A facile tetrahydrothiophene-catalyzed ylide route to vinyloxiranes

Article abstract of DOI:10.1039/b304443b

Access to vinyloxiranes using aldehydes and allylic bromides in the presence of 1-5 mol% tetrahydrothiophene is reported. Both aliphatic and aromatic aldehydes work well in this reaction and the catalyst loading could be reduced as low as 0.5 mol%.

Full text of DOI:10.1039/b304443b

A facile tetrahydrothiophene-catalyzed ylide route to vinyloxiranes†
Kai Li, Xian-Ming Deng and Yong Tang*
Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, 354 Fenglin Lu,
Shanghai 200032, China. E-mail: tangy@mail.sioc.ac.cn
Received (in Cambridge, UK) 24th April 2003, Accepted 30th June 2003
First published as an Advance Article on the web 10th July 2003
Access to vinyloxiranes using aldehydes and allylic bromides
in the presence of 1–5 mol% tetrahydrothiophene is re-
ported. Both aliphatic and aromatic aldehydes work well in
this reaction and the catalyst loading could be reduced as
low as 0.5 mol%.
both aldehyde and allylic bromide are used in a one-pot reaction
because the high concentration of allylic bromide is beneficial
to the formation of sulfur salt and the high concentration of
aldehyde could probably lead to the reaction of aldehydes with
the sulfur ylide before the ylide rearranged. As alcoholic
solvents were found to activate the aldehyde probably due to the
1
6
Sulfur ylides, particularly sulfur benzylides, have been devel-
formation of hydrogen bonds between solvent and aldehyde,
1
oped as good reagents for the preparation of oxirane,
cyclopropane and aziridine derivatives since Johnson et al.
we chose t-BuOH as the solvent and used 5 mol% tetra-
hydrothiophene as the catalyst to start our study. As expected,
this catalytic reaction proceeded very well. As shown in Table
1, the reaction of 4-chlorobenzaldehyde with allylbromide 2a at
reflux in the presence of 5 mol% tetrahydrothiophene gave the
2
3
4
found the reaction of sulfur ylide with aldehydes in 1961.
5
Although vinyloxiranes are versatile building blocks and
6
precursors of functionalized four-carbon sequences, the reac-
tions of allylic sulfur ylide with aldehydes, imines and electron-
deficient alkenes were less explored than other ylide reactions,
and it is still a challenging problem due to its easy [2,3]7
sigmatropic rearrangement. In order to obviate this rearrange-
desired product in quantitative yield when either Cs
2 3
CO or
K
2
CO was used as the base. This reaction could also be carried
3
out without solvent, but the yield was lower than that when t-
BuOH was used as the solvent (entry 4 in Table 1). Gratifyingly,
the yield was still 83% even when the loading of tetra-
hydrothiophene was reduced to 0.5 mol% (entry 6).
8
ment, typically, diphenyl sulfur ylide was used. Arsenic or
9
tellurium ylides have been also employed to avoid the [2,3]
sigmatropic rearrangement. In this way, the desired catalytic
Further studies showed that both aromatic and aliphatic
aldehydes worked very well even on the gram-scale. As
described in Table 2, both electron-rich and electron-deficient
aromatic aldeydes gave the desired epoxides in excellent yields
(entries 1–4). Compared with aromatic aldehydes, aliphatic
aldehydes such as cyclohexanecarboxaldehyde and decyl
aldehyde always are less active in catalytic ylide reactions. But
under our conditions, they worked well (entries 5, 10 and 11).
Although the stereoselectivity was not good, the isomers could
be separated easily as a single cis- and/or trans-isomer by flash
chromatography. Noticeably, b-trimethylsilylallyl bromide also
participated in this reaction to give the corresponding epoxides
in excellent yields using only 1 or 5 mol% of catalyst (entries
6–11).
We also tried catalytic asymmetric ylide epoxidation by the
use of chiral sulfides 4, 5 and 6 as the catalyst. Only moderate
yields were achieved in the presence of sulfide 4 or 6. The
enantioselectivities were low to moderate (entries 1 and 3 in
Table 3). Sulfide 5 could not catalyze this reaction probably
because the formation of salt is very difficult.
version10 was realized by using 20 mol% diisobutyl telluride.
11
Recently, Dai and Hou reported a one-pot strategy for the
synthesis of vinylaziridines and vinyl epoxides via sulfur ylides.
In some cases, they found that the stereoselectivities of ylide
expoxidation1 and/or aziridination
1a
3a,11b,c,12
could be tuned by
changing both the reaction conditions and the ligands of sulfur
ylides. In our study of ylide chemistry,13 we documented an
enantioselective preparation of vinylcyclopropanes using stoi-
chiometric chiral ylides.14 Very recently, Metzner et al.
described the first enantioselective synthesis of vinyl oxiranes
from allylic chiral sulfur ylides.15 To the best of our knowledge,
no catalytic ylide epoxidation via allylic sulfur ylide has been
reported, except that Aggarwal et al. reported that benzaldehyde
reacted with (3,3-diphenyl)alkenyl sulfonyl hydrazone to afford
diphenyl vinyl epoxide in the presence of 20 mol% tetra-
hydrothiophene.1b Here we report an efficient catalytic route to
vinyloxiranes via allylic sulfur ylide.‡
By careful analysis of the reaction of allylic sulfur ylide in the
presences of aldehyde (Scheme 1), we think that it is possible to
realize catalytic ylide epoxidation when high concentrations of
In conclusion, we have developed an efficient catalytic ylide
route to vinyloxiranes via allylic sulfur ylides. The cheap and
Table 1 Effects of reaction conditions on catalytic ylide epoxidation
Loading
Entry
Solvent
(mol%)a
Base
Cs CO
Yieldb
1
2
3
4
5
6
a
t-BuOH
t-BuOH
t-BuOH
—
t-BuOH
t-BuOH
5
5
1
1
1
0.5
2
3
100
100
100
58
51
83
K CO
2
K CO
2
K CO
2
K CO
2
K CO
2
3
3
3
3
3
Scheme 1
c
†
Electronic supplementary information (ESI) available: preparation of
vinyloxiranes and chiral catalysts. See http://www.rsc.org/suppdata/cc/b3/
b304443b/
Tetrahydrothiophene loading. b Determined by GC. c Trace amount of
water was added.
2
074
CHEM. COMMUN., 2003, 2074–2075
This journal is © The Royal Society of Chemistry 2003

Table 2 Reactions of aldehydes with allylic bromides catalyzed by
tetrahydrothiophene
obenzaldehyde (907 mg, 6.5 mmol), dry K
mmol ) and t-BuOH (2 mL, distilled over sodium) under N
2
CO
3
(powdered, 1.07 g, 7.8
atmosphere.
a
2
The resulting mixture was refluxed for 12 h, and then filtered rapidly
through a short silica gel column (ethyl acetate eluent). The filtrate was
concentrated and the residue was purified by chromatography (hexane/ethyl
acetate, 200/1, v/v) on silica gel to afford the desired product, 1.09 g
(94%).
Entry Loadingb
R
R1
cis/transc Yield (%)d
1
(a) V. K. Aggarwal, H. Abdel-Rahman, L. Fan, R. H. Jones and M. H.
1
2
3
4
5
6
7
8
9
0
1
1
1
1
5
5
1
1
1
1
5
5
4-ClC
6
H
4
H
H
H
H
36/64
33/67
38/62
30/70
55/45
25/75
24/76
30/70
27/73
42/58
50/50
94
85
96
85
75
83
89
85
85
88
78
Standen, Chem. Eur. J., 1996, 2, 1024; (b) V. K. Aggarwal, E. Alonso,
G. Hynd, K. M. Lydon, M. J. Palmer, M. Porcelloni and J. R. Studley,
Angew. Chem., Int. Ed., 2001, 40, 1430; (c) J. Zanardi, C. Leriverend, D.
Aubert, K. Julienne and P. Metzner, J. Org. Chem., 2001, 66, 5620; (d)
K. Julienne, P. Metzner, V. Henryon and A. Greiner, J. Org. Chem.,
C
H
6 5
4-NO
4-CH
n-C
4-ClC
2
C
6
H
4
3
OC
19
6
H
4
9
H
H
H
6 4
TMS
TMS
TMS
TMS
TMS
TMS
1
998, 63, 4532; (e) V. K. Aggarwal, J. N. Harvey and J. Richardson, J.
6 5
C H
Am. Chem. Soc., 2002, 124, 5747; (f) V. K. Aggarwal, G. Hynd, W.
Picoul and J.-L. Vasse, J. Am. Chem. Soc., 2002, 124, 9964.
(a) V. K. Aggarwal, J. D. Vicente and R. V. Bonnert, Org. Lett., 2001,
4-NO
2 6 4
C H
2-ClC
H
6 4
2
3
1
1
a
9 19
n-C H
3
, 2785; (b) V. K. Aggarwal, E. Alonso, G. Fang, M. Ferrara, G. Hynd
cyclo-C
6
H
11
and M. Porcelloni, Angew. Chem., Int. Ed., 2001, 40, 1433.
All reactions were carried out in one-pot at reflux using tetra-
(a) A.-H. Li, Y.-G. Zhou, L.-X. Dai, X.-L. Hou, L.-J. Xia and L. Lin, J.
Org. Chem., 1998, 63, 4338; (b) V. K. Aggarwal, M. Ferrara, C. J.
O’Brien, A. Thompson, R. H. Jones and R. Fieldhouse, J. Chem. Soc.,
Perkin Trans. 1, 2001, 1635; (c) V. K. Aggarwal, J. H. Charmant, C.
Ciampi, J. M. Hornby, C. J. O’Brien, G. Hynd and R. Parsons, J. Chem.
Soc., Perkin Trans. 1, 2001, 3159.
hydrothiophene (0.06 mmol), b-trimethylsilylallyl bromide (9.75 mmol) [or
allylbromide (19.4 mmol)], aldehyde (6.5 mmol), K CO (7.8 mmol), t-
atmosphere. mol%. c Determined by GC.
2
3
b
BuOH (2 mL) under dry N
2
d
Isolated yield.
4
5
A. W. Johnson and R. B. LaCount, J. Am. Chem. Soc., 1961, 83, 417.
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B. M. Trost and I. Fleming, Pergamon, Oxford, 1991, vol. 5, p. 899; (b)
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Table 3 Asymmetric ylide epoxidations of 1aa
3
9, 4079; (c) E. Schaumann and F. Tries, Synthesis, 2002, 191; (d) C.
Hertweck and W. Boland, J. Org. Chem., 2000, 65, 2458; (e) C.
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6
7
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8
9
c
Loading
(mol%)
ee (%) for
cis/transb trans-3f
2
Entry
Cat.
Yield (%)
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6
1
2
3
a
4
5
6
20
20
5
40 : 60
—
34 : 66
37
—
25
40
0
51
598.
0 Z.-L. Zhou, L.-L. Shi and Y.-Z. Huang, Tetrahedron Lett., 1990, 31,
657.
1
7
All reactions were carried out in one-pot at reflux using catalyst, b-
CO (0.6
atmosphere. Determined by GC.
11 (a) Y.-G. Zhou, A.-H. Li, X.-L. Hou and L.-X. Dai, Chem. Commun.,
1996, 1353; (b) A.-H. Li, L.-X. Dai and X.-L. Hou, Chem. Commun.,
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Chem., 1996, 61, 4641.
trimethylsilylallyl bromide (0.6 mmol), aldehyde (0.5 mmol), K
2
3
b
mmol), t-BuOH (0.5 mL) under dry N
2
c
Determined by HPLC.
1
2 (a) X.-L. Hou, X.-F. Yang, L.-X. Dai and X.-F. Chen, Chem. Commun.,
998, 747; (b) X.-F. Yang, M.-J. Zhang, X.-L. Hou and L.-X. Dai, J.
Org. Chem., 2002, 67, 8097.
1
readily available catalyst, the simple procedure, the mild
conditions and the high catalytic efficiency together with the
easy separation of cis/trans-isomers, make this method poten-
tially useful in organic synthesis.
This research was supported by the National Natural Sciences
Foundation of China and ‘The Talent Scientists Program’ from
Chinese Academy of Sciences.
13 (a) S. Ye, L. Yuan, Z.-Z. Huang, Y. Tang and L.-X. Dai, J. Org. Chem.,
2000, 65, 6257; (b) S. Ye, Y. Tang and L.-X. Dai, J. Org. Chem., 2001,
66, 5717; (c) Z.-Z. Huang, S. Ye, W. Xia and Y. Tang, Chem. Commun.,
2
5
001, 1384; (d) Z.-Z. Huang and Y. Tang, J. Org. Chem., 2002, 67,
320; (e) Z.-Z. Huang, S. Ye, W. Xia, Y.-H. Yu and Y. Tang, J. Org.
Chem., 2002, 67, 3096.
1
4 S. Ye, Z.-Z. Huang, C.-A. Xia, Y. Tang and L.-X. Dai, J. Am. Chem.
Soc., 2002, 124, 2432.
1
5 J. Zanardi, D. Lamazure, S. Miniére, V. Reboul and P. Metzner, J. Org.
Chem., 2002, 67, 9083.
Notes and references
‡
General procedure: To a Schlenk tube were added tetrahydrothiophene
16 (a) Y. Huang and V. H. Rawal, J. Am. Chem. Soc., 2002, 124, 9662; (b)
Y. Yuan, X. Li and K. Ding, Org. Lett., 2002, 4, 3309.
(5.7 mg, 0.06 mmol), allylbromide (1.68 mL, 19.4 mmol), 4-chlor-
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