Attempts to Synthesize a Thiirane, Selenirane, and Thiirene by Dealkylation of Chalcogeniranium and Thiirenium Salts

Article abstract of DOI:10.1002/chem.202003461

Thiiranium salts [Ad₂SR]⁺X^? (5, 8, 9, 11, 12; X^?=Tf₂N^? (Tf=CF₃SO₂), SbCl₆^?) and seleniranium salts [Ad₂SeR]⁺X^? (14, 16, 17, 23–25; X^?=Tf₂N^?, BF₄^?, CHB₁₁Cl₁₁^?, SbCl₆^?) are synthesized from strained alkene bis(adamantylidene) (1). The disulfides and the diselenides (Me₃SiCH₂CH₂E)₂ (4, 13), (tBuMe₂SiCH₂CH₂E)₂ (7, 22), and (NCCH₂CH₂E)₂ (10, 15; E=S, Se) have been used. The thiirenium salts [tBu₂C₂SR]⁺X^? (34) and [Ad₂C₂SR]⁺X^? (35, 36) are prepared from the bis-tert-butylacetylene (2) and bis-adamantyl-acetylene (3) with R=Me₃SiCH₂CH₂ and tBuMe₂SiCH₂CH₂. Attempts to cleave off the groups Me₃SiCH₂CH₂, tBuMe₂SiCH₂CH₂, and NCCH₂CH₂ resulted in thiiranes 27, 30. No selenirane Ad₂Se (33) is formed from seleniranium salts, instead cleavage to the alkene (1) and diselenide (13, 15) occurs. The thiirenium salt [Ad₂C₂SCH₂CH₂SiMe₃]⁺Tf₂N^? (35) does not yield the thiirene Ad₂C₂S (37), the three-membered ring is cleaved, forming the alkyne (3) and disulfide (4). All compounds are characterized by ESI mass spectra, NMR spectra, and by quantum chemical calculations. Crystal structures of the salts 8, 12, 25, 17, 26, 36 and the thiiranes 27, 30 are presented.

Full text of DOI:10.1002/chem.202003461

Accepted Article
Accepted Article
Title: Attempts to synthesize a Thiirane, Selenirane, and Thiirene by
Dealkylation of Chalcogeniranium and Thiirenium Salts.
Authors: Helmut Poleschner and Konrad Seppelt
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of the final Version of Record (VoR). This work is currently citable by
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to this Accepted Article as a result of editing. Readers should obtain
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To be cited as: Chem. Eur. J. 10.1002/chem.202003461
Link to VoR: https://doi.org/10.1002/chem.202003461
01/2020

10.1002/chem.202003461
Chemistry - A European Journal
FULL PAPER
Attempts to synthesize a Thiirane, Selenirane, and Thiirene by
Dealkylation of Chalcogeniranium and Thiirenium Salts.
Helmut Poleschner*, Konrad Seppelt[a]
Abstract: Thiiranium salts [Ad2SR]+ X– (5, 8, 9, 11, 12) (X– = Tf2N–
supporting information). Early synthetic attempts used photolysis
of 1,2,3-thiadiazoles. At best thiirenes have been characterized
by the matrix isolation technique at very low
(Tf=CF3SO2), SbCl6 ) and seleniranium salts [Ad2SeR]+ X– (14, 16, 17,
–
23–25) (X– = Tf2N–, BF4 , CHB11Cl11–, SbCl6 ) are synthesized from
strained alkene bis(adamantylidene) (1). The disulfides and the
diselenides (Me3SiCH2CH2E)2 (4, 13), (tBuMe2SiCH2CH2E)2 (7, 22),
and (NCCH2CH2E)2 (10, 15) (E = S, Se) have been used. The
thiirenium salts [tBu2C2SR]+ X– (34) and [Ad2C2SR]+ X– (35, 36) are
prepared from the bis-tert-butylacetylene (2) and bis-adamantyl-
acetylene (3) with R = Me3SiCH2CH2 and tBuMe2SiCH2CH2. Attempts
to cleave off the groups Me3SiCH2CH2, tBuMe2SiCH2CH2, and
NCCH2CH2 resulted in thiiranes 27, 30. No selenirane Ad2Se (33) is
formed from seleniranium salts, instead cleavage to the alkene (1)
and diselenide (13, 15) occurs. The thiirenium salt
[Ad2C2SCH2CH2SiMe3]+ Tf2N– (35) does not yield the thiiren Ad2C2S
(37), the three-membered ring is cleaved, forming the alkyne (3) and
disulfide (4). All compounds are characterized by ESI-mass spectra,
NMR spectra, and by quantum chemical calculations. Crystal
structures of the salts 8, 12, 25, 17, 26, 36 and the thiiranes 27, 30
are presented.
–
–
temperatures in combination with IR spectroscopy, but a
structural proof is lacking.[21] Thiirensulfoxides and Thiiren-
sulfones are known, however,[20] but attempts of deoxygenation
to thiirenes failed.[22] Our long lasting work with such unstable
three-membered ring chalcogen compounds have motivated us
to erase this white spot by new attempts. Our plan for generating
thiiranes, seleniranes, and thiirenes has been such, at first to
generate the C2-chalcogen three-membered ring motive by
electrophilic addition of an [RE+ X–] equivalent to an alkene or
alkyne under formation of chalcogeniranium and thiirenium
salts.[3-5] The positively charged S or Se atoms should bear a
cleavable group, so that after cleavage the uncharged thiiranes,
seleniranes and thiirenes should be obtained. The cleavage of a
Me3SiCH2CH2 group should be done by F–, while the NCCH2CH2
group can be cleaved of by bases such as OH–. Both are well
known protecting groups for the SH and the SeH functions[23,24]
(see Scheme 1). We wanted to test these methods by the
dealkylation reactions of thiiranium salts under formation of stable
thiiranes. Then this procedure should be transferred to the
preparation of seleniranes und thiirenes. The expected highly
unstable seleniranes should be stabilized by the use of the
extreme sterical demanding alkene bis(adamantylidene) Ad=Ad
(1). The latter has enabled us already in the isolation of the
extreme unstable telluriranium salts.[5]
Introduction
Thiiranium[1] and thiirenium salts[2] are long known. In recent
years we have prepared selenirenium und tellurirenium salts[3,4]
and also the saturated seleniranium and telluriranium salts[5], see
also ref. [6]. These are key intermediates in electrophilic addition
reactions of organochalcogen cation equivalents [RE+ X–] to
alkynes and alkenes.[7-14]
Thiirenes should be stabilized by the sterically demanding
alkynes tBuCCtBu (2) and diadamantyl acetylene AdCCAd
(3).[3,4] The interesting question has been whether F– or OH– would
indeed attack at the protecting group, or if the reaction would
occur at the C or chalcogen ring atoms.
However the knowledge about uncharged C2-chalcogen three-
membered rings is limited almost to thiiranes.[15] Seleniranes[16]
have been described as unstable intermediates[17] and also in
substance,[18] but no structural proof for this class of compounds
exists, however. The postulated instability, meaning the easy
decomposition into alkene and elemental selenium, calls into
question their existence, see here the discussion about
seleniranes and telluriranes by Braunschweig.[19] Unexpectedly,
results by Sardar et al. are surprising,[18d] who claim to have made
seleniranes at high temperatures, which have very unusual 77Se
NMR shifts in the region of 600 – 700 ppm. So far, telluriranes
have not been mentioned in the literature.The search for thiirenes
lasts already long. These would be of great theoretical interest as
antiaromatic cyclic 4-electron compounds.[20,15b] This would
explain their extreme instability. The calculated NICS (1) value of
–2.2 ppm does not allow a clear statement on the question of
antiaromaticity. With NBO a hybridization of 3s1.8 3p4.16 is
calculated for the S atom in Thiirene (see Table S1 in the
F–
B–
E+
– Me3SiF, – C2H4
E
– HB, – CH2=CH–CN
E+
H
?
B–
E = S, Se
F–
SiMe3
CN
F–
S+
– Me3SiF, – C2H4
S
?
F–
SiMe3
Scheme 1. Synthetic concept for thiiranes, seleniranes and thiirenes.
Results and Discussion
We used RE+ electrophiles for the preparation of the three-
membered ring salts that we have developed earlier: Either by
two-electron oxidation of the disulfides and diselenides with XeF2
in combination with fluoride ion acceptors like Tf2NSiMe3,
[a]
Dr. Helmut Poleschner, Prof. Dr. Konrad Seppelt
Institut für Chemie und Biochemie, Anorganische Chemie
Freie Universität Berlin,
Fabeckstr. 34-36, 14195 Berlin (Deutschland),
E-mail: hpol@zedat.fu-berlin.de
BF3·OEt2 or Me3Si+ CHB11Cl11
,
– [4,5] or by chlorination with SO2Cl2.
–
The reagent [RE+ SbCl6 ] is generated subsequently by reaction
with SbCl5.[3,5]
Supporting information for this article is given via a link at the end of
the document.
1
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Thiiranium Salts
XeF2/BF3·OEt2, and the chlorination with SO2Cl2, reaction with
SbCl5 and addition of 1. For this sake the synthesis of the
cyanoethyldiselenide (15) had to be improved, since according to
ref. [24a] only mixtures of di and triselenide are obtained. The at
first prepared cyanoethyl selenocyanate[27] (18) reacts with
LiEt3BH, and oxidation with O2 selectively gives the diselenide 15
(see Scheme 4).[28] The instability of the seleniranium salts with
the Me3SiCH2CH2 group contrasts with the much higher stability
of the non-functionalized seleniranium salts.[5] Therefore we tried
to prepare the salts carrying the tBuMe2SiCH2CH2 group, since
we assumed that
The disulfide (Me3SiCH2CH2S)2 (4) is oxidized with
XeF2/Tf2NSiMe3 and reacted in presence of the alkene 1, yielding
the thiiranium salt [Ad2SCH2CH2SiMe3]+ Tf2N– (5). The Me3Si
group in 4 is not attacked by XeF2. By chlorination of 4 with SO2Cl2
and subsequent reaction with SbCl5 and 1, the chloroethyl
–
thiiranium salt [Ad2SCH2CH2Cl]+ SbCl6 (6) is formed, which is
identified by ESI-MS. Here the Me3Si group is cleaved off and
substituted by Cl. Use of the more stable tBuMe2Si group in the
disulfide (tBuMe2SiCH2CH2S)2 (7) the method with SO2Cl2/SbCl5
and 1 produces the salt [Ad2SCH2CH2SiMe2tBu]+ SbCl6– (8). With
7, XeF2/Tf2NSiMe3, and 1 the salt 9 is formed.
The cyanoethyl thiiranium salts 11, 12 are reacted with
(NCCH2CH2S)2 (10) and 1, either with XeF2/Tf2NSiMe3, or with
SO2Cl2/SbCl5 (see Scheme 2).
The new thiiranium salts show in the ESI mass spectra the
expected mol peaks for the cations and anions. The 13C NMR
spectra show the characteristic signal of the three-membered ring
C-atoms at 96-99 ppm, as compared to 67 – 105 ppm in ref. [25].
–
The less soluble SbCl6 salts crystallize well, and crystal
–
structures
of
[Ad2SCH2CH2SiMe2tBu]+ SbCl6
(8)
and
[Ad2SCH2CH2CN]+ SbCl6– (12) had been obtained (see Figures 1
and 2). These new thiiranium ions have C–C bond lengths of
150.0 – 150.6 pm within the three-membered ring, C–S bond
lengths of 189.4 – 191.8 pm, and C-S-C angles of 46.4°. The C–
S bond to the substituent at the S atom are a little shorter (182.3
– 183.8 pm) than the C–S bonds within the ring. Known thiiranium
salts have quite similar bond parameters.[25,26]
S)2
4
/
(Me3Si
XeF2 / Tf2NSiMe3
S+
S+
S+
S+
Tf2N–
5
6
Figure 1. Molecular structure of [Ad2SCH2CH2SiMe2tBu]+ SbCl6–·EtCN (8),[41]
50 % probability ellipsoids. The anion and solvent have been omitted for clarity.
Selected bond parameters [pm,°]: C1–C11 150.6(6), S–C1 190.1(5), S–C11
191.6(5), S–C21 183.8(5), C21–C22 153.2(7), Si–C22 189.8(5), C1-S-C11
46.47(19).
SiMe3
S)2
4
/
(Me3Si
SO2Cl2 / SbCl5
–
SbCl6
Cl
S)2
7
/
1
(tBuMe2Si
SO2Cl2 / SbCl5
SbCl6–; Tf2N–
or
7
/ XeF2 / Tf2NSiMe3
8 9
;
SiMe2tBu
S)2 10
XeF2 / Tf2NSiMe3
or 10 / SO2Cl2 / SbCl5
/
(NC
–
Tf2N–; SbCl6
11 12
;
CN
Figure 2. Molecular structure of [Ad2SCH2CH2CN]+ SbCl6–·CH2Cl2 (12),[41] 50 %
probability ellipsoids. The anion and solvent have been omitted for clarity.
Selected bond parameters [pm,°]: C1–C9 150.0(4), S–C1 191.8(3), S–C9
189.4(3), S–C23 182.3(3), C22–C23 153.1(5), C21–C22 146.5(1), N–C21
113.9(5), C1-S-C9 46.35(12).
Scheme 2. Synthesis of the thiiranium salts with the Me3SiCH2CH2,
tBuMe2SiCH2CH2, and NCCH2CH2 groups.
Seleniranium Salts
these would be more stable. The corresponding diselenide
(tBuMe2SiCH2CH2Se)2 (22) is synthesized from the vinylsilane
(19). Hydroboration with 9-borabicyclononane (9-BBN) and
oxidation of the borane with H2O2 gives the silylethanol (20), see
also ref. [29], followed by bromination with PPh3/CBr4 affording
tBuMe2SiCH2CH2Br (21).[23c] This, however, reacts with Li2Se2 to
diselenide that is contaminated with considerable amounts of
triselenide. The product mixture is reduced in liquid NH3/THF with
Na and afterwards reoxidized with O2 to the diselenide 22 (see
Scheme 4). The disulfide (tBuMe2SiCH2CH2S)2 (7) is prepared
similarly with Li2S2.
These methods of synthesis can only applied in part to the Se
compounds. The diselenide (Me3SiCH2CH2Se)2 (13) reacts with
XeF2/Tf2NSiMe3 and 1 forming the seleniranium salt 14, which
decomposes already at room temperature under formation of
elemental selenium (see Scheme 3). However, 13C and 77Se NMR
spectra can be obtained directly from the reacting solution
at -40°C, which are in accordance with the structure of 14.
Specially the 13C signal of the ring-C atom at 110 ppm and the
77Se signal of the highly shielded Se atom at 35 ppm are typical
values.[5] With the diselenide (NCCH2CH2Se)2 (15) both synthetic
routes are successful, namely with the oxidation by
2
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(tBuMe2SiCH2CH2Se)2 (22) reacts with 1 and XeF2/Tf2NSiMe3 or
XeF2/Me3Si+ CHB11Cl11–, and here also with SO2Cl2/SbCl5 to the
seleniranium salts 23–25 (see Schema 5). The salts carrying the
tBuMe2SiCH2CH2 group decompose slowly in solution at room
temperature, e.g. during NMR measurements. They can be
isolated as solid compounds and are stable for prolonged time at
–20°C. The 13C NMR shows signals that are typical for the three-
membered ring at 110 ppm, and 77Se signals at high field 24 – 39
ppm. These values are very close to those of the [Ad2SeEt]+ ion.[5]
ESI mass spectra have correct molecular peaks for cations and
anions.
place even of the tBuMe2Si group. The structurale parameters
within the three-membered rings in these seleniranium salts (C–
C bond lengths of 147.9 – 148.9 pm, C–Se bond lengths of 205.5
– 209.7 pm, C–Se bond lengths to the groups at the Se atoms of
196.5 – 200.2 pm, and the C-Se-C bond angle of 41.8 – 42.4°)
are almost identical to those of our [Ad2SeEt]+ salt,[5] see also ref.
[6a].
Dealkylation of the Thiiranium Salts – Thiiranes.
We began the attempts to cleave off the protecting groups with
the thiiranium salts. Salt 5 reacts surprisingly selective with Bu4NF
in THF and under cleavage of the Me3SiCH2CH2 group at –40o.
The thiirane Ad2S 27 was isolated. Then we tried to combine the
preparation of the thiiranium salt and its dealkylation in a one-pot
procedure. Alkene 1 reacts with disulfide 4 and XeF2/BF3·OEt2
and the formed thiiranium salt is reacted with the Bu4NF solution
without isolating it. The expected thiirane 27 is obtained in
quantitative yield. Its molecular structure has been determined by
its crystal structure determination (see Figure 5).
Se)2 13
/
(Me3Si
XeF2 / Tf2NSiMe3
Se+
Tf2N– 14
SiMe3
unstable, decomposition at r. t.
1
Se)2 15
/
(NC
XeF2 / BF3·OEt2
Se+
BF4–; SbCl6
–
or 15 / SO2Cl2 / SbCl5
16; 17
CN
Scheme 3. Synthesis of the seleniranium salts carrying the Me3SiCH2CH2 and
NCCH2CH2 groups.
1. LiEt3BH
KSeCN
2. O2
Br
SeCN
Se)2
NC
NC
(NC
18
15
1. 9-BBN
2. H2O / NaOH
Ph3P / CBr4
OH
tBuMe2Si
tBuMe2Si
tBuMe2Si
19
21
20
Li2Se2
Br
Se)2
+
(tBuMe2Si
(tBuMe2Si
Se)2Se
1. Na / liq. NH3 / THF
2. O2
Se)2
Figure 3. Molecular structure of [Ad2SeCH2CH2SiMe2tBu]+ SbCl6–·CH2Cl2
(25),[41] 50 % probability ellipsoids. The anion and solvent have been omitted for
clarity. Selected bond parameters [pm,°]: C1–C2 147.9(4), Se–C1 206.0(3), Se–
C2 207.3(3), Se–C21 197.3(3), C21–C22 152.8(4), Si–C22 189.6(3), C1-Se-C2
41.94(11).
(tBuMe2Si
22
Scheme 4. Synthesis of the diselenides 15 und 22.
Se)2 22
/
(tBuMe2Si
XeF2 / Tf2NSiMe3–;
Me3Si+ CHB11Cl11
Se+
–
Tf2N–, CHB11Cl11
;
or 22 / SO2Cl2 / SbCl5
–
1
SbCl6
23
25
, 24;
SiMe2 Bu
t
Se+
SbCl6
–
26
Cl
Scheme 5. Synthesis of the seleniranium salts carrying the tBuMe2SiCH2CH2
group.
Crystal structure determinations of the new seleniranium salts
–
[Ad2SeCH2CH2SiMe2tBu]+ SbCl6 (25) and [Ad2SeCH2CH2CN]+
Figure 4. Molecular structure of [Ad2SeCH2CH2CN]+ SbCl6–·CH2Cl2 (17),[41]
50 % probability ellipsoids. The anion and solvent have been omitted for clarity.
Selected bond parameters [pm,°]: C1–C19 148.9(9), Se–C1 209.7(5), Se–C19
207.7(5), Se–C21 200.2(6), C21–C22 149.1(9), C22–C23 146.7(10), N–C23
111.1(9), C1-Se-C19 41.8(2).
SbCl6– (17) prove the structures (see Figures 3 und 4). By reacting
of 22 with SO2Cl2/SbCl5 and
1
the side product
–
[Ad2SeCH2CH2Cl]+ SbCl6 (26) is isolated and characterized by
ESI-MS und a crystal structure determination (see Figure S1 in
the supporting information). Here also a partial cleavage takes
3
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Cis-cyclooctene (28) as a simple sterically unstrained alkene is
reacted in a one-pot procedure with 4 and XeF2/BF3·OEt2, and
subsequently with Bu4NF. The preparation of the thiirane 30 was
also successful, as proven by the cis-structure in the crystal. 30
exists in the solid state in two different forms in a 1:1 ratio, and
these are mirror images of each other. Figure 6 shows both
molecules, the S atoms pointing to the viewer. In the crystalline
state they are oriented in a different manner.
salts (189.4 – 191.8 pm). In 27 the C-S-C angle is consequently
a little larger (48.1°) as compared to 8 and 12 (46.4 – 46.5°).
Bu4NF, THF
S+
70%
Tf2N–
5
SiMe3
S)2
4
/
Figure 5. Molecular structure of Thiirane 27,[41] 50 % probability ellipsoids.
Selected bond parameters [pm,°]: C1–C11 150.73(16), S–C1 184.92(12), S–
C11 185.11(12), C1-S-C11 48.08(5).
1. (Me3Si
XeF2 / BF3·OEt2
S
27
2. Bu4NF, THF
99%
1
1.
4
/ XeF2 / BF3·OEt2
2. Bu4NF, THF
67%
28
S
1.
4
/ XeF2 / BF3·OEt2
2. Bu4NF, THF
30
45%
29
Figure 6. Molecular structure of Thiirane 30,[41] 50 % probability ellipsoids.
Selected bond parameters [pm,°]: C11–C18 147.2(6), S1–C11 183.4(5), S1–
C18 183.1(5), C11-S1-C18 47.38(18), C12-C11-C18-C17 –1.902(720); C1–C8
148.9(6), S2–C1 184.0(5), S2–C8 184.2(5), C1-S2-C8 47.71(19), C2-C1-C8-C7
0.039(743).
Bu4NF, THF
S+
+
Tf2N–
1
9
S)2
7
(tBuMe2Si
SiMe2tBu
Attepts to Dealkylation of Seleniranium Salts – Selenirane?
S
only traces
For the sake of detection and preparation of a selenirane
reactions were undertaken to cleave off the Me3SiCH2CH2 group
from seleniranium salts. Learning from the results with the
thiiranium salts we have used for these reactions solely
+
CsOH, H2O / THF
S+
S
27
Tf2N–
11
CsOH, MeOH / THF
compounds
with
this
protecting
group.
The
[Ad2SeCH2CH2SiMe3]+ salts turned out to be unstable, so these
reactions were done in a one-pot procedure, meaning the
preparation of the seleniranium salts is followed by immediate
reaction with Bu4NF. Because of the expected instability of the
target compound, the preparation of the seleniranium salt and the
dealkylation were done at –40°C.
CN
1
Scheme 6. Cleavage of the protecting groups from the thiiranium salts.
If trans-cyclooctene 29 is subjected to the same protocol, the
same cis-thiirane 30 is formed as with the cis-alkene; the products
have identical 13C NMR spectra. Addition of the Me3SiCH2CH2S+-
electrophile to the trans-alkene results in a configuration inversion
of the strained 8-membered ring system. On cis-trans
isomerizations of thiiranium ions via ring-opened carbocations
see refs. [1h,i]. There are incorrect data in ref. [30]: A postulated
trans-9-thiabicyclo[6.1.0]nonane has exactly the same 13C NMR
data as our cis-compound 30. For other 13C NMR data of the
trans-isomer see ref. [31].
The reaction of Bu4NF with the thiiranium salt 9 carrying the
tBuMe2SiCH2CH2 group does not give the thiirane 27, but the
cleavage of the tBuMe2SiCH2CH2S group is observed. The three-
membered ring is attacked instead: the 13C NMR spectrum shows
only the alkene 1 and the disulfide (tBuMe2SiCH2CH2S)2 (7), and
only traces of the thiirane 27. The tBuMe2SiCH2CH2 group is
obviously too stable as protecting group for our purposes (see
Scheme 6).
We calculated by DFT the 13C and 77Se NMR shifts of the
selenirane ring, together with those of the thiiranium and
seleniranium ions and the thiirane 27. Considering the small
differences between calculated and experimental data the
selenirane should have a 13C signal at about 85 ppm and a 77Se
resonance at about 70 ppm (see Scheme 7).
111.0
79.0
S
S+
Me
exp. (13C ring) 92.3
71.6
125.4
92.1
Se
Se+
–47
42.2
Me
The NCCH2CH2 group in the thiiranium salts 11 and 12 is also no
useful protecting group for the liberation of the thiirane 27. 11 and
12 react after 3 h at 0°C with CsOH in H2O/THF or MeOH/THF to
mixtures of 1 and the thiirane 27 in the ratios of 1:3 to 1:1,
according to the 13C NMR spectra. Besides the dealkylation a lot
cleavage takes place of the three-membered ring.
exp. (13C ring) 108.0
exp. (77Se)
–19.7
Scheme 7. By GIAO-B3PW91/cc-pVTZ//B3PW91/6-311+G(d,p) theory
calculated 13C and 77Se NMR chemical shifts [ppm] (=ref - comp), relative to
TMS and Me2Se, including experimental data.
The structures of the thiirane 27 and thiiranium salts 8 and 12
have C–C bonds of similar lengths (150.0 – 150.7 pm). In the
thiirane the C–S bonds are a little shorter (185 pm) than in the
At first we prepared the seleniranium salt 14 by reacting 1, the
diselenide 13, and XeF2/Tf2NSiMe3 at –40°C. A solution of Bu4NF
in THF is added at –78°C, followed by stirring at –40°. The 13C
4
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NMR measurement of the reaction solution at –78oC shows only
the compounds 1 and 13, while 77Se spectra show the presence
of 13 and an organoselenium trifluoride, most likely
Me3SiCH2CH2SeF3 by a new signal at 1187 ppm (NMR spectra of
RSeF3 see refs. [32,33]). There is no indication for the selenirane
33. The F– ion possibly attacks the selenium atom of the
seleniranium ring, which is cleaved to the alkene 1 and the
selenium monofluoride Me3SiCH2CH2SeF (31). The latter is
unstable and disproportionates according to 3RSeF  R2Se2 +
Summing up: The method of cleaving off the protecting groups
works only with thiiranium salts, where the Me3SiCH2CH2 group is
S)2
4
/
tBu
tBu
(Me3Si
XeF2 / BF3·OEt2
tBu
tBu
S+
S+
S+
–
BF4
2
3
3
34
SiMe3
RSeF3 in
a
known manner[32-34] to the diselenide
S)2
4
/
(Me3Si
(Me3SiCH2CH2Se)2 (13) and the trifluoride Me3SiCH2CH2SeF3
(32) (see Scheme 8).
We also attempted a reaction of 1, 13, XeF2/BF3·OEt2 and Bu4NF,
XeF2 / Tf2NSiMe3
Tf2N–
35
with the same results.
SiMe3
The reaction of the seleniranium salt 16 with CsOH in THF/H2O
at –40° C cleaves the three-membered ring selectively to the
olefin 1 and the diselenide 15, a selenirane is not observed (see
Scheme 8).
S)2
7 /
(tBuMe2Si
XeF2 / Tf2NSiMe3
Tf2N–
36
SiMe2tBu
Se)2 13
/
(Me3Si
XeF2 / Tf2NSiMe3
Se+
Tf2N–
14
SiMe3
Scheme 9. Synthesis of thiirenium salts.
1
Bu4NF
SeF
+
Me3Si
1
31
Se)2 13
SeF3 32
(Me3Si
Me3Si
Se
no indication of selenirane
+
33
CsOH
1
Se+
BF4
+
–
Se)2 15
16
(NC
CN
Figure 7. Molecular structure of [Ad2C2SCH2CH2SiMe2tBu]+ Tf2N– (36),[41] 30 %
probability ellipsoids. The anion has been omitted for clarity. Selected bond
parameters [pm,°]: C21–C22 128.9(11), S–C21 185.4(11), S–C22 181.0(9), S–
C23 182.6(6), C23–C24 152.6(7), Si–C24 188.7(6), C21-S-C22 41.2(3).
Scheme 8. Attempts for prepration of a selenirane.
Thiirenium Salts
The thiirenium salt 34 is prepared by oxidation of the disulfide 4
with XeF2/BF3·OEt2 in presence of di-tert-butylacetylene (2). The
synthesis succeeds also for the thiirenium salts 35 and 36 by
reaction of the diadamantylacetylene (3) with
4
and
Bu4NF, THF
S+
XeF2/Tf2NSiMe3 or the disulfide 7 and XeF2/Tf2NSiMe3 (see
Scheme 9). These compounds crystallize badly and often are
obtained as oils. However single crystals have been obtained of
the compound 36. Figure 7 shows the crystal structure.
The 13C NMR signals of the ring-C atoms of these thiirenium ions
are in the same region (113 – 115 ppm) as in the unsubstituted
thiirenium salts.[1f,4,35]
Tf2N–
3
35
SiMe3
S
37
no indication of Thiirene
The structure of 36 has a C=C bond length of 128.9 pm within the
three-membered ring, die S–C bonds are 185.4 und 181.0 pm
long, to the tBuMe2SiCH2CH2 group 182.6 pm. The C-S-C angle
is 41.2°. This three-membered ring is quite similar to those in the
non-substituted alkylthiirenium salts.[26,36,5]
Schema 10. Attempts for syntheses a thiirene.
leaving and a thiirane is liberated. In thiiranium salts with the
tBuMe2SiCH2CH2 or NCCH2CH2 groups, in seleniranium salts
with the Me3SiCH2CH2 and NCCH2CH2 groups, and in thiirenium
salts with the Me3SiCH2CH2 group the attack by F– or OH– takes
place at the heteroatom of the three-membered ring. In these
cases, the RS+ or RSe+ part is cleaved off, and an alkene or
alkyne is formed. In sterically unprotected thiiranium and
seleniranium ions the attack by nucleophiles happens mostly at
the C atom of the three-membered rings,[6b,8-14] very much alike to
thiirenium ions.[2d] This is also the case during the fluorothiolation
and fluoroselenation of alkenes and the fluoroselenation of
alkynes.[37,38,7] But there are examples known where the RS+
group is transferred from thiirenium ions to transition metal
complexes or C nucleophiles.[39,2d] Finally we want to point to the
Attempts towards Dealkylation of Thiirenium Salts –
Thiirene?
We tried to cleave off the Me3SiCH2CH2 group from the thiirenium
salt 35 by reaction with Bu4F at –60°C. 13C NMR shows that,
analogously to the seleniranium salts, a selective attack by the F–
Ions occurs at the sulfur atom. Alkyne 3 is liberated, and there is
no indication for the formation of a thiirene 37. No cleavage of the
Me3SiCH2CH2 group is observed (see Scheme 10).
5
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transition of RS+ and RSe+ groups in thiiranium, seleniranium or
thiirenium ions to alkenes and alkynes, where the C–C-multiple
bond preferably interacts with the heteroatom of the three-
membered ring.[1g,6,2d,40]
OH– at the chalcogen atom of the three-membered ring, under
cleavage of the RS+ or RSe+ groups and liberation of the alkene
and alkynes. The synthesis of a selenirane and a thiirene
remains an open challenge.
We tried to understand the different reactivity of the compounds
carrying the Me3SiCH2CH2 groups by calculating HOMO and
LUMO of the thiiranium (A), seleniranium (B), and thiirenium ions
(C), as shown in Figure 8. In all three ions the HOMO is spread
over the entire molecule including the Me3SiCH2CH2 group. The
LUMO, however, is localized at the three-membered ring,
especially at the heteroatom. This is also the case in the unsubsti-
tuted ions [Ad2EEt]+ (D, E) and those with the cyanoethyl group
[Ad2ECH2CH2CN]+ (F, G) (E = S, Se) (see Figure S2 in the
supporting information). In an orbital controlled attack by the F–
ions there should be an interaction with the LUMO of the three-
membered rings. Therefor the cleavage of the RSe+ group from
B or the cleavage of the RS+ group from C by the F– ion is more
likely than the attack at the Me3Si group. The lower lying LUMO
energy in the ions B and C relative to A should favor the attack at
the three-membered rings. Since the NBO calculated positive
charge on the S atom in thiiranium ion A is lower than at the
heteroatoms in B and C, an attack by the F– ions at the Si atom
in A in competition to the S atom is comprehensible.
Experimental Section
General
Dried solvents and argon as protection gas were used. 11B 13C, 19F, 29Si
and 77Se NMR spectra were recorded on a JEOL ECZ 400R or on a JEOL
ECS 400 spectrometer (128.25, 100.51, 376.13, 79 and 76.24 MHz,
respectively). Chemical shifts δ are reported in ppm relative to BF3·OEt2
(
11B), Me4Si (13C, 29Si), CFCl3 (19F) and Me2Se (77Se).
For ESI-TOF mass spectra the samples were measured from CH3CN,
CH3CN/CH2Cl2, CH3OH or CH3CN/CH3OH solutions on an Agilent 6210
ESI-TOF, Agilent Technologies, Santa Clara, CA, USA. Solvent flow rate
was adjusted to 4 μL/min, spray voltage set to 4 kV. Drying gas flow rate
was set to 15 psi (1 bar) (ESI-TOF=electrospray ionization - time of flight).
Non-ionic compounds were analyzed with a HR-EI-MS (Autospec Premier,
Waters Co., Milford, MA, USA) using 80 eV electron energy.
Quantum chemical calculations
Calculations were performed with Gaussian 16[42] on high-performance
computer system SOROBAN at Zedat, Freie Universität Berlin,
https://www.zedat.fu-berlin.de/HPC/Soroban.
The Olefin Ad=Ad (1),[43] trans-cyclooctene (29),[44] the alkynes tBuCCtBu
(2) and AdCCAd (3),[45] the Si compounds Tf2NSiMe3
and
[46]
Me3Si+ CHB11Cl11[4] were prepared according to known procedures.
1: 13C NMR (CDCl3) δ = 133.17 (C=C), 39.64 (8xCH2), 37.37 (2xCH2),
31.93 (4xCH), 28.60 (4xCH).
2: 13C NMR (CDCl3) δ = 87.08 (CC), 31.58 (CMe3), 27.14 (CMe3).
3: 13C NMR (CDCl3) δ = 87.59 (CC), 43.55 (6xCH2), 36.47 (6xCH2), 29.19
(Cq), 28.19 (6xCH).
Syntheses of (Me3SiCH2CH2S)2 (4) and (Me3SiCH2CH2Se)2 (13)[23c]
Li2S2 and Li2Se2 are prepared by reacting 60 mmol Li (420 mg) with 60
mmol S (1.92 g) or 60 mmol Se (4.47 g ) in 150 mL liq. NH3. After
evaporation of the NH3 50 mL THF is added. Under stirring 60 mmol
Me3SiCH2CH2Br is added dropwise followed by stirring at room
temperature for 12 h. Addition of water and extraction with CH2Cl2 is
followed by vacuum distillation.
4: Yield 6.2 g (78%), b.p. 86°C/0.19 mbar. EI-MS: [266, M+] (C10H26S2Si2).
13C NMR (CDCl3) δ = 34.77 (CH2S), 17.23 (1JSi,C = 47.9 Hz, CH2Si), –1.60
(1JSi,C = 51.0 Hz, CH3Si).
13: Yield 7.61
g
(70%), b.p. 100°C/0.08 mbar. EI-MS: [362, M+]
(C10H26Se2Si2). 77Se NMR (CDCl3) δ = 355.8. 13C NMR (CDCl3) δ = 24.92
(1JSe,C = 69.8 Hz, CH2Se), 19.55 (1JSi,C = 47.2 Hz, CH2Si), –1.63 (1JSi,C
=
50.9 Hz, CH3Si).
Synthesis of (NCCH2CH2Se)2 (15)
NCCH2CH2SeCN (18) is prepared from 0.1 mol NCCH2CH2Br (13.4 g) and
0.1 mol KSeCN (14.4 g) in 50 mL DMF according to ref. [27].
To 60 mmol 18 (9.54 g) in 100 mL THF are added dropwise at–78°C 65
mmol LiEt3BH (65 mL 1 M in THF),[27,28] followed by 1 h stirring at this
temperature. After warming to room temperature and further stirring for 1
h O2 is bubbled through the reaction solution for 30 min. THF is pumped
off in vacuum. The remainder is dissolved in H2O (300 mL) and extracted
with CH2Cl2. The product is purified by column chromatography on silica
gel with mixtures of CH2Cl2/hexane, 300 mL 30:70, 450 mL 40:60, 150 mL
50:50, 150 mL 60:40, 150 mL 70:30, 150 mL 80:20.
Figure 8. HOMO and LUMO of the ions A – C, orbital energies [Hartrees] and
NBO charges, calculated on B3PW91/6-311+G(d,p) level of theory.
18: Yield 13.1
g
(82%), b.p. 133°C/0.09 mbar. EI-MS: [160, M+]
(C4H4N2Se). 77Se NMR (CDCl3) δ = 244.2. 13C NMR (CDCl3) δ = 117.97
(CN), 101.46 (1JSe,C = 237.5 Hz, SeCN), 23.24 (1JSe,C = 59.4 Hz, CH2Se),
20.21 (CH2CN).
Conclusions
Thiiranium salts [Ad2SCH2CH2SiMe3]+ X– are dealkylated by the
F– ion giving the thiiran Ad2S. Thiiranium salts with the
tBuMe2SiCH2CH2 or NCCH2CH2 group, seleniranium salts
[Ad2SeCH2CH2SiMe3]+ X– and [Ad2SeCH2CH2CN]+ X– as well as
thiirenium salts [Ad2C2SCH2CH2SiMe3]+ X– are attacked by F– or
15: Yield 5.2 g (49%). EI-MS: [268, M+] (C6H8N2Se2). 77Se NMR (CDCl3) δ
= 326.5. 13C NMR (CDCl3) δ = 119.14 (CN), 23.00 (1JSe,C = 81.0 Hz,
CH2Se), 19.79 (CH2CN).
Syntheses of (tBuMe2SiCH2CH2S)2 (7) and (tBuMe2SiCH2CH2Se)2 (22)
6
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Under argon 0.1 mol vinylsilane 19 (14.2 g) are added dropwise to a stirred
solution of 0.114 mol 9-BBN (230 mL 0.5 M in THF), followed by refluxing
for 2 h, see ref. [29]. After cooling to room temperature H2O (100 mL) is
carefully added, then NaOH (14 g in 120 mL H2O) and 120 mL 30% H2O2
are added, followed by refluxing for 1.5 h. After extraction with Et2O very
pure silylethanol 20 is obtained.
Into a stirred solution of 75 mmol 20 (12 g) and 82.5 mmol CBr4 (27.4 g) in
80 mL CH2Cl2 82.5 mmol Ph3P (21.6 g) are added within 5 min at 0°C,
followed by 2 h stirring at 0°C. After evaporation of the THF the product is
dissolved in pentane, filtered through silica gel, and the bromide 21 is
vacuum distilled.
26.50 (2xCH), 26.48 (CMe3), 25.91 (2xCH), 16.43 (CMe3), 12.37 (CH2Si),
–7.15 (MeSi). 29Si NMR (CD2Cl2) δ = 10.05.
[Ad2SCH2CH2CN]+ Tf2N– (11)
Yield 580 mg (46%). ESI-MS (CH3CN): [354.2268]+ (C23H32NS+),
[279.9181]– (C2F6NO4S2–). 13C NMR (CD2Cl2)) δ = 119.71 (q, 1JF,C = 321.3
Hz, CF3), 115.99 (CN), 99.00 (ring C), 38.94 (2xCH2), 38.54 (2xCH2),
37.85 (2xCH2), 36.49 (2xCH2), 35.95 (2xCH2), 33.93 (2xCH), 30.19 (2xCH),
26.40 (2xCH), 26.30 (2xCH), 25.18 (CH2S), 16.23 (CH2CN)
.
Thiiranium Salts 8, 12, according to method B
[Ad2SCH2CH2SiMe2tBu]+ SbCl6– (8)
Yield 1.46
g
(94%). ESI-MS (CH3OH): [443.3177]+ (C28H47SSi+),
7 und 22 are synthesized by producing Li2S2 or Li2Se2 from 30 mmol Li
(208 mg) and 30 mmol S (962 mg) or Se (2.37 g) in 150 mL liq. NH3 (2.37
g). Li2S2 or Li2Se2 are reacted to 4 and 13 similar to the described way
above with 30 mmol tBuMe2SiCH2CH2Br 21 (6.7 g). After aqueous workup
[334.7208]– (SbCl6–). 13C NMR (CD2Cl2)) δ = 96.75 (ring C), 38.91 (2xCH2),
38.42 (2xCH2), 38.38 (2xCH2), 37.27 (2xCH2), 36.15 (2xCH2), 33.78
(2xCH), 30.63 (2xCH), 28.12 (CH2S), 26.62 (2xCH), 26.59 (2xCH), 26.15
(CMe3), 16.62 (CMe3), 12.70 (CH2Si), –6.63 (MeSi).
and extraction with Et2O the disulfide
chromatography on silica gel with hexane.
7
is purified by column
Single crystals of 8 are prepared by slow cooling of a solution in EtCN from
room temperature to –80°C.
The raw product of the selenium compound is freed from triselenide by
dissolving in 100 mL liq. NH3 and 50 mL dry THF. 60 mmol Na (1.4 g) is
added and the blue solution is stirred for 1 h. After evaporation of the NH3
and addition of 100 mL H2O O2 is bubbled through the solution for 1 h.
Purification is done by extraction with Et2O and column chromatography in
hexane.
[Ad2SCH2CH2CN]+ SbCl6– (12)
Yield 1.13
g
(82%). ESI-MS (CH3CN): [354.2286]+ (C23H32NS+),
[334.7125]– (SbCl6–).
Single crystals of 12 are obtained by slow addition of pentane into a
solution CH2Cl2 at –20°C until beginning clouding sets in, and slow cooling
from room temperature to –80° C.
20: Yield 16 g (100 %). 13C NMR (CDCl3) δ = 59.42 (CH2OH), 26.35 (CMe3),
17.80 (1JSi,C = 46.0 Hz, CH2Si) , 16.27 (CMe3), –6.09 (1JSi,C = 49.8 Hz,
CH3Si). 29Si NMR (CDCl3) δ = 6.31.
Seleniranium Salts 14, 16, 23, 24 according to method A
[Ad2SeCH2CH2SiMe3]+ Tf2N– (14): Low temperature NMR measurement at
–40°C. 77Se NMR (CD2Cl2) δ = 35.3. 13C NMR (CD2Cl2) δ = 119.08 (q, 1JF,C
= 321.0 Hz, CF3), 109.66 (ring C), 39.38 (2xCH2), 39.33 (2xCH2), 39.20
(2xCH2), 38.19 (2xCH2), 37.05 (2xCH2), 33.56 (2xCH), 31.14 (2xCH),
27.55 (CH2Se), 26.63 (4xCH), 15.47 (CH2Si), –2.72 (MeSi).
21: Yield 11.6 g (69%), b.p. 49-51°C/0.2 mbar. 13C NMR (CDCl3) δ = 32.33
(CH2Br), 26.42 (CMe3), 20.41 (1JSi,C = 43.0 Hz, CH2Si), 16.60 (CMe3), –
6.26 (1JSi,C = 50.2 Hz, CH3Si). 29Si NMR (CDCl3) δ = 8.34.
7: Yield 4,54 g (86%). EI-MS: [350.1959, M+] (C16H38S2Si2). 13C NMR
(CDCl3) δ = 35.28 (CH2S), 26.61 (CMe3), 16.69 (CMe3), 13.37 (1JSi,C = 46.4
Hz, CH2Si), –6.16 (1JSi,C = 50.0 Hz, CH3Si). 29Si NMR (CDCl3) δ = 8.61.
[Ad2SeCH2CH2CN]+ BF4– (16)
Yield 0.8g (82%). ESI-MS (CH3CN/CH2Cl2): [402.1845]+ (C23H32NSe+),
[87.0002]– (BF4–). 77Se NMR (CD2Cl2) δ = 24.1. 13C NMR (CD2Cl2) δ =
117.22 (CN), 111.87 (ring C), 39.97 (2xCH2), 39.71 (2xCH2), 39.48
(2xCH2), 38.09 (2xCH2), 36.66 (2xCH2), 34.28 (2xCH), 31.29 (2xCH),
26.96 (2xCH), 26.87 (2xCH), 24.15 (CH2Se), 15.78 (CH2CN). 19F NMR
(CD2Cl2)) δ = –151.04.
22: Yield 4,2 g (63%). EI-MS: [446, M+] (C16H38Se2Si2). 77Se NMR (CDCl3)
δ = 361.5. 13C NMR (CDCl3) δ = 26.69 (CMe3), 25.37 (1JSe,C = 69.9 Hz,
CH2Se), 16.77 (CMe3), 15.74 (1JSi,C = 45.7 Hz, CH2Si), –6.16 (1JSi,C = 49.9
Hz, CH3Si). 29Si NMR (CDCl3) δ = 8.70.
[Ad2SeCH2CH2SiMe2tBu]+ Tf2N– (23)
Syntheses of the Thiiranium und Seleniranium Salts
Yield 0.78 g
(51%). ESI-MS (CH3CN): [491.2611]+ (C28H47SeSi+),
[279.9217]– (C2F6NO4S2–). 77Se NMR (CD2Cl2) δ = 44.8.
Method A: 1/R2S2 or R2Se2/XeF2/fluoride ion acceptor
15 mL dry CH2Cl2 are condensed on Ad=Ad 1 (2 mmol, 537 mg) and the
disulfide 4 (1 mmol, 267 mg), 7 (1 mmol, 351 mg), 10 (1 mmol, 172 mg) or
diselenide 13 (1 mmol, 360 mg), 15 (1 mmol, 266 mg), 22 (1 mmol, 445
mg) at –196°C. XeF2 (1 mmol, 169 mg), and Tf2NSiMe3 (2 mmol, 707 mg),
BF3·OEt2 (2 mmol, 284 mg), or Me3Si+ CHB11Cl11 (2 mmol, 1.34 g) are
added at –78°C, followed by stirring 30 min at this temperature and 2 h at
–40° C. Half of the solvent is pumped off, and by slow addition of 30 mL
hexane the salt is crystallized. The product is filtered off, washed 3x with
20 mL hexane and dried in vacuum. Compound 14 is measured after
addition of little CD2Cl2 by NMR.
[Ad2SeCH2CH2SiMe2tBu]+ CHB11Cl11– (24)
Yield 1.32
g
(65%). ESI-MS (CH3CN): [491.2597]+ (C28H47SeSi+),
[521.7698]– (CHB11Cl11–). 77Se NMR (CD2Cl2) δ = 39.1. 13C NMR (CD2Cl2)
δ = 111.12 (ring C), 46.73 (CHB11Cl11–), 39.81 (2xCH2), 39.73 (2xCH2),
39.52 (2xCH2), 38.51 (2xCH2), 36.52 (2xCH2), 33.96 (2xCH), 31.55 (2xCH),
28.22 (CH2Se), 26.79 (4xCH), 26.11 (CMe3), 16.64 (CMe3), 12.03 (CH2Si),
–6.78 (MeSi). 11B NMR (CD2Cl2) δ = –2.52, –10.14, –13.18.
Seleniranium Salts 17, 25, according to method B
[Ad2SeCH2CH2CN]+ SbCl6– (17)
Yield 0.67
g
(66%). ESI-MS (CH3CN): [402.1730]+ (C23H32NSe+),
Method B: R2S2 or R2Se2/SO2Cl2/SbCl5/1.
[334.7094]– (SbCl6–). 77Se NMR (CD2Cl2) δ = 27.4. 13C NMR (CD2Cl2) δ =
115.01(CN), 100.00 (ring C), 40.28 (CH2), 39.99 (CH2), 39.87 (CH2), 38.58
(CH2), 36.53 (CH2), 34.58 (CH), 31.82 (CH), 26.90 (CH), 26.81 (CH), 23.82
(CH2Se), 16.86 (CH2CN).
15 mL dry CH2Cl2 are condensed on disulfide 7 (1 mmol, 351 mg), 10 (1
mmol, 172 mg), or diselenide 15 (1 mmol, 266 mg), 22 (1 mmol, 445 mg)
at –196°C. SO2Cl2 (1.1 mmol, 135 mg) is added at –20°C, followed by
stirring for 30 min at this temperature. SbCl5 (2 mmol, 598 mg) is slowly
added at –78°C, followed by stirring for 10 min at this temperature. Then
Ad=Ad 1 (2 mmol, 537 mg) is added and stirred for 2 h at –40°C. Half of
the solvent is pumped off, and by slow addition 30 mL hexane
crystallization initiated. The salt is filtrated off, washed 3x with 20 mL
hexane and dried in vacuum.
Single crystals are obtained by slow addition of Et2O into a solution CH2Cl2
at –20°C until beginning clouding sets in, and slow cooling from –20°C to
–80°C.
[Ad2SeCH2CH2SiMe2tBu]+ SbCl6– (25)
Yield 1.37 g (93%). ESI-MS (CH3CN): [491.2635]+ (C28H47SeSi+),
[334.7133]– (SbCl6–).
Thiiranium Salts 5, 9, 11, according to method A
Single crystals are obtained by slow addition of Et2O into a solution CH2Cl2
at –20°C until beginning clouding sets in, and slow cooling from –20°C to
–80°C.
Single crystals of the chloroethyl compound 26 are obtained in the same
manner.
[Ad2SCH2CH2SiMe3]+ Tf2N– (5)
Yield 0.99 g (73%). ESI-MS (CH3CN/CH2Cl2): [401.2692]+ (C25H41SSi+),
[279.9180]– (C2F6NO4S2–). 13C NMR (CD2Cl2) δ = 119.88 (q, (1JF,C = 321.9
Hz, CF3), 95.87 (ring C), 38.55 (2xCH2), 38.19 (2xCH2), 38.08 (2xCH2),
37.02 (2xCH2), 36.07 (2xCH2), 33.57 (2xCH), 30.31 (2xCH), 27.53 (CH2S),
26.50 (4xCH), 16.17 (1JSi,C = 42.5 Hz, CH2Si), –2.66 (1JSi,C = 52.0 Hz,
CH3Si). 29Si NMR (CD2Cl2)) δ = 3.52.
Attempts to dealkylate the Thiiranium Salts, the Thiiranes 27 und 30
[Ad2SCH2CH2SiMe2tBu]+ Tf2N– (9)
Cleavage of the Me3SiCH2CH2 group?
Yield 1.16
g
(80%). ESI-MS (CH3CN): [443.3198]+ (C28H47SSi+),
A solution of Bu4NF in THF (2 mL 1M, 2 mmol) is added to the thiiranium
salt 5 (1 mmol, 682 mg), dissolved in 5 ml dry THF at –196°C, followed by
2 h stirring at –78°C. The solvent is removed completely and the remainder
[279.9248]– (C2F6NO4S2–). 13C NMR (CD2Cl2)) δ = 119.83 (q, 1JF,C = 321.6
Hz, CF3), 96.15 (ring C), 38.57 (2xCH2), 38.21 (2xCH2), 38.09 (2xCH2),
37.03 (2xCH2), 36.05 (2xCH2), 33.56 (2xCH), 30.31 (2xCH), 27.91 (CH2S),
7
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is chromatographed in a mixture of CH2Cl2 (10 mL) and hexane (20 mL)
with silica gel.
27: Yield 210 mg (70%).
[Ad2C2SCH2CH2SiMe3]+ Tf2N– (35)
Yield 35 934 mg (66%). ESI-MS (CH3CN): [427.2832]+ (C27H43SSi+),
[279.9196]– (C2F6NO4S2–).
One-Pot Method
[Ad2C2SCH2CH2SiMe2tBu]+ Tf2N– (36)
The thiiranium salt [Ad2SCH2CH2SiMe3]+ BF4 is made by reacting 1 (2
Yield 36 1.94 g (65%). ESI-MS (CH3CN): [469.3356]+ (C30H49SSi+),
[279.9232]– (C2F6NO4S2–). 13C NMR (CD2Cl2) δ = 119.84 (q, 1JF,C = 321.5
Hz, CF3), 113.28 (ring C), 43,47 (SCH2), 40,04 (Ad, CH2), 35.42 (Ad, CH2),
34.56 (CMe3), 27.59 (CMe3), 26.00 (Ad, CH), 16.48 (Ad, Cq), 10.43
(CH2Si), –6.96 (MeSi). 29Si NMR (CD2Cl2) δ = 10.27.
–
mmol, 537 mg), (Me3SiCH2CH2S)2 (4), XeF2 (1 mmol, 169 mg), and
BF3·OEt2 (2 mmol, 284 mg) in 15 mL CH2Cl2 according to method A. Into
the solution Bu4NF in THF (4 mL 1M, 4 mmol) is added dropwise at –78°C,
followed by stirring for 2 h at –40°C. The solvents are pumped off and the
remainder is chromatographed in a mixture of CH2Cl2 (10 mL) and hexane
(20 mL) with silica gel.
Single crystals of 36 are obtained by careful addition of Et2O and pentane
to a solution in CH2Cl2 until clouding, filtration and slow cooling from room
temperature to –80°C (CH2Cl2/Et2O/pentane 1:1:1).
27: Yield 600 mg (100 %). EI-MS: 300 (33, M+, C20H28S), 268 (100, M+-S).
13C NMR (CDCl3) δ = 71.61 (ring C), 38.72 (4xCH2), 38.53 (4xCH2), 37.91
(2xCH2), 35.06 (4xCH), 27.87 (2xCH), 27.27 (2xCH).
Attempts to dealkylate Thiirenium Salts
Thiirenium salt 35 (1 mmol, 708 mg) are dissolved in 5 mL dry CH2Cl2 and
at –78°C a solution of Bu4NF in THF (2 mL 1M, 2 mmol) is added dropwise.
After stirring for 2 h at this remperature and 3 h at –60°C half of the solvent
is pumped off, some CD2Cl2 is added.
The thiiranium salt [C8H14SCH2CH2SiMe3]+ BF4 is prepared from cis-
–
cyclooctene (28) (2 mmol, 220 mg), (Me3SiCH2CH2S)2 (4), XeF2 (1 mmol,
169 mg) and BF3·OEt2 (2 mmol, 284 mg) in 15 mL CH2Cl2 according to
method A, and reacted and worked up in the same manner as described
for 27 with 2 mmol Bu4NF (2 mL 1 M in THF).
13C NMR (CD2Cl2, at –60°C) δ = 86.66, 42.76, 35.78, 28.56, 27.64
1
(AdCCAd 3); 119.38 (q, JF,C = 321.1 Hz, Tf2N–); 57.20, 23.12, 19.19,
13.28 (Bu4N+); 67.28, 25.23 (THF); 54.17 (CH2Cl2); –2.67 (4).
Thiirane 30: Yield 190 mg (67%). EI-MS: 142 (74, M+, C8H14S), 109 (64,
M+-SH), 67 (100). 13C NMR (CD2Cl2) δ = 41.09 (ring C), 29.67 (CH2), 29.45
(CH2), 26.43 (CH2).
Crystal structure determinations: Single crystals are grown by slow cooling
to –80°C in appropriate solvents and transferred onto the diffractometer
under cooling and exclusion of moisture: Bruker Smart CCD 1000 TU
diffractometer, Mo-K irradiation, scan width 0.3deg in , full sphere by
2400 frames, usually 20 sec per frame. After multi-scan absorption
corrections (SADABS) by equalizing symmetry-equivalent reflections. The
structures are solved and refined with the SHELX programs.[47] All atoms
except hydrogen are refined anisotropically. Hydrogen atoms are refined
isotropically in positions located by difference fourier maps or placed in
pre-calculated positions, depending on the quality of the data contain the
supplementary crystallographic data for these compounds. The data can
be obtained free of charge from the Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif. The experimental
details of all determined structures of this paper are collected in Table S2
in the supporting information. The structure figures have been
generated with the program DIAMOND.[48]
Thiirane 30 is also obtained from trans-cyclooctene (29) in the same
manner. Yield 30 250 mg (44%). 13C NMR (CD2Cl2) δ = 41.11 (ring C),
29.66 (CH2), 29.45 (CH2), 26.42 (CH2).
Cleavage of the tBuMe2SiCH2CH2 group?
Thiiranium salt 9 (1 mmol, 724 mg) is reacted in 5 mL dry THF at –78°C
with a solution of Bu4NF in THF (2 mL 1M, 2 mmol), followed by stirring for
2 h at this temperature. The solvent is pumped off completely in vacuum.
The remainder is dissolved in CH2Cl2 (10 mL) and hexane (20 mL) and
chromatographed over silica gel.
The 13C NMR spectrum shows the presence of alkene 1 and disulfide 4 as
main products, and thiirane 27 less than 10% in the product mixture.
Cleavage of the NCCH2CH2 group?
Thiiranium salt 11 (1 mmol, 635 mg), dissolved in 5 mL THF, is reacted
with CsOH (2.5 mmol, 375 mg) in 3 mL H2O or MeOH for 30 min at –40°C,
and stirred for 30 min at this temperature and 3 h at 0°C. After removal of
the solvent the mixture is chromatographed.
Acknowledgements
13C NMR spectra indicate a mixture of thiiran 27 and alkene 1 in the ratio
1:1 (reaction in MeOH) and 3:1 (reaction in H2O).
We thank the Deutsche Forschungsgemeinschaft (project PO
1503/2) and the Fonds der Chemischen Industrie for support of
this work.
Single crystals of the thiiranes 27 and 30 are obtained by slow cooling of
solutions in pentane from room temperature to –80°C.
Attempts to dealkylate Seleniranium Salts
Conflict of interest
The seleniranium salt [Ad2SeCH2CH2SiMe3]+ Tf2N– (14) is prepared by
reacting (Me3SiCH2CH2Se)2 (13) (2 mmol, 537 mg), XeF2 (1 mmol, 169
mg), and Tf2NSiMe3 (2 mmol, 707 mg) in 15 mL CH2Cl2 according to
method A. A solution of Bu4NF in THF (4 mL 1M, 4 mmol) is added
dropwise to the reaction mixture at –78°C, followed by stirring for 30 min
at –78°C and 2 h and at –40°C. Half of the solvent is pumped off in vacuum,
some CD2Cl2 is added, and the NMR of this solution is measured at –40°C.
The authors declare no conflict of interest.
Keywords: Selenium · Sulfur · X-ray diffraction · NMR
spectroscopy · ab–initio calculations.
[Ad2SeCH2CH2SiMe3]+ BF4 made from 1, 13, XeF2, and BF3·OEt2 are
–
[1]
a) D. Pettitt, G. Helmkamp, J. Org. Chem. 1964, 29, 2702 – 2706; b) G.
Capozzi, O. De Lucchi, V. Lucchini, G. Modena, Tetrahedron Lett. 1975,
16, 2603 – 2604; c) J. Bolster, R. M. Kellogg, J. Chem. Soc. Chem.
Commun. 1978, 630 – 631; d) E. Akgün, K. Hartke, T. Kämpchen, Arch.
Pharm. 1981, 314, 72 – 75; e) X. Huang, R. J. Batchelor, F. W. B.
Einstein, A. J. Bennet, J. Org. Chem. 1994, 59, 7108 – 7116; f) M.
Fachini, V. Lucchini, G. Modena, M. Pasi, L. Pasquato, J. Am. Chem.
Soc. 1999, 121, 3944 – 3950; g) S. E. Denmark, T. Vogler, Chem. Eur.
J. 2009, 15, 11737 – 11745; h) L. Pasquato, G. Modena, Chem.
Commun. 1999, 1469 – 1470; i) Y. Sugihara, Y. Aoyama, J. Nakayama,
Chem. Lett. 2001, 980 – 981.
reacted with Bu4NF in the same manner.
13C NMR (CD2Cl2, at –40°C) δ = 132.86, 39.26, 36.99, 31.59, 28.36
(Ad=Ad 1); 24.64, 18.95, –2.40 (diselenide 13); 119.59 (q, 1JF,C = 321.1 Hz,
Tf2N–); 57.86, 23.40, 19.46, 13.40 (Bu4N+); 67.59, 25.44 (THF); 54.16
(CH2Cl2). 77Se NMR (CD2Cl2, at –40° C) δ = 339.9 (diselenide 13) and
1187.5 (Me3SiCH2CH2SeF3 32), signal intensity 13/32 2:1.
Syntheses of the Thiirenium Salts 34–36
Onto alkyne 2 (2 mmol, 277 mg), 3 (2 mmol, 589 mg) and disulfide 4 (1
mmol, 267 mg); 7 (1 mmol, 351 mg) 15 mL dry CH2Cl2 are condensed at
–196°C. At –78°C XeF2 (1 mmol, 169 mg) and BF3·OEt2 (2 mmol, 284 mg)
or Tf2NSiMe3 (2 mmol, 707 mg) are added, and stirred at this temperature
30 min und 2 h at –40°C . Half of the solvent is pumped off and after slow
addition of 30 mL hexane the salt is crystallized. The product is filtered off,
washed 3x with 20 mL hexane and dried in vacuum.
[2]
a) G. Capozzi, O. De Lucchi, V. Lucchini, G. Modena, J. Chem. Soc.,
Chem. Commun. 1975, 248 – 249; b) G. Capozzi, V. Lucchini, G.
Modena, P. Scrimin, Tetrahedron Lett. 1977, 18, 911 – 912; c) V.
Lucchini, G. Modena, G. Valle, G. Capozzi, J. Org. Chem. 1981, 46,
4120 – 4124, d) A. Shimizu, S. Horiuchi, R. Hayashi, K. Matsumoto, Y.
Miyamoto, Y. Morisawa, T. Wakabayashi, J. Yoshida, Arkivoc 2018, ii,
97 – 113.
[3]
[4]
[5]
H. Poleschner, K. Seppelt, Angew. Chem. Int. Ed. 2008, 47, 6461 – 6464;
Angew. Chem. 2008, 120, 6561 – 6564.
H. Poleschner, K. Seppelt, Angew. Chem. Int. Ed. 2013, 52, 12838 –
12842; Angew. Chem. 2013, 125, 13072 – 13077.
–
[tBu2C2SCH2CH2SiMe3]+ BF4 (34). Yield 545 mg (76%). ESI-MS
(CH3CN/CH3OH): [271.1930]+ (C15H31SSi+), [87.0097]– (BF4–). 13C NMR
(CD2Cl2) δ = 114.84 (ring C), 42.20 (CH2S), 32.96 (CMe3), 27.69 (CMe3),
13.79 (CH2Si), –2.48 (MeSi).
H. Poleschner, K. Seppelt, Chem. Eur. J. 2018, 24, 17155 – 17161.
8
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Chemistry - A European Journal
FULL PAPER
[6]
a) J. Bock, C. G. Daniliuc, K. Bergander, C. Mück-Lichtenfelda, U.
Hennecke, Org. Biomol. Chem. 2019, 17, 3181 – 3185; b), S. E.
Denmark, W. R. Collins, M. D. Cullen, J. Am. Chem. Soc. 2009, 131,
3490 – 3492.
[25] a) C. Ascheberg, J. Bock, F. Buß, C. Mück-Lichtenfeld, C. G. Daniliuc, K.
Bergander, F. Dielmann, U. Hennecke, Chem. Eur. J. 2017, 23, 11578-
11586; b); b) X. Huang, R. J. Batchelor, F. W. B. Einstein, A. J. Bennet,
J. Org. Chem. 1994, 59, 7108-7116;
[7] a) H. Poleschner, M. Heydenreich, K. Spindler, G. Haufe, Synthesis 1994,
1043 – 1049; b) H. Poleschner, M. Heydenreich, U. Schilde, Eur. J. Inorg.
Chem. 2000, 1307 – 1313; c). H. Poleschner, K. Seppelt, J. Chem. Soc.,
Perkin Trans. 1 2002, 2668 –2672.
[26] R. Destro, V. Lucchini, G. Modena, L. Pasquato, J. Org. Chem. 2000,
65, 3367-3370.
[27] A. Krief, C. Delmotte, W. Dumont, Tetrahedron 1997, 53, 12147 –
12158.
[8]
K. Fujita, K. Murata, M. Iwaoka, S. Tomoda, Tetrahedron 1997, 53, 2029
– 2048.
R. Déziel, E. Malenfant, C. Thibault, Tetrahedron Lett. 1998, 39, 5493 –
[28] P. Salama, C. Bernard, Tetrahedron Lett. 1995, 36, 5711 – 5714.
[29] J. A. Soderquist, I. Rivera, A. Negron, J. Org. Chem. 1998, 54, 4051 –
4055.
[9]
5496.
[30] a) W. Adam, R. M. Bargon, Eur. J. Org. Chem. 2001, 1959-1662; b) W.
Adam, R. M. Bargon, Chem. Commun. 2001, 1910-1911.
[31] M. Arisawa, T. Ichikawa, M. Yamaguchi, Chem. Commun. 2015, 8821-
8824.
[32] H. Poleschner, K. Seppelt, Chem. Eur. J. 2004, 10, 6565 – 6574.
[33] H. Poleschner, S. Ellrodt, M. Malischewski, J. Nakatsuji, C. Rohner, K.
Seppelt, Angew. Chem. Int. Ed. 2012, 51, 419 – 422; Angew. Chem. 2012,
124, 433 – 437.
[10] H. Takada, Y. Nishibayashi, S. Uemura, J. Chem. Soc., Perkin Trans. 1
1999, 1511 – 1516.
[11] T. G. Back, Z. Moussa, Org. Lett. 2000, 2, 3007 – 3009.
[12] S. S. Khokhar, T. Wirth, Angew. Chem. Int. Ed. 2004, 43, 631 – 633.
Angew. Chem. 2004, 116, 641 – 643
[13] M. Tiecco, L. Testaferri, C. Santi, C. Tomassini, R. Bononi, F. Marini, L.
Bagnoli, A. Temperini, Org. Lett. 2004, 6, 4751 – 4753.
[14] K. Okamoto, Y. Nishibayashi, S. Uemura, A. Toshimitsu, Angew. Chem.
Int. Ed. 2005, 44, 3588 – 3591; Angew. Chem. 2005, 117, 3654 – 3657.
[15] a) M. Saito,J. Nakayama, in Science of Synthesis Vol. 39 (Ed. N.
Kambe, R. Noyori) Georg Thieme, Stuttgart New York, 2008, p 589 –
658; b) W. Ando, N. Choi, N. Tokitoh, Comprehensive Heterocyclic
Chemistry II, (Ed. A. Pawa), 1996, 1, 173 – 240.
[16] M. Saito,J. Nakayama, in Science of Synthesis Vol. 39 (Ed. N. Kambe,
R. Noyori) Georg Thieme, Stuttgart New York, 2008, p. 1023 – 1032.
[17] a) T. H. Chan, J. R. Finkenbine, Tetrahedron Lett. 1974, 2091 – 2094;
b) D. Van Ende, A. Krief, Tetrahedron Lett. 1975, 2709 – 2712; c) K.
Okuma, G. Koda, S. Okumura, A. Ohno, Chem. Lett. 1996, 609 – 610;
d) A. Zhou, M. Segi, T. Nakajima, Tetrahedron Lett. 2003, 44, 1179 –
1182.
[18] .a) W. Ando, Y. Kumamoto, N. Tokitoh, Tetrahedron Lett. 1987, 28,
2867 – 2870; b) W. Ando, Y. Kumamoto, N. Tokitoh, J. Phys. Org.
Chem. 1988, 1, 317 – 332; c) S. Watanabe, T. Kawashima, R. Okazaki,
Chem. Lett. 1994, 1289 – 1292; d) S. Dolai, P. Dutta, B. B. Muhoberac,
C. D. Irving, R. Sardar, Chem. Mater. 2015, 27, 1057 – 1070.
[19] H. Braunschweig, P. Constantinidis, T. Dellermann, W. C. Ewing, I.
Fischer, M. Hess, F. R. Knight, A. Rempel, C. Schneider, S. Ullrich, A.
Vargas, J. D. Woollins, Angew. Chem. Int. Ed. 2016, 55, 5606 – 5609;
Angew. Chem. 2016, 128, 5697 – 5700.
[34] J. Beckmann, M. Hesse, H. Poleschner, K. Seppelt, Angew. Chem. Int.
Ed. 2007, 46, 8277 – 8280; Angew. Chem. 2007, 119, 8425 – 8428.
[35] a) G. Capozzi, O. de Lucchi, V. Luchhini, G. Modena, J. Chem. Soc.
Chem. Commun. 1975, 248 – 249; b) G. Capozzi,, V. Luchhini, G.
Modena, P. Scrimin, Tetrahedron Lett. 1977, 911 – 912.
[36] R. Destro, T. Pilati, M. Simonetta, J. Chem. Soc., Chem. Commun.
1977, 576-577.
[37] G. Haufe, G. Alvernhe, D. Anker, A. Laurent, C. Saluzzo, J. Org. Chem.
1992, 57, 714 – 719.
[38] K. Uneyama, M. Kanai, Tetrahedron Lett. 1990, 31, 3583 – 3586.
[39] F. Götzfried, W. Beck, Z. Naturforsch. 1983, 38b, 370 – 372.
[40] a) S. C. Brydon, Z. Ren, G. da Silva, S. F. Lim, G. N. Khairallah, M. J.
Rathjen, J. M. White, R. A. J. O’Hair, J. Phys. Chem. A 2019, 123, 8200
– 8207; b) V. A. Potapov, M. V. Musalov, E. O. Kurkutov, V. A. Yakimov,
A. G. Khabibulina, M. V. Musalova, S. V. Amosova, T. N. Borodina, A. I.
Albanov, Molecules 2020, 25, 194 – 211.
[41] CCDC-1993913 [Ad2SCH2CH2SiMe2tBu]+ SbCl6–·EtCN (8), CCDC-
1993912 [Ad2SCH2CH2CN]+ SbCl6–·CH2Cl2 (12), CCDC-1993938
[Ad2SeCH2CH2CN]+
SbCl6–·CH2Cl2
(17),
(25),
CCDC-1993916
CCDC-1993914
[Ad2SeCH2CH2SiMe2tBu]+ SbCl6–·CH2Cl2
[Ad2SeCH2CH2Cl]+ SbCl6–·(26), CCDC-1993911 thiirane Ad2S (27),
CCDC-1993917
C8H14
S
(30)
and
CCDC-1993910
[20] N. Tokitoh, W. Ando, in Science of Synthesis Vol. 9 (Eds. G. Maas, M.
Regitz) Georg Thieme, Stuttgart New York, 2001, p 43 – 63.
[21] a) A. Krantz, J. Laureni, J. Am. Chem. Soc. 1974, 96, 6768 – 6770; b)
M. Torres, A. Clement, J. E. Bertie, H. E. Gunning, O. P. Strausz, J.
Org. Chem. 1978, 43, 2490 – 2493; c) R. Schulz, A. Schweig,
Tetrahedron Lett. 1984, 25, 2337 – 2340; d) G. Burdzinski, M. Sliwa, Y.
Zhang, S. Delbeare, J. Phys. Chem. 2011, 115, 14300 – 14305; e) G.
Burdzinski, H. L. Luk, C. S. Reid, Y. Zhang, C. M. Hadad, M. S. Platz, J.
Phys. Chem. 2013, 117, 4551 – 4555; f) G. Burdzinski, M. Sliwa, Y.
Zhang, S. Delbeare, T. Pedzinski, J. Rehault, Photochem. Photobiol.
Sci. 2013, 12, 895 – 901; g) M-D. Su, ACS Omega 2018, 3, 3482 –
3488.
[Ad2C2SCH2CH2SiMe2tBu]+ Tf2N–·(36) contain the supplementary
crystallographic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. Further experimental details and
data of the X-ray single-crystal structure determinations are given in the
supporting information, Table S2.
[42] Gaussian 16, Revision A.03, M. J. Frisch, G. W. Trucks, H. B. Schlegel,
G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone,
G. A. Petersson, H. Nakatsuji, X. Li, M. Caricato, A. V. Marenich, J.
Bloino, B. G. Janesko, R. Gomperts, B. Mennucci, H. P. Hratchian, J. V.
Ortiz, A. F. Izmaylov, J. L. Sonnenberg, D. Williams-Young, F. Ding, F.
Lipparini, F. Egidi, J. Goings, B. Peng, A. Petrone, T. Henderson, D.
Ranasinghe, V. G. Zakrzewski, J. Gao, N. Rega, G. Zheng, W. Liang, M.
Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T.
Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, K. Throssell, J. A.
Montgomery, Jr., J. E. Peralta, F. Ogliaro, M. J. Bearpark, J. J. Heyd, E.
N. Brothers, K. N. Kudin, V. N. Staroverov, T. A. Keith, R. Kobayashi, J.
Normand, K. Raghavachari, A. P. Rendell, J. C. Burant, S. S. Iyengar, J.
Tomasi, M. Cossi, J. M. Millam, M. Klene, C. Adamo, R. Cammi, J. W.
Ochterski, R. L. Martin, K. Morokuma, O. Farkas, J. B. Foresman, and D.
J. Fox, Gaussian, Inc., Wallingford CT, 2016.
[43] G. A. Tolstikov, B. M. Lerman, T. A. Beliogaeva, Synth. Commun. 1991,
21, 877 – 879.
[44] K. J. Shea, J.-S. Kim, J. Am. Chem. Soc. 1992, 114, 3044 – 3051:
[45] a) G. Capozzi, R. Ottana, G. Romeo, F. Marcuzzi, Gazz. Chim. Ital.
1985, 115, 311 – 314; b) G. Capozzi, G. Romeo, F. Marcuzzi, J. Chem.
Soc. Chem. Commun. 1982, 959 – 960.
[46] G. Simchen, S. Jonas, J. Prakt. Chem, 1998, 340, 506 – 512.
[47] SHELXL-2014/7, G. M. Sheldrick, University of Goettingen, Germany,
2014.
[22] Y.Ono, Y. Sugihara, A. Ishi, J. Nakayama, J. Am. Chem. Soc. 2003,
125, 12114 – 12115.
[23] a) B. M. Anderson, M. G. Ranasinghe, J. T. Palmer, P. L. Fuchs, J. Org.
Chem. 1988, 53, 3127 – 3129; b) A. L. Schwan, D. Brillon, R. Default,
Can. J. Chem. 1994, 72, 235 – 333; c) K. Tani, T. Murai, S. Kato, J. Am.
Chem. Soc. 2002, 124, 5960 – 5961; d) D. R. Garud, M. Makimura, M.
Kotetsu, New. J. Chem. 2011, 35, 581 – 586; e) T. K. Tran, Q. Bricaud,
M. Ocafrain, P. Blanchard, J. Roncali, S. Lenfant, S. Godey, D.
Vuillaume, D. Rondeau, Chem. Eur. J. 2011, 17, 5628 – 5640; f) W. W.
Seidel, M. J. Meel, S. R. Hughes, F. Hupka, A. Villinger, Angew. Chem.
Int. Ed. 2011, 50, 12617 – 12620; Angew. Chem. 2011, 123, 12825 –
12828; g) T. Murai, T. Nonoyama, Tetrahedron 2012, 68, 10489 –
10495.
[24] a) G. Logan, C. Igunbor, G.-X. Chen, H. Davis, A. Simon, J. Salon, Z.
Huang, Synlett 2006, 1554 – 1558; b) K. Tram, X. Wang, H. Yan, Org.
Lett. 2007, 9, 5103 – 5106; c) L. Binet, J. M. Fabre, C. Montginoul, K.
Baek Simonsen, J. Becher, J. Chem. Soc. Perkin 1 1996, 783 – 788; d)
J. Caton-Williams, Z. Huang, Angew. Chem. Int. Ed. 2008, 47, 1723 –
1725; Angew. Chem. 2008, 120, 1747 –1749; e) T. Bsaibess, M.
Guerro, Y. Le Gal, D. Sarraf, N. Bellec, M. Fourmigué, F. Barrière, V.
Dorcet, T. Guizouarn, T. Roisnel, D. Lorcy, Inorg. Chem. 2013, 52, 2162
– 2173.
[48] DIAMOND Version 4.6.1 – K. Brandenburg, Crystal Impact, GbR 2019.
9
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FULL PAPER
Entry for the Table of Contents
Bu4NF
Bu4NF
E = Se
S
E+
E = S
Tf2N–
no Selenirane
Se
SiMe3
Bu4NF
S+
Tf2N–
no Thiirene
SiMe3
S
Helmut Poleschner,* Konrad Seppelt
Thiiranium salts [Ad2SCH2CH2SiMe3]+ X– are dealkylated to the thiirane Ad2S by F–.
Thiiranium
salts
[Ad2SCH2CH2SiMe2tBu]+ X–,
seleniranium
salts
__________ Page – Page
[Ad2SeCH2CH2SiMe3]+ X–, and thiirenium salts [Ad2C2SCH2CH2SiMe3]+ X– are not
dealkylated by F–. Instead they are cleaved at the chalcogene atom to the alkene
Ad=Ad and alkyne AdCCAd under liberation of RS+ and RSe+.
Attempts to synthesize a Thiirane,
Selenirane, and Thiirene by Dealkylation
of Chalcogeniranium and Thiirenium
Salts.
10
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