Selenylated dienes: synthesis, stereochemical studies by 77Se NMR, and transformation into functionalized allenes

Article abstract of DOI:10.1016/j.tet.2007.02.082

2-Phenylselanyl-1,3-dienes 3-8 were prepared by a Wittig or Wittig-Horner-Emmons procedure starting from α-phenylselanyl α,β-unsaturated aldehydes. Ratio and configuration of each diene isomers were determined by ⁷⁷Se and ¹H NMR. The

Full text of DOI:10.1016/j.tet.2007.02.082

Tetrahedron 63 (2007) 3707–3717
Selenylated dienes: synthesis, stereochemical studies by 77Se NMR,
and transformation into functionalized allenes
*
Sebastien Redon, Anne-Lise Berthe Berkaoui, Xavier Pannecoucke and Francis Outurquin
*
´
Universite et INSA de Rouen-LHO-IRCOF, UMR 6014 CNRS, 1, rue Tesniere, 76821 Mont Saint-Aignan Cedex, France
ꢀ
Received 17 January 2007; revised 19 February 2007; accepted 20 February 2007
Available online 23 February 2007
Abstract—2-Phenylselanyl-1,3-dienes 3–8 were prepared by a Wittig or Wittig–Horner–Emmons procedure starting from a-phenylselanyl
a,b-unsaturated aldehydes. Ratio and configuration of each diene isomers were determined by 77Se and 1H NMR. These dienes were then
oxidized into selenoxides, which could be isolated in some cases. In THF, [2,3]-sigmatropic rearrangement of allylic selenoxides, selenimides,
and dihalo-selenuranes occurred, yielding allenyl alcohols 12–15, allenyl carbamates 16c–19c, and 1-haloalkyl allenes 20c–22c, respectively.
Ó 2007 Elsevier Ltd. All rights reserved.
1. Introduction
Herein, we present a general access to 2-phenylselanyl-1,3-
dienes along with an unambiguous determination of the
stereochemistryby 77SeNMR. Dueto bothvinylic and allylic
position of the selanyl group in 2-phenylselanyl-1,3-dienes,
sigmatropic rearrangements of selenoxides, selenimides,
and dihalo-selenuranes were also studied, yielding, respec-
tively, allenic alcohols, carbamates, and 1-haloalkyl allenes.
The important place of the ‘selenium methodology’ in
organic synthesis is due to the easy introduction, transforma-
tion, and elimination of the selenylated group from organic
substrate that allow selective reactions under mild condi-
tions. Selenium reagents are now commonly used1–4 and
extensions to catalysts, ligands, asymmetric synthesis,5 and
radical chemistry6 were the subject of recent works.
2. Results and discussion
In particular, selenoxides play a pivotal role since the facile
oxidation of alkyl phenylselenides allows the preparation
of olefinic compounds and allylic alcohols under very mild
conditions.1,2 Our group was mainly involved in the studies
of the reactivity of selenylated carbonyl derivatives allowing
access to unsaturated, functionalized useful building-
blocks7 and their transformation into allenic alcohols via
oxidation of 2-phenylselanyl-1,3-dienes.8 These interesting
selenylated dienes could also act as useful intermediates
in organic synthesis, for example, as starting materials in
Diels–Alder cycloaddition.9,10 In the literature, very few
preparations of 1-arylselanyl-1,3-butadienes are described:
phenylselanyl alkylidene phosphoranes, phenylselanylalk-
enals11a or palladium-catalyzed cross coupling reactions.11b
A stereoselective synthesis of 1,3-dienyl selenides was re-
ported by reaction of a-arylselanylvinylstannanes with vinyl
halides11c or by means of a-alkenylzirconium complexes
with a-phenylselanylvinyl bromides.11d
Starting from a,b-unsaturated aldehydes 1, vinylic (Z)-a-
phenylselenoaldehydes 2 could be obtained as the unique
stereoisomers (except for compound 2c: Z/E 87/13) via
a selenenylation process using morpholinobenzeneselen-
amide (MBSe) followed by a silica gel ‘trap’.12 Compounds
2 were then transformed into 3-phenylselanyl-1,3-dienes
3–8 via classical Wittig (method A) or Wittig–Horner–
Emmons (method B) reactions8 (3–6 and 7–8, respectively)
(Scheme 1). For clarity reasons, the numbering of selenylated
dienes will be 3-phenylselanyl-1,3-dienes in the theoretical
R1
SePh
3
R1
SePh
CHO
R1
4
1. MBSe
2. SiO2
method A or B
2
1
CHO
R2
3: R2=H
1a: R1=Me
1b: R1=n-Pr
1c: R1=Ph
2
4: R2=Me
5: R2=Ph
Ph3P CHR2
O
method A :
method B :
6: R2=COCH3
7: R2=CN
Keywords: Selenium; Allenes; Oxidation; Conjugated dienes.
* Corresponding authors. Tel.: +33 (0)2 35 52 24 02; fax: +33 (0)2 35 52 29
59; e-mail addresses: xavier.pannecoucke@insa-rouen.fr; francis.
outurquin@univ-rouen.fr
(EtO) P CH2R2
, n-BuLi
2
8: R2=CO2Et
Scheme 1. Synthesis of 3-phenylselanyl-1,3-dienes.
0040–4020/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2007.02.082

3708
S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
Table 1. Synthesis of conjugated dienes 3–8
R1
R2
Yields (%) (Method A or B)a
1E,3Z
1Z,3Z
Entry
No.
1E,3E
SePh
R1
R1
SePh
SePh
E
Z
Z
4
R1
4
E
4
E
1
1
R2
2
2
Z
2
R2
R2
1
Ratio of each diastereomer after chromatography (before chromatography)
1
2
3
4
5
6
7
8
3a
3b
3c
4a
4b
4c
5a
5b
5c
6a
6b
6c
7a
7b
7c
8a
8b
8c
Me
Pr
Ph
Me
Pr
Ph
Me
Pr
Ph
Me
Pr
Ph
Me
Pr
Ph
Me
Pr
H
H
H
Me
Me
Me
Ph
Ph
Ph
COMe
COMe
COMe
CN
CN
CN
54 (A)
64 (A)
67 (A)
74 (A)
69 (A)
91 (A)
88 (A)
82 (A)
94 (A)
67 (A)
77 (A)
88 (A)
61 (B)
82 (B)
83 (B)
72 (B)
71 (B)
84 (B)
87
86
36
35 (20)
48 (20)
13
14
64
15 (0)
50 (80)
44 (80)
60 (70)c
10 (70)
10 (70)
45 (66)
8 (0)
40b (15)
20 (20)
20 (20)
70 (10)
70 (10)
55 (34)
80
80
55
68 (68)
68 (68)
48b (48)
80
9
10
11
12
13
14
15
16
17
18
20
20
45
10 (10)
10 (10)
20 (14)
20
20
16 (46)
20d (23)
20d (23)
30d (38)
CO2Et
CO2Et
CO2Et
80
0
Ph
84b (54)
a
See Scheme 1.
b
c
d
X-ray analysis could be obtained for this isomer.
15% of 1Z,3E isomer.
Traces of 1Z,3E isomer.
part, whereas official numbering will be applied in the
experimental part as numbering differs according to
substituents.
For all the ylides, we observed partial C3–C4 isomerization
as starting from Z selenylated enal 2, we always ended
up with C3–C4 E and Z isomers (NMR analysis of crude
material).
Only dienes 8 (R2¼CO2Et) and 5c (R1¼R2¼Ph) were al-
ready synthesized by our group.8 In this paper, we wanted
to extend this methodology to the preparation of various
functionalized dienes 6–7 and to less stabilized one 3–5.
The yields were ranging from 45% to 94% for method A
and from 61% to 84% for method B (Table 1). Indeed, the
creation of the C1–C2 double bond (see Scheme 1) gave of-
ten a mixture of Z/E diastereomers, some of them were not
stable and partial isomerization occurred during column
chromatography on silica gel.
Due to the complex mixture of diastereomers obtained in
the olefination reaction (C1–C2 and C3–C4 isomerizations
during the purification steps and the reaction time, respec-
tively), determination of the C3–C4 double bond configura-
tion became quickly a necessity (Table 1). Due to the
absence of hydrogen at C3 position and a H4 signal often
overlapped on Ar-H signals in 1H NMR spectra, determina-
tion of the configurations was very difficult even with
NOESY experiment. 77Se NMR appeared to be the easiest
and the more reliable method to answer this question. In-
deed with a single spectrum, we could determine the ratio
and the configuration of each selenylated diene isomers
(Table 2). When C1–C2 double bond is E, 77Se NMR
chemical shift is typical of diene configuration (1E,3E:
375.8<d<423.2; 1E,3Z: 251.8<d<308.5). In the same
Wittig reactions with non-stabilized ylides (R2¼Me) formed
predominantly Z isomer of the C1–C2 double bond (Table 1,
entries 4–6). C1–C2 configurations were easily determined
3
by measurement of JH1–H2 coupling constant (11.0–
12.0 Hz for Z and 14.6–15.6 Hz for E). With semi-stabilized
ylides (R2¼Ph, Table 1, entries 7–9), NMR spectrum of the
crude reaction shows three diastereomers, the major one
having Z configuration at C1–C2 double bond (70% for 5a
and 5b, 66% for 5c). In both cases, Z configuration for
C1–C2 double bond is not stable and isomerization occurred
during silica gel chromatography, modifying the diastereo-
mer ratio and rendering their separation difficult. Heating
of diastereomeric mixtures led to a complete transformation
of the C1–C2 Z isomer into the thermodynamically more
stable E isomer (entry 4: 1E,3Z/1E,3E: 70/30; entry 5:
1E,3Z/1E,3E: 76/24).
1
series, chemical shift of H2 in H NMR is always 0.3 ppm
lower for 3Z compared to 3E isomer. Configurations
1E,3Z of dienes 7c and 8c and 1E,3E of 4c were confirmed
by X-ray diffraction.
When C1–C2 double bond configuration is Z, the 77Se NMR
chemical shift (1Z,3Z: 348.5<d< 415.4) is difficult to com-
pare with C1–C2 E series. Indeed in the Z series, diene seems
to adopt S-cis conformation as opposed to the C1–C2 E
series (S-trans). This would be in total accordance with
a study of ‘Conformational thermodynamic and kinetic
parameters of methyl-substituted 1,3-butadienes’, which
showed the steric interactions in the 1,3-diene framework.14
Indeed in the C1–C2 Z series, strong interaction between
SePh and R2 under S-trans conformation forced the dienes
With stabilized ylides, Wittig or Wittig–Horner–Emmons
reactions afforded preferentially C1–C2 E isomer (6
R2¼COMe: 100%, 7 R2¼CN: 68–77%, 8 R2¼CO2Et: 100%).

S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
3709
Table 2. 77Se and 1H NMR data (ppm) of dienes 3–8
R1
R2
1Z,3Z
Entry
No.
1E,3Z
1E,3E
SePh
R1
SePh
R1
SePh
Z
Z
E
4
4
4
R1
E
E
1
1
2
Z
R2
2
2
R2
R2
1
77Se
1H (H-2)
77Se
1H (H-2)
77Se
1H (H-2)
1
2
3
4
5
6
7
8
3aa
3b
3ca
4a
4b
4c
5a
5b
5c
Me
Pr
Ph
Me
Pr
Ph
Me
Pr
Ph
Me
Pr
Ph
Me
Pr
Ph
Me
Pr
H
H
H
Me
Me
Me
Ph
Ph
Ph
COMe
COMe
COMe
CN
CN
CN
251.8
260.3
297.1
265.1
273.3
6.40
6.39
6.51
6.12
6.10
387.4
375.8
409.2
399.8
400.8
418.5
396.3
397.9
6.69
6.67
6.83
6.39
6.37
6.56
7.13
nd
362.7
369.2
411.0
368.6
374.9
415.4
5.80
5.82
5.86
6.14
6.16
6.18
261.7
269.8
304.0
267.4
275.6
308.5
252.7
260.7
288.2
263.6
271.5
301.1
7.01
6.97
nd
nd
7.22
nd
7.09
7.10
nd
7.41
7.41
7.55
9
10
11
12
13
14
15
16
17
18
6a
6b
6c
401.6
403.7
423.2
385.8
387.1
408.6
399.6
401.1
421.6
7.56
7.54
7.61
7.40
nd
7a
7b
7c
348.5
357.3
398.4
6.67
6.69
6.75
nd
8aa
8b
8c
CO2Et
CO2Et
CO2Et
7.72
7.70
7.80
Ph
The only sulfur analogues found in the literature confirm configurations and d 1H, 13C NMR of dienes 3a,13a 3c,13b and 8a.13c
a
to adopt a S-cis conformation. Unfortunately, due to mixture
and whatever the NOESY experimental parameters were,
we were unable to prove or disprove this assumption.
R1
SePh
Z
R1
SePh
O
SePh
4 E
Z
3
E
1
3
E
1
+
R1
minor
385.8<δ77Se<423.2
4
R2=COMe,
CN, CO2Et
2
2
R2
R2
2
major
252.7<δ77Se<308.5
The olefination reaction could be resumed as follows
(Scheme 2: with non- and semi-stabilized ylides; Scheme 3:
with stabilized ylides).
Scheme 3. Olefination reaction with stabilized ylides.
electrophile, allowing them to act as precursors for cyclo-
addition reactions.16 In particular, palladium-catalyzed
reactions of allenes have gained considerable attention in
recent years.17,18 Concerning their formation, allenes are of-
ten prepared via addition of organometallic reagents (essen-
tially cuprates) to enynes or to propargylic electrophiles via
an SN20 reaction.19 Several methods exist to prepare a-
hydroxyallenes: addition of lithiated allenes to aldehydes
or ketones;20,21 hydride reduction or Grignard addition
onto propargylic oxiranes;16,22 [2,3]-Wittig rearrangement
of propargyl ethers;23 insertion of alkenylidene carbenes
into the a C–H bond of alkoxides.24
With non- or semi-stabilized ylides, olefination reaction on
selenylated enal 2 was stereochemically controlled to yield
mainly 1Z isomer (Scheme 2). Under the reaction condi-
tions, partial C3–C4 isomerization occurred, delivering 3E
isomer. Due to structural steric instability (S-cis conforma-
tion), C1–C2 Z isomer isomerized to afford more stable 1E
isomers (Table 1: entries 4–9).
With stabilized ylides, as it could be predicted, the stereo-
chemistry of the created double bond C1–C2 was E: exclu-
sively when R2¼COMe or CO2Et (Table 1: entries 10–12,
16–18), as the major isomer with R2¼CN (Table 1: entries
13–15). Under the reaction conditions, as for non- or semi-
stabilized ylides, partial C3–C4 isomerization occurred,
delivering 3E isomer (Scheme 2).
We present a new and mild method that is compatible
with various chemical functionalities to prepare a-hydroxy-
allenes from selenylated 1,3-dienes after oxidation with
hydrogen peroxide. First experiments were performed with
stabilized 1,3-dienes 3c–8c derived from cinnamaldehyde.
The selenium atom at allylic position was first oxidized,
affording selenoxides, which further rearrange into a-hydr-
oxyallenes 12c–15c (Table 3). When R2 is an electron-
2.1. Allenes formation
Allenic compounds have been the subject of intensive
studies.15 Due to the versatile functionality of 1,2-diene
moiety, allenes could serve as either a nucleophile or an
Scheme 2. Olefination reaction with non- and semi-stabilized ylides.

3710
S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
Table 3. a-Hydroxyallenes’ synthesis
hydroxyallenes via [1,3]-sigmatropic rearrangement of al-
lylic selenoxides. For this, our group8 has already shown
that when R2 is COOEt, the yield was much better when
R1 is an aryl than an alkyl group (Table 4: compounds
15a–c).
Ph
Ph
Ph
SePh
H2O2
THF
Et3N, Δ
Ph
Se
O
R2
CH2Cl2, r.t.
HO
12c-15c
R2
R2
9c-11c
3c-8c
Starting dienes R2
Complementary results showed that when R1 is an alkyl or
phenyl group regardless of the nature of R2: methyl or
phenyl, the a-hydroxyallenes 13 and 14 could be obtained
with good yields (see Table 4). Furthermore, yields were
always higher when R1 changed by following the order
phenyl>propyl>methyl. In all the cases cited above, two
diastereomers of allene were detected by 13C NMR. Further
studies are still undertaken to try to understand and to
explain the stereoselectivity.
Selenoxides (yield %) Allenes (yield %)
3c
4c
5c
6c
7c
8c
H
Me
Ph
COCH3
CN
CO2Et
—
—
—
9c (81)
10c (63)
11c (76)
12c (78)
13c (81)
14c (81)
—
—
15c (75)
withdrawing group, the moderately stable selenoxides could
be isolated as a mixture of diastereomers (Table 3:
compounds 9c, 10c, and 11c). The stereochemistry of these
selenoxides was impossible to attribute due to complex NMR
spectra (as starting dienes were also mixture of isomers, vide
supra) and instability of the products.
Due to their pharmaceutical interests (anesthetic, hypnotic,
enzyme inhibitors28 or treatment of depression29), numerous
methods for the preparation of allenic carbamates are de-
scribed in the literature,15–18 but none of them have exploited
the mildnessand the selectivityof organoseleniumchemistry.
Hopkins and co-workers30 studied the [2,3]-sigmatropic re-
arrangement of allylic selenimides and nitrogen analogues
of selenoxides. Thus, N-allyl carbamates were prepared by
oxidation with anhydrous N-chlorosuccinimide (NCS) in
methanol in the presence of tert-butyl carbamate.
In all cases, the rearrangement into a-hydroxyallenes was
conducted in THF in the presence of triethylamine at room
temperature to give compounds 12c–15c in good yields
(Table 3). For compound 12c,25 only one diastereomer was
detected by 13C NMR, but two isomers are present in the
case of allenes 13c (63/37), 14c8 (70/30), and 15c8 (70/30).
Noteworthy the [1,3]-sigmatropic rearrangement of conju-
gated dienes is specific to selenoxides, no rearrangement
occurred with sulfoxides. However, when R2 was a carbonyl
or a nitrile group, the selenoxides 9c and 10c decomposed,
whatever the conditions, and we were unable to isolate
allenes.
We applied this reaction to dienes 3c, 4c, 5c, and 8c (Scheme
4). After oxidation by N-chlorosuccinimide in the presence
of tert-butyl carbamate, rearrangement of the selenimide
followed by hydrolysis of the intermediate selenamide, we
ended up, respectively, with allenic carbamates 16c, 17c,
18c, and 19c (in 43–53% yields). It is significant to note
that traces of water can induce partial hydrolysis of the selen-
imide, being able to lead to the formation of corresponding
After variation of R2 group, we studied the influence of
R1 group on the transformation of 1,3-dienes into a-
1
hydroxyallene. H and 13C NMR studies showed the pres-
ence of only one diastereomer presumably due to an overlap
of the chemical shifts of the two expected diastereomers.
Table 4. a-Hydroxyallenes’ synthesis: influence of R1 group
R1
R1
4
SePh
1. H2O2
Finally, tocompletethestudiesconcerningthetransformation
of easily accessible 3-selenylated-1,3-dienes into various a-
functionalized allenes species, chlorination and bromination
of selenylated conjugated dienes were undertaken (Scheme
4). Dihalogenated adducts, obtained from halogenation of
conjugated dienes, were decomposed in CCl4 under reflux,
yieldinga-halogenatedallenes. Theallenescouldbe obtained
only, if ethylvinylether, a PhSeX trap, is present in the reac-
tion mixture. This additive is necessary to shift the equilib-
rium to the formation of allenes.
3
1
R2
2. Et3N, THF
2
HO
R2
R1
Starting dienes
R2
Allenes (yield %)
4a
4b
4c
5a
5b
5c
8a
8b
8c
Me
n-Pr
Ph
Me
n-Pr
Ph
Me
n-Pr
Ph
Me
Me
Me
Ph
Ph
Ph
CO2Et
CO2Et
CO2Et
13a26 (51)
13b (63)
13c (81)
14a27 (38)
14b (67)
14c8 (81)
15a8 (30)
15b8 (30)
15c8 (75)
In conclusion, we have developed a general access to 2-
phenylselanyl-1,3-dienesandanunambiguousdetermination
Ph
.
Ph
SePh
R2
Ph
.
H2NCO2t-Bu, 0°C
X
NHCO2t-Bu
NCS, NEt3, MeOH
SOCl2 or Br2
R2
R2
20c31 (X=Cl, 58%)
3c R2=H
16c(53%)
17c(48%)
18c(43%)
19c(51%)
21c (X=Cl, 87%); 22c (X=Br, 61%) 4c R2=Me
5c R2=Ph
8c R2=CO2Et
Scheme 4. Allenyl carbamates and 1-halogenoalkyl allenes syntheses.31

S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
3711
of the stereochemistry of the two double bonds based on 77Se
NMR. These dienes, due to both vinylic and allylic position
of selanyl group could be transformed via [1,3]-sigmatropic
rearrangements into variously functionalized allenes.
1H NMR d (ppm) 7.18–7.26 (m, 3H), 7.38–7.44 (m, 5H),
7.84–7.88 (m, 2H), 8.01 (s, 1H, H-3), 9.50 (s, 1H, H-1);
13C NMR d (ppm) 127.4, 128.6, 129.4, 131.0, 131.2,
132.1, 132.5 (C-2), 152.6 (C-3), 191.6 (C-1). (E)-isomer:
1
oil, 77Se d (ppm) 409.5; H NMR d (ppm) 7.18–7.24 (m,
This transformation occurred via selenoxide, selenimide or
halo-selenurane intermediates under mild and selective
conditions that give access to even none stabilized a-
hydroxy, a-amino or a-halogenoallenes.
3H), 7.32 (s, 1H, H-3), 7.34–7.42 (m, 5H), 7.64–7.69 (m,
2H), 9.79 (s, 1H, H-1); 13C NMR d (ppm) 126.6, 128.7,
129.1, 129.4, 129.6, 129.9, 134.8, 136.5, 138.5 (C-2),
145.5 (C-3), 189.1 (C-1).
3.1.2. Preparation of 3-phenylselanyl-1,3-dienes 3. At
room temperature, a solution of n-BuLi in hexanes (1.6 M,
3.45 ml, 5.5 mmol) was slowly added, under argon, to
methyltriphenylphosphonium bromide (1.96 g, 5.5 mmol)
in anhydrous THF (30 ml). After stirring for 0.5 h, a-phenyl-
selanyl enal 2 (5 mmol) in THF (5 ml) was added dropwise.
The mixture was stirred for 3 h under reflux, quenched with
saturated aqueous NH4Cl, and extracted with diethylether.
The organic extracts were dried over magnesium sulfate
and concentrated under vacuum. The residue was purified
by chromatography on silica gel (light petroleum) and recti-
fied by Kugelrhor distillation.
3. Experimental
3.1. General
Solvents were purified by conventional methods prior to use.
TLC was performed on Merck 60F-250 silica gel plates and
column chromatography over silica gel SI 60 (230–240
mesh). Melting points were taken on a Kofler apparatus
and were uncorrected. Elemental analyses were carried out
on a Carlo Erba EA 1100 analyzer and mass spectra on
a HP5890 (electronic impact 70 eV) using GC–MS coupled
with a Jeol AX 500. NMR spectra were recorded on a Bruker
DPX 300 spectrometer operating at 300 MHz for proton and
75.4 MHz for carbon. This probe is equipped with pulsed-
field (z) gradients. 77Se NMR spectra were recorded at
21 ꢀC on a Bruker DPX 400 spectrometer operating at
3.1.2.1. 3-Phenylselanylpent-1,3-diene 3a. Yield 54%,
1
Z/E 87/13. (Z)-isomer: oil, 77Se d (ppm) 251.8; H NMR
d (ppm) 2.00 (d, 3H, J¼6.7 Hz, H-5), 5.06 (d, Hcis,
J¼10.2 Hz), 5.59 (d, Htrans, J¼16.5 Hz), 6.32 (q, 1H,
J¼6.7 Hz, H-4), 6.40 (dd, 1H, J¼10.2, 16.5 Hz, H-2),
7.10–7.32 (m, 5H); 13C NMR d (ppm) 18.4 (Me), 117.1
(C-1), 125.9, 129.1, 129.3, 129.9, 131.6 (C-3), 138.5
(C-2), 138.8 (C-4). Anal. Calcd for C11H12Se: C, 59.20; H,
5.42. Found: C, 58.96; H, 5.37. (E)-isomer: oil, 77Se
77
76.29 MHz for Se, using a pulse length of 19 ms (90ꢀ
pulse¼19 ms) and an optimized relaxation delay of 2 s. An
average of 1500 scans for 77Se NMR was necessary to
have reliable information. Chemical shifts (d) are expressed
in ppm relative to TMS for 1H and 13C nuclei and to Me2Se
for 77Se nuclei; coupling constants (J) are given in Hertz;
coupling multiplicities are reported using conventional
abbreviations.
1
d (ppm) 387.4; H NMR d (ppm) 1.91 (d, 3H, J¼7.2 Hz,
H-5), 5.23 (d, Hcis, J¼10.8 Hz), 5.64 (d, Htrans
,
J¼16.7 Hz), 6.02 (q, 1H, J¼6.7 Hz, H-4), 6.69 (dd, 1H,
J¼10.8, 16.7 Hz, H-2), 7.10–7.32 (m, 5H); 13C NMR
d (ppm) 18.0 (Me), 119.9 (C-1), 127.8, 129.1, 129.3,
131.2, 131.6 (C-3), 137.1 (C-2), 137.9 (C-4).
3.1.1. Preparation of a-phenylselanyl enals 2. A solution
of enal 1 (10 mmol) in anhydrous dichloromethane (50 ml)
was added dropwise to the solution of N-phenylselanylmor-
pholine12a (1.8 g, 20 mmol), in the same solvent (20 ml).
The mixture was stirred for 6 h at room temperature and
then hydrolyzed by 1 N HCl solution (15 ml). The aqueous
layer was extracted with dichloromethane (3ꢁ50 ml) and
the organic fractions were dried and concentrated. The
a-phenylselanyl enals 2 were purified by chromatography
on silica gel (elution with a mixture of petroleum ether/
CH2Cl2: 85/15).
3.1.2.2. 3-Phenylselanylhept-1,3-diene 3b. Yield 64%,
1
Z/E 86/14. (Z)- isomer: oil, 77Se d (ppm) 260.3; H NMR
d (ppm) 0.91 (t, 3H, J¼7.4 Hz), 1.45 (m, 2H), 2.45 (q,
2H, J¼7.4 Hz), 5.06 (d, Hcis, J¼10.4 Hz), 5.57 (d, Htrans
,
J¼16.6 Hz), 6.26 (t, 1H, J¼7.1 Hz, H-4), 6.39 (dd, 1H,
J¼10.4, 16.6 Hz, H-2), 7.10–7.32 (m, 5H); 13C NMR
d (ppm) 14.0 (Me), 22.6 (C-6), 34.6 (C-5), 117.3 (C-1),
125.9, 127.8, 129.1, 129.3, 131.3 (C-3), 131.6, 138.4
(C-2), 144.3 (C-4). Anal. Calcd for C13H16Se: C, 62.15; H,
6.42. Found: C, 62.33; H, 6.26. (E)-isomer: oil, 77Se
3.1.1.1. (Z)-2-Phenylselanylbut-2-enal 2a. Yield 85%,
1
1
oil, 77Se d (ppm) 261.0; H NMR d (ppm) 2.18 (d, 3H,
d (ppm) 375.8; H NMR d (ppm) 1.01 (t, 3H, J¼7.4 Hz),
J¼6.7 Hz), 7.20–7.27 (m, 3H), 7.32–7.40 (m, 3H), 9.41 (s,
1H, H-1); 13C NMR d (ppm) 19.1, 127.1, 129.3, 129.5,
129.6, 131.8, 135.3, 137.3 (C-2), 158.0 (C-3), 190.9 (C-1).
1.55 (m, 2H), 2.45 (q, 2H, J¼7.4 Hz), 5.22 (d, Hcis,
J¼10.3 Hz), 5.63 (d, Htrans, J¼16.6 Hz), 6.03 (t, 1H,
J¼7.1 Hz, H-4), 6.67 (dd, 1H, J¼10.3, 16.6 Hz, H-2),
7.10–7.32 (m, 5H); 13C NMR d (ppm) 14.0 (Me), 22.7
(C-6), 34.4 (C-5), 120.0 (C-1), 125.9, 127.8, 129.1, 129.3,
131.2 (C-3), 140.9 (C-2), 143.9 (C-4).
3.1.1.2. (Z)-2-Phenylselanylhex-2-enal 2b. Yield 83%,
1
oil, 77Se d (ppm) 268.5; H NMR d (ppm) 0.97 (t, 3H,
J¼7.4 Hz), 1.55 (m, 2H), 2.60 (q, 2H, J¼7.2 Hz), 7.20–7.29
(m, 3H), 7.26 (t, 1H, J¼7.2 Hz, H-3), 7.37–7.41 (m, 2H),
9.40 (s, 1H, H-1); 13C NMR d (ppm) 14.0, 21.7, 34.8, 127.1,
129.3, 129.8, 131.9, 136.1 (C-2), 162.5 (C-3), 191.0 (C-1).
3.1.2.3. 1-Phenyl-2-phenylselanylbut-1,3-diene 3c.
Yield 67%, Z/E 36/64. (Z)-isomer: oil, 77Se d (ppm) 297.1;
1H NMR d (ppm) 5.20 (d, Hcis, J¼10.2 Hz), 5.70 (d, Htrans
,
J¼16.6 Hz), 6.51 (ddd, 1H, J¼0.8, 10.2, 16.6 Hz, H-3),
7.15 (s, 1H, H-1), 7.25–7.40 (m, 8H), 7.60 (m, 2H); 13C
NMR d (ppm) 119.2 (C-4), 126.4, 127.3, 127.7, 128.3,
3.1.1.3. 3-Phenyl-2-phenylselanylprop-2-enal 2c. Yield
88%, Z/E 87/13. (Z)-isomer: mp¼64 ꢀC, 77Se d (ppm) 301.1;

3712
S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
129.3, 129.4, 130.2, 132.7, 139.2 (C-3), 139.5, 140.9 (C-1).
(E)-isomer: oil, 77Se d (ppm) 409.2; 1H NMR d (ppm) 5.34
(dd, Hcis, J¼1.3, 10.5 Hz), 5.80 (d, Htrans, J¼16.6 Hz), 6.83
(ddd, 1H, J¼1.0, 10.5, 16.6 Hz, H-3), 7.05 (s, 1H, H-1),
7.25–7.40 (m, 8H), 7.50 (m, 2H); 13C NMR d (ppm) 121.4
(C-4), 126.4, 127.7, 128.1, 128.5, 129.4, 130.1, 130.6,
132.7, 133.2 (C-3), 137.5 (C-1). Anal. Calcd for C16H14Se:
C, 67.37; H, 4.90. Found: C, 66.97; H, 4.83.
H-4), 5.79 (d, 1H, J¼11.3 Hz, H-3), 6.78 (s, 1H, H-1),
7.18–7.35 (m, 8H), 7.50–7.55 (m, 2H); 13C NMR d (ppm)
14.5, 127.6 (C-4), 127.8, 128.3, 128.4, 128.9, 129.2, 129.3,
129.9 (C-2), 132.2 (C-3), 132.9 (C-1), 137.4. (1E,3Z)-
1
isomer: oil, 77Se d (ppm) 309.0; H NMR d (ppm) 1.38
(dd, 3H, J¼1.5, 7.2 Hz), 5.43 (m, 1H, H-4), 6.04 (d, 1H,
J¼11.3 Hz, H-3), 6.72 (s, 1H, H-1), 7.18–7.35 (m, 8H),
7.50–7.55 (m, 2H). (1E,3E)-isomer: first eluted, mp¼47 ꢀC,
77Se d (ppm) 418.5; 1H NMR d (ppm) 1.70 (dd, 3H, J¼0.8,
6.7 Hz), 6.25 (m, 1H, H-4), 6.48 (d, 1H, J¼14.6 Hz, H-3),
6.77 (s, 1H, H-1), 7.25–7.36 (m, 8H), 7.49–7.54 (m, 2H);
13C NMR d (ppm) 18.5 (C-5), 126.6, 127.2, 127.8 (C-3),
128.4, 129.2, 129.4, 131.0, 132.3 (C-2), 132.7, 133.9
(C-4), 134.6 (C-1), 137.4. Anal. Calcd for C17H16Se: C,
68.23; H, 5.39. Found: C, 68.11; H, 5.35.
3.1.3. Preparation of selenides 4. The general procedure
was used with the following modification. The reaction
was carried out with ethyltriphenylphosphonium bro-
mide. The selenide 4 was obtained after chromatography
on silica gel (light petroleum) and rectification by Kugelrhor
distillation.
3.1.3.1. 3-Phenylselanylhex-2,4-diene 4a. Yield 74%.
3.1.4. Preparation of dienes 5. A solution of n-BuLi in
hexanes (1.6 M, 3.45 ml, 5.5 mmol) was slowly added,
under argon, to benzyltriphenylphosphonium chloride
(2.13 g, 5.5 mmol) in anhydrous THF (50 ml). After stirring
for 1 h at room temperature, a-phenylselanyl enal 2
(5 mmol) in THF (5 ml) was added dropwise. The mixture
was stirred for 3 h at room temperature, quenched with
saturated aqueous NH4Cl, and extracted with diethylether.
The organic extracts were dried over magnesium sulfate
and concentrated under vacuum. The residue was purified
by chromatography on silica gel (light petroleum/CH2Cl2:
80/20).
1
(2Z,4Z)-isomer: oil, 77Se d (ppm) 362.7; H NMR d (ppm)
1.73 (d, 3H, J¼6.9 Hz, H-6), 1.96 (d, 3H, J¼6.7 Hz, H-1),
5.40 (qd, J¼6.9, 11.2 Hz, 1H, H-5), 5.83 (d, 1H,
J¼11.2 Hz, H-4), 5.97 (q, 1H, J¼6.7 Hz, H-2), 7.10–7.25
(m, 5H); 13C NMR d (ppm) 14.3, 17.8, 125.7, 126.7,
128.9, 129.1, 130.9, 131.6, 132.7, 133.3. Anal. Calcd for
C12H14Se: C, 60.76; H, 5.95. Found: C, 60.68; H, 5.92.
1
(2E,4Z)-isomer: oil, 77Se d (ppm) 335.5; H NMR d (ppm)
1.55 (dd, 3H, J¼1.5, 6.9 Hz, H-6), 1.67 (dd, 3H, J¼1.3,
6.9 Hz, H-1), 5.51 (m, 1H, H-5), 5.83 (d, 1H, J¼13.0 Hz,
H-4), 6.17 (m, 1H, H-2), 7.10–7.25 (m, 5H). (2E,4E)-isomer:
1
oil, 77Se d (ppm) 399.8; H NMR d (ppm) 1.78 (dd, 3H,
J¼0.8, 6.7 Hz, H-6), 1.88 (d, 3H, J¼7.7 Hz, H-1), 6.10
(m, 1H, H-5), 6.39 (d, 1H, J¼15.1 Hz, H-4), 7.10–7.25 (m,
4H), 7.57–7.63 (m, 2H); 13C NMR d (ppm) 15.3, 18.4,
126.1, 126.3, 128.9, 129.3, 131.0, 132.0, 133.3, 134.7.
3.1.4.1. 1-Phenyl-3-phenylselanylpent-1,3-diene 5a.
1
Yield 88%. (1Z,3Z)-isomer: oil, 77Se d (ppm) 368.6; H
NMR d (ppm) 1.79 (dd, 3H, J¼1.6, 6.9 Hz), 5.93–6.04 (m,
2H, H-1, H-4), 6.14 (d, 1H, J¼12.0 Hz, H-2), 7.10–7.60
(m, 10H); 13C NMR d (ppm) 17.5, 126.8, 128.6, 128.7,
129.3, 129.8, 131.1 (C-2), 131.8 (C-1), 138.1 (C-3), 138.9
1
(2Z,4E)-isomer: oil, 77Se d (ppm) 265.1; H NMR d (ppm)
1.72 (d, 3H, J¼5.2 Hz, H-6), 1.97 (d, 3H, J¼6.9 Hz, H-1),
6.05–6.16 (m, 2H, H-4, H-5), 6.18 (q, 1H, J¼6.9 Hz, H-2),
7.10–7.25 (m, 3H), 7.57–7.63 (m, 2H); 13C NMR d (ppm)
17.9, 18.3, 125.7, 127.8, 129.1, 129.7, 130.9, 131.6, 133.0,
135.5.
1
(C-4). (1E,3Z)-isomer: oil, 77Se d (ppm) 261.7; H NMR
d (ppm) 2.07 (d, 3H, J¼6.9 Hz), 6.45 (q, 1H, J¼6.9 Hz, H-
4), 6.85 (d, 1H, J¼15.5 Hz, H-1), 7.01 (d, 1H, J¼15.5 Hz,
H-2), 7.10–7.45 (m, 10H); 13C NMR d (ppm) 18.7, 126.8,
128.6, 128.7, 129.3, 129.8, 131.1 (C-2), 131.6 (C-1), 137.4
(C-3), 139.0 (C-4). Anal. Calcd for C17H16Se: C, 68.23; H,
5.39. Found: C, 68.54; H, 5.62. (1E,3E)-isomer: oil, 77Se
3.1.3.2. 4-Phenylselanyloct-2,4-diene 4b. Yield 69%.
1
(2Z,4Z)-isomer: oil, 77Se d (ppm) 369.2; H NMR d (ppm)
1
0.97 (t, 3H, J¼7.4 Hz, H-8), 1.51 (m, 2H, H-7), 1.74 (dd,
3H, J¼1.8, 6.9 Hz, H-1), 2.37 (m, 2H, H-6), 5.41 (m, 1H,
H-2), 5.82 (d, 1H, J¼11.5 Hz, H-3), 5.90 (t, 1H, J¼7.2 Hz,
H-5), 7.10–7.30 (m, 3H), 7.35–7.42 (m, 2H); 13C NMR
d (ppm) 14.0, 14.3 (C-1), 22.7, 34.2, 126.6 (C-2), 127.9,
128.9, 129.3, 131.0 (C-4), 131.6, 131.9 (C-3), 137.85 (C-
5). Anal. Calcd for C14H18Se: C, 63.39; H, 6.84. Found: C,
63.13; H, 6.94. (2E,4Z)-isomer: oil, 77Se d (ppm) 273.3;
1H NMR d (ppm) 0.90 (t, 3H, J¼7.4 Hz), 1.43 (m, 2H),
1.71 (d, 3H, J¼5.4 Hz), 2.40 (m, 2H), 6.01–6.17 (m, 3H),
7.10–7.30 (m, 3H), 7.58–7.62 (m, 2H); 13C NMR d (ppm)
14.0, 18.0 (C-1), 22.6, 34.4, 125.7 (C-3), 128.0, 129.3,
131.6, 133.0 (C-2), 141.1 (C-5). (2E,4E)-isomer: oil, 77Se
d (ppm) 396.6; H NMR d (ppm) 2.02 (d, 3H, J¼7.3 Hz),
6.38 (q, 1H, J¼7.3 Hz, H-4), 7.03 (d, 1H, J¼15.5 Hz, H-
1), 7.13 (d, 1H, J¼15.5 Hz, H-2), 7.15–7.60 (m, 10H); 13C
NMR d (ppm) 15.7, 126.0, 128.7, 129.3, 129.8, 130.9
(C-2), 131.6, 132.8 (C-1), 137.2 (C-3), 138.2 (C-4).
3.1.4.2. 1-Phenyl-3-phenylselanylhept-1,3-diene 5b.
1
Yield 82%. (1Z,3Z)-isomer: 77Se d (ppm) 374.9; H NMR
d (ppm) 0.87 (t, 3H, J¼7.4 Hz), 1.37 (m, 2H), 2.24 (m,
2H), 5.96 (t, 1H, J¼7.2 Hz, H-4), 5.98 (d, 1H, J¼12.0 Hz,
H-1), 6.16 (d, 1H, J¼12.0 Hz, H-2), 7.10–7.60 (m, 10H);
13C NMR d (ppm) 14.0, 21.9, 33.9, 124.0, 126.7, 128.7,
129.3, 129.8, 130.7, 131.1, 132.2, 137.3 (C-3), 144.5
(C-4). (1E,3Z)-isomer: 77Se d (ppm) 269.8; 1H NMR
d (ppm) 0.91 (t, 3H, J¼7.4 Hz), 1.44 (m, 2H), 2.47 (m,
2H), 6.35 (t, 1H, J¼7.4 Hz, H-4), 6.82 (d, 1H, J¼15.4 Hz,
H-1), 6.97 (d, 1H, J¼15.4 Hz, H-2), 7.10–7.60 (m, 10H);
13C NMR d (ppm) 14.1, 22.6, 34.8, 124.0, 126.7, 128.7,
129.3, 129.8, 130.7 (C-2), 131.1, 132.2 (C-1), 137.4 (C-3),
144.6 (C-4). Anal. Calcd for C19H20Se: C, 69.72; H, 6.16.
Found: C, 69.54; H, 5.92. (1E,3E)-isomer: 77Se d (ppm)
1
d (ppm) 400.8; H NMR d (ppm) 0.95 (t, 3H, J¼7.4 Hz),
1.45 (m, 2H), 1.77 (d, 3H, J¼6.4 Hz), 2.29 (m, 2H), 6.02–
6.18 (m, 1H), 6.38 (d, 1H, J¼14.8 Hz), 7.15–7.30 (m, 4H),
7.58–7.62 (m, 2H).
3.1.3.3. 1-Phenyl-2-phenylselanylpent-1,3-diene 4c.
1
Yield 91%. (1Z,3Z)-isomer: oil, 77Se d (ppm) 411.0; H
NMR d (ppm) 1.77 (dd, 3H, J¼1.5, 6.9 Hz), 5.40 (m, 1H,

S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
3713
1
397.9; H NMR d (ppm) 0.96 (t, 3H, J¼7.4 Hz), 1.51 (m,
2H); 13C NMR d (ppm) 28.5 (C-1), 126.8 (C-3), 127.9,
128.0, 128.2, 129.4, 130.4, 131.1, 132.6, 134.4, 136.0
(C-5), 146.4 (C-6), 146.8 (C-4), 198.4 (C-2). Anal. Calcd
for C18H16OSe: C, 66.06; H, 4.93. Found: C, 65.90; H, 4.86.
2H), 2.39 (m, 2H), 6.30 (t, 1H, J¼7.4 Hz, H-4), 7.05 (d,
1H, J¼15.4 Hz, H-1), 7.10–7.60 (m, 11H); 13C NMR
d (ppm) 14.0, 22.6, 31.9, 124.0, 126.7, 128.7, 129.3, 129.8,
130.8 (C-2), 131.1, 132.2 (C-1), 137.7 (C-3), 144.3 (C-4).
3.1.6. Preparation of penta-2,4-dienenitriles 7. A solution
of n-BuLi in hexanes (1.6 M, 3.45 ml, 5.5 mmol) was slowly
added, under argon, to cyanomethyldiethylphosphonoace-
tate (0.97 g, 5.5 mmol) in anhydrous THF (50 ml) at 0 ꢀC.
After stirring for 0.5 h at room temperature, the solution
was cooled to ꢂ78 ꢀC. Then, a-phenylselanyl enal 2
(5 mmol) in THF (5 ml) was added dropwise at this temper-
ature. The mixture was stirred for 2 h at ꢂ78 ꢀC for 7a
and 7b or 12 h for 7c, quenched with saturated aqueous
NH4Cl, and extracted with diethylether. The organic extracts
were dried over magnesium sulfate and concentrated under
vacuum. The residue was purified by chromatography on
silica gel (light petroleum/CH2Cl2: 70/30).
3.1.4.3.
1,4-Diphenyl-2-phenylselanylbut-1,3-diene
5c.8 Yield 94%. (1Z,3Z)-isomer: 77Se d (ppm) 415.4; H
NMR d (ppm) 5.98 (dd, 1H, J¼1.5, 12.0 Hz, H-4), 6.18 (d,
1H, J¼12.0 Hz, H-3), 6.92 (d, 1H, J¼1.5 Hz, H-1), 7.15–
7.60 (m, 15H); 13C NMR d (ppm) 126.9, 127.2, 127.7,
128.1, 128.5, 128.7, 128.8, 129.4, 129.5, 130.5 (C-3),
130.9 (C-1), 131.8 (C-4), 133.7, 134.0, 136.0, 137.7 (C-2).
1
(1Z,3E)-isomer:12 77Se d (ppm) 304.0; H NMR d (ppm)
7.00 (d, 1H, J¼15.4 Hz, H-4), 7.15–7.60 (m, 17H).
1
3.1.5. Preparation of dienic methylketones 6. A solution of
a-phenylselanyl enal 2 (5 mmol) and 1-triphenylphosphor-
anylidene propanone (1.75 g, 5.5 mmol) in chloroform
(30 ml) was stirred at room temperature for 48 h (6a) or
60 h (6c). After concentration under reduced pressure, the
residue was purified by silica gel chromatography (light
petroleum/CH2Cl2: 70/30).
3.1.6.1. 4-Phenylselanylhex-2,4-dienenitrile 7a. Yield
61%. (2E,4Z)-isomer: 77Se d (ppm) 252.7; 1H NMR
d (ppm) 2.13 (d, 3H, J¼6.9 Hz, H-6), 5.84 (d, 1H,
J¼15.6 Hz, H-2), 6.69 (q, 1H, J¼6.9 Hz, H-5), 7.09 (d,
1H, J¼15.7 Hz, H-3), 7.17–7.25 (m, 5H); 13C NMR
d (ppm) 19.3, 99.7 (C-2), 118.3 (C-1), 126.7, 129.4, 129.9,
130.6, 132.0, 148.6 (C-5), 152.1 (C-3). Anal. Calcd for
C12H11NSe: C, 58.07; H, 4.47. Found: C, 58.13; H, 4.58.
(2E,4E)-isomer: 77Se d (ppm) 385.8; 1H NMR d (ppm)
2.04 (d, 3H, J¼7.4 Hz, H-6), 5.89 (d, 1H, J¼15.6 Hz, H-
2), 6.77 (q, 1H, J¼7.3 Hz, H-5), 7.42 (d, 1H, J¼15.6 Hz,
H-3), 7.17–7.25 (m, 5H); 13C NMR d (ppm) 16.1, 102.4,
118.3, 126.7, 129.3, 129.8, 132.0, 144.4, 151.8. (2Z,4Z)-iso-
3.1.5.1. 5-Phenylselanylhepta-3,5-dien-2-one 6a. Yield
67%. (3E,5Z)-isomer: 77Se d (ppm) 267.4; 1H NMR d (ppm)
2.11 (d, 3H, J¼6.9 Hz, H-7), 2.23 (s, 3H, H-1), 6.58 (d, 1H,
J¼15.2 Hz, H-3), 6.75 (q, 1H, J¼6.9 Hz, H-6), 7.10–7.30
(m, 6H); 13C NMR d (ppm) 19.2 (C-7), 28.4 (C-1), 126.8,
129.2, 129.8 (C-3), 131.0, 134.4, 136.9 (C-5), 145.3 (C-4),
148.0 (C-6), 198.3 (C-2). Anal. Calcd for C13H14OSe: C,
58.87; H, 5.32. Found: C, 58.51; H, 5.15. (3E,5E)-isomer:
77Se d (ppm) 401.6; 1H NMR d (ppm) 2.04 (d, 3H,
J¼7.4 Hz, H-7), 2.25 (s, 3H, H-1), 6.59 (d, 1H,
J¼15.2 Hz, H-3), 6.71 (q, 1H, J¼7.4 Hz, H-6), 7.10–7.30
(m, 5H), 7.56 (d, 1H, J¼15.2 Hz, H-4).
1
mer: 77Se d (ppm) 348.5; H NMR d (ppm) 2.10 (dd, 3H,
J¼0.9, 6.9 Hz, H-6), 5.09 (d, 1H, J¼11.4 Hz, H-2), 6.69
(dd, 1H, J¼0.9, 11.4 Hz, H-3), 6.76 (qd, 1H, J¼0.9,
7.3 Hz, H-5), 7.19–7.25 (m, 3H), 7.38–7.45 (m, 2H); 13C
NMR d (ppm) 18.4, 96.7 (C-2), 116.6 (C-1), 126.4, 127.4,
129.3, 129.7, 140.4, 147.5. (2Z,4E)-isomer: 77Se d (ppm)
304.5; 1H NMR d (ppm) 1.94 (dd, 3H, J¼1.0, 7.2 Hz,
H-6), 5.25 (d, 1H, J¼11.2 Hz, H-2), 6.70 (dd, 1H, J¼0.9,
11.2 Hz, H-3), 6.55 (qd, 1H, J¼1.0, 7.2 Hz, H-5), 7.19–
7.25 (m, 3H), 7.38–7.45 (m, 2H).
3.1.5.2. 5-Phenylselanylnona-3,5-dien-2-one 6b. Yield
77%. (3E,5Z)-isomer: 77Se d (ppm) 275.6; 1H NMR
d (ppm) 0.93 (t, 3H, J¼7.4 Hz, H-9), 1.49 (m, 2H, H-8),
2.23 (s, 3H, H-1), 2.52 (m, 2H, H-7), 6.56 (d, 1H,
J¼15.1 Hz, H-3), 6.67 (t, 1H, J¼7.2 Hz, H-6), 7.10–7.35
(m, 6H, H-4, Ph); 13C NMR d (ppm) 13.9 (C-9), 22.1 (C-
8), 28.5 (C-1), 35.3 (C-7), 126.4, 129.5, 129.9 (C-3), 136.8
(C-5), 145.5 (C-4), 153.5 (C-6), 198.6 (C-2). Anal. Calcd
for C15H18OSe: C, 61.43; H, 6.19. Found: C, 61.71; H,
6.26. (3E,5E)-isomer: 77Se d (ppm) 403.7; 1H NMR
d (ppm) 0.96 (t, 3H, J¼7.4 Hz, H-9), 1.48 (m, 2H, H-8),
2.25 (s, 3H, H-1), 2.42 (m, 2H, H-7), 6.56 (d, 1H,
J¼15.1 Hz, H-3), 6.62 (t, 1H, J¼7.2 Hz, H-6), 7.10–7.35
(m, 5H, Ph), 7.54 (d, 1H, J¼15.1 Hz, H-4).
3.1.6.2. 4-Phenylselanyloct-2,4-dienenitrile 7b. Yield
82%. (2E,4Z)-isomer: 77Se d (ppm) 260.7; 1H NMR
d (ppm) 0.95 (t, 3H, J¼7.0 Hz, H-8), 1.50 (m, 2H, H-7),
2.54 (q, 2H, J¼7.0 Hz, H-6), 5.83 (d, 1H, J¼15.6 Hz, H-
2), 6.62 (t, 1H, J¼7.4 Hz, H-5), 7.10 (d, 1H, J¼15.6 Hz,
H-3), 7.12–7.40 (m, 5H); 13C NMR d (ppm) 13.9, 21.9,
35.2, 99.8 (C-2), 118.2 (C-1), 126.3, 126.7, 128.8 (C-4),
129.2, 129.7, 152.0 (C-3), 153.7 (C-5). Anal. Calcd for
C14H15NSe: C, 60.87; H, 5.47; N, 5.07. Found: C, 60.63;
1
3.1.5.3. 6-Phenyl-5-phenylselanylhexa-3,5-dien-2-one
6c. Yield 88%. (3E,5E)-isomer (cyclohexane/dichloro-
methane:85/15): 77Se d (ppm) 423.2; 1H NMR d (ppm)
2.21 (s, 3H), 6.70 (d, 1H, J¼15.4 Hz, H-3), 7.15–7.50 (m,
11H), 7.61 (dd, 1H, J¼0.9, 15.4 Hz, H-4); 13C NMR
d (ppm) 27.0 (C-1), 127.7 (C-3), 128.0, 128.2, 128.8,
129.4, 130.4, 131.1, 132.6, 134.4, 136.4 (C-5), 139.5 (C-
6), 144.8 (C-4), 198.4 (C-2). (3E,5Z)-isomer (cyclohexane/
dichloromethane: 75/25): mp 45 ꢀC, 77Se d (ppm) 308.5;
1H NMR d (ppm) 2.23 (s, 3H), 6.64 (d, 1H, J¼15.4 Hz,
H-3), 7.10–7.30 (m, 9H), 7.55 (s, 1H, H-6), 7.67–7.71 (m,
H, 5.28; N, 4.78. (2E,4E)-isomer: 77Se d (ppm) 387.1; H
NMR d (ppm) 0.98 (t, 3H, J¼7.0 Hz, H-8), 1.52 (m, 2H,
H-7), 2.52 (q, 2H, J¼7.0 Hz, H-6), 5.90 (d, 1H,
J¼15.6 Hz, H-2), 6.69 (t, 1H, J¼7.1 Hz, H-5), 7.12–7.50
(m, 6H); 13C NMR d (ppm) 12.7, 22.3, 32.0, 102.4 (C-2),
116.6 (C-1), 125.6, 127.0, 128.8 (C-4), 129.2, 129.7, 144.7
(C-5), 153.8 (C-3). (2Z,4Z)-isomer: 77Se d (ppm) 357.3;
1H NMR d (ppm) 0.97 (t, 3H, J¼7.0 Hz, H-8), 1.50 (m,
2H, H-7), 2.39 (q, 2H, J¼7.0 Hz, H-6), 5.09 (d, 1H,
J¼11.5 Hz, H-2), 6.65–6.73 (m, 2H, H-3, H-5), 7.12–7.40
(m, 5H); 13C NMR d (ppm) 13.7, 22.0, 34.3, 96.9 (C-2),

3714
S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
116.6 (C-1), 125.6, 127.2, 128.8 (C-4), 129.2, 129.7, 145.1
(C-5), 151.1 (C-3).
1.48 (m, 2H), 2.51 (q, 2H, J¼7.0 Hz), 4.17 (q, 2H,
J¼7.1 Hz), 6.28 (d, 1H, J¼15.1 Hz, H-2), 6.63 (t, 1H,
J¼7.1 Hz, H-5), 7.12–7.30 (m, 5H), 7.40 (d, 1H, J¼15.1 Hz,
H-3); 13C NMR d (ppm) 14.0, 14.4, 22.2, 35.2, 60.5, 121.8
(C-2), 126.3, 129.4, 129.8, 130.8, 131.0 (C-4), 150.0 (C-
3), 152.9 (C-5), 167.4 (C-1). (2E,4E)-isomer: 77Se d (ppm)
3.1.6.3. 5-Phenyl-4-phenylselanylpent-2,4-dienenitrile
7c. Yield 83%. (2E,4Z)-isomer (cyclohexane/dichloro-
1
methane: 80/20): mp 92 ꢀC, 77Se d (ppm) 288.2; H NMR
1
d (ppm) 5.94 (d, 1H, J¼15.6 Hz, H-2), 7.15–7.35 (m, 9H),
7.47 (s, 1H, H-5), 7.68–7.72 (m, 2H); 13C NMR d (ppm)
101.3 (C-2), 118.4 (C-1), 126.9, 127.1, 128.4, 129.7,
130.0, 130.2, 130.6, 135.3 (C-4), 147.6 (C-5), 153.0 (C-3).
Anal. Calcd for C17H13NSe: C, 65.81; H, 4.22; N, 4.51.
Found: C, 65.87; H, 3.98; N, 4.38. (2E,4E)-isomer (cyclo-
hexane/dichloromethane: 90/10): 77Se d (ppm) 408.6;
1H NMR d (ppm) 5.99 (d, 1H, J¼15.8 Hz, H-2), 7.17–
7.50 (m, 11H), 7.55 (s, 1H, H-5); 13C NMR d (ppm)
103.6 (C-2), 117.0 (C-1), 127.6, 128.3, 128.9, 129.4,
129.6, 129.8, 130.0, 131.6, 135.4 (C-4), 146.2 (C-5), 152.8
(C-3).
401.1; H NMR d (ppm) 0.96 (t, 3H, J¼7.0 Hz), 1.27 (t,
3H, J¼7.1 Hz), 1.51 (m, 2H), 2.42 (q, 2H, J¼7.0 Hz), 4.17
(q, 2H, J¼7.1 Hz), 6.33 (d, 1H, J¼15.1 Hz, H-2), 6.59 (t,
1H, J¼7.1 Hz, H-5), 7.12–7.30 (m, 5H), 7.70 (d, 1H,
J¼15.1 Hz, H-3); 13C NMR d (ppm) 13.8, 14.4, 22.5, 32.1,
60.6, 124.0 (C-2), 126.7, 129.0, 129.3, 129.8, 131.1 (C-4),
139.3 (C-3), 152.0 (C-5), 167.4 (C-1).
3.1.7.3. Ethyl 5-Phenyl-4-phenylselanylpent-2,4-dien-
oate 8c.8 Yield 84%. (2E,4Z)-isomer: 54%, mp¼55 ꢀC;
77Se d (ppm) 301.1; 1H NMR d (ppm) 1.28 (t, 3H,
J¼7.2 Hz), 4.16 (q, 2H, J¼7.2 Hz), 6.38 (d, 1H,
J¼15.1 Hz, H-2), 7.16–7.40 (m, 8H), 7.52 (s, 1H, H-5),
7.55 (d, 1H, J¼15.1 Hz, H-3), 7.67–7.73 (m, 2H); 13C
NMR d (ppm) 14.4, 60.6, 123.1 (C-2), 126.6, 127.5 (C-4),
128.3, 129.3, 129.4, 130.1, 130.4, 130.7, 136.0, 146.7
(C-3), 147.8 (C-5), 167.1 (C-1). (2E,4E)-isomer: 77Se
(2Z,4Z)-isomer (cyclohexane/dichloromethane: 85/15): 77Se
d (ppm) 398.4; 1H NMR d (ppm) 5.14 (d, 1H, J¼11.3 Hz, H-
2), 6.75 (dd, 1H, J¼1.0, 11.3 Hz, H-3), 7.15–7.35 (m, 9H),
7.55–7.60 (m, 2H); 13C NMR d (ppm) 97.7 (C-2), 116.6
(C-1), 126.6, 128.2, 128.6, 128.9, 129.1, 129.1, 129.3,
133.7, 135.8 (C-4), 138.6 (C-5), 151.8 (C-3).
1
d (ppm) 421.6; H NMR d (ppm) 1.25 (t, 3H, J¼7.1 Hz),
4.17 (q, 2H, J¼7.1 Hz), 6.46 (d, 1H, J¼15.1 Hz, H-2),
7.20–7.42 (m, 9H), 7.45–7.55 (m, 2H), 7.80 (d, 1H,
J¼15.1 Hz, H-3); 13C NMR d (ppm) 14.3, 60.6, 125.2
(C-2), 127.4, 128.2, 128.7, 129.3 (C-4), 129.5, 129.6,
130.1, 132.4, 136.2, 140.9 (C-3), 144.4 (C-5), 167.1 (C-1).
(2Z,4E)-isomer (cyclohexane/dichloromethane: 85/15):
1
77Se d (ppm); H NMR d (ppm) 5.26 (d, 1H, J¼11.8 Hz,
H-2), 6.99 (dd, 1H, J¼1.3, 11.8 Hz, H-3), 7.15–7.35 (m,
9H), 7.55–7.60 (m, 2H); 13C NMR d (ppm) 101.1 (C-2),
116.1 (C-1), 126.6, 128.2, 128.6, 128.9, 129.1, 129.1,
129.3, 133.7, 136.0 (C-4), 142.4 (C-5), 146.9 (C-3).
3.1.8. Preparation of selenoxides 9c–11c. A solution of
the diene (1 mmol) in dichloromethane (5 ml) was treated
dropwise with H2O2 (35% aqueous solution, 0.85 ml). The
reaction was stirred at room temperature for 1 h. The solu-
tion was washed with water, dried, and concentrated under
vacuum. The oily product was washed twice with light petro-
leum and the crude mixture was used directly in the next
step.
3.1.7. Preparation of dienic esters 8. A solution of n-BuLi
in hexanes (1.6 M, 3.45 ml, 5.5 mmol) was slowly added,
under argon, to triethylphosphonoacetate (1.2 g, 5.5 mmol)
in anhydrous THF (50 ml) at 0 ꢀC. After stirring for 0.5 h
at room temperature, a-phenylselanyl enal 2 (5 mmol) in
THF (5 ml) was added dropwise. The mixture was stirred
for 3 h at room temperature, quenched with saturated aque-
ous NH4Cl, and extracted with diethylether. The organic ex-
tracts were dried over magnesium sulfate and concentrated
under vacuum. The residue was purified by chromatography
on silica gel (light petroleum/CH2Cl2: 80/20).
3.1.8.1. 6-Phenyl-5-phenylseleninylhex-3,5-dien-2-one
9c. Yield 81%. Major isomer: 60%; 1H NMR (CDCl3,
200 MHz) d (ppm) 2.28 (s, 3H), 6.53 (d, 1H, J¼16.5 Hz),
7.88 (s, 1H), 7.15–7.80 (m, 11H). IR (neat): 3057, 2982,
2936, 1715, 1625, 1476, 1438, 1369, 1302, 1263, 1180,
1
1156, 1022, 737, 690 cmꢂ1. Minor isomer: 40%; H NMR
3.1.7.1. Ethyl 4-phenylselanylhex-2,4-dienoate 8a.8
(CDCl3, 200 MHz) d (ppm) 2.24 (s, 3H), 6.67 (d, 1H,
J¼16.2 Hz), 7.15–7.65 (m, 12H).
1
Yield 72%. (2E,4Z)-isomer: 77Se d (ppm) 263.6; H NMR
d (ppm) 1.27 (t, 3H, J¼7.1 Hz), 2.09 (d, 3H, J¼6.9 Hz),
4.17 (q, 2H, J¼7.1 Hz), 6.30 (dd, 1H, J¼0.6, 15.1 Hz, H-
2), 6.71 (q, 1H, J¼6.9 Hz, H-5), 7.12–7.32 (m, 5H), 7.41
(d, 1H, J¼15.1 Hz, H-3); 13C NMR d (ppm) 14.4, 19.2,
60.5, 121.6 (C-2), 126.3, 129.4, 129.8, 130.4 (C-4), 134.3,
146.9 (C-3), 147.5 (C-5), 167.4 (C-1). (2E,4E)-isomer:
77Se d (ppm) 399.6; 1H NMR d (ppm) 1.26 (t, 3H,
J¼7.1 Hz), 2.04 (d, 3H, J¼7.4 Hz), 4.17 (q, 2H, J¼7.1 Hz),
6.33 (d, 1H, J¼14.8 Hz, H-2), 6.65 (q, 1H, J¼7.1 Hz, H-5),
7.12–7.30 (m, 5H), 7.72 (d, 1H, J¼14.8 Hz, H-3); 13C NMR
d (ppm) 13.9, 19.3, 60.4, 122.3 (C-2), 126.8, 129.3, 129.8,
130.4 (C-4), 134.4, 138.9 (C-3), 147.4 (C-5), 167.3 (C-1).
3.1.8.2. 5-Phenyl-4-phenylseleninylpent-2,4-dieneni-
trile 10c. Yield 89%. Major isomer: 50%; 1H NMR
(CDCl3, 200 MHz) d (ppm) 6.22 (d, 1H, J¼16.3 Hz),
7.10–7.72 (m, 12H). Minor isomer: 25%; 1H NMR
d (ppm) 5.45 (d, 1H, J¼11.9 Hz), 6.81–8.05 (m, 12H).
Minor isomer: 25%; 1H NMR d (ppm) 5.92 (d, 1H,
J¼16.6 Hz), 6.81–7.72 (m, 12H).
3.1.8.3. Ethyl 5-phenyl-4-phenylseleninylpent-2,4-
dienoate 11c. Yield 76%. Major isomer 2E,4Z: 72%; H
1
NMR (CDCl3) d (ppm) 1.25 (t, 3H, J¼7.1 Hz), 4.16 (m,
2H), 6.51 (d, 1H, J¼15.7 Hz), 7.40–7.52 (m, 9H), 7.60 (d,
1H, J¼15.7 Hz), 7.62–7.65 (m, 2H); 13C NMR d (ppm)
14.1, 60.5, 123.0, 126.3, 128.9, 129.4, 129.7, 129.9, 131.2,
133.6, 137.0, 140.0, 140.6, 141.1, 165.7. IR (neat): 3059,
3.1.7.2. Ethyl 4-phenylselanyloct-2,4-dienoate 8b.8
1
Yield 71%. (2E,4Z)-isomer: 77Se d (ppm) 271.5; H NMR
d (ppm) 0.92 (t, 3H, J¼7.0 Hz), 1.26 (t, 3H, J¼7.1 Hz),

S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
3715
1
2981, 2935, 1954, 1887, 1714, 1621, 1576, 1476, 1439,
1368, 1303, 1266, 1176, 1134, 1100, 1022, 738, 690 cmꢂ1
3.1.9.6. Octa-3,4-dien-2-ol 13b. Yield 63%, 64/36. H
NMR d (ppm) 0.92 (t, 3H, J¼7.2 Hz), 1.28 (d, 3H,
J¼6.3 Hz), 1.43 (m, 2H), 1.70 (s, 1H), 1.99 (m, 2H), 4.32
(m, 1H), 5.23–5.31 (m, 2H); 13C NMR d (ppm) 13.8 (C-8),
22.4 (C-1), 23.6, 30.9, (66.09, 66.29, C-2),32 (94.31,
94.48), (97.0, 2C), (201.80, 201.94).32 Anal. Calcd for
C8H14O: C, 76.14; H, 11.12. Found: C, 75.92; H, 11.10.
.
1
Minor isomer 2E,4E: 28%; H NMR d (ppm) 1.30 (t, 3H,
J¼7.1 Hz), 4.22 (m, 2H), 6.25 (d, 1H, J¼16.2 Hz), 7.40–
7.55 (m, 9H), 7.70–7.82 (m, 3H); 13C NMR d (ppm) 14.1,
60.9, 122.6, 126.6, 128.8, 129.7, 129.9, 130.0, 131.7,
133.7, 136.9, 137.3, 141.3, 165.5.
3.1.9. Preparation of a-hydroxyallenes. A solution of
selenoxyde (0.9 mmol) and triethylamine (0.2 g, 2 mmol) in
THF (15 ml) was stirred at room temperature for 12 h. After
addition of water and extraction with ether, the organic layer
was dried over MgSO4 and evaporated. The allene was
purified by chromatography on silica gel (light petroleum/
ethyl acetate: 95/5).
3.1.9.7. 1-Phenyl penta-2,3-dien-1-ol 14a. Yield 38%.
Major isomer: 75%; 1H NMR d (ppm) 1.70 (dd, 3H,
J¼3.4, 6.6 Hz), 2.11 (d, 1H, J¼4.1 Hz), 5.24 (m, 1H), 5.37
(m, 2H), 7.25–7.45 (m, 5H); 13C NMR d (ppm) 14.4,
72.36 (C-1), 89.81 (C-4), 95.66 (C-2), 126.2, 127.8, 128.6,
143.2, 203.13 (C-3). IR (neat): 3390, 3025, 2924, 1969,
1451, 1234, 1196, 1044, 1014, 872, 699 cmꢂ1. Minor iso-
mer: 25%; 1H NMR d (ppm) 1.73 (dd, 3H, J¼3.4, 6.6 Hz),
2.11 (d, 1H, J¼4.1 Hz), 5.24 (m, 1H), 5.37 (m, 2H), 7.25–
7.45 (m, 5H); 13C NMR d (ppm) 14.5, 72.30 (C-1), 89.93
(C-4), 95.66 (C-2), 126.20, 127.80, 128.6, 143.2, 203.13
(C-3).
3.1.9.1. 4-Phenylbuta-2,3-dien-1-ol 12c.25 Yield 78%.
1H NMR (CDCl3, 300 MHz) d (ppm) 1.72 (br s, 1H, OH),
4.26 (m, 2H, H-1), 5.78 (q, 1H, J¼6.1 Hz, H-2), 6.32 (dt,
1H, J¼3.0, 6.1 Hz, H-4), 7.19–7.36 (m, 5H, Ph); 13C NMR
d (ppm) 60.5 (C-1), 96.0, 97.3, 127.0, 127.4, 128.8, 133.9,
137.3, 204.4 (C-3).
3.1.9.8. 1-Phenyl hepta-2,3-dien-1-ol 14b. Yield 67%,
1
75/25. H NMR d (ppm) 0.92 (t, 3H, J¼7.3 Hz, major),
3.1.9.2. 5-Phenyl penta-3,4-dien-2-ol 13c. Yield 81%,
63/37. 1H NMR d (ppm) 1.37 (d, 3H, J¼6.4 Hz), 1.86
(br s, 1H), 4.47 (m, 1H, H-2), 5.72 (m, 1H, H-3), 6.30
(dd, 1H, J¼2.3, 6.4 Hz, H-5), 7.18–7.34 (m, 5H);
13C NMR d (ppm) (22.48, 22.62, C-1), (64.88, 65.19,
C-2), (96.19, 96.37, C-5),32 99.87 (2C), 125.8, 126.2,
127.4, (132.93, 133.0),32 (202.21, 202.26, C-4).32 Anal.
Calcd for C11H12O: C, 82.46; H, 7.55. Found: C, 82.80;
H, 7.72.
0.94 (t, 3H, J¼7.3 Hz), 1.44 (m, 2H), 2.01 (m, 1H), 2.13
(d, 1H, J¼4.0 Hz, OH), 5.24 (m, 1H), 5.39 (m, 2H), 7.25–
7.42 (m, 5H); 13C NMR d (ppm) 13.8, 22.4, 30.9, 72.4,
(72.32, 72.5, C-1),32 (94.99, 94.85, C-4),32 (96.17, 2C),
126.2, 126.3, 127.8, 128.6, 143.3, (202.35, 202.45, C-3).32
IR (neat): 3386, 2960, 2931, 2872, 1963, 1454, 1233,
1217, 1022, 879, 757, 699. Anal. Calcd for C13H16O: C,
82.93; H, 8.57. Found: C, 82.61; H, 8.34.
3.1.9.9. Ethyl-2-hydroxyhexa-3,4-dienoate 15a.8 Yield
30%, 100/0. 1H NMR d (ppm) 1.30 (t, 3H, J¼7.2 Hz),
1.70 (dd, 3H, J¼3.1, 7.0 Hz), 2.89 (d, 1H, J¼6.9 Hz, OH),
4.25 (m, 2H), 4.62 (ddd, 1H, J¼2.7, 6.0, 6.9 Hz, H-2),
5.25 (ddq, 1H, J¼3.1, 6.0, 7.0 Hz, H-3), 5.35 (ddq, 1H,
J¼2.7, 7.0, 7.2 Hz, H-5); 13C NMR d (ppm) 14.1, 14.3,
62.0, 69.0 (C-2), 90.4 (C-3), 90.7 (C-5), 173.4 (C-1), 204.4
(C-4). IR (neat): 3473, 2982, 2928, 2855, 1969, 1736,
3.1.9.3. 1,4-Diphenyl buta-2,3-dien-1-ol 14c.8 Yield
81%, 70/30. 1H NMR d (ppm) 2.16 (d, 1H, J¼4.1 Hz,
OH), 5.41 (ddd, 1H, J¼2.2, 4.1, 6.5 Hz, H-1), 5.88 (dd,
1H, J¼6.3, 6.5 Hz, H-2), 6.39 (dd, 1H, J¼2.2, 6.3 Hz,
H-4), 7.20–7.50 (m, 10H); 13C NMR d (ppm) (72.29,
72.49, C-1), (97.72, 98.03),32 (99.98, 2C), 126.1, 127.0,
127.5, 128.0, 128.7, 128.8, 133.8, 143.0, (203.9, C-3).
1445, 1369, 1302, 1262, 1200, 1095, 1023, 868 cmꢂ1
.
3.1.9.4. Ethyl 2-hydroxy-5-phenylpenta-3,4-dienoate
15c.8 Yield 75%. Major isomer: 70%; H NMR d (ppm)
1
3.1.9.10. Ethyl 2-hydroxyocta-3,4-dienoate 15b.8 Yield
30%, 72/28. 1H NMR d (ppm) 0.93 (t, 3H, J¼7.3 Hz), 1.31
(t, 3H, J¼6.9 Hz), 1.44 (m, 2H), 2.01 (m, 2H), 2.83 (major
diast. d, 1H, J¼7.4 Hz, OH), 2.84 (minor diast. d, 1H,
J¼7.3 Hz, OH), 4.26 (m, 2H), 4.61 (ddd, 1H, J¼2.7, 6.0,
7.4 Hz, H-2), 5.30 (ddt, 1H, J¼3.1, 6.0, 7.1 Hz, H-3), 5.41
(ddt, 1H, J¼2.7, 6.4, 7.1 Hz, H-5); 13C NMR d (ppm)
13.7, 14.3, (22.19, 22.26),32 (30.53, 30.57),32 62.0, (69.11,
69.28, C-2),32 (91.18, 91.23, C-3),32 (95.52, 95.61, C-5),32
173.4 (C-1), 203.6 (C-4). IR (neat): 3473, 2961, 2933,
2874, 1966, 1732, 1464, 1370, 1260, 1197, 1095, 1023,
1.25 (t, 3H, J¼7.2 Hz), 2.97 (d, 1H, J¼7.6 Hz, OH), 4.25
(m, 2H), 4.77 (ddd, 1H, J¼2.8, 6.1, 7.6 Hz, H-2), 5.78 (t,
1H, J¼6.1 Hz, H-3), 6.41 (dd, 1H, J¼2.8, 6.1 Hz, H-5),
7.20–7.33 (m, 5H); 13C NMR d (ppm) 14.2, 62.4, 69.0
(C-2), 95.1 (C-3), 98.6 (C-5), 127.1, 127.6, 128.7, 133.1,
173.2 (C-1), 205.1 (C-4). IR (neat): 3457, 2983, 2937,
1954, 1732, 1454, 1371, 1205, 1095, 1023, 699 cmꢂ1. Minor
1
isomer, H NMR d (ppm) 1.32 (t, 3H, J¼7.2 Hz), 3.03
(d, 1H, J¼6.9 Hz, OH), 4.24 (q, 2H, J¼7.1 Hz), 4.77
(ddd, 1H, J¼2.6, 6.4, 6.9 Hz, H-2), 5.72 (t, 1H, J¼6.4 Hz,
H-3), 6.40 (dd, 1H, J¼2.6, 6.4 Hz, H-5), 7.20–7.33
(m, 5H); 13C NMR d (ppm) 14.2, 62.3, 69.2 (C-2), 95.2
(C-3), 98.4 (C-5), 127.1, 127.7, 128.7, 133.3, 173.1 (C-1),
205.4 (C-4).
861 cmꢂ1
.
3.1.9.11. Ethyl-2-hydroxy-5-phenylpenta-3,4-dienoate
1
15c.8 Yield 75%, 60/40. H NMR d (ppm) Major isomer:
1.25 (t, 3H, J¼7.2 Hz), 2.97 (d, 1H, J¼7.6 Hz, OH), 4.25
(m, 2H), 4.77 (ddd, 1H, J¼2.8, 6.1, 7.6 Hz, H-2), 5.78 (t,
1H, J¼6.1 Hz, H-3), 6.40 (dd, 1H, J¼2.8, 6.1 Hz, H-5),
7.17–7.35 (m, 5H); 13C NMR d (ppm) 14.2, 62.3, 69.0
(C-2), 95.2 (C-3), 98.7 (C-5), 127.1, 127.7, 128.8, 133.1,
173.12 (C-1), 205.07 (C-4). Minor isomer: 1.32 (t, 3H,
1
3.1.9.5. Hexa-3,4-dien-2-ol 13a. Yield 51%, 60/40. H
NMR d (ppm) 1.28 (d, 3H, J¼6.3 Hz), 1.69 (dd, 3H,
J¼1.2, 6.9 Hz), 4.32 (m, 1H), 5.21–5.29 (m, 2H); 13C
NMR d (ppm) (14.2, 2C), (23.3, 2C), (66.0, 2C), 88.9,
(96.3, 2C), 996.3, 202.4.

3716
S. Redon et al. / Tetrahedron 63 (2007) 3707–3717
J¼7.2 Hz), 3.03 (d, 1H, J¼6.9 Hz, OH), 4.25 (m, 2H), 4.77
(ddd, 1H, J¼2.6, 6.4, 6.9 Hz, H-2), 5.72 (t, 1H, J¼6.4 Hz,
H-3), 6.40 (dd, 1H, J¼2.6, 6.4 Hz, H-5), 7.17–7.35 (m,
5H); 13C NMR d (ppm) 14.2, 62.2, 69.0 (C-2), 95.2 (C-3),
98.6 (C-5), 127.1, 127.7, 128.8, 133.1, 173.15 (C-1),
205.43 (C-4). IR (neat): 3457, 2983, 2937, 1954, 1732,
under reflux and then concentrated under vacuum. The
a-halogenoallene was chromatographed on silica gel (light
petroleum/CH2Cl2: 95/5).
3.1.11.1. 4-Chloro-1-phenylbuta-1,2-diene 20c.21 Yield
58%. 1H NMR d (ppm) 4.15 (2H, dd, J¼7.5, 2.0 Hz),
5.80 (1H, m), 6.34 (1H, dt, J¼2.0, 6.3 Hz), 7.23–7.34 (5H,
m); 13C NMR d (ppm) 42.4, 93.5, 97.1, 127.2, 127.7,
128.8, 133.5, 206.5.
1454, 1371, 1205, 1095, 1025, 862, 770, 699 cmꢂ1
.
3.1.10. Preparation of tert-butyl-N-allenyl carbamates.
To a solution of selenide (1 mmol), tert-butyl carbamate
(0.35 g, 3 mmol), triethylamine (0.8 g, 8 mmol) in methanol
(3 ml) and N-bromosuccinimide (0.35 g, 3 mmol) were
slowly added at 0 ꢀC. The mixture was stirred for 45 min,
diluted with ethyl acetate (10 ml), and treated with an
aqueous saturated solution of NaCl (10 ml). After extraction
and concentration, the oily residue was chromatographed on
silica gel (light petroleum/ethyl acetate: 95/5).
3.1.11.2. 4-Chloro-1-phenylpenta-1,2-diene 21c. Yield
1
87%. H NMR d (ppm) 1.68 (3H, d, J¼6.5 Hz), 4.69 (1H,
m, H-4), 5.87 (1H, t, J¼6.5 Hz, H-3), 6.39 (1H, dd, J¼2.1,
6.5 Hz, H-1), 7.20–7.35 (5H, m); 13C NMR d (ppm) 25.1
(C-5), 55.1 (C-4), 98.1, 100.0, 127.1, 127.7, 128.9, 133.5,
204.4 (C-2). Anal. Calcd for C11H11Cl: C, 73.94; H, 6.21.
Found: C, 74.12; H, 6.13.
3.1.10.1. tert-Butyl-N-(4-phenylbut-2,3-dien-1-yl)car-
bamate 16c. Yield 53%. H NMR d (ppm) 1.33 (9H, s),
3.1.11.3. 4-Bromo-1-phenylpenta-1,2-diene 22c. Yield
1
1
61%. H NMR d (ppm) 1.72 (3H, d, J¼6.7 Hz), 5.25 (1H,
3.77 (2H, m), 4.66 (1H, br s), 5.57 (1H, q, J¼5.6 Hz), 6.21
(1H, dt, J¼3.2, 5.6 Hz), 7.10–7.26 (5H, m); 13C NMR
d (ppm) 28.5, 39.2, 79.7, 93.6, 97.5, 127.0, 127.3, 128.8,
134.0, 155.8, 204.5. Anal. Calcd for C15H19NO2: C, 72.18;
H, 7.02; N, 6.11. Found: C, 72.44; H, 7.31; N, 5.81.
m), 5.52 (1H, t, J¼6.6 Hz), 7.16 (1H, dd, J¼1.7, 6.6 Hz),
7.14–7.32 (5H, m); 13C NMR d (ppm) 26.4, 68.2, 100.1,
102.6, 128.6, 129.2, 131.5, 135.9, 208.2. Anal. Calcd for
C11H11Br: C, 59.22; H, 4.97. Found: C, 59.12; H, 5.21.
3.1.10.2.
tert-Butyl-N-(5-phenylpent-3,4-dien-2-yl)-
Acknowledgements
carbamate 17c. Yield 48%. 1H NMR d (ppm) 1.30 (3H, d,
J¼6.7 Hz), 1.40 (9H, s), 4.32 (1H, m), 4.52 (1H, br s),
5.65 (1H, t, J¼5.3 Hz), 6.24 (1H, dd, J¼3.1, 5.3 Hz),
7.13–7.24 (5H, m); 13C NMR d (ppm) 21.8, (27.03,
27.48),32 39.2, 52.55, 96.9, 98.1, 125.8, 127.2, 128.9,
133.0, 152.0, 202.5. Anal. Calcd for C16H21NO2: C, 74.10;
H, 8.16; N, 5.40. Found: C, 74.07; H, 8.32; N, 5.53.
We thank the region Haute-Normandie (doctoral fellowship
to S.R.) for financial support of this research.
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1
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