PhSeOTf-Et3N·3HF and PhSeSbF6-Et3N·3HF as new PhSe-F equivalents in the fluoroselenenylation of actylenes

Article abstract of DOI:10.1039/b207886b

The novel reagents PhSeOTf-Et₃N·3HF and PhSeSbF₆-Et₃N·3HF act as PhSe-F equivalents in the fluoroselenenylation of alkynes. Oct-4-yne, cycloundecyne and cyclododecyne, as well as the unsymmetrical alkynes Ph-C≡C-Me and Bu-C≡C-R (R = Me, Et, ⁱPr and ^tBu) give the corresponding (E)-fluoro(phenylseleno)alkenes in preparative yields. The reagent PhSeOTf-Et₃N·3HF gives a similar product composition of regioisomers to Ph₂Se₂-XeF₂ in addition reactions to Bu-C≡C-R. This is indicative of a similar reaction mechanism of the reagents. Probably a selenirenium ion acts as an intermediate. X-Ray single crystal structure analysis of (E)-1-fluoro-2-phenylselenocycloundecene confirms the trans-addition of [PhSe-F] to cycloundecyne.

Full text of DOI:10.1039/b207886b

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PhSeOTf–Et3Nؒ3HF and PhSeSbF6–Et3Nؒ3HF as new PhSe–F
equivalents in the fluoroselenenylation of acetylenes
Helmut Poleschner* and Konrad Seppelt
1
Institut für Chemie, Anorganische and Analytische Chemie, Freie Universität Berlin,
Fabeckstrasse 34-36, D-14195 Berlin, Germany. E-mail: hpol@chemie.fu-berlin.de.
E-mail: seppelt@chemie.fu-berlin.de.; Fax: (internat.) ϩ49(30)838 53310
Received (in Cambridge, UK) 12th August 2002, Accepted 10th October 2002
First published as an Advance Article on the web 5th November 2002
The novel reagents PhSeOTf–Et3Nؒ3HF and PhSeSbF6–Et3Nؒ3HF act as PhSe–F equivalents in the fluoro-
selenenylation of alkynes. Oct-4-yne, cycloundecyne and cyclododecyne, as well as the unsymmetrical alkynes
i
t
᎐
᎐
Ph–C᎐C–Me and Bu–C᎐C–R (R = Me, Et, Pr and Bu) give the corresponding (E)-fluoro(phenylseleno)alkenes
᎐
᎐
in preparative yields. The reagent PhSeOTf–Et3Nؒ3HF gives a similar product composition of regioisomers to
᎐
Ph Se –XeF in addition reactions to Bu–C᎐C–R. This is indicative of a similar reaction mechanism of the reagents.
᎐
2
2
2
Probably a selenirenium ion acts as an intermediate. X-Ray single crystal structure analysis of (E)-1-fluoro-2-
phenylselenocycloundecene confirms the trans-addition of [PhSe–F] to cycloundecyne.
Introduction
Results and discussion
Various PhSe–F equivalents have been described for the select-
ive introduction of fluorine via addition reactions to organic
substrates, for example, PhSeBr–AgF–ultrasound,1,2 PhSeCl–
The reaction of PhSeϩ XϪ (XϪ are anions of low nucleophilicity
such as SbF6 , TfOϪ, BF4Ϫ and TsOϪ) with alkynes in the pres-
Ϫ
ence of Et3Nؒ3HF was investigated. The mild FϪ donor Et3Nؒ
3HF is easy to handle and has already been successfully used in
numerous syntheses.18
AgF–MeCN,3 N-Phenylselenophthalimide (NPSP)–Pyؒ9HF,4–6
NPSP–Et3Nؒ3HF,6,7 Ph2Se2–XeF2
and the electrochemical
8,9
oxidation of Ph2Se2 in the presence of Et3Nؒ3HF.10,11 We have
reported an efficient synthesis of (E)-fluoro(organylseleno)-
alkenes by fluoroselenenylation of alkynes by the RSe–F
The seleno electrophiles are generated by bromination of
Ph2Se2 with Br2 in CH2Cl2, and subsequent reaction of the so
obtained PhSeBr with the silver salts Agϩ XϪ (XϪ: SbF6 , TfOϪ,
Ϫ
BF4 , TsOϪ). The thus formed PhSeϩ XϪ then reacts at 0 ЊC in
12,13
14
Ϫ
equivalents R2Se2–XeF2
and RSe–EMe3–XeF2 (E = Si,
Ge, Sn, Pb). The addition of [PhSe–F] to the unsymmetrical
the presence of Et3Nؒ3HF with oct-4-yne 1 as model alkyne,
forming the expected 4-fluoro-5-phenylselenooct-4-ene 9. The
relative molar amounts used were PhSeϩ XϪ:octyne:Et3Nؒ3HF
= 1:1:3, see Scheme 2.15–17
i
t
᎐
alkynes Bu–C᎐C–R (R = Me, Et, Pr and Bu) yields mixtures
᎐
of regioisomers (Scheme 1). The product composition as a
Scheme
1
Regioisomers from the addition of Ph2Se2–XeF2 to
᎐
Bu–C᎐C–R.
᎐
function of the size of R has been interpreted with the assump-
tion of an intermediate selenirenium ion C (Scheme 1) and its
nucleophilic ring opening reaction by the fluoride ion.12
A selenirenium ion has been characterized by 1H NMR
spectroscopy in the reaction of PhSeϩ SbF6 with but-2-yne.15
If selenirenium ions are indeed intermediates in the fluoro-
Ϫ
Ϫ
Scheme 2 Reactions of PhSeX–Et3Nؒ3HF (XϪ: SbF6Ϫ, TfOϪ, BF4
,
TsOϪ) with oct-4-yne.
selenenylation reactions of alkynes, ions generated from
Ϫ
PhSeϩ SbF6 and R–C᎐C–R should also react with external
᎐
᎐
fluoride forming fluoro(phenylseleno)alkenes. Such a reaction
This reaction as a synthetic method is accompanied by some
problems. In almost all experiments the undesired by product
bromo(phenylseleno)oct-4-ene 10 is detected by 77Se NMR
spectroscopy (δ = 398.2 ppm): with AgSbF6 up to 6%, with
AgOTf 8–16% and with AgBF4 and AgOTs even up to 60%, as
measured by 77Se NMR signal integration. Compound 10 was
independently synthesized by addition of PhSeBr to oct-4-yne
in CH2Cl2 (77Se NMR: δ = 398.8 ppm). This method for the
preparation of PhSeϩ XϪ is probably incomplete due to the low
᎐
should give, with Bu–C᎐C–R, a similar product composition
᎐
of regioisomers as the reaction with Ph2Se2–XeF2. By com-
bination of such strong benzeneselenenylation reagents as
PhSeSbF6,15 PhSeOTf,16 or PhSeOTs17 with suitable fluoride
sources, new, highly reactive selenenyl fluoride equivalents
should be obtainable which do not need expensive XeF2. The
investigation of such systems is of mechanistic and preparative
interest.
2668
J. Chem. Soc., Perkin Trans. 1, 2002, 2668–2672
This journal is © The Royal Society of Chemistry 2002
DOI: 10.1039/b207886b

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solubility of the silver salts in CH2Cl2. Unchanged PhSeBr can
then react to give 10. Yields with AgSbF6 are moderate,
50–56%, with AgOTf somewhat higher, 64–80%. In other
publications ArSeOTf, prepared from ArSeBr ϩ AgOTf in
alcohols or MeCN as solvents, is successfully used in reactions
with olefins.19–21 But these solvents cannot be used for our
reaction since they could interfere directly with the reaction.
Alkenes undergo oxyselenenylation with alcohols19,20 and
amidoselenenylation with MeCN.21 We obtained a complex
mixture without fluoroselenenylation in the reaction of
PhSeOTf with Et3Nؒ3HF and 1 in MeCN.
Bromine and the silver-free preparation of benzeneselenenyl
triflate PhSeOTf from benzeneseleninic anhydride (PhSeO)2O,
Ph2Se2 and trifluoromethanesulfonic acid anhydride Tf2O in
CH2Cl2 according to literature22 is an improvement for our
method (Scheme 3). PhSeOTf thus obtained in situ and in
High resolution mass spectra proved the assumed elemental
composition of the synthesized compounds. NMR spectra of
the products agree very well with those obtained from the
Ph2Se2–XeF2 and PhSe–EMe3–XeF2 reagents.12,14 14a/b–17a/b
were analyzed as mixtures. The assignment of the 13C, 19F and
77Se NMR spectra have been reported by us before.23 We can
assign the 77Se and 19F signals to the components of mixtures of
F/Se-compounds by means of new 77Se,19F{1H} HETCOR 2D
NMR measurements.24
Of interest is the distribution of regioisomers A and B in the
2
2
i
t
᎐
addition to Bu–C᎐C–R (R = Me, Et, Pr, Bu). The A:B ratio is
᎐
close to 1:1 with 51:49 for Bu/Me and 55:45 for Bu/Et, but
increases to 76:24 for Bu/iPr and particularly to 94:6 for Bu/tBu.
The A:B ratios were measured by 19F and 77Se NMR signal
integrations, and both values give the same results. The strong
similarity of the A:B ratio for both reagents PhSeOTf–Et3Nؒ
3HF and Ph2Se2–XeF2 shows that the mechanisms of both
reactions are closely related. For both reagents one can assume
the intermediate formation of a selenirenium ion. Nucleophilic
attack of the fluoride ion occurs preferentially at the Bu side in
the case of increased steric hindrance by R2 and A becomes the
main isomer (path a of Scheme 3). The formation of the B
isomer is hindered (path b of Scheme 3).
X-Ray single crystal structure of 1-fluoro-2-
phenylselenocycloundecene 11
X-Ray structures of the (E)-cycloundecene ring have been
published only for derivatives of cycloundecene-1-carboxylic
acid.25 The X-ray crystal structure analysis of fluoro(phenyl-
seleno)cycloundecene 11 is shown in Figure 1. It establishes
that the fluoroselenenylation of cycloalkynes is also a trans-
addition, [dihedral angles F–C17–C7–Se 179.9(4)Њ, C16–C17–
C7–C8 Ϫ177.9(8)Њ]. We have already reported on the trans-
13
addition of [PhSe–F] to acyclic alkynes with Ph2Se2–XeF2
14
and PhSe–EMe3–XeF2 (E = Si, Ge, Sn, Pb) and the X-ray
structures of the products. C–F, C᎐C and C–Se bonds in the
᎐
central F–C᎐C–Se molecular fragment of 11 are shorter than
᎐
in acyclic fluoro seleno alkenes.13,14 The large C–C–C angle
at the fluorinated C atom [C7–C17–C16 129.5(6)Њ] and the
small F–C–C angle towards the alkyl chain [F–C17–C16
111.1(5)Њ] are characteristic for such fluoro alkenes.13,14 The
general feature of this molecule is that the best plane of the
(CH )n ring is perpendicular to the F–C᎐C–Se plane. Viewed
᎐
2
in the direction of the C–F bond, a triangular form is visible
that is only interrupted at the corners by the C8–C9 and
C15–C16 bonds. The phenyl ring plane is situated opposite
to the eleven-membered ring and also almost perpendicular to
the F–C᎐C–Se plane [C1–Se–C7–C17 88.3(5)Њ]. In contrast to
᎐
an acyclic fluoro(arylseleno) alkene14 the phenyl ring is only
slightly torsioned against the Se–C7 bond [C7–Se–C1–C2
9.7(4)Њ]. The enlargement of almost all bond angles at the
sp3-hybridized C atoms of the ring as compared to 109.45Њ
indicates considerable ring strain. The dihedral angles in
the ring show six gauche conformations with angles around
60Њ [Se–C7–C8–C9 Ϫ68.2(9)Њ, C10–C9–C8–C7 Ϫ59.7(11)Њ,
C13–C12–C11–C10 61.6(13)Њ, C11–C12–C13–C14 77.9(13)Њ,
C17–C16–C15–C14 Ϫ57.0(11)Њ, C15–C16–C17–F Ϫ68.5(7)Њ].
Along two bonds (C10–C11 and C13–C14) an anti con-
formation with angles about 155Њ is observed. Finally, along
two bonds (C9–C10 and C14–C15) an unfavorable
almost eclipsed conformation exists [C8–C9–C10–C11
99.2(10)Њ, C13–C14–C15–C16 102.2(11)Њ]. If the eleven-
membered ring is viewed from the double bond, the atoms
C11, C12 and C13 appear almost linear and parallel to the
Scheme 3 Reactions of PhSeOTf–Et3Nؒ3HF with alkynes.
homogenous solution reacts with oct-4-yne in the presence of
Et3Nؒ3HF to give fluoro(phenylseleno)octene 9 in good yields
and high purity. Thus the PhSeOTf–Et3Nؒ3HF reagent was
reacted with a number of other alkynes: cycloundecyne 2,
᎐
cyclododecyne 3, unsymmetrical alkynes Ph–C᎐C–Me 4, and
᎐
2
2
i
t
᎐
Bu–C᎐C–R 5–8 (R = Me, Et, Pr, Bu). A 50% excess of the
᎐
selenium reagent (molar ratio PhSeOTf:alkyne:Et3Nؒ3HF =
1.5:1:3) was used. In all cases the synthesis of fluoro(phenyl-
seleno)alkenes 9, 13, and 14a/b–17a/b as well as of fluoro-
(phenylseleno)cycloalkenes 11 and 12 was successful, Scheme 3.
The PhSeOTf–Et3Nؒ3HF reagent shows somewhat higher
yields and shorter rection times in the fluoroselenenylation of
acetylenes than the earlier described reagents PhSeBr–AgF–
ultrasound,2 NPSP–Et3Nؒ3HF,6,7 and the electrochemical
oxidation of Ph2Se2 in presence of Et3Nؒ3HF.10,11 The yields of
products from individual compounds follow the trend of the
Ph2Se2–XeF2 reagent.12
C᎐C bond.
᎐
The planar-chiral trans-cycloalkene 11 is a racemic mixture.
The enantiomers crystallize separately. The measured crystal
contained the S enantiomer according to the rules of
chirality.26,27
J. Chem. Soc., Perkin Trans. 1, 2002, 2668–2672
2669

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Table 1 Crystallographic and experimental data for 11
Empirical formula
Molecular weight
Temperature
C17H23FSe
325.32
Ϫ150 ЊC
Monoclinic
Crystal system
a = 709.9(2) pm
b = 635.8(1) pm
c = 1676.6(3) pm
β = 90.42(1)Њ
P21
Space group
Volume
Z
Calculated density
Absorption coefficient
F(000)
756.8 × 106 pm3
2
1.428 g cmϪ3
2.48 mmϪ1
336.0
Crystal size
0.3 × 0.3 × 0.2 mm
1.21–30.93Њ
1.000/0.621
4699/1/175
1.070
0.0646
0.0675
Theta range for data collection
Max. and min. transmission
Data restraints/parameters
Goodness-of-fit on F 2
Final R values [I ≥ 2σ(I )]
R indices (all data)
Absolute structure parameter
0.1028
δ = 0), 77Se at 76.20 MHz (77Se reference: 60 vol% Me2Se in
CDCl3, δ = 0).
Ph2Se2, (PhSeO)2O, Tf2O, AgBF4 (Fluka), Et3Nؒ3HF,
AgSbF6, AgOTf (Aldrich), AgOTs, 1 (Merck) and 4 (Acros) are
commercial products. 5,28 6,29 30 and 831 were obtained follow-
7
ing literature procedures. Cycloalkynes 2 and 3 were prepared
by thermolysis of the corresponding cycloalkeno-1,2,3-
selenadiazole over copper powder.32
X-Ray crystal structure determination
A suitable crystal was mounted on a Bruker SMART CCD
1000 TM diffractometer and cooled to Ϫ150 ЊC. Mo-Kα (λ =
71.1069 pm) radiation, graphite monochromator, scan width of
0.3Њ in ω, exposure time of 20 s/frame, and detector crystal
distance 40 mm were used. A full shell of data up to 2θ = 62Њ
was measured by 1800 frames. Data were reduced to intensities,
corrected for background, and a semiempirical absorption cor-
rection was applied (SADABS). The structure was solved and
refined by use of the SHELXL programs.33,34 For experimental
details of the crystal structure see Table 1.†
Reactions of 1 with PhSeX [PhSeBr ؉ AgX] and Et3Nؒ3HF:
general procedure
A 50 ml Schlenk vessel containing 2 mmol Ph2Se2 (624 mg) was
filled with 20 ml dry CH2Cl2 on a vacuum line by cooling to
Ϫ196 ЊC. Br2 (2 ml, 1 M in CCl4, 2 mmol) was injected at room
temperature under argon, and the mixture was magnetically
Fig. 1 ORTEP-representation of the molecular structure of (E)-1-
fluoro-2-phenylselenocycloundecene 11 (thermal ellipsoids of 40%
probability, viewed from direction of the phenyl group (above) and
along the C–F bond (below). Selected bond lengths/pm and angles/Њ:
Se–C7 190.6(6), Se–C1 190.7(4), F–C17 135.3(7), C7–C17 126.8(9), C7–
C8 153.4(11), C16–C17 146.1(12); C7–Se–C1 99.71(19), C7–C17–C16
129.5(6), C17–C7–Se 121.6(6), C17–C7–C8 121.3(6), F–C17–C16
111.1(5); F–C17–C7–Se 179.9(4), C16–C17–C7–C8 Ϫ177.9(8), Se–C7–
C8–C9 Ϫ68.2(9), C10–C9–C8–C7 Ϫ59.7(11), C8–C9–C10–C11
99.2(10), C12–C11–C10–C9 Ϫ150.0(8), C13–C12–C11–C10 61.6(13),
C11–C12–C13–C14 77.9(13), C12–C13–C14–C15 Ϫ159.8(9), C13–
C14–C15–C16 102.2(11), C17–C16–C15–C14 Ϫ57.0(11), C15–C16–
C17–F Ϫ68.5(7), C1–Se–C7–C17 88.3(5), C7–Se–C1–C2 9.7(4).
Ϫ
stirred for 15 min. The silver salt AgX (4 mmol; XϪ: SbF6 ,
Ϫ
TfOϪ, BF4 , TsOϪ) was added at 0 ЊC under exclusion of mois-
ture and the reaction was stirred for 30 min at this temperature.
Into this dark green suspension simultaneously 12 mmol Et3Nؒ
3HF (1.93 g) and 4 mmol oct-4-yne 1 (441 mg) were injected,
and the color changed immediately to light yellow. The mixture
was further stirred for 1 h at 0 ЊC and 3 h at room temperature,
H2O (50 ml) was added. AgBr was removed by filtration of the
mixture over Celite and washing with 60 ml Et2O. The aqueous
solution was extracted twice with 50 ml Et2O, and the organic
layers were washed consecutively with 50 ml H2O, 50 ml
NaHCO3 solution, 50 ml H2O and 50 ml saturated NaCl
solution, and dried over Na2SO4. Colorless oils were obtained
after removal of the solvent and chromatography through a 10
cm long, 2 cm diameter silica gel column eluting with hexane.
Experimental
Mass EI spectra were measured with a Finnigan MAT 711
instrument at 80 eV electron excitation. High-resolution spectra
were measured by the peak-match method using PFK as the
reference substance. NMR spectra were measured with a JEOL
JNM-LA 400 spectrometer in 5 mm tubes at room temperature:
13C at 100.40 MHz (13C reference TMS in CDCl3, δ = 0 ppm),
19F at 376.00 MHz (19F reference: external CFCl3 in CDCl3,
† Crystallographic data (excluding structure factors) for the structure
reported in this paper have been deposited with the Cambridge Crystal-
lographic Data Centre. CCDC reference number 184423. See http://
www.rsc.org/suppdata/p1/b2/b207886b/ for crystallographic files in .cif
or other electronic format.
2670
J. Chem. Soc., Perkin Trans. 1, 2002, 2668–2672

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Reaction with AgSbF6: yield 9: 0.57–0.64 g (50–56%); sample
contained 6% 10. Yield 9 if 1.25 equiv. PhSeSbF6 used: 0.71 g
(62%) with 6% 10.
Reaction with AgOTf: yield 9: 0.73–0.91 g (64–80%); sample
contained 8–16% 10.
Reaction with AgBF4: mixture of 9 and 10 with 60% 10.
Reaction with AgOTs: mixture of 9 and 10 with 57% 10.
HR-MS: m/z Mϩ: 272.04922 (calculated for C13H17FSe:
272.04794, related to 80Se).
14a: δC (CDCl3) 17.75 (3JF, C = 7.9 Hz, C-1), 103.64 (2JF, C
=
21.5 Hz C-2), 162.81 (1JF, C = 265.9 Hz, C-3), 30.96 (2JF, C = 28.1
Hz, C-4), 29.08 (3JF, C = 0.8 Hz, C-5), 22.14 (C-6), 13.89, C-7);
Ph: 130.38 (4JF, C = 2.1 Hz, i-C), 130.76 (2JSe,C = 11.6 Hz, o-C),
3
129.19 (m-C), 126.55 (p-C); δF Ϫ91.83 (t, JF, H = 23.1 Hz, q,
4JF, H = 3.3 Hz); δSe 378.4 (3JSe,F = 18.7 Hz).
14b: δC 17.72 (2JF, C = 31.0 Hz, C-1), 160.16 (1JF, C = 263.8 Hz,
C-2), 109.82 (2JF, C = 20.3 Hz, C-3), 30.46 (3JF, C = 6.2 Hz, C-4),
30.65 (4JF, C = 1.7 Hz, C-5), 22.14 (C-6), 13.85 (C-7); Ph: 130.88
(4JF, C = 2.1 Hz, i-C), 130.25 (2JSe,C = 12.0 Hz, o-C), 129.16 (m-C),
Reaction of alkynes 1–8 with PhSeOTf [(PhSeO)2O ؉ Ph2Se2
؉Tf2O] and Et3Nؒ3HF: general procedure
A 50 ml Schlenk vessel was filled with 1 mmol (360 mg)
(PhSeO)2O and 2 mmol (624 mg) Ph2Se2 under exclusion of
moisture. Dry CH2Cl2 (20 ml) was condensed in at Ϫ196 ЊC. At
0 ЊC Tf2O (3 mmol, 846 mg) was injected under argon, followed
by 5 min magnetic stirring. Immediately a deep red color was
formed, and the solution became opaque. Alkyne 1–8 (4 mmol)
and 12 mmol Et3Nؒ3HF (1.93 g) were injected simultaneously,
and the deep red color changed to light yellow. After 1 h of
stirring at 0 ЊC and 4 h at room temperature (1, 5–7) or 6 h
(2–4, 8), H2O (100 ml) was added, and the aqueous solution was
extracted twice with 70 ml Et2O. The organic layer was washed
consecutively with 60 ml H2O, 60 ml NaHCO3 solution, 60 ml
H2O, and 60 ml saturated NaCl solution, and dried over
Na2SO4. A solution of 13 was shaken with 1 g NaBH4 in 20 ml
H2O until the yellow color disappeared, then washed with twice
100 ml H2O. Further treatment was similar to that described
above.
3
4
126.37 (p-C); δF Ϫ84.03 (q, JF, H = 17.3 Hz, t, JF, H = 2.6 Hz);
δSe 341.3 (3JSe,F = 15.8 Hz).
(E )-4-Fluoro-3-phenylselenooct-3-ene 15a and (E )-3-fluoro-4-
phenylselenooct-3-ene 15b. Yield (colorless oil): 0.79 g (69%).
HR-MS: m/z Mϩ: 286.06573 (calculated for C14H19FSe:
286.06359, related to 80Se).
15a: δC (CDCl3) 13.63 (4JF, C = 1.7 Hz, C-1), 24.19 (3JF, C = 7.0
Hz, C-2), 111.41 (2JF, C = 20.7 Hz, C-3), 162.98 (1JF, C = 267.1 Hz,
C-4), 31.13 (2JF, C = 28.1 Hz, C-5), 29.09 (C-6), 22.14 (C-7), 13.92
(C-8); Ph: 130.99 (4JF, C = 1.7 Hz, i-C), 130.40 (o-C), 129.15
3
4
(m-C), 126.38 (p-C); δF Ϫ92.73 (t, JF, H = 23.1 Hz, t, JF, H
2.5 Hz); δSe 331.8 (3JSe,F = 17.3 Hz).
=
15b: δC 11.62 (C-1), 25.08 (2JF, C = 28.9 Hz, C-2), 164.57 (1JF, C
= 267.1 Hz, C-3), 108.95 (2JF, C = 21.1 Hz, C-4), 30.37 (3JF, C = 5.8
Hz, C-5), 30.72 (4JF, C = 1.7 Hz, C-6), 22.11 (C-7), 13.87 (C-8);
Ph: 131.02 (4JF, C = 1.7 Hz, i-C), 130.33 (o-C), 129.14 (m-C),
126.38 (p-C); δF Ϫ94.10 (t, JF, H = 22.7 Hz, t, JF, H = 2.7 Hz);
δSe 335.6 (3JSe,F = 15.8 Hz).
(E )-4-Fluoro-5-phenylselenooct-4-ene 9. Yield (colorless oil):
0.8 g (70%); HR-MS: m/z Mϩ: 286.06530 (calculated for
C14H19FSe: 286.06359, related to 80Se); δC (CDCl3) 13.51 (C-1),
20.42 (C-2), 33.30 (2JF, C = 28.1 Hz, C-3), 163.34 (1JF, C = 267.1
Hz, C-4), 109.84 (2JF, C = 20.7 Hz, C-5), 32.45 (3JF, C = 5.8 Hz,
3
4
(E )-4-Fluoro-2-methyl-3-phenylselenooct-3-ene 16a and (E )-
3-fluoro-2-methyl-4-phenylselenooct-3-ene 16b. Yield (colorless
oil): 0.69 g (58%). HR-MS: m/z Mϩ: 300.08224 (calculated for
C15H21FSe: 300.07924, related to 80Se).
C-6), 21.79 (4JF, C = 1.7 Hz, C-7), 13.41 (C-8); Ph: 130.93 (4JF, C
=
1.7 Hz, i-C), 130.44 (2JSe,C = 11.6 Hz, o-C), 129.15 (m-C), 126.40
(p-C); δF Ϫ91.84 (t, 3JF, H = 23.0 Hz); δSe 335.1 (3JSe,F = 16.6 Hz).
16a: δC (CDCl3) 21.89 (4JF, C = 2.1 Hz, C-1), 29.41 (3JF, C = 7.0
Hz, C-2), 116.39 (2JF, C = 18.2 Hz, C-3), 164.07 (1JF, C = 268.8 Hz,
C-4), 31.56 (2JF, C = 28.1 Hz, C-5), 28.87 (C-6), 22.18 (C-7), 13.86
(C-8); Ph: 132.60 (4JF, C = 2.1 Hz, i-C), 129.17 (o-C), 129.02
(E )-1-Fluoro-2-phenylselenocycloundecene 11. Yield: 0.65 g
(50%), colorless crystals, mp 52.5–53.5 ЊC (MeOH); HR-MS:
m/z Mϩ: 326.09643 (calculated for C17H23FSe: 326.09489,
related to 80Se); δC (CDCl3) 163.28 (1JF, C = 265.3 Hz, C-1),
112.15 (2JF, C = 20.2 Hz, C-2), 31.38 (3JF, C = 5.0 Hz, C-3), 31.43
3
(m-C), 125.90 (p-C); δF Ϫ90.51 (t, JF, H = 23.1 Hz); δSe 276.8
(3JSe,F = 13.7 Hz).
(2JF, C = 28.9 Hz, C-11), 24.50 (JF, C = 1.7 Hz), 24.70, 25.46 (JF, C
=
16b: δC 19.64 (3JF, C = 0.8 Hz, C-1), 30.51 (2JF, C = 27.3 Hz, C-2),
167.04 (1JF, C = 271.3 Hz, C-3), 107.66 (2JF, C = 21.5 Hz, C-4),
30.33 (3JF, C = 6.6 Hz, C-5), 30.72 (4JF, C = 1.7 Hz, C-6), 22.04
(C-7), 13.92 (C-8); Ph: 131.07 (4JF, C = 2.1 Hz, i-C), 130.31 (o-C),
2.1 Hz), 25.71, 26.03 (JF, C = 2.1 Hz), 26.31, 26.69; Ph: 130.92
(4JF, C = 1.2 Hz, i-C), 130.55 (2JSe,C = 12.0 Hz, o-C), 129.14 (m-C),
126.46 (p-C); δF Ϫ89.93 (s); δSe 337.4 (s).
3
129.15 (m-C), 126.34 (p-C); δF Ϫ107.73 (d, JF, H = 30.6 Hz, t,
4JF, H = 2.7 Hz); δSe 331.1 (3JSe,F = 16.6 Hz).
E )-1-Fluoro-2-phenylselenocyclododecene 12. Yield (colorless
oil): 0.96 g (71%); HR-MS: m/z Mϩ: 340.11355 (calculated
for C18H25FSe: 340.11054, related to 80Se); δC (CDCl3) 163.64
(1JF, C = 265.5 Hz, 2JSe,C = 16.1 Hz, C-1), 110.01 (2JF, C = 20.7 Hz,
(E )-4-Fluoro-2,2-dimethyl-3-phenylselenooct-3-ene 17a and
(E )-3-Fluoro-2,2-dimethyl-4-phenylselenooct-3-ene 17b. Yield
(colorless oil): 0.31 g (25%). HR-MS: m/z Mϩ: 314.09622
(calculated for C16H23FSe: 314.09489, related to 80Se).
1JSe,C = 99.7 Hz, C-2), 28.46 (3JF, C = 5.0 Hz, C-3), 31.04 (2JF, C
=
28.9 Hz, C-12), 23.77, 23.92, 24.47, 25.29 (double intensities),
25.36 (JF, C = 1.7 Hz), 25.73, 26.40; Ph: 130.69 (4JF, C = 1.2 Hz,
i-C), 130.55 (2JSe,C = 11.6 Hz, o-C), 129.11 (m-C), 126.42 (p-C);
δF Ϫ88.32 (d, 3JF, H = 22.0 Hz); δSe 325.1 (3JSe,F = 19.4 Hz).
17a: δC (CDCl3) 31.13 (4JF, C = 4.5 Hz, C-1), 37.54 (C-2),
1
117.62 (2JF, C = 14.1 Hz, JSe,C = 105.7 Hz, C-3), 165.48 (1JF, C
=
275.4 Hz, JSe,C = 17.0 Hz, C-4), 33.59 (2JF, C = 29.4 Hz, C-5),
29.26 (C-6), 22.15 (C-7), 13.88 (C-8); Ph: 133.53 (4JF, C = 2.5 Hz,
i-C), 128.62 (2JSe,C = 12.0 Hz, o-C), 129.07 (m-C), 125.67 (p-C);
δF Ϫ78.82 (t, 3JF, H = 23.4 Hz); δSe 341.6 (3JSe,F = 14.4 Hz).
17b: δC 167.75 (1JF, C = 270.0 Hz, C-3), 107.85 (2JF, C = 27.7 Hz,
C-4); δF Ϫ84.54 (s); δSe 331.1 (3JSe,F = 20.2 Hz).
2
(E )-1-Fluoro-1-phenyl-2-phenylselenoprop-1-ene 13. Yield
(colorless oil): 0.31 g (27%); HR-MS: m/z Mϩ: 292.01834
(calculated for C15H13FSe: 292.01665, related to 80Se); δC
(CDCl3) 157.36 (1JF, C = 258.0 Hz, 2JSe,C = 20.9 Hz, C-1), 106.28
1
(2JF, C = 24.0 Hz, JSe,C = 104.8 Hz, C-2), 18.59 (3JF, C = 7.4 Hz,
C-3); Ph: 132.52 (2JF, C = 29.4 Hz, i-C), 128.74 (3JF, C = 4.5 Hz,
o-C), 127.76 (m-C),129.29 (5JF, C = 1.2 Hz, p-C); SePh: 129.72
(4JF, C = 1.2 Hz, i-C), 131.74 (2JSe,C = 11.6 Hz, o-C), 129.18 (m-C),
(E )-4-Bromo-5-phenylselenooct-4-ene 10
To PhSeBr [prepared from 1 mmol Ph2Se2 (312 mg) and 1 mmol
Br2 (1 ml, 1 M in CCl4)] in 10 ml CH2Cl2 at room temperature,
oct-4-yne 1 (2 mmol, 220 mg) was added and the mixture was
stirred for 2 h at room temperature. After evaporation of the
solvent the product was chromatographed through a short silica
gel column with hexane. Yield 10 (colorless oil): 0.64 g (92%);
127.00 (p-C); δF Ϫ84.41 (4JF, H = 3.4 Hz); δSe 397.7 (3JSe,F
=
33.5 Hz).
(E )-3-Fluoro-2-phenylselenohept-2-ene 14a and (E )-2-fluoro-
3-phenylselenohept-2-ene 14b. Yield (colorless oil): 0.73 g (67%);
J. Chem. Soc., Perkin Trans. 1, 2002, 2668–2672
2671

View Article Online
HR-MS: m/z Mϩ: 345.98562 (calculated for C14H19BrSe:
345.98353, related to 80Se and 79Br); δC (CDCl3) 13.48 (C-1),
21.30 (C-2), 40.65 (C-3), 129.48 (C-4), 129.21 (C-5), 43.29 (2JSe,C
= 9.5 Hz, C-6), 21.87 (C-7), 13.03 (C-8); Ph: 130.59 (i-C), 132.07
(2JSe,C = 11.4 Hz, o-C), 129.13 (m-C), 127.04 (p-C); δSe 398.8.
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Acknowledgements
This work was supported by the Deutsche Forschungsgemein-
schaft and the Fonds der Chemischen Industrie. H. P. was
supported by the state of Berlin under the HSP III program.
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