Cerium(III)-mediated efficient and steroselective hydrochalcogenation of terminal alkynes

Article abstract of DOI:10.1055/s-0029-1217029

Vinylic chalcogenides were synthesized stereospecifically by hydrochalcogenation of propargylic amines or alcohols mediated by cerium(III) chloride. The products were obtained in good yields and with high regio- and stereoselectivities. Georg Thieme Verla

Full text of DOI:10.1055/s-0029-1217029

PAPER
4015
Cerium(III)-Mediated Efficient and Stereoselective Hydrochalcogenation of
Terminal Alkynes
Cerium(III)-Medl
a
ydrochalco
u
genation of
A
d
lkynes io C. Silveira,* Samuel R. Mendes, Daniel D. Rosa, Gilson Zeni
Departamento de Química, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS, Brazil
Fax +55(55)32208754; E-mail: silveira@quimica.ufsm.br
Received 15 May 2009; revised 27 July 2009
nickel(II)-catalyzed cross-coupling reactions with
Abstract: Vinylic chalcogenides were synthesized stereospecifi-
cally by hydrochalcogenation of propargylic amines or alcohols
mediated by cerium(III) chloride. The products were obtained in
good yields and with high regio- and stereoselectivities.
alkynes20a or metal acetylides20b are useful transforma-
tions. Transmetalation reactions are particularly impor-
tant in the chemistry of vinylic tellurides; treatment of
these compounds with lithium21, lithium/cerium,21a lithi-
um/zinc,22 zinc,23 sodium,24 calcium,25 or Grignard re-
agents,26 followed by the capture of the vinyl metals with
electrophiles, occurs with retention of the geometry of the
carbon–carbon bond. In addition, vinylcuprates can be
prepared by transmetalation of vinyl tellurides.27–29 The
direct substitution of tellurium moieties by alkyl or alky-
nyl groups has also been described.21d,30–32 The vinyl orga-
nometallic compounds obtained in this way can react with
carbonyl compounds,33 a,b-unsaturated systems,34 or ep-
oxides.28
Key words: cerium chloride, vinylic chalcogenides, hydrochalco-
genation, selenium, tellurium
Cerium chloride has recently emerged as a very useful,
cheap, nontoxic, and water-tolerant Lewis acid catalyst
that imparts high regio- and chemoselectivity in various
chemical transformations. It can be used in several forms,
such as the heptahydrate,1 the anhydrous form,2 or in com-
bination with sodium iodide.3 These forms can also be
used on solid supports that modify the reactivity of the ce-
rium salt.4 Organocerium compounds are also extensively
used in organic synthesis.5
To the best of our knowledge, however, there is no proto-
col that describes the preparation of vinylic chalcogenides
promoted by cerium chloride. In the light of the above
comments, it was of interest to design a simple, efficient,
and versatile method for the stereoselective synthesis of
vinylic chalcogenides, with the aim of using them in the
construction of olefins with defined stereochemistry,
thereby giving ready access to vinylic metal species.
The recent and remarkable developments in the use of or-
ganochalcogenide compounds as synthetic reagents and
intermediates are the subject of many review articles6 and
books.7 Among the organochalcogenide compounds, vi-
nylic chalcogenides play an important role in organic syn-
thesis because of their unusual reactivity.8
We describe preparations of functionalized vinylic se-
lenides and tellurides by cerium chloride catalyzed hydro-
chalcogenation of propargylic alcohols and amines. The
first reactions were performed by using diphenyl dise-
lenide (1 mmol) and sodium borohydride (2 equiv) as a re-
ducing agent in methanol as the solvent. Propargylic
alcohol (1 mmol) and cerium(III) chloride heptahydrate (1
mmol) were added, and the mixture was refluxed for 4
hours. The corresponding vinylic selenide was obtained in
low yield (~10%) and with low regioselectivity. Increas-
ing the amount of sodium borohydride to four equivalents
did not improve the results. Next, we cleaved diphenyl
diselenide with sodium borohydride in a separate flask
and transferred this mixture to a solution of the alkyne and
cerium trichloride heptahydrate in methanol at 0 °C. Fi-
nally, the mixture was then heated at the reflux tempera-
ture. The corresponding vinylic selenide was isolated in
very high yield (96%), but again with low regioselectivity,
the selenides 2a and 3a being isolated in a 45:55 ratio
(Scheme 1).
The transition metal-catalyzed addition of organochalco-
genide compounds to alkynes has recently attracted a con-
siderable amount of interest, and palladium-9 and nickel-
catalyzed10 thiolation and selenation reactions of alkynes
have been described. Most of these methods give the de-
sired compounds as mixtures of regio- and stereoisomers.
Noncatalytic addition reactions have also been described,
but these also show low regioselectivity.11 The use of ex-
pensive indium reagents has been recently described for
the hydrochalcogenation of aminoalkynes12 or alkynols13
to give the corresponding Markovnikov products. Mix-
tures of Markovnikov and anti-Markovnikov products
have also been obtained by hydroselanylation of alkynes
by using sodium borohydride and ionic liquids.14
Many applications of vinylic chalcogenides have recently
been described. Among a number of useful applications of
vinyl selenides and vinyl sulfides are nickel-15,16 or palla-
dium-catalyzed17cross-coupling reactions with Grignard
reagents. In the case of vinylic tellurides, palladium-cata-
lyzed homocoupling18 and cross-coupling reactions,19 and
With the aim of improving the regioselectivity of the re-
action, we changed the solvent from methanol to isopro-
panol. The reaction once more occurred in high yield, but
with a higher preference for isomer 3a (2a/3a 37:63). In a
SYNTHESIS 2009, No. 23, pp 4015–4021
x
x.
x
x
.
2
0
0
9
Advanced online publication: 12.10.2009
DOI: 10.1055/s-0029-1217029; Art ID: M02509SS
© Georg Thieme Verlag Stuttgart · New York

4016
C. C. Silveira et al.
PAPER
ratio of the products occurred, as the geminal isomer 2a
became the main product in this case. On the basis of this
result, we decided to reevaluate the use of isopropanol as
a solvent, since this change in regioselectivity could have
been a result of using anhydrous cerium chloride. As can
be seen in Table 1, the high selectivity was indeed a result
of using a combination of anhydrous cerium chloride and
isopropanol, because, under the same conditions, metha-
nol or sec-butanol gave mixtures of products (Table 1, en-
tries 2 and 3). We then investigated the effects of
temperature on the reaction. Changing the initial temper-
ature to 0 °C or –20 °C had a dramatic effect on the selec-
tivity (Table 1, entries 5–7).
SePh
(PhSe)2, NaBH4
PhSe
OH
solvent, cerium(III)
OH
OH
0 °C
reflux
1a
2a
3a
Scheme 1
Table 1 Effects of the Solvent and the Temperature on the Selectiv-
ity of the Reaction
Entry
Solventa
i-PrOH
MeOH
s-BuOH
i-PrOH
i-PrOH
i-PrOH
i-PrOH
Temp (°C)b
Ratio 2a/3ac
>98:2
40:60
1
2
3
4
5
6
7
0
0
After evaluating the effects of the solvent, the tempera-
ture, and the form of the cerium salt, we turned our atten-
tion to the effect of the amount of cerium(III) chloride on
the reaction. The results, presented in Table 2, show that
for propargyl alcohol 1a, very high selectivity can only be
achieved by the use of a stoichiometric amount of anhy-
drous cerium(III) chloride, because smaller amounts re-
duced the regioselectivity (Table 2, entries 2–5). Note the
result shown in entry 6, which shows that a mixture of the
three possible isomers was formed in the absence of ceri-
um(III) chloride (Table 2, entry 6). We also observed that
the use of equivalent amounts of diphenyl dichalco-
genides (i.e., 0.5 equiv) and alkyne reduced the yield from
nearly quantitative to 83%. Because diphenyl diselenide
as a reagent is readily recovered by column chromatogra-
phy at the end of reaction, we used this reagent in excess
during our subsequent studies.
0
70:30
-20
r.t.
>98:2
96:4
40
90:10
reflux
87:13
a Reaction performed with 1a (1 mmol), (PhSe)2 (1 mmol), NaBH4 (3
mmol), and dry CeCl3 (1 mmol).2c,
b Initial temperature of the reaction mixture.
c Ratio determined by 1H NMR.
search for better regioselectivity, we replaced cerium(III)
chloride heptahydrate with the anhydrous salt. In this
case, a very high regioselectivity was observed (2a/3a
>98:2; Table 1, entry 1). However, a drastic change in the
Table 2 Synthesis of Vinylic Chalcogenides by Hydrochalcogenation Catalyzed by Anhydrous Cerium(III) Chloride
Entry
1
Alkyne
CeCl3 (equiv)
1.0c
Product
Time (h)
3.0
Yield (%)a
Ratio 2/3b
SePh
95
37:63
OH
PhSe
OH
2a
3a
OH
1a
1a
2
3
4
5
6
1.0
0.5
0.1
0.05
–
2a + 3a
3.0
3.0
3.0
3.0
3.0
98
97
97
98
95
>98:2
1a
1a
1a
1a
2a + 3a
2a + 3a
2a + 3a
48:52
25:75
20:80
2a + 3a + E
50:20:30d
TePh
7
8
1a
1a
1.0
3.0
3.0
95
95
>98:2
21:79
PhTe
PhSe
OH
OH
2b
3b
OH
0.05
2b + 3b
SePh
OH
2c
9
1.0
4.5
4.5
98
98
4:96
4:96
OH
3c
1b
1b
10
0.05
2c + 3c
Synthesis 2009, No. 23, 4015–4021 © Thieme Stuttgart · New York

PAPER
Cerium(III)-Mediated Hydrochalcogenation of Alkynes
4017
Table 2 Synthesis of Vinylic Chalcogenides by Hydrochalcogenation Catalyzed by Anhydrous Cerium(III) Chloride (continued)
Entry
11
Alkyne
CeCl3 (equiv)
0.05
Product
Time (h)
4.5
Yield (%)a
94
Ratio 2/3b
TePh
OH
2d
OH
1b
4:96
7:93
6:94
PhTe
3d
SePh
OH
OH
12
13
0.05
0.05
4.5
4.5
97
94
PhSe
3e
OH
2e
2f
1c
1c
TePh
OH
OH
PhTe
3f
>2:98 e
>2:98 e
SePh
3g
14
15
0.05
0.05
6.0
6.0
79
78
1d
1d
TePh
3h
SePh
OEt
16
17
18
1.0
4.5
4.5
4.5
96
96
94
3:97
3:97
7:93
OEt
PhSe
OEt
OEt
3i
1e
1e
2i
0.05
0.05
2i + 3i
TePh
OEt
1e
PhTe
O
3j
2j
N
19
0.05
4.5
92
>2:98e
N
N
PhSe
3k
O
1f
1f
20
21
0,05
0,05
0,05
O
4.5
24
90
73
69
>2:98e
>2:98e
>2:98e
PhTe
PhSe
3l
NBn2
NBn2
3m
3n
1g
1g
PhTe
22
NBn2
24
a Isolated yield.
b Determined by 1H NMR.
c CeCl3·7H2O (in all other examples, dry CeCl3 was used).2c
d 2/3/E.
e Geminal isomer 2 was undetectable by 1H NMR.
Having identified the optimal conditions, we next extend- The reaction was also extended to the other functionalized
ed the reaction to some related compounds to determine alkynes 1a–g, which showed a similar general behavior
the scope and limitations of our method. As can be seen in (Scheme 2).
Table 2, completely different behavior was observed with
R2
propargyl alcohol 1b or ether 1e, and the corresponding
(Z)-vinylic selenides were isolated with a high selectivity,
irrespective of the amount of cerium(III) chloride that was
used (1 equiv or 0.05 equiv) or of variations in the solvent
and temperature.
R1
R2
R1
R1
R2
(PhY)2, NaBH4
i-PrOH, CeCl3
XR
PhY
XR
XR
YPh
0 °C
reflux
1a–g
2a–n
3a–n
X = O, N
Y = Se, Te
Scheme 2
Synthesis 2009, No. 23, 4015–4021 © Thieme Stuttgart · New York

4018
C. C. Silveira et al.
PAPER
was stirred until colorless. A second two-necked flask equipped
with a reflux condenser was charged the alkyne (1 mmol), i-PrOH
(2 mL), and dry CeCl3 (0.012 g, 5 mol% or 0.246 g, 1 mmol; see
Table 2) under argon, and the contents of the first flask were added
at 0 °C. The mixture was then refluxed for the time indicated in
Table 2, and then cooled to r.t. H2O (15 mL) was added and the mix-
ture was extracted with EtOAc (3 × 10 mL). The organic layer was
dried (MgSO4), filtered, and concentrated under reduced pressure.
The residue was purified by column chromatography (EtOAc–hex-
anes, 5:95).
Under the conditions studied, propargyl amines could also
be used as substrates to give the corresponding vinylic se-
lenides. We also examined the corresponding reactions of
phenyl acetylene and hex-1-yne. In the case of phenyl-
acetylene, the (Z)-vinylic selenide was obtained in good
yield and high regioselectivity (Table 2, entry 14), where-
as the hex-1-yne gave the vinylic selenide as a mixture of
isomers in very low yield, even after 12 hours of heating.
The method was also applied to the corresponding telluri-
um derivatives, with very similar results to those obtained
with the selenium analogues in terms of the yield and ste-
reoselectivity of the reaction (Table 2).
2-(Phenylselanyl)prop-2-en-1-ol (2a)13a
IR (KBr): 3356, 3057, 2922, 2858, 1615, 1577, 1476, 1438, 1037,
738, 690, 473 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.54–7.49 (m, 2 H), 7.28–7.24 (m,
3 H), 5.84 (t, J = 1.47 Hz, 1 H), 5.39 (t, J = 1.10 Hz, 1 H), 4.14 (s,
2 H), 2.46 (br s, 1 H).
13C NMR (50 MHz, CDCl3): d = 141.37, 133.83, 129.24, 128.12,
127.72, 118.19, 66.25.
MS (EI): m/z (%) = 214 (49) [M+], 183 (38), 158 (31), 91 (49), 78
(100), 51 (36).
In the hydrotelluration reactions, which gave (Z)-vinylic
tellurides exclusively, the tellurolate anion and the vinylic
hydrogen are known to add to the alkyne in a trans-fash-
ion and the vinylic hydrogen comes from the hydroxyl
group of ethanol.11,13b,35 We used these results to confirm
the source of the vinylic hydrogen to our reaction. When
the reaction in was performed in tetrahydrofuran36 (an
aprotic solvent), the vinylic products 2a and 3a (>98:2)
were obtained in a yield of less than 83%. In addition,
when the reaction was repeated with propargyl ether 1e,
which lacks an acidic proton in the hydroxyl group, in tet-
rahydrofuran as the solvent, the vinylic products were not
obtained. These results, unlike those from previous
work,11,13b,35 strongly suggest that the cerium(III)-mediat-
ed addition of dichalcogenides across the triple bond fol-
lows an anti-pathway, with effective participation by the
hydroxy group from the propargyl alcohol as the source of
the vinylic hydrogen.
2-(Phenyltellanyl)prop-2-en-1-ol (2b)37
IR (KBr): 3356, 3057, 2922, 2858, 1615, 1577, 1476, 1438, 1037,
738, 690, 473 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.82–7.76 (m, 2 H), 7.33–7.20 (m,
3 H), 6.25 (t, J = 1.76 Hz, 1 H), 5.57 (t, J = 1.42 Hz, 1 H), 4.21 (s,
2 H), 2.46 (br s, 1 H).
13C NMR (50 MHz, CDCl3): d = 138.96, 129.86, 129.33, 127.94,
123.31, 112.06, 69.19.
MS (EI): m/z (%) = 264 (42) [M+], 207 (14), 117 (22), 77 (100), 57
(20), 51 (52).
(2Z)-3-(Phenylselanyl)prop-2-en-1-ol (3a)13a
IR (KBr): 3355, 3056, 2921, 2860, 1609, 1577, 1476, 1438, 1072,
736, 690, 464 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.54–7.43 (m, 2 H), 7.27–7.22 (m,
3 H), 6.61 (dt, J = 9.15 and 1.24 Hz, 1 H), 6.22 (dt, J = 9.15 and
6.05 Hz, 1 H), 4.28 (dd, J = 6.05 and 1.24 Hz, 2 H), 2.37 (br s, 1 H).
13C NMR (50 MHz, CDCl3): d = 134.54, 132.52, 131.81, 129.14,
127.07, 122.83, 61.26.
MS (EI): m/z (%) = 214 (46) [M+], 158 (89), 115 (24), 78 (100), 57
(35), 51 (37).
In conclusion, we have developed a convenient method
for the preparation of functionalized vinylic selenides and
tellurides from the corresponding alkynes by means of a
cerium chloride mediated reaction. This is the first report
describing the association between organochalcogen
group and cerium chloride, suggesting that a cerium–sele-
nium or cerium–tellurium complex may be involved in the
control of the regio- and stereoselectivity of a hydrochal-
cogenation reaction of alkynes. The products formed were
markedly dependent on the substitution pattern of the
alkyne, but very high regio- and stereoselectivities were
observed. We believe that this approach to vinylic chalco-
genides should prove quite useful in synthesis, particular-
ly as there are many ways of transforming the resulting
chalcogen functionalitiesinto a number of interesting sub-
stituted olefins with defined stereochemistries.
(2Z)-3-(Phenyltellanyl)prop-2-en-1-ol (3b)37
IR (KBr): 3359, 3051, 2920, 2853, 1610, 1582, 1472, 1434, 1035,
735, 692, 470 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.74–7.69 (m, 2 H), 7.29–7.25 (m,
3 H), 6.92 (dt, J = 9.60 and 1.40 Hz, 1 H), 6.53 (dt, J = 9.60 and 5.0
Hz, 1 H), 4.24–4.22 (m, 2 H), 2.50 (br s, 1 H).
13C NMR (50 MHz, CDCl3): d = 138.99, 137.38, 136.53, 129.13,
127.50, 107.40, 64.07.
MS (EI): m/z (%) = 264 (46) [M+], 207 (38), 117 (24), 77 (100), 57
(36), 51 (38).
Column chromatography was performed on Merck silica gel (230–
400 mesh). IR spectra were recorded on a Perkin-Elmer 1310 spec-
1
trophotometer of samples prepared as KBr pellets. H NMR (200
MHz) and 13C NMR (50 MHz) spectra were recorded on a Bruker
DPX 200 spectrometer of samples dissolved in CDCl3. Mass spec-
tra were recorded on a Hewlett Packard EM/CG HP-5988A spec-
trometer. All chemicals were of reagent grade and, if necessary,
were purified in the usual manner prior to use.
(3Z)-2-Methyl-4-(phenylselanyl)but-3-en-2-ol (3c)38
IR (KBr): 3385, 3057, 2972, 2928, 1604, 1578, 1476, 1438, 1143,
739, 691, 470 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.57–7.51 (m, 2 H), 7.28–7.24 (m,
3 H), 6.43 (d, J = 10.0 Hz, 1 H), 6.00 (d, J = 10.0 Hz, 1 H), 2.15 (br
s, 1 H), 1.41 (s, 6 H).
Vinyl Chalcogenides 2 and 3: General Procedure
NaBH4 (0.152 g, 4 mmol) was added to a soln of diphenyl dichalco-
genide (1 mmol) in i-PrOH (3 mL) under argon, and the mixture
Synthesis 2009, No. 23, 4015–4021 © Thieme Stuttgart · New York

PAPER
Cerium(III)-Mediated Hydrochalcogenation of Alkynes
4019
13C NMR (50 MHz, CDCl3): d = 136.78, 132.82, 132.63, 128.99,
127.09, 120.59, 72.77, 29.48.
MS (EI): m/z (%) = 309 (8) [M+ – 1], 207 (17), 181 (42), 165 (39),
103 (28), 91 (54), 77 (100), 51 (49).
MS (EI): m/z (%) = 242 (39) [M+], 227 (45), 158 (15), 147 (100),
128 (44), 85 (63), 77 (75), 65 (35), 51 (46).
{[(1Z)-3-Ethoxyprop-1-en-1-yl]selanyl}benzene (3i)
IR (KBr): 3057, 2974, 2866, 1608, 1578, 1477, 1438, 1102, 737,
690, 467 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.52–7.47 (m, 2 H), 7.31–7.26 (m,
3 H), 6.66 (dt, J = 9.41 and 1.22 Hz, 1 H), 6.18 (dt, J = 9.41 and
5.87 Hz, 1 H), 4.12 (dd, J = 5.87 and 1.22 Hz, 2 H), 3.54 (q,
J = 7.09 Hz, 2 H), 1.25 (t, J = 7.09 Hz, 3 H).
13C NMR (50 MHz, CDCl3): d = 137.98, 131.99, 130.94, 129.15,
127.09, 123.91, 68.77, 65.81, 15.17.
MS (EI): m/z (%) = 242 (17) [M+], 198 (35), 158 (33), 117 (26), 77
(3Z)-2-Methyl-4-(phenyltellanyl)but-3-en-2-ol (3d)38
IR (KBr): 3423, 3064, 2970, 2865, 1600, 1574, 1474, 1460, 1063,
732, 692, 458 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.81–7.75 (m, 2 H), 7.29–7.17 (m,
3 H), 6.68 (d, J = 9.85 Hz, 1 H), 6.43 (d, J = 9.85 Hz, 1 H), 2.26 (br
s, 1 H), 1.36 (s, 6 H).
13C NMR (50 MHz, CDCl3): d = 141.28, 140.37, 137.75, 129.02,
127.42, 104.45, 73.31, 29.14.
(56), 57 (100).
MS (EI): m/z (%) = 292 (46) [M+], 207 (21), 197 (42), 147 (42), 129
(41), 85 (41), 77 (100), 67 (54), 51 (52).
Anal. Calcd for C11H14OSe: C, 54.78; H, 5.85. Found: C, 54.63; H,
5.81.
(1Z)-3-Methyl-1-(phenylselanyl)pent-1-en-3-ol (3e)14
IR (KBr): 3443, 3057, 2968, 2927, 1606, 1578, 1477, 1458, 1142,
737, 691, 472 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.54–7.51 (m, 2 H), 7.29–7.25 (m,
3 H), 6.48 (d, J = 10.14 Hz, 1 H), 5.93 (d, J = 10.14 Hz, 1 H), 2.09
(br s, 1 H), 1.66 (q, J = 7.50 Hz, 2 H), 1.35 (s, 3 H), 0.96 (t, J = 7.50,
3 H).
13C NMR (50 MHz, CDCl3): d = 135.49, 132.95, 132.39, 128.97,
127.03, 121.21, 75.34, 35.00, 27.16, 8.21.
MS (EI): m/z (%) = 256 (43) [M+], 227 (100), 157 (65), 147 (88),
129 (60), 77 (82), 51 (39).
{[(1Z)-3-ethoxyprop-1-en-1-yl]tellanyl}benzene (3j)
IR (KBr): 3064, 2973, 2866, 1574, 1474, 1433, 1104, 732, 692, 633,
456 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.77–7.71 (m, 2 H), 7.29–7.20 (m,
3 H), 6.97 (dt, J = 10.00 and 1.47 Hz, 1 H), 6.51 (dt, J = 10.00 and
4.56 Hz, 1 H), 4.04 (dd, J = 4.56 and 1.47 Hz, 2 H), 3.52 (q,
J = 7.06 Hz, 2 H), 1.27 (t, J = 7.06 Hz, 3 H).
13C NMR (50 MHz, CDCl3): d = 139.83, 137.53, 133.69, 129.13,
127.51, 108.71, 70.94, 66.11, 15.28.
MS (EI): m/z (%) = 292 (17) [M+], 207 (7), 115 (18), 85 (54), 77
(41), 57 (100), 51 (16).
HRMS (ESI): m/z [M]+ calcd for C11H14OTe: 292.0107; found:
292.0121.
(1Z)-3-Methyl-1-(phenyltellanyl)pent-1-en-3-ol (3f)38
IR (KBr): 3442, 3064, 2967, 2925, 1596, 1574, 1474, 1457, 1063,
732, 692, 458 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.79–7.74 (m, 2 H), 7.27–7.20 (m,
3 H), 6.72 (d, J = 10.04 Hz, 1 H), 6.37 (d, J = 10.04 Hz, 1 H), 2.04
(br s, 1 H), 1.63 (q, J = 7.50, 2 H), 1.31 (s, 3 H), 0.95 (t, J = 7.50, 3
H).
13C NMR (50 MHz, CDCl3): d = 140.50, 139.97, 137.60, 128.90,
127.27, 105.15, 75.51, 34.70, 26.79, 7.99.
4-[(2Z)-3-(Phenylselanyl)prop-2-en-1-yl]morpholine (3k)41
IR (KBr): 3060, 2957, 2853, 2806, 1578, 1477, 1451, 1116, 1021,
738, 691, 467 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.51–7.47 (m, 2 H), 7.29–7.26 (m,
3 H), 6.68 (dt, J = 9.26 and 1.18 Hz, 1 H), 6.09 (dt, J = 9.26 and
6.32 Hz, 1 H), 3.74 (t, J = 4.70 Hz, 4 H), 3.09 (dd, J = 6.32 and 1.18
Hz, 2 H), 2.59–2.49 (m, 4 H).
MS (EI): m/z (%) = 306 (24) [M+], 277 (13), 207 (20), 199 (41), 129
(60), 77 (100), 51 (44).
13C NMR (50 MHz, CDCl3): d = 132.01, 131.42, 129.15, 128.48,
127.08, 125.37, 66.86, 58.40, 53.35.
[(Z)-2-(Phenylselanyl)vinyl]benzene (3g)
MS (EI): m/z (%) = 283 (17) [M+], 202 (25), 157 (4), 126 (100), 95
(20), 77 (19), 56 (39), 42 (37).
Mp 43.5–45 °C (Lit.39 44–45 °C).
IR (KBr): 3050, 3020, 1740, 1690, 1610, 1500, 1480, 1430, 1075,
730, 640 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.59–7.54 (m, 2 H), 7.40–7.36 (m,
4 H), 7.20–7.35 (m, 4 H), 6.97 (d, J = 10.40 Hz, 1 H), 6.77 (d,
J = 10.40 Hz, 1 H).
13C NMR (50 MHz, CDCl3): d = 137.1, 132.6, 131.5, 130.0, 129.2,
128.3, 128.2, 127.5, 127.2, 123.8.
4-[(2Z)-3-(Phenyltellanyl)prop-2-en-1-yl]morpholine (3l)
IR (KBr): 3062, 2854, 2814, 1594, 1574, 1451, 1432, 1116, 1032,
733, 694, 456 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.73–7.71 (m, 2 H), 7.25–7.20 (m,
3 H), 7.08 (dt, J = 9.40 and 1.50 Hz, 1 H), 6.47 (dt, J = 9.40 and
4.39 Hz, 0.98 H), 3.79 (t, J = 4.70 Hz, 4 H), 2.96 (dd, J = 4.39 and
1,50 Hz, 2 H), 2.52–2.46 (m, 4 H).
MS (EI): m/z (%) = 260 (5) [M+], 258 (6), 179 (52), 158 (22), 103
(26), 91 (51), 77 (100), 51 (45).
13C NMR (50 MHz, CDCl3): d = 137.18, 130.74, 128.95, 127.17,
120.98, 112.72, 66.93, 59.67, 53.14.
[(Z)-2-(Phenyltellanyl)vinyl]benzene (3h)
MS (EI): m/z (%) = 333 (11) [M+], 207 (3), 126 (100), 117 (50), 100
(65), 77 (52), 56 (53).
Mp 40–42.5 °C (Lit.40 40–42 °C).
IR (KBr): 3050, 3015, 1767, 1597, 1489, 1426, 1016, 769, 656
cm–1.
HRMS (ESI): m/z [M]+ calcd for C13H17NOTe: 334.0445; found:
334.0448.
1H NMR (200 MHz, CDCl3): d = 7.81–7.75 (m, 2 H), 7.48 (d,
J = 10.6 Hz, 1 H), 7.44–7.20 (m, 8 H), 7.09 (d, J = 10.6 Hz, 1 H).
13C NMR (50 MHz, CDCl3): d = 138.8, 137.9, 136.8, 129.3, 128.4,
128.0, 127.4, 127.3, 115.3, 109.15.
(2Z)-N,N-Dibenzyl-3-(phenylselanyl)prop-2-en-1-amine (3m)
IR (KBr): 3060, 3027, 2920, 2795, 1598, 1574, 1453, 1120, 1072,
737, 697, 464 cm–1.
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C. C. Silveira et al.
PAPER
Marcantoni, E.; Sambri, L.; Torregiani, E. J. Org. Chem.
1H NMR (200 MHz, CDCl3): d = 7.47–7.17 (m, 15 H), 6.60 (dt,
J = 9.05 and 1.22 Hz, 1 H), 6.18 (dt, J = 9.05 and 6.24 Hz, 1 H),
3.59 (s, 4 H), 3.15 (dd, J = 6.24 and 1.22 Hz, 2 H).
13C NMR (50 MHz, CDCl3): d = 139.23, 131.89, 131.37, 131.32,
129.14, 128.92, 128.15, 126.95, 126.86, 123.70, 58.03, 53.60.
MS (EI): m/z (%) = 393 (2) [M+], 312 (11), 236 (35), 157 (4), 144
(42), 115 (30), 91 (100), 77 (13), 65 (35), 51 (15).
HRMS (ESI): m/z [M]+ calcd for C23H23NSe: 394.1068; found:
394.1068.
2003, 68, 4594.
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De Nino, A.; Sambri, L.; Tagarelli, A. Eur. J. Org. Chem.
2000, 99. (b) Liu, H. J.; Shia, K. S.; Shang, X.; Zhu, B. Y.
Tetrahedron 1999, 55, 3803.
(6) (a) Comasseto, J. V.; Ling, L. W.; Petragnani, N.; Stefani, H.
A. Synthesis 1997, 373. (b) Comasseto, J. V.; Barrientos-
Astigarraga, R. E. Aldrichimica Acta 2000, 33, 66.
(c) Vieira, M. L.; Zinn, F. K.; Comasseto, J. V. J. Braz.
Chem. Soc. 2001, 12, 586. (d) Lüdtke, D. S.; Panatieri, R.
B.; Braga, A. L.; Zeni, G. Chem. Rev. 2006, 106, 1032.
(e) Aggarwal, V. K.; Winn, C. L. Acc. Chem. Res. 2004, 37,
611. (f) Tang, Y.; Ye, S.; Sun, X. L. Synlett 2005, 2720.
(g) Perin, G.; Lenardão, E. J.; Jacob, R. G.; Panatieri, R. B.
Chem. Rev. 2009, 109, 1277.
(7) (a) Petragnani, N. Tellurium in Organic Synthesis;
Academic Press: London, 1994. (b) Petragnani, N.
Tellurium, In Comprehensive Organometallic Chemistry II,
Vol. 11; Abel, E. W.; Stone, F. G. A.; Wilkinson, G., Eds.;
Pergamon: New York, 1994, Chap. 14. (c) Whitham, G. H.
Organosulfur Chemistry; Oxford University Press: Oxford,
1995. (d) Organoselenium Chemistry: Modern
(2Z)-N,N-Dibenzyl-3-(phenyltellanyl)prop-2-en-1-amine (3n)
IR (KBr): 3061, 3026, 2922, 2797, 2709, 1596, 1574, 1295, 1119,
1069, 1028, 732, 697, 454 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.71–7.66 (m, 2 H), 7.38–7.19 (m,
13 H), 7.03 (dt, J = 9.41 and 1.12 Hz, 1 H), 6.53 (dt, J = 9.41 and
5.59 Hz, 1 H), 3.58 (s, 4 H), 3.04 (dd, J = 5.59 and 1.12 Hz, 2 H).
13C NMR (50 MHz, CDCl3): d = 138.34, 137.36, 135.58, 129.42,
129.21, 128.13, 127.46, 126.97, 116.24, 110.94, 68.76, 57.45.
MS (EI): m/z (%) = 443 (4) [M+], 236 (31), 207 (2), 144 (56), 115
(30), 91 (100), 77(31), 65 (35), 51 (25).
HRMS (ESI): m/z [M]+ calcd for C23H23NTe: 444.0965; found:
444.0965.
Developments in Organic Synthesis; Wirth, T., Ed.;
Springer: Berlin, 2000. (e) Organoselenium Chemistry: A
Practical Approach; Back, T. G., Ed.; Oxford University
Press: Oxford, 1999. (f) The Chemistry of Organic Selenium
and Tellurium Compounds, Volume 1; Patai, S.; Rappoport,
Z., Eds.; Wiley: Chichester, 1986. (g) The Chemistry of
Organic Selenium and Tellurium Compounds, Volume 2;
Patai, S.; Rappoport, Z., Eds.; Wiley: Chichester, 1987.
(h) Organoselenium Chemistry; Liotta, D., Ed.; Wiley-
Interscience: New York, 1987.
Acknowledgment
The authors thank FAPERGS, CAPES, and MCT/CNPq for finan-
cial support and Prof. N. P. Lopes from FCFRP-USP for HRMS
analysis.
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