Highly selective perfluoroalkylchalcogenation of alkynes by the combination of iodoperfluoroalkanes and organic dichalcogenides upon photoirradiation

Article abstract of DOI:10.1016/j.tet.2012.09.026

Vinylic selenides and tellurides are useful synthetic intermediates for preparation of vinylic compounds and carbonyl compounds. Herein we report highly selective perfluoroalkylselenation and -telluration of terminal alkynes by using heteroatom mixed systems, i.e., (PhSe)₂/R_fI and (PhTe)₂/R_fI, upon photoirradiation. When the reaction of aromatic alkynes and conjugated enynes with diphenyl diselenide and perfluoroalkyl iodide is conducted in benzotrifluoride (BTF) as solvent upon irradiation with a xenon lamp through Pyrex (hν >300 nm), novel perfluoroalkylselenation of the alkynes takes place regio- and stereoselectively to give 1-(perfluoroalkyl)-2-(phenylseleno)alkenes in good yields. Similar procedure can be applied to photoinduced perfluoroalkyltelluration of aromatic alkynes, and perfluoroalkyl and phenyltelluro groups are introduced to the terminal and internal positions of alkynes regio- and stereoselectively. Since perfluoroalkyl (fluorous) groups make it possible to isolate the products easily by fluorous/organic/aqueous extraction technique, the obtained perfluoroalkylselenation and -telluration products are promising as synthetic intermediates.

Full text of DOI:10.1016/j.tet.2012.09.026

Tetrahedron 68 (2012) 10516e10522
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Highly selective perfluoroalkylchalcogenation of alkynes by the combination
of iodoperfluoroalkanes and organic dichalcogenides upon photoirradiation
Taichi Tamai, Akihiro Nomoto, Kaname Tsuchii, Yoshiaki Minamida, Takenori Mitamura,
*
Motohiro Sonoda, Akiya Ogawa
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 29 June 2012
Received in revised form 30 August 2012
Accepted 4 September 2012
Available online 11 September 2012
Vinylic selenides and tellurides are useful synthetic intermediates for preparation of vinylic compounds
and carbonyl compounds. Herein we report highly selective perfluoroalkylselenation and -telluration of
terminal alkynes by using heteroatom mixed systems, i.e., (PhSe)2/RfI and (PhTe)2/RfI, upon photo-
irradiation. When the reaction of aromatic alkynes and conjugated enynes with diphenyl diselenide and
perfluoroalkyl iodide is conducted in benzotrifluoride (BTF) as solvent upon irradiation with a xenon
lamp through Pyrex (hn >300 nm), novel perfluoroalkylselenation of the alkynes takes place regio- and
Keywords:
stereoselectively to give 1-(perfluoroalkyl)-2-(phenylseleno)alkenes in good yields. Similar procedure
can be applied to photoinduced perfluoroalkyltelluration of aromatic alkynes, and perfluoroalkyl and
phenyltelluro groups are introduced to the terminal and internal positions of alkynes regio- and ster-
eoselectively. Since perfluoroalkyl (fluorous) groups make it possible to isolate the products easily by
fluorous/organic/aqueous extraction technique, the obtained perfluoroalkylselenation and -telluration
products are promising as synthetic intermediates.
Dichalcogenide
Perfluoroalkyl iodide
Radical reactions
Photoirradiation
Alkynes
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
thioselenation with (PhS)2 and (PhSe)2 upon photoirradiation
(Eq. 2).6
Radical addition reactions of heteroatom compounds to un-
saturated compounds are one of the most useful methods for in-
troduction of heteroatom functions into organic molecules.1 Along
this line, we have recently developed a series of photoinduced
radical addition reactions of organoselenium and tellurium com-
pounds, such as organic diselenides and ditellurides to unsaturated
compounds.2 For example, organic diselenides and ditellurides add
to alkynes upon photoirradiation under higher concentration of the
starting materials to afford the corresponding vicinal diseleno- and
ditelluroalkenes, respectively (Eq. 1).3,4
hν (>300 nm)
R1
PhSe
R1
(PhS)2, (PhSe)2
40-45 oC, 30 h
(2)
SPh
The excellent regioselectivity observed in this reaction is based
on the kinetic control: (i) Thio radicals are much more reactive
toward carbonecarbon unsaturated compounds compared with
seleno radicals; (ii) Diselenides indicate excellent carbon radical
trapping ability compared with disulfides. Therefore, the thio rad-
ical formed in situ upon photoirradiation selectively attacks alkenes
and the resulting carbon radicals are selectively captured with the
diselenide.
R
YAr
hν
R
+
(ArY)2
(1)
ArY
Y = Se, Te
The photoinduced thioselenation with (PhS)2 and (PhSe)2 can be
applied to a wide range of unsaturated compounds, such as al-
kynes,7 allenes,8 conjugate dienes,9 and vinylcyclopropanes.10 For
example, alkynes undergo regioselective thioselenation to give the
In contrast to the radical addition of organic diselenides and
ditellurides to alkynes, the corresponding radical addition to al-
kenes is a very inefficient process. However, we have developed
a series of heteroatom mixed systems, which provide powerful
tools to heteroatom compounds having two different heteroatom
functions.5 For example, a variety of alkenes undergo regioselective
corresponding
b
-phenylthio-substituted vinyl selenides in high
yields (Eq. 3).7
(PhS)2-(PhSe)2
hν (>300 nm)
CHCl3, 40-45 oC
R
SPh
R
(3)
* Corresponding author. Tel./fax: þ81 72 254 9290; e-mail address: ogawa@
PhSe
chem.osakafu-u.ac.jp (A. Ogawa).
0040-4020/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2012.09.026

T. Tamai et al. / Tetrahedron 68 (2012) 10516e10522
10517
R
hν
hν
The thioselenation methodology can be applied to the photo-
Rf
Rf
Rf – I
Rf – I
Rf – I
R
+
+
+
induced thiotelluration and selenotelluration of alkynes by use of
disulfideeditelluride and diselenideeditelluride mixed systems
(Eqs. 4 and 5).10
I
R
R
(PhS) -(PhTe)
hν (>400 nm)
2
2
I
R
SPh
R
ν
h
Rf
R
R
(4)
o
CHCl , 45 C
3
PhTe
I
R
R
hν
I
Rf – I
Rf – I
Rf – I
+
+
+
Rf
(PhSe) -(PhTe)
hν (>400 nm)
R
R
2
2
R
SePh
ν
h
I
(5)
R
o
R
CHCl , 45 C
3
PhTe
R
C
Rf
ν
h
Next, we have developed photoinduced introduction of two
different heteroatom groups to carbonecarbon unsaturated bonds
by novel combination of group 16 and group 15 heteroatom com-
pounds. Thus, photoinduced selenophosphination of alkynes has
been attained by the combination of diphenyl diselenide and tet-
raphenyldiphosphine (Eq. 6).11 In the selenophosphination of ter-
minal alkynes, the seleno and phosphino groups are introduced to
the terminal and internal positions of alkynes, regioselectively.
I
Rf
R
R
Rf
I
hν
Rf – I
+
R
N
R
N
Scheme 1.
(PhSe)2-(Ph2P)2
hν (>350 nm)
R
SePh
air, r.t.
2. Result and discussion
2.1. Photoinduced perfluoroalkylselenation of alkynes
R
CHCl3, r.t., 1 h
overnight
Ph2P
(6)
O
When the reaction of phenylacetylene with equimolar amounts
of henicosafluoro-n-decyl iodide and diphenyl diselenide was
conducted in benzotrifluoride (BTF)16 as organic/fluorous hybrid
solvent upon irradiation with a xenon lamp through Pyrex, the
desired perfluoroalkylselenation product was obtained in 26% yield
along with the diselenide adduct to the alkyne (55%, E/Z¼75/25)
(Table 1, entry 1). Formation of the diselenide adduct concerns with
the competition of PhSeꢀ addition and Rꢀf addition to alkynes. To
depress the formation of the diselenide adduct, lower concentra-
tion of (PhSe)2 is preferred.
Furthermore, the combination of diphenyl ditelluride and tet-
raphenyldiphosphine leads to novel phosphinotelluration of al-
kynes. Interestingly, the phosphino and telluro groups are
introduced to the terminal and internal carbons of terminal alkynes
(Eq. 7).12 Based on these results, it has been estimated that the
relative reactivities of heteroatom-centered radicals toward car-
bonecarbon unsaturated bonds are as follows: PhSeꢀ>Ph2Pꢀ>PhTeꢀ.
O
(PhTe) -(Ph P)
2
2
2
R
PPh
2
h
ν
(>400 nm)
(7)
R
CHCl , r.t., 10 h
PhTe
3
Table 1
Perfluoroalkylselenation under several conditions
n
These reactions clearly demonstrate the efficacy of the
heteroatom-mixed systems for the highly selective introduction of
two heteroatom functions into organic molecules. During the
course of our studies on the radical addition reactions of hetero-
atom compounds to unsaturated compounds, we have next ex-
amined the combination of group 16 and group 17 heteroatoms.
Recently, we have also investigated the photoinduced radical
addition of perfluoroalkyl iodides to a series of unsaturated com-
pounds, such as alkynes, allenes, alkenes, conjugated dienes,
methylenecyclopropanes, vinylcyclopropanes, and isocyanides,13
and their application to radical cyclization reactions14 (Scheme 1).
The obtained perfluoroalkyliodination products are useful as
synthetic intermediates, because the obtained iodides can be
replaced conveniently by a variety of carbon- and heteroatom
groups. In addition, perfluoroalkyl (fluorous) groups make it pos-
sible to isolate the products easily by fluorous/organic/aqueous
extraction technique.
C10F21
Ph
hν (>300 nm)
n
(PhSe)2
Ph
C10F21
I
+
+
BTF, 40 oC, 10 h
PhSe
Entry
Ph
, equiv
(PhSe)2, equiv
BTF, mL
Yielda, %
1
2
3
4
5
1.00
0.33
1.00
1.00
2.00
1.00
0.33
0.24
0.24
0.12
0.12
0.24
26
29
50
85
82
1.00 (three times)
3.00 (nine times)
2.00 (six times)
Determined by 1H NMR.
a
In this reaction, perfluoroalkyliodination product to alkynes was
not obtained. The carbon radical capturing ability of diphenyl dis-
elenide is reported to be 1.2ꢁ107 Mꢂ1 sꢂ1 based on the radical clock
system of 5-hexenyl radical.17 We also estimated roughly the car-
bon radical capturing ability of perfluoroalkyl iodide, such as
henicosafluoro-n-decyl iodide similarly by using the 5-hexenyl
radical clock system (Eq. 8).
In this paper, we wish to report a highly selective photoinduced
perfluoroalkylselenation15 and -telluration of terminal alkynes by
use of novel mixed systems of group 16 and group 17 heteroatom
compounds.

10518
T. Tamai et al. / Tetrahedron 68 (2012) 10516e10522
Table 2
hν (>300 nm)
Perfluoroalkylselenation of terminal alkynesa
n
+
C10F21
I
n
BTF, 10 h, r.t.
C10F21
R
hν
n
(PhSe)2
+
+
R
C10F21
I
BTF, 40 oC, 10 h
PhSe
+
n
C10F21
n
(8)
I
I
C10F21
Entry
R
Product
Yieldb, %
21%
27%
n
C10F21
The result indicates that the carbon radical capturing ability of
perfluoroalkyl iodide is 2.6ꢁ105 Mꢂ1 sꢂ1. These kinetic data clearly
indicate that (PhSe)2 has excellent carbon-radical-capturing ability
compared with RfI. Therefore, it is possible to reduce the concen-
tration of (PhSe)2. Thus, we examined the reaction by the addition
of the diselenide separately in three positions during photo-
irradiation, and the yield of the perfluoroalkylselenation product
was improved (50%) (entry 3). Furthermore, when excess amounts
of (PhSe)2 were added separately in 6e9 times, the per-
fluoroalkylselenation products were obtained selectively in good
yields (entries 4 and 5).
Similar condition, such as entry 5 in Table 1 can be employed
with aromatic acetylenes bearing an electron-donating group (1b
and 1c) or an electron-withdrawing group (1d) at the p-position,
and the corresponding perfluoroalkylselenation products (2b, 2c,
and 2d) were obtained in good yields successfully (Table 2, entries
2e4). In these reactions, perfluoroalkyl and phenylseleno groups
are introduced to the terminal and internal positions, respectively,
and only (E)-isomers are obtained stereoselectively. In the case of 1-
ethynylcyclohexene as a conjugated enyne (1e), the desired per-
fluoroalkylselenation reaction also proceeded efficiently (entry 5).
In the case of aliphatic alkynes, such as 1-dodecyne, however,
the reaction did not proceed at all. The difference in the reactivity of
aromatic and aliphatic alkynes is most probably owing to the dif-
ference in the stability of the corresponding vinylic radical in-
termediates. In general, vinylic radicals generated from aliphatic
1
2
3
82
PhSe
1a
2a
nC10F21
Me
Me
81
85
63
PhSe
1b
1c
1d
2b
n
C5H11
n
C10F21
n
C5H11
PhSe
2c
Br
n
C10F21
Br
4
PhSe
2d
n
C10F21
5
71
alkynes form
tween (E)- and (Z)-isomers),18 whereas
radicals are assumed to be
-radicals,19 which are more stable
compared with the -radicals from aliphatic alkynes.
s
-radicals (which are in very fast equilibrium be-
PhSe
1e
a-aryl-substituted vinylic
2e
p
s
nC10F21I (0.1 mmol), acetylene (2 equiv), (PhSe)2 (2 equiv), hv: xenon lamp
a
The perfluoroalkylselenation of ethyl propiolate requires long
period of reaction time. In the case of silylacetylene, most of the
starting alkynes were recovered unchanged. The attempted per-
fluoroalkylselenation of vinyl monomers, such as n-butyl vinyl
ether failed, because the polymerization of vinyl monomers took
place preferentially.
(Pyrex).
b
NMR yield.
A possible pathway for the present perfluoroalkylselenation
may involve the following: (i) (PhSe)2 mainly undergoes homolytic
cleavage upon photoirradiation to generate PhSeꢀ, because the ab-
sorption of (PhSe)2 is stronger than that of RfI (Fig. 1); (ii) The
formed seleno radical abstracts iodine atom from RfI to generate Rꢀf;
(iii) Rꢀf attacks the terminal carbon of alkynes to form vinylic radical
intermediates; (iv) The formed vinyl radical intermediates are
trapped selectively by (PhSe)2 to give the perfluoroalkylselenation
products (Scheme 2).
The initiation step is strongly supported by the fact that the
present perfluoroalkylselenation could proceed upon irradiation
with the light of wavelength over 400 nm (upon irradiation for
1.5 h, the perfluoroalkylselenation product was obtained in 44%
yield).
abs.
λmax = 270 nm
εmax = 4.9 x 10
n
C10F21
I
λmax = 330 nm
εmax = 1 x 103
(PhSe)2
(PhTe)2
= 406 nm
λmax
ε
max = 8 x 102
n
(in C6H14
)
2.2. Photoinduced perfluoroalkyltelluration of alkynes
250
300
400
500
nm
We next examined the application of the perfluoroalkylselenation
procedure to perfluoroalkyltelluration of alkynes, because vinyl tel-
lurides are useful starting materials for the formation of vinyl anions
n
Fig. 1. UV-visible spectra of C10F21I, (PhSe)2 and (PhTe)2.

T. Tamai et al. / Tetrahedron 68 (2012) 10516e10522
10519
Table 4
(PhSe)
2
Perfluoroalkyltelluration with several solventsa
R
f
n
C6F13
h
υ
Ar
hν (> 400 nm)
I
R
f
Ph
n
Ph
C6F13
I
+
(PhTe)2 +
SePh
solvent, 13 h
PhSe
PhTe
3a
1a
PhSe
I
Yieldb
(PhSe)
Entry
Solvent (0.5 mL)
2
1
2
3
4
5
6
7
8
9
Neat
23%
22%
68%
45%
24%
26%
41%
41%
7%
CH3OH
CD3CN
DMF
Acetone
CDCl3
BTF
Ar
R
f
R
f
THF
Benzene
a
Phenylacetylene (0.1 mL), (PhTe)2 (0.02 mmol), nC6F13I (0.01 mmol), hv: high
Ar
pressure Hg lamp through a filter (>400 nm).
b
Determined by 1H NMR.
Scheme 2.
The perfluoroalkyltelluration proceeded in various solvents, such as
protic solvents, aprotic and polar solvents, and aprotic nonpolar
solvents. Among the solvents employed, acetonitrile is the best
solvent for the perfluoroalkyltelluration (entry 3).
Under the optimized reaction conditions, the per-
fluoroalkyltelluration of phenylacetylene was conducted using
several perfluoroalkyl iodides (Eq. 9).
by tellurium-lithium exchange reaction.20 Moreover, transition-
metal-catalyzed cross coupling reactions using vinyl tellurides are
reported.21
As can be seen from Fig. 1, diphenyl ditelluride has its absorption
maximum in visible region, and therefore the per-
fluoroalkyltelluration was conducted upon visible light irradiation.
Compared with the perfluoroalkylselenation, the corresponding
perfluoroalkyltelluration is somewhat difficult to take place, be-
cause of the relatively lower stability of the product tellurides to-
ward photoirradiation. Therefore, we first optimized the reaction
conditions of the perfluoroalkyltelluration using phenylacetylene
as the substrate. The perfluoroalkyltelluration of phenylacetylene
requires the use of excess amounts (ca. 8e10 equiv) of the alkyne.
Rf
h
ν (> 400 nm)
Ph
PhTe
(9)
Ph
(PhTe)2
+
Rf
I
+
CD3CN (0.5 mL)
13 h
n
Rf = C4F9
n
52%
55%
49%
C8F17
Table
3 indicates the results of the photoinduced per-
n
C10F21
fluoroalkyltelluration of phenylacetylene by varying the molar ra-
tios of phenylacetylene/(PhTe)2/nC6F13I. As the results, when the
molar ratio of phenylacetylene/(PhTe)2/nC6F13I is 0.91 (0.1 mL)/
0.02/0.01, the perfluoroalkyltelluration product was obtained in
good yield (entry 3). The perfluoroalkyl and phenyltelluro groups
are introduced to the terminal and internal positions of phenyl-
pentafluorophenyl
no reaction
Both light and heavy fluorous iodides (perfluoroalkyl iodides)
can be utilized for perfluoroalkyltelluration. However, penta-
fluorophenyl iodide did not afford the corresponding adduct at all.
The relatively stronger CeI bond energy of pentafluorophenyl io-
dide may contribute to the inefficiency in radical addition reaction.
The photoinduced perfluoroalkyltelluration of various terminal
alkynes using (PhTe)2/RfI mixed systems was examined, and the
results are shown in Table 5.
acetylene,
respectively,
and
(E)-isomer
was
obtained
stereoselectively.
Table 3
Varying molar ratio of perfluoroalkyltelluration
A variety of aromatic alkynes underwent regio- and stereo-
selective perfluoroalkyltelluration.22 In the cases of aromatic al-
kynes having strong electron-withdrawing groups, such as nitro
and cyano groups at the p-position, the yields of the desired per-
fluoroalkyltelluration products were lower (entries 6 and 7). Ali-
phatic alkynes also underwent perfluoroalkyltelluration to give the
corresponding fluorous vinylic tellurides in moderate yields (en-
tries 8 and 9). In the cases of electron-deficient alkynes, such as
ethyl propiolate, small amounts of the perfluoroalkyltelluration
product were obtained regio- and stereoselectively (entry 10).
The present photoinduced perfluoroalkyltelluration may pro-
ceed via similar pathways (Scheme 3) as mentioned in the per-
fluoroalkylselenation of alkynes. Therefore, homolytic cleavage of
TeeTe single bond of the ditelluride by visible light irradiation
generates PhTeꢀ. The formed telluro radical abstracts iodine atom
from perfluoroalkyl iodide to generate Rꢀf,23 which adds to alkynes.
The formed vinylic radicals are trapped selectively with (PhTe)2 to
give the corresponding perfluoroalkyltelluration products. The
stereochemistry is determined when vinyl radical intermediates
are trapped by (PhTe)2. The steric effect between Rf group and
n
C6F13
hν (> 400 nm)
CD3CN (0.5 mL)
Ph
n
Ph
C6F13
I
+
(PhTe)2 +
PhTe
Entry
Acetylene, mL
(PhTe)2, mmol
RfI, mmol
Yielda, %
1
2
3
4
5
6
0.10
0.10
0.10
0.05
0.10
0.10
0.01
0.01
0.02
0.02
0.03
0.03
0.01
0.02
0.01
0.01
0.01
0.02
12
51
68
37
40
31
a
Determined by 1H NMR.
Under the conditions of entry 3 in Table 3, the yields of the
perfluoroalkyltelluration versus the times of photoirradiation were
as followed: 41% (4 h); 57% (8 h); 68% (13 h); 64% (15 h).
Next, we examined the perfluoroalkyltelluration of phenyl-
acetylene in several solvents, and the results are shown in Table 4.

10520
T. Tamai et al. / Tetrahedron 68 (2012) 10516e10522
hν
Table 5
Rf – I
Perfluoroalkyltelluration of terminal alkynesa
+
(PhTe)2
PhTe
PhTe – I
Rf
n
C6F13
Rf
R
R
Rf
hν
n
+
(PhTe)2
(PhTe)2
– PhTe
+
R
Entry
1
R
C6F13
I
1
R
R
Rf
CD3CN, 13 h
PhTe
Rf
1
3
PhTe
3
R
Product
Yieldb, %
(PhTe)2
Rf
(PhTe)2
n
C6F13
R
R
68
70
Rf
Ph Te
Ph Te
PhTe
1a
3a
TePh
TePh
Me
n
C6F13
less favored
Me
Scheme 3.
2
PhTe
3b
1b
(PhTe)2 in the transition state to give (Z)-isomer may contribute to
the excellent E selectivity.
MeO
n
C6F13
MeO
3
4
56
40
3. Conclusion
PhTe
3f
1f
In summary, the highly selective perfluoroalkylselenation and
-telluration of terminal alkynes have been attained by using
a mixed system of perfluoroalkyl iodide and diphenyl diselenide (or
diphenyl ditelluride). The formed of vinylic selenides and tellurides
are useful precursors for generation vinylic anions24 and vinylic
organometallics. Furthermore, perfluoroalkyl groups (Rf) are im-
portant fluorous tags, and make it possible to separate products
easily by extraction. Further study along these lines is now in
progress.
Cl
n
C6F13
Cl
PhTe
3g
1g
F
n
C6F13
F
5
6
7
50
11
8
PhTe
3h
1h
4. Experimental section
n
O2N
C6F13
4.1. General procedure for the synthesis of (E)-perfluoro-1-
(phenylseleno)-1-aryl-1-dodecene
O2N
PhTe
3i
In a Pyrex glass tube were placed alkyne (0.20 mmol) and per-
fluoroalkyl iodide (0.10 mmol) in BTF (0.05 mL). The mixture was
irradiated with a xenon lamp (500 W) at 40 ꢃC for 10 h, and during
the irradiation, diphenyl diselenide (62.4 mg, 0.20 mmol) was
added separately six portions (i.e., total of 0.20 mmol of (PhSe)2 was
added). After the reaction was complete, the corresponding per-
fluoroalkylselenation product as a single stereoisomer (E-isomer),
was formed in good yield. Products were purified by recycling
preparative HPLC.
1i
NC
n
C6F13
NC
PhTe
3j
1j
n
C6F13
4.1.1. (E)-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Henicosafluoro-
1-(phenylseleno)-1-phenyl-1-dodecene (2a). Pale yellow oil; 1H NMR
8
9
26
PhTe
3k
1k
(300 MHz, CDCl3):
d
5.28 (t, J¼14.3 Hz, 1H), 7.34 (s, 5H), 7.36e7.45
(m, 3H), 7.62e7.66 (m, 2H). 13C NMR (75 MHz, CDCl3):
d
110.9 (t,
n
C6F13
JCeF¼97.2 Hz, 1H), 127.5, 127.9, 128.0, 128.3, 128.9, 129.1, 129.9, 130.0,
136.5, 136.8, 153.9. IR (NaCl): 3059, 3028, 3017, 1632, 1441, 1244,
1215, 1155, 756, 669 cmꢂ1. HRMS calcd for C24H11F21Se: 777.9690;
found: 777.9686.
19
6
PhTe
3l
1l
n
C6F13
O
O
4.1.2. (E)-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Henicosafluoro-
1-(phenylseleno)-1-(4-methylphenyl)-1-dodecene (2b). Pale yellow
O
O
10
oil; 1H NMR (300 MHz, CDCl3):
d
2.35 (s, 3H), 5.24 (t, JHeF¼14.2 Hz,
1H), 7.13e7.25 (m, 4H), 7.36e7.44 (m, 3H), 7.63e7.65 (d, J¼7.8 Hz,
2H). 13C NMR (75 MHz, CDCl3):
21.4, 110.6, 127.0, 127.8, 128.0, 128.7,
129.5, 129.8, 130.0, 133.5, 136.8, 139.0. 19F NMR (373 MHz, CDCl3):
ꢂ126.1, ꢂ122.7, ꢂ121.7, ꢂ121.4, ꢂ117.7, ꢂ105.0, ꢂ102.8, ꢂ96.7,
ꢂ86.4, ꢂ80.8. IR (NaCl): 3032, 2924, 2870, 1635, 1508, 1439, 1373,
PhTe
1m
3m
d
a
nC6F13I (0.01 mmol), acetylene (excess), (PhTe)2 (2 equiv), hv: high pressure Hg
d
lamp through a filter (>400 nm).
b
NMR yield.

T. Tamai et al. / Tetrahedron 68 (2012) 10516e10522
10521
1339, 1211, 1149, 891, 817, 740, 690, 636 cmꢂ1. HRMS (FAB) calcd for
732 cmꢂ1. HRMS (FAB) calcd for C21H14F13OTe [MþH]þ: 658.9899;
C25H14F21Se [MþH]þ: 792.9925; found: 792.9936.
found: 658.9885.
4.1.3. (E)-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Henicosafluoro-
1-(phenylseleno)-1-(4-pentylphenyl)-1-dodecene (2c). Pale yellow
4.2.4. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
(4-chlorophenyl)-1-octene (3g). 1H NMR (400 MHz, CDCl3):
d 5.61
oil; 1H NMR (300 MHz, CDCl3):
d
0.84e0.91 (m, 3H), 1.25e1.40 (m,
(t, JHeF¼14.6 Hz, 1H), 7.19e7.29 (m, 4H), 7.38e7.44 (m, 3H), 7.94 (d,
4H),1.53e1.67 (m, 2H), 2.55e2.66 (m, 2H), 5.26 (t, JHeF¼14.6 Hz, 1H),
J¼8.2 Hz, 2H).
7.11e7.15 (m, 3H), 7.35e7.34 (m, 2H), 7.63 (d, J¼8.2 Hz, 2H), 7.74 (d,
J¼7.8 Hz, 2H). 13C NMR (75 MHz, CDCl3):
d
14.0, 22.6, 30.9, 31.6, 35.8,
4.2.5. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
(4-fluorophenyl)-1-octene (3h). Pale yellow oil; 1H NMR (400 MHz,
110.6, 127.0, 128.0, 128.9, 129.5, 130.0, 130.7, 136.8, 138.2, 144.0. 19F
NMR (373 MHz, CDCl3):
d
ꢂ126.1, ꢂ122.7, ꢂ121.7, ꢂ121.4, ꢂ117.7,
CDCl3):
d
5.58 (t, JHeF¼14.2 Hz, 1H), 6.93e7.03 (m, 2H), 7.20e7.31
ꢂ105.0, ꢂ102.8, ꢂ96.7, ꢂ86.4, ꢂ80.8. IR (NaCl): 2959, 2928, 2854,
1717, 1639, 1439, 1362, 1211, 1150, 1110, 1072, 744, 640 cmꢂ1. HRMS
(FAB) calcd for C29H22F21Se [MþH]þ: 849.0551; found: 849.0526.
(m, 2H), 7.40e7.50 (m, 3H), 7.81 (d, J¼8.2 Hz, 2H). 13C NMR
(100 MHz, CDCl3):
d 114.9, 118.2, 125.7, 128.8, 129.0, 129.8, 129.9,
130.2, 140.8, 141.0. 19F NMR (373 MHz, CDCl3):
d
ꢂ126.1, ꢂ123.1,
ꢂ121.6, ꢂ113.1, ꢂ107.0, ꢂ103.1, ꢂ80.7. IR (NaCl): 3059, 2959, 2924,
2851, 1635, 1596, 1504, 1434, 1365, 1234, 1199, 1141, 837, 736,
690 cmꢂ1. HRMS (FAB) calcd for C20H11F14Te [MþH]þ: 646.9699;
found: 646.9667.
4.1.4. (E)-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Henicosafluoro-
1-(phenylseleno)-1-(4-bromophenyl)-1-dodecene (2d). White solid;
mp 83.6e85.0 ꢃC; 1H NMR (300 MHz, CDCl3):
d
5.32 (t, JHeF¼14.2 Hz,
1H), 7.14e7.21 (m, 3H), 7.36e7.49 (m, 2H), 7.61 (d, J¼8.2 Hz, 2H), 7.75
(d, J¼7.3 Hz, 2H). 13C NMR (75 MHz, CDCl3):
d
111.7, 123.2, 128.5,
4.2.6. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
129.5, 130.1, 130.7, 131.2, 135.4, 136.8, 138.1. 19F NMR (373 MHz,
(4-nitrophenyl)-1-octene (3i). 1H NMR (400 MHz, CDCl3):
d 5.91 (t,
CDCl3):
d
ꢂ126.1, ꢂ122.7, ꢂ121.7, ꢂ117.7, ꢂ113.0, ꢂ105.1, ꢂ103.0,
JHeF¼14.2 Hz, 1H), 7.38e7.42 (m, 3H), 7.62e7.77 (m, 2H), 7.89 (d,
ꢂ97.4, ꢂ86.4, ꢂ80.8. IR (NaCl): 3067, 2924, 1643, 1585, 1481, 1435,
1207, 1150, 1072, 1011, 744 cmꢂ1. HRMS (FAB) calcd for C24H11BrF21Se
[MþH]þ: 856.8874; found: 856.8884.
J¼7.8 Hz, 2H), 8.10e8.31 (m, 2H).
4.2.7. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
(4-cyanophenyl)-1-octene (3j). 1H NMR (400 MHz, CDCl3):
d 5.85 (t,
4.2. General procedure for the synthesis of (E)-perfluoro-1-
(phenytelluro)-1-aryl-1-octene
JHeF¼14.2 Hz, 1H), 7.37e7.41 (m, 3H), 7.51e7.70 (m, 4H), 7.97 (d,
J¼8.2 Hz, 2H).
In a NMR tube were placed alkyne (0.1 mL), perfluoroalkyl io-
dide (0.01 mmol) and diphenyl ditelluride (8.2 mg, 0.02 mmol) in
CD3CN (0.5 mL). The mixture was irradiated with a high pressure
4.2.8. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
butyl-1-octene (3k). Pale yellow oil; 1H NMR (400 MHz, CDCl3):
d
0.88 (t, J¼7.25 Hz, 3H), 1.33 (m, 4H), 2.54 (t, J¼7.7 Hz, 2H), 5.48 (t,
Hg lamp through a glass filter (h
n
>400 nm) at room temperature
JHeF¼14.2 Hz, 1H), 7.26e7.41 (m, 3H), 7.20e7.31 (m, 2H), 7.82 (d,
for 13 h. After the reaction was complete, the corresponding per-
fluoroalkyltelluration product as a single stereoisomer (E-isomer),
was formed in moderate yield. Products were purified by extraction
with FC-72.
J¼8.8 Hz, 2H). 13C NMR (100 MHz, CDCl3):
d 13.8, 22.3, 33.0, 36.6,
112.9, 119.2, 129.5, 130.0, 141.0, 142.0. 19F NMR (373 MHz, CDCl3):
d
ꢂ126.0, ꢂ123.4, ꢂ122.8, ꢂ121.6, ꢂ104.3, ꢂ80.7. IR (NaCl): 3058,
2962, 2869, 2341, 1663, 1616, 1477, 1438, 1361, 1238, 1203, 1145,
1099, 1064, 1022, 736, 690, 667 cmꢂ1
.
4.2.1. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
phenyl-1-octene (3a). Pale yellow oil; 1H NMR (400 MHz, CDCl3):
4.2.9. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
(3-methylbutyl)-1-octene (3l). Pale yellow oil; 1H NMR (400 MHz,
d
5.53 (t, JHeF¼14.2 Hz, 1H), 7.22e7.32 (m, 5H), 7.36e7.57 (m, 3H),
7.83e7.85 (d, J¼6.7 Hz, 2H). 13C NMR (100 MHz, CDCl3):
d
98.9,115.1,
CDCl3):
d
0.86 (d, J¼6.0 Hz, 6H), 1.24 (m, 1H), 1.46 (m, 2H), 2.54 (t,
126.8, 127.8, 128.2, 128.7, 129.7, 130.1, 132.5, 141.0. 19F NMR
J¼8.0 Hz, 2H), 5.50 (t, JHeF¼14.2 Hz, 1H), 7.25e7.41 (m, 3H), 7.83 (d,
(373 MHz, CDCl3):
d
ꢂ126.1, ꢂ123.1, ꢂ122.9, ꢂ121.6, ꢂ103.2, ꢂ80.7.
J¼7.8 Hz, 2H). 13C NMR (100 MHz, CDCl3):
d 22.3, 28.1, 34.9, 39.6,
IR (NaCl): 3055, 2927, 2854, 1242, 1200, 1142, 1961, 737, 691 cmꢂ1
.
112.9, 119.0, 129.5, 130.0, 141.1, 142.1. 19F NMR (373 MHz, CDCl3):
HRMS (FAB) calcd for C20H12F13Te [MþH]þ: 628.9794; found:
d
ꢂ126.1, ꢂ123.4, ꢂ122.8, ꢂ121.6, ꢂ104.6, ꢂ80.7. IR (NaCl): 3070,
2958, 2931, 2873, 1620, 1573, 1469, 1434, 1365, 1238, 1203, 1145,
1118, 1064, 1018, 999, 914, 844, 810, 779, 732, 694, 640 cmꢂ1
628.9803.
.
4.2.2. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
(4-methylphenyl)-1-octene (3b). Pale yellow oil; 1H NMR (400 MHz,
4.2.10. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
(ethoxycarbonyl)-1-octene (3m). 1H NMR (400 MHz, CDCl3):
1.23
CDCl3):
d
5.48 (t, JHeF¼14.2 Hz, 1H), 7.08e7.25 (m, 5H), 7.29e7.45
d
(m, 2H), 7.83e7.88 (d, J¼7.9 Hz, 2H). 13C NMR (100 MHz, CDCl3):
(t, J¼6.9 Hz, 3H), 4.35 (q, J¼7.3 Hz, 2H), 5.86 (t, JHeF¼14.2 Hz, 1H),
d
21.3,115.3,117.5,123.8, 126.8, 128.4, 128.6, 129.7,130.1,136.1,140.9.
7.26e7.39 (m, 3H), 8.00 (d, J¼8.2 Hz, 2H).
19F NMR (373 MHz, CDCl3):
d
ꢂ126.1, ꢂ123.1, ꢂ122.9, ꢂ121.6, ꢂ103.1,
ꢂ80.7. IR (NaCl): 3055, 2920, 2851, 1362, 1238, 1200, 1142, 1119, 841,
813, 775.3, 736.8, 687 cmꢂ1. HRMS (FAB) calcd for C21H14F13Te
[MþH]þ: 642.9950; found: 642.9942.
Acknowledgements
This work was supported by a Grant-in-Aid for Scientific Re-
search on Scientific Research (C, 23550057), from the Ministry of
Education, Culture, Sports, Science and Technology of Japan.
4.2.3. (E)-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-(phenyltelluro)-1-
(4-methoxyphenyl)-1-octene (3f). Pale yellow oil; 1H NMR
(400 MHz, CDCl3):
d
3.80 (s, 3H), 5.51 (t, JHeF¼14.2 Hz, 1H), 6.81 (d,
J¼7.8 Hz, 2H), 7.12e7.35 (m, 5H), 7.84 (d, J¼7.8 Hz, 2H). 13C NMR
References and notes
(100 MHz, CDCl3):
d 55.3, 113.0, 118.0, 123.5, 126.7, 128.3, 128.8,
130.0, 130.1, 140.4, 144.5. 19F NMR (373 MHz, CDCl3):
d
ꢂ126.1,
1. (a) Kochi, J. K. Free Radicals; Wiley: New York, NY, 1973; Vol. II; (b) Radicals in
Organic Synthesis; Renaud, P., Sibi, M. P., Eds.; Wiley-VCH: Weinheim, 2001; (c)
Handbook of Reagents for Organic Synthesis; Crich, D., Ed.; Wiley & Sons: Wilt-
shire, 2008.
ꢂ123.1, ꢂ122.9, ꢂ121.4, ꢂ102.9, ꢂ80.7. IR (NaCl): 3055, 2958, 2928,
2855, 1604, 1508, 1439, 1242, 1203, 1141, 1110, 1033, 833, 806, 779,

10522
T. Tamai et al. / Tetrahedron 68 (2012) 10516e10522
2. (a) Nomoto, A.; Ogawa, A. In The Chemistry of Organic Selenium and Tellurium
Compounds; Rappoport, Z., Ed.; John Wiley & Sons Ltd: Chichester, UK, 2012;
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22. The regioselectivity of the perfluoroalkyltelluration products could be de-
termined unambiguously by the coupling constant JHeF of vinylic proton. The
vinylic proton at the
whereas the vinylic proton at the
a
-position of Rf group appears triplet (JHeF¼14.2 Hz),
b
-position of Rf group becomes singlet. On
the other hand, determination of the stereochemistry of the per-
fluoroalkyltelluration products was performed based on NOE experiments, as
shown below. Similarly, the regio- and stereoselectivities of per-
fluoroalkylselenation products were determined by the same methods.
NOE (16%)
n
C6F13
H
H
H
NOE (2%)
n
H
H
C6F13
6. Ogawa, A.; Tanaka, H.; Yokoyama, H.; Obayashi, R.; Yokoyama, K.; Sonoda, N. J.
Org. Chem. 1992, 57, 111e115.
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PhTe
7. Ogawa, A.; Obayashi, R.; Ine, H.; Tsuboi, Y.; Sonoda, N.; Hirao, T. J. Org. Chem.
1998, 63, 881e884.
H
8. Ogawa, A.; Obayashi, R.; Doi, M.; Sonoda, N.; Hirao, T. J. Org. Chem. 1998, 63,
4277e4281.
(E)-3l
(Z)-3l
9. Ogawa, A.; Obayashi, R.; Sonoda, N.; Hirao, T. Tetrahedron Lett. 1998, 39,
1577e1578.
vinylic proton: triplet (JH-F = 14.2 Hz)
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1999, 64, 86e92.
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n
TePh
H
C10F21
NOE (3%)
H
H
n
C6F13
Se
regioisomer of (E)-3l
H
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vinylic proton: singlet
(E)-2d
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23. During the photoirradiated reactions of alkynes with RfI and (PhTe)2 (or
(PhSe)2), PhTeI (or PhSeI) and RfTePh (or RfSePh) may be formed in situ. To get
some information about these species, we examined the photoirradiated re-
action of RfI with (PhTe)2 (or (PhSe)2) in the absence of alkynes, and the re-
actions were monitored by 125Te (or 77Se) and 19F NMR. In the case of (PhTe)2,
the signal of (PhTe)2 disappeared within 3 h, but no new peak was observed in
125Te NMR. This was probably due to the formation of aggregated mixture of
PhTeI. In the case of (PhSe)2, most of the diselenide remained unchanged after
photoirradiation for 3 h.
24. Generation of vinyl anions from vinyl tellurides can be performed upon
treatment with BuLi in THF at ꢂ78 ꢃC, and the stereochemistry of the formed
vinyl anions retains at the temperature.
21. Zeni, G.; Braga, A. L.; Stefani, H. A. Acc. Chem. Res. 2003, 36, 731e738.