A New 1-Alkoxy-2-(chalcogeno)allylic or 1-Alkoxy-2,4-bis(chalcogeno)penta-2,4-dienyl Cation: Highly-Regioselective Allylating or Penta-2,4-dienylating Electrophiles and Their Reactions

Article abstract of DOI:10.1021/jo9807767

2-(Chalcogeno)-1-ethoxyallylic cations 4A are easily generated from the reactions of 2-(chalcogeno)- 1-ethoxyprop-l-en-3-ols 2a-e or 2-(chalcogeno)prop-2-enal acetals 3a-c and TMSOTf and reacted with various nucleophiles to give the adducts 5a-8a, 5b-11b, and 5c-e regio and stereoselectively. 2,4-Bis(chalcogeno)penta-2,4-dienal acetals 16a,c and the 2,4,6-tris(phenylthio)hepta-2,4,6-trienal acetal 20c also gave the dienones 17a,c and 21c in good yields. Furthermore, the intramolecular cyclization of the alkenyl alcohols 25a,b and the 2,4-dienal 2,4-dinitrophenyl hydrazones 29a - c afforded the tetrahydrofurans 26a,b and 3,5-bis(chalcogeno)pyridines 30a-c, respectively.

Full text of DOI:10.1021/jo9807767

J . Org. Chem. 1998, 63, 6619-6624
6619
A New 1-Alk oxy-2-(ch a lcogen o)a llylic or
1-Alk oxy-2,4-bis(ch a lcogen o)p en ta -2,4-d ien yl Ca tion :
High ly-Regioselective Allyla tin g or P en ta -2,4-d ien yla tin g
Electr op h iles a n d Th eir Rea ction s
Mitsuhiro Yoshimatsu,* Satoshi Gotoh, Kazunari Ikeda, and Motonori Komori
Department of Chemistry, Faculty of Education, Gifu University, Yanagido, Gifu 501-11, J apan
Received April 24, 1998
2-(Chalcogeno)-1-ethoxyallylic cations 4A are easily generated from the reactions of 2-(chalcogeno)-
1-ethoxyprop-1-en-3-ols 2a -e or 2-(chalcogeno)prop-2-enal acetals 3a -c and TMSOTf and reacted
with various nucleophiles to give the adducts 5a -8a , 5b-11b, and 5c-e regio and stereoselectively.
2,4-Bis(chalcogeno)penta-2,4-dienal acetals 16a ,c and the 2,4,6-tris(phenylthio)hepta-2,4,6-trienal
acetal 20c also gave the dienones 17a ,c and 21c in good yields. Furthermore, the intramolecular
cyclization of the alkenyl alcohols 25a ,b and the 2,4-dienal 2,4-dinitrophenyl hydrazones 29a -c
afforded the tetrahydrofurans 26a ,b and 3,5-bis(chalcogeno)pyridines 30a -c, respectively.
Much attention has been paid to â-heteroatom-substi-
tuted allylic cations from both the synthetic and mecha-
nistic points of view. In particular, â-oxyallylic cations
are among the most practical of the allylic cations and
are used for cycloaddition with alkenes or conjugate
dienes, providing an important route to five- or seven-
membered ring systems.1 On the other hand, â-sulfur-2
or â-selenium-stabilized allylic cations were investigated
using the propenal diselenoacetals,3 2-selenopropenyl
bromide, or the corresponding alcohols;4 however, the
regio- and stereoselectivities of their electrophilic addition
reactions were not satisfactory. Furthermore, the prod-
uct allylic selenides were obtained as a mixture of the
[1,3] sigmatropic isomers.5 It is very difficult to control
the regioselectivity because it depends on the electrophi-
licity of the allylic cations and the substituent (R- and
â-postion) on the electrophile. To control the regioselec-
tivity, we planned to introduce an alkoxy group at the
1-position of the 2-chalcogene (2-sulfur or 2-selenium)-
substituted allylic cations. Although 2-(chalcogeno)allylic
cations are reported to be important for the contribution
of the cyclic intermediate 4B,4a high regioselectivities in
the nucleophilic substitution reactions of 1-alkoxy-2-
(chalcogeno) allylic cations 4A would be expected for the
reason that the reactivity of the R-alkoxy carbenium ion
is higher than that of the sulfur or selenium analogue.6
We selected the 1-ethoxy-2-(chalcogeno)prop-1-en-3-ols 2
and the 2-(chalcogeno)prop-2-enal acetals 3 as precursors
for the allylic cations 4A. Since the acid-promoted
reactions of 1-alkoxy-2-(chalcogene)-substituted allylic
cations with soft nucleophiles have not been reported,
herein we wish to report their reactions with various
nucleophiles and their application to the 2,4-bis(chalco-
geno)penta-2,4-dienylation reactions.
The allylic alcohols 2 and prop-2-enal O,O-acetals 3
were prepared by our original method as shown in
Scheme 1.7 2-Ethoxy-1-(phenylchalcogeno)ethenes 1 were
treated with BuLi at -70 °C, and successive treatment
with the corresponding aldehydes or ketones gave the
allylic alcohols 2. The reactions of the alcohols with CH-
(OEt)3/p-toluenesulfonic acid (TsOH) afforded the acetals
3 in high yields.
First, we examined the acid-promoted allylation of 4A
from 1-ethoxy-2-(seleno)prop-1-en-3-ols 2 in the presence
of O-trimethylsilyl trifluoromethanesulfonate (TMSOTf),
and the results are shown in Table 1. The reaction of
1-ethoxy-4,4-dimethyl-2-(phenylseleno)prop-1-en-3-ol (2a )
and allyltrimethylsilane at -78 °C afforded (Z)-4-ethoxy-
7,7-dimethyl-5-(phenylseleno)octa-1,4-diene (5a ) (entry
1). From observation of the 1H NMR spectral data, which
shows a ddd (J ) 1, 4, 7 Hz) at δ 3.54 due to the R-proton
of the ethoxy group and a doublet at δ 6.39 (J ) 1 Hz)
due to the olefinic proton, it was found that allylation
occurred at the R-position of the ethoxy group. The
stereochemistry of 5a was determined as Z by the NOE
experiment. Irradiation of the olefinic proton at δ 6.39
ppm increased the intensity of the methine proton at δ
3.54 ppm. Phenyl-2b and phenylethynyl-substituted
prop-1-en-3-ol 2e also gave the 1,4-diene 5b and 5e in
good yields (entries 2 and 5); however, 5d (R1 ) R2
)
Me) was obtained in low yield (entry 4). The correspond-
ing sulfur analogue 2c regioselectively gave the adduct
5c (entry 3).
Next, we examined the reactions of 2-(seleno)prop-2-
enal diethyl acetals 3a -c with various soft nucleophiles,
and the results are shown in Table 2. The reaction of
3a with allyltrimethylsilane in the presence of TMSOTf
gave (Z)-4-ethoxy-5-(phenylseleno)octa-1,5-diene (5a ) in
80% yield (Table 2, entry 1). The reaction of 3a with the
(1) (a) Hoffmann, H. M. R. Angew. Chem., Int. Ed. Engl. 1973, 12,
819. (b) Noyori, R. Acc. Chem. Res. 1979, 12, 61. (c) Chan, T. H. Acc.
Chem. Res. 1977, 10, 442. (d) Chan, T. H.; Ony, B. S. Tetrahedron 1980,
36, 2269. (e) Masuya, K.; Domon, K.; Tanino, K.; Kuwajima, I. J . Am.
Chem. Soc. 1998, 120, 1724 and references therein.
(2) Hunter, R.; Michael, J . P.; Walter, D. S. Tetrahedron Lett. 1992,
33, 5413. Hunter, R.; Michael, J . P.; Walter, D. S. Tetrahedron Lett.
1994, 35, 5481.
(3) Renard, M.; Hevesi, L. Tetrahedron Lett. 1983, 24, 3911.
(4) (a) Halazy, S.; Hevesi, L. J . Org. Chem. 1983, 48, 5242. (b)
Hevesi, L.; Renard, M.; Proess, G. J . Chem. Soc., Chem. Commun.
1986, 1725. (c) Renard, M.; Hevesi, L. J . Chem. Soc., Chem. Commun.
1986, 688.
(5) Hevesi, L.; Lavoix, A. Tetrahedron Lett. 1989, 30, 4433.
(6) Hevesi, L. Phosphorous, Sulfur, Silicon 1992, 67, 155.
(7) Yoshimatsu, M.; Oguri, K.; Gotoh, S.; Ikeda, K. J . Org. Chem.
1998, 63, 4475.
S0022-3263(98)00776-2 CCC: $15.00 © 1998 American Chemical Society
Published on Web 08/28/1998

6620 J . Org. Chem., Vol. 63, No. 19, 1998
Yoshimatsu et al.
Sch em e 1a
Sch em e 2
a
Reagents: (i) nBuLi/-70 °C/RCHO; (ii) CH(OEt)3/cat. TsOH.
Ta ble 1. Rea ction of
3-Eth oxy-2-(p h en ylselen o)-2-p r op en -1-ol w ith
Allyltr im eth ylsila n e
ylsilane also regioselectively afforded the same type of
product (5b) as that of the t-Bu analogue 3a (Table 2,
entry 5). The silyl enol ether and triethylaluminum gave
the addition products 6b and 7b, respectively (Table 2,
entries 6 and 7). The reaction of 3b with (trimethylsilyl)-
nitrile (TMSCN) gave the R-ethoxyallyl cyanide 8b in
good yield; however, vinyltrimethylsilane gave not the
addition products, but (Z)-3-phenyl-2-(phenylseleno)prop-
2-enal 9b predominantly (Table 2, entries 8 and 9).
Although the γ-(chalcogeno)prop-2-ynyl cations reacted
with the alkynyldiethylaluminum, the products were
obtained in low yield and accompanied with an ethylated
product.8 The prop-2-enal diethyl acetal 3b was reacted
with alkynyl nucleophlies to give the alkynylated prod-
ucts 10b and 11b as sole products, respectively (Table
2, entries 10 and 11). Sulfur analogue 3c gave the
product 5c in high yield (Table 2, entry 12). Plausible
mechanisms for formations of the products are shown in
Scheme 2. The treatment of the allylic alcohol 2 with
TMSOTf provides an allylic cation 4C, which easily
isomerizes to the more stable 4A and 4B. The reaction
of the nucleophile affords the adduct 5; however, the
hydrolysis of 4A,B gives the aldehyde 9b via a hemiacetal
13. We could not detect the adduct 12 through the direct
attack of the nucleophile to the intermediate 4C in the
reaction of the alcohol 2 or the acetal 3.
product
entry
alcohol 2
(% yield)
1
2
3
4
5
2a (R1 ) t-Bu; R2 ) H; Y ) Se)
2b (R1 ) Ph; R2 ) H; Y ) Se)
2c (R1 ) t-Bu; R2 ) H; Y ) Se)
2d (R1 ) R2 ) Me; Y ) Se)
5a (71)
5b (60)
5c (69)
5d (30)
5e (52)
2e (R1 ) phenylethynyl; R2 ) H; Y ) Se)
Ta ble 2. Rea ction of 2-(Ch a lcogen o)p r op -2-en a l Aceta ls
w ith Soft Nu cleop h iles
Furthermore, we performed the acid-promoted nucleo-
philic substitution reaction of 2,4-bis(chalcogeno)penta-
2,4-dienal acetals or 2,4,6-tris(chalcogeno)hepta-2,4,6-
trienal acetal. Penta-2,4-dienal acetals 16a ,c were
prepared from the tandem addition of PhYCHdCHOEt/
BuLi to the prop-2-enals 14a ,c and the successive treat-
ment with CH(OEt)3/TsOH. Trienal acetal 20c was also
obtained by the same route. Since the reaction of dienal
acetals 16a ,c with the nucleophiles using TMSOTf gave
the aldehyde 18c, not the adduct, we examined the
reaction using other Lewis acids. Lanthanide metals
were found to be a very suitable Lewis acid for these
addition reactions. The dienal acetal 16a (Y ) Se)
reacted with the silyl enol ether in the presence of Yb-
(OTf)3 to give the R-adduct of the alkoxide 17a in
moderate yield. The structure of the dienone 17a was
determined by the IR, 1H and 13C NMR, and mass
spectral data. The IR spectrum showed the absorption
trimethylsilyl enol ether gave the allylated ketone 6a in
high yield (Table 2, entry 2). S-Ethyl O-trimethylsilyl
ketene acetal afforded the thio ester 7a (Table 2, entry
3). We also examined the addition reaction of the
heteroatom nucleophile using i-Bu2AlSePh. Treatment
of 3a with 2 equiv of i-Bu2AlSePh/TMSOTf gave the O,-
Se-acetal 8a in 47% yield (Table 2, entry 4).
of the carbonyl group at ν 1690 cm-1
.
The 1H NMR
spectrum exhibits two singlets at δ 5.94 (brs) and 6.64
(brs) ppm due to the characteristic olefinic protons. Mass
The reactions of the 3-phenylallylic cation generated
from the acetal 3b were then examined. Allyltrimeth-
(8) Yoshimatsu, M.; Shimizu, H.; Kataoka, T. J . Chem. Soc., Chem.
Commun. 1995, 149.

Allylating or Penta-2,4-dienylating Electrophiles
J . Org. Chem., Vol. 63, No. 19, 1998 6621
Sch em e 3a
F igu r e 1.
the reduction of the 4-(phenylseleno)pent-4-enone (Scheme
5), were carried out. First, the pent-1-en-5-ol 25a was
oxidized by m-chloroperbenzoic acid (m-CPBA), and the
successive treatment of t-BuOK/THF/18-crown-6 gave
2-(benzylidene)-3-ethoxy-5-phenyltetrahydrofuran (26a )
in 68% yield as the sole product. The anti alcohol 25b
afforded the cis-substituted tetrahydrofuran 26b (77%)
predominantly. Structure assignment of 26a was per-
formed by 1H NMR spectral data, which exhibited a
characteristic olefinic proton at δ 5.48 (brs) and a pair of
doublets at δ 5.71 (J ) 5, 10 Hz) due to 5-H and δ 4.43
(J ) 4, 5 Hz) due to 3-H, respectively. The trans-
configuration between the phenyl and ethoxy groups was
determined by reference to our previous report on the
chemical shift method of the 3,5-disubstituted tetrahy-
drofurans, which was supported by a single X-ray analy-
sis.9 The chemical shift difference of 4-methylene protons
for 3,5-syn-26b was observed to be larger at 0.24 ppm
than that for 3,5-anti-26a . The stereostructure of the
benzylidene part of 26a was determined as Z by NOE
experiments. Irradiation of the olefinic proton at δ 5.48
ppm increased the intensities of the methylene protons
of the ethoxy group (3%) and the 3-methine proton (3%),
respectively. This result shows that the intramolecular
cycloaddition reaction of vinylselenoxide and the alkoxide
would proceed with retention of the configuration of the
vinylselenoxide.10 In the syn isomer 25a , this cyclization
proceeds through the addition-elemination of the alkoxy
vinylselenoxide 27a , which provides a 3,5-trans-tetrahy-
drofuran exclusively, while the anti isomer 25b gives 3,5-
cis-tetrahydrofuran through the intermediate 27b (Fig-
ure 1).
a
Reagents: (i) TMSOTf/CH2Cl2; (ii) PhYCH)CHOEt/n-BuLi;
(iii) CH(OEt)3/TsOH/EtOH; (iv) Yb(OTf)3/CH2)C(OTMS)Ph.
spectra show the molecular formula (C31H34O2Se2) at m/z
598. The stereochemistry of 17a was determined by the
NOE experiments. Irradiation of the 5-olefinic proton
at δ 6.64 ppm increased the intensities of the 7-olefinic
proton (8%) at δ 5.94 ppm and that of the R-proton of
the alkoxide (6%) at δ 4.05 ppm. The reaction of the
trienal acetal 20c with the silyl enol ether proceeded
stereoselectively to give the nona-4,6,8-trienone 21c in
good yield. High regioselectivities of the addition reac-
tions are explained as shown in Scheme 4. 2,4-Bis-
(chalcogeno)pentadienyl cation 22A, which easily forms
from the reactions of 16a ,c and Yb(OTf)3, exclusively
affords the adducts 17a ,c because of the high reactivity
of the R-oxy carbenium ions (Scheme 4).6 The cation 22C
is a stable intermediate by the contribution to the cyclic
22D and 22E; however, the adduct 23 was not obtained
in the reactions of 16a ,c. An adduct such as 24 derived
from 22F or 22G also was not given.
Furthermore, we also examined the reactions of 2,4-
bis(chalcogeno)penta-2,4-dienal derivatives with a radical
species (Scheme 6). 2,4-Bis(seleno)pentadienal acetal
16a underwent deselenylation by the normal reduction
of Bu3SnH/2,2′-azobis(isobutyronitrile) (AIBN) to give the
dienal 28 in 81% yield; however, the reduction of penta-
dienal hydrazones gave complex mixtures. Further
investigation of the reduction of hydrazones revealed that
To demonstrate more useful utilization of the adducts,
the cyclization reactions of the 2-(phenylseleno)pent-1-
en-5-ols 25a and 25b, which were easily obtained from
Sch em e 4

6622 J . Org. Chem., Vol. 63, No. 19, 1998
Yoshimatsu et al.
Exp er im en ta l Section 9c
Sch em e 5a
NOE experiments were run on a Varian Inova-400 (400
MHz) spectrometer at the Center of Instrumentation of Gifu
University. The starting materials, (Z)-2-ethoxyvinyl phenyl
sulfide and the selenium analogue, were quantitatively pre-
pared according to our previous work.7 Purities of the products
were assessed by the elemental analysis; however, the com-
pounds, satisfactory elemental analysis of which could not be
achieved because of their labilities, were determined as the
almost pure form by 1H and 13C NMR and mass spectrometric
data.
a
Reagents: (i) m-CPBA; (ii) t-BuOK/THF/18-crown-6.
Syn th eses of 1-Eth oxy-2-(ch a lcogen o)p r op -1-en -3-ols
2a -e, 1-Eth oxy-2-(ch a lcogen o)p en ta -1,4-d ien -3-ol 15a ,c,
a n d Hep ta -1,4,6-tr ien -3-ol 19c. Typ ica l P r oced u r e. Un-
der an Ar atmosphere, BuLi (28.0 mL, 42.2 mmol) was added
to a THF (50 mL) solution of 2-ethoxyvinyl phenyl selenide
(8.00 g, 35.2 mmol). After the mixture was stirred for 5 min,
a THF (10 mL) solution of tert-butyl aldehyde (6.60 g, 70.4
mmol) was added dropwise to the mixture. The whole was
poured into water (150 mL), and the organic layer was
separated. The aqueous layer was extracted with ether. The
organic layer and the extracts were combined and dried over
MgSO4. The solvent was removed under reduced pressure,
and the residue was purified by column chromatography on
silica gel eluting with AcOEt/hexane (1:20). (Z)-1-Ethoxy-4,4-
dimethyl-2-(phenylseleno)pent-1-en-3-ol (2a ) (7.60 g, 69%) was
obtained as a yellow oil.
Sch em e 6a
1
2a : IR (film, cm-1) 3600-3400 (OH); H NMR δ 0.93 (9H,
s), 1.29 (3H, t, J ) 7 Hz), 2.59 (1H, brd, J ) 10 Hz), 3.92 (2H,
q, J ) 7 Hz), 4.32 (1H, brd, J ) 10 Hz), 6.76 (1H, s), 7.14-
7.27 (3H, m), 7.43-7.48 (2H, m); 13C NMR δ 15.37 (q), 26.30
(q × 3), 37.41 (s), 68.99 (t), 79.92 (d), 108.57 (s), 125.97 (d),
128.85 (d × 2), 129.08 (d × 2), 134.30 (s), 155.67 (d); MS m/z
314 (M+). Anal. Calcd for C15H22O2Se: C, 57.51; H, 7.08.
Found: C, 57.46; H, 7.09.
(1Z,4Z)-1-E t h oxy-6,6-d im et h yl-2,4-b is(p h en ylselen o)-
h ep ta -1,4-d ien -3-ol (15a ): IR (film, cm-1) 3600-3200 (OH);
1H NMR δ 1.08 (9H, s), 1.21 (3H, t, J ) 7 Hz), 2.69 (1H, d, J
) 8 Hz), 3.86-3.92 (2H, m), 5.12 (1H, d, J ) 8 Hz), 6.46 (1H,
s), 6.74 (1H, s), 7.15-7.19 (6H, m), 7.39-7.44 (4H, m); 13C
NMR δ 15.28 (q), 30.64 (q × 3), 33.82 (s), 69.05 (t), 73.05 (d),
109.32 (s), 125.98 (d), 126.12 (d), 128.60 (s), 128.88 (d × 2),
129.00 (d × 2), 129.31 (d × 2), 130.55 (d × 2), 132.47 (s), 133.27
(s), 147.68 (d), 156.51 (d); MS m/z 496 (M+). Anal. Calcd for
a
Reagents: (i) Bu3SnH/AIBN; (ii) AIBN/benzene/reflux.
the product is 3,5-bis(chalcogeno)pyridine 30 and AIBN
acts as an effective reagent for formation of the 3,5-bis-
(chalcogeno)pyridines. 2,4-Bis(phenylseleno)penta-2,4-
dienal hydrazones 29b (R ) Ph) gave the pyridine 30b
in good yield; however, the sulfur analogue 29c was
obtained in low yield. The cyclization of the penta-2,4-
dienal hydrazones would proceed in the 6-endo-mode via
the iminyl radical 32. Recently, the 5-exo-mode cycliza-
tion of the alkylidene iminyl radicals derived from the
O-carboxymethyl oximes has been reported.11 Our cy-
clization of the dienal hydrazones would proceed by the
same route, which is the hydride abstraction12 of 29 and
the following formation of the iminyl radical 32,13 and
finally, the iminyl radical 32 cyclizes in the 6-endo-mode.
Moreover, the vinyl-, dienyl-, and trienylchalcogenides
moiety can be converted into other functional groups;14
work is under way to clarify their fundamental reactivi-
ties, which are of potential interest. The results of our
further investigation will be reported elsewhere.
C
23H28O2Se2: C, 55.88; H, 5.71. Found: C, 55.74; H, 5.71.
(1Z,4Z)-1-Eth oxy-6,6-dim eth yl-2,4-bis(ph en ylth io)h epta-
1,4-d ien -3-ol (15c): IR (film, cm-1) 3600-3400 (OH); 1H NMR
δ 1.04 (9H, s), 1.17 (3H, t, J ) 7 Hz), 2.78 (1H, brd, J ) 8 Hz),
3.82-3.89 (2H, m), 5.08 (1H, brd, J ) 8 Hz), 6.39 (1H, s), 6.71
(1H, s), 7.06-7.11 (2H, m), 7.18-7.32 (8H, m); 13C NMR δ
15.10 (q), 30.27 (q × 3), 33.32 (s), 69.20 (t), 71.11 (d), 109.22
(s), 125.11 (d), 125.31 (d), 126.48 (d × 2), 127.73 (d × 2), 128.56
(d × 2), 128.64 (d × 2), 129.64 (s), 136.88 (s), 138.51 (s), 148.21
(d), 156.95 (d); high-resolution mass calcd for C23H28O2S2
400.1531, found m/z 400.1539.
(1Z,4Z,6Z)-1-E t h oxy-8,8-d im e t h yl-2,4,6-t r is(p h e n yl-
th io)n on a -1,4,6-tr ien -3-ol (19c): IR (film, cm-1) 3600-3400
(OH); 1H NMR δ 1.11 (3H, t, J ) 7 Hz), 1.20 (9H, s), 2.05 (1H,
brs), 3.79 (2H, q, J ) 7 Hz), 5.07 (1H, brs), 5.60 (1H, s), 6.51
(1H, s), 6.66 (1H, s), 7.07-7.27 (15H, m); 13C NMR δ 15.03
(q), 30.42 (q × 3), 34.07 (s), 69.22 (t), 69.56 (d), 109.12 (s),
125.15 (s), 125.59 (d), 125.63 (d), 126.05 (d), 126.82 (d × 2),
128.52 (d × 2), 128.61 (d × 2), 128.71 (d × 2), 129.34 (d × 2),
129.76 (d × 2), 135.27 (s), 135.30 (s), 135.48 (d), 136.18 (s),
138.18 (s), 152.84 (d), 156.61 (d); MS m/z 534 (M+). Anal. Calcd
for C31H34O2S3: C, 69.62; H, 6.41. Found: C, 69.10; H, 6.48.
Rea ction of P r op -1-en -3-ols 2a -e w ith th e Soft Nu -
cleop h iles. Typ ica l P r oced u r e. TMSOTf (0.29 mL, 1.50
mmol) was added dropwise to a CH2Cl2 (2 mL) solution of (Z)-
1-ethoxy-4,4-dimethylpent-1-en-3-ol (2a ) (0.16 g, 0.50 mmol)
and allyltrimethylsilane (0.29 g, 2.50 mmol) at -78 °C under
an Ar atmosphere. The reaction mixture was poured into a
saturated NaHCO3 solution (100 mL), and then the organic
layer was separated. The aqueous layer was extracted with
(9) (a) Williams, D. R.; Harigaya, Y.; Moore, J . L.; D’sa, A. J . Am.
Chem. Soc. 1984, 106, 2641. (b) Mihelich, E. D.; Hite, G. A. J . Am.
Chem. Soc. 1992, 114, 7318. (c) For general experimental procedures,
see: Yoshimatsu, M.; Naito, M.; Shimizu, H.; Muraoka, O.; Tanabe,
G.; Kataoka, T. J . Org. Chem. 1996, 61, 8200.
(10) Tiecco, M.; Chianelli, D.; Testaferri, L.; Bartoli, D. Tetrahedron
1986, 42, 4889.
(11) Boivin, J .; Fouquet, E.; Zard, S. Z. J . Am. Chem. Soc. 1991,
113, 1055. Boivin, J .; Fouquet, E.; Zard, S. Z. Tetrahedron Lett. 1991,
32, 4299.
(12) Griller, D.; Mendenhall, G. D.; Van-Hoff, W.; Ingold, K. U. J .
Am. Chem. Soc. 1974, 96, 6068. Symons, M. C. R. Tetrahedron 1973,
29, 615. Roberts, B. P.; Winter, J . N. J . Chem. Soc., Perkin Trans. 2,
1979, 1353.
(13) Boivin, J .; Schiano, A.-M.; Zard, S. Z. Tetrahedron Lett. 1992,
33, 7849.
(14) Comasseto, J . V.; Ling, L. W.; Petragnani, N.; Stefani, A.
Synthesis 1997, 373.

Allylating or Penta-2,4-dienylating Electrophiles
J . Org. Chem., Vol. 63, No. 19, 1998 6623
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 CH2-
Cl2-hexane (1:5).
(Z)-4-Ethoxy-7,7-dimethyl-5-(phenylseleno)oct-1,5-diene (5a )
(0.12 g, 71%) was obtained as a pale yellow oil. The stereo-
structure of 5a was determined as Z by the observation of the
NOE enhancement between the olefinic proton at δ 6.39 and
the methine proton at δ 3.54 (8%).
× 2), 130.36 (s), 131.59 (d × 2), 132.20 (d × 2), 135.90 (s),
146.61 (d), 197.08 (s); MS m/z 450 (M+ - OEt). Anal. Calcd
for C23H27BrO2Se: C, 55.88; H, 5.51. Found: C, 55.69; H, 5.48.
(Z)-3-Eth oxy-5-p h en yl-4-(p h en ylselen o)p en t-4-en op h e-
n on e (6b): a yellow oil; IR (film, cm-1) 1690 (CO), 1100
1
(ether); H NMR δ 1.05 (3H, t, J ) 7 Hz), 3.24-3.33 (3H, m),
3.54-3.60 (1H, m), 4.49-4.52 (1H, m), 7.16-7.53 (12H, m),
7.58-7.59 (2H, m), 7.85-7.87 (2H, m); 13C NMR δ 15.12 (q),
45.31 (t), 64.61 (t), 80.07 (d), 127.35 (d), 127.82 (s), 128.01 (d
× 2), 128.18 (d × 2), 128.42 (d × 2), 129.18 (d × 2), 129.31 (s),
129.37 (d × 2), 132.72 (d × 2), 132.86 (d), 133.41 (s), 133.91
(d), 136.42 (d), 137.16 (s), 197.70 (s); MS m/z 390 (M+ - EtOH).
Anal. Calcd for C25H24O2Se: C, 68.96; H, 5.56. Found: C,
68.79; H, 5.54.
5a : a pale yellow oil; IR (film, cm-1) 1090 (ether); 1H NMR
δ 1.04 (3H, t, J ) 7 Hz), 1.26 (9H, s), 2.22-2.29 (1H, m), 2.46-
2.53 (1H, m), 3.03-3.11 (1H, m), 3.40-3.56 (1H, m), 3.54 (1H,
ddd, J ) 1, 4, 7 Hz), 4.95-5.01 (2H, m), 5.71-5.78 (1H, m),
6.39 (1H, s), 7.23-7.25 (3H, m), 7.46-7.47 (2H, m); 13C NMR
δ 15.18 (q), 30.99 (q × 3), 33.74 (s), 40.29 (t), 63.88 (t), 83.33
(d), 116.25 (t), 126.89 (d), 129.01 (d × 2), 130.69 (s), 132.54 (d
× 2), 135.36 (d), 145.39 (d); MS m/z 338 (M+). Anal. Calcd
for C18H26OSe: C, 64.08; H, 7.77. Found: C, 63.85; H, 7.76.
Syn th eses of th e P r op -2-en a l Aceta ls 3a -c, P en ta -2,4-
d ien a l Aceta ls 16a ,c, a n d Hep ta -2,4,6-tr ien a l Aceta l 20c.
The experimental procedure was performed according to the
general method.
(Z)-4,4-Dim eth yl-2-(p h en ylselen o)p en t-2-en a l d ieth yl
a ceta l (3a ): a pale yellow oil; IR (film, cm-1) 1050, 1110
(acetals); 1H NMR δ 1.13 (6H, t, J ) 7 Hz), 1.26 (9H, s), 3.31-
3.39 (2H, m), 3.47-3.54 (2H, m), 4.58 (1H, s), 6.66 (1H, s),
7.20-7.26 (3H, m), 7.45-7.48 (2H, m); 13C NMR δ 15.06 (q ×
2), 30.67 (q × 3), 33.37 (s), 61.97 (t × 2), 103.38 (d), 125.48 (s),
126.54 (d), 128.86 (d × 2), 129.19 (s), 132.05 (d × 2), 147.92
(d); MS m/z 342 (M+). Anal. Calcd for C17H26O2Se: C, 59.82;
H, 7.68. Found: C, 59.42; H, 7.41.
(2Z,4Z)-6,6-Dim et h yl-2,4-b is(p h en ylselen o)h ep t a -2,4-
d ien a l d ieth yl a ceta l (16a ): IR (film, cm-1) 1120, 1050
(acetal); 1H NMR δ 0.97 (6H, t, J ) 7 Hz), 1.31 (9H, s), 2.85-
2.91 (2H, m), 3.15-3.21 (2H, m), 4.31 (1H, s), 6.06 (1H, s), 6.69
(1H, s), 7.21-7.31 (6H, m), 7.41-7.44 (2H, m), 7.52-7.54 (2H,
m); 13C NMR δ 14.94 (q × 2), 30.67 (q × 3), 34.48 (s), 61.95 (t
× 2), 101.08 (d), 124.97 (s), 126.97 (d), 127.59 (d), 128.70 (d ×
2), 128.74 (d × 2), 128.97 (s), 130.53 (s), 131.65 (s), 133.88 (d
× 2), 134.49 (d × 2), 135.69 (d), 149.06 (d); MS m/z 524 (M+).
Anal. Calcd for C25H32O2Se2: C, 57.47; H, 6.17. Found: C,
57.39; H, 6.17.
(2Z,4Z)-6,6-Dim et h yl-2,4-b is(p h en ylt h io)h ep t a -2,4-d i-
en a l d ieth yl a ceta l (16c): IR (film, cm-1) 1120, 1060 (acetal);
1H NMR δ 1.15 (6H, t, J ) 7 Hz), 1.27 (9H, s), 3.37-3.42 (2H,
m), 3.49-3.54 (2H, m), 4.58 (1H, s), 6.62 (1H, s), 7.14-7.27
(9H, m), 7.30-7.32 (2H, m). The EI mass spectrum of 16c
did not show the M+ (m/z 428) but showed many peaks because
of its lability. The elemental analysis also did not give
satisfactory results.
(4Z,6Z)-3-E t h oxy-8,8-d im et h yl-4,6-b is(p h en ylselen o)-
n on a -4,6-d ien op h en on e (17a ): IR (film, cm-1) 1690 (CO),
1
1040 (ether); H NMR δ 0.71 (3H, t, J ) 7 Hz), 1.35 (9H, s),
2.68 (2H, q, J ) 7 Hz), 2.93 (1H, dd, J ) 10, 16 Hz), 3.07 (1H,
dd, J ) 3, 16 Hz), 4.05 (1H, dd, J ) 2, 9 Hz), 5.94 (1H, s), 6.64
(1H, s), 7.22-7.41 (10H, m), 7.46-7.48 (1H, m), 7.55-7.57 (2H,
m), 7.71-7.74 (2H, m); 13C NMR δ 14.96 (q), 30.80 (q × 3),
34.46 (s), 45.79 (t), 64.02 (t), 77.34 (d), 125.93 (s), 127.17 (d),
127.99 (d), 128.15 (d × 2), 128.30 (d × 2), 128.63 (s), 128.83 (d
× 2), 129.07 (d × 2), 130.49 (s), 132.70 (d), 133.92 (d), 134.32
(d × 2), 134.42 (d × 2), 135.92 (s), 137.10 (s), 148.19 (d), 197.47
(s); MS m/z 598 (M+). Anal. Calcd for C31H34O2Se2: C, 62.42;
H, 5.75. Found: C, 62.01; H, 5.85. The stereostructure of 17a
was determined as 4Z,6Z by the observation of the NOE
enhancements as described above.
(4Z,6Z)-3-Eth oxy-8,8-dim eth yl-4,6-bis(ph en ylth io)n on a-
4,6-d ien op h en on e (17c): IR (film, cm-1) 1690 (CO), 1100
1
(ether); H NMR δ 1.01 (3H, t, J ) 7 Hz), 1.29 (9H, s), 3.12-
3.23 (2H, m), 3.34 (1H, dd, J ) 3, 16 Hz), 3.46-3.53 (1H, m),
4.18 (1H, dd, J ) 3, 9 Hz), 6.51 (1H, s), 7.14-7.39 (13H, m),
7.46-7.50 (1H, m), 7.85 (2H, d, J ) 8 Hz); 13C NMR δ 15.07
(q), 30.72 (q × 3), 33.40 (s), 45.68 (t), 64.22 (t), 78.56 (d), 126.25
(d × 2), 128.13 (d × 4), 128.30 (d × 4), 128.90 (d × 2), 129.26
(d × 2), 130.09 (s × 2), 132.71 (d), 135.23 (s), 137.13 (s × 2),
146.97 (d × 2), 198.06 (s); MS m/z 368 (M+ - (PhCO + Et)).
Anal. Calcd for C31H34O2S2: C, 74.06; H, 6.82. Found: C,
74.23; H, 7.67.
(4Z,6Z,8Z)-3-Eth oxy-10,10-d im eth yl-4,6,8-tr is(p h en yl-
th io)u n d eca -4,6,8-tr ien op h en on e (21c): IR (film, cm-1
)
1690 (CO), 1100 (ether); 1H NMR δ 0.73 (3H, t, J ) 7 Hz),
1.34 (9H, s), 2.73-2.78 (2H, m), 2.98 (1H, dd, J ) 9, 16 Hz),
3.12 (1H, dd, J ) 2, 16 Hz), 4.08 (1H, dd, J ) 2, 9 Hz), 6.02
(1H, s), 6.49 (1H, s), 7.20-7.30 (10H, m), 7.34-7.39 (8H, m),
7.47-7.50 (1H, m), 7.75-7.77 (2H, m); 13C NMR δ 14.95 (q),
30.67 (q × 3), 34.10 (s), 45.71 (t), 64.05 (t), 76.18 (d), 126.45
(d), 127.06 (s), 127.46 (d), 128.17 (d × 3), 128.34 (d × 3), 128.67
(d × 3), 128.97 (d × 3), 131.20 (d × 3), 131.59 (d × 3), 132.70
(d), 132.78 (d), 133.45 (s), 135.69 (s × 2), 136.41 (s × 2), 137.06
(s), 150.16 (d), 197.56 (s); EI MS m/z 502 ((M+ - (PhCO + Et)).
Anal. Calcd for C39H40O2S3: C, 73.55; H, 6.33. Found: C,
73.42; H, 6.28.
(2Z,4Z,6Z)-8,8-Dim eth yl-2,4,6-tr is(ph en ylth io)n on a-2,4,6-
tr ien a l d ieth yl a ceta l (20c): IR (film, cm-1) 1180-1000
(acetal); 1H NMR δ 0.91 (6H, t, J ) 7 Hz), 1.33 (9H, s), 2.83-
2.89 (2H, m), 3.07-3.13 (2H, m), 4.33 (1H, s), 6.03 (1H, s), 6.30
(1H, s), 6.44 (1H, s), 7.00-7.04 (1H, m), 7.13-7.28 (12H, m),
7.31-7.33 (2H, m); 13C NMR δ 14.89 (q × 2), 30.66 (q × 3),
34.28 (s), 61.61 (t × 2), 100.16 (d), 110.69 (s), 125.91 (d), 126.84
(d), 126.88 (d), 128.48 (d × 2), 128.52 (d × 2), 128.65 (d × 2),
130.03 (d × 2), 131.50 (d × 2), 131.69 (s), 131.92 (d × 2), 132.19
(d), 133.76 (s), 133.86 (s), 134.82 (s), 135.93 (s), 137.32 (d),
152.00 (d); MS m/z 517 (M+ - OEt). Anal. Calcd for
Syn th eses of th e P r op -2-en a l 14a ,c a n d P en ta -2,4-
d ien a l 18c. Typ ica l P r oced u r e.7 TMSOTf (4.70 mL, 24.3
mmol) was added dropwise to a CH2Cl2 (80 mL) solution of
(Z)-1-ethoxy-4,4-dimethyl-2-(phenylseleno)pent-1-en-3-ol (2a )
(7.60 g, 24.3 mmol) at -78 °C under an Ar atmosphere. After
being stirred for 10 min, the reaction mixture was poured into
a saturated NaHCO3 (150 mL) solution. The workup proce-
dure afforded (Z)-4,4-dimethyl-2-(phenylseleno)pent-2-enal (14a)
(6.34 g, 98%) as a yellow oil.
C
33H38O2S3: C, 70.42; H, 6.81. Found: C, 70.18; H, 6.85.
Rea ction s of P r op -2-en a l Aceta ls 3a -c, P en ta -2,4-
d ien a l Aceta ls 16a ,c, a n d Hep ta -2,4,6-tr ien a l Aceta l 20c
w ith Soft Nu cleop h iles. The experiments were performed
by the same procedure as described above for the reaction of
2a with allyltrimethylsilane.
14a : IR (film, cm-1) 1680 (CO); 1H NMR δ 1.37 (9H, s),
7.20-7.24 (3H, m), 7.35-7.38 (2H, m), 7.36 (1H, s), 9.23 (1H,
s); 13C NMR δ 29.96 (q × 3), 35.35 (s), 126.92 (d), 129.18 (d ×
2), 131.05 (s), 131.43 (d × 2), 132.49 (s), 170.02 (d), 191.64 (d);
MS m/z 268 (M+). Anal. Calcd for C13H16OSe: C, 58.43; H,
6.04. Found: C, 58.34; H, 6.01.
Syn th eses of syn - a n d a n ti-P en t-4-en -1-ols 25a ,b. The
reduction of 6b was performed according to our previous
paper.9c
(Z)-4′-Br om o-3-eth oxy-6,6-d im eth yl-4-(p h en ylselen o)-
h ep t-4-en op h en on e (6a ): a yellow oil; IR (film, cm-1) 1690
(CO), 1110 (ether); 1H NMR δ 0.96 (3H, t, J ) 7 Hz), 1.29 (9H,
s), 3.06-3.13 (2H, m), 3.28 (1H, dd, J ) 3, 7 Hz), 3.43 (1H, dd,
J ) 7, 9 Hz), 4.18 (1H, dd, J ) 3, 9 Hz), 6.55 (1H, s), 7.22-
7.26 (3H, m), 7.44-7.55 (4H, m), 7.57-7.69 (2H, m); 13C NMR
δ 14.99 (q), 30.93 (q × 3), 33.78 (s), 45.62 (t), 64.06 (t), 80.23
(d), 127.03 (d), 127.83 (s), 128.29 (s), 129.14 (d × 2), 129.72 (d
(1R*,3R*)-(Z)-3-Eth oxy-1,5-d ip h en yl-4-(p h en ylselen o)-
p en t-4-en -1-ol (25a ): IR (film, cm-1) 3700-3150 (OH), 1050

6624 J . Org. Chem., Vol. 63, No. 19, 1998
Yoshimatsu et al.
1
(ether); H NMR δ 1.15 (3H, t, J ) 7 Hz), 2.15-2.28 (2H, m),
dimethylhepta-2,4-dienal (28) (31 mg, 81%) and (PhSe)2 (73
mg, 84%). The structure of 28 was determined by comparison
with the literature data.15
3.06-3.13 (1H, m), 3.53-3.61 (1H, m), 3.61 (1H, d, J ) 5 Hz),
3.94 (1H, dd, J ) 3, 8 Hz), 4.98 (1H, s), 7.11-7.35 (14H, m),
7.53 (2H, d, J ) 7 Hz); 13C NMR δ 15.34 (q), 43.49 (t), 64.41
(t), 71.21 (d), 80.96 (d), 125.39 (d × 2), 126.83 (d), 127.54 (d),
127.67 (d), 127.98 (d × 2), 128.21 (d × 2), 128.71 (s), 129.05 (d
× 2), 129.31 (d × 2), 132.16 (d), 133.34 (s), 133.64 (d × 2),
136.53 (s), 144.32 (s); high-resolution mass calcd for C25H26O2-
Se 438.1118, found m/z 438.1083.
(2E,4E)-6,6-Dim eth ylh ep ta -2,4-d ien a l (28): 1H NMR δ
1.10 (9H, s), 6.11 (1H, dd, J ) 8, 15 Hz), 6.25 (1H, ddd, J ) 1,
9, 15 Hz), 6.30 (1H, dd, J ) 1, 15 Hz), 7.08 (1H, ddd, J ) 1, 9,
15 Hz), 9.53 (1H, d, J ) 8 Hz).
Syn th eses of P en ta -2,4-d ien a l 2,4-Din itr op h en ylh y-
d r a zon es 29a -c. Typ ica l P r oced u r e. A benzene (30 mL)
solution of (2Z,4Z)- and (2E,4Z)-6,6-dimethyl-2,4-bis(phenylse-
leno)hepta-2,4-dienal (1.00 g, 2.23 mmol), 2,4-dinitrophenyl-
hydrazine (0.88 g, 4.46 mmol), and TsOH (40 mg, 0.20 mmol)
was refluxed for 0.25 h. The solvent was removed under
reduced pressure. The residue was purified by column chro-
matography on silica gel, eluting with AcOEt-hexane (1:10)
to afford (2Z,4Z)- and (2E,4Z)-6,6-dimethyl-2,4-bis(phenylse-
leno)hepta-2,4-dien-al 2,4-dinitrophenyl hydrazone (29a ) (1.38
g, quant) as orange prisms (mp 131-133 °C).
(1S*,3R*)-(Z)-3-Eth oxy-1,5-d ip h en yl-4-(p h en ylselen o)-
p en t-4-en -1-ol (25b): IR (film, cm-1) 3700-3200 (OH), 1040
1
(ether); H NMR δ1.17 (3H, t, J ) 7 Hz), 1.96-2.04 (1H, m),
2.12-2.23 (1H, m), 3.18-3.25 (1H, m), 3.62-3.70 (1H, m), 4.00
(1H, dd, J ) 3, 10 Hz), 4.06 (1H, s), 4.70 (1H, dd, J ) 3, 9 Hz),
7.17-7.33 (12H, m), 7.41 (2H, dd, J ) 2, 7 Hz), 7.50 (2H, d, J
) 7 Hz); high-resolution mass calcd for C25H26O2Se 438.1089,
found m/z 438.1110.
Cycliza tion Rea ction s of P en t-5-en -1-ols 25a ,b by m -
CP BA/t-Bu OK. Typ ica l P r oced u r e. m-CPBA (0.10 g, 0.46
mmol) was added to a ClCH2CH2Cl (30 mL) solution of syn
alcohol 25a (0.20 g, 0.46 mmol) at 0 °C. After 10 min of
stirring, the mixture was washed with saturated NaHCO3
solution (100 × 3 mL). The organic layer was dried over
MgSO4. The solvent was removed under reduced pressure.
The almost pure selenoxide thus obtained was used without
further purification because of its lability. A THF (2 mL)
solution of the residue was added dropwise to a THF (3 mL)
solution of t-BuOK (0.08 g, 0.72 mmol) and 18-crown-6 (10 mg,
0.04 mmol) at -78 °C under an Ar atmosphere. After 10 min
of stirring, the mixture was poured into water (100 mL). The
organic layer was separated, and the aqueous layer was
extracted with ether. The organic layer and the extracts were
combined and dried over MgSO4. The solvent was removed
under reduced pressure. The residue was purified by prepara-
tive TLC on silica gel, eluting with AcOEt-hexane (1:30) to
give (3R*,5S*)-(Z)-2-(benzylidene)-3-ethoxy-5-phenyltetrahy-
drofuran (26) (0.09 g, 68%) as a colorless oil. The stereostruc-
ture of the 2-benzylidene group of 26a was determined as Z
by the observation of NOE enhancement as described above.
29a : IR (film, cm-1) 1510, 1340, 850 (NO2); 1H NMR δ 1.15
(s), 1.38 (s), 6.15 (d, J ) 1 Hz), 6.25 (d, J ) 1 Hz), 6.83 (brs),
6.85 (brs), 6.96-6.97 (m), 7.13-7.41 (m), 7.50-7.52 (m), 8.00
(dd, J ) 2, 10 Hz), 8.04 (dd, J ) 2, 10 Hz), 8.97 (d, J ) 3 Hz),
9.00 (d, J ) 2 Hz), 10.86 (s), 10.97 (s); 13C NMR δ 30.12 (2E-
q), 30.70 (2Z-q), 35.07 (2Z-s), 36.23 (2E-s), 116.78 (2Z-d), 116.90
(2E-d), 122.48 (2E-s), 123.04 (d), 124.61 (2Z-s), 126.90 (d),
127.04 (d), 127.27 (d), 127.45 (d), 128.45 (s), 128.76 (d), 128.93
(d), 129.06 (d), 129.12 (d), 129.16 (d), 129.22 (d), 129.25 (d),
129.42 (d), 129.51 (d), 130.34 (s), 133.09 (d), 133.26 (d), 133.63
(d), 138.22 (2Z-s), 138.24 (2E-s), 143.87 (2E-s), 144.33 (2Z-s),
144.40 (d), 147.36 (2Z-d), 148.06 (2E-d), 151.94 (2E-d), 153.07
(2Z-d); MS m/z 447 (M+ - NH-2,4-dinitrophenyl). Anal. Calcd
for C27H26N4O2Se2: C, 51.68; H, 4.17; N, 8.92. Found: C,
51.61; H, 4.21; N, 8.98.
Rea ction s of P en ta -2,4-d ien a l 2,4-Din itr op h en ylh y-
d r a zon es 29a -c w ith AIBN. Typ ica l P r oced u r e.
A
benzene (2 mL) solution of AIBN (0.08 g, 0.50 mmol) and
penta-2,4-dienal 2,4-dinitrophenyl hydrazone (29a ) (0.10 g,
0.16 mmol) was refluxed for 0.5 h under an Ar atmosphere.
The solvent was removed under reduced pressure. The residue
was purified by preparative TLC on silica gel, eluting with
AcOEt-hexane (1:20) to afford 2-tert-butyl-3,5-bis(phenylse-
leno)pyridine (30a ) (0.04 g, 47%) as a colorless oil.
26a : IR (film, cm-1) 1120 (ether); H NMR δ 1.26 (3H, t, J
1
) 7 Hz), 2.00-2.06 (1H, m), 2.73-2.78 (1H, m), 3.59-3.69 (2H,
m), 4.68-4.72 (1H, m), 5.40 (1H, dd, J ) 6, 9 Hz), 5.51 (1H,
s), 7.09-7.13 (1H, m), 7.25-7.45 (7H, m), 7.62-7.64 (2H, m);
13C NMR δ 15.45 (q), 39.70 (t), 65.01 (t), 79.55 (d), 81.93 (d),
98.94 (d), 125.25 (d), 125.85 (d × 2), 127.82 (d × 2), 128.00
(d), 128.19 (d × 2), 128.52 (d × 2), 136.22 (s), 141.06 (s), 155.82
(s); high-resolution mass calcd for C19H20O2 280.1474, found
m/z 280.1459.
30a : IR (film, cm-1) 3050, 1570, 1470, 1420, 1360, 1140,
1030, 1020, 770, 730; 1H NMR δ 1.53 (9H, s), 7.17-7.39 (10H,
m), 7.51 (1H, brd, J ) 2 Hz), 8.36 (1H, brd, J ) 2 Hz); 13C
NMR δ 29.51 (q × 3), 39.73 (s), 126.28 (s), 127.84 (d), 128.20
(d), 128.96 (s), 129.12 (s), 129.45 (d × 2), 129.71 (d × 2), 130.79
(s), 133.64 (d × 2), 134.35 (d × 2), 145.56 (d), 148.18 (d), 165.26
(s); EI-MS m/z 370 (M+ - Ph); FAB-high-resolution mass calcd
for C21H21NSe 448.0090, found m/z 448.0076.
(3R*,5R*)-(Z)-2-(Ben zylid en e)-3-et h oxy-5-p h en ylt et -
r a h yd r ofu r a n (26b): IR (film, cm-1) 1090 (ether); H NMR
1
δ 1.27 (3H, t, J ) 7 Hz), 2.05 (1H, ddd, J ) 3, 5, 13 Hz), 2.51
(1H, dd, J ) 5, 13 Hz), 3.49-3.53 (1H, m), 3.76-3.82 (1H, m),
4.44 (1H, d, J ) 4 Hz), 5.48 (1H, s), 5.71 (1H, dd, J ) 5, 10
Hz), 7.12-7.16 (1H, m), 7.25-7.42 (7H, m), 7.63-7.67 (2H,
m); 13C NMR δ 15.28 (q), 41.42 (t), 63.81 (t), 80.78 (d), 83.73
(d), 101.53 (d), 125.61 (d), 125.68 (d × 2), 127.97 (d), 128.00 (d
× 2), 128.28 (d × 2), 128.59 (d × 2), 135.99 (s), 141.04 (s),
155.51 (s); high-resolution mass calcd for C19H20O2 280.1450,
found m/z 280.1469.
Rea ction of P en ta -2,4-d ien a l Aceta l 16a w ith Bu 3Sn H/
AIBN. A benzene (2 mL) solution of penta-2,4-dienal acetal
16a (0.15 g, 0.28 mmol), tributyltin hydride (0.26 g, 0.86
mmol), and AIBN (10 mg) was refluxed for 0.3 h under an Ar
atmosphere. The solvent was removed under reduced pres-
sure. The residue was purified by preparative TLC on silica
gel eluting with CH2Cl2-hexane (1:5), to afford (2E,4E)-6,6-
Ack n ow led gm en t. The support of a part of this
work by the Ministry of Education, Science and Culture,
J apan, is gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Characterization
data for the products 2b-e, 3b,c, 5b-e, 7a ,b, 8a ,b, 9b-11b,
14c, 18c, 29b,c, and 30b,c and NMR spectra, complete with
peak assignments of other products (34 pages). This material
is contained in libraries on microfiche, immediately follows this
article in the microfilm version of the journal, and can be
ordered from the ACS; see any current masthead page for
ordering information.
J O9807767
(15) Stuetz, A.; Granitzer, W.; Roth, S. Tetrahedron 1985, 41, 5685.