Stereoseleetive Syntheses of β,γ-Unsaturated Esters and γ-Lactones: 1-(Benzotriazol-1-yl)-3-(diphenylphosphoryl)-1-ethoxy-1-propene, a Protected =CCH2CO2Et Synthon Equivalent

Article abstract of DOI:10.1021/jo9701647

l-(Benzotriazol-l-yl)-3-(diphenylphosphoryl)-l-ethoxy-l-propene (3), prepared from N-(α-ethoxyallyl)benzotriazole (1), underwent selective Horner reactions with aldehydes to give substituted dienes. Subsequent hydrolysis of these intermediates readily produced β,γ-unsaturated esters 2a-c in good yields. Similar reactions with ketones followed by hydrolysis of 10 produced, depending on the conditions, either the corresponding γ,γ-disubstituted β,γ-unsaturated esters 11a-d or γ-lactones 9a-c and 13. A double lithiation process provided β,γ,γ-trisubstituted β,γ-unsaturated esters 15, 18, and β,γ,γ-trisubstituted γ-lactone 14.

Full text of DOI:10.1021/jo9701647

J . Org. Chem. 1997, 62, 4131-4136
4131
Ster eoselective Syn th eses of â,γ-Un sa tu r a ted
Ester s a n d γ-La cton es:
1-(Ben zotr ia zol-1-yl)-3-(d ip h en ylp h osp h or yl)-1-eth oxy-1-p r op en e, a
P r otected dCCH2CO2Et Syn th on Equ iva len t
Alan R. Katritzky,* Daming Feng, and Hengyuan Lang
Center for Heterocyclic Compounds, Department of Chemistry, University of Florida,
Gainesville, Florida 32611-7200
Received J anuary 29, 1997X
1-(Benzotriazol-1-yl)-3-(diphenylphosphoryl)-1-ethoxy-1-propene (3), prepared from N-(R-ethoxy-
allyl)benzotriazole (1), underwent selective Horner reactions with aldehydes to give substituted
dienes. Subsequent hydrolysis of these intermediates readily produced â,γ-unsaturated esters 2a -c
in good yields. Similar reactions with ketones followed by hydrolysis of 10 produced, depending
on the conditions, either the corresponding γ,γ-disubstituted â,γ-unsaturated esters 11a -d or
γ-lactones 9a -c and 13. A double lithiation process provided â,γ,γ-trisubstituted â,γ-unsaturated
esters 15, 18, and â,γ,γ-trisubstituted γ-lactone 14.
In tr od u ction
unsaturated esters) usually give exclusively R-products,
although highly sterically hindered electrophiles (bulky
ketones) gave exclusively γ-alkylated products. In the
present work, we demonstrate that reaction of deproto-
nated 1 with chlorodiphenylphosphine gives exclusively
the γ-product, which is subsequently smoothly oxidized
in situ to generate 1-(benzotriazol-1-yl)-3-(diphenylphos-
phoryl)-1-ethoxy-(E)-prop-1-ene (3). Phosphine oxide 3
undergoes stereoselective Horner reactions to yield sub-
stituted dienes, the hydrolysis of which, depending on
the conditions, affords convenient routes to both â,γ-
unsaturated esters and γ-lactones.
The Wittig-Horner reaction has frequently been uti-
lized for the preparation of R,â-unsaturated acids and
their esters: it enables easy control of the geometry of
the double bond by an appropriate choice of reagents and
solvent, and the phosphorus reagents are readily availa-
ble.1-4 However, examples of the preparation of â,γ-
unsaturated acids by the Wittig-Horner reaction are
rare.5,6 J anecki and Bodalski7 prepared â,γ-unsaturated
amides via the aminolysis of â-(diethoxyphosphoryl)γ-
lactones, themselves formed by reaction of deprotonated
â-(diethoxyphosphoryl)propionic acid with a carbonyl
compound followed by cyclization. However, direct reac-
tion of â-(diethoxyphosphoryl)-substituted esters with
carbonyl compounds normally occurs at the R-position to
the ester group to give the R-[(diethoxyphosphoryl)-
methyl]-substituted acrylate derivatives8,9 instead of â,γ-
unsaturated esters because the R-proton in the â-(di-
ethoxyphosphoryl)-substituted esters is more acidic than
the â-proton.
Resu lts a n d Discu ssion
3-(Benzotriazol-1-yl)-3-ethoxy-1-propene (1) was previ-
ously prepared in almost quantitative yield by reacting
benzotriazole with acrolein diethyl acetal in “performance
fluid (PF5070)” in an inverse Dean-Stark apparatus;10
we now find that directly heating benzotriazole and
acrolein diethyl acetal in hexane for 6 h affords 1 in 87%
yield.
Ster eoselective Rea ction s of 1-(Ben zotr ia zol-1-
yl)-3-(d ip h en ylp h osp h or yl)-1-eth oxy-1-p r op en e (3)
w ith Ald eh yd es Lea d in g to â,γ-Un sa tu r a ted Ester s.
Treatment of 1 with 1 equiv of BuLi followed by reaction
with chlorodiphenylphosphine and subsequently with
H2O2 gave 1-(benzotriazol-1-yl)-3-(diphenylphosphoryl)-
1-ethoxy-(E)-prop-1-ene (3) in 60% yield, regio- and
stereo-specifically (Scheme 1). No R-product and no
Z-isomer were observed in the NMR spectra of the crude
mixture. This γ-regiospecificity is analogous to the
reaction of the allylic anion from 1 with sterically
hindered diketones.12
Treatment of 3 with 1 equiv of BuLi at -78 °C in THF,
followed by reaction with benzaldehyde at -78 to +20
°C for 4 h, gave diene 4a in 80% yield together with a
small amount of 5a (E,E-:Z,E- ) ca. 8:1, as determined
from the NMR spectra of the crude mixture), which was
removed by column chromatography. Compounds 4b,c
were similarly prepared in 55-71% yields, and again
small amounts of 5b,c (E,E-:Z,Z-, ca. 10:1) were removed
during column chromatography.
We have recently reported the advantageous use of
readily available N-(R-ethoxyallyl)benzotriazole 1 for the
syntheses of functionalized vinyl ketones,10 cyclopro-
panes,11 γ-lactones,11 â,γ-unsaturated carboxylic acids,11
ketones,12 1,4-diketones,12 2-cyclopentenones12 and R-keto
enamines.12 Reactions of deprotonated 1 with diverse
electrophiles (alkyl halides, aldehydes, ketones, and R,â-
X Abstract published in Advance ACS Abstracts, May 1, 1997.
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Wilcox, C. S. Tetrahedron Lett. 1988, 29, 6823 and references cited
therein.
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CRC Press: New York, 1996; p 187.
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The Horner reaction has been extensively investi-
gated.2,3 Addition of a nonstabilized carbanion of a
S0022-3263(97)00164-3 CCC: $14.00 © 1997 American Chemical Society

4132 J . Org. Chem., Vol. 62, No. 12, 1997
Katritzky et al.
Sch em e 1
Sch em e 2
phosphine oxide (Ph2P(O)CH2R) to an aldehyde gives
predominantly an erythro intermediate, which can be
separated by flash column chromatography and crystal-
lization. Stereospecific elimination produces pure (Z)-
alkenes.13-15 However, stabilized ylides produce (E)-
alkenes,2,3 and in the present cases the anions are
stabilized by the â-benzotriazolylvinyl group.
threo and erythro diastereomers (5:1), which were sepa-
rated by column chromatography. Compound 6b was
similarly prepared in 68% yield as a mixture of diaster-
eomers (threo:erythro, 5.5:1 from crude NMR spectra).
Further treatment of 6a ,b with HCl-EtOH-H2O gave
the â-(diphenylphosphoryl)-substituted lactones 7a ,b in
79-80% yields. Analogous γ-substituted â-(diethoxy-
phosphoryl) γ-lactones were previously prepared by LDA-
promoted reactions of â-(diethoxyphosphoryl)propane-
carboxylic acids with carbonyl compounds.7 The E-:Z-
ratios in Wittig-Horner products are determined by the
threo:erythro ratios in the intermediates.3
Rea ction of 3 w ith Keton es for th e Syn th eses of
â,γ-Un sa tu r a ted Ester s 11a -d a n d γ-La cton es 9a -c
a n d 13. Reactions of the deprotonated 1-(benzotriazol-
1-yl)-3-(diphenylphosphoryl)-1-ethoxy-(E)-prop-1-ene (3)
with ketones gave the Horner products 10 even at low
temperatures (-78 °C), although a higher reaction tem-
perature (at 20 °C) can substantially reduce the reaction
time (Scheme 2). The contrast to the aldehyde cases is
probably due to the relatively high thermodynamic
stability of the CdC double bond with three substituents
and the steric kinetic substituents’ effect. Thus, treat-
ment of 3 with 1 equiv of BuLi at -78 °C in THF, followed
by reaction with cyclohexanone at -78 °C for 10 h, gave
1,3-diene 10a in 93% yield. The reaction was also
complete at 20 °C after only 1 h as monitored by TLC.
Compounds 10c,d were obtained in 60-70% yields when
benzophenone and 4-heptanone were employed as the
electrophiles. The structures of 10a ,c,d were fully sup-
ported by NMR spectra and by elemental analyses.
When unsymmetrical acetophenone was used as the
electrophile, the E,E-isomer 10b was produced in 73%
yield along with a small amount of Z,E-isomer (E,E-:Z,E-,
8:1 by 1H NMR spectra). The E,E-structure was sup-
ported by the NOE technique.
Treatment of 4a -c with TsOH·H2O-EtOH readily
afforded the â,γ-unsaturated esters 2a -c in 88-95%
yields. â,γ-Unsaturated esters have previously been
prepared by (i) reaction of organoboranes with either R,â-
unsaturated γ-bromo esters16 or ethyl (dimethylsulfura-
nylidene)acetate,17 (ii) electrocatalyzed carboxylation of
allyl chlorides,18 (iii) carbonylation of (η3-allyl)Fe(CO)3-
(NO),19 (iv) palladium-catalyzed carbonylation of allyl
phosphates, acetates,20 or halides,21 (v) palladium- and
nickel-catalyzed coupling of vinyl bromides with Refor-
masky reagents,22 (vi) isomerization of R,â-unsaturated
esters,23-26 and (vii) treatment of R,â-unsaturated R-bro-
mo esters with dialkyl phosphonates.27 No previous
report has been found for the preparation of â,γ-unsatur-
ated esters via formation of the CdC double bond.
Alternatively, reaction of 3 with benzaldehyde for 5
min at -78 °C, and subsequent quenching with water,
gives hydroxyphosphine 6a in 66% yield as a mixture of
(13) Ochi, M.; Miura, I.; Tokoroyama, T. J . Chem. Soc., Chem.
Commun. 1981, 100.
(14) Buss, A. D.; Warren, S. Tetrahedron Lett. 1983, 24, 3931.
(15) Buss, A. D.; Warren, S. J . Chem Soc., Perkin Trans. 1 1985,
2307.
(16) Brown, H. C.; Nambu, H. J . Am. Chem. Soc. 1970, 92, 1761.
(17) Deng, M.-Z.; Li, N.-S.; Huang, Y.-Z. J . Org. Chem. 1992, 57,
4017.
(18) Folest, J .-C.; Duprilot, J .-M.; Perichon, J .; Robin, Y.; Devynck,
J . Tetrahedron Lett. 1985, 26, 2633.
(19) Nakanishi, S.; Yamamoto, T.; Furukawa, N.; Otsuji, Y. Syn-
thesis 1994, 609.
(20) Murahashi, S.-I.; Imada, Y.; Taniguchi, Y.; Higashiura, S.-Y.
Tetrahedron Lett. 1988, 29, 4945.
(21) Okano, T.; Okabe, N.; Kiji, J . Bull. Chem. Soc. J pn. 1992, 65,
2589.
(22) Fauvarque, J . F.; J utand, A. J . Organomet. Chem. 1981, 209,
109.
(23) Ikeda, Y.; Yamamoto, H. Tetrahedron Lett. 1984, 25, 5181.
(24) Rathke, M. W.; Sullivan, D. Tetrahedron Lett. 1972, 4249.
(25) Kende, A. S.; Toder, B. H. J . Org. Chem. 1982, 47, 163.
(26) Krebs, E.-P. Helv. Chim. Acta 1981, 64, 1023.
(27) Hirao, T.; Fujihara, Y.; Kurokawa, K.; Ohshiro, Y.; Agawa, T.
J . Org. Chem. 1986, 51, 2830.
Hydrolyses of 10, as carried out in the cases of 4,
generated the expected â,γ-unsaturated esters 11a -d in

Syntheses of â,γ-Unsaturated Esters and γ-Lactones
J . Org. Chem., Vol. 62, No. 12, 1997 4133
Sch em e 3
In conclusion, 1-(benzotriazol-1-yl)-3-(diphenylphos-
phoryl)-1-ethoxyprop-1-ene has been shown to be an
efficient )CCH2CO2Et synthon equivalent for the con-
venient stereoselective synthesis of â,γ-unsaturated es-
ters and γ-lactones.
Exp er im en ta l Section
Gen er a l Com m en ts. Melting points were determined on
a hot stage apparatus without correction. 1H (300 MHz) and
13C NMR (75 MHz) spectra were recorded in CDCl3 with TMS
or CDCl3, respectively, as the internal reference. Elemental
analyses and high-resolution mass spectra were performed
within the department. Column chromatography was carried
out on MCB silica gel (230-400 mesh). Tetrahydrofuran
(THF) was freshly distilled from sodium benzophenone. Lithi-
ation reactions were carried out under the protection of dry
nitrogen.
Mod ified P r oced u r e for th e P r ep a r a tion of 3-(Ben zo-
tr ia zol-1-yl)-3-eth oxy-1-p r op en e (1). A mixture of acrolein
diethyl acetal (3.91 g, 30 mmol) and benzotriazole (5.36 g, 45
mmol) in hexane (30 mL) was heated under reflux for 6 h. After
cooling, diethyl ether (300 mL) was added, and the solution
was washed with saturated aqueous Na2CO3 solution (2 × 150
mL) and water (150 mL). Evaporation of the solvent and
separation by column chromatography (hexane/ethyl acetate,
14:1) gave 5.27 g of pure product (87%). The spectral data
are the same as reported in the literature.10
71-99% yields. By contrast, aqueous hydrolysis (H2-
SO4-EtOH-H2O) of 10a ,b,d gave γ-substituted γ-lac-
tones 9a -c in 82-90% yields, probably via the â,γ-
unsaturated acids 8. Conversions of γ,γ-disubstituted
â,γ-unsaturated acids and esters to the corresponding
lactones under acidic conditions have been reported
previously.28-31
Under acidic conditions, similar to those used for the
conversion of 10a ,b,d into 9a -c, no lactone 13 was
formed. Compound 10c formed acid 12 (32%) and the
corresponding ester 11c (50%). Further treatment of 12
in concentrated sulfuric acid at 20 °C converted it into
lactone 13 in 95% yield. Acidic hydrolysis and cyclization
of 11c with AcOH-H2-H2SO4 also easily produced the
lactone 13 in 92% yield. The structures of esters 11a -d
and lactones 9a -c and 13 were confirmed by NMR
spectroscopy and CHN analyses.
P r ep a r a tion of 1-(Ben zotr ia zol-1-yl)-3-(d ip h en ylp h os-
ph or yl)-1-eth oxy-(E)-pr op-1-en e (3). To a solution of 3-(ben-
zotriazol-1-yl)-3-ethoxy-1-propene (1) (4.06 g, 20 mmol) in THF
(100 mL) at -78 °C was added BuLi (1.6 M, 13.8 mL). After
5 min, chlorodiphenylphosphine (4.41 g, 20 mmol) was added,
and the reaction was kept at -78 °C for 3 h and at 20 °C for
1 h. Water (80 mL) and H2O2 (2 mL) were added, and the
mixture was stirred at 20 °C for another 10 h. The solution
was then diluted with water (300 mL) and extracted with
diethyl ether (2 × 150 mL). The organic phase was separated
and dried (MgSO4). Evaporation of the solvent and separation
by column chromatography (hexane/ethyl acetate, 1:4) gave
4.81 g of product: yield 60%; mp 108-110 °C; 1H NMR δ 1.18
(t, 3 H, J ) 7.1 Hz), 3.41-3.56 (m, 4 H), 5.41 (dt, 1 H, J PH
6.0 Hz, J HH ) 8.0 Hz), 7.31-7.60 (m, 9 H), 7.82-7.95 (m, 4
H), 8.03 (d, 1 H, J ) 8.3 Hz); 13C NMR δ 14.4, 28.0 (d, J PC
)
Dou ble Lith ia tion of 1-(Ben zotr ia zol-1-yl)-3-(d i-
p h en ylp h osp h or yl)-1-eth oxy-(E)-p r op -1-en e (3) for
th e P r ep a r a tion of â,γ,γ-Tr isu bstitu ted Ester s 15
a n d 18 a n d â,γ,γ-Tr isu bstitu ted La cton e 14. Strong
activation of the R-methylene protons by the benzotriazo-
1-ylvinyl group in 3 allows the phosphine oxides 3 to
undergo two lithiations. Thus, as shown in Scheme 3,
an alkyl group can be introduced before the Horner
reaction is carried out. Treatment of 3 with 1 equiv of
BuLi, followed by quenching with methyl iodide and then
with another equiv of BuLi, and finally with cyclohex-
anone, gives diene 16 in 65% yield. Hydrolyses under
conditions similar to those used for the preparations of
11 and 9 convert 16 into the â,γ,γ-trisubstituted ester
15 (98%) and the â,γ,γ-trisubstituted lactone 14 (80%),
respectively. However, reaction of 3 with benzaldehyde
in a similar sequence (see Scheme 3) gives compound 17
as a mixture of two stereoisomers (E,E-:Z,E-, ca. 2:1):
evidently, the tertiary anion, formed after the second
deprotonation of 3, reacts with benzaldehyde with poor
stereoselectivity. Hydrolyses of 17, carried out as in the
case of 4, generated the expected â,γ-unsaturated ester
18 in 96% yield.
)
69.6 Hz), 66.4, 98.0 (d, J PC ) 8.6 Hz), 110.4, 119.5, 124.2, 128.2,
128.4 (d, J PC ) 11.9 Hz), 130.7 (d, J PC ) 9.3 Hz), 131.4, 131.7,
132.1, 132.7, 144.9 (d, J PC )12.8 Hz), 145.1. Anal. Calcd for
C23H22N3O2P: C, 68.48; H, 5.50; N, 10.42. Found: C, 68.35;
H, 5.63; N, 10.31.
Gen er a l P r oced u r e for th e P r ep a r a tion of Dien es
4a -c a n d 10a -d . To a solution of 1-(benzotriazol-1-yl)-3-
(diphenylphosphoryl)-1-ethoxy-(E)-prop-1-ene (3) (2.82 g, 7
mmol) in dry THF (70 mL) at -78 °C was added BuLi (1.6 M,
4.8 mL). The solution was stirred at this temperature for 5
min, and the appropriate electrophile (benzaldehyde, octanal,
3-phenylpropionaldehyde, cyclohexanone, acetophenone, ben-
zophenone, 4-heptanone dipropyl ketone, 7 mmol) was added.
After being stirred at -78 °C for 3 h, the solution was allowed
to warm to room temperature and kept for an additional hour.
Water (50 mL) was added and the mixture extracted with
diethyl ether (2 × 100 mL) and dried over anhydrous MgSO4.
Evaporation of the solvent gave a residue, which was chro-
matographed on silica gel (hexane/ethyl acetate, 10:1).
1-(Be n zot r ia zol-1-yl)-1-e t h oxy-(E ,E )-u n d e ca -1,3-d i-
1
en e (4a ) was obtained as a colorless oil: yield 80%; H NMR
δ 0.91 (t, 3 H, J ) 6.8 Hz), 1.21-1.55 (m, 13 H), 2.20 (q, 2 H,
J ) 6.9 Hz), 3.78 (q, 2 H, J ) 7.1 Hz), 5.84-5.97 (m, 1 H),
6.09 (d, 1 H, J ) 10.9 Hz), 6.49 (dd, 1 H, J ) 15.4 and 10.9
Hz), 7.40 (t, 1 H, J ) 7.4 Hz), 7.53 (t, 1 H, J ) 7.4 Hz), 7.75 (d,
1 H, J ) 8.5 Hz), 8.08 (d, 1 H, J ) 8.3 Hz); 13C NMR δ 13.9,
14.6, 22.5, 29.0, 29.1, 31.7, 33.0, 67.3, 109.8, 111.1, 119.9, 122.2,
124.3, 128.2, 132.1, 136.8, 141.7, 145.7. Anal. Calcd for
C19H27N3O: C, 72.81; H, 8.68; N, 13.41. Found: C, 73.06; H,
9.14; N, 13.72.
(28) Cason, J .; Rinehart, K. L, jr. J . Org. Chem. 1955, 20, 1591.
(29) Ansell, M. F.; Palmer, M. H. J . Chem. Soc. 1963, 2640.
(30) J ohnson, W. S.; Petersen, J . W.; Schneider, W. P. J . Am. Chem.
Soc. 1947, 69, 74.
(31) J ohnson, W. S.; Miller, M. W. J . Am. Chem. Soc. 1950, 72, 511.

4134 J . Org. Chem., Vol. 62, No. 12, 1997
Katritzky et al.
1-(Ben zotr ia zol-1-yl)-1-eth oxy-4-p h en yl-(E,E)-bu ta -1,3-
d ien e (4b) was obtained as a colorless oil: yield 55%; 1H NMR
δ 1.36 (t, 3 H, J ) 7.1 Hz), 3.83 (q, 2 H, J ) 7.1 Hz), 6.28 (d,
1 H, J ) 11.0 Hz), 6.69 (d, 1 H, J ) 15.9 Hz), 7.18-7.62 (m, 8
H), 7.77 (d, 1 H, J ) 8.3 Hz), 8.09 (d, 1 H, J ) 8.3 Hz); 13C
NMR δ 14.5, 67.6, 109.1, 111.0, 119.8, 120.9, 124.3, 126.1,
127.5, 128.2, 128.3, 131.7, 133.0, 136.9, 143.4, 145.5. Anal.
Calcd for C18H17N3O: C, 74.20; H, 5.88; N, 14.42. Found: C,
73.71; H, 6.26; N, 14.28.
1-(Ben zotr ia zol-1-yl)-1-eth oxy-6-p h en yl-(E,E)-h exa -1,3-
d ien e (4c) was obtained as a colorless oil: yield 71%; 1H NMR
δ 1.31 (t, 3 H, J ) 7.1 Hz), 2.48-2.62 (m, 2 H), 2.79 (t, 2 H, J
) 7.2 Hz), 3.76 (q, 2 H, J ) 7.1 Hz), 5.87-5.99 (m, 1 H), 6.10
(d, 1 H, J ) 10.8 Hz), 6.52 (dd, 1 H, J ) 15.4, 10.8 Hz), 7.17-
7.37 (m, 5 H), 7.41 (t, 1 H, J ) 7.3 Hz), 7.53 (t, 1 H, J ) 7.7
Hz), 7.75 (d, 1 H, J ) 8.3 Hz), 8.09 (d, 1 H, J ) 8.3 Hz); 13C
NMR δ 14.6, 34.7, 35.5, 67.4, 109.5, 111.2, 120.0, 123.0, 124.4,
125.8, 128.2, 128.3, 132.5, 135.3, 141.4, 142.1, 145.7. Anal.
Calcd for C20H21N3O: C, 75.21; H, 6.63; N, 13.16. Found: C,
75.16; H, 6.68; N, 13.08.
1-(Ben zotr ia zol-1-yl)-1-eth oxy-4,4-cycloh exylbu ta -1,3-
d ien e (10a ) was obtained as a colorless oil: yield 93%; 1H
NMR δ 1.33 (t, 3 H, J ) 7.1 Hz), 1.24-1.34 (m, 6 H), 2.09-
2.19 (m, 4 H), 3.77 (q, 2 H, J ) 6.9 Hz), 6.23 (d, 1 H, J ) 11.4
Hz), 6.34 (d, 1 H, J ) 11.4 Hz), 7.39 (t, 1 H, J ) 7.2 Hz), 7.52
(t, 1 H, J ) 7.2 Hz), 7.75 (d, 1 H, J ) 8.4 Hz), 8.06 (d, 1 H, J
) 8.4 Hz); 13C NMR δ 14.5, 26.4, 27.4, 28.3, 29.3, 37.3, 67.0,
105.5, 111.0, 113.6, 119.6, 124.1, 128.0, 131.8, 142.0, 145.4,
145.8. Anal. Calcd for C17H21N3O: C, 72.06; H, 7.47; N, 14.83.
Found: C, 71.80; H, 7.64; N, 14.61.
1-(Ben zot r ia zol-1-yl)-1-et h oxy-4-p h en ylp en t a -1,3-d i-
en e (10b) was obtained as a colorless oil: yield 73%; 1H NMR
δ 1.33 (t, 3 H, J ) 7.2 Hz), 2.20 (s, 3 H), 3.80 (q, 2 H, J ) 7.2
Hz), 6.50 (d, 1 H, J ) 11.4 Hz), 6.93 (d, 1 H, J ) 11.4 Hz),
7.28-7.48 (m, 4 H), 7.52-7.60 (m, 3 H), 7.80 (d, 1 H, J ) 8.3
Hz), 8.11 (d, 1 H, J ) 8.4 Hz); 13C NMR δ 14.7, 16.3, 67.7,
106.4, 111.2, 119.0, 120.0, 124.5, 125.6, 127.3, 128.3, 128.4,
132.0, 138.1, 142.8, 143.8, 145.8. Anal. Calcd for C19H19N3O:
C, 74.73; H, 6.27; N, 13.76. Found: C, 74.28; H, 6.51; N, 13.43.
1-(Ben zotr ia zol-1-yl)-1-eth oxy-4,4-d ip h en ylbu ta -1,3-d i-
en e (10c): yield 70%; mp 72-74 °C; 1H NMR δ 1.37 (t, 3 H, J
) 7.2 Hz), 3.84 (q, 2 H, J ) 7.2 Hz), 6.23 (d, 1 H, J ) 11.4 Hz),
7.20 (d, 1 H, J ) 11.4 Hz), 7.22-7.40 (m, 11 H), 7.47 (t, 1 H,
J ) 7.2 Hz), 7.68 (d, 1 H, J ) 8.4 Hz), 8.01 (d, 1 H, J ) 8.4
Hz); 13C NMR δ 14.7, 67.6, 107.3, 111.0, 119.7, 119.9, 124.4,
127.5, 128.1, 128.2, 128.3, 130.1, 131.8, 139.1, 141.9, 144.0,
144.2, 145.5. Anal. Calcd for C24H21N3O: C, 78.45; H, 5.76;
N, 11.44. Found: C, 78.82; H, 5.86; N, 11.44.
3.24 (d, 2 H, J ) 7.0 Hz), 4.18 (q, 2 H, J ) 7.1 Hz), 6.25-6.40
(m, 1 H), 6.50 (d, 1 H, J ) 15.9 Hz), 7.20-7.45 (m, 5 H); 13C
NMR δ 14.1, 38.3, 60.6, 121.7, 126.1, 127.4, 128.4, 133.2, 136.8,
171.3. Anal. Calcd for C12H14O2: C, 75.76; H, 7.42. Found:
C, 75.78; H, 7.81.
Eth yl 6-p h en yl-3-h exen oa te (2c) was obtained as a
1
colorless oil: yield 94%; H NMR δ 1.24 (t, 3 H, J ) 7.1 Hz),
2.30-2.40 (m, 2 H), 2.69 (t, 2 H, J ) 7.4 Hz), 3.00 (d, 2 H, J )
4.8 Hz), 4.12 (q, 2 H, J ) 7.1 Hz), 5.50-5.65 (m, 2 H), 7.12-
7.21 (m, 3 H), 7.22-7.32 (m, 2 H); 13C NMR δ 14.1, 34.1, 35.5,
38.0, 60.3, 122.3, 125.7, 128.1, 128.3, 133.5, 141.6, 171.8. Anal.
Calcd for C14H18O2: C, 77.03; H, 8.31. Found: C, 77.47; H,
8.24.
Eth yl 3-cycloh exylid en ep r op a n oa te (11a ) was obtained
1
as a colorless oil:32 yield 90%; H NMR δ 1.27 (t, 3 H, J ) 7.2
Hz), 1.45-1.65 (m, 6 H), 2.07-2.18 (m, 4 H), 3.04 (d, 2 H, J )
7.2 Hz), 4.14 (q, 2 H, J ) 7.2 Hz), 5.26 (t, 1 H, J ) 7.2 Hz); 13
C
NMR δ 14.1, 26.6, 27.4, 28.3, 28.8, 32.9, 36.9, 60.3, 112.4, 143.2,
172.4.
Eth yl 4-p h en yl-(E)-3-p en ten oa te (11b) was obtained as
a colorless oil: yield 88%; 1H NMR δ 1.25 (t, 3 H, J ) 7.1 Hz),
2.06 (s, 3 H), 3.22 (d, 2 H, J ) 7.0 Hz), 4.14 (q, 2 H, J ) 7.1
Hz), 5.95 (t, 1 H, J ) 7.1 Hz), 7.15-7.42 (m, 5 H); 13C NMR δ
14.1, 16.0, 34.4, 60.5, 119.2, 125.6, 126.9, 128.0, 137.8, 143.0,
171.6. Anal. Calcd for C13H16O2: C, 76.44; H, 7.90. Found:
C, 76.31; H, 7.86.
Eth yl 4,4-d ip h en yl-3-bu ten oa te (11c) was obtained as a
1
colorless oil: yield 71%; H NMR δ 1.23 (t, 3 H, J ) 7.1 Hz),
3.14 (d, 2 H, J ) 7.4 Hz), 4.14 (q, 2 H, J ) 7.1 Hz), 6.27 (t, 1
H, J ) 7.4 Hz), 7.08-7.46 (m, 10 H); 13C NMR δ 14.1, 35.4,
60.5, 120.4, 127.2, 127.3, 128.2, 129.6, 139.1, 141.8, 144.5,
171.6. Anal. Calcd for C18H18O2: C, 81.16; H, 6.81. Found:
C, 80.75; H, 6.85.
Eth yl 4-p r op yl-3-h ep ten oa te (11d ) was obtained as a
colorless oil: yield 99%; 1H NMR δ 0.85-0.95 (m, 6 H), 1.26 (t,
3 H, J ) 7.1 Hz), 1.31-1.51 (m, 4 H), 2.00 (t, 4 H, J ) 7.1 Hz),
3.05 (d, 2 H, J ) 7.1 Hz), 4.13 (q, 2 H, J ) 7.1 Hz), 5.34 (t, 1
H, J ) 7.1 Hz); 13C NMR δ 13.7, 14.0, 14.1, 21.1, 21.3, 32.3,
33.6, 38.9, 60.3, 116.0, 143.0, 172.4. Anal. Calcd for
C12H22O2: C, 72.68; H, 11.18. Found: C, 72.94; H, 11.06.
Eth yl 3-m eth yl-4,4-p en ten o-3-bu ten oa te (15) was ob-
1
tained as a colorless oil: yield 98%; H NMR δ 1.26 (t, 3 H, J
) 7.1 Hz), 1.46-1.62 (m, 6 H), 1.76 (s, 3 H), 2.13-2.23 (m, 4
H), 3.08 (s, 2 H), 4.13 (q, 2 H, J ) 7.2 Hz); 13C NMR δ 14.1,
18.6, 26.7, 27.8, 27.9, 30.6, 30.8, 39.4, 60.2, 117.4, 136.8, 172.1.
Anal. Calcd for C12H20O2: C, 73.43; H, 10.27. Found: C,
73.20; H, 10.43.
1-(Ben zot r ia zol-1-yl)-1-et h oxy-4-p r op ylh ep t a -1,3-d i-
en e (10d ) was obtained as a colorless oil: yield 60%; 1H NMR
δ 0.93 (t, 3 H, J ) 7.4 Hz), 0.97 (t, 3 H, J ) 7.4 Hz), 1.34 (t, 3
H, J ) 7.1 Hz), 1.42-1.6 (m, 4 H), 2.12-2.25 (m, 4 H), 3.79 (q,
2 H, J ) 7.0 Hz), 6.28-6.38 (m, 2 H), 7.41 (t, 1 H, J ) 7.2 Hz),
7.54 (t, 1 H, J ) 7.2 Hz), 7.77 (d, 1 H, J ) 8.4 Hz), 8.09 (d, 1
H, J ) 8.3 Hz); 13C NMR δ 13.8, 14.0, 14.7, 21.3, 33.0, 39.7,
67.3, 106.4, 111.2, 116.8, 119.9, 124.3, 128.1, 132.2, 142.0,
145.7, 146.2. Anal. Calcd for C18H25N3O: C, 72.21; H, 8.42;
N, 14.03. Found: C, 71.92; H, 8.80; N, 14.25.
Gen er a l P r oced u r e for th e P r ep a r a tion of â,γ-Un sa t-
u r a ted Ester s 2a -c, 11a -d , 15 a n d 18. A mixture of diene
4a (or 4b,c, 10a -d , 16, 17) (2 mmol) and p-toluenesulfonic
acid monohydrate (10 mg) in anhydrous ethanol (20 mL) was
heated under reflux for 40 h. After cooling, diethyl ether (150
mL) was added, and the solution was washed with saturated
Na2CO3 solution (2 × 100 mL). Evaporation of the solvent
gave a residue, which was chromatographed on silica gel
(hexane/ethyl acetate, 50:1).
Eth yl 3-eth yl-4-p h en yl-3-bu ten oa te (18) was obtained as
a colorless oil: yield 96% (a mixture of E- and Z- isomers, ratio
1
ca. 2.3:1 from H NMR): 1H NMR (peaks for the minor isomer
are given in square brackets) δ 1.13 (t, 3 H, J ) 7.6 Hz) [1.05
(t, 3 H, J ) 7.6 Hz)], 1.26 (t, 3 H, J ) 7.1 Hz), 2.27 (q, 2 H, J
) 7.4 Hz) [2.34 (q, 2 H, J ) 7.4 Hz)], 3.21 (s, 3 H) [3.16 (s 3
H)], 4.16 (q, 2 H, J ) 7.1 Hz), 6.49 (s, 1 H) [6.38 (s, 1 H)],
7.13-7.38 (m, 5 H); 13C NMR (it is difficult to assign all of the
carbon peaks to two isomers, so all peaks are listed) δ 12.3,
12.6, 14.1, 24.0, 30.4, 37.0, 42.4, 60.5, 60.6, 126.4, 126.5, 127.4,
128.0, 128.1, 128.4, 128.5, 128.7, 136.9, 137.4, 137.6, 171.6,
171.7. Anal. Calcd for C14H18O2: C, 77.03; H, 8.31. Found:
C, 77.39; H, 8.40.
Gen er a l P r oced u r e for th e P r ep a r a tion of 6a ,b. To a
solution of 1-(benzotriazol-1-yl)-3-(diphenylphosphoryl)-1-
ethoxy-(E)-prop-1-ene (3) (2.02 g, 5 mmol) in THF (50 mL) at
-78 °C was added BuLi (1.6 M, 3.8 mL). The solution was
stirred at this temperature for 5 min, and the appropriate
electrophile (benzaldehyde or p-tolualdehyde, 5 mmol) was
added. After being stirred at -78 °C for an additional 5 min,
water (50 mL) was added, and the mixture was extracted with
diethyl ether (2 × 100 mL) and dried over anhydrous MgSO4.
Evaporation of the solvent gave a residue, which was chro-
matographed on silica gel (hexane/ethyl acetate, 3:2). In the
case of 6a , two diastereomers have been isolated and charac-
Eth yl 3-u n d ecen oa te (2a ) was obtained as a colorless oil:
yield 95%; 1H NMR δ 0.89 (t, 3 H, J ) 6.9 Hz), 1.20-1.45 (m,
13 H), 2.03 (q, 2 H, J ) 7.0 Hz), 3.02 (d, 2 H, J ) 5.3 Hz), 4.14
(q, 2 H, J ) 7.1 Hz), 5.47-5.65 (m, 1 H); 13C NMR δ 14.0, 14.1,
22.6, 29.1, 29.3, 31.8, 32.4, 38.1, 60.3, 121.5, 134.7, 172.0.
Anal. Calcd for C13H24O2: C, 73.54; H, 11.39. Found: C,
73.28; H, 11.56.
Eth yl 4-p h en yl-3-bu ten oa te (2b) was obtained as a
1
colorless oil: yield 88%; H NMR δ 1.29 (t, 3 H, J ) 7.1 Hz),
(32) Piva, O. Tetrahedron 1994, 50, 13687.

Syntheses of â,γ-Unsaturated Esters and γ-Lactones
J . Org. Chem., Vol. 62, No. 12, 1997 4135
terized; in the case of 6b, only the major isomer was isolated
and characterized.
γ,γ-Sp ir o[cycloh exa n e-γ-bu tyr ola cton e] (9a ) was ob-
tained as a colorless oil (lit.33 80-110 °C/mmHg): yield 82%;1H
NMR δ 1.37-1.87 (m, 10 H), 2.03 (t, 2 H, J ) 8.7 Hz), 2.58 (t,
2 H, J ) 8.4 Hz); 13C NMR δ 22.3, 24.7, 28.3, 32.5, 36.6, 86.1,
176.5.
1-(Ben zotr iazol-1-yl)-3-(diph en ylph osph or yl)-1-eth oxy-
4-h yd r oxy-4-p h en yl-1-bu ten e (6a ) was obtained as two
diastereomers. Isomer I: yield 11%; mp 148-151 °C; 1H NMR
δ 0.80 (t, 3 H, J ) 7.2 Hz), 2.48-2.60 (m, 1 H), 3.08-3.20 (m,
1 H), 4.00 (dd, 1 H, J ) 11.5, 7.2 Hz), 5.31 (s, 1 H), 5.53 (d, 1
H, J ) 8.5 Hz), 5.77 (dd, 1 H, J ) 11.3, 5.6 Hz), 7.10-7.22 (m,
2 H), 7.27-7.50 (m, 9 H), 7.58-7.65 (m, 3 H), 7.88-8.00 (m, 3
H), 8.03-8.15 (m, 2 H); 13C NMR δ 14.1, 45.1 (d, J PC ) 67.7
Hz), 66.1, 71.3, 98.7, 110.2, 119.4, 124.1, 125.6, 127.1, 127.8,
γ-Meth yl-γ-p h en yl-γ-bu tyr ola cton e (9b) was obtained as
a colorless oil (lit.30 140-145 °C/mmHg): yield 89%; 1H NMR
δ 1.72 (s, 3 H), 2.36-2.72 (m, 4 H), 7.27-7.50 (m, 5 H); 13C
NMR δ 28.7, 29.1, 35.9, 86.7, 123.9, 127.4, 128.4, 144.2, 176.2.
γ,γ-Dim eth yl-γ-bu tyr ola cton e (9c) was obtained as a
1
colorless oil: yield 79%; H NMR δ 0.95 (t, 6 H, J ) 7.4 Hz),
128.0, 128.1, 128.2, 128.8 (d, J PC ) 11.6 Hz), 130.7 (d, J PC
)
1.26-1.46 (m, 4 H), 1.56-1.70 (m, 4 H), 2.04 (t, 2 H, J ) 8.5
Hz), 2.58 (t, 2 H, J ) 8.5 Hz); 13C NMR δ 14.0, 16.5, 28.8, 30.5,
40.7, 88.7, 176.7. Anal. Calcd for C10H18O2P: C, 70.55; H,
10.66. Found: C, 70.26; H, 10.97.
8.9 Hz), 131.8, 131.9, 132.1 (d, J PC ) 2.5 Hz), 141.9, 144.9,
145.1 (d, J PC ) 12.4 Hz). Anal. Calcd for C30H28N3O3P: C,
70.72; H, 5.54; N, 8.25. Found: C, 70.96; H, 5.39; N, 8.28.
Isomer II: yield 55%; mp 159-165 °C; 1H NMR δ 1.01 (t, 3 H,
J ) 7.2 Hz), 2.72-2.82 (m, 1 H), 3.02-3.17 (m, 1 H), 4.27 (q,
1 H, J ) 10.0 Hz), 4.80 (dd, 1 H, J ) 11.5 and 5.8 Hz), 5.12 (t,
1 H, J ) 9.0 Hz), 6.76 (d, 1 H, J ) 7.8 Hz), 7.18-8.17 (m, 19
H); 13C NMR δ 14.5, 45.3 (d, J PC ) 68.3 Hz), 66.0, 74.4, 101.6,
110.0, 119.6, 124.3, 127.0, 127.7, 127.9, 128.2, 128.3, 130.0 (d,
J PC ) 9.1 Hz), 131.4, 131.9, 132.0, 141.8 (d, J PC ) 11.4 Hz),
â-Meth yl-γ,γ-cycloh exyl-γ-bu tyr ola cton e (14) was ob-
1
tained as a colorless oil: yield 80%; H NMR δ 1.06 (d, 3 H, J
) 6.6 Hz), 1.20-1.80 (m, 10 H), 2.20-2.35 (m, 2 H), 2.58-
2.78 (m, 1 H); 13C NMR δ 14.0, 21.4, 22.2, 25.0, 30.4, 35.7,
36.3, 39.0, 87.7, 175.7. Anal. Calcd for C10H16O2: C, 71.39;
H, 9.59. Found: C, 71.36; H, 10.05.
Hyd r olysis of Dien e 10c for th e P r ep a r a tion of 12 a n d
11c. A mixture of diene 10c (1.22 g, 3.32 mmol), hydrochloric
acid (1 mL), ethanol (15 mL), and water (15 mL) was heated
under reflux for 24 h. After cooling, diethyl ether (150 mL)
was added, and the solution was washed with saturated Na2-
CO3 solution (2 × 100 mL). Evaporation of the solvent gave a
residue, which was chromatographed on silica gel (hexane/
ethyl acetate, 33:1) to give 4,4-diphenyl-3-butenoic acid (12)
(0.25 g, 32%) and the ester 11c (0.44 g, 50%). Compound 11c
showed identical spectroscopic features as that previously
obtained.
4,4-Dip h en yl-3-bu ten oic a cid (12): yield 32%; mp 116-
117 °C (lit.30 mp 115-116 °C); 1H NMR δ 3.20 (d, 2 H, J ) 7.4
Hz), 6.25 (t, 1 H, J ) 7.4 Hz), 7.15-7.42 (m, 11 H); 13C NMR
δ 35.1, 119.4, 127.3, 127.4, 128.1, 128.3, 129.6, 139.0, 141.7,
145.2, 178.3.
Con ver sion of 4,4-Dip h en yl-3-bu ten oic Acid 12 to γ,γ-
Dip h en yl-γ-bu tyr ola cton e 13. 4,4-Diphenyl-3-butenoic acid
(12) (0.13 g, 0.5 mmol) was dissolved in concd sulfuric acid (5
mL) at room temperature, and the solution was kept for 0.5
h. The mixture was then poured into ice-water (ca. 50 mL),
extracted with ether (50 mL), and washed with saturated Na2-
CO3 solution (50 mL). Evaporation of the solvent gave the
pure product 13 (0.12 g): yield 92%; mp 88-89 °C (lit.30 mp
87-90 °C); 1H NMR δ 2.54 (t, 2 H, J ) 7.7 Hz), 2.88 (t, 2 H, J
) 7.7 Hz), 7.21-7.51 (m, 10 H); 13C NMR δ 28.9, 35.5, 89.6,
125.3, 127.8, 128.5, 142.9, 175.9.
Con ver sion of Eth yl 4,4-Dip h en yl-3-bu ten oa te 11c to
γ,γ-Dip h en yl-γ-bu tyr ola cton e (13). Ester 11c (0.27 g, 1
mmol) was heated under reflux in a mixture of water (10 mL)
and acetic acid (10 mL) for 10 h. After cooling, concd sulfuric
acid (10 mL) was added and the solution stirred for 24 h.
Water (50 mL) was then added, and the whole mixture was
extracted with diethyl ether (2 × 100 mL) and washed with
saturated Na2CO3 solution (2 × 100 mL). Evaporation of the
solvent gave the expected γ,γ-diphenyl-γ-butyrolactone (13)
(0.22 g, 92%). Compound 13 showed spectroscopic features
identical to those previously obtained.
144.4 (d, J PC
C30H28N3O3P: C, 70.72; H, 5.54; N, 8.25. Found: C, 70.95; H,
5.69; N, 7.98.
) 12.5 Hz), 145.0. Anal. Calcd for
1-(Ben zotr iazol-1-yl)-3-(diph en ylph osph or yl)-1-eth oxy-
4-h yd r oxy-4-(4-m eth ylp h en yl)-1-bu ten e (6b) was obtained
as two diastereomers. The major isomer was isolated and
characterized: yield 68%; mp 174-179 °C; 1H NMR δ 0.82 (t,
3 H, J ) 7.2 Hz), 2.26 (s, 3 H), 2.47-2.61 (m, 1 H), 3.08-3.12
(m, 1 H), 3.92 (dd, 1 H, J ) 11.4, 6.9 Hz), 5.06 (s, 1 H), 5.43 (d,
1 H, J ) 8.4 Hz), 5.70 (dd, 1 H, J ) 11.4, 5.7 Hz), 7.07-7.17
(m, 3 H), 7.25-7.53 (m, 7 H), 7.55-7.68 (m, 3 H), 7.85-7.92
(m, 2 H), 7.98 (d, 1 H, J ) 8.1 Hz), 8.05-8.12 (m, 2 H); 13C
NMR δ 14.3, 20.9, 45.2 (d, J PC ) 67.1 Hz), 66.3, 71.5, 98.9,
110.5, 119.8, 124.3, 125.7, 128.1, 128.3, 128.6 (d, J PC ) 11.4
Hz), 129.0 (d, J PC ) 11.4 Hz), 130.7, 130.9, 131.0, 132.2 (d,
J PC ) 15.0 Hz), 136.9, 138.8 (d, J PC ) 12.5 Hz), 145.2. Anal.
Calcd for C31H30N3O3P: C, 71.12; H, 5.78; N, 8.03. Found: C,
70.89; H, 5.86; N, 7.94.
Gen er a l P r oced u r e for th e P r ep a r a tion of La cton es
7a ,b. A mixture of hydroxyphosphine oxide 6a (Isomer II) or
6b (2 mmol), hydrochloric acid (5 mL), ethanol (25 mL), and
water (25 mL) was heated under reflux for 24 h. After cooling,
diethyl ether (150 mL) was added, and the solution was
washed with saturated Na2CO3 solution (2 × 100 mL).
Evaporation of the solvent gave a residue, which was chro-
matographed on silica gel (hexane/ethyl acetate, 15:1).
â-(Diph en ylph osph or yl)-γ-ph en yl-γ-bu tyr olacton e (7a):
yield 80%; mp 170-174 °C; 1H NMR δ 2.67-2.84 (m, 1 H),
3.07-3.26 (m, 1 H), 3.44-3.52 (m 1 H), 5.71 (dd, 1 H, J ) 11.3,
8.5 Hz), 6.88-6.99 (m, 2 H), 7.02-7.32 (m, 5 H), 7.33-7.58
(m, 6 H), 7.70-7.82 (m, 2 H); 13C NMR δ 29.9, 43.2 (d, J PC
73.0 Hz), 80.3 (d, J PC ) 2.3 Hz), 126.2, 128.3, 128.4, 128.5,
128.6, 128.9, 129.0, 130.4 (d, J PC ) 9.1 Hz), 130.8 (d, J PC
)
)
9.4 Hz), 132.0 (d, J PC ) 2.7 Hz), 132.3 (d, J PC ) 3.1 Hz), 137.8,
173.8 (d, J PC ) 11.7 Hz). Anal. Calcd for C22H19O3P: C, 72.92;
H, 5.28. Found: C, 73.11; H, 5.42.
â-(Dip h en ylp h osp h or yl)-γ-(4-m eth ylp h en yl)-γ-bu tyr o-
1
la cton e (7b): yield 79%; mp 178-183 °C; H NMR δ 2.24 (s,
Gen er a l P r oced u r e for th e P r ep a r a tion of Dien es 16
a n d 17. To a solution of 1-(benzotriazol-1-yl)-3-(diphenylphos-
phoryl)-1-ethoxy-(E)-prop-1-ene (3) (2.02 g, 5 mmol) in THF
(50 mL) at -78 °C was added BuLi (1.6 M, 3.2 mL). After the
mixture was stirred at this temperature for 5 min, the
appropriate electrophile (MeI or EtI, 5 mmol) was added and
the solution warmed to room temperature and kept for 1 h.
The solution was cooled to -78 °C, BuLi (1.6 M, 3.2 mL) was
added, and after 5 min the appropriate electrophile (cyclohex-
anone or benzaldehyde, 5 mmol) was added and the solution
gradually warmed to room temperature and kept for 1 h.
Water (50 mL) was then added, and the mixture was extracted
with diethyl ether (2 × 100 mL) and dried over anhydrous
3 H), 2.68-2.73 (m, 1 H), 3.05-3.21 (m, 1 H), 3.41-3.57 (m, 1
H), 5.68 (dd, 1 H, J ) 11.5, 8.3 Hz), 6.83 (d, 2 H, J ) 8.4 Hz),
6.89 (d, 2 H, J ) 8.2 Hz), 7.19-7.29 (m, 2 H), 7.32-7.58 (m, 6
H), 7.70-7.85 (m, 2 H); 13C NMR δ 20.7, 29.6, 42.7 (d, J PC
)
72.8 Hz), 80.1, 125.9, 128.1, 128.2, 128.4, 128.6, 128.8, 130.1
(d, J PC ) 9.1 Hz), 130.6 (d, J PC ) 9.1 Hz), 131.7, 132.0, 134.6,
138.3, 173.8 (d, J PC ) 11.4 Hz). Anal. Calcd for C23H21O3P:
C, 73.40; H, 5.62. Found: C, 73.18; H, 5.67.
Gen er a l P r oced u r e for th e P r ep a r a tion of La cton es
9a -c a n d 14. A mixture of diene 10a (or 10b,d , 16) (3 mmol),
hydrochloric acid (1 mL), ethanol (15 mL), and water (15 mL)
was heated under reflux for 24 h. After cooling, diethyl ether
(150 mL) was added, and the solution was washed with
saturated Na2CO3 solution (2 × 100 mL). Evaporation of the
solvent gave a residue, which was chromatographed on silica
gel (hexane/ethyl acetate, 10:1).
(33) J acobson, R. M.; Lahm, G. P.; Clader, J . W. J . Org. Chem. 1980,
45, 395.

4136 J . Org. Chem., Vol. 62, No. 12, 1997
Katritzky et al.
1
MgSO4. Evaporation of the solvent gave a residue that was
chromatographed on silica gel (hexane/ethyl acetate, 10:1).
1-(Ben zotr ia zol-1-yl)-1-eth oxy-4,4-cycloh exyl-3-m eth -
ylbu ta -1,3-d ien e (16) was obtained as a colorless oil: yield
65%; 1H NMR δ 1.31 (t, 3 H, J ) 7.2 Hz), 1.47-1.67 (m, 6 H),
2.07 (s, 3 H), 2.20-2.38 (m, 4 H), 3.75 (q, 2 H, J ) 7.2 Hz),
6.20 (s, 1 H), 7.39 (t, 1 H, J ) 7.7 Hz), 7.52 (t, 1 H, J ) 8.0
Hz), 7.75 (d, 1 H, J ) 8.2 Hz), 8.07 (d, 1 H, J ) 8.2 Hz); 13C
NMR δ 14.7, 26.5, 27.7, 30.5, 31.5, 66.8, 109.1, 111.0, 119.8,
124.1, 128.0, 132.2, 141.0, 141.9, 145.5. Anal. Calcd for
C18H23N3O: C, 72.70; H, 7.80; N, 14.13. Found: C, 72.35; H,
8.02; N, 13.99.
of E,E- and Z,E-isomers, ratio ca. 2:1 from H NMR); 1H NMR
(peaks for the minor isomer are given in square brackets) δ
1.25-1.38 (m, 6 H), 2.62-2.78 (m, 2 H), 3.68-3.82 (m, 2 H),
6.20 (s, 1 H) [5.92 (s, 1 H)], 6.55 (s, 1 H) [6.85 (s, 1 H)], 7.13-
7.48 (m, 6 H), 7.69 (d, 1 H, J ) 8.3 Hz) [7.78 (d, 1 H, J ) 8.2
Hz)], 8.09 (t, 1 H, J ) 9.4 Hz); 13C NMR (all peaks are listed,
due to the difficulty of the assignment) δ 13.9, 14.1, 14.6, 23.2,
29.3, 66.8, 106.6, 110.8, 110.9, 111.0, 111.6, 119.9, 124.3, 124.4,
126.6, 128.0, 128.1, 128.2, 128.3, 128.6, 129.0, 129.8, 131.3,
132.3, 136.7, 137.4, 137.5, 137.8, 142.2, 143.4, 145.5, 145.6.
Anal. Calcd for C20H21N3O: C, 75.21; H, 6.63; N, 13.16.
Found: C, 75.56; H, 6.98; N, 13.46.
1-(Ben zotr ia zol-1-yl)-1-eth oxy-3-eth yl-4-p h en ylbu t-1,3-
d ien e (17) was obtained as a colorless oil: yield 51% (a mixture
J O9701647