A novel 3,4-bis(sulfenyl)- or 4-selenenyl-3-sulfenylpenta-2,4-dienylation of aldehydes using 4-ethoxy-1,2-bis(sulfenyl)- or 1-selenenyl-2-sulfenylbuta-1, 3-dienyl lithiums

Article abstract of DOI:10.1248/cpb.51.1405

3,4-Dichalcogenopenta-2,4-dienylation of aldehydes proceeded in good to high yields using 4-ethoxy-1-(benzenesulfenyl)-2-(methanesulfenyl)- (5), 4-ethoxy-1,2-bis(benzenesulfenyl)but-1,3-diene (6), and 1-selenenyl derivatives 7 and 8. This novel four-carbo

Full text of DOI:10.1248/cpb.51.1405

December 2003
Chem. Pharm. Bull. 51(12) 1405—1412 (2003)
1405
A Novel 3,4-Bis(sulfenyl)- or 4-Selenenyl-3-sulfenylpenta-2,4-dienylation of
Aldehydes Using 4-Ethoxy-1,2-bis(sulfenyl)- or 1-Selenenyl-2-sulfenyl-
buta-1,3-dienyl Lithiums
Mitsuhiro YOSHIMATSU,* Yasutaka MATSUURA, and Kohei GOTOH
Department of Chemistry, Faculty of Education, Gifu University; Gifu 501–1193, Japan.
Received September 9, 2003; accepted September 26, 2003; published online September 29, 2003
3,4-Dichalcogenopenta-2,4-dienylation of aldehydes proceeded in good to high yields using 4-ethoxy-1-(ben-
zenesulfenyl)-2-(methanesulfenyl)- (5), 4-ethoxy-1,2-bis(benzenesulfenyl)but-1,3-diene (6), and 1-selenenyl deriv-
atives 7 and 8. This novel four-carbon homologation could be applied to a synthesis of 3,4,7,8-tetrakis(benzene-
sulfenyl)-10,10-dimethylundeca-2,4,6,8-tetraenal (20).
Key words 4-ethoxy-1,3-butadienyl lithium; penta-2,4-dienal; sulfur; selenium
Four-carbon homologation is one of the important and the NOE experiments as 4E,6E. The reaction of the di-
processes in the syntheses of the polyene antibiotics and enyl lithium with aldehydes was found to stereoselectively
pheromones and other bioactive compounds.1—3) The most occur by the stabilizing effect of b-heteroatom substituents
useful reagents are the triethyl phosphonoesters (Horner– of the alkenyl lithiums.16,17) The large excess of n-BuLi pro-
Wadsworth–Emmons reagents) or the Wittig type reagents, vided the deethoxylated penta-2,4-dienyl alcohol 10 (Entry
which directly react with the aldehydes and ketones to give 7).
the penta-2,4-dienals.4—7) 4-Alkoxybuta-1,3-dienyl lithiums
as the other useful reagents have been reported by Wollen-
berg or Duhamel to easily utilize the four-carbon homologa-
tion using 4-alkoxybuta-1,3-dienyl tributyltin,8—10) chloride
and bromides;11) however, more functionalized 4-alkoxybuta-
1,3-dienyl lithiums have been hitherto unknown.12) Recently,
we reported the two-carbon homologations such as the a-
sulfenyl13,14) or a-selenenyl15) formylation of aldehydes and
ketones using b-alkoxyalkenyl lithiums. Next our attention
has been focused on the four-carbon homologation of the
carbonyl compounds. If a new 4-alkoxybuta-1,3-dienyl lithi-
ums bearing an a- and b-sulfenyl or selenenyl functional
groups would be generated, they will easily react with car-
bonyl compounds and the following hydrolysis to succeed a
new type of four-carbon homologation of the carbonyl com-
pounds. Now we here report a novel four-carbon homologa-
tion of aldehydes using 4-ethoxybuta-1,3-dienyl lithiums sta-
Reagents: i, EtMgBr/CH(OEt)3/reflux; ii, NaOEt/EtOH/rt then MeSNa/reflux/2 h or
PhSH/reflux/2 h; iii, t-BuOK/t-BuOH/1 h.
bilized by the 1- and 2-chalcogene groups and its application
to the synthesis of 2,4,6,8-nonatetraenal.
Chart 1
First, we show the preparations of the dienes 5—8 in Chart
1. Phenyl propargyl sulfide 1a was treated with EtMgBr/
CH(OEt)3 to give the acetal 2a, which easily isomerized to
the allenyl sulfide 3 with NaOEt, the successive addition of
thiophenol or 15% NaSMe in water to give (E)- and (Z)-but-
3-enal acetals 4a and (E)- and (Z)-4b. Treatment of (E)- and
(Z)-3,4-bis(sulfenyl)but-3-enal acetals with t-BuOK pro-
vided the titled 4-ethoxy-1,2-bis(sulfenyl)dienes 5 and 6 in
good yields. The methanesulfenyl diene 5 is so labile at room
temperature that it must be immediately used at the next step.
Selenium derivatives 7 and 8 were also obtained by the same
methods.
Table 1. A Lithiation and Reaction of Diene 5 with Pivalaldehyde
Entry
Condition
Products (% yield)
1
2
3
4
5
6
7
8
n-BuLi(1.5 eq)/THF/Ϫ50 °C
t-BuLi(1.5 eq)/THF/Ϫ70 °C
Recover
Recover
9a (34)
Recover
t-BuOK(3 eq)/n-BuLi(3 eq)/THF/Ϫ70 °C
TMEDA/n-BuLi(3 eq)/THF/Ϫ50 °C
DBU(3 eq)/n-BuLi(3 eq)/THF/Ϫ50 °C
DABCO(3 eq)/n-BuLi(3 eq)/THF/Ϫ50 °C
DABCO(5 eq)/n-BuLi(5 eq)/THF/Ϫ20 °C
LTMP(3 eq)/THF/Ϫ50 °C
9a (30)a)
9a (60)
9a (53)
9a (40)
5 (14)
10 (10)b)
Next, we examined the lithiation and the reaction of the 4-
ethoxybuta-1,3-diene 5 with pivalaldehyde (Table 1). We
found that 5 easily undergo lithiation with n-BuLi/DABCO
at Ϫ50 °C and react with pivalaldehyde afforded the pentadi-
enyl alcohol 9a. The structure of 9a was determined by spec-
tral and analytical data. The stereochemistry was elucidated
a) n-BuCH(OH)t-Bu was accompanied by the product 9a. b)
1
by the H-NMR coupling constants of the olefinic protons
To whom correspondence should be addressed. e-mail: yoshimae@cc.gifu-u.ac.jp
© 2003 Pharmaceutical Society of Japan

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Vol. 51, No. 12
1
we observed it by the H-NMR spectrum, exhibiting two
kinds of the other doublets due to (2E,4Z)- and (2E,4E)-11d
at 9.54 (d, Jϭ7 Hz), 9.29 (d, Jϭ7 Hz), 6.31 (d, Jϭ7 Hz), and
5.73 (d, Jϭ7 Hz). Next, we examined the lithiation and alky-
lation of 2-phenylsulfenylbuta-1,3-diene 6; however, the
method A was found to be not effective. 2-Phenyl-
sulfenylbuta-1,3-diene 6 gave the alcohols by the modified
Method B, then the successive treatment with SOCl2/pyridine
afforded the penta-2,4-dienals 14a—c (entries 4—6). The se-
lenium analogs gave satisfactory results by the Method C and
the successive reactions with SOCl2/pyridine (entries 7—10).
The alkylation of 7 and 8 by the Methods A or B gave rise to
the formation of diphenyl diselenide, which decomposed in
the reaction conditions, and the yields of the products were
low. We could not find the reasons; however, it is very impor-
tant for the selection of the base for the a-deprotonation of
the organoselenium compounds. If the formed carbanions are
not utilized immediately, phenylselenenyl anion forms by the
a-elimination.18) When the base for the a-deprotonation of
the organoselenium compounds is not suitable, the formation
of the diphenyl diselenides are also observed. Potadium di-
isopropylamine-lithium tert-butoxide (KDA) has been known
to act as a nonnucleophilic and strong base for the a-depro-
tonation of the organoselenium compounds such as the
vinylic selenides and the selenoacetals.18) The stereo-
chemistries of the 2,4-pentadienylated products showing in
Fig. 1 were determined by the NOE experiments. The NOE
analysis indicates that the d values for the formyl group and
2-H of 2E-isomers appear higher upfield than that of the 2Z-
isomers. The stereochemistries for the other products could
not be determined by the NOE experiments; however, we
would speculate the stereochemistries of the other products
as shown in Table 4 by supporting the chemical shifts values
observed in Fig. 1.
Next, we performed the conversion of the alcohol 9a to the
penta-2,4-dienals (Table 2). The desirable penta-2,4-dienal
11a was obtained by SOCl2/pyridine without producing the
intramolecularly cyclized products such as 12, which could
not characterize because of the existence of a lot of regio- or
stereoisomers. The structure of 11a was determined by the
spectral data, which shows the characteristic pair of doublets
due to the formyl proton and 2-H (Jϭ7 Hz).
The penta-2,4-dienylations of other aldehydes using 5—8
were examined and the results are shown in Table 3. The re-
actions of 5 with aromatic and aliphatic aldehydes provided
the penta-2,4-dienylated products 11b—c in moderate yields
(entries 1—2); however, the reaction with ketones such as
acetophenone or acetone did not give the alcohols. The prod-
uct of the reaction with propionaldehyde first provided
(2Z,4Z)-11d as a single stereoisomer (Entry 3); however, the
CDCl3 solution of (2Z,4Z)-11d was stirred for overnight and
Table 2. Conversion of Penta-2,4-dien-1-ol 9a to the Penta-2,4-dienal 11a
Entry
Condition
Products (% yields)
1
2
3
4
5
6
TsOH(1 eq)/THF–H2O(10 : 1)/reflux
TMSOTf(1 eq)/CH2Cl2/Ϫ78 °C
CF3SO3H(1 eq)/THF–H2O/0 °C
PPTS(1 eq)/THF–H2O/reflux
SOCl2(1 eq)/pyridine(2 eq)/CH2Cl2/Ϫ20 °C
(CH3SO2)2O(1 eq)/i-Pr2NEt(2 eq)/
CH2Cl2/Ϫ78 °C
11a (38)
a complex mixture
11a (32)a)
Recover
11a (55)
a complex mixture
7
Polyphosphoric acid trimethylsilyl ester/
ClCH2CH2Cl/0 °C
a complex mixture
a) Some cyclizations occurred and one type of the cyclized product 12 was shown as
follows; however, they were not characterized because the products were obtained as
mixtures of the stereoisomers.
We further investigated the penta-2,4-dienylation of alde-
hyde 14a in order to clarify the scope and limitation of this
methodology. 6,6-Dimethyl-3,4-bis(phenylsulfenyl)hepta-
2,4-dienal 14a reacted with the lithiated diene 6 to stereose-
lectively afford the alcohol 19 in 49% yield (Chart 2). Reac-
Table 3. b,g-Bis(chalcogeno)penta-2,4-dienylation of Aldehydes
Diene 5—8
Aldehyde
R2
Products (% yields)
Entry
R1
Y
S
Alcohol
Methoda)
Aldehyde
1
2
3
4
5
6
7
8
9
5
5
5
6
6
6
7
7
8
8
Me
Me
Me
Ph
2,4,6-Trimethylphenyl
9b (57)
9c (50)
9d (47)
13a (56)
13b (68)
13c (63)
15a (54)
15b (68)
17a (67)
17b (76)
A
A
A
B
B
B
C
C
C
C
(2Z,4Z)-11b (37) (2Z,4E)-11b (10)
(2Z,4Z)-11c (59)
Ph
CH3CH2
(2Z,4Z)-11d (37) 2E-11d (4Z : 4Eϭ41 : 59) (15)
(2Z,4Z)-14a (70)
S
t-Bu
Ph
Ph
Ph
(2Z,4Z)-14b (67)b)
(E)-PhCHϭCH
Ph
(E)-PhCHϭCH
Ph
(2Z,4E)-14c (75)
Me
Me
Ph
Se
Se
(2Z,4E)-16a (67) (2E)-16a (4Z : 4Eϭ65 : 35) (24)
16b (4Z : 4Eϭ83 : 17) (53)
(2Z,4Z)-18a (73)c)
10
Ph
(E)-PhCHϭCH
(2Z,4Z,6E)-18b (39)d) (2E,4Z,6E)-18b (4Z : 4Eϭ72 : 28) (26)
a) Method A: DABCO(3 eq)/n-BuLi(3 eq)/Ϫ50 °C/THF (4 ml/1 mmol of 5)/10 min; method B: lithium 2,2,6,6-tetramethylpiperidide (LTMP)(3 eq)/Ϫ50 °C/THF
(3.6 ml/1 mmol of 6)/10 min; method C: t-BuOK(3 eq)/LTMP(3 eq)/Ϫ78 °C/THF (5 ml/1 mmol of 7 or 8)/10 min. b) The diethyl acetal of 14b was obtained in 17% yield. c)
The diethylacetal of 18a was obtained in 12% yield. d) The diethyl acetal of 18b was obtained in 22% yield.

December 2003
1407
Table 4. Chemical Shifts of the 2,4-Pentadienals
Chemical sifts
(ppm)
Chemical sifts
(ppm)
Compound
Compound
CHO
2-H
CHO
2-H
(2Z,4Z)-11a
(2Z,4Z)-11b
(2Z,4E)-11b
(2Z,4Z)-11c
(2Z,4Z)-11d
(2E,4Z)-11d
(2E,4E)-11d
(2Z,4Z)-14a
(2Z,4Z)-14b
(2Z,4Z,6E)-14c
9.85
9.95
9.91
9.95
9.96
9.54
9.29
10.09
10.02
10.26
6.26
6.36
5.63
6.31
6.24
6.06
5.73
6.42
6.80
7.05
(2Z,4Z)-16a
(2E,4Z)-16a
(2E,4E)-16a
(2E,4Z,6E)-16b
(2E,4E,6E)-16b
(2Z,4Z)-18a
(2Z,4Z,6E)-18b
(2E,4Z,6E)-18b
(2E,4E,6E)-18b
9.83
9.32
9.66
9.35
9.45
10.11
10.25
9.35
9.49
6.10
5.66
5.49
5.80
5.65
6.57
6.87
5.48
5.33
Reagents: i, 0.1 eq p-TsOH/CH2Cl2/rt.
Chart 3
Reagents: i, CH(OEt)3(5 eq)/EtOH/p-TsOH(0.1 eq); ii, 1-phenyl-1-trimethylsilyl-
oxyethene/BF3 Et2O/Ϫ70 °C; iii, 1-ethylthio-1-trimethylsilyloxyethylene/BF3 Et2O/
CH2Cl2/Ϫ78 °C.
Chart 4
fonic acid at room temperature. The intramolecular cycliza-
tion occurred to give a cyclopentenone 22a in 20% yield, ac-
companied by the other complex mixtures. The plausible
mechanism for this cyclization is shown in Chart 3. The
formyl group of the diene would be activated by the protic
acid. The nucleophilic double bond attacks to the carbonyl
carbon to give the allylic cation 23. It would undergo isomer-
ization to the cyclopentenone via the dienol 24. 5-Phenyl
substituted pentadienal 14b also underwent acid-promoted
cyclization to afford the cyclopentenone 22b.
Fig. 1. NOE Enhancements of the Penta-2,4-dienals
Both the pentadienyl alcohol 13a, 17a, and the penta-2,4-
dienals 14a, 18a easily converted to the corresponding ac-
etals 25 and 27, respectively. Although the sulfur and sele-
nium functional groups could stabilize the carbenium
ions,19—22) we investigated Lewis-acid promoted nucleophilic
substitution reaction of these acetals with some nucleophiles.
Reaction of 25 with the 1-phenyl-1-trimethylsilyloxyethene
gave the alkylated dienone 26 in 51% yield (Chart 4). The
reaction of 27 with 1-ethylthio-1-trimethylsilyloxyethylene
gave the thio ester 28.
Reagents: i, PhSCHϭC(SPh)CHϭCHOEt/LTMP/Ϫ50 °C; ii, SOCl2/pyridine/Ϫ20 °C;
iii, 2,4-dinitrophenylhydradine/p-toluenesulfonic acid/benzene/reflux/10 min.
We have here showed that the penta-2,4-dienylations with
aldehydes using 4-ethoxy-1,2-bis(sulfenyl)- or 1-sulfenyl-2-
selenenylbuta-1,3-dienes proceeded in moderate to good
yields. The penta-2,4-dienals and the acetals are highly reac-
tive and converted to the more useful compounds. The alde-
hyde 20, obtained by the second pentadienylation reaction,
has a unique alkatetraenal structure. Now we are studying
the photo-reactions of the 3,4,7,8-tetrakis(sulfenyl)-2,4,6,8-
alkatetraenals. These results will be reported elsewhere.
Chart 2
tion of 19 with SOCl2/pyridine gave 3,4,7,8-tetrakis(phenyl-
sulfenyl)-10,10-dimethylundeca-2,4,6,8-tetraenal 20 as a sin-
gle stereoisomer. The structure of 20 was determined by the
IR, the 1H- and the 13C-NMR, the high-resolution mass spec-
trum. The aldehyde 20 is a red oil, of which converted to the
corresponding hydrazone 21 and could be isolated as red
needles.
Experimental
These 2,3-bis(sulfenyl)penta-2,4-dienals were found to be
highly reactive. The CH2Cl2 solution of 14a was stirred for
Melting points were determined on Yanagimoto micro-melting point ap-
paratus and are uncorrected. Elemental analyses were performed at the Cen-
30 min in the presence of a catalytic amount of p-toluenesul- ter of Instrumentation of Gifu University. 1H- and 13C-NMR spectra were

1408
Vol. 51, No. 12
determined with a JEOL ECA (500 MHz) spectrometer at the Center of In- 6.90.
strumentation of Gifu University. Chemical shifts are expressed in ppm with
3Z- and 3E-4-(Benzeneselenenyl)-3-(methanesulfenyl)but-3-enal Di-
respect to tetramethylsilane as an internal standard. Splitting patterns are ethyl Acetal (4c) 62%, yellow oil, IR (film, cmϪ1) n 1120, 1060 (C–O);
designated as follows: sϭsinglet, dϭdoublet, tϭtriplet and qϭquartet. J val- 1H-NMR (500 MHz, CDCl3) d: 1.20 (t, Jϭ7 Hz, Z-Me), 1.22 (t, Jϭ7 Hz, E-
ues are given in Hz. IR spectra of solids (KBr) and liquids (film) were Mex2), 2.04 (s, Z-Me), 2.31 (s, E-SMe), 2.65 (d, Jϭ6 Hz, Z-CH2), 2.84 (d,
recorded on a JASCO IR A-100 infrared spectrometer. Electron impact mass Jϭ6 Hz, E-CH2), 3.50—3.57 (m, OCH2), 3.67—3.74 (m, OCH2), 4.70 (t,
spectra (EI-MS) were obtained using a JEOL GCmate spectrometer with a Jϭ5 Hz, E-CHO), 4.73 (t, Jϭ6 Hz, Z-CHO), 6.13 (s, E-olefinic H), 6.66 (s,
direct insertion probe at an ionization voltage of 70 eV.
Z-olefinic H), 7.20—7.29 (m, ArH), 7.42—7.45 (m, ArH); EI-MS m/z 346
Preparations of 4-Benzenesulfenyl- (2a) or 4-Benzeneselenenyl-but-2- (Mϩ). Anal. Calcd for C15H22O2SSe: C, 52.17; H, 6.42. Found: C, 52.10; H,
ynal Diethyl Acetals (2b) Thiophenol (11.0 g, 0.10 mol) was added drop- 6.37.
wise to an ether (100 ml) solution of propargyl bromide (11.9 g, 0.10 mol)
3Z- and 3E-4-(Benzeneselenenyl)-3-(benzenesulfenyl)but-3-enal Di-
and triethylamine (20.2 g, 0.20 mol) at 0 °C. The mixture was stirred for 2 h ethyl Acetal (4d) Quant., yellow oil, IR (film, cmϪ1) n 1120, 1060 (C–O);
at room temperature. The precipitates were filtered off and washed with 1H-NMR (500 MHz, CDCl3) d: 1.15 (t, Jϭ7 Hz, Z-Me), 1.21 (t, Jϭ7 Hz, E-
ether. The combined ether solution was poured into water (200 ml). The or- Me), 2.55 (d, Jϭ6 Hz, Z-olefinic H), 2.76 (d, Jϭ6 Hz, E-olefinic H), 3.48—
ganic layer was separated and the aqueous layer was extracted with ether. 3.53 (m, OCH2), 3.65—3.69 (m, OCH2), 4.67 (t, Jϭ6 Hz, Z-olefinic H), 4.74
The combined organic layer was dried over MgSO4. The solvent was re-
(t, Jϭ6 Hz, E-olefinic H), 6.83 (s, E-olefinic H), 7.23—7.44 (m, ArH); EI-
moved under reduced pressure. The residue was almost pure propargyl MS m/z 408 (Mϩ). Anal. Calcd for C20H24O2SSe: C, 58.96; H, 5.94. Found:
phenyl sulfide (1a) (quant.) and used to the next step without any purifica- C, 58.77; H, 5.89.
tion. An ether (20.0 ml) solution of phenyl propargyl sulfide (6.08 g,
Preparation of (1Z,3E)-1-Benezenesulfeny-2-ethoxy-3-(methane-
41.0 mmol) was added dropwise to an ether (100 ml) solution of ethyl mag- sulfenyl)buta-1,3-diene (5) (Typical Procedure) t-BuOK (3.76 g,
nesium bromide (prepared from EtBr (6.70 g, 61.5 mmol) and Mg (1.50 g, 33.5 mmol) was added to a solution of 3Z- and 3E-4-(benzenesulfenyl)-3-
61.5 mmol)) at room temperature. The reaction mixture was refluxed for (methanesulfenyl)but-3-enal diethyl acetal (4a) (1.0 g, 3.35 mmol) in t-
30 min. Triethyl orthoformate (36.5 g, 246 mmol) was added to the mixture. BuOH (30 ml). The reaction mixture was refluxed for 1 h and then poured
After the further reflux for 2 h, the whole was poured into water (300 ml). into water (150 ml). The organic layer was separated and the aqueous layer
The organic layer was separated and the aqueous layer was extracted with was extracted with ether. The combined organic layer was dried over
ether. The combined organic layer was dried over MgSO4. The solvent and MgSO4. The solvent was removed under reduced pressure. The residue was
triethyl orthoformate were removed under reduced pressure. The residue was purified with column chromatography on silica gel eluting with AcOEt–n-
purified by the column chromatography on silica gel eluting with AcOEt–n- hexane (1 : 100). (1Z,3E)- and (1E,3E)-1-Benezenesulfeny-4-ethoxy-2-
hexane (1 : 10) to give 4-benzenesulfenylbut-2-ynal diethyl acetal (2a) (methanesulfenyl)buta-1,3-diene (5) (0.85 g, 97%) (1Z : 1Eϭ85 : 15) was ob-
1
(6.57 g, 64%) as a yellow oil. IR (film, cmϪ1) n 2200 (acetylene); H-NMR tained as a pale yellow oil. The diene should be used immediately. IR (film,
(500 MHz, CDCl3) d: 1.18 (6H, t, Jϭ7 Hz, Meϫ2), 3.48—3.54 (2H, m,
CH2), 3.59—3.65 (2H, m, CH2), 3.67 (2H, d, Jϭ2 Hz, SCH2), 5.23 (1H, t,
cmϪ1) n 1200—900 (C–O); 1H-NMR (500 MHz, CDCl3) d: 1.30 (t, Jϭ7 Hz,
E-Me), 1.31 (t, Jϭ7 Hz, Z-Me), 2.04 (s, E-Me), 2.29 (s, Z-Me), 3.83 (q,
Jϭ2 Hz, CH), 7.23—7.29 (1H, m, ArH), 7.30—7.33 (2H, m, ArH), 7.42— Jϭ7 Hz, OCH2), 3.89 (q, Jϭ7 Hz, OCH2), 5.59 (d, Jϭ12 Hz, E-olefinic H),
7.45 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: 15.22 (qϫ2), 22.94 (t), 5.97 (s, Z-olefinic H), 6.07 (d, Jϭ12 Hz, Z-olefinic H), 6.39 (s, E-olefinic H),
60.93 (tϫ2), 78.94 (s), 81.72 (s), 91.46 (d), 127.13 (d), 129.11 (dϫ2), 6.91 (d, Jϭ12 Hz, E-olefinic H), 7.08 (d, Jϭ12 Hz, Z-olefinic H), 7.16—7.23
130.48 (dϫ2), 135.03 (s); EI-MS m/z 250 (Mϩ). Anal. Calcd for C14H18O2S: (m, ArH), 7.24—7.33 (m, ArH); 13C-NMR of Z-5 d: 14.92 (q), 16.45 (q),
C, 67.17; H, 7.25. Found: C, 67.02; H, 7.23.
66.12 (t), 102.38 (d), 114.25 (d), 126.28 (d), 128.36 (dϫ2), 128.36 (dϫ2),
4-Benezeneselenenylbut-2-ynal Diethyl Acetal (2b) 76%, pale yellow 136.18 (s), 137.09 (s), 152.45 (d); high-resolution mass calcd for
oil, IR (film, cmϪ1) n 2200 (acetylene); 1H-NMR (500 MHz, CDCl3) d: 1.19 C13H16OS2: 252.0643, found m/z 252.0629.
(6H, t, Jϭ7 Hz, Meϫ2), 3.47—3.53 (2H, m, CH2), 3.55 (2H, d, Jϭ2 Hz,
(1Z,3E)-1,2-Bis(benzenesulfenyl)-4-ethoxybuta-1,3-diene (6) 64%,
SeCH2), 3.60—3.67 (2H, m, CH2), 5.24 (1H, t, Jϭ2 Hz, CH), 7.26—7.30 yellow oil, IR (film, cmϪ1) n 1620, 1180, 1080 (C–O); 1H-NMR (500 MHz,
(3H, m, ArH), 7.57—7.60 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: CDCl3) d: 1.23 (3H, t, Jϭ7 Hz, Me), 3.79 (2H, q, Jϭ7 Hz, OCH2), 6.01 (1H,
12.64 (qϫ2), 15.25 (tϫ2), 60.90 (t), 79.15 (s), 82.75 (s), 91.53 (d), 127.90 d, Jϭ12 Hz, olefinic H), 6.50 (1H, s, olefinic H), 7.05 (1H, d, Jϭ12 Hz,
(d), 129.27 (dϫ2), 129.58 (s), 133.66 (dϫ2); EI-MS m/z 298 (Mϩ). Anal. olefinic H), 7.20—7.40 (10H, m, ArH); 13C-NMR (125 MHz, CDCl3) d:
Calcd for C14H18O2Se: C, 56.57; H, 6.10. Found: C, 56.18; H, 6.14.
14.66 (q), 66.15 (t), 101.87 (d), 125.97 (d), 126.69 (d), 126.74 (d), 128.03
Preparations of 3,4-Diorganylchalcogenobut-3-enal Acetals 4a—d (s), 128.15 (dϪ2), 128.94 (dϫ2), 129.10 (dϫ2), 129.14 (dϫ2), 135.47 (s),
(Typical Procedure) 4-Benzenesulfenylbut-2-ynal diethyl acetal (2a) 136.19 (s), 153.61 (d); EI-MS m/z 314 (small Mϩ). Anal. Calcd for
(4.30 g, 17.1 mmol) was added dropwise to an EtOH (100 ml) solution of C18H18OS2: C, 68.75; H, 5.77. Found: C, 68.32; H, 5.68.
EtONa (prepared from Na (3.90 g, 0.17 mol) and EtOH (100 ml)). The reac-
(1Z,3E)- and (1E,3E)-1-(Benzeneselenenyl)-4-ethoxy-2-(methane-
tion mixture was stirred for 30 min. Then the 15% NaSMe water solution sulfenyl)buta-1,3-diene (7) 92%, 1Z : 1Eϭ77 : 23, The stereochemistry of
(20.0 ml) was added to the mixture. The whole was refluxed for 4 h and then each isomer was determined by the NOE experiments. Irradiation of the
poured into water (300 ml). The organic layer was separated and the aqueous olefinic H of the 1E isomer at d 6.63 ppm increased the intensity of the
layer was extracted with ether. The combined organic layer was dried over methanesulfenyl group. Yellow oil, IR (film, cmϪ1) n 1220—1000 (C–O);
MgSO4. The solvent was removed under reduced pressure. The residue was 1H-NMR (500 MHz, CDCl3) d: 1.29 (t, Jϭ7 Hz, E-Me), 1.32 (t, Jϭ7 Hz, Z-
purified by column chromatography on silica gel eluting with AcOEt–n- Me), 2.28 (s, E-SMe), 2.32 (s, Z-Me), 3.83 (q, Jϭ7 Hz, E-OCH2), 3.87 (2H,
hexane (1 : 20). 3Z- and 3E-4-Benzenesulfenyl-3-(methanesulfenyl)but-3- q, Jϭ7 Hz, Z-OCH2), 5.56 (q, Jϭ12 Hz, E-olefinic H), 5.98 (d, Jϭ12 Hz, Z-
enal diethyl acetal (4a) (4.95 g, 97%) was obtained as a pale yellow oil. The olefinic H), 6.21 (s, Z-olefinic H), 6.63 (s, E-olefinic H), 6.89 (d, Jϭ12 Hz,
stereochemistries of 3Z and 3E-isomers were determined by NOE experi- E-olefinic H), 7.07 (d, Jϭ12 Hz, Z-olefinic H), 7.21—7.36 (3H, m, ArH),
ments irradiating the olefinic H of E-isomer at d 5.89 ppm. The intensity of 7.42—7.49 (1H, m, ArH), 7.53—7.62 (1H, m, ArH); 13C-NMR of (1Z,3E)
the methylsulfenyl group was increased; however, that of Z-isomer could not (125 MHz, CDCl3) d: 14.95 (q), 16.35 (q), 66.20 (t), 103.94 (d), 110.56 (d),
be observed. IR (film, cmϪ1) n 1120, 1060 (C–O); 1H-NMR (500 MHz, 126.95 (d), 129.42 (dϫ2), 131.25 (dϫ2), 135.79 (s), 136.63 (s), 152.55 (d);
CDCl3) d: 1.21 (t, Jϭ7 Hz, Z- and E-Me), 2.33 (s, Z-SMe), 2.34 (s, E-SMe), EI-MS m/z 300 (Mϩ). Anal. Calcd for C13H16OSSe: C, 52.17; H, 5.39.
2.67 (dd, Jϭ1, 6 Hz, Z-CH2), 2.87 (d, Jϭ6 Hz, E-CH2), 3.50—3.57 (m,
OCH2), 3.65—3.73 (m, OCH2), 4.73 (t, Z-CHO), 4.75 (t, Jϭ6 Hz, CHO),
Found: C, 51.97; H, 5.26.
(1Z,3E)-1-(Benzeneselenenyl)-2-(benzenesulfenyl)-4-ethoxybuta-1,3-
5.89 (s, E-olefinic H), 6.41 (d, Jϭ6 Hz, Z-olefinic H), 7.19—7.40 (m, ArH); diene (8) 65%, yellow oil, IR (film, cmϪ1) n 1180, 1020 (C–O); H-NMR
1
EI-MS m/z 298 (Mϩ). Anal. Calcd for C15H22O2S2: C, 60.37; H, 7.43. Found:
C, 60.16; H, 7.28.
(500 MHz, CDCl3) d: 1.22 (3H, t, Jϭ7 Hz, Me), 3.77 (2H, q, Jϭ7 Hz,
OCH2), 5.88 (1H, d, Jϭ12 Hz, olefinic H), 6.77 (1H, s, olefinic H), 7.05 (1H,
3Z- and 3E-3,4-Bis(benzenesulfenyl)but-3-enal Diethyl Acetal (4b) d, Jϭ12 Hz, olefinic H), 7.13—7.16 (1H, m, ArH), 7.23—7.30 (7H, m,
1
73%, yellow oil, IR (film, cmϪ1) n 1120, 1060 (C–O); H-NMR (500 MHz, ArH), 7.47—7.49 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: 14.66 (q),
CDCl3) d: 1.15 (t, Jϭ7 Hz, Z-Me), 1.20 (t, Jϭ7 Hz, E-Me), 2.57 (d, Jϭ5 Hz, 66.25 (t), 103.20 (d), 124.07 (d), 126.02 (d), 127.25 (d), 128.33 (dϫ2),
Z-CH2), 2.79 (d, Jϭ6 Hz, E-CH2), 3.38—3.45 (m, OCH2), 3.58—3.62 (m, 128.93 (dϫ2), 129.29 (dϫ2), 129.38 (s), 130.78 (s), 131.86 (dϫ2), 136.01
OCH2), 4.66 (t, Jϭ5 Hz, Z-CHO), 4.80 (t, Jϭ6 Hz, E-CHO), 6.54 (s, E-
olefinic H), 6.77 (s, Z-olefinic H), 7.20—7.42 (m, ArH); EI-MS m/z 360
(Mϩ). Anal. Calcd for C20H24O2S2: C, 66.63; H, 6.71. Found: C, 66.66; H,
(s), 153.89 (d); EI-MS m/z 362 (Mϩ). Anal. Calcd for C18H18OSSe: C,
59.83; H, 5.02. Found: C, 59.35; H, 4.89.
Lithiation and Reaction of 1,3-Butadienes with Aldehydes (Typical

December 2003
1409
Procedure) Under an Ar atmosphere, a n-BuLi was added dropwise C23H28O2S2: 400.1531, found m/z 400.1535.
to
a
THF (6 ml) solution of (1Z,3E)-4-ethoxy-2-(methylsulfenyl)-1-
(2E,4E)-2,3-Bis(benzenesulfenyl)-5-ethoxy-1-phenylpenta-2,4-dien-1-
(phenylsulfenyl)-1,3-butadiene (5) (0.35 g, 1.38 mmol) and 1,4-diazabicy- ol (13b) 68%, yellow oil, IR (film, cmϪ1) 3460 (OH), 1620, 1190 (C–O);
clo[2.2.2]octane (0.78 g, 6.92 mmol) at Ϫ30 °C. The reaction mixture was 1H-NMR (500 MHz, CDCl3) d: 1.03 (3H, t, Jϭ7 Hz, Me), 2.95 (1H, d,
stirred for 10 min and then cooled at Ϫ50 °C. A THF (2 ml) solution of the Jϭ9 Hz, OH), 3.45—3.55 (2H, m, OCH2), 6.18 (1H, d, Jϭ12 Hz, olefinic
corresponding aldehydes was added to the mixture. The whole was stirred H), 6.67 (1H, d, Jϭ9 Hz, CHO), 7.12—7.26 (9H, m, olefinic and ArH),
for 10 min and poured into water (100 ml). The organic layer was separated 7.38—7.40 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: 14.30 (q), 65.77
and the aqueous layer was extracted with ether. The combined organic layer (t), 73.69 (d), 104.65 (d), 125.76 (d), 125.92 (dϫ2), 126.02 (d), 127.23 (d),
was dried over MgSO4. The solvent was removed under reduced pressure. 127.89 (dϫ2), 128.03 (dϫ2), 128.06 (dϫ2), 128.75 (dϫ2), 129.01 (dϫ2),
The residue was purified by column chromatography on silica gel eluting 135.89 (s), 136.25 (s), 136.33 (s), 137.59 (s), 141.98 (s), 156.42 (d); high-
with AcOEt–n-hexane (1 : 20) to give (4E,6E)-4-benzenesulfenyl-7-ethoxy- resolution mass calcd for C25H24O2S2: 420.1218, found m/z 420.1211.
5-(methanesulfenyl)-2,2-dimethylhepta-4,6-dien-3-ol (9a) (0.28 g, 60%) as a
(1E,4E,6E)-4,5-Bis(benzenesulfenyl)-7-ethoxy-1-phenylhepta-1,4,6-
yellow oil. IR (film, cmϪ1) n 3480 (OH); 1H-NMR (500 MHz, CDCl3) d: trien-3-ol (13c) 63%, yellow oil, IR (film, cmϪ1) n 3250 (OH), 1610, 1200
0.97 (9H, s, Meϫ3), 1.18 (3H, t, Jϭ7 Hz, Me), 2.22 (3H, s, SMe), 2.73 (1H, (C–O); 1H-NMR (500 MHz, CDCl3) d: 1.10 (3H, t, Jϭ7 Hz, Me), 2.72 (1H,
d, Jϭ11 Hz, OH), 3.56—3.59 (1H, m, OCH2), 3.67—3.70 (1H, m, OCH2), d, Jϭ9 Hz, OH), 3.60 (2H, q, Jϭ7 Hz, OCH2), 6.07—6.12 (2H, m, CHO and
5.27 (1H, d, Jϭ11 Hz, OCH2), 5.92 (1H, d, Jϭ13 Hz, olefinic H), 7.10 (1H, olefinic H), 6.30 (1H, d, Jϭ12 Hz, olefinic H), 6.49 (1H, d, Jϭ14 Hz,
d, Jϭ13 Hz, olefinic H), 7.09—7.12 (2H, m, ArH), 7.21—7.26 (3H, m,
ArH); 13C-NMR (125 MHz, CDCl3) d: 14.48 (q), 18.42 (q), 26.67 (qϫ3), CDCl3) d: 14.42 (q), 66.06 (t), 73.52 (d), 105.10 (d), 125.92 (d), 126.07 (d),
37.56 (s), 65.57 (t), 78.27 (d), 103.95 (d), 125.33 (d), 126.78 (dϫ2), 128.84 126.48 (dϫ2), 127.50 (d), 127.94 (dϫ2), 127.97 (dϫ2), 128.33 (dϫ2),
(dϫ2), 132.80 (s), 137.36 (s), 141.86 (s), 155.25 (d); m/z 400 (Mϩ). Anal. 128.97 (dϫ2), 129.11 (dϫ2), 129.64 (d), 130.61 (d), 136.01 (s), 136.38 (s),
Calcd for C18H26O2S2: C, 63.86; H, 7.74. Found: C, 63.48; H, 7.46. The 136.52 (s), 136.61 (s), 136.73 (s), 156.51 (d); high-resolution mass calcd for
olefinic H), 7.11—7.38 (16H, m, olefinic and ArH); 13C-NMR (125 MHz,
NOE enhancement of 9a was observed 3% at the a-H of the hydroxy group C27H26O2S2: 446.1374, found m/z 446.1440.
by irradiating the methyl protons of the methanesulfenyl group at d
2.22 ppm.
Preparation of 2-(Benzeneselenenyl)-5-ethoxy-3-(methanesulfenyl)-1-
phenylpenta-2,4-dien-1-ol (15a) (Method B) (Typical Procedure) n-
(4E,6E)-4-(Benzenesulfenyl)-5-(methanesulfenyl)-2,2-dimethylun-
BuLi (1.70 ml, 2.51 mmol) was added to a THF (3.0 ml) solution of 2,2,6,6-
deca-4,6-dien-3-ol (10) 10%, pale yellow oil, IR (film, cmϪ1) n 3480 cmϪ1 tetramethylpiperidine (0.35 g, 2.51 mmol) and t-BuOK (0.28 g, 2.51 mmol)
1
(OH); H-NMR (500 MHz, CDCl3) d: 0.80 (3H, t, Jϭ7 Hz, Me), 0.98 (9H, at Ϫ78 °C under an Ar atmosphere. The mixture was stirred for 10 min, and
s, Meϫ3), 1.07—1.32 (4H, m, CH2), 1.94—2.11 (2H, m, CH2), 2.17 (3H, s, then a THF (2 ml) solution of 1-benzeneselenenyl-4-ethoxy-2-methane-
SMe), 2.80 (1H, d, Jϭ11 Hz, OH), 5.24 (1H, d, Jϭ11 Hz, CHO), 6.19 (1H, sulfenylbuta-1,3-diene (7) (0.25 g, 0.84 mmol) was added dropwise to the
dt, Jϭ7, 15 Hz, olefinic H), 6.40 (1H, dt, Jϭ15, 1 Hz, olefinic H), 7.07—
mixture. A THF (1.0 ml) solution of benzaldehyde (0.27 g, 2.51 mmol) was
7.12 (1H, m, ArH), 7.13—7.30 (3H, m, ArH), 7.38—7.41 (1H, m, ArH); EI- added to the reaction mixture. The whole was stirred for 10 min and poured
MS m/z 350 (Mϩ). Anal. Calcd for C20H30OS2: C, 68.52; H, 8.63. Found: C,
68.88; H, 8.47.
into water (100 ml). The organic layer was separated and the aqueous layer
was extracted with ether. The combined organic layer was dried over
MgSO4. The solvent was removed under reduced pressure. The residue was
(2E,4E)-2-(Benzenesulfenyl)-5-ethoxy-3-(methanesulfenyl)-1-
mesitylpenta-2,4-dien-1-ol (9b) 57%, pale yellow oil, IR (film, cmϪ1) n purified by preparative TLC on silica gel eluting with AcOEt–n-hexane
1
3450 (OH), 1610, 1190 (C–O); H-NMR (500 MHz, CDCl3) d: 1.18 (3H, t,
Jϭ7 Hz, Me), 2.04 (3H, s, Me), 2.15 (3H, s, Me), 2.37 (6H, s, Meϫ2), 3.04
(1H, br s, OH), 3.57—3.61 (1H, m, OCH2), 3.68—3.71 (1H, m, OCH2), 6.06
(1 : 20). The title compound (0.17 g, 54%) was obtained as a yellow oil.
15a: IR (film, cmϪ1) n 3450 (OH), 1610, 1180 (C–O); 1H-NMR
(500 MHz, CDCl3) d: 1.17 (3H, t, Jϭ7 Hz, Me), 2.29 (3H, s, Me), 2.96 (1H,
(1H, d, Jϭ12 Hz, olefinic H), 6.49 (1H, d, Jϭ5 Hz, CHO), 6.75 (2H, s, d, Jϭ9 Hz, OH), 3.57—3.65 (2H, m, OCH2), 5.98 (1H, d, Jϭ12 Hz, olefinic
ArH), 7.05—7.18 (6H, m, olefinic and ArH); 13C-NMR (125 MHz, CDCl3) H), 6.65 (1H, d, Jϭ9 Hz, CHO), 7.10—7.30 (11H, m, olefinic and ArH),
d: 14.51 (q), 18.03 (q), 20.74 (q), 21.41 (qϫ2), 65.60 (t), 73.02 (d), 104.22 7.41—7.43 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: 14.47 (q), 18.67
(d), 125.35 (d), 127.37 (dϫ2), 128.68 (dϫ2), 129.89 (dϫ2), 134.54 (s), (q), 65.53 (t), 73.67 (d), 105.43 (d), 125.79 (dϫ2), 126.16 (d), 127.14 (d),
135.25 (s), 136.57 (s), 136.86 (sϫ2), 137.27 (s), 141.01 (s), 154.76 (d); 128.12 (dϫ2), 128.94 (dϫ2), 130.03 (dϫ2), 131.74 (s), 135.79 (s), 138.75
high-resolution mass calcd for C23H28O2S2: 400.1531, found m/z 400.1512.
(2E,4E)-2-(Benzenesulfenyl)-5-ethoxy-3-(methanesulfenyl)-1-
(s), 142.61 (s), 155.36 (d); MS m/z 406 (small Mϩ).
(1E,4E,6E)-4-(Benzeneselenenyl)-7-ethoxy-5-(methanesulfenyl)-1-
phenylpenta-2,4-dien-1-ol (9c) 50%, yellow oil, IR (film, cmϪ1) n 3460 phenylhepta-1,4,6-trien-3-ol (15b) 68%, IR (film, cmϪ1) n 3430 (OH);
1
(OH); H-NMR (500 MHz, CDCl3) d: 1.18 (3H, t, Jϭ7 Hz, Me), 2.30 (3H, 1H-NMR (500 MHz, CDCl3) d: 1.18 (3H, t, Jϭ7 Hz, Me), 2.27 (3H, s, Me),
s, SMe), 3.07 (1H, d, Jϭ8 Hz, OH), 3.62—3.70 (2H, m, OCH2), 6.02 (1H, d, 2.91 (1H, br s, OH), 3.61—3.67 (2H, m, OCH2), 6.05 (1H, d, Jϭ12 Hz,
Jϭ12 Hz, olefinic H), 6.61 (1H, d, Jϭ8 Hz, CHO), 7.04—7.33 (9H, m, olefinic H), 6.11 (1H, dd, Jϭ6, 1 Hz, 3-H), 6.20 (1H, dd, Jϭ6, 16 Hz, 2-H),
olefinic and ArH), 7.41—7.42 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) 6.63 (1H, dd, Jϭ16, 1 Hz, 1-H), 7.10—7.26 (9H, m, olefinic and ArH),
d: 14.48 (q), 18.59 (q), 65.70 (t), 73.58 (d), 103.62 (d), 125.47 (d), 125.83
(dϫ2), 127.18 (d), 127.24 (dϫ2), 128.15 (dϫ2), 128.77 (dϫ2), 133.89 (s), (q), 65.45 (t), 73.31 (d), 105.43 (d), 126.05 (d), 126.31 (dϫ2), 127.32 (d),
7.40—7.53 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: 14.33 (q), 18.46
136.35 (s), 140.71 (s), 142.48 (s), 155.56 (d); high-resolution mass calcd for
128.20 (dϫ2), 128.91 (dϫ2), 129.88 (dϫ2), 130.24 (d), 130.29 (d), 131.76
(s), 134.54 (s), 136.52 (s), 138.77 (s), 155.07 (d); EI-MS m/z 432 (small
C20H22O2S2: 358.1061, found m/z 358.1085.
(4E,6E)-4-(Benzenesulfenyl)-7-ethoxy-5-(methanesulfenyl)hepta-4,6- Mϩ).
dien-3-ol (9d) 47%, yellow oil, IR (film, cmϪ1) n 3450 (OH), 1620, 1190
(2E,4E)-2-(Benzeneselenenyl)-3-(benzenesulfenyl)-5-ethoxypenta-2,4-
(C–O); 1H-NMR (500 MHz, CDCl3) d: 0.93 (3H, t, Jϭ7 Hz, Me), 1.20 (3H,
t, Jϭ7 Hz, Me), 1.55—1.69 (4H, m, CH2), 2.27 (3H, s, SMe), 2.45 (1H, d,
dien-1-ol (17a) 67%, yellow oil, IR (film, cmϪ1) n 3450 (OH); H-NMR
1
(500 MHz, CDCl3) d: 1.05 (3H, t, Jϭ7 Hz, Me), 2.83 (1H, d, Jϭ8 Hz, OH),
Jϭ9 Hz, OH), 3.68 (2H, q, Jϭ7 Hz, OCH2), 5.24 (1H, d, Jϭ9 Hz, CHO), 3.46—3.54 (2H, m, OCH2), 6.17 (1H, dd, Jϭ12, 1 Hz, olefinic H), 6.67 (1H,
6.05 (1H, d, Jϭ12 Hz, olefinic H), 7.08—7.11 (1H, m, ArH), 7.16—7.23 d, Jϭ8 Hz, CHO), 7.10—7.14 (5H, m, ArH), 7.19—7.26 (9H, m, olefinic
(6H, m, olefinic and ArH); 13C-NMR (125 MHz, CDCl3) d: 10.27 (q), 14.47 and ArH), 7.31—7.40 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: 14.35
(q), 18.50 (q), 30.25 (t), 65.65 (t), 74.31 (d), 103.76 (d), 125.31 (d), 126.96
(dϫ2), 128.78 (dϫ2), 134.45 (s), 136.68 (s), 140.49 (s), 155.07 (d); high- 127.87 (dϫ3), 128.09 (dϫ2), 128.97 (dϫ3), 130.71 (dϫ2), 131.72 (s),
resolution mass calcd for C16H22O2S2: 310.1061, found m/z 310.1073. 134.41 (s), 136.16 (s), 139.60 (s), 142.15 (s), 156.21 (s); high-resolution
(4E,6E)-4,5-Bis(benzenesulfenyl)-7-ethoxy-2,2-dimethylhepta-4,6- mass calcd for C25H24O2SSe: 468.0662, found m/z 468.0714.
(q), 65.64 (t), 73.88 (d), 106.55 (d), 125.88 (dϫ3), 126.48 (d), 127.24 (d),
dien-3-ol (13a) 56%, pale yellow oil, IR (film, cmϪ1) n 3500 (OH), 1610,
(1E,4E,6E)-4-(Benzeneselenenyl)-5-(benzenesulfenyl)-7-ethoxy-1-
1190 (C–O); 1H-NMR (500 MHz, CDCl3) d; 1.00 (9H, s, Meϫ3), 1.02 (3H, phenylhepta-1,4,6-trien-3-ol (17b) 76%, yellow oil, IR (film, cmϪ1) n
1
t, Jϭ7 Hz, Me), 2.78 (1H, d, Jϭ11 Hz, OH), 3.42—3.46 (1H, m, OCH2), 3420 (OH); H-NMR (500 MHz, CDCl3) d: 1.10 (3H, t, Jϭ7 Hz, Me), 2.65
3.53—3.56 (1H, m, OCH2), 5.30 (1H, d, Jϭ11 Hz, CHO), 6.11 (1H, d, (1H, br s, OH), 3.55—3.59 (2H, m, OCH2), 6.08—6.11 (2H, m, olefinic H
Jϭ12 Hz, olefinic H), 7.01 (1H, d, Jϭ11 Hz, olefinic H), 7.08—7.25 (8H, m, and CHO), 6.28 (1H, d, Jϭ12 Hz, olefinic H), 6.50 (1H, d, Jϭ14 Hz, olefinic
ArH), 7.36—7.37 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d 14.33 (q), H), 7.14—7.25 (14H, m, olefinic and ArH), 7.40—7.42 (2H, m, ArH); 13C-
26.78 (qϫ3), 37.61 (s), 65.66 (t), 78.48 (d), 104.90 (d), 125.86 (d), 125.87 NMR (125 MHz, CDCl3) d: 14.43 (q), 65.91 (t), 73.69 (d), 107.11 (d),
(d), 127.93 (dϫ2), 128.22 (dϫ2), 128.80 (dϫ2), 128.84 (dϫ2), 136.28 (s), 125.95 (d), 126.49 (dϫ2), 126.61 (d), 127.52 (d), 127.83 (dϫ2), 128.34
136.82 (s), 137.40 (s), 137.55 (s), 156.06 (d); high-resolution mass calcd for
(dϫ2), 129.05 (dϫ2), 129.15 (dϫ2), 129.92 (d), 130.67 (d), 130.80 (dϫ2),

1410
Vol. 51, No. 12
131.80 (s), 134.71 (s), 136.31 (s), 136.63 (s), 138.47 (s), 156.23 (d); high-
resolution mass calcd for C27H26O2SSe: 494.0819, found m/z 494.0758.
Reaction of 5-Ethoxy-3-(methanesulfenyl)-2-(benzenesulfenyl)pent-
2,4-dien-1-ol (9a) with SOCl2/pyridine (Typical Procedure) SOCl2
(66 mg, 0.56 mmol) was added dropwise to a CH2Cl2 (3 ml) solution of
(1E,3E)-1-ethoxy-3-(methanesulfenyl)-6,6-dimethyl-4-(benzene-
sulfenyl)hepta-1,3-dien-5-ol (9a) (0.19 g, 0.56 mmol) and pyridine (89 mg,
1.12 mmol) at Ϫ20 °C. The reaction mixture was stirred for 10 min and
poured into a sat. NaHCO3 solution (50 ml). The organic layer was separated
and the aqueous layer was extracted with CHCl3. The combined organic
layer was dried over MgSO4. The solvent was removed under reduced pres-
sure. The residue was purified by preparative TLC on silica gel eluting with
AcOEt–n-hexane (1 : 20) to give 3-(methanesulfenyl)-6,6-dimethyl-4-(ben-
zenesulfenyl)hepta-2,4-dienal (11a) (0.14 g, 85%) as a pale yellow oil. IR
(film, cmϪ1) n 1660 cmϪ1 (CO); 1H-NMR (500 MHz, CDCl3) d: 1.35 (9H, s,
Meϫ3), 2.35 (3H, s, SMe), 6.03 (1H, d, Jϭ7 Hz, olefinic H), 6.31 (1H, s,
olefinic H), 7.21—7.26 (3H, m, ArH), 7.29—7.31 (2H, m, ArH), 9.85 (1H,
d, Jϭ7 Hz, CHO); 13C-NMR (125 MHz, CDCl3) d: 15.60 (q), 30.36 (qϫ3),
34.34 (s), 127.61 (d), 128.78 (dϫ2), 129.47 (d), 131.85 (dϫ2), 132.27 (s),
132.82 (s), 151.46 (d), 163.46 (s), 190.12 (d); MS m/z 292 (Mϩ). Anal.
Calcd for C16H20OS2: C, 65.71; H, 6.89. Found: C, 65.65; H, 6.97.
(2Z,4Z)-4-(Benzenesulfenyl)-3-(methanesulfenyl)-5-mesitylpenta-2,4-
dienal (11b) 37%, yellow oil, IR (film, cmϪ1) n 1670 (CO); 1H-NMR
(500 MHz, CDCl3) d: 2.24 (6H, s, Meϫ2), 2.29 (3H, s, SMe), 2.40 (3H, s,
Me), 6.36 (1H, d, Jϭ7 Hz, 2-H), 6.92 (2H, s, ArH), 7.02 (1H, s, olefinic H),
7.20—7.27 (5H, m, ArH), 9.95 (1H, d, Jϭ7 Hz, CHO); 13C-NMR (125 MHz,
CDCl3) d: 16.16 (q), 20.50 (qϫ2), 21.06 (q), 127.92 (d), 128.29 (dϫ2),
128.75 (dϫ2), 130.32 (d), 131.70 (s), 132.01 (s), 132.31 (dϫ2), 135.46 (s),
136.12 (d), 137.63 (sϫ2), 138.43 (s), 161.86 (s), 190.12 (d); high-resolution
mass calcd for C21H22OS2: 354.1112, found m/z 354.1102.
d: 6.80 (1H, d, Jϭ7 Hz, 2-H), 7.13—7.33 (13H, m, ArH), 7.51—7.53 (2H,
m, ArH), 7.66 (1H, s, olefinic H), 10.20 (1H, d, Jϭ7 Hz, CHO); 13C-NMR
(125 MHz, CDCl3) d: 127.15 (d), 128.15 (dϫ2), 128.18 (d), 128.94 (dϫ2),
129.06 (dϫ2), 129.11 (d), 129.95 (dϫ2), 130.34 (dϫ2), 132.01 (dϫ2),
132.08 (s), 132.35 (s), 133.37 (d), 134.95 (s), 142.35 (d), 158.06 (s), 191.61
(d); high-resolution mass calcd for C23H18OS2: 374.0799, found m/z
374.0834.
(2Z,4Z)-3,4-Bis(benzenesulfenyl)-5-phenylpenta-2,4-dienal Diethyl
Acetal 17%, yellow oil, IR (film, cmϪ1) n 1100, 1040 (C–O); 1H-NMR
(500 MHz, CDCl3) d: 1.09 (6H, t, Jϭ7 Hz, Meϫ2), 3.26—3.31 (1H, m,
OCH2), 3.34—3.39 (1H, m, OCH2), 5.47 (1H, d, Jϭ7 Hz, 1-H), 6.55 (1H, d,
Jϭ7 Hz, 2-H), 7.16—7.32 (13H, m, ArH), 7.44—7.46 (3H, m, olefinic and
ArH); 13C-NMR (125 MHz, CDCl3) d: 15.21 (qϫ2), 61.06 (tϫ2), 99.54 (d),
126.58 (d), 126.91 (d), 127.94 (dϫ2), 128.06 (d), 128.67 (dϫ3), 129.56
(dϫ2), 130.63 (dϫ2), 130.92 (dϫ2), 133.09 (s), 134.16 (s), 134.51 (s),
135.92 (s), 136.98 (d), 138.37 (s), 138.94 (d); EI-MS m/z 448 (Mϩ). Anal.
Calcd for C27H28O2S2: C, 72.28; H, 6.29. Found: C, 72.17; H, 6.21.
(2Z,4Z,6E)-3,4-Bis(benzenesulfenyl)-7-phenylhepta-2,4,6-trienal (14c)
75%, yellow oil, IR (film, cmϪ1) n 1660 (CO); 1H-NMR (500 MHz, CDCl3)
d: 6.91 (1H, d, Jϭ15 Hz, olefinic H), 7.05 (1H, d, Jϭ7 Hz, olefinic H),
7.08—7.47 (15H, m, ArH), 7.52 (1H, dd, Jϭ11, 15 Hz, olefinic H), 7.80
(1H, d, Jϭ11 Hz, olefinic H), 10.26 (1H, d, Jϭ7 Hz, CHO); 13C-NMR
(125 MHz, CDCl3) d: 125.98 (d), 126.77 (d), 127.38 (dϫ2), 127.63 (d),
128.75 (dϫ2), 129.03 (dϫ2), 129.23 (dϫ4), 130.44 (dϫ2), 131.25 (s),
133.43 (s), 134.29 (d), 136.15 (s), 141.29 (d), 145.60 (d), 154.74 (s), 192.56
(d); high-resolution mass calcd for C25H20OS2: 400.0956, found m/z
400.1001.
(2Z,4Z)-4-(Benzeneselenenyl)-3-(methanesulfenyl)-5-phenylpenta-2,4-
dienal (16a) 67%, yellow oil, IR (film, cmϪ1) n 1640 (CO); 1H-NMR
(500 MHz, CDCl3) d: 2.38 (3H, s, SMe), 6.10 (1H, d, Jϭ7 Hz, 2-H), 7.16
(1H, s, olefinic H), 7.19—7.28 (3H, m, ArH), 7.33—7.40 (3H, m, ArH),
7.41—7.43 (2H, m, ArH), 7.56—7.57 (2H, m, ArH), 9.83 (1H, d, Jϭ7 Hz,
CHO); 13C-NMR (125 MHz, CDCl3) d: 15.58 (q), 127.64 (s), 128.27 (dϫ2),
128.56 (dϫ2), 128.69 (d), 128.89 (dϫ2), 129.32 (dϫ2), 131.60 (s), 135.15
(dϫ2), 135.57 (s), 135.65 (d), 162.73 (s), 189.50 (d); MS m/z 360 (Mϩ).
Anal. Calcd for C18H16OSSe: C, 60.16; H, 4.49. Found: C, 60.29; H, 4.59.
The NOE enhancement of the formyl proton (4%) was observed by irradiat-
ing the methanesulfenyl group of (2Z,4Z) isomer.
(2Z,4E)-4-(Benzenesulfenyl)-3-(methanesulfenyl)-5-mesitylpenta-2,4-
) n
dienal (11b) Yellow oil, IR (film, cmϪ1 1670 (CO); 1H-NMR
(500 MHz, CDCl3) d: 2.18 (3H, s, SMe), 2.29 (3H, s, Me), 2.31 (6H, s,
Meϫ2), 5.63 (1H, d, Jϭ8 Hz, 2-H), 7.21—7.27 (3H, m, ArH), 7.38—7.39
(2H, m, ArH), 9.91 (1H, d, Jϭ8 Hz, CHO); 13C-NMR (125 MHz, CDCl3) d:
15.68 (q), 20.42 (qϫ2), 21.09 (q), 123.36 (d), 128.33 (dϫ2), 128.73 (dϫ2),
128.89 (d), 130.79 (s), 131.33 (s), 133.85 (d), 134.54 (dϫ2), 134.57 (s),
135.74 (dϫ2), 137.70 (s), 166.14 (s), 188.53 (d); high-resolution mass calcd
C21H22OS2: 354.1112, found m/z 354.1079.
(2E,4Z)- and (2E,4E)-4-(Benzeneselenenyl)-3-(methanesulfenyl)-5-
phenylpenta-2,4-dienal (16a) 24%, yellow oil, 4Z : 4Eϭ65 : 35, IR (film,
cmϪ1) n 1640 (CO); 1H-NMR (500 MHz, CDCl3) d: 2.10 (s, 4E-SMe), 2.31
(s, 4Z-SMe), 5.49 (d, Jϭ8 Hz, 4E-2-H), 5.66 (d, Jϭ8 Hz, 4Z-2-H), 6.99 (s,
4Z-olefinic H), 7.02 (s, 4E-olefinic H), 7.20—7.44 (m, ArH), 7.53—7.58 (m,
ArH), 7.65—7.67 (m, ArH), 9.32 (d, Jϭ8 Hz, 4Z-CHO), 9.66 (d, Jϭ8 Hz,
4E-CHO); MS m/z 360 (Mϩ). Anal. Calcd for C18H16OSSe: C, 60.16; H,
4.49. Found: C, 59.84; H, 4.64. The stereochemistries of the isomers were
determined by NOE experiments. Irradiation of the methanesulfenyl group
at d 2.10 or 2.31 ppm increased the intensities of the 2-H, (10%) respec-
tively.
(2Z,4Z)-4-(Benzenesulfenyl)-3-(methanesulfenyl)-5-phenylpenta-2,4-
dienal (11c) 59%, yellow oil, IR (film, cmϪ1) n 1660 (CO); 1H-NMR
(500 MHz, CDCl3) d: 2.41 (3H, s, Me), 6.31 (1H, d, Jϭ7 Hz, 2-H), 7.19—
7.43 (9H, m, olefinic and ArH), 7.76—7.78 (2H, m, ArH), 9.95 (1H, d,
Jϭ7 Hz, CHO); 13C-NMR (125 MHz, CDCl3) d: 16.07 (q), 127.95 (d),
128.41 (dϫ2), 128.94 (dϫ2), 129.03 (d), 129.99 (dϫ2), 130.21 (d), 132.00
(dϫ2), 132.35 (s), 133.37 (s), 134.91 (s), 137.42 (d), 162.57 (s), 190.28 (d);
high-resolution mass calcd for C18H16OS2: 312.0643, found m/z 312.0595.
(2Z,4Z)-4-(Benzenesulfenyl)-3-(methanesulfenyl)hepta-2,4-dienal
(11d) 37%, yellow oil, IR (film, cmϪ1) n 1660 (CO); 1H-NMR (500 MHz,
CDCl3) d: 1.12 (3H, t, Jϭ7 Hz, Me), 2.31 (3H, s, SMe), 2.52—2.59 (2H, m,
CH2), 6.24 (1H, d, Jϭ7 Hz, 2-H), 6.50 (1H, t, Jϭ7 Hz, 5-H), 7.18—7.28
(5H, m, ArH), 9.96 (1H, d, Jϭ7 Hz, CHO); 13C-NMR (125 MHz, CDCl3) d:
13.48 (q), 16.18 (q), 23.92 (t), 127.26 (d), 128.87 (dϫ2), 129.93 (d), 130.91
(dϫ2), 132.34 (s), 133.20 (s), 145.45 (d), 190.47 (d); EI-MS m/z 264 (Mϩ).
Anal. Calcd for C14H16OS2: C, 63.59; H, 6.10. Found: C, 63.37; H, 6.08.
(2E,4Z)- and (2E,4E)-4-(Benzenesulfenyl)-3-(methanesulfenyl)hepta-
2,4-dienal (11d) 15%, yellow oil, 2Z : 4Eϭ41 : 59, IR (film, cmϪ1) n 1660
(CO); 1H-NMR (500 MHz, CDCl3) d: 0.98 (t, Jϭ7 Hz, 4Z-Me), 1.12 (t,
Jϭ7 Hz, 4E-Me), 2.09—2.12 (m, 4E-CH2), 2.18 (s, 4Z-SMe), 2.29 (s, 4E-
SMe), 2.49—2.55 (m, 4Z-CH2), 5.66 (d, Jϭ7 Hz, 4Z-2-H), 5.73 (d, Jϭ8 Hz,
4E-2-H), 6.06 (t, Jϭ7 Hz, 4E-5-H), 6.13 (t, Jϭ7 Hz, 4Z-5-H), 7.25—7.39
(m, ArH), 7.47—7.49 (m, ArH), 9.29 (d, Jϭ8 Hz, 4E-CHO), 9.54 (d,
Jϭ7 Hz, 4Z-CHO); high-resolution mass calcd for C14H16OS2: 264.0643,
found m/z 264.0613.
(2Z,4Z)-3,4-Bis(benzenesulfenyl)-6,6-dimethylhepta-2,4-dienal (14a)
70%, yellow oil, IR (film, cmϪ1) n 1660 (CO); 1H-NMR (500 MHz, CDCl3)
d: 1.10 (9H, s, Meϫ3), 6.42 (1H, d, Jϭ7 Hz, 2-H), 6.60 (1H, s, olefinic H),
7.16—7.25 (5H, m, ArH), 7.32—7.33 (5H, m, ArH), 10.09 (1H, d, Jϭ7 Hz,
CHO); 13C-NMR (125 MHz, CDCl3) d: 29.96 (qϫ3), 34.18 (s), 127.03 (d),
128.37 (d), 128.78 (dϫ2), 128.81 (dϫ2), 130.67 (dϫ2), 131.06 (s), 131.83
(d), 131.96 (s), 133.29 (dϫ2), 133.74 (s), 155.91 (d), 160.09 (s), 191.18 (d);
high-resolution mass calcd for C21H22OS2: 354.1112, found m/z 354.1128.
(2Z,4Z)-3,4-Bis(benzenesulfenyl)-5-phenylpenta-2,4-dienal (14b)
67%, yellow oil, IR (film, cmϪ1) n 1650 (CO); 1H-NMR (500 MHz, CDCl3)
(2E,4Z,6E)- and (2E,4Z,6E)-4-(Benzeneselenenyl)-3-(methanesul-
fenyl)-7-phenylhepta-2,4,6-trienal (16b) 53%, yellow oil, 2Z : 2Eϭ
1
83 : 17, IR (film, cmϪ1) n 1640 (CO); H-NMR (500 MHz, CDCl3) d: 2.16
(t, 2Z-SMe), 2.30 (s, 2E-SMe), 5.65 (d, Jϭ8 Hz, 2Z-olefinic H), 5.80 (d,
Jϭ8 Hz, 2E-olefinic H), 6.68—6.70 (m, 2E-olefinic H), 6.78 (dd, Jϭ11,
15 Hz, 2Z-olefinic H), 7.21—7.35 (m, olefinic and ArH), 7.44—7.55 (m,
ArH), 9.35 (d, Jϭ8 Hz, 2E-CHO), 9.45 (d, Jϭ8 Hz, 2Z-CHO); MS m/z 386
(Mϩ). Anal. Calcd for C18H16OSSe: C, 60.16; H, 4.49. Found: C, 59.84; H,
4.64.
(2Z,4Z)-4-(Benzeneselenenyl)-3-(benzenesulfenyl)-5-phenylpenta-2,4-
dienal (18a) 73%, yellow oil, IR (film, cmϪ1) n 1660 (CO); 1H-NMR
(500 MHz, CDCl3) d: 6.57 (1H, d, Jϭ8 Hz, 2-H), 7.16—7.33 (15H, m,
ArH), 7.50 (1H, s, olefinic H), 10.11 (1H, d, Jϭ8 Hz, CHO); 13C-NMR
(125 MHz, CDCl3) d: 127.91 (d), 127.98 (dϫ2), 128.31 (d), 128.59 (d),
128.71 (s), 128.93 (dϫ2), 128.96 (dϫ2), 129.28 (dϫ2), 131.26 (s), 131.81
(s), 132.32 (d), 132.85 (dϫ2), 133.75 (dϫ2), 135.78 (s), 140.82 (d), 159.28
(s), 190.99 (d); MS m/z 422 (Mϩ). Anal. Calcd for C23H18OSSe: C, 65.55; H,
4.31. Found: C, 65.04; H, 4.23.
(2Z,4Z)-4-(Benzeneselenenyl)-3-(benzenesulfenyl)-5-phenylpenta-2,4-
dienal Diethyl Acetal (27) 12%, yellow oil, IR (film, cmϪ1) n 1120, 1050
(C–O); 1H-NMR (500 MHz, CDCl3) d: 1.11 (6H, t, Jϭ7 Hz, Meϫ2), 3.26—
3.29 (1H, m, OCH2), 3.35—3.38 (1H, m, OCH2), 5.44 (1H, d, Jϭ7 Hz,
CHO), 6.41 (1H, d, Jϭ7 Hz, olefinic H), 7.18—7.41 (16H, m, olefinic and
ArH); 13C-NMR (125 MHz, CDCl3) d: 15.19 (qϫ2), 61.01 (tϫ2), 99.44 (d),
126.90 (d), 127.19 (d), 127.76 (dϫ3), 128.55 (dϫ2), 128.72 (dϫ2), 129.10

December 2003
1411
(Mϩ). Anal. Calcd for C23H18OS2: C, 73.76; H, 4.84. Found: C, 73.68; H,
4.75.
(dϫ2), 129.78 (s), 131.35 (dϫ2), 132.66 (s), 133.60 (dϫ2), 133.96 (s),
136.19 (d), 136.78 (s), 138.49 (d), 139.40 (d); MS m/z 496 (Mϩ). Anal.
Calcd for C27H28O2SSe: C, 65.44; H, 5.70. Found: C, 65.52; H, 5.40.
(2E,4Z,6E)- and (2E,4E,6E)-4-(Benzeneselenenyl)-3-(benzenesul-
fenyl)-7-phenylhepta-2,4,6-trienal (18b) 26%, orange powders, mp
120—126 °C, 4Z : 4Eϭ72 : 28, IR (film, cmϪ1) n 1650 (CO); 1H-NMR
(500 MHz, CDCl3) d: 5.33 (d, Jϭ8 Hz, 4Z-2-H), 5.48 (d, Jϭ7 Hz, 4E-2-H),
6.60 (d, Jϭ15 Hz, 4E-olefinic H), 6.75—6.88 (m, 4Z- and 4E-olefinic H),
7.26—7.42 (m, olefinic and ArH), 7.47—7.69 (m, ArH), 9.35 (d, Jϭ7 Hz,
4E-olefinic H), 9.49 (d, Jϭ8 Hz, 4Z-olefinic H); MS m/z 446 (Mϩ).
Preparations of Penta-2,4-dienal Acetals (Typical Procedure) p-
Toluenesulfonic acid (50 mg, 0.1 mmol) was added to a EtOH (5.0 ml) solu-
tion of (4E,6E)-4,5-bis(benzenesulfenyl)-7-ethoxy-2,2-dimethylhepta-4,6-
dien-3-ol (13a) (0.52 g, 1.31 mmol) and triethylorthoformate (0.97 g,
6.55 mmol) at 0 °C. The mixture was stirred for 30 min and poured into
water. The organic layer was separated and the aqueous layer extracted with
ether. The combined organic layer was dried over MgSO4. The solvent was
removed under reduced pressure. The residue was purified by column chro-
matography on silica gel eluting with AcOEt–n-hexane (1 : 50). (2Z,4Z)-3,4-
bis-(benzenesulfenyl)-6,6-dimethylhepta-2,4-dienal diethyl acetal (25)
(0.33 g, 59%) was obtained as a pale yellow oil. IR (film, cmϪ1) n 1100,
(2Z,4Z,6E)-4-(Benzeneselenenyl)-3-(benzenesulfenyl)-7-phenylhepta-
2,4,6-trienal (18b) 39%, orange powders, mp 107—110 °C, IR (KBr,
1
cmϪ1) n 1650 (CO); H-NMR (500 MHz, CDCl3) d: 6.87 (1H, d, Jϭ15 Hz,
1
1050 (C–O); H-NMR (500 MHz, CDCl3) d: 1.05 (6H, t, Jϭ7 Hz, Meϫ2),
olefinic H), 7.04 (1H, d, Jϭ7 Hz, 2-H), 7.14—7.49 (16H, m, olefinic and
ArH), 7.70 (1H, d, Jϭ11 Hz, olefinic H), 10.25 (1H, d, Jϭ7 Hz, CHO); 13C-
NMR (125 MHz, CDCl3) d: 127.30 (dϫ2), 127.36 (d), 127.52 (d), 127.89
(d), 128.72 (dϫ2), 129.12 (d), 129.19 (dϫ2), 129.23 (dϫ2), 129.81 (s),
130.49 (dϫ2), 130.80 (s), 131.96 (dϫ2), 133.42 (s), 135.08 (d), 136.19 (s),
140.81 (d), 145.16 (d), 155.73 (s), 192.37 (d); high-resolution mass calcd for
C25H20OSSe: 448.0400, found m/z 448.0397.
1.08 (9H, s, Meϫ3), 3.14—3.36 (2H, m, OCH2), 5.37 (1H, d, Jϭ7 Hz, 2-H),
6.07 (1H, d, Jϭ7 Hz, CHO), 6.37 (1H, s, 5-H), 7.12—7.27 (3H, m, ArH),
7.30—7.32 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: 15.17 (qϫ2),
30.21 (qϫ3), 33.59 (s), 60.66 (tϫ2), 99.09 (d), 126.38 (d), 127.11 (d),
128.34 (dϫ2), 128.52 (dϫ2), 130.93 (dϫ2), 131.33 (s), 132.47 (dϫ2),
133.79 (s), 133.90 (d), 134.86 (s), 140.13 (s), 152.14 (d); MS m/z 428 (Mϩ).
Anal. Calcd for C25H32O2S2: C, 70.05; H, 7.52. Found: C, 70.16; H, 7.49.
Reaction of Acetal with Nucleophiles (Typical Procedure) BF3–Et2O
(33 mg, 0.23 mmol) was added dropwise to a CH2Cl2 (1.0 ml) solution of
(2Z,4Z)-3,4-bis(benzenesulfenyl)-6,6-dimethylhepta-2,4-dienal diethyl ac-
etal (25) (0.10 g, 0.23 mmol) and 1-phenyl-1-trimethylsilyloxyethylene
(0.16 g, 0.70 mmol) at Ϫ50 °C under an Ar atmosphere. The reaction mix-
ture was stirred for 10 min and poured into sat. NaHCO3 solution (100 ml).
The organic layer was separated and the aqueous layer was extracted with
CHCl3. The combined organic layer was dried over MgSO4. The solvent was
removed under reduced pressure. The residue was purified by preparative
TLC on silica gel eluting with AcOEt–n-hexane (1 : 50). (4Z,6Z)-5,6-
(2Z,4Z,6E)-4-(Benzeneselenenyl)-3-(benzenesulfenyl)-7-phenylhepta-
2,4,6-trienal Diethyl Acetal 12%, yellow oil, IR (film, cmϪ1) n 1120,
1
1050 (C–O); H-NMR (500 MHz, CDCl3) d: 1.10 (6H, t, Jϭ7 Hz, Meϫ2),
3.30—3.36 (1H, m, OCH2), 3.40—3.46 (1H, m, OCH2), 5.52 (1H, d,
Jϭ7 Hz, CHO), 6.71 (1H, d, Jϭ14 Hz, olefinic H), 6.82 (1H, d, Jϭ7 Hz, 2-
H), 7.13—7.46 (17H, m, olefinic and ArH); MS m/z 522 (Mϩ).
(2Z,4Z,6Z,8Z)-3,4,7,8-Tetrakis(benzenesulfenyl)-10,10-dimethylun-
deca-2,4,6,8-tetraenal (20) 45%, yellow oil, IR (film, cmϪ1) n 1660 (CO);
1H-NMR (500 MHz, CDCl3) d: 1.09 (9H, s, Meϫ3), 6.71 (1H, s, olefinic
H), 6.91—7.28 (21H, m, olefinic and ArH), 7.60 (1H, d, Jϭ7 Hz, olefinic
H), 8.26 (1H, d, Jϭ11 Hz, olefinic H), 10.21 (1H, d, Jϭ7 Hz, CHO); 13C-
NMR (125 MHz, CDCl3) d: 30.19 (qϫ3), 34.04 (s), 126.36 (d), 126.88 (d),
127.40 (d), 127.70 (d), 128.55 (dϫ2), 128.63 (dϫ2), 128.95 (d), 129.03
(dϫ2), 129.79 (dϫ2), 130.21 (dϫ2), 131.38 (s), 131.44 (dϫ2), 131.83
(dϫ2), 132.79 (s), 132.83 (d), 133.45 (s), 134.01 (s), 134.07 (s), 134.20 (d),
134.59 (s), 142.33 (d), 145.81 (s), 154.97 (d), 155.22 (s), 192.38 (d); high-
resolution mass calcd for C37H34OS4: 622.1493, found m/z 622.1493. Anal.
Calcd for the 2,4-dinitrophenylhydrazone: orange needles, mp 178—182 °C,
C: 64.31; H, 4.77; N, 6.98. Found: C, 63.97; H, 4.81; N, 6.86. The interme-
diacy, 11-ethoxy-2,2-dimethyl-4,5,8,9-tetrakis(phenylsulfenyl)undec-
3,5,8,9-tetraen-7-ol (19) was obtained in 49% yield as the mixture with a
small amount of the aldehyde 20. The spectral data is shown as follows. IR
(film, cmϪ1) n 3550 (OH); 1H-NMR (500 MHz, CDCl3) d: 1.02 (9H, s,
Meϫ3), 1.05 (3H, t, Jϭ7 Hz, Me), 2.44 (1H, d, Jϭ8 Hz, OH), 3.54 (2H, q,
Jϭ7 Hz, OCH2), 6.16—6.20 (3H, m, olefinic H), 6.35 (1H, t, Jϭ8 Hz,
CHOH), 7.06—7.39 (22H, m, olefinic and ArH); 13C-NMR (125 MHz,
CDCl3) d: 14.33 (q), 30.07 (qϫ3), 33.42 (s), 65.84 (t), 71,47 (d), 104.64 (d),
125.66 (d), 125.82 (d), 126.28 (d), 126.85 (d), 127.64 (dϫ2), 128.06 (dϫ2),
128.16 (dϫ2), 128.38 (dϫ2), 128.78 (dϫ2), 128.83 (dϫ2), 130.67 (dϫ2),
131.23 (s), 132.39 (dϫ2), 133.89 (s), 134.80 (s), 135.93 (s), 135.98 (s),
136.33 (d), 136.63 (s), 137.16 (s), 138.50 (s), 151.27 (d), 156.24 (d); MS
m/z 325, 297, 272.
bis(benzenesulfenyl)-3-ethoxy-8,8-dimethylnona-4,6-dienophenone
(26)
(60 mg, 51%) was obtained as a yellow oil. IR (film, cmϪ1) n 1690 (CO);
1H-NMR (500 MHz, CDCl3) d: 0.94 (3H, t, Jϭ7 Hz, Me), 1.09 (9H, s,
Meϫ3), 2.66 (1H, dd, Jϭ5, 15 Hz, 2-H), 2.96—2.99 (1H, m, OCH2), 3.08—
3.13 (2H, m, 2-H and OCH2), 4.94—5.04 (1H, m, 3-H), 6.07 (1H, d,
Jϭ9 Hz, 4-H), 6.31 (1H, s, 7-H), 7.08—7.30 (10H, m, ArH), 7.40—7.54
(3H, m, ArH), 7.85—7.87 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d:
15.18 (q), 30.30 (qϫ3), 33.58 (s), 44.26 (t), 63.98 (t), 73.33 (d), 126.48 (d),
127.11 (d), 127.67 (s), 128.25 (dϫ2), 128.42 (dϫ2), 128.45 (dϫ2), 128.49
(dϫ2), 131.18 (dϫ2), 131.43 (s), 132.27 (dϫ2), 132.87 (d), 134.10 (s),
137.19 (s), 138.28 (d), 151.32 (d), 197.06 (s); MS m/z 502 (Mϩ). Anal.
Calcd for C31H34O2S2: C, 74.06; H, 6.82. Found: C, 73.82; H, 6.87.
S-Ethyl (4Z,6Z)-6-(Benzeneselenenyl)-5-(benzenesulfenyl)-3-ethoxy-7-
phenylhepta-4,6-dienoate (28) 45%, IR (film, cmϪ1) n 1680 (CO); 1H-
NMR (500 MHz, CDCl3) d: 1.03 (3H, t, Jϭ7 Hz, Me), 1.23 (3H, t, Jϭ7 Hz,
Me), 2.31 (1H, dd, Jϭ4, 15 Hz, 2-H), 2.65 (1H, dd, Jϭ9, 15 Hz, 2-H), 2.86
(2H, q, Jϭ7 Hz, CH2), 3.06—3.17 (2H, m, OCH2), 4.88—4.93 (1H, m, 3-
H), 6.26 (1H, d, Jϭ9 Hz, 4-H), 7.18—7.39 (16H, m, olefinic and ArH); 13C-
NMR (125 MHz, CDCl3) d: 14.63 (q), 15.15 (q), 23.34 (t), 49.11 (t), 64.26
(t), 73.73 (d), 127.07 (d), 127.43 (d), 127.77 (d), 127.85 (dϫ2), 128.66
(dϫ2), 128.78 (dϫ2), 129.15 (dϫ2), 129.87 (s), 131.46 (dϫ2), 133.09 (s),
133.96 (dϫ2), 136.91 (s), 137.81 (d), 138.48 (s), 139.62 (d), 196.01 (s); MS
m/z 493 (MϩϪEtS). Anal. Calcd for C29H30O2S2Se: C, 62.91; H, 5.46.
Found: C, 62.85; H, 5.48.
Intramolecular Cyclization of Penta-2,4-dienals (Typical Procedure)
A CH2Cl2 (2 ml) solution of 14a (50 mg, 0.14 mmol) and p-toluenesulfonic
acid (2.7 mg, 0.01 mmol) was stirred for 30 min at room temperature. The
reaction mixture was poured into a sat. NaHCO3 (50 ml). The work-up pro-
cedure and the purification by preparative TLC on silica gel eluting with
AcOEt–n-hexane (1 : 20) gave 3,4-bis(benezenesulfenyl)-2-t-butyl-2-cyclo-
pentenone (22a) (10 mg, 20%) as a yellow oil.
Acknoledgement This work was supported by a Grant-in-Aid for Sci-
entific Research (Nos. 14572000) from the Ministry of Education, Science,
Sports, and Culture of Japan.
1
22a: IR (film, cmϪ1) n 1670 (CO); H-NMR (500 MHz, CDCl3) d: 1.26
References
(9H, s, Meϫ3), 2.48 (1H, d, Jϭ19 Hz, 5-H), 2.64 (1H, dd, Jϭ7, 19 Hz, 5-H),
3.76 (1H, d, Jϭ7 Hz, 4-H), 7.19—7.22 (5H, m, ArH), 7.38—7.44 (3H, m,
ArH), 7.68—7.70 (2H, m, ArH); 13C-NMR (125 MHz, CDCl3) d: 29.21
(qϫ3), 34.30 (s), 44.05 (t), 47.02 (d), 128.70 (d), 128.86 (dϫ2), 129.11
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