Synthesis of 1-alkynyl(diphenyl)onium salts of group 16 elements via heteroatom transfer reaction of 1-alkynyl(phenyl)-λ3-iodanes

Article abstract of DOI:10.1039/b212512a

1-Alkynyl(phenyl)-λ³-iodanes undergo selective transfer of the alkynyl groups over the phenyl group onto diphenyl chalcogens. Exposure of 1-alkynyl(phenyl)-λ³-iodanes to diphenyl chalcogens (S, Se, and Te) in dichloromethane or 1,2-d

Full text of DOI:10.1039/b212512a

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Synthesis of 1-alkynyl(diphenyl)onium salts of group 16 elements
3
via heteroatom transfer reaction of 1-alkynyl(phenyl)-ꢀ -iodanes
Masahito Ochiai,* Takema Nagaoka, Takuya Sueda, Jie Yan, Da-Wei Chen and
Kazunori Miyamoto
Faculty of Pharmaceutical Sciences, University of Tokushima, 1-78 Shomachi,
Tokushima 770-8505, Japan. E-mail: mochiai@ph2.tokushima-u.ac.jp
Received 17th December 2002, Accepted 6th March 2003
First published as an Advance Article on the web 27th March 2003
3
1
-Alkynyl(phenyl)-λ -iodanes undergo selective transfer of the alkynyl groups over the phenyl group onto diphenyl
3
chalcogens. Exposure of 1-alkynyl(phenyl)-λ -iodanes to diphenyl chalcogens (S, Se, and Te) in dichloromethane or
,2-dichloroethane affords 1-alkynyl(diphenyl)sulfonium, -selenonium, and -telluronium salts in high yields.
1
6
Introduction
with reductive elimination of iodobenzene. Use of a catalytic
amount of Cu() or Cu() salts accelerates the phenyl transfer
reaction to such an extent that the reaction proceeds at tem-
peratures as low as 120–130 ЊC. Photochemical reaction of
diphenyl-λ -iodanes with diphenyl sulfide in acetonitrile at room
temperature results in the formation of triphenylsulfonium salts
through a single electron transfer process. The alkenyl group in
E)- and (Z)-1-alkenyl(phenyl)-λ -iodanes 5 was selectively
transferred to diphenyl sulfide by the reaction with diisopropyl-
ethylamine to give a mixture of stereoisomers of alkenyl-
diphenyl)sulfonium tetrafluoroborate 7. The involvement of
free alkylidene carbene 6 via base-induced reductive α-elimin-
ation of 5 was firmly established by the high degree of stereo-
convergence of the olefin geometry in this alkenyl transfer
reaction (Scheme 2).
Efficient methods available for the synthesis of 1-alkynyl-
(
aryl)onium salts of group 15 and 16 elements are limited.
7
In 1987 we reported that the heteroatom transfer reaction
between 1-alkynyl(phenyl)-λ -iodanes and triphenylphosphine
provides a useful tool for the synthesis of 1-alkynyl(triphenyl)-
phosphonium salts. The method was applied for the synthesis
3
3
8
1
3
(
of 1-alkynyl(triphenyl)arsonium salts, but not for that of
2
1
-alkynyl(triphenyl)stibonium and -bismuthonium salts,
probably because of the low nucleophilicity of triphenylstibine
and triphenylbismuthine compared to triphenylphosphine and
triphenylarsine.
9
(
3
Silane–, germane–, stannane–, or borane–hypervalent
λ -iodane exchange in the presence of a Lewis acid provides an
3
3
efficient route for the synthesis of 1-alkynyl(aryl)-λ -iodanes:
thus, reaction of alkynyl(trimethyl)silane with iodosylbenzene
3
in the presence of BF –Et O affords alkynyl(phenyl)-λ -iodanes
3
2
1,4
in high yields under mild conditions. The exchange reaction
was applied to the synthesis of alkynyl(diphenyl)selenonium
and -telluronium salts: diphenyl(phenylethynyl)selenonium or
5
-
telluronium salt was prepared by the Si–Se() exchange reac-
tion of (phenylethynyl)trimethylsilane with diphenyl selenoxide
in the presence of trifluoromethanesulfonic anhydride or by the
BF -promoted ligand exchange of (phenylethynyl)tributyl-
stannane with diphenyltellurinyl difluoride, respectively.
3
Scheme 2
Herein, we report a general method for the synthesis of
-alkynyl(diphenyl)sulfonium 2, -selenonium 3, and -telluron-
The results of alkynyl transfer reactions between 1-alkynyl-
phenyl)-λ -iodanes 1 and diphenyl chalcogens are summar-
3
1
3
4
(
ium salts 4, which involves a heteroatom transfer reaction
3
ized in Table 1. Exposure of 1-decynyl(phenyl)-λ -iodane 1c to
diphenyl sulfide in dichloromethane at room temperature for 48
h showed no evidence for an alkynyl transfer reaction; however,
when a solution of 1c and diphenyl sulfide (1.2 equiv) in 1,2-
dichloroethane was heated at 83 ЊC for 26 h, the 1-decynyl
group of 1c was selectively transferred to diphenyl sulfide,
and 1-decynyl(diphenyl)sulfonium tetrafluoroborate 2c was
obtained in 90% yield (Entry 7). Reaction times required for the
alkynyl transfer in 1,2-dichloroethane at 83 ЊC depend on the
differences in the steric demands of the alkyl substituents (R)
attached to the acetylenic carbon atom in 1 and increase in the
between 1-alkynyl(phenyl)-λ -iodanes 1 and diphenyl chalco-
gens under mild conditions (Scheme 1). In this reaction, the
3
1
-alkynyl group of the λ -iodanes 1 was selectively transferred
to the chalcogen atoms in preference to the phenyl group.
n
order of increasing steric hindrance: Me (1b, 12 h) < C H (1c,
8
17
i
t
2
6 h) < Pr (1d, 45 h) < Bu (1e, 168 h) (Entries 4, 7, 12, and
1
5). Ethynylation of diphenyl sulfide with the least sterically
3
Scheme 1
demanding ethynyl-λ -iodane 1a takes place at room temper-
ature in dichloromethane (3 h). Phenylethynyl-λ -iodane 1g
3
also undergoes transfer of the phenylethynyl group to diphenyl
sulfide without heating (Entry 20). Alkynylation of the more
nucleophilic dialkyl sulfide occurs smoothly; thus, the reaction
of dibutyl sulfide with 1c afforded the alkynylsulfonium salt 8 at
room temperature (2.5 h) quantitatively (Scheme 3).
Results and discussion
3
Diphenyl-λ -iodane (Ph IBF ), on heating at 185 ЊC without
2
4
using a solvent, undergoes oxidative phenyl group transfer to
diphenyl sulfide to give triphenylsulfonium tetrafluoroborate
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 5 1 7 – 1 5 2 1
1517

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3
Table 1 Alkynyl transfer reaction between 1-alkynyl(phenyl)-λ -
takes place at room temperature. The rate of alkynyl transfer of
to diphenyl selenide also decreases with increasing steric
demand of the alkynyl group in the order MeCC (1b) >
a
iodanes 1 and diphenyl chalcogens
1
Conditions
Product
n
i
t
C H CC (1c) > PrCC (1d) > BuCC (1e) (Entries 5, 9, 10, 13,
8
17
3
b
c
and 16). Thus, our 1-alkynyl transfer reaction provides an
efficient route for the synthesis of 1-alkynyl(diphenyl)sulfonium
Entry
λ -Iodane 1
Ph X
Temp./ЊC
Time/h
(Yield, %)
2
2
, -selenonium 3 and -telluronium salts 4.
1
2
3
4
5
6
7
8
9
1a
1a
1a
1b
1b
1b
1c
1c
1c
1c
1c
1d
1d
1d
1e
1e
1e
1f
Ph2S
25
25
25
83
40
25
83
25
40
83
25
83
83
25
83
83
25
25
25
25
25
25
1
2
2a (100)
3a (96)
4a (90)
2b (83)
3b (86)
4b (91)
Ph Se
Because of the powerful electron-withdrawing nature of the
2
3
Ph Te
3.5
12
15.5
0.5
26
48
29
2
phenyl-λ -iodanyl group Ph(BF )I— with a large Hammett
substituent constant (σ : 1.37), alkynyl-λ -iodanes 1 are highly
electron-deficient species. They act as good Michael acceptors
toward a variety of soft nucleophiles, including stable eno-
lates of 1,3-dicarbonyl compounds, oxygen (carboxylate and
phenoxide), nitrogen (azide and amide), sulfur (sulfinate and
thiocyanate) and halide nucleophiles. Michael addition of
diphenyl chalcogens to the β-carbons of alkynyl-λ -iodanes 1,
followed by reductive elimination of iodobenzene, will generate
alkylidene carbenes. A subsequent 1,2-shift in the alkylidene
carbenes results in the formation of the alkynyl(diphenyl)-
onium salts 2–4. This mechanism explains both formation of
the onium salts 2–4 and the relative rates of the transfer reac-
2
4
d
Ph2S
11
3
p
Ph Se
12
2
Ph Te
2
d
Ph2S
2c (90)e
Ph Se
3c (30)
2
Ph Se
3c (86)
3c (98)
4c (100)
2d (66)
3d (78)
4d (85)
2e (56)
3e (93)
4e (98)e
3f (89)
4f (100)
2g (89)
3g (85)
4g (87)
2
d
d
13
10
11
12
13
14
15
16
17
18
19
20
21
22
Ph Se
2
Ph Te
3
3
2
d
Ph2S
45
12
5
168
88
3
39
2
19
34
2
Ph Se
2
Ph Te
2
d
Ph2S
d
f
Ph Se
2
Ph Te
2
Ph Se
n
i
2
tion that decrease in the order of Me (1b) > C H (1c) > Pr
8 17
t
1f
Ph Te
2
(
1d) > Bu (1e). Michael attack of diphenyl chalcogens on
3
1g
1g
1g
Ph2S
alkynyl-λ -iodanes 1 will be inhibited by a sterically demanding
alkyl group (R) at the β-position, which slows down the rate of
the alkynyl transfer reaction.
Ph Se
2
Ph Te
2
a
Reactions were carried out in dichloromethane under nitrogen,
unless otherwise noted. 1.2 equiv of Ph X were used. Isolated yields.
1
b
c
To gain some insight into the mechanism of this transfer
2
13
3
d
e
reaction, phenyl(phenylethynyl-2- C)-λ -iodane 12 (99%
13a
,2-Dichloroethane was used as a solvent. Yields were determined by
1
f
H NMR. 5 equiv of Ph Se were used.
enriched)
was synthesized and subjected to the alkynyl
13
2
transfer reaction with diphenyl telluride (Scheme 5). The
C
enrichment at the β-acetylenic carbon of the resulting
(
9
phenylethynyl)telluronium salt 13 was found to be greater than
8% from the C NMR spectrum. The reaction with diphenyl
13
13
selenide gave a similar result, i.e. C enrichment of more
than 95% at the β-acetylenic carbon of the resulting (phenyl-
ethynyl)selenonium tetrafluoroborate. The well-known high
Scheme 3
13a,e
migratory aptitude of α-aryl groups in alkylidene carbenes
The attempted direct alkynylation of thioanisole was
seems to suggest that the tandem Michael–alkylidene car-
bene mechanism involving generation of the reactive inter-
mediate 14 may result in the predominant formation of the
(phenylethynyl-1- C)telluronium salt through a facile 1,2-
phenyl shift, instead of affording 13. Although there is no
experimental and theoretical evidence, it seems reasonable to
assume that the migratory aptitude of the positively charged
diphenyltelluronium group to the electron-deficient carbenic
centre may be lower than that of the phenyl group.
accompanied by further methyl transfer reaction of the result-
ing alkynylsulfonium salt 11; thus, treatment of 1c with thio-
anisole (2.5 equiv) in dichloromethane at 40 ЊC gave a mixture
of 1-decynyl phenyl sulfide 9 (88%) and dimethyl(phenyl)-
sulfonium tetrafluoroborate 10 (95%) (Scheme 4). Nucleophilic
attack of thioanisole on the initially formed decynyl(methyl)-
13
(
phenyl)sulfonium salt 11 probably transfers the methyl group
to thioanisole and produces the sulfonium salt 10 with form-
10
ation of the sulfide 9. Because of the decreased nucleophilicity
of the sulfide 9 relative to thioanisole, the reverse methyl
transfer from 10 to 9 will not take place under the conditions.
Scheme 5
Scheme 4
An alternative ligand coupling mechanism on iodine() of
the telluronium salt 15, produced by ligand exchange via the
nucleophilic attack of diphenyl telluride at the positively
charged iodine of 12, may account for the selective formation
of the telluronium salt 13. A similar mechanism has been pro-
3
No transfer reaction between the alkynyl-λ -iodanes 1 and
oxygen nucleophiles was observed; even under prolonged heat-
ing in 1,2-dichloroethane, large amounts of the λ -iodane 1c
and diphenyl ether were recovered unchanged. This is probably
due to the low nucleophilicity of diphenyl ether compared to
diphenyl sulfide. More nucleophilic diphenyl selenide and tellur-
ide react with the alkynyl-λ -iodanes 1 under mild conditions to
give the alkynylselenonium 3 and -telluronium salts 4 in high
yields (Table 1); for instance, even the reaction of diphenyl
telluride with the bulky 3,3-dimethyl-1-butynyl-λ -iodane 1e
3
3
posed for the reaction of alkynyl(phenyl)-λ -iodanes 1 with
2
triphenylarsine.
3
Whatever the mechanism, the method is attractive from the
practical standpoint, because of its mildness, cleanliness, and
the ease with which the alkynyl(diphenyl)onium salts 2–4 can be
isolated. The results presented suggest that the alkynyl transfer
3
1
518
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 5 1 7 – 1 5 2 1

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3
reaction between 1-alkynyl(phenyl)-λ -iodanes 1 and diphenyl
3,3-Dimethyl-1-butynyl(diphenyl)sulfonium tetrafluoroborate
chalcogens takes place selectively under mild conditions.
2e. Colourless needles (from dichloromethane–diethyl ether);
mp 144–145 ЊC {Found: C, 60.58, H, 5.25%; HRMS (FAB),
2
67.1211. Calc. for C H BF Sؒ¼H O: C, 60.27; H, 5.48%;
18 19 4 2
ϩ Ϫ1
Experimental
[M Ϫ BF ] , 267.1207}; ν
(nujol)/cm 2975, 2200, 1450,
4
max
1
150–1000, 750 and 690; δ (200 MHz; CDCl ) 8.18–8.06 (4 H,
General
H
3
m), 7.76–7.64 (6 H, m) and 1.45 (9 H, s).
IR spectra were recorded on JASCO IRA-1 and Perkin Elmer
1
13
1
720 FT-IR spectrometers. H and C NMR were recorded on
Diphenyl(phenylethynyl)sulfonium
tetrafluoroborate
2g.
ϩ
JEOL FX-200 and JMN-GCX 400 spectrometers. Chemical
shifts are reported in parts per million (ppm) downfield
from internal Me Si. Mass spectra (MS) were obtained on
a JEOL JMS-DX300 spectrometer. Melting points were
determined with a Yanaco micro melting points apparatus
and are uncorrected. Preparative thin-layer chromatography
Reddish oil {HRMS (FAB) Calc. for C H S: ([M Ϫ BF ] ),
20
15
4
Ϫ1
2
1
87.0894. Found: m/z, 287.0893}; νmax (neat)/cm 2184, 1474,
446, 1150–1000, 754 and 685; δ (400 MHz; CDCl ) 8.17 (4 H,
4
H
3
d, J 7.5), 7.81 (2 H, d, J 7.7), 7.77–7.64 (6 H, m), 7.60 (1 H, t,
J 7.4) and 7.48 (2 H, dd, J 7.7 and 7.4).
(
TLC) was carried out on precoated plates of silica gel (Merck,
Diphenyl(ethynyl)selenonium tetrafluoroborate 3a. Oil
silica gel F-254). Dichloromethane and 1,2-dichloroethane
were dried over CaH and distilled under nitrogen. Diphenyl
sulfide and selenide, dibutyl sulfide and thioanisole are
commercially available. Diphenyl telluride was prepared
according to the reported method. 1-Alkynyl(phenyl)-λ -
iodanes 1 and 12 were prepared from the corresponding
1
ϩ
80
{
2
2
HRMS (FAB) Calc. for C H Se: ([M Ϫ BF ] , Se),
14 11 4
Ϫ1
2
59.0026. Found: m/z, 259.0005}; νmax (neat)/cm 3231, 3064,
063, 1476, 1446, 1150–1000, 743 and 682; δH (400 MHz;
CD OD) 7.94 (4 H, d, J 7.5), 7.64–7.75 (6 H, m) and 4.92 (1 H,
14
3
3
s). Selenonium salt 3a is labile and contaminated with a small
amount of impurity.
-alkynyl(trimethyl)silanes by reaction with iodosylbenzene in
the presence of BF –Et O in dichloromethane according to the
literature procedure.
3
2
4
Diphenyl(1-propynyl)selenonium tetrafluoroborate 3b. Colour-
less leaflets (from dichloromethane–hexane); mp 184–186 ЊC
{
Found: C, 49.83, H, 3.76%; HRMS (FAB), 273.0172. Calc. for
General procedure for synthesis of 1-alkynyl(diphenyl)onium
ϩ 80
C H BF Se: C, 50.18; H, 3.65%; [M Ϫ BF ] , Se, 273.0182};
15
13
4
4
tetrafluoroborates 2–4. To a stirred solution of a 1-alkynyl-
Ϫ1
3
3
ν
6
max (KBr)/cm 3048, 2204, 1567, 1441, 1150–1000, 739 and
80; δ (200 MHz; CD OD) 8.0–7.9 (4 H, m), 7.72–7.6 (6 H, m)
(
phenyl)-λ -iodane 1 (0.2 mmol) in 2 cm of dichloromethane
or 1,2-dichloroethane was added diphenyl chalcogen
0.24 mmol) under nitrogen, and the solution was stirred under
H
3
a
and 2.35 (3 H, s); δC (100 MHz; CDCl ) 134.4, 133.3, 132.5,
1
3
(
30.9, 110.8, 56.6 and 5.1.
the conditions shown in Table 1. The solvent was evaporated
under reduced pressure to give an oil, which was washed several
times with dichloromethane–hexane or –diethyl ether by decan-
tation at Ϫ78 ЊC to give 1-alkynyl(diphenyl)onium salt 2–4.
Yields of the products are given in Table 1.
1
-Decynyl(diphenyl)selenonium tetrafluoroborate 3c. 80 Oil
ϩ
{
3
1
HRMS (FAB) Calc. for C H Se: ([M Ϫ BF ] , Se),
22 27 4
Ϫ1
71.1264. Found: m/z, 371.1279}; νmax (nujol)/cm 2920, 2190,
440, 1150–1000 and 745; δ (200 MHz; CDCl ) 8.0–7.9 (4 H,
H
3
m), 7.65–7.54 (6 H, m), 2.67 (2 H, t, J 7.5), 1.70 (2 H, quint,
J 7.5), 1.5–1.1 (10 H, m) and 0.88 (3 H, t, J 6.6); δ (100 MHz;
CDCl ) 133.5, 131.5, 130.1, 129.4, 116.1, 54.2, 31.6, 28.9, 28.7,
8.7, 27.2, 22.5, 20.2 and 13.9.
Diphenyl(ethynyl)sulfonium tetrafluoroborate 2a. Pale yellow
ϩ
C
oil {HRMS (FAB) Calc. for C H S: ([M Ϫ BF ] ), 211.0582.
14
11
4
Ϫ1
3
Found: m/z, 211.0597}; νmax (neat)/cm 3222, 3095, 2076, 1616,
448, 1150–1000, 748 and 682; δH (400 MHz; CDCl ) 8.13
2
1
3
(
(
4 H, d, J 7.3), 7.78 (2 H, t, J 7.3), 7.72 (4 H, t, J 7.3) and 4.54
1 H, s).
Diphenyl(3-methyl-1-butynyl)selenonium tetrafluoroborate 3d.
Colourless needles (from dichloromethane–hexane); mp 137–
ϩ
80
1
3
1
41 ЊC {HRMS (FAB) Calc. for C H Se: ([M Ϫ BF ] , Se),
17 17 4
Ϫ1
Diphenyl(1-propynyl)sulfonium tetrafluoroborate 2b. Colour-
01.0495. Found: m/z, 301.0508}; νmax (nujol)/cm 2960, 2190,
450, 1160–1000, 750 and 680; δ (200 MHz; CDCl ) 8.00–7.85
less needles (from dichloromethane–hexane); mp 127–129 ЊC
Found: C, 57.69, H, 4.43%; HRMS (FAB), 225.0747. Calc.
{
H
3
ϩ
(4 H, m), 7.70–7.54 (6 H, m), 3.03 (1 H, sept, J 7.0) and 1.37
(6 H, d, J 7.0); δ (100 MHz; CDCl ) 133.5, 131.5, 130.1, 129.5,
for C H BF S: C, 57.71; H, 4.20%; [M Ϫ BF ] , 225.0738};
15
13
4
4
Ϫ1
νmax (nujol)/cm 3222, 2210, 1460, 1435, 1150–1000, 740 and
75; δ (200 MHz; CDCl ) 8.20–8.00 (4 H, m), 7.80–7.48 (6 H,
C
3
1
20.2, 54.2, 22.3 and 21.5.
6
H
3
m) and 2.43 (3 H, s); δ (100 MHz; CDCl ) 134.8, 131.7, 129.3,
C
3
3
,3-Dimethyl-1-butynyl(diphenyl)selenonium tetrafluoroborate
1
27.7, 113.9, 53.0 and 5.9.
3
e. Colourless prisms (from dichloromethane–hexane); mp
ϩ
1
78–182 ЊC {HRMS (FAB) Calc. for C H Se: ([M Ϫ BF ] ,
18 19 4
Ϫ1
1
-Decynyl(diphenyl)sulfonium tetrafluoroborate 2c. Oil
80
ϩ
Se), 315.0652. Found: m/z, 315.0628}; νmax (nujol)/cm 2960,
2200, 2170, 1445, 1160–1100, 750 and 680; δH (200 MHz;
CDCl ) 8.04–7.88 (4 H, m), 7.72–7.52 (6 H, m) and 1.43 (9 H,
{
HRMS (FAB) Calc. for C H S: ([M Ϫ BF ] ), 323.1833.
Found: m/z, 323.1865}; νmax (neat)/cm 2910, 2205, 1440,
150–1000, 750 and 680; δ (200 MHz; CDCl ) 8.20–8.02 (4 H,
22
27
4
Ϫ1
1
3
H
3
s); δ (100 MHz; CDCl ) 133.5, 131.5, 130.2, 129.4, 122.6, 53.9,
9.9 and 29.6.
m), 7.72–7.60 (6 H, m), 2.78 (2 H, t, J 7.2), 1.73 (2 H, quint,
C
3
2
J 7.2), 1.54–1.05 (10 H, m) and 0.86 (3 H, t, J 6.6); δ (100 MHz;
C
CDCl ) 134.8, 131.7, 129.3, 127.9, 117.3, 54.2, 31.6, 29.0, 28.9,
3
2
8.8, 27.0, 22.5, 20.5 and 14.0.
Diphenyl(trimethylsilylethynyl)selenonium tetrafluoroborate
ϩ 80
3
f. Oil {HRMS (FAB) Calc. for C H SeSi: ([M Ϫ BF ] , Se),
17 19 4
Ϫ1
Diphenyl(3-methyl-1-butynyl)sulfonium tetrafluoroborate 2d.
331.0421. Found: m/z, 331.0428}; νmax (neat)/cm 3036, 2064,
1477 and 1100–1000; δ (200 MHz; CDCl ) 8.04–7.88 (4 H, m),
Colourless needles (from dichloromethane–hexane); mp 153–
H
3
ϩ
1
2
1
56 ЊC {HRMS (FAB) Calc. for C H S: ([M Ϫ BF ] ),
7.75–7.55 (6 H, m) and 0.37 (9 H, s). The onium salt 3f is highly
labile.
17
17
4
Ϫ1
53.1051. Found: m/z, 253.1059}; νmax (nujol)/cm 2970, 2200,
450, 1150–1000, 770 and 690; δ (200 MHz; CDCl ) 8.16–8.04
H
3
5a
(
4 H, m), 7.76–7.60 (6 H, m), 3.13 (1 H, sept, J 6.8) and 1.39 (6
Diphenyl(phenylethynyl)selenonium tetrafluoroborate 3g.
δ (100 MHz; CDCl ) 133.6, 133.2, 132.4, 131.6, 130.1, 129.7,
H, d, J 6.8); δ (100 MHz; CDCl ) 134.8, 131.8, 129.3, 127.8,
C
3
C
3
1
20.9, 54.0, 22.4 and 21.1.
129.0, 117.7, 111.0 and 63.4.
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 5 1 7 – 1 5 2 1
1519

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ϩ
Diphenyl(ethynyl)telluronium tetrafluoroborate 4a. Colourless
prisms (from dichloromethane–hexane); mp 153–157 ЊC;
νmax (KBr)/cm 3247, 2048, 1909, 1440, 1150–1000, 734 and
(FAB) Calc. for C H S: ([M Ϫ BF ] ), 283.2459. Found: m/z,
18 35 4
Ϫ1
283.2495}; νmax (nujol)/cm 2925, 2220, 1470 and 1150–
1000; δH (200 MHz; CDCl ) 3.8–3.5 (4 H, m), 2.58 (2 H, t,
Ϫ1
3
6
85; δ (200 MHz; CD OD) 7.96–7.8 (4 H, m), 7.62–7.48 (6 H,
J 7.0), 1.92 (4 H, quint, J = 7.0), 1.8–1.2 (16 H, m), 1.0 (6 H, t,
H
3
ϩ
130
m), 4.05 (1 H, s); FAB MS m/z 309 ([M Ϫ BF ] , Te, 100%),
J 7.0) and 0.88 (3 H, t, J 7.0); δ (100 MHz; CDCl ) 111.8, 54.4,
4
C
3
ϩ
128
ϩ 126
3
07 ([M Ϫ BF ] , Te, 92), 305 ([M Ϫ BF ] , Te, 62).
46.4, 31.6, 29.0, 28.8, 28.7, 27.1, 26.6, 22.5, 21.1, 20.0, 13.9 and
3.3.
4
4
1
Diphenyl(1-propynyl)telluronium tetrafluoroborate 4b. Colour-
less prisms (from dichloromethane–hexane); mp 222–225 ЊC
Found: C, 43.06, H, 3.19%; HRMS (FAB), 323.0060. Calc. for
3
Reaction of 1-decynyl-ꢀ -iodane 1c with thioanisole. To a
3
{
stirred solution of 1-decynyl(phenyl)-λ -iodane 1c (86 mg,
0.20 mmol) in dichloromethane (2 cm ) was added thioanisole
(62 mg, 0.50 mmol) under nitrogen at room temperature, and
the solution was refluxed for 47 h. The solvent was evaporated
under reduced pressure. Decantation of the reaction mixture
with dichloromethane–hexane at Ϫ78 ЊC gave dimethyl-
ϩ
130
3
C H BF Teؒ½H O: C, 43.24; H, 3.39%; [M Ϫ BF ] , Te,
1
5
13
4
2
4
Ϫ1
3
23.0080}; νmax (nujol)/cm 2175, 1440, 1150–1000 and 735;
δ (200 MHz; CDCl ) 7.98 (4 H, br d, J 7.1), 7.64–7.53 (6 H, m)
H
3
and 2.30 (3 H, s); δ (100 MHz; CD OD) 135.0, 133.0, 131.5,
C
3
1
29.8, 112.2, 58.5 and 4.9.
(
phenyl)sulfonium tetrafluoroborate 10 (43 mg, 95%). The
1
-Decynyl(diphenyl)telluronium tetrafluoroborate ϩ4c.130 Oil
organic solvent was evaporated under reduced pressure to give
an oil, which was purified by preparative TLC to give 1-decynyl
{
4
2
8
HRMS (FAB) Calc. for C H Te: ([M Ϫ BF ] , Te),
22
27
4
Ϫ1
21.1172. Found: m/z, 421.1176}; νmax (neat)/cm 2910, 2850,
175, 1430, 1150–1000, 735 and 680; δH (200 MHz; CDCl3)
.2–7.9 (4 H, m), 7.62–7.45 (6 H, m), 2.59 (2 H, t, J 7.0), 1.65
phenyl sulfide 9 (43.4 mg, 88%). Compound 9: pale yellow oil
ϩ
{HRMS Calc. for C16
246.1442}; νmax (CHCl
(200 MHz; CDCl
H
22S: M, 246.1427. Found: m/z, M ,
Ϫ1
)/cm 2925, 2180, 1465 and 1090;
) 7.45–7.10 (5 H, m), 2.44 (2 H, t,
3
(
2 H, quint, J 7.0), 1.5–1.1 (10 H, m) and 0.87 (3 H, t, J 6.6);
δ
H
3
δC (100 MHz; CDCl ) 133.8, 132.6, 131.0, 125.1, 120.5, 53.7,
J 6.8), 1.7–1.1 (12 H, m) and 0.88 (3 H, t, J 6.8); m/z 246
(M , 45%), 141 (44), 125 (25), 95 (58), 81 (100). Salt 10: Colour-
3
ϩ
3
4
1.7, 29.0, 28.8, 28.8, 27.6, 22.6, 20.6 and 14.0; FAB MS m/z
ϩ
130
ϩ 128
21 ([M Ϫ BF ] , Te, 100%), 419 ([M Ϫ BF ] , Te, 95), 417
less prisms; mp 134–135 ЊC (from dichloromethane–hexane,
4
126
4
ϩ
15
(
[M Ϫ BF ] , Te, 60).
lit. mp 128–132 ЊC); δ
H
(400 MHz; CDCl ) 7.95 (2 H, br d,
3
4
J 8.5), 7.81 (1 H, br t, J 7.7), 7.73 (2 H, br dd, J 8.5 and 7.7) and
Diphenyl(3-methyl-1-butynyl)telluronium
tetrafluoroborate
3.37 (6 H, s).
4
d. Colourless prisms (from dichloromethane–hexane); mp
ϩ
13
3
1
34–138 ЊC{HRMS (FAB) Calc. for C H Te: ([M Ϫ BF ] ,
Reaction of phenyl(phenylethynyl-2- C)-ꢀ -iodane 12 with
diphenyl telluride. To a stirred solution of phenyl(phenyl-
17
17
4
130
Ϫ1
Te), 351.0393. Found: m/z, 351.0309}; νmax (nujol)/cm 2175,
440, 1150–1000 and 740; δ (200 MHz; CDCl ) 8.0–7.8 (4 H,
13
3
1
ethynyl-2- C)-λ -iodane 12 (99% enriched, 42 mg, 0.11
13a 3
H
3
m), 7.64–7.4 (6 H, m), 2.93 (1 H, sept, J 6.8) and 1.32 (6 H, d,
J 6.8); δ (100 MHz; CDCl ) 133.7, 132.6, 131.0, 125.4, 125.0,
5
mmol)
in dichloromethane (1.5 cm ) was added diphenyl
telluride (36 mg, 0.13 mmol) under nitrogen at room temper-
ature, and the solution was stirred for 15 h. The solvent was
evaporated under reduced pressure to give an oil, which was
washed several times with dichloromethane–hexane by decan-
C
3
ϩ
130
2.6, 22.4 and 21.8; FAB MS m/z 351 ([M Ϫ BF ] , Te,
00%), 349 ([M Ϫ BF ] , Te, 87), 347 ([M Ϫ BF ] , Te, 70).
4
ϩ
128
ϩ 126
1
4
4
13
3
,3-Dimethyl-1-butynyl(diphenyl)telluronium
tetrafluoro-
tation at Ϫ78 ЊC to give a diphenyl(phenylethynyl-2- C)tellur-
13
borate 4e. Colourless prisms (from dichloromethane–hexane);
mp 198–201 ЊC {Found: C, 42.32, H, 4.78%; HRMS
onium tetrafluoroborate 13 (40.8 mg, 82%) as a brown oil.
NMR signals of C1, C2 and C3 of the telluronium salt 13 in
CDCl appear at δ 63.1 (d, JC1–C2 158.1), 115.4 (s) and 119.4
C
(
FAB), 365.0565. Calc. for C H BF Te: C, 42.51; H, 4.90%;
3
18
19
4
ϩ
130
Ϫ1
13
[M Ϫ BF ] , Te, 365.0549}; νmax (nujol)/cm 2970, 2180,
(d, JC2–C3 84.6) ppm and the C enrichment at C2 of 13 was
4
2
7
150, 1460, 1160–1000, 740 and 685; δ (200 MHz; CDCl ) 8.0–
determined to be greater than 98%.
H
3
13
.85 (4 H, m), 7.6–7.44 (6 H, m) and 1.37 (9 H, s); δ (100 MHz;
In a similar manner, the reaction of (phenylethynyl-2- C)-
λ -iodane 12 with diphenyl selenide gave diphenyl(phenyl-
ethynyl-2- C)selenonium tetrafluoroborate (59%): δ
MHz; CDCl ) 110.9 (s, C2) and 63.4 (d, JC1–C2 180.1, C1). The
C enrichment at the C2 was determined to be greater than
C
3
CDCl ) 133.6, 132.6, 131.0, 128.0, 125.0, 52.1, 30.0 and 29.6;
3
ϩ
130
ϩ
13
FAB MS m/z 365 ([M Ϫ BF ] , Te, 100%), 363 ([M Ϫ BF ] ,
C
(100
4
4
128
ϩ
126
Te, 93), 361 ([M Ϫ BF ] , Te, 59).
3
4
13
Diphenyl(trimethylsilylethynyl)telluronium tetrafluoroborate
f. Pale yellow prisms (from dichloromethane–hexane); mp
95%.
4
ϩ
1
12–114 ЊC{HRMS (FAB) Calc. for C H SiTe: ([M Ϫ BF ] ,
17
19
4
References and notes
1
30
Ϫ1
Te), 381.0318. Found: m/z, 381.0293}; νmax (nujol)/cm 2030,
150, 1440, 1160–1000, 850, 740 and 690; δ (200 MHz; CDCl )
2
8
1 M. Ochiai, M. Kunishima, Y. Nagao, K. Fuji and E. Fujita, J. Chem.
Soc., Chem. Commun., 1987, 1708.
2 T. Nagaoka, T. Sueda and M. Ochiai, Tetrahedron Lett., 1995, 36,
H
3
.0–7.86 (4 H, m), 7.58–7.44 (6 H, m) and 0.30 (9 H, s); FAB
ϩ
130
ϩ
128
MS m/z 381 ([M Ϫ BF ] , Te, 100%), 379 ([M Ϫ BF ] , Te,
4), 377 ([M Ϫ BF ] , Te, 64).
4
4
2
61.
ϩ
126
9
4
3
4
(a) R. G. Pearson, H. Sobel and J. Songstad, J. Am. Chem. Soc.,
968, 90, 319; (b) D. C. Mente, J. L. Mills and R. E. Mitchell,
1
5b
Diphenyl(phenylethynyl)telluronium tetrafluoroborate 4g.
δ (100 MHz; CDCl ) 134.0, 132.9, 132.5, 131.3, 131.0, 128.7,
Inorg. Chem., 1975, 14, 123; (c) S. Ahrland, T. Berg and P. Trinderup,
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C
3
1
25.6, 119.4, 115.1 and 63.7.
(a) M. Ochiai, M. Kunishima, K. Sumi, Y. Nagao and E. Fujita,
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3
Reaction of 1-decynyl-ꢀ -iodane 1c with dibutyl sulfide. To a
3
stirred solution of 1-decynyl(phenyl)-λ -iodane 1c (86 mg,
3
0
.20 mmol) in dichloromethane (2 cm ) was added dibutyl
sulfide (35 mg, 0.24 mmol) under nitrogen at room temper-
ature, and the solution was stirred for 2.5 h. The solvent was
evaporated under reduced pressure to give an oil, which was
washed several times with hexane by decantation at Ϫ78 ЊC
to give 1-decynyl(dibutyl)sulfonium tetrafluoroborate 8 (74
mg, 100%) as a pale yellow oil. Compound 8: {HRMS
1
995, 68, 3637.
5
(a) T. Kataoka, Y. Banno, S. Watanabe, T. Iwamura and H. Shimizu,
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520
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7
(a) A. N. Nesmeyanov, L. G. Makarova and T. P. Tolstaya,
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(
b) T. Kitamura, M. Yamane, R. Furuki, H. Taniguchi and M. Shiro,
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9
S. K. Wu, J. P. Fouassier, D. Burr and J. V. Crivello, Polym. Bull.,
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988, 19, 457.
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1
1
1
0 K. Umemura, H. Matsuyama and N. Kamigata, Bull. Chem. Soc.
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9
2; (b) P. J. Stang, Angew. Chem., Int. Ed. Engl., 1992, 31, 274;
(
c) A. Varvoglis, The Organic Chemistry of Polycoordinated Iodine,
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O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 5 1 7 – 1 5 2 1
1521