New methodology for the conversion of epoxides to alkenes

Article abstract of DOI:10.1002/ejoc.200901264

Epoxides have been transformed in good yields to alkenes by a process involving (i) ring-opening of the epoxide with 2-mercaptobenzothiazole, (ii) oxidation of the derived ss-hydroxy thioethers to the corresponding sulfones, and (iii) thermal or base-promoted fragmentation of these sulfones to alkenes. The stereochemistry of the starting epoxide is transfer-red faithfully to the alkene product, because of the SN2 epoxide ring-opening reactions and the antiperiplanar SO₂ elimination reaction of the ss- alkoxysulfinate intermediates. This methodology may form the basis of a new protecting group strategy for alkenes.

Full text of DOI:10.1002/ejoc.200901264

FULL PAPER
DOI: 10.1002/ejoc.200901264
New Methodology for the Conversion of Epoxides to Alkenes
Feng-Ling Wu,[a] Benjamin P. Ross,[b] and Ross P. McGeary*[a,b]
Keywords: Alkenes / Epoxide / Olefination / Deoxygenation / Protecting groups
Epoxides have been transformed in good yields to alkenes
by a process involving (i) ring-opening of the epoxide with
2-mercaptobenzothiazole, (ii) oxidation of the derived β-hy-
droxy thioethers to the corresponding sulfones, and (iii) ther-
mal or base-promoted fragmentation of these sulfones to alk-
enes. The stereochemistry of the starting epoxide is transfer-
red faithfully to the alkene product, because of the SN2 epox-
ide ring-opening reactions and the antiperiplanar SO2 elimi-
nation reaction of the β-alkoxysulfinate intermediates. This
methodology may form the basis of a new protecting group
strategy for alkenes.
Introduction
Protecting group strategies for alkenes are notably lack-
ing from the arsenal of techniques available to synthetic or-
ganic chemists. Neither of the two standard monographs on
protecting groups make any reference to alkene protec-
tion,[1,2] yet alkenes are of course very common functional
groups, and a reliable protecting group strategy for this
functionality may find wide applications in synthesis. Of the
few available reversible modifications of alkenes that might
be used to protect the C=C bond, most suffer the disadvan-
tages of harsh reagents or reaction conditions, or both.
Examples of reversible chemical modifications of alkenes
that have been suggested as protecting group strategies in-
clude the hydroxylation of alkenes to glycols, which may
then be reconverted to alkenes via desulfonation-decarbox-
ylation of cyclic thionocarbonate derivatives;[3] alkene bro-
mination followed by debromination with zinc;[4] the forma-
tion of episulfides, which can be desulfurized with phos-
phanes, phosphites,[5,6] or thiocyanate;[7–9] and the epoxid-
ation of alkenes, followed by regeneration of the alkene
using a range of reducing agents such as Li,[10] SmI2,[11,12]
Me2PhSiLi,[13] dimethyl diazomalonate/Rh2OAc4,[14] and
ZrCl4/NaI.[15]
Scheme 1. The modified Julia (Julia–Kocienski) olefination reac-
tion.
We reasoned that the alkoxide intermediate 2 might be
accessed directly by the reaction of an epoxide 8 with
benzothiazole-2-sulfinate 7. This would then lead to the for-
mation of the alkene 6 (Scheme 2). Consideration of the
expected anti elimination of SO2 from intermediate 4 sug-
gested that cis epoxides would lead to Z-alkenes and that
trans epoxides would lead to E-alkenes. Herein, we report
our studies of the stereospecific formation of alkenes from
mono-, di-, and trisubstituted epoxides.
In searching for a mild and convenient method for the
deoxygenation of epoxides,[16] we considered the proposed
mechanism of the modified Julia olefination,[17,18] in which
a metallated benzothiazole sulfone 1 reacts with a carbonyl
compound to give an intermediate alkoxide 2 that un- Scheme 2. Proposed reaction of benzothiazole-2-sulfinate with ep-
oxides to form alkenes.
dergoes a Smiles-type rearrangement via 3, leading to frag-
mentation with loss of SO2 from 4 to give alkene 6 and the
benzothiazol-2-olate heterocycle 5 (Scheme 1).
Results and Discussion
[a] The University of Queensland, School of Chemistry and Molec-
ular Biosciences,
At the outset of the studies, we required the sulfinate salt
7. The synthesis of this compound from readily available 2-
mercaptobenzothiazole 9 has been reported by Okai and
co-workers,[19] but it was characterized only by an infrared
Brisbane, Qld 4072, Australia
Fax: +61-7-3346-3249
E-mail: r.mcgeary@uq.edu.au
[b] The University of Queensland, School of Pharmacy,
Brisbane, Qld 4072, Australia
Eur. J. Org. Chem. 2010, 1989–1998
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1989

F.-L. Wu, B. P. Ross, R. P. McGeary
FULL PAPER
spectrum. In our hands, attempted preparation of 7 by the tion conditions in which the expected product was iden-
method of Okai and co-workers gave only a mixture of the tified, the reactions were repeated on a preparative scale
sulfonic acid 10 and benzothiazole 11 (Scheme 3). In no and isolated yields were determined (Table 1).
trials were we able to identify the desired sulfinic acid 7 in
Table 1. Reaction conditions and yields for the formation of alkene
16 from sulfone 15.
the NMR spectra of the crude reaction product.
Scheme 3. Attempted synthesis of sulfinate salt 7 from 2-mercapto-
benzothiazole 9.
Entry Base[a]
Solvent[b] Temp.
r.t.
Time [h]
% Yield
(GC-MS) (isolated)
% Yield
In light of our inability to obtain the sulfinate salt 7, we
modified our strategy and decided to react our epoxides 8
with the thiolate derived from 2-mercaptobenzothiazole 9,
followed by oxidation of the resulting thioether 12 to the
corresponding sulfone, thus obtaining 2 in two steps rather
than one (Scheme 4).
1
NaOMe MeOH
7.5
7.5
7.5
17
4
72
25
23
21
21
21
90
22
78
86
93
92
80
80
–
–
–
–
–
71
75
86
89
80
80
–
–
–
–
–
2
3
4
5
6
7
K2CO3
DBU
DBU
DBU
Et3N[c]
Et3N
MeOH
MeOH
THF
r.t.
r.t.
r.t.
CH2Cl2 r.t.
MeOH
THF
r.t.
reflux
8
Et3N
CH2Cl2 reflux
9
pyridine MeOH
pyridine THF
pyridine CH2Cl2 reflux
TFA
–
reflux
reflux
10
11
12
13
CH2Cl2 reflux
toluene reflux
–
82
–
82
[a] Two molar equivalents of base were used. [b] MeOH and THF
were dried with molecular sieves (3 Å). [c] Four molar equivalents
were used.
Scheme 4. Alternative preparation of sulfone 2 by oxidation of
thioether 12.
As a test substrate, we used the epoxide 13 derived from
methyl undec-10-enoate to screen a range of reaction condi-
tions for its ring-opening with 2-mercaptobenzothiazole 9
and subsequent oxidation-elimination reactions. The best
conditions found for the ring-opening of the epoxide 13
with 9 were a catalytic amount of sodium methoxide in re-
fluxing methanol solution, giving the thioether 14 in 74%
yield. When one molar equivalent of sodium methoxide was
employed, side-products arising from solvolysis of the epox-
ide were isolated, as was the episulfide corresponding to 13.
Oxidation of the thioether 14 to the sulfone 15 was achieved
with either mCPBA in dichloromethane or, better, buffered
Oxone® in refluxing aqueous acetone (76% yield)
(Scheme 5).
Several conclusions can be drawn from the results pre-
sented in Table 1. The weak base pyridine was ineffective in
promoting the fragmentation of 15 (Entries 9–11). Triethyl-
amine was also unable to promote the fragmentation in
THF or dichloromethane, but worked well in methanol, al-
beit slowly at room temperature (Entry 6). The stronger
bases DBU, potassium carbonate, and sodium methoxide
were all capable of promoting the formation of the alkene
16 from the sulfone 15 in good yields at room temperature
(Entries 1–5). As a control, the reaction was attempted in
the presence of acid (Entry 12) but this proved ineffective.
Interestingly, performing the reaction in refluxing toluene
in the absence of base also led to the formation of the de-
sired alkene in good yield (Entry 13).
Having established that a number of bases and solvents
were suitable for fragmenting the sulfone 15 to the alkene
16 at room temperature, we then proceeded to examine the
scope of this reaction by extending it to epoxides derived
from di- and tri-substituted alkenes. The 1,1-disubstituted
alkene 17 and the Z-alkenes 18 and 19 were selected, as well
as the trisubstituted alkene 20 and the diene 21 (Figure 1).
Scheme 5. Preparation of alkene 16 from epoxide 13 via thioether
14 and sulfone 15.
With the sulfone 15 in hand, we next investigated its reac-
tion in a range of solvents, bases, and temperatures. Product
yields were determined initially by GC–MS. For those reac- Figure 1. Di- and trisubstituted alkenes 17–21.
1990 Eur. J. Org. Chem. 2010, 1989–1998
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

New Methodology for the Conversion of Epoxides to Alkenes
While the conversion of alkenes 17–21 to their corre-
sponding epoxides 22–26 (Figure 2) could generally be ac-
complished either with mCPBA in dichloromethane or
Oxone® in aqueous acetone, the latter method gave some
unexpected results in the case of alkenes 17 and 19.
Scheme 8. Proposed mechanism for formation of episulfide 29 from
epoxide 24 and 2-mercaptobenzothiazole 9.
Figure 2. Di- and trisubstituted epoxides 22–26.
We eventually found that the use of hot, neat triethyl-
amine as a base was effective for promoting the ring-open-
ing of epoxides 22–26 with 9 in good yields (Table 2). In
some cases, the addition of boron trifluoride improved the
reaction yields (Table 2, Entries 1 & 3). As expected, nucleo-
philic attack of 9 occurred at the least hindered end of the
epoxides 22, 25, and 26, and no regioselectivity was ob-
served for the ring-opening of epoxide 23, which gave the
β-hydroxy thioether isomers 31 and 32 in equal amounts.
Attempted epoxidation of alkene 17 using buffered
Oxone® in aqueous acetone for several days did not give the
expected epoxide 22, but rather the corresponding glycol 27
in 93% yield. When the reaction was repeated with a reac-
tion time of only 3 h, the desired epoxide 22 was obtained
in 97% yield. Epoxidation of 17 with mCPBA in dichloro-
methane also proceeded uneventfully, to give 22 in 72%
yield (Scheme 6).
Table 2. Reaction conditions and yields for the formation of β-hy-
droxy thioethers by ring-opening of epoxides.
Entry Epoxide Product Reaction conditions
Time [h]
% Yield
1
2
3
4
5
22
23
24
25
26
30
Et3N, BF3·OEt2, ∆
18
3.5
6
48
18
84
86
87
58
87
31 & 32 Et3N, ∆
33
34
35
Et3N, BF3·OEt2, ∆
Et3N, ∆
Et3N, ∆
Scheme 6. Preparation of glycol 27 and epoxide 22 from alkene 17.
Another unexpected reaction was observed when epoxid-
ation of the dibenzyl ether 19 was attempted using buffered
Oxone® in aqueous acetone. Instead of the expected epox-
ide 24 forming, the product was the epoxide 28, in which
one of the benzyl protecting groups had been removed.[20,21]
Again mCPBA in dichloromethane proved effective for the
epoxidation of 19, giving 24 in 88% yield (Scheme 7).
Oxidation of the thioethers 30–35 (Figure 3) to the corre-
sponding sulfones 36–41 was achieved in good yields using
Oxone® in cold, buffered aqueous acetone (Table 3). For
thioether 35, the alkene group was also oxidized under
these conditions to the sulfone-epoxide 41 (Figure 4). Use
of the conditions previously employed to oxidize thioether
14 to sulfone 15 (refluxing solvent) or the use of mCPBA
in dichloromethane led only to the isolation of the alkenes
derived from fragmentations of the intermediate sulfones
36–41, suggesting that these sulfones were much more ther-
mally labile than 15. This was confirmed for sulfones 37–
41, which proved to be unstable to storage at room tem-
perature or towards chromatography on silica gel. Never-
theless these compounds were all obtained in good yields
and in sufficient purities for subsequent steps.
Scheme 7. Epoxidation of alkene 19 to give 24, and Oxone®-medi-
ated debenzylation to give 28.
With the sulfones 36–41 in hand we were able to confirm
Ring-opening of di- and tri-substituted epoxides 22–26 their facile conversion to the alkenes 17–20 and 43, in good
with 2-mercaptobenzothiazole proved to be more difficult yields, by treatment with DBU at room temperature in
than was the case for 13. The use of sodium methoxide in either methanol or dichloromethane solution (Table 4).
methanol generally proved to be ineffective in promoting Alkenes 18 and 19 could also be obtained in equivalent
the ring opening of these epoxides. In most cases no reac- yields, by heating them in toluene solution (Entries 3 and
tion occurred, but for epoxide 24, the product isolated was 5). In the case of alkene 17 (Entry 1) the volatility of this
¸
the episulfide 29, in 44% yield, which presumably formed compound precluded an accurate determination of the yield
via the intermediates shown in Scheme 8.[22]
of this reaction, and so 17 was converted in situ to its corre-
Eur. J. Org. Chem. 2010, 1989–1998
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
1991

F.-L. Wu, B. P. Ross, R. P. McGeary
FULL PAPER
Table 4. Reaction conditions and yields for the formation of
alkenes from sulfones.
Entry Sulfone
Alkene
Solvent
Base
Time [h] % Yield
1
2
3
4
5
6
7
36
17
18
18
19
19
20
43
MeOH
MeOH
DBU
DBU
–
DBU
–
17
1
3
3
3
68[a]
83
83
80
80
62
70
37 & 38
37 & 38
39
39
40
toluene, ∆
MeOH
toluene, ∆
CH2Cl2
CH2Cl2
DBU
DBU
2
3
41
[a] Isolated as the dibromide.
Figure 3. β-Hydroxy thioethers 30–35.
Table 3. Reaction conditions and yields for the formation of
sulfones from thioethers.
Scheme 9. Preparation of the dibromide 42 from the volatile alkene
17.
Fragmentation of sulfone 41 gave the monoepoxide 43
(Scheme 10). Alkenes 18 and 19 were obtained exclusively
as the Z-isomers, confirming the stereochemical integrity of
both the ring-opening reactions of the epoxides 23 and 24,
and the subsequent antiperiplanar fragmentation reaction
of the β-alkoxysulfinates (cf. 4 in Scheme 1). Thus, this
methodology preserves the stereochemistry of the alkenes
through the epoxidation and deoxygenation steps.
Entry
Thioether
Sulfone
Time [h]
% Yield
1
2
3
4
5
30
31 & 32
33
34
35
36
37 & 38
39
40
41
20
24
10
48
72
73
80
81
91
96
Scheme 10. Preparation of the monoepoxide 43 from the sulfone
41.
Conclusions
New methodology has been developed for the stereospec-
ific conversion of epoxides into alkenes. Base-promoted
ring-opening of mono-, di-, and trisubstituted epoxides
with 2-mercaptobenzothiazole has been demonstrated, fol-
lowed by oxidation of the resulting thioethers to their corre-
sponding sulfones. These (often unstable) sulfones undergo
facile fragmentation to alkenes, 2-hydroxybenzothiazole,
and sulfur dioxide on treatment with base at room tempera-
ture, or in hot toluene without base. The alkene products
are obtained in good yield.
Figure 4. β-Hydroxy sulfones 36–41.
Experimental Section
General Methods: 1H and 13C NMR spectra were recorded on
Bruker AV500, AV400, or AV300 spectrometers in CDCl3. NMR
spectroscopic data for thermally unstable sulfones 36–41 were ac-
sponding dibromide 42 by treatment with elemental bro-
mine and a catalytic amount of pyridine (Scheme 9). The
dibromide 42 was then isolated in 68% yield for the two
steps.
1992
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New Methodology for the Conversion of Epoxides to Alkenes
quired at 5 °C, and rotary evaporations of solutions of these sul-
fones were performed at 0 °C. MeOH and THF were dried with
molecular sieves (3 Å). Low resolution mass spectrometry was per-
formed on a Finnigan AP1–3 sprayer mass spectrometer in positive
electrospray ionization mode. High resolution electrospray ioniza-
tion accurate mass measurements were recorded in positive and
negative mode on a Bruker MicroTOF-Q instrument with a Bruker
yellow solid (3.91 g, 76%); m.p. 62–65 °C. Rf = 0.27 (n-hexan/
EtOAc = 4:1). H NMR (500 MHz, CDCl3): δ = 1.19–1.42 (m, 10
1
H, 4,5,6,7,8-H), 1.45–1.62 (m, 4 H, 3,9-H), 2.26 (t, J = 5.2 Hz, 2
H, 2-H), 3.60–3.62 (m, 5 H, 11-H, CH3), 4.29–4.39 (m, 1 H, 10-
H), 7.56–7.63 (m, 2 H, arom. CH), 7.98–8.02 (m, 1 H, arom. CH),
8.16–8.18 (m, 1 H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3):
δ = 24.8 (C-3), 24.9 (C-4), 28.9 (C-5), 29.0 (C-6), 29.1 (C-7), 29.2
ESI source. Accurate mass measurements were carried out with (C-8), 34.0 (C-2), 36.3 (C-9), 51.4 (CH3), 61.4 (C-11), 66.0 (C-10),
external calibration using sodium formate as reference calibrant
and/or Agilent tune mix. Melting points were measured with a cap-
illary apparatus and are uncorrected. Thin layer chromatography
(TLC) was performed on silica gel 60 F254 aluminium sheets.
122.4, 125.4, 127.7, 128.1 (arom. C), 136.5, 152.3, 166.3 (arom.
C
ipso), 174.2 (CO) ppm. LRMS: m/z = 436 [M + Na]+. HRMS:
calcd. for C19H27NS2NaO5 436.1228 [M + Na]+; found 436.1238.
Methyl Undec-10-enoate (16): To a suspension of undec-10-enoic
acid, zinc salt (10.0 g, 23.2 mmol) in MeOH (200 mL) under argon
was added concd. H2SO4 (6 mL). The mixture was stirred and
heated under reflux for 4 h. The solvent was removed under vac-
uum and the residue was taken up in Et2O (200 mL). The solution
was washed with saturated aqueous NaHCO3 solution
(3ϫ200 mL), water (3ϫ200 mL), and brine (150 mL), then dried
(MgSO4) and the solvents evaporated. The residual oil was purified
by silica flash column chromatography (petroleum ether/EtOAc =
19:1) to give the methyl ester 16[24] (8.48 g, 92%) as a colorless oil.
Methyl 9-(Oxiran-2-yl)nonanoate (13): To a suspension of methyl
undec-10-enoate (16, 3.23 g, 16.3 mmol) and NaHCO3 (8.65 g,
103 mmol) in acetone (60 mL) at 0 °C was added a solution of
Oxone® (15.2 g, 24.5 mmol) in water (60 mL) cautiously and por-
tionwise over a period of 30 min. The mixture was stirred and
warm to room temperature for 11 h. The reaction mixture was ex-
tracted with Et2O (2ϫ60 mL), washed with water (60 mL), then
dried (MgSO4) and evaporated to give the oxirane 13[23] (2.77 g,
79%) as a pale yellow oil. Rf = 0.54 (n-hexan/EtOAc = 6:4). 1H
NMR (500 MHz, CDCl3): δ = 1.27 (br. s, 8 H, 4,5,6,7-H), 1.36– Rf = 0.33 (petroleum ether/EtOAc = 19:1). 1H NMR (300 MHz,
1.45 (m, 2 H, 8-H), 1.47–1.51 (m, 2 H, 9-H), 1.54–1.62 (m, 2 H, 3- CDCl3): δ = 1.26–1.36 (br. s, 10 H, 4,5,6,7,8-H), 1.54–1.61 (m, 2
H), 2.27 (t, J = 7.5 Hz, 2 H, 2-H), 2.43 (dd, J = 4.9, 2.7 Hz, 1 H,
11-Ha), 2.71 (t, J = 4.6 Hz, 1 H, 11-Hb), 2.85–2.88 (m, 1 H, 10-H), 3.63 (s, 3 H, CH3), 4.88–4.92 (m, 1 H, 11-Ha), 4.92–4.99 (m, 1 H,
3.63 (s, 3 H, CH3) ppm. 13C NMR (125 MHz, CDCl3): δ = 24.8 11-Hb), 5.17–5.84 (m, 1 H, 10-H) ppm. 13C NMR (75 MHz,
(C-3), 25.9 (C-8), 29.0 (C-4), 29.1 (C-5), 29.2 (C-6), 29.3 (C-7), 32.4 CDCl3): δ = 24.9 (C-3), 28.8 (C-4), 29.0 (C-5), 29.1 9 (C-6), 29.16
H, 3-H), 1.96–2.04 (m, 2 H, 9-H), 2.27 (t, J = 7.4 Hz, 2 H, 2-H),
(C-9), 34.0 (C-2), 47.0 (C-11), 51.4 (C-10), 52.3 (CH3), 174.2 (CO)
(C-7), 29.24 (C-8), 33.7 (C-2), 34.0 (C-9), 51.3 (CH3), 114.1 (C-
11), 139.1 (C-10), 174.2 (CO) ppm. HRMS: calcd. for C12H22O2
198.1618 [M]+; found 198.1621. C12H22O2 (198.30): calcd. C 72.68,
H 11.18; found C 72.80, H 11.38.
ppm. LRMS: m/z
= 237 [M +
Na]+. HRMS: calcd. for
C12H22NaO3 237.1467 [M + Na]+; found 237.1466. C12H22O3
(214.30): calcd. C 67.26, H 10.35; found C 66.87, H 10.31.
Methyl 11-(Benzo[d]thiazol-2-ylthio)-10-hydroxyundecanoate (14):
To a solution of sodium (12.8 mg, 0.56 mmol) in dry MeOH
(10 mL) at 0 °C under argon was added 2-mercaptobenzothiazole
(9, 936 mg, 5.60 mmol). Methyl 9-(oxiran-2-yl)nonanoate (13,
1.2 g, 5.60 mmol) in MeOH (5 mL) was added to the stirred mix-
ture which was then heated under reflux overnight. Saturated aque-
ous NH4Cl solution (50 mL) was added before removing the
MeOH in vacuo. The remaining aqueous layer was extracted with
2-Butyl-1-hexene (17): Triphenylphosphane (10.4 g) was recrys-
tallized from EtOH and dried in vacuo for 8 h. The recrystallized
triphenylphosphane (9.34 g, 35.6 mmol) and iodomethane (5.40 g,
38.0 mmol) in benzene (35 mL) were stirred at room temperature
overnight. The precipitate was filtered off and dried with P2O5 un-
der high vacuum for 8 h to give the phosphonium salt in 89% yield
(12.8 g). nBuLi (5 mL; 2.0  solution in cyclohexane) was added
dropwise to an ice-cold solution of methyltriphenylphosphonium
CH2Cl2 (3ϫ150 mL). The combined extracts were dried (MgSO4) iodide (5.68 g, 14.1 mmol) in dry THF (20 mL) under argon. 5-
and evaporated, then the residual oil was purified by silica flash
column chromatography (n-hexan/EtOAc = 3:1) to afford the thio-
ether 14 (1.55 g, 73%) as a yellow oil. Rf = 0.33 (n-hexan/EtOAc
Nonanone (1.0 g, 7.1 mmol) in dry THF (30 mL) was added drop-
wise to the stirred ylide (red-orange) via syringe. The reaction mix-
ture was stirred and warm to room temperature for 2 d. Petroleum
= 7:3). 1H NMR (400 MHz, CDCl3): δ = 1.26–1.49 (br. s, 10 H, ether (100 mL) was added to the mixture and the supernatant solu-
4,5,6,7,8-H), 1.51–1.66 (m, 4 H, 3,9-H), 2.26 (t, J = 7.6 Hz, 2 H,
2-H), 3.30 (dd, J = 14.2, 7.2 Hz, 1 H, 11-Ha), 3.51 (dd, J = 14.2,
tion was decanted and filtered. The filtrate was washed with water
(3ϫ50 mL) and dried (Na2SO4). Evaporation of the solvent gave
3.0 Hz, 1 H, 11-Hb), 3.62 (s, 3 H, CH3), 3.95–4.03 (m, 1 H, 10-H), a residue which was purified by silica flash column chromatography
7.25 (td, J = 8.1, 1.2 Hz, 1 H, arom. CH), 7.36 (td, J = 7.2, 1.2 Hz,
(petroleum ether) to give the alkene 17[25] (683 mg, 69%) as a color-
1
1 H, arom. CH), 7.69 (d, J = 7.8 Hz, 1 H, arom. CH), 7.79 (d, J less oil. Rf = 0.74 (petroleum ether). H NMR (400 MHz, CDCl3):
= 7.4 Hz, 1 H, arom. CH) ppm. 13C NMR (100 MHz, CDCl3): δ δ = 0.9 (t, J = 7.1 Hz, 6 H, 2 x CH3), 1.26–1.44 (m, 8 H, 4ϫ CH2),
= 24.8 (C-3), 25.5 (C-4), 29.0 (C-5), 29.1 (C-6), 29.2 (C-7), 29.4 (C-
8), 34.0 (C-2), 36.5 (C-9), 40.9 (C-11), 51.4 (CH3), 71.2 (C-10),
120.9, 121.1, 124.6, 126.2 (arom. C), 135.0, 151.9, 168.1 (arom.
Cipso), 174.3 (CO) ppm. LRMS: m/z = 404 [M + Na]+. HRMS:
calcd. for C19H27NS2NaO3 404.1334 [M + Na]+; found 404.1334.
2.00 (t, J = 7.2 Hz, 4 H, 2ϫ CH2), 4.69 (quintet, J = 1.1 Hz, 2 H,
CH2) ppm. LRMS: m/z = 140 [M]+.
Methyl Oleate (18): To a solution of oleic acid (5.06 g, 17.9 mmol)
in dry MeOH (20 mL) was added concd. H2SO4 (5 drops). The
reaction mixture was heated under reflux for 1 d. The solvent was
Methyl
11-(Benzo[d]thiazol-2-ylsulfonyl)-10-hydroxyundecanoate removed in vacuo and the residue was taken up in Et2O
(15): To a solution of 14 (4.74 mg, 12.4 mmol) and NaHCO3
(2ϫ50 mL), washed with saturated aqueous NaHCO3 solution
(6.66 g, 79.4 mmol) in acetone (250 mL) and water (125 mL) was (2ϫ50 mL), water (3ϫ50 mL) and brine (2ϫ50 mL), then dried
added Oxone® (24.6 g, 39.7 mmol) cautiously and portionwise. The
mixture reaction was heated under reflux for 3 h. It was then ex-
tracted with Et2O (3ϫ100 mL), washed with water (2ϫ80 mL),
dried (Na2SO4) and evaporated to give the sulfone 15 as a pale
(Na2SO4). Evaporation of the solvent gave a residue which was
purified by silica flash column chromatography (petroleum ether/
EtOAc = 19:1) to afford the methyl ester 18[26] (4.93 g, 93%) as a
pale orange oil. Rf = 0.44 (petroleum ether/EtOAc = 19:1). 1H
Eur. J. Org. Chem. 2010, 1989–1998
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
1993

F.-L. Wu, B. P. Ross, R. P. McGeary
NMR (500 MHz, CDCl3): δ = 0.86 (t, J = 6.8 Hz, 3 H, CH3), 1.25– stroyed by carefully adding water (20 mL) and then the THF was
FULL PAPER
1.29 (m, 20 H, 5ϫ CH2), 1.58–1.63 (m, 2 H, CH2), 1.96–2.04 (m,
4 H, 2ϫ CH2), 2.29 (t, J = 7.4 Hz, 2 H, CH2), 3.62 (s, 3 H, CH3),
removed in vacuo. Another 50 mL of water was added and the
mixture was acidified with HCl (5%), extracted with CH2Cl2
5.28–5.32 (m, 2 H, CH) ppm. 13C NMR (125 MHz, CDCl3): δ = (3ϫ100 mL), washed with water (60 mL) and brine (60 mL), then
14.0 (CH3), 22.6, 24.9, 27.1, 27.2, 29.0, 29.11, 29.14, 29.3, 29.5,
29.6, 29.7, 31.8, 34.0 (CH2), 51.4 (CH3), 129.7, 129.9 (CH), 174.2
(CO) ppm.
dried (MgSO4). Evaporation of the solvent gave a residue which
was purified by silica flash column chromatography (petroleum
ether/EtOAc = 17:3) to afford the benzyl ether 21[29] (3.91 g, 92%)
as a colorless oil. Rf = 0.75 (petroleum ether/EtOAc = 17:3). 1H
NMR (500 MHz, CDCl3): δ = 1.61 (s, 3 H, CH3), 1.65 (s, 3 H,
CH3), 1.69 (s, 3 H, CH3), 2.04–2.07 (m, 2 H, CH2), 2.10–2.13 (m,
2 H, CH2), 4.04 (d, J = 6.7 Hz, 2 H, CH2), 4.51 (s, 2 H, CH2), 5.11
(t, J = 6.7 Hz, 1 H, CH), 5.41 (t, J = 6.7 Hz, 1 H, CH), 7.27–7.39
(m, 5 H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ = 16.4,
17.6, 25.6 (CH3), 26.3, 39.5, 66.5, 71.9 (CH2), 120.8, 123.9, 127.4,
(Z)-1,4-Bis(benzyloxy)but-2-ene (19): To a solution of (Z)-butene-
1,4-diol (2.76 g, 30.8 mmol) in dry THF (50 mL) was added NaH
(60% dispersion in mineral oil; 3.37 g, 135 mmol) under argon. The
reaction mixture was heated under reflux for 2 h and cooled to
room temperature.
A solution of benzyl bromide (20.7 g,
118 mmol) in dry THF (50 mL) was added dropwise to the stirred
mixture. The reaction mixture was then stirred and heated under
reflux for 1 h, followed by 4 d stirring at room temperature. The
excess NaH was destroyed by careful addition of water (20 mL)
then the THF was removed in vacuo. The residue was taken up in
CH2Cl2 (3ϫ40 mL), washed with saturated aqueous NH4Cl solu-
tion (3ϫ40 mL), water (40 mL) and brine (40 mL), and then dried
(MgSO4). Evaporation of the solvent gave a residue which was
purified by silica flash column chromatography (petroleum ether/
EtOAc = 9:1) to generate the dibenzyl ether 19[27] (8.27 g, 98%) as
a colorless oil. Rf = 0.64 (petroleum ether/EtOAc = 4:1). 1H NMR
(500 MHz, CDCl3): δ = 4.06–4.07 (m, 4 H, 1,4-H), 4.49 (s, 4 H,
2ϫ PhCH2), 5.79–5.81 (m, 2 H, 2ϫ CH), 7.26–7.32 (m, 10 H,
arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ = 65.7 (C-1),
72.2 (C-2), 127.6, 127.7, 128.3, 129.4, 138.1 (CH, arom. C) ppm.
LRMS: m/z = 291 [M + Na]+.
127.8, 128.3 (CH, arom. C), 131.6, 138.5, 140.3 (C, arom. Cipso
ppm.
)
2-Butyl-1,2-epoxyhexane (22): (i) To a solution of mCPBA (1.48 g
as a 77 wt.-% solid, 6.6 mmol) in CH2Cl2 (30 mL) at 0 °C under
argon was added 2-butyl-1-hexene (17, 600 mg, 4.28 mmol). The
reaction mixture was stirred and warm to room temperature over-
night. The mixture was diluted with CH2Cl2 (50 mL), washed with
1  NaOH (3ϫ50 mL) and water (50 mL), and dried (Na2SO4).
Evaporation of the solvent gave the epoxide 22[30] as a colorless oil
(480 mg, 72%). 1H NMR (500 MHz, CDCl3): δ = 0.90 (t, J =
7.0 Hz, 6 H, 2ϫ CH3), 1.29–1.36 (m, 8 H, 4ϫ CH2), 1.47–1.52 (m,
2 H, CH2), 1.57–1.61 (m, 2 H, CH2), 2.56 (s, 2 H, CH2) ppm. 13C
NMR (125 MHz, CDCl3): δ = 13.9 (CH3), 22.8, 27.0, 33.9, 52.5
(CH2), 59.5 (C) ppm.
(ii) To a suspension of 2-butyl-1-hexene (264 mg, 1.89 mmol) and
NaHCO3 (950 mg, 11.3 mmol) in acetone (6 mL) at 0 °C was added
a solution of Oxone® (2.92 g, 4.71 mmol) in water (6 mL) cau-
tiously and portionwise over a period of 30 min. The reaction mix-
ture was stirred and warm to room temperature for 3 h. The mix-
ture was extracted with CH2Cl2 (3ϫ10 mL), washed with water
(15 mL), dried (MgSO4) and evaporated to give 22, identical to that
described above (286 mg, 97%).
5-Ethylidenenonane (20): Triphenylphosphane (11.4 g) was recrys-
tallized from EtOH and dried under vacuum overnight. The recrys-
tallized triphenylphosphane (10.7 g, 40.7 mmol) and iodoethane
(8.26 g, 52.9 mmol) in toluene (40 mL) were heated under reflux
for 36 h. Petroleum ether (100 mL) was added to the reaction mix-
ture. The precipitate was filtered off and washed with more petro-
leum ether. It was then dried with P2O5 under high vacuum for
12 h to afford the phosphonium salt in 70% yield (11.8 g). To a
solution of the phosphonium salt (5.88 g, 14.1 mmol) in dry THF
(30 mL) at 0 °C was added nBuLi (6.5 mL; 2.0  solution in cyclo-
hexane) slowly. The reaction mixture was stirred at 0 °C for 30 min
before adding a solution of 5-nonanone (1.01 g, 7.10 mmol) in dry
THF (13 mL) dropwise. The reaction mixture was stirred and warm
to room temperature for 1 d. Petroleum ether (100 mL) was added,
then the supernatant solution was decanted and filtered. The or-
ganic layer was washed with water (3ϫ60 mL) and dried (Na2SO4).
Evaporation of the solvent gave a residue which was purified by
silica flash column chromatography (petroleum ether) to afford the
alkene 20[28] (504 mg, 42%) as a colorless oil. Rf = 0.83 (petroleum
Methyl 8-(3-Octyloxiran-2-yl)octanoate (23): To a suspension of
methyl oleate (18, 1.09 g, 3.68 mmol) and NaHCO3 (2.31 g,
27.5 mmol) in acetone (40 mL) at 0 °C was added a solution of
Oxone® (5.29 g, 8.54 mmol) in water (40 mL) cautiously and por-
tionwise over a period of 30 min. The reaction mixture was stirred
and warm to room temperature overnight. The mixture was ex-
tracted with CH2Cl2 (3ϫ50 mL), washed with water (50 mL) and
dried (MgSO4). Evaporation of the solvent gave a residue which
was purified by silica flash column chromatography (petroleum
ether/EtOAc = 9:1) to afford the epoxide 23[31] (933 mg, 89%) as a
1
colorless yellow oil. Rf = 0.48 (petroleum ether/EtOAc = 9:1). H
1
ether) H NMR (500 MHz, CDCl3): δ = 0.9 (q, J = 7.1 Hz, 6 H,
NMR (500 MHz, CDCl3): δ = 0.88 (t, J = 6.8 Hz, 3 H, CH3), 1.24–
1.36 (m, 16 H, 8ϫ CH2), 1.47–1.50 (m, 6 H, 3ϫ CH2), 1.55–1.56
(m, 2 H, CH2), 1.60–1.63 (m, 2 H, CH2), 2.30 (t, J = 7.4 Hz, 2 H,
2ϫ CH), 2.87–2.91 (m, 2 H, CH2), 3.66 (s, 3 H, CH3) ppm. 13C
NMR (125 MHz, CDCl3): δ = 14.0 (CH3), 22.6, 24.9, 26.54, 26.59,
27.7, 27.8, 29.0, 29.1, 29.2, 29.3, 29.51, 29.54, 31.8, 34.0, 51.4
(CH3), 57.1, 57.2 (CH), 174.2 (CO) ppm.
CH3), 1.24–1.37 (m, 8 H, 4ϫ CH2), 1.57 (d, J = 6.6 Hz, 3 H, CH3),
1.95 (t, J = 7.2 Hz, 2 H, CH2), 2.00 (t, J = 7.3 Hz, 2 H, CH2), 5.18
(q, J = 6.6 Hz, 1 H, CH) ppm. 13C NMR (125 MHz, CDCl3): δ =
13.1, 14.03, 14.06 (CH3), 22.5, 22.8, 29.4, 30.45, 30.48, 36.7 (CH2),
117.9 (CH), 140.6 (C) ppm.
Benzyl Geranyl Ether (21): To a solution of geraniol (2.7 g,
17.5 mmol) in dry THF (80 mL) was added NaH (60% dispersion
in mineral oil; 1.56 g, 65.0 mmol) under argon. The reaction mix-
ture was stirred at room temperature for 1 h and then heated under
reflux for 30 min. The mixture was allowed to cool to room tem-
perature before adding a solution of benzyl bromide (7.92 g,
62.6 mmol) in dry THF (50 mL) dropwise. A catalytic amount of
tetrabutylammonium iodide was also added. The reaction mixture
was stirred at room temperature for 3 d. The excess NaH was de-
2,3-Bis(benzyloxymethyl)oxirane (24): To a solution of mCPBA
(5.25 g as a 77 wt.-% solid, 23.4 mmol) in CH2Cl2 (30 mL) at 0 °C
was added a solution of (Z)-1,4-bis(benzyloxy)but-2-ene (19,
2.01 g, 7.49 mmol) in CH2Cl2 (30 mL) dropwise. The reaction mix-
ture was stirred and warm to room temperature overnight. The
mixture was diluted with CH2Cl2 (70 mL), washed with 1  NaOH
(3ϫ70 mL), water (70 mL) and dried (MgSO4). Evaporation of the
solvent gave a residue which was purified by silica flash column
1994
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 1989–1998

New Methodology for the Conversion of Epoxides to Alkenes
chromatography (petroleum ether/EtOAc = 17:3) to afford the ep-
mixture was extracted with CH2Cl2 (3ϫ50 mL), washed with water
(50 mL) and dried (MgSO4). Evaporation of the solvent gave a
crude mixture which was purified by silica flash column
chromatography (petroleum ether/EtOAc = 4:1) to give the epoxy
alcohol 28[27] (243 mg, 25%). Rf = 0.11 (petroleum ether/EtOAc =
oxide 24[27] (1.87 g, 88%) as a colorless oil. Rf = 0.46 (petroleum
1
ether/EtOAc = 17:3). H NMR (400 MHz, CDCl3): δ = 3.23–3.25
(m, 2 H, 2ϫ CH), 3.52 (dd, J = 11.3, 6.4 Hz, 2 H, 1,1Ј-Ha), 3.68
(dd, J = 11.3, 3.8 Hz, 2 H, 1,1Ј-Hb), 4.49 (d, J = 11.9 Hz, 2 H,
2,2Ј-Ha), 4.59 (d, J = 11.9 Hz, 2 H, 2,2Ј-Hb), 7.26–7.35 (m, 10 H, 7:3). 1H NMR (300 MHz, CDCl3): δ = 2.37 (br. s, 1 H, OH), 3.16–
arom. CH) ppm. 13C NMR (100 MHz, CDCl3): δ = 54.4 (CH),
3.21 (m, 1 H, CH), 3.24–3.29 (m, 1 H, CH), 3.64 (d, J = 2.6 Hz, 1
H, 1-Ha), 3.66 (d, J = 3.6 Hz, 1 H, 1-Hb), 3.70 (d, J = 5.4 Hz, 2
H, CH2), 4.54 (q, J = 11.8 Hz, 2 H, 2-H), 7.27–7.34 (m, 5 H, arom.
CH) ppm. 13C NMR (75 MHz, CDCl3): δ = 54.7, 55.7 (CH), 60.5,
68.0 (C-1), 73.2 (C-2), 127.7, 127.8, 128.4 (arom. C), 137.7 (arom.
C
ipso) ppm. LRMS: m/z = 307 [M + Na]+. HRMS: calcd. for
C18H20NaO3 307.1305 [M + Na]+; found 307.1307.
67.9, 73.4 (CH2), 127.8, 127.9, 128.4 (arom. C), 137.3 (arom. Cipso
)
2,2-Dibutyl-3-methyloxirane (25): To a solution of mCPBA (1.89 g
as a 77 wt.-% solid, 8.4 mmol) in CH2Cl2 (30 mL) at 0 °C under
argon was added 5-ethylidenenonane (20, 400 mg, 2.59 mmol) por-
tionwise. The reaction mixture was stirred and warm to room tem-
perature for 24 h. The mixture was diluted with CH2Cl2 (50 mL),
washed with 1  NaOH (3ϫ50 mL) and water (50 mL), and then
dried (Na2SO4). Evaporation of the solvent gave a residue which
was purified by silica flash column chromatography (petroleum
ether/EtOAc = 17:3) to afford the epoxide 25[32] (388 mg, 96%) as
a colorless oil. Rf = 0.79 (petroleum ether/EtOAc = 17:3). 1H NMR
(400 MHz, CDCl3): δ = 0.89 (q, J = 7.2 Hz, 6 H, 2ϫ CH3), 1.26
(d, J = 5.4 Hz, 3 H, CH3), 1.21–1.35 (m, 10 H, 5ϫ CH2), 1.46–
1.57 (m, 2 H, CH2), 2.82 (q, J = 5.6 Hz, 1 H, CH) ppm. 13C NMR
(100 MHz, CDCl3): δ = 13.8, 14.0 (CH3), 22.8, 23.0, 26.9, 27.3,
29.5, 34.9 (CH2), 59.0 (C), 63.3 (CH) ppm.
ppm. LRMS: m/z = 217 [M + Na]+.
2,3-Bis(benzyloxymethyl)thiirane (29): Sodium (414 mg, 18.0 mmol)
was dissolved in dry MeOH (50 mL) under argon and 7 mL of this
NaOMe solution was added to a flask equipped with 2-mercapto-
benzothiazole (9, 294 mg, 1.76 mmol). The mixture was stirred at
0 °C for 20 min, followed by addition of a solution of 2,3-bis(ben-
zyloxymethyl)oxirane (24, 0.5 g, 1.76 mmol) in dry MeOH (7 mL)
slowly and dropwise. The reaction mixture was stirred and warm
to room temperature for 23 h, and then heated under reflux for
48 h. The mixture was quenched with saturated aqueous NH4Cl
solution (50 mL) before the MeOH was removed in vacuo. The
aqueous layer was extracted with CH2Cl2 (3ϫ50 mL), washed with
brine (50 mL) and water, and then dried (MgSO4). Evaporation of
the solvent gave a crude mixture, which was purified by silica flash
column chromatography (petroleum ether/EtOAc = 7:3) to give the
episulfide 29[35] (234 mg, 44%). Rf = 0.74 (petroleum ether/EtOAc
(3E)-3-(5-Benzyloxy-3-methylpent-3-enyl)-2,2-dimethyloxirane (26):
To a solution of mCPBA (2.27 g as a 77 wt.-% solid, 10.1 mmol)
in CH2Cl2 (30 mL) at 0 °C under argon was added a solution of
benzyl geranyl ether (21, 3.2 g, 13.1 mmol) in CH2Cl2 (20 mL)
dropwise. The reaction mixture was stirred and warm to room tem-
perature for 3.5 h. The mixture was diluted with CH2Cl2 (50 mL),
washed with 1  NaOH (3ϫ50 mL) and water (50 mL), then dried
(Na2SO4). Evaporation of the solvent gave a crude product, which
was purified by silica flash column chromatography (petroleum
ether/EtOAc = 17:3) to afford the epoxide 26[33] (2.69 g, 79%) as a
yellow oil. Rf = 0.41 (petroleum ether/EtOAc = 17:3). 1H NMR
(400 MHz, CDCl3): δ = 1.26 (s, 3 H, CH3), 1.30 (s, 3 H, CH3),
1.63–1.69 (m, 5 H, CH3, CH2), 2.14–2.22 (m, 2 H, CH2), 2.71 (t, J
= 6.2 Hz, 1 H, CH), 4.03 (d, J = 6.7 Hz, 2 H, CH2), 4.50 (s, 2 H,
CH2), 5.43–5.47 (m, 1 H, CH), 7.26–7.34 (m, 5 H, arom. CH) ppm.
13C NMR (100 MHz, CDCl3): δ = 16.4, 18.6, 24.7 (CH3), 27.1,
36.1 (CH2), 58.2 (C), 63.9 (CH), 66.4, 72.0 (CH2), 121.3 (CH),
127.4, 127.7, 128.2, 138.4, 139.3 (C, arom. C) ppm. LRMS: m/z =
283 [M + Na]+.
1
= 5:1). H NMR (400 MHz, CDCl3): δ = .3.18–3.21 (m, 2 H, 2ϫ
CH), 3.65–3.67 (m, 4 H, 1,1Ј-H), 4.39 (q, J = 11.9 Hz, 4 H, 2,2Ј-
H), 7.27–7.32 (m, 10 H, arom CH) ppm. 13C NMR (100 MHz,
CDCl3): δ = 36.5 (CH), 70.0, 73.1 (CH2), 127.75, 127.77, 128.4
(arom. C), 137.8 (arom. Cipso) ppm. LRMS: m/z = 323 [M +
Na]+. HRMS: calcd. for C18H20SNaO2 323.1082 [M + Na]+; found
323.1076.
5-[(Benzo[d]thiazol-2-ylthio)methyl]nonan-5-ol (30): To a mixture of
9 (465 mg, 2.64 mmol) and Et3N (7.0 g, 69.1 mmol) was added 1,2-
epoxy-2-butylhexane (22, 265 mg, 1.70 mmol) then BF3·OEt2 (20
drops). The reaction mixture was heated at 80 °C overnight.
Dichloromethane (30 mL) was added and the mixture was washed
with saturated aqueous NH4Cl solution (3ϫ30 mL), saturated
aqueous NaHCO3 solution (30 mL) and water (30 mL), then dried
(Na2SO4). Evaporation of the solvent gave a crude semisolid, which
was purified by silica flash column chromatography (petroleum
ether/EtOAc = 9:1) to afford the thioether 30 (459 mg, 84%) as
colorless solids. Rf = 0.63 (petroleum ether/EtOAc = 4:1). 1H NMR
(500 MHz, CDCl3): δ = 0.92 (t, J = 7.1 Hz, 6 H, 2ϫ CH3), 1.30–
1.40 (m, 8 H, 4ϫ CH2), 1.61–1.65 (m, 4 H, 2ϫ CH2), 3.51 (s, 2 H,
CH2), 7.30 (td, J = 7.1, 1.1 Hz, 1 H, arom. CH), 7.41 (td, J = 7.2,
1.1 Hz, 1 H, arom. CH), 7.73 (d, J = 8.0 Hz, 1 H, arom. CH), 7.56
(d, J = 8.0 Hz, 1 H, arom. CH) ppm. 13C NMR (125 MHz,
CDCl3): δ = 14.0 (CH3), 23.2, 25.9, 38.5, 44.1 (CH2), 73.8 (C),
121.00, 121.08, 124.6, 126.3 (arom. C), 135.0, 151.8, 169.0 (arom.
Cipso) ppm. LRMS: m/z = 346 [M + Na]+. HRMS: calcd. for
C17H25NS2NaO 346.1270 [M + Na]+; found 346.1265.
2-Butylhexane-1,2-diol (27): To
a mixture of 17 (100 mg,
0.71 mmol) and NaHCO3 (363 mg, 4.32 mmol) in acetone (7 mL)
at 0 °C was added a solution of Oxone® (1.10 g, 1.77 mmol) in
water (7 mL) slowly and portionwise. The reaction mixture was
stirred and warm to room temperature for 4.5 d. The mixture was
dilute with water (15 mL), extracted with dichloromethane
(3ϫ10 mL), and then dried (Na2SO4). Evaporation of the solvent
gave the diol 27[34] as a colorless oil (106 mg, 93%). Rf = 0.17 (pe-
troleum ether/EtOAc/CH2Cl2 = 14:5:1). 1H NMR (500 MHz,
CDCl3): δ = 0.91 (t, J = 7.0 Hz, 6 H, 2ϫ CH3), 1.21–1.37 (m, 8 H,
4ϫ CH2), 1.40–1.51 (m, 4 H, 2ϫ CH2), 3.45 (s, 2 H, CH2) ppm.
13C NMR (100 MHz, CDCl3): δ = 14.0 (CH3), 23.2, 25.5, 35.5,
68.0 (CH2), 74.8 (C) ppm.
Methyl 10-(Benzo[d]thiazol-2-ylthio)-9-hydroxyoctadecanoate (31)
and Methyl 9-(benzo[d]thiazol-2-ylthio)-10-hydroxyoctadecanoate
(32): To a mixture of 9 (557 mg, 3.33 mmol) and Et3N (246 mg,
2.43 mmol) was added methyl 8-(3-octyloxiran-2-yl)octanoate (23,
[3-(Benzyloxymethyl)oxiranyl]methanol (28): To a solution of 19
(1.35 g, 5.03 mmol) and NaHCO3 (2.58 g, 30.7 mmol) in acetone 670 mg, 2.15 mmol) portionwise. The reaction mixture was heated
(50 mL) at 0 °C was added
a
solution of Oxone® (7.84 g, at 90 °C for 3.5 h. The cooled reaction mixture was diluted with
12.6 mmol) in water (50 mL) slowly and portionwise. The reaction
mixture was stirred and warm to room temperature for 1.5 d. The
CH2Cl2 (50 mL), washed with saturated aqueous NaHCO3 solu-
tion (3ϫ50 mL), water (50 mL) and brine (50 mL), then dried
Eur. J. Org. Chem. 2010, 1989–1998
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
1995

F.-L. Wu, B. P. Ross, R. P. McGeary
FULL PAPER
(Na2SO4). Evaporation of the solvent gave a crude mixture which
was purified by silica flash column chromatography (petroleum
ether/EtOAc = 17:3) to afford the thioethers 31 and 32 (888 mg,
86%) as a yellow semisolid. Rf = 0.50 (petroleum ether/EtOAc =
(286 mg, 2.83 mmol). The mixture was heated at 80 °C for 1 h then
1-benzyloxy-6,7-epoxy-3,7-dimethyl-2-octene
(26,
700 mg,
2.69 mmol) was added. The reaction mixture was stirred at 80 °C
for 20 h. Dichloromethane (50 mL) was added to the mixture and it
was washed with saturated aqueous NaHCO3 solution (3ϫ30 mL),
1
17:3). H NMR (400 MHz, CDCl3): δ = 0.85 (t, J = 7.0 Hz, 6 H,
2ϫ CH3), 1.20–1.43 (m, 32 H, 16ϫ CH2), 1.44–1.65 (m, 16 H, 8ϫ water (30 mL) and brine (30 mL), then dried (Na2SO4). Evapora-
CH2), 1.84–1.91 (m, 4 H, 2ϫ CH2), 2.27 (m, 4 H, 2ϫ CH2), 3.64 tion of the solvent gave a crude liquid which was purified by silica
(s, 3 H, CH3), 3.65 (s, 3 H, CH3), 3.83–3.87 (m, 2 H, 2ϫ CH),
4.06–4.13 (m, 2 H, 2ϫ CH), 7.30 (td, J = 7.6, 1.1 Hz, 2 H, arom.
CH), 7.41 (td, J = 7.7, 1.2 Hz, 2 H, arom. CH), 7.74 (d, J = 7.6 Hz,
2 H, arom. CH), 7.84 (d, J = 8.4 Hz, 2 H, arom. CH) ppm. 13C
flash column chromatography (petroleum ether/EtOAc = 4:1) to
afford the thioether 35 (997 mg, 87%) as a yellow wax. Rf = 0.38
1
(petroleum ether/EtOAc = 4:1). H NMR (500 MHz, CDCl3): δ =
1.32 (s, 3 H, CH3), 1.46 (s, 3 H, CH3), 1.63 (s, 3 H, CH3), 1.66–
NMR (100 MHz, CDCl3): δ = 13.96, 13.97 (CH3), 22.50, 22.52, 1.75 (m, 1 H, 1-Ha), 2.04–2.08 (m, 1 H, 1-Hb), 2.22–2.28 (m, 2-Ha),
24.73, 24.77, 25.7, 25.8, 27.2, 27.3, 28.87, 28.89, 28.92, 28.96, 29.06,
29.12, 29.17, 29.25, 29.28, 29.4, 29.5, 31.70, 31.73, 33.91, 33.94,
36.07, 36.09 (CH2), 51.3 (CH3), 56.4, 56.5, 73.4, 73.5 (CH), 120.8,
121.2, 124.4, 126.0 (arom. C), 135.4, 152.5, 166.41, 166.44 (arom.
2.38–2.43 (m, 1 H, 2-Hb), 3.72 (dd, J = 11.6, 2.1 Hz, 1 H, CH),
3.93–4.01 (m, 2 H, CH2), 4.43 (s, 2 H, CH2), 5.40 (td, J = 6.7,
1.1 Hz, 1 H, CH), 7.25–7.43 (m, 6 H, arom. CH), 7.39 (td, J = 8.2,
1.2 Hz, 1 H, arom. CH), 7.71 (d, J = 8.1 Hz, 1 H, arom. CH), 7.82
Cipso), 174.13, 174.17 (CO) ppm. LRMS: m/z = 502 [M + Na]+. (d, J = 8.1 Hz, 1 H, arom. CH) ppm. 13C NMR (125 MHz,
HRMS: calcd. for C26H41NS2NaO3 502.2420 [M + Na]+; found
502.2419.
CDCl3): δ = 16.3, 26.0 (CH3), 28.2 (CH2), 29.2 (CH3), 37.7 (CH2),
61.9 (CH), 66.4, 72.0 (CH2), 72.9 (C), 120.9, 121.1, 122.2, 124.6,
126.2, 127.5, 127.7, 128.3 (CH, arom. C), 135.1, 138.3, 138.7, 152.1,
168.3 (arom. Cipso) ppm. LRMS: m/z = 450 [M + Na]+. HRMS:
calcd. for C24H29NS2NaO2 450.1532 [M + Na]+; found 450.1539.
3-(Benzo[d]thiazol-2-ylthio)-1,4-bis(benzyloxy)butan-2-ol (33): To a
mixture of 9 (1.69 g, 10.1 mmol) and Et3N (26.2 g, 259 mmol) was
added 2,3-bis(benzyloxymethyl)oxirane (24, 1.87 g, 6.56 mmol)
then BF3·OEt2 (18 drops). The reaction mixture was heated at
90 °C for 6 h. Dichloromethane (60 mL) was added to the cooled
mixture and it was washed with saturated aqueous NaHCO3 solu-
tion (3ϫ60 mL) and water (60 mL), then dried (Na2SO4). Evapo-
ration of the solvent gave a crude oil which was purified by silica
flash column chromatography (petroleum ether/EtOAc = 3:2) to
afford the thioether 33 (2.58 g, 87%) as colorless oil. Rf = 0.43
5-[(Benzo[d]thiazol-2-ylsulfonyl)methyl]nonan-5-ol (36): To a solu-
tion of 2-(benzo[d]thiazole-2-ylthio)methyl)nonan-5-ol (30, 78 mg,
0.24 mmol) and NaHCO3 (205 mg, 2.44 mmol) in acetone (10 mL)
at 0 °C was added a mixture of Oxone® (751 mg, 1.21 mmol) in
water (5 mL) cautiously and portionwise. The reaction mixture was
stirred at 0 °C for 20 h. The mixture was diluted with cold water
(10 mL), extracted with cold Et2O (5ϫ20 mL) and dried (Na2SO4).
Removal of the solvent gave the unstable sulfone 36 as a colorless
solid (81.1 mg, 95%). Rf = 0.43 (petroleum ether/EtOAc = 4:1). 1H
NMR (500 MHz, CDCl3): δ = 0.85 (t, J = 7.0 Hz, 6 H, 2ϫ CH3),
1.24–1.30 (m, 8 H, 4ϫ CH2), 1.69–1.72 (m, 4 H, 2ϫ CH2), 3.77
(s, 2 H, CH2), 7.58–7.66 (m, 2 H, arom. CH), 8.01–8.03 (m, 1 H,
arom. CH), 8.20–8.22 (m, 1 H, arom. CH) ppm. 13C NMR
(125 MHz, CDCl3): δ = 13.9 (CH3), 22.9, 25.6, 38.9, 62.0 (CH2),
74.3 (C), 122.3, 125.4, 127.7, 128.1 (arom. C), 136.6, 152.4, 167.2
(arom. Cipso) ppm. LRMS: m/z = 378 [M + Na]+. HRMS: calcd.
for C17H25NS2NaO3 378.1168 [M + Na]+; found 378.1176.
1
(petroleum ether/EtOAc = 3:2). H NMR (500 MHz, CDCl3): δ =
3.69 (d, J = 6.1 Hz, 2 H, CH2), 3.97 (dd, J = 5.6, 3.0 Hz, 2 H,
CH2), 4.38–4.43 (m, 2 H, 2ϫ CH), 4.49–4.61 (m, 4 H, CH2), 7.23–
7.32 (m, 11 H, arom. CH), 7.41 (td, J = 7.7, 1.3 Hz, 1H. arom.
CH), 7.74 (d, J = 8.1 Hz, 1 H, arom. CH), 7.82 (d, J = 8.0 Hz, 1
H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ = 51.0, 70.5,
70.8, 72.0, 73.35, 73.39 (CH, CH2), 120.8, 121.3, 124.3, 126.0,
127.5, 127.6, 127.7, 128.2, 128.3 (arom. C), 135.4, 137.5, 137.8,
152.6, 166.1 (arom. Cipso) ppm. LRMS: m/z = 474 [M + Na]+.
HRMS: calcd. for C25H25NS2NaO3 474.1168 [M + Na]+; found
474.1180.
5-[1-(Benzo[d]thiazol-2-ylthio)ethyl]nonan-5-ol (34): To a mixture of
9 (312 mg, 1.87 mmol) and Et3N (172 mg, 1.70 mmol) was slowly
added 2,2-dibutyl-3-methyloxirane (25, 265 mg, 1.56 mmol). The
reaction mixture was heated to 80 °C for 2 d. Dichloromethane
(30 mL) was added to the cooled mixture and it was washed with
saturated aqueous NaHCO3 solution (3ϫ20 mL), water (20 mL)
and brine (20 mL), then dried (Na2SO4). Evaporation of the sol-
vent gave a crude liquid which was purified by silica flash column
chromatography (petroleum ether/EtOAc = 9:1) to afford the thio-
ether 34 (302 mg, 58%) as a colorless oil. Rf = 0.43 (petroleum
ether/EtOAc = 9:1). 1H NMR (500 MHz, CDCl3): δ = 0.90–0.94
(m, 6 H, 2ϫ CH3), 1.30–1.48 (m, 10 H, 5ϫ CH2), 1.53 (d, J =
7.1 Hz, 3 H, CH3), 1.65–1.71 (m, 2 H, CH2), 1.72–1.79 (m, 1 H,
OH), 4.02 (q, J = 7.2 Hz, 1 H, CH), 7.29 (td, J = 7.3, 1.3 Hz, 1 H,
arom. CH), 7.40 (td, J = 7.2, 1.2 Hz, 1 H, arom. CH), 7.73 (dt, J
= 8.2, 0.7 Hz, 1 H, arom. CH), 7.86 (dt, J = 7.9, 0.8 Hz, 1 H, arom.
CH) ppm. 13C NMR (125 MHz, CDCl3): δ = 14.1, 16.8 (CH3),
23.2, 23.4, 25.6, 25.7, 36.0, 37.6 (CH2), 54.0 (CH), 75.8 (C), 120.9,
Methyl
10-(Benzo[d]thiazol-2-ylsulfonyl)-9-hydroxyoctadecanoate
(37) and Methyl 9-(Benzo[d]thiazol-2-ylsulfonyl)-10-hydroxyoctade-
canoate (38): To a solution of methyl 4-(benzo[d]thiazole-2-ylthio)-
4-hydroxyhexanoate (31) and methyl 3-(benzo[d]thiazole-2-ylthio)-
3-hydroxyhexanoate (32) (870 mg, 1.81 mmol) and NaHCO3
(1.84 g, 219 mmol) in acetone (30 mL) at 0 °C was added a mixture
of Oxone® (7.33 g, 11.8 mmol) in water (15 mL) cautiously and
portionwise. The reaction mixture was stirred at 0 °C for 1 d. The
mixture was diluted with cold water (100 mL), extracted with cold
Et2O (5ϫ70 mL) and dried (Na2SO4). Evaporation of the solvent
gave a mixture of the sulfones 37 and 38 as unstable colorless solids
(774 mg, 84%). Rf = 0.22 (petroleum ether/EtOAc = 5:1). 1H NMR
(500 MHz, CDCl3): δ = 0.82–0.86 (m, 6 H, 2ϫ CH3), 1.18–1.25
(m, 36 H, 18ϫ CH2), 1.49–1.70 (m, 12 H, 6ϫ CH2), 1.89–1.96 (m,
4 H, 2ϫ CH2), 2.27 (m, 4 H, 2ϫ CH2), 3.651 (s, 3 H, CH3), 3.65
(s, 3 H, CH3), 3.69–3.74 (m, 2 H, 2ϫ CH), 4.15–4.19 (m, 2 H, 2ϫ
CH), 7.57–7.65 (m, 4 H, arom. CH), 8.00–8.02 (m, 2 H, arom. CH),
8.19–8.20 (m, 2 H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3):
δ = 14.1 (CH3), 22.5, 22.6, 24.72, 24.76, 25.5, 25.60, 25.65, 26.9,
27.0, 28.7, 28.8, 28.9, 29.05, 29.09, 29.1, 29.24, 29.29, 29.4, 31.71,
31.78, 33.93, 33.97, 34.2 (CH2), 51.5 (CH3), 69.2, 69.3, 69.8, 69.9
(CH), 122.2, 125.3, 127.6, 127.9 (arom. C), 136.5, 152.3, 167.3
121.3, 124.4, 126.1 (arom. C), 135.4, 152.6, 167.5 (arom. Cipso
ppm. LRMS: m/z 360 [M
Na]+. HRMS: calcd. for
C18H27NS2NaO 360.1426 [M + Na]+; found 360.1422.
(E)-3-(Benzo[d]thiazol-2-ylthio)-8-benzyloxy-2,6-dimethyloct-6-en-2-
ol (35): To a mixture of 9 (700 mg, 3.05 mmol) was added Et3N (arom. Cipso), 174.33, 174.38 (CO) ppm. LRMS: m/z = 534 [M +
)
=
+
1996
www.eurjoc.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 1989–1998

New Methodology for the Conversion of Epoxides to Alkenes
Na]+. HRMS: calcd. for C26H41NS2NaO5 534.2318 [M + Na]+;
found 534.2305.
3.79–3.81 (m, 2 H, 2ϫ CH), 4.46 (dd, J = 11.7, 7.4 Hz, 2 H, 2-Ha,
2Ј-Ha), 4.57 (dd, J = 11.7, 4.7 Hz, 2 H, 2-Hb, 2Ј-Hb), 7.29–7.34 (m,
10 H, arom. CH), 7.58–7.63 (m, 4 H, arom. CH), 7.98–8.01 (m, 2
H, arom. CH), 8.19 (d, J = 8.1 Hz, 2 H, arom. CH) ppm. 13C
NMR (125 MHz, CDCl3): δ = 16.1, 16.6 (CH3), 21.8, 22.1 (CH2),
26.7, 27.5, 28.3, 29.2 (CH3), 37.1, 37.9 (CH3), 60.1, 61.4 (CH),
68.41, 68.49 (CH2), 72.2 (CH) 72.8, 72.9, 73.32, 73.37 (CH2),
122.36, 122.37, 125.3, 127.7, 127.95, 127.97, 128.14, 128.17, 128.40,
128.45 (arom. C), 136.51, 136.58, 137.2, 137.5, 152.2, 152.3, 167.1,
167.2 (arom. Cipso) ppm. LRMS: m/z = 498 [M + Na]+. HRMS:
calcd. for C24H29NS2NaO5 498.1379 [M + Na]+; found 498.1364.
3-(Benzo[d]thiazole-2-ylsulfonyl)-1,4-bis(benzyloxy)butan-2-ol (39):
To a solution of 3-(benzo[d]thiazole-2-ylthio)-1,4-bis(benzyloxy)
butan-2-ol (33, 111 mg, 0.25 mmol) and NaHCO3 (159 mg,
1.89 mmol) in acetone (6 mL) at 0 °C was added a mixture of
Oxone® (471 mg, 0.76 mmol) in water (3 mL) cautiously and por-
tionwise. The reaction mixture was stirred at 0 °C for 10 h. The
mixture was diluted with cold water (50 mL), extracted with cold
Et2O (5ϫ 50 mL) and dried (Na2SO4). Removal of the solvent gave
the sulfone 38 as an unstable yellow oil (101 mg, 84%). Rf = 0.26
1
5-Bromo-5-(bromomethyl)nonane (42): (i) To a solution of 2-
(benzo[d]thiazole-2-ylsulfonyl)methyl)nonan-5-ol (36, 120 mg,
0.34 mmol) in dry CH2Cl2 (15 mL) was added DBU (104 mg,
0.68 mmol). The reaction mixture was stirred at room temperature
for 5 h under argon. The reaction mixture was treated with catalytic
amount of pyridine (0.02 mL) and bromine (53.5 mg, 0.33 mmol),
and then stirred at room temperature overnight. Carbon tetrachlo-
ride (10 mL) was added to the reaction mixture. Removal of the
(petroleum ether/EtOAc = 7:3). H NMR (500 MHz, CDCl3): δ =
3.35 (br. s, 1 H, OH), 3.61 (dd, J = 10.2, 4.8 Hz, 1 H, 1-Ha), 3.72
(dd, J = 10.2, 3.3 Hz, 1 H, 1-Hb), 3.80 (dd, J = 11.8, 5.8 Hz, 1 H,
1Ј-Ha), 4.13–4.16 (m, 2 H, 1Ј-Hb, CH), 4.23 (d, J = 11.7 Hz, 1 H,
2-Ha), 4.37 (d, J = 11.9 Hz, 1 H, 2-Hb), 4.40 (d, J = 12.0 Hz, 1 H,
2Ј-Ha), 4.55 (d, J = 11.8 Hz, 1 H, 2Ј-Hb,), 4.65–4.67 (m, 1 H, CH),
6.99 (d, J = 6.9 Hz, 2 H, arom. CH), 7.12–7.19 (m, 3 H, arom.
CH), 7.26–7.33 (m, 5 H, arom. CH), 7.54 (t, J = 7.3 Hz, 1 H, arom.
CH), 7.60 (t, J = 7.4 Hz, 1 H, arom. CH), 7.91 (d, J = 8.0 Hz, 1
H, arom. CH), 8.16 (d, J = 8.1 Hz, 1 H, arom. CH) ppm. 13C
NMR (125 MHz, CDCl3): δ = 64.9 (CH2), 67.6, 67.7 (CH), 70.5,
73.2, 73.4 (CH2), 122.2, 125.2, 127.3, 127.6, 127.7, 127.93, 127.98,
128.13, 128.4 (arom. C), 136.5, 136.7, 137.2, 152.2, 167.3 (arom.
solvent gave
a crude residue, which was purified by flash
chromatography (petroleum ether) to give the dibromide 42 as a
1
colorless oil (69 mg, 68%). Rf = 0.73 (petroleum ether). H NMR
(500 MHz, CDCl3): δ = 0.94 (t, J = 7.2 Hz, 6 H, 2ϫ CH3), 1.32–
1.43 (m, 4 H, 2ϫ CH2), 1.44–1.54 (m, 4 H, 2ϫ CH2), 1.82–1.95
(m, 4 H, 2ϫ CH2), 3.82 (s, 2 H, CH2) ppm. 13C NMR (125 MHz,
CDCl3): δ = 13.9 (CH3), 22.5, 27.0, 39.4, 40.9 (CH2), 73.9 (C) ppm.
HRMS: calcd. for C10H20Br 219.0143, 221.0143 [M]; found
219.0745, 221.0723. C10H20Br2: calcd. C 40.03, H 6.72; found C
40.37, H 6.65.
C
ipso) ppm. LRMS: m/z = 506 [M + Na]+. HRMS: calcd. for
C25H25NS2NaO5 506.1066 [M + Na]+; found 506.1058.
5-(1-(Benzo[d]thiazol-2-ylsulfonyl)ethyl)nonan-5-ol (40): To a solu-
tion of 5-(1-(benzo[d]thiazol-2-ylthio)ethyl)nonan-5-ol 34 (190 mg,
0.56 mmol) and NaHCO3 (450 mg, 5.36 mmol) in acetone (14 mL)
at 0 °C was added a mixture of Oxone® (1.75 g, 2.82 mmol) in
water (7 mL) cautiously and portionwise. The reaction mixture was
stirred at 0 °C for 2 d. The mixture was diluted with ice-cold water
(30 mL), extracted with ice-cold CH2Cl2 (5ϫ 30 mL) and dried
(Na2SO4). Evaporation of the solvent gave the sulfone 40 as an
unstable colorless solid (200 mg, 96%). Rf = 0.54 (petroleum ether/
EtOAc = 4:1). 1H NMR (500 MHz, CDCl3): δ = 0.85 (t, J = 7.3 Hz,
3 H, CH3), 0.92 (t, J = 7.2 Hz, 3 H, CH3), 1.14–1.37 (m, 8 H, 4ϫ
CH2), 1.41 (d, J = 7.2 Hz, 3 H, CH3), 1.47–1.53 (m, 2 H, CH2),
1.74–1.81 (m, 2 H, CH2), 4.00 (q, J = 7.2 Hz, 1 H, CH), 7.58–7.66
(m, 2 H, arom. CH), 8.00–8.02 (m, 1 H, arom. CH), 8.22–8.24 (m,
1 H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ = 11.7, 14.0,
14.1 (CH3), 23.0, 23.1, 24.8, 25.0, 36.7 (CH2), 36.9 (CH), 53.4 (C),
66.3 (CH), 122.2, 125.5, 127.7, 128.1 (arom. C), 136.7, 152.5, 166.1
(arom. Cipso) ppm. LRMS: m/z = 392 [M + Na]+. HRMS: calcd.
for C18H27NS2NaO3 392.1325 [M + Na]+; found 392.1313.
(ii) To a solution of 17 (196 mg, 1.39 mmol) in hexane (2 mL) under
argon was added pyridine (0.08 mL) and excess bromine slowly.
The reaction was stirred at room temperature for 4 h. Removal of
the solvent gave a crude residue which was purified by flash
chromatography (petroleum ether) to give the dibromide 42
(232 mg, 56%), identical to that described above.
3-(Benzyloxymethyl)-2-methyl-2-(4-methylpent-3-enyl)oxirane (43):
To a solution of (E)-3-(benzo[d]thiazol-2-ylsulfonyl)-5-(3-benzyl-
oxymethyl-2-methyloxiran-2-yl)-2-methylpentan-2-ol (41, 180 mg,
0.38 mmol) in dry CH2Cl2 (10 mL) was added DBU (121 mg,
0.78 mmol). The reaction mixture was stirred at room temperature
for 3 h under argon. Evaporation of the solvent gave a crude mix-
ture, which was purified by silica flash column chromatography
(petroleum ether/EtOAc = 4:1) to give the epoxy alkene 43[36]
(71.8 mg, 73%) as a colorless oil. Rf = 0.57 (petroleum ether/EtOAc
1
= 4:1). H NMR (500 MHz, CDCl3): δ = 1.25 (s, 3 H, CH3), 1.45–
1.51 (m, 1 H, 2-Ha), 1.60 (s, 3 H, CH3), 1.62–1.65 (m, 1 H, 2-Hb),
1.67 (s, 3 H, CH3), 2.05–2.10 (m, 2 H, CH2), 3.01 (dd, J = 6.0,
4.5 Hz, 1 H, CH), 3.55 (dd, J = 11.2, 6.1 Hz, 1 H, 3-Ha), 3.68 (dd,
J = 11.2, 4.5 Hz, 1 H, 3-Hb), 4.53 (d, J = 11.9 Hz, 1 H, 4-Ha), 4.63
(d, J = 11.8 Hz, 1 H, 4-Hb), 5.07–5.10 (m, 1 H, CH), 7.28–7.35 (m,
5 H, arom. CH) ppm. 13C NMR (125 MHz, CDCl3): δ = 16.7, 23.6,
25.6, 38.3 (CH3, CH2), 61.2, 68.8, 73.1 (C, CH, CH2), 123.4, 127.7,
128.4, 132.0, 137.9 (C, CH, arom. C) ppm.
(E)-3-(Benzo[d]thiazol-2-ylsulfonyl)-5-(3-(benzyloxymethyl)-2-meth-
yloxiran-2yl)-2-methylpentan-2-ol (41): To a suspension of (E)-3-
(benzo[d]thiazol-2-ylthio)-8-(benzyloxy)-2,6-dimethyloct-6-en-2-ol
(35, 1.4 g, 3.28 mmol) and NaHCO3 (3.47 g, 41.3 mmol) in acetone
(30 mL) at 0 °C was added
a
solution of Oxone® (13.5 g,
21.8 mmol) in water (15 mL) cautiously and portionwise. The reac-
tion mixture was stirred at 0 °C for 3 d. The mixture was diluted
with ice-cold water (50 mL), extracted with ice-cold CH2Cl2 (5ϫ
50 mL) and dried (Na2SO4). Evaporation of the solvent gave the
sulfone 41 as an unstable colorless solid (1.51 g, 97%). Rf = 0.21
General Procedure for Desulfonation of 36–41: (i) To a solution of
sulfone (1 equiv.) in DCM or MeOH, was added DBU (2 equiv.)
slowly. The mixture was stirred under argon The solvent was re-
moved under reduced pressure and the crude residue was purified
by chromatography to afford the alkenes 17–20 and 43.
1
(petroleum ether/EtOAc = 4:1). H NMR (500 MHz, CDCl3): δ =
1.15 (s, 3 H, CH3), 1.16 (s, 3 H, CH3), 1.37 (s, 3 H, CH3), 1.39 (s,
3 H, CH3), 1.47 (s, 3 H, CH3), 1.53 (s, 3 H, CH3), 1.66–1.75 (m, 2
H, CH2), 1.79–1.85 (m, 2 H, CH2), 1.92–2.02 (m, 2 H, CH2), 2.18–
2.21 (m, 2 H, CH2), 2.85 (dd, J = 6.1, 4.5 Hz, 1 H, CH), 2.98 (t, J
(ii) A solution of the sulfone 36–41 in toluene was heated at reflux
= 5.6 Hz, 1 H, CHЈ), 3.45 (dd, J = 11.1, 6.1 Hz, 1 H, 1-Ha), 3.55 until TLC analysis indicated complete consumption of starting ma-
(t, J = 5.5 Hz, 2 H, 1Ј-H), 3.61 (dd, J = 11.1, 4.4 Hz, 1 H, 1-Hb), terial. The toluene was removed under reduced pressure and the
Eur. J. Org. Chem. 2010, 1989–1998
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
1997

F.-L. Wu, B. P. Ross, R. P. McGeary
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alkenes 17–20 and 43.
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Published Online: February 18, 2010
1998
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