Starkova, A. A.; Hevesi, L.
Phosphorus, Sulfur, Silicon 1998, 136, 591; (b) Kuniyasu, H.; Ogawa, A.;
Miyazaki, S.; Ryu, I.; Kambe, N.; Sonoda, N. J. Am. Chem. Soc. 1991, 113, 9796;
(c) Potapov, V. A.; Amosova, S. V.; Doron’kina, I. V.; Starkova, A. A.; Hevesi, L.
Sulfur Lett. 2002, 25, 101.
11. Perin, G.; Jacob, R. G.; Dutra, L. G.; Azambuja, F.; Santos, G. F. F.; Lenardão, E. J.
Tetrahedron Lett. 2006, 47, 935.
12. (a) Lenardão, E. J.; Dutra, L. G.; Saraiva, M. T.; Jacob, R. G.; Perin, G. Tetrahedron
Lett. 2007, 48, 8011; (b) Lenardão, E. J.; Gonçalves, L. C. C.; Mendes, S. R.;
Saraiva, M. T.; Alves, D.; Jacob, R. G.; Perin, G. J. Braz. Chem. Soc. 2010, 21, 2093.
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2823.
Following, we studied the reaction of diphenyl disulfide with
phenylseleno alkynes and it was observed that the method is very
selective to the preparation of mixed 1,2-bis-phenylchalcogene al-
kenes with Z-configuration (Table 2, entries 2, 5 and 8). Similarly to
that observed with selenium, the reaction proceeded cleanly under
mild reaction conditions, and the addition of the phenylthiolate to
the triple bond occurred stereoselectively, giving almost exclu-
sively the corresponding Z isomers for aromatic and aliphatic
phenylselenoalkyne (Table 2, entries 2 and 5). When the propargy-
lic alcohol derivative 1c was the starting acetylene, only the
respective (Z)-allyl alcohol 3h was obtained in an 83% yield (Table
2, entry 8).
It was also possible to obtain the tellurium analogues using the
same reaction conditions. Despite the lower yields and selectivity
compared to the Se- and S-analogues, these are very interesting re-
sults, once it is possible to prepare mixed (Z)-1-phenylseleno-2-
phenylteluro-1-organyl alkenes by a very simple hydrotelluration
protocol.
15. Dabdoub, M. J.; Begnini, M. L.; Guerrero, P. G., Jr. Tetrahedron 1998, 54, 2371.
16. Dabdoub, M. J.; Dabdoub, V. B.; Perreira, M. A.; Baroni, A. C. M.; Marques, F. A.;
Oliveira, P. R.; Guerrero, P. G., Jr. Tetrahedron Lett. 2010, 51, 5141.
17. Sharpless, K. B.; Lauer, R. F. J. Am. Chem. Soc. 1973, 95, 2697.
18. Miyashita, M.; Suzuki, T.; Hoshino, M.; Yoshikoshi, A. Tetrahedron 1997, 53,
12469.
19. Dabdoub, M. J.; Dabdoub, V. B.; Perreira, M. A. Tetrahedron Lett. 2001, 42, 1595.
20. General procedure for the synthesis of bis-chalcogen alkenes 3: To
a
mixture of dichalcogenide 2 [0.6 mmol of (C6H5Se)2 or 0.8 mmol to (C6H5Te)2
and (C6H5S)2] in PEG-400 (3 mL) under N2 atmosphere, NaBH4 (0.027 g,
0.7 mmol) was added at room temperature and stirred for 30 min. Then, the
appropriate phenylselenoalkyne 1 (1.0 mmol) was added and the temperature
was slowly raised to 60 °C and the reaction progress was followed by TLC. After
the time indicated in Table 2, the reaction mixture was washed with a mixture
of hexane/ethyl acetate 95:5 (3 Â 3 mL) and the upper organic phases were
separated from PEG, dried with MgSO4 and the solvent was evaporated under
reduced pressure. The product was isolated by column chromatography using
hexane or hexane/ethyl acetate as eluent. All the compounds were
characterized by the comparison of their 1H NMR spectra with those in the
literature. Selected spectral data for: (Z)-1,2-bis-phenylseleno styrene 3a:21
Yellow oil; 1H NMR (200 MHz, CDCl3) d (ppm) 7.58–7.64 (m, 2H); 7.59 (s, 1H)
7.46–7.51 (m, 2H); 7.09–7.40 (m, 11H). MS m/z (rel. int., %) Z isomer: 416 (M+,
15.9), 259 (44.1), 178 (100.0), 77 (54.1); E isomer: 416 (M+, 4.4), 259 (28.6), 178
(100.0), 77 (53.5). (Z)-2-phenylseleno-1-phenylthio styrene 3b:8a Yellow oil;
1H NMR (400 MHz, CDCl3) d (ppm) 7.62–7.64 (m, 2H); 7.52–7.55 (m, 2H); 7.51
(s, 1H); 7.06–7.34 (m, 11H). MS m/z (rel. int., %) Z isomer: 368 (M+, 18.7), 259
(23.8), 179 (100.0), 77 (32.5); E isomer: 368 (M+, 5.4), 259 (13.5), 179 (100.0),
77 (72.9). (Z)-2-phenylseleno-1-phenyltelluro styrene 3c:22 Dark yellow oil;
1H NMR (400 MHz, CDCl3) d (ppm) 7.56–7.65 (m, 3H); 7.49–7.52 (m, 2H); 7.31–
7.40 (m, 5H); 7.09–7.3 (m, 6H). MS m/z (rel. int., %) Z isomer: 466 (M+, 9.3), 259
(18.8), 178 (60.2), 77 (100.0); E isomer: 466 (M+, 8.13), 259 (20.0), 178 (79.3),
77 (100.0). (Z)-1,2-bis-(phenylseleno)hex-1-ene 3d:23 Yellow oil; 1H NMR
(400 MHz, CDCl3) d (ppm) 7.51–7.56 (m, 4H); 7.25–7.31 (m, 6H); 6.93 (s, 1H);
2.28 (t, J = 7.2 Hz, 2H); 1.47 (qui, J= 7.2 Hz, 2H); 1.23 (sex, J = 7.2 Hz, 2H); 0.82
(t, J = 7.2 Hz, 3H). MS m/z (rel. int., %) Z isomer: 396 (M+, 29.5), 239 (14.8), 183
(51.0), 157 (50.2), 81 (100.0); E isomer: 396 (M+, 20.3), 239 (18.5), 183 (60.10),
157 (46.6), 81 (100.0). (Z)-1-phenylseleno-2-phenylthiohex-1-ene 3e: Yellow
oil; 1H NMR (400 MHz, CDCl3) d (ppm) 7.54–7.57 (m, 2H); 7.35–7.38 (m, 2H);
7.26–7.30 (m, 5H); 7.18–7.22 (m, 1H); 6.81 (s, 1H); 2.23 (t, J = 7.2 Hz, 2H); 1.48
In conclusion, we presented here a new methodology for the
addition of nucleophilic chalcogenium species generated in PEG-
400 to phenylseleno alkynes. This new reaction media permitted
the selective preparation of 1,2-bis-organoseleno alkenes, as well
as, of mixed (S, Te) 1,2-bis-organochalcogen alkenes. The selectiv-
ity is extensive to aromatic, alkyl and propargyl selenoalkynes.
Acknowledgments
The authors are grateful to FAPERGS (PRONEX 10/0005-1, PRO-
NEM 11/2026-4 and PqG 11/0719-3), CAPES, FINEP and CNPq for
the financial support.

G. Perin et al. / Tetrahedron Letters 53 (2012) 2066–2069
2069
(qui, J = 7.2 Hz, 2H); 1.24 (sex, J = 7.2 Hz, 2H); 0.83 (t, J = 7.2 Hz, 3H); 13C NMR
(100 MHz, CDCl3) d 135.9, 133.8, 132.7, 131.1, 130.2, 129.2, 128.9, 128.4, 127.4,
126.6, 37.5, 30.6, 21.9, 13.7. MS m/z (rel. int., %) Z isomer: 348 (M+, 79.5), 239
(25.1), 157 (40.4), 135 (100.0), 77 (94.9); E isomer: 348 (M+, 6.0), 167 (100.0),
147 (89.3), 135 (68.9), 77 (27.0); HRMS (ESI): m/z calcd for C18H20SSe [M+H]+:
349.0529; found: 349.0525. (Z)-1-phenylseleno-2-phenyltellurohex-1-ene
3f: Dark yellow oil; 1H NMR (400 MHz, CDCl3) d (ppm) 7.82–7.84 (m, 2H);
7.50–7.52 (m, 2H); 7.21–7.34 (m, 6H); 7.08 (s, 1H); 2.28 (t, J = 7.2 Hz, 2H); 1.42
(qui, J = 7.2 Hz, 2H); 1.17 (sex, J = 7.2 Hz, 2H); 0.77 (t, J = 7.2 Hz, 3H). 13C NMR
(100 MHz, CDCl3) d 139.6, 132.8, 131.8, 131.5, 129.3, 129.2, 128.1, 127.1, 127.0,
114.1, 42.2, 32.0, 21.7, 13.7. MS m/z (rel. int., %) Z isomer: 446 (M+, 11.9), 234
(47.5), 157 (14.8), 77 (100.0) E isomer: 446 (M+, 11.0), 234 (38.8), 157 (17.7),
77 (100.0); HRMS (ESI): m/z calcd for C18H20SeTe [M+H]+: 446.9871; found:
446.9843. (Z)-1,2-bis-(phenylseleno)prop-2-en-1-ol 3g:23 Yellow oil; 1H NMR
(200 MHz, CDCl3) d (ppm) 7.50–7.61 (m, 4H); 7.38 (s, 1H); 7.24–7.34 (m, 6H);
4.13 (s, 2H); 1.99 (s, 1H). MS m/z (rel. int., %) 370 (M+, 20.7), 212 (25.5), 183
(60.8), 157 (50.0), 77 (100.0). (Z)-3-(phenylseleno)-2-(phenylthio)prop-2-en-
1-ol 3h:24 Yellow oil; 1H NMR (200 MHz, CDCl3) d (ppm) 7.56–7.62 (m, 2H);
7.20–7.43 (m, 9H); 4.12 (s, 2H); 1.82 (s, 1H). MS m/z (rel. int., %) 322 (M+, 50.3),
212 (44.1), 183 (87.0), 135 (96.2), 77 (100.0). (Z)-3-(phenylseleno)-2-
(phenyltelluro)prop-2-en-1-ol 3i: Dark yellow oil; 1H NMR (400 MHz,
CDCl3) d (ppm) 7.81–7.83 (m, 2H); 7.53–7.57 (m, 3H); 7.22–7.34 (m, 6H);
4.15 (s, 2H); 1.80 (s, 1H). 13C NMR (100 MHz, CDCl3) d 138.7, 134.3, 132.8,
130.7, 129.5, 129.4, 128.3, 127.7, 125.1, 70.6. MS m/z (rel. int., %) 420 (M+, 6.2),
234 (21.7), 157 (14.9), 77 (100.0); HRMS (ESI): m/z calcd for C15H14OSeTe
[M+Na]+: 442.9170; found: 442.9178. (Z)-1,2-bis-(phenylseleno)ethylene
3j:25 Yellow oil. 1H NMR (200 MHz, CDCl3) d (ppm) 7.42–7.53 (m, 4H); 7.24–
7.32 (m, 6H); 7.17 (s, 2H). MS m/z (rel. int., %) Z isomer: 340 (M+, 22.1), 183
(94.4), 157 (65.2), 77 (100.0); E isomer: 340 (M+, 14.5), 183 (82.7), 157 (61.2),
77 (100.0).
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