Unexpected cis-selectivity in (Sylvestre) Julia Olefinations with Bu 3Sn-containing allyl benzothiazolyl sulfones: Stereoselective synthesis of 1,3-butadienyl- and 1,3,5-hexatrienylstannanes

Article abstract of DOI:10.1055/s-2004-837213

Bu₃Sn-substituted benzothiazolyl sulfones 1c, 1d, and 1f were subjected to Julia olefmation reactions with a variety of aldehydes. cis-Selectivities up to 97:3 were obtained by using KHMDS as base in THF.

Full text of DOI:10.1055/s-2004-837213

LETTER
289
Unexpected cis-Selectivity in (Sylvestre) Julia Olefinations with Bu Sn-
3
Containing Allyl Benzothiazolyl Sulfones: Stereoselective Synthesis of
1
,3-Butadienyl- and 1,3,5-Hexatrienylstannanes
S
A
tereoselective
S
y
c
nthesis of
1
h
,3-Butadieny
i
l- and
m
1,3, 5-Hexatrienylstannane
S
s
org, Reinhard Brückner*
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany
Fax +49(761)2036100; E-mail: reinhard.brueckner@organik.chemie.uni-freiburg.de
Received 28 October 2004
Abstract: Bu Sn-substituted benzothiazolyl sulfones 1c, 1d, and 1f
3
were subjected to Julia olefination reactions with a variety of alde-
hydes. cis-Selectivities up to 97:3 were obtained by using KHMDS
as base in THF.
S
N
O
S O
Key words: alkenylstannanes, dienes, Julia–Lythgoe olefination,
O
SnBu3
stereoselectivity, trienes
+
Bu3Sn
1
f
2
a or b
a-Lithiated alkyl aryl sulfones add readily to aldehydes.
The resulting b-(arenesulfonyl) alkoxides can be acylated
re-
ref. 11: visited:
5
6
–
often in situ – and subsequently reduced in an overall
sequence, which is known as the (Marc) Julia–Lythgoe
olefination. The main virtues of this strategy are consid-
1
cis-3
not
:
94
:
Bu Sn
3
SnBu3
erable functional group compatibility and reliable trans-
+
2
selectivity. Sylvestre Julia shortened this olefin synthesis
5
6
SnBu3 only
6
to a single step by starting from a-lithioalkyl (or a-lithio-
Bu3Sn
3a–3c
allyl or a-lithiobenzyl) benzothiazolyl sulfones.
Un-
trans-3
der these conditions, the sulfonylalkoxide intermediates
undergo an S→O shift of the benzothiazol group. De-
pending on which fragmentation mechanism is realized,
the C=C bond is established cis selectively (1-step frag-
mentation) or trans selectively (2-step fragmentation).3
As a rule of thumb, a-lithioalkyl benzothiazolyl sulfones
S
N
b,c
O
S
O
+
O
SnBu3
3
c,4
Bu3Sn
deliver cis-olefins
and a-lithioallyl or a-lithiobenzyl
3c–3f
benzothiazolyl sulfones trans-olefins.
1c
4
c
Dienyl- or more highly conjugated stannanes have not
been prepared by (Marc) Julia–Lythgoe, (Sylvestre) Julia
3
4
3
,5–8
or related lithiosulfone-based olefinations
systemati-
cally, yet in a few isolated instances: (1) our own group
exploited Kende’s variant of the (Marc) Julia–Lythgoe
Bu3Sn
SnBu3
96
:
9
cis-5
olefination for making 1-(tributylstannyl)-1,3-hexa-
+
3
4
1
0
diene. (2) De Lera et al. reported a (Sylvestre) Julia
SnBu3
4
Bu3Sn
synthesis of the 1,w-bis(tributylstannyl)-1,3,5,7,9-deca-
1
1
pentaene (3, Scheme 1, top). (3) We described an analo-
gous synthesis of the 1,w-bis(tributylstannyl)-1,3,5-
trans-5
1
2
hexatriene (5, Scheme 1, bottom). Therein the newly
formed C=C bond resulted with 96:4 cis-selectivity (!).
Since this contrasted with the trans-selectivity usually ob-
served in lithioallyl benzothiazolyl sulfone olefinations
in the following
BT (for benzothiazolyl)
S
N
(
vide supra) we undertook the present study. It demon-
strates that (Sylvestre) Julia olefinations constitute a Scheme 1 Previous sulfone-based syntheses of conjugated alkenyl-
1
1
stannanes. Reagents and conditions: a) Ref. : 1f (1.2 equiv),
NaHMDS (1.2 equiv), THF, –78 °C, 45 min; 2, THF, –78 °C to
2
5 °C, 12 h; 83%, ‘high stereoselectivity’; b) 1f (1.12 equiv), 2 (1.0
SYNLETT 2005, No. 2, pp 0289–0293
Advanced online publication: 17.12.2004
DOI: 10.1055/s-2004-837213; Art ID: G39004ST
0
1.
0
2.
2
0
0
5
equiv), KHMDS (1.12 equiv), THF, –78 °C to r.t., 2 h; 63% of the
9
h; 66% of the 96:4 mixture.
12
4:6 mixture: c) ref. : KHMDS (1.2 equiv), THF, –78 °C to r.t., 12
©
Georg Thieme Verlag Stuttgart · New York

2
90
A. Sorg, R. Brückner
LETTER
general route to conjugated alkenylstannanes and estab- Table 2 Variation of the Benzothiazolyl Sulfone in Olefinations of
the Stannylated Aldehyde 4a
lishes that the new C=C bond is always cis-configured.
"
base", THF, –78 °C
Indeed, the C=C bond emerging from a repetition of the
1
1
13
de Lera synthesis of polyene 3 was cis-configured, too.
O
SnBu3
4
2
3
1
1
SnBu3
This was proved by a H-coupled short-range C,H corre-
lation spectrum. It revealed that the crucial H,H coupling
J5,6 of 3major isomer is 11.2 Hz (Scheme 1). In contrast, J5,6 in
an independently prepared sample of isomer trans-3 was
R
2
SO BT
R
4
,
1
a–c, e, f
8, 9, 5, 10, 11
–
78 °C
r.t.
Diene Yield ,4cis:
3
Entry R
Sulfone Base
1
4
1
1
4.4 Hz, again according to a H-coupled short-range
3,4
(
%)
trans
C,H correlation spectrum.
1
2
1a
1b
LDA
KHMDS
8
9
78
78
47:53
39:61
Table 1 Benzothiazolyl Sulfone Synthesesa
a
b
3
4
LDA
KHMDS
59
60
91:9
90:10
R
OH
a–g
R
SBT
7a–g
R
SO2BT
1a–g
6
5
1c
1e
KHMDS
5
66
96:4
Bu3Sn
Alcohol/sulfide/ R
sulfone
Yield of
sulfide (%) sulfone (%)
Yield of
6
7
LDA
KHMDS
10
41
43
71:29
39:61
a
b
c
99
93
96
68
8
9
1g
LDA
KHMDS
11
33
38
95:5
95:5
77
83b
a
Bu3Sn
The product stannanes were isolated as isomeric mixtures.
d
e
f
98
96
95
98
90b
74
48
66
in THF solution at –78 °C testing the following sets of
conditions: (1) LDA or (2) KHMDS, followed by the ad-
dition of the aldehyde 4–18 minutes later; (3) LDA, (4)
LiHMDS or (5) KHMDS in the presence of the aldehyde
Bu3Sn
(
‘Barbier conditions’). The temperature was slowly (2–6
Bu3Sn
h) raised to room temperature. Extractive workup and pu-
17
g
rification by flash chromatography on silica gel provid-
ed dienylstannane 8, trienylstannanes 5, 9, and 10, and
dienynylstannane 11 in yields of 33–78%. Cis-selectivi-
ties reached 95:5 to 96:4 (entries 5, 8, 9) starting from our
a
Reagents and conditions: a) Benzo-1,3-thiazole-2-thiol (1.06 equiv),
PPh (1.10 equiv), diethyl azodicarboxylate (1.09 equiv), THF, 0 °C,
18
3
tin-containing allyl sulfone 1e or – as could be expected
1
–1.5 h; b) H O (8–11 equiv), (NH ) Mo O (0.20 equiv), EtOH,
2 2 4 6 7 24
–
from the propargyl sulfone 1g. Runner-up was the tin-
0
°C, 30 min to 6 h.
b
free allyl sulfone 1b (→ 91:9 cis:trans) while propyl
sulfone 1a and prenyl sulfone 1e olefinated virtually with-
out stereocontrol.
Sulfone was isolated after aqueous work-up, drying, and azeotropic
removal of water.
Table 3 summarizes (Sylvestre) Julia olefinations of a va-
riety of aldehydes using the metalated g-(tributylstan-
nyl)allyl benzothiazol sulfone 1c. Testing three base/
solvent combinations – namely LDA/THF, KHMDS/tol-
uene, and KHMDS/THF – the latter led to 93:7 to 97:3
cis-selectivities vs a,b-unsaturated aldehydes (entries 6, 7,
The preparation of the required benzothiazolyl sulfones
8
relied on established methodology (Table 1): Alcohols
6
a–g were converted into benzothiazolyl sulfides 7a–g15
by a Mitsunobu substitution, and subsequent oxidation
with peroxomolybdate(VI) furnished the corresponding
1
6
sulfones 1a–g. The only complication was destannylation,
1
1, and 14) as did KHMDS/toluene vs propionaldehyde
which competed with the oxidation of the Bu Sn-contain-
3
(
→ 92:8 cis:trans; entry 2). Benzaldehyde was the only
ing sulfides 7c,d,f. Accordingly, stannane 1f was separat-
aldehyde displaying less cis:trans selectivity (KHMDS/
THF → 84:16; entry 17).
ed – in the early fractions – from destannylated material
1
7
by flash chromatography on deactivated Al O . Yet,
2
3
stannylated sulfones 1c and 1d were too unstable for
analogous separations; they had to be used without purifi-
cation.
Table 4 shows (Sylvestre) Julia olefinations of a selection
of aldehydes with the metalated g-(tributylstannyl)crotyl
benzothiazol sulfone (1d). Deprotonation with KHMDS
compared to LDA gave slightly lower yields but distinctly
higher cis:trans selectivities (92:8 to 96:4) with aliphatic
(
Sylvestre) Julia olefinations where the sulfone substitu-
ent was varied are compiled in Table 2; in these reactions
-(tributylstannyl)acrolein (4) was maintained as a refer-
(
entry 2) and a,b-unsaturated aldehydes (entries 4, 6, 8).
3
Benzaldehyde, independent of the base, showed lower se-
lectivities (83:17 and 85:15, entries 9 and 10).
ence aldehyde. The alkyl (1a), allyl (1b,c,e) or propargyl
substituent (1g) of the respective sulfone was a-metalated
Synlett 2005, No. 2, 289–293 © Thieme Stuttgart · New York

LETTER
Stereoselective Synthesis of 1,3-Butadienyl- and 1,3,5-Hexatrienylstannanes
291
Table 3 Variation of the Aldehyde in Olefinations with the Stannyl- Last but not least, we found that de Lera’s pentadienyl
a
11
ated Benzothiazolyl Sulfone 1c
benzothiazolyl sulfone 1f, after metalation with KHMDS
base, solvent,
in THF, olefinates propionaldehyde with 86:14 cis selec-
tivity (Scheme 2).
1
3
–78 °C
2
4
R
Bu3Sn
SO2BT
Bu3Sn
12, 13, 5, 10, 14
O
R ,
r.t.
BT
1c
O
S O
a
5
6
3
,4
Bu3Sn
Bu3Sn
(
O
Entry
R
Base
LDA
Solvent Diene Yield cis:
3
,4
(
%)
trans
1f
20
86:14 cis:trans)
1
2
3
THF
8
60
61
50
60:40
92:8
91:9
KHMDS
KHMDS
Toluene
THF
Scheme 2 Olefinations with the stannylated benzothiazolyl sulfone
f. Reagents and conditions: a) 1f (0.96 equiv), KHMDS (1.33
1
equiv), THF, –78 °C, 8 min; propenal, –78 °C to r.t., 4 h; 58% of the
isomeric mixture.
4
5
6
LDA
KHMDS
KHMDS
THF
Toluene
THF
12
58
55
55
78:22
83:17
93:7
In summary, the cis:trans selectivities of the 1,3-dienyl-
and 1,3,5-hexatrienylstannane syntheses from aliphatic or
a,b-unsaturated aldehydes and the stannylated allyl ben-
zothiazolyl sulfone 1c (Table 3), the stannylated crotyl
benzothiazolyl sulfone 1d (Table 4) or the stannylated
pentadienyl benzothiazolyl sulfone 1f [Scheme 1 (top)
and Scheme 2] are uniformly ≥90:10. This is distinct from
the outcome of most (Sylvestre) Julia olefinations of the
same kind of aldehydes with analogous, albeit tin-free
benzothiazolyl sulfones:
7
SnBu3 KHMDS
THF
5
66
96:4
8
9
0
1
LDA
LiHMDS THF
KHMDS
KHMDS
THF
10
62
43
59
56
38:62
40:60
81:19
97:3
1
1
Toluene
THF
1
1
1
2
3
4
LDA
THF
Toluene
THF
13
14
62
60
50
40:60
79:21
94:6
Ph
KHMDS
KHMDS
1
1
1
5
6
7
Ph
LDA
KHMDS
KHMDS
THF
Toluene
THF
61
62
58
64:36
46:54
84:16
–
‘Simple’ a-lithioallyl benzothiazolyl sulfones establish
3c
trans-configured C=C bonds, as already briefly men-
tioned.
a
The product stannanes were isolated as isomeric mixtures.
–
–
‘More complex’ a-metaloallyl benzothiazolyl sulfones
used in natural product synthesis – provided the follow-
8
ing trans:cis olefin ratios (according to a recent review):
1
00:0 (employing four Li-b,g-dialkylallyl sulfones and
Table 4 Variation of the Aldehyde in Olefinations with the Stannyl-
ated Benzothiazolyl Sulfone 1d
a
one K-g-alkylallyl sulfone), 75:25 (employing a K-b,g-di-
alkylallyl sulfone), 40:60 (employing a metalated g-alkyl-
allyl sulfone), and 25:75 (employing a Na-pentadienyl
sulfone).
–
(Sylvestre) Julia olefination of 3-phenylpropionaldehyde
with a-lithiated geranyl benzothiazolyl sulfone does not
attain the cis selectivities highlighted in the present
study.3e
1
2
4
"
base", THF, –78 °C
3
5
R
Bu3Sn
SO2BT
Bu3Sn
O
R ,
r.t.
7
The 13:87 trans:cis ratio reported singularly for the
1d
15–19
4
4
,5
,5
Entry
R
Base
Diene Yield
cis
trans
1
2
LDA
KHMDS
15
16
17
18
19
68%
54%
63:37
96:4
Unfortunately, we cannot explain why Bu Sn-substituted
3
allyl benzothiazolyl sulfones undergo cis-selective
(Sylvestre) Julia olefinations. It is kind of a consolation
that others faced related ‘miracles’ of cis-selective Julia-
type olefinations, too (e. g. ref.1 ).
3
4
LDA
KHMDS
58%
58%
77:23
95:5
9,20
5
6
LDA
KHMDS
61%
56%
68:32
95:5
Sterically homogeneous 1-(trialkylstannyl)-1,3-dienes
related to the ones prepared in the present study – and
more extensively conjugated derivatives – have been
widely used in synthesis: for C,C-couplings with bro-
moalkenes, iodoalkenes, alkenyl triflates, iodoaro-
matics, and iodoalkynes as well as for Sn→Li,
Sn→Cu and Sn→I exchanges. Since C=C geometries
are almost always preserved in the mentioned reactions,
the 3 cis-configured 1-(trialkylstannyl)-1-3-dienes now
made accessible should extend their scope considerably.
7
8
Ph LDA
57%
52%
72:28
92:8
KHMDS
9
0
Ph
LDA
KHMDS
60%
55%
83:17
85:15
21
22
23
1
24
25
26
27
28
a
The product stannanes were isolated as isomeric mixtures.
,4
Synlett 2005, No. 2, 289–293 © Thieme Stuttgart · New York

2
92
A. Sorg, R. Brückner
LETTER
(12) (a) Brückner, R.; Siegel, K.; Sorg, A. In Strategies and
Acknowledgment
Tactics in Organic Synthesis, Vol. 5; Harmata, M., Ed.;
Elsevier: Amsterdam, 2004, 437–473. (b) Sorg, A.; Siegel,
K.; Brückner, R. Chem.–Eur. J. in press.
We are indebted to the Fonds der Chemischen Industrie for finan-
cial support and to Dr. Manfred Keller (Universität Freiburg) for
valuable spectroscopic support.
(
13) 3,8-Dimethyl-1,10-bis(tributylstannyl)-1,3,5,7,9-
decapentaene as a 94:6 mixture of cis-3 and trans-3: At
–
78 °C KHMDS (1.0 M in THF, 0.26 mL, 0.26 mmol, 1.12
equiv) was added to a solution of sulfone 1f (147.3 mg,
.259 mmol, 1.12 equiv) and aldehyde 2 (89.0 mg, 0.231
References
0
(
1) (a) First report: Julia, M.; Paris, J.-M. Tetrahedron Lett.
973, 4833. (b) Stereochemical investigations: Kocienski,
P. J.; Lythgoe, B.; Ruston, S. J. Chem. Soc., Perkin Trans. 1
978, 829. (c) Kocienski, P. J.; Lythgoe, B.; Waterhouse, I.
mmol, 1.00 equiv) in THF (1.5 mL), resulting in a purple
solution. This solution was warmed to r.t. over a period of 2
h. Pentane (4 mL) and brine (2 mL) were added. The
aqueous phase was extracted with pentane (2 × 2 mL) and
the combined organic extracts were washed with brine (2
mL). After drying with Na SO the solvent was removed in
vacuo. Flash chromatography [Al O (deactivated with 3%
H O), cyclohexane: Et N = 200:2] afforded the title
compound (142.2 mg, 63%; ref. : 83%) as a 94:6 mixture of
1
1
J. Chem. Soc., Perkin Trans. 1 1980, 1045.
(
2) (a) A cis-selective variant of the (Marc) Julia–Lythgoe
olefination was reported, too: Bremmer, J.; Julia, M.;
Launay, M.; Stacino, J. P. Tetrahedron Lett. 1982, 23, 3265.
2
4
2
3
(
b) Julia, M.; Lauron, H.; Stacino, J. P.; Verpeaux, J. N.;
2
3
1
1
Jeannin, Y.; Dromzee, Y. Tetrahedron 1986, 42, 2475. (c)
Select applications: Julia, M.; Stacino, J. P. Tetrahedron
cis-3 and trans-3 as a yellow oil. IR (film): n = 2955, 2925,
2870, 2855, 1560, 1465, 1455, 1375, 1070, 1005, 980, 960,
1
986, 42, 2469. (d) Cuvigny, T.; Dupenhoat, C. H.; Julia, M.
–
1 1
880, 875, 865, 760, 690, 665, 595 cm . H NMR (499.9
Tetrahedron 1987, 43, 859. (e) Holmes, A. B.; Pooley, G. R.
Tetrahedron 1992, 48, 7775.
MHz, C HD as internal standard in C D ): d = ca. 0.91–1.09
6
5
6
6
(
(
m, 6 × SnCH CH CH CH ), in part superimposed by 0.93
(
3) (a) First report: Baudin, J. B.; Hareau, G.; Julia, S. A.; Ruel,
O. Tetrahedron Lett. 1991, 32, 1175. (b) Stereochemical
studies: Baudin, J. B.; Hareau, G.; Julia, S. A.; Ruel, O. Bull.
Soc. Chim. Fr. 1993, 130, 336. (c) Baudin, J. B.; Hareau,
G.; Julia, S. A.; Lorne, R.; Ruel, O. Bull. Soc. Chim. Fr.
2
2
2
3
t, J = 7.3 Hz, 6 × SnCH CH CH CH ), 1.38 (tq, both
vic
2
2
2
3
Jvic = 7.6 Hz, 6 × SnCH CH CH CH ), 1.54–1.72 (m, 6 ×
SnCH CH CH CH ), 1.87 (d, J = 0.6 Hz, 3-CH , 8-CH ),
2
2
2
3
2
2
2
3
allyl
3
3
6.44 (m , 5-H, 6-H), 6.53 (d, J and J10,9 = 19.1 Hz, flanked
c 1,2
2
1
19
by Sn isotope satellites as 2 interlocked d, J
= 69.8 Hz,
1
993, 130, 856. (d) For an exception see: Bellingham, R.;
Jarowicki, K.; Kocienski, P.; Martin, V. Synthesis 1996,
85: A 71:29 cis:trans ratio was observed for the hexatrienes
Sn,H
2
1
17
J
= 66.3 Hz, 1-H, 10-H), 6.85 (br d, J4,5 and J7,6 = 8.2
Sn,H
Hz, 4-H, 7-H), 6.94 (d, J2,1 and J9,10 = 19.2 Hz, flanked by Sn
2
3
1
19
isotope satellites as 2 interlocked d, J
= 64.9 Hz,
resulting from an a-lithioallyl benzothiazolyl sulfone and an
a,b-unsaturated aldehyde. This ratio was increased to 82:18
employing the a-potassioallyl benzothiazolyl sulfone. (e)
Note added in proof: A 75:25 cis:trans ratio has been
published recently for the (Sylvestre) Julia olefination of a
multiply conjugated aldehyde with an a-sodiopentadienyl
benzothiazolyl sulfone: Furuichi, N.; Hara, H.; Osaki, T.;
Nakano, M.; Mori, H.; Katsumura, S. J. Org. Chem. 2004,
Sn,H
3
13
1
17
J
= 62.1 Hz, 2-H, 9-H). C NMR (125.7 MHz, C HD
Sn,H
6 5
as internal standard in C D ): d = 9.89 (flanked by Sn isotope
satellites as 2 d, J
SnCH CH CH CH ), 12.01 (3-CH , 8-CH ), 13.90
6
6
1
1
117
119
= 342.1 Hz, J
= 327.0 Hz,
Sn,C-1¢¢
Sn,C-1¢¢
2
2
2
3
3
3
(
SnCH CH CH CH ), 27.69 (flanked by Sn isotope
2
2
2
3
3
3
117
1
19
satellites as 1 d, J
SnCH CH CH CH ), 29.58 (flanked by Sn isotope satellites
as 1 d, J
= J
= 54.2 Hz,
Sn,C-3¢¢
Sn,C-3¢¢
2
2
2
3
2
2
117
1
19
= J
= 20.6 Hz,
69, 7949.
Sn,C-2¢¢
Sn,C-2¢¢
SnCH CH CH CH ), 126.63 (C-5, C-6), 126.93 (C-4, C-7),
(
4) (Sylvestre) Julia olefinations with the sodium derivatives of
cyclopropylcarbinyl benzothiazolyl sulfone are a notable
exception showing solvent-dependent trans:cis ratios (78:22
in DMF – 9:91 in toluene or CH Cl ): Charette, A. B.; Lebel,
2
2
2
3
128.93 (C-1, C-10), 137.95 (half intensity, C-3, C-8), 151.69
2
2
117
1
19
(
flanked by Sn isotope satellites as 1 d, J
= J
Sn,C-2
Sn,C-2
2
2
117
1
19
and J
= J
= 10.9 Hz, C-2, C-9). The cis
Sn,C-9
Sn,C-9
5
2
2
6
configuration of the C =C double bond was proved by an
edited HSQC experiment (‘ H-coupled short-range H,C-
COSY’, 499.9/125.7 MHz, C D ): The C signal at
d = 126.63 (C-5/C-6), split by J
revealed the H,H coupling constants J5,4 = J5,6 and J6,7
=
J6,5 = 11.2 Hz. HRMS (EI, 70 eV): m/z = 681.26813 [M –
Bu], which is 3.89 ppm more than calcd for C H Sn
H. J. Am. Chem. Soc. 1996, 118, 10327.
1
(
(
(
5) Modified (Sylvestre) Julia olefinations with alkyl N-
phenyltetrazolyl sulfones: Blakemore, P. R.; Cole, W. J.;
Kocienski, P. J.; Morley, A. Synlett 1998, 26.
6) Modified (Sylvestre) Julia olefinations with alkyl N-tert-
butyltetrazolyl sulfones: Kocienski, P. J.; Bell, A.;
Blakemore, P. R. Synlett 2000, 365.
7) (a) Modified (Sylvestre) Julia olefinations with alkyl 2-
pyridyl sulfones: Charette, A. B.; Bethelette, C.; St-Martin,
D. Tetrahedron Lett. 2001, 42, 5149. (b) Corrigendum:
Charette, A. B.; Bethelette, C.; St-Martin, D. Tetrahedron
Lett. 2001, 42, 6619.
1
3
6
1
6
= 1J
= 155.8 Hz,
C-5,5-H
C-6,6-H
+
32 59
2
(
m/z = 681.26548).
(
(
14) Sorg, A. Dissertation; Universität Freiburg, 2004.
15) All new compounds gave satisfactory H NMR and 13C
1
NMR spectra and provided correct combustion analyses or
high resolution mass spectra.
16) (a) H O oxidation/Mo(VI) catalysis: Schultz, H. S.;
(
(8) Review: Blakemore, P. R. J. Chem. Soc., Perkin Trans. 1
2 2
Freyermuth, H. B.; Buc, S. R. J. Org. Chem. 1963, 28, 1140.
2
002, 2563.
9) Kende, A. S.; Mendoza, J. S. Tetrahedron Lett. 1990, 31,
105.
10) (a) Lankat, R. Diplomarbeit; Universität Würzburg, 1992,
3
b
(
b) H O oxidation/(NH ) Mo O catalysis: see ref.
(
2 2 4 6 7 24
(
(
17) Still, W. C.; Kahn, M.; Mitra, A. J. Org. Chem. 1978, 43,
923.
7
2
(
18) Cis:trans ratios up to >99:1 for (Sylvestre) Julia olefinations
of pentanal or octanal with (g-butylpropargyl)
25. (b) Lankat, R. Diplomarbeit; Universität Würzburg,
1
992, 28.
3
c
benzothiazolyl sulfone, LiBr, and LDA in THF: see ref.
19) Williams, D. R.; Clark, M. P. Tetrahedron Lett. 1999, 40,
291.
(
11) Vaz, B.; Alvarez, R.; de Lera, A. R. J. Org. Chem. 2002, 67,
040.
(
5
2
Synlett 2005, No. 2, 289–293 © Thieme Stuttgart · New York

LETTER
Stereoselective Synthesis of 1,3-Butadienyl- and 1,3,5-Hexatrienylstannanes
293
(
20) After terminating the present study, we learned that
(22) Kiehl, A.; Eberhardt, A.; Adam, M.; Enkelmann, V.; Müllen,
K. Angew. Chem., Int. Ed. Engl. 1992, 31, 1588; Angew.
Chem. 1992, 104, 1623.
Professor de Lera and associates observed cis-selective
(
Sylvestre) Julia olefinations, too, starting from a series of
polyenyl benzothiazolyl sulfones including sulfone 1f. In
their study, these authors (Vaz, B.; Alvarez, R.; Souto, J. A.;
de Lera, A. R. Synlett 2005, following paper) had
independently revised the stereochemical outcome of their
olefination 1f + 2 → 3 in favor of the selectivity depicted in
Scheme 1.
(23) Brückner, S.; Abraham, E.; Klotz, P.; Suffert, J. Org. Lett.
2002, 4, 3391.
(24) Lipshutz, B. H.; Lindsley, C. J. Am. Chem. Soc. 1997, 119,
4555.
(25) Siegel, K.; Brückner, R. Synlett 1999, 1227.
(26) Domon, L.; Uguen, D. Tetrahedron Lett. 2000, 41, 5501.
(27) Lipshutz, B. L.; Lee, J. I. Tetrahedron Lett. 1991, 32, 7211.
(28) Alvarez, R.; Herrero, M.; Lopez, S.; de Lera, A. R.
Tetrahedron 1998, 54, 6793.
(
21) Rzasa, R. M.; Shea, H. A.; Romo, D. J. Am. Chem. Soc.
1998, 120, 591.
Synlett 2005, No. 2, 289–293 © Thieme Stuttgart · New York