Syntheses of α,β-unsaturated carbonyl compounds from the reactions of monosubstituted ozonides with stable phosphonium ylides

Article abstract of DOI:10.1016/S0040-4020(00)00903-0

Ozonides derived from terminal alkenes reacted with 1.3 mol equiv. of stable phosphonium ylides to give (E)-αβ-unsaturated carbonyl compounds in good to excellent yields. No reducing agent is needed in the reaction. However, alkoxyalkyl-substituted ozonides afforded a mixture of (Z)- and (E)-αβ-unsaturated carbonyl compounds under similar condition. The E/Z isomeric ratio is affected by the position of the heteroatom in the substituent of the ozonides. The possible mechanism of this reaction will be discussed. (C) 2000 Elsevier Science Ltd.

Full text of DOI:10.1016/S0040-4020(00)00903-0

TETRAHEDRON
Pergamon
Tetrahedron 56 (2000) 9269±9279
Syntheses of a,b-Unsaturated Carbonyl Compounds from the
Reactions of Monosubstituted Ozonides with
Stable Phosphonium Ylides
b
b
b
b
a
Yung-Son Hon,a,b, Ling Lu, Rong-Chi Chang, Sheng-Wun Lin, Pei-Pei Sun and Chia-Fu Lee
*
aDepartment of Chemistry, National Chung Cheng University, Chia-Yi, Taiwan 621, ROC
bInstitute of Chemistry, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
Received 21 August 2000; accepted 29 September 2000
AbstractÐOzonides derived from terminal alkenes reacted with 1.3 mol equiv. of stable phosphonium ylides to give (E)-a,b-unsaturated
carbonyl compounds in good to excellent yields. No reducing agent is needed in the reaction. However, alkoxyalkyl-substituted ozonides
afforded a mixture of (Z)- and (E)-a,b-unsaturated carbonyl compounds under similar condition. The E/Z isomeric ratio is affected by the
position of the heteroatom in the substituent of the ozonides. The possible mechanism of this reaction will be discussed. q 2000 Elsevier
Science Ltd. All rights reserved.
Introduction
will summarize the scope of this reaction and ®gure out its
possible reaction mechanism.
The ozonolysis of alkenes is an important technique in
organic synthesis.1 The intermediate was either ozonide or
a-alkoxy hydrogen peroxide dependent on the solvent used
in the reaction. Without isolation, they were usually reduced
directly to the corresponding carbonyls or alcohols.2 They
might also be oxidized to the corresponding carboxylic
acids.3 In our earlier communication, we have reported
that the reaction of monosubstituted ozonide with
1.3 mol equiv. of stable phosphonium ylide afforded the
(E)-a,b-unsaturated carbonyl compounds in excellent
yields.4 It is worthy to mention that no reducing agent was
needed in the reaction. In other words, this Wittig-type
reaction can be used ozonide instead of aldehyde as starting
material. Interestingly, we needed only 1.3 mol equiv. of the
stable phosphonium ylide to achieve the high yield reaction.
Apparently, the a,b-unsaturated carbonyl products were
formed by the Wittig reaction. However, we still need to
work out several puzzles in order to understand its reaction
mechanism. For example, we need to know: (1) why we
need only 1.3 mol equiv. of the stable phosphonium ylide;
(2) what the role of the stable phosphonium ylide is in the
reaction; (3) how the aldehyde is formed from the corre-
sponding ozonides without reducing agent. In this report, we
Results and Discussion
The ozonide formation and its reaction with phos-
phonium ylides
The terminal alkenes (i.e. the d,e-unsaturated ketones
1a±1e) were prepared from the corresponding conjugated
enone and allyltrimethylsilane in the presence of titanium
(IV) chloride according to the reported procedure.5 When
3-allylcyclohexan-1-one (1a) was carried out the ozonolysis
in CH2Cl2 at 2788C followed by the addition of excess
amount of methyl sul®de, the reaction was incomplete
even after 12 h stirring at rt. Presumably, the reduction of
this ozonide by methyl sul®de is sluggish. We did not wait
until the reaction completed and did not try to separate the
ozonide 2a and aldehyde 3a although they were separable.
The mixtures were reacted with 2 mol equiv. of
Ph3PvCHCO2Me (4a) at rt. We found that both the ozonide
2a and aldehyde 3a were consumed completely and the
corresponding (E)-a,b-unsaturated ester 5aa was isolated
in high yield. The yield is higher than that we estimated
from the aldehyde present in the reaction mixture. This
result indicated that both the aldehyde and ozonide have
reactivity with stable phosphonium ylide. In order to
prove this hypothesis, we prepared and isolated the ozonide
2a and found that it could react with Ph3PvCHCO2Me (4a)
(2 mol equiv.) at rt for 12 h to give compound 5aa in high
yield. At this stage, we understand that the ozonide has
reactivity with stable phosphonium ylide to give the Wittig
Keywords: ozonides; ozonolysis; stable phosphonium ylides; Wittig
reaction; ring fragmentation.
* Corresponding author. Department of Chemistry, National Chung Cheng
University, Chia-Yi, Taiwan 621, Republic of China. Tel.: 1886-5-
2720411 ext. 6262; fax: 1886-5-2721040;
e-mail: cheysh@ccunix.ccu.edu.tw
0040±4020/00/$ - see front matter q 2000 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)00903-0

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Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
Scheme 1. Phosphonium ylide: YˆCO2Me (4a), YˆCOPh (4b), YˆCOMe (4c), YˆCO2CH2Ph (4d), YˆCO2Bu-t (4e), YˆCHO (4f), YˆPh (4g).
reaction product. In order to investigate its optimal condi-
tions, we found that 1.3 mol equiv. of the stable phos-
phonium ylide were suf®cient to complete the reaction
and the product was isolated in 85% yield (Scheme 1;
Entry 1, Table 1). Intrigued by these two interesting obser-
vations, we started our work in the area of the ozonide
chemistry.6
followed by reaction with phosphonium ylide in the same
¯ask. The ozonide was generated at 2788C and phos-
phonium ylide was subsequently added to the solution,
which was then warmed up slowly to ambient temperature
(Pathway III, Scheme 1). The a,b-unsaturated carbonyl
compounds (i.e. 5da, 5db, 5ea and 5eb) were formed in
excellent yields by this one-¯ask process (Entries 7±10,
Table 1). In general, the yields from Pathway III are better
than those from Pathway II starting from alkenes 1 (Entries
7±10). The a,b-unsaturated carbonyl compounds tethered
with a keto group (Entries 1±10, Table 1) were useful
starting materials in the construction of the bridgehead
hydroxyl compounds stereoselectively induced by
samarium (II) iodide.8
In general, the mono-substituted ozonides were prepared
from terminal alkenes in CH2Cl2 at 2788C in excellent
yields and puri®ed by silica gel column chromatography.
They were stable in the freezer for more than 2 weeks and
decomposed slowly at room temperature.6a When the
ozonide 2a was treated with phosphonium ylide 4a
(1.3 mol equiv.) in CH2Cl2 at rt for 12 h, we obtained the
Wittig reaction product in high yield. However, we isolated
dimethyl fumarate (7) as byproduct in 2±3% yield. The
phosphonium ylide 4a was known to be oxidized by oxa-
ziridine to give compound 7.7 Therefore, the formation of
the minor product 7 was rationalized as follows. The
phosphonium ylide 4a was oxidized by ozonide 2a to give
methyl glyoxylate (6), which subsequently underwent
Wittig reaction with the remaining phosphonium ylide 4a
to give dimethyl fumarate (7) (Eq. (1)). Interestingly, this
side reaction could be avoided if the reaction was controlled
at 08C and then warmed slowly to room temperature. By
using this protocol, the ozonides reacted with 1.3 mol equiv.
of Ph3PvCHCO2Me (4a) to give (E)-a,b-unsaturated esters
in excellent yields (Pathway II of Scheme 1; Entries 1, 3, 5,
7 and 9, Table 1). The (E)-a,b-unsaturated ketones could
also be formed in modest to good yields from the corre-
sponding ozonides (Entries 2, 4, 6, 8 and 10). Interestingly,
for compounds 2a±2e, the phosphonium ylides could
chemoselectively react with the ozonide moieties in the
presence of keto groups (Entries 1±10).
In order to understand the scope of this newly developed
reaction. The ozonide 2f, derived from 4-phenyl-1-butene
(1f), was treated with several different kinds of phos-
phonium ylides (1.3 mol equiv.) at 2788C and then
warmed slowly to rt. We found that the reactions were
ef®cient
to
prepare
(E)-a,b-unsaturated
esters
(YˆCO2Me, CO2CH2Ph, CO2Bu-t) (Entries 11, 14, 15,
Table 1) and (E)-a,b-unsaturated ketones (YˆCOPh and
COMe) (Entries 12 and 13) in good yields. The progresses
of these reactions were monitored carefully by thin layer
chromatography. We found that the disappearance of the
ozonide 2f was concomitant with the formation of aldehyde
3f, which was then slowly consumed to give the Wittig
reaction product. In other words, the aldehyde 3g is
generated before proceeding the Wittig reaction.
Under the same conditions, Ph3PvCHCHO (4f)
(1.3 mol equiv.) reacted with ozonide 2f to give 3-phenyl-
propanal (3f) instead of (E)-unsaturated aldehyde 5ff. In
order to obtain the (E)-a,b-unsaturated aldehyde 5ff, the
reaction temperature should be raised to re¯ux in tetra-
hydrofuran for 12 h (Entry 16). This result indicated that
3-phenylpropanal was formed as the primary product before
Since the ozonide formation from terminal ole®ns was
excellent, it was feasible to carry out the ozonolysis
ꢀ1†

Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
9271
Table 1. Yields of the ozonide formations and their reaction with stable phosphonium ylides
Entry
RCHvCH2 Rˆ
trans-RCHvCHY Formation
Yield (%)
Pathway II, yield
(%) from ozonide
Pathway III, yield
(%) from alkene
1
2a 95
YˆCO2Me 5aa 85
±
2
3
YˆCOPh 5ab 55
YˆCO2Me 5ba 93
±
±
2b 90
4
5
YˆCOPh 5bb 72
YˆCO2Me 5ca 93
±
±
2c 92
6
7
YˆCOPh 5cb 62
YˆCO2Me 5da 92
±
2d 93
YˆCO2Me 5da 90
8
9
YˆCOPh 5db 65
YˆCO2Me 5ea 91
YˆCOPh 5db 64
YˆCO2Me 5ea 91
2e 93
10
11
12
13
14
15
16
17
YˆCOPh 5eb 67
YˆCOPh 5eb 67
YˆCO2Me 5fa 82
YˆCOPh 5fb 78
YˆCOMe 5fc 82
YˆCO2Bn 5fd 74
YˆCO2Bu-t 5fe 82
YˆCHO 5ff 84a
YˆPh 5fg 78b
PhCH2CH2± 1f
PhCH2CH2± 1f
PhCH2CH2± 1f
PhCH2CH2± 1f
PhCH2CH2± 1f
PhCH2CH2± 1f
PhCH2CH2± 1f
2f 94
±
±
±
±
±
±
±
a The reaction was carried out in re¯uxing THF for 12 h.
b The reaction was carried out in the presence of 2.2 mol equiv. of the ylide at 2788C and the E/Z ratio of compound 5fg was 5/2.
forming the Wittig product. When we used 1.3 mol equiv.
of Ph3PvCHPh (4g) to react with ozonide 2f, only
3-phenylpropanal (3f) was formed even though the reaction
temperature was heated to re¯ux in THF. In order to give the
Wittig reaction product 5fg (E/Zˆ5:2, 84% yield) in good
yield, 2.2 mol equiv. of the ylide 4g were needed (Entry 17,
Table 1). Apparently, in comparison with the stable ylide
(4a±4f), one extra mol equiv. of the semistable ylide 4g is
necessary to give the Wittig reaction product in high yield.
We will explain their difference in reactivity in the later part
of the paper.
Ph3PvCHCO2Me to give a mixture of the a,b-unsaturated
esters 5ga in 60% yield. The E/Z ratio is 1:1.1 (Entry 1,
Pathway III, Table 2). Since the a-alkoxyaldehyde 3g is
generated before proceeding the Wittig reaction and the
a-alkoxyaldehyde is known to react with stable phos-
phonium ylides to give a mixture of E- and Z-ole®ns.9
Under similar conditions, both 4-benzyloxy-1-butene (1h)
and 5-benzyloxy-1-pentene (1i) gave the Wittig product in
good yields and their E/Z ratio were 7.5:1 and 11:1, respec-
tively (Entries 3 and 5, Table 2). Results of entries 1, 3 and 5
indicate that the E/Z ratio of the a,b-unsaturated esters is
affected signi®cantly by the chain length of the methylene
unit between the benzyloxy group and the aldehyde. The
longer of the linking methylene chain, the more E-isomers
Interestingly, we found that the ozonide derived from 3-
benzyloxy-1-propene (1g) reacted with 1.3 mol equiv. of

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Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
Table 2. The E/Z ratio yields of the Wittig reaction from Pathway I and III
Entry
Alkene
RCHO Yield (%)
PhCH2O(CH2)nCHvCHCOY Formation
Pathway
I, yield
(%) (E/Z)
from
aldehyde
Pathway III,
yield (%)
(E/Z) from
alkene
1
2
3
4
5
6
7
8
PhCH2OCH2CHvCH2 1g
PhCH2OCH2CHvCH2 1g
PhCH2O(CH2)2CHvCH2 1h
PhCH2O(CH2)2CHvCH2 1h
PhCH2O(CH2)3CHvCH2 1i
PhCH2O(CH2)3CHvCH2 1i
Ph3COCH2CHvCH2 1j
3g 81
3h 86
3i 86
3j 72
YˆOMe 5ga
YˆMe 5gc
YˆOMe 5ha
YˆMe 5hc
YˆOMe 5ia
YˆMe 5ic
59 (4.1:1)
66 (10:1)
51 (10:1)
70 (22:1)
84 (17:1)
64 (1:0)
60 (1:1.1)
48 (8:1)
78 (7.5:1)
51 (27:1)
74 (11:1)
49 (1:0)
YˆOMe 5ja
YˆMe 5jc
62 (1.8:1)
63 (10:1)
60 (1.6:1)
68 (9:1)
Ph3COCH2CHvCH2 1j
were formed (Entries 1, 3 and 5). When a bulky triphenyl-
methoxy group replaced the benzyloxy, the E/Z ratio of the
a,b-unsaturated ester formations was changed from 1:1.1 to
1.6:1 (Entries 1 and 7). The E/Z ratio was determined by the
integration of the ole®nic proton of the a,b-unsaturated
carried out the reaction of the 1,1-disubstituted ozonide
with stable phosphonium ylide. Methallyl benzyl ether (8)
was converted to 1,1-disubstituted ozonide 9 by ozonolysis
in pentane at 2788C in 63% yield. The ozonide 9 was
isolated and treated with 1.3 mol equiv. of phosphonium
ylide 4a in CH2Cl2 at room temperature for 14 h to give
a-benzyloxyacetone (10) in 88% yield and benzyloxy-
methyl acetate (11) in 8% yield (Scheme 2). There is no
Wittig-type product formation here since ketone 10 is not
reactive with stable ylide.11 The minor product, benzyl-
oxymethyl acetate (11), might come from the Baeyer±
Villiger type rearrangement of the ozonide 9 as shown in
Scheme 2.12 The reaction mixture in Scheme 2 was chro-
matographed on a silica gel column. Compounds 10 and 11
were separated from the reaction mixture easily. The polar
component was then eluted out by a mixed solvents of 10%
MeOH in CH2Cl2 from silica gel column chromatography.
The polar component could be converted by aqueous
sodium hydroxide to give the phosphonium ylide 4a in
high yield. In other words, the structure of the polar compo-
nent in the reaction mixture should be the phosphonium
formate 4a0. Therefore, it is evident that the phosphonium
ylide can abstract the ozonide ring proton followed by ring
fragmentation to give the carbonyl compound 10 and phos-
phonium formate 4a0 (Scheme 2).
1
esters in their H NMR spectra. The E- and Z- isomers
were easily separated by silica gel column chromatography
and the Z-isomer was found to be the less polar one. As for
the a,b-unsaturated ketones formation, we also found
that the longer of the linking methylene chain, the more
E-isomers were formed (Entries 2, 4 and 8). Interestingly,
5-benzyloxy-1-pentene (1i) was converted to (E)-enone
(5ic) exclusively (Entry 6). In general, the E/Z ratio of the
a,b-unsaturated ketones is usually higher than those for the
a,b-unsaturated esters (Pathway III, Table 2). However, it is
not clear why the position of the heteroatom on the aldehyde
will affect the stereochemical outcome of the products.
In order to compare the result of the traditional Wittig reac-
tion (Pathway I) with our `one-¯ask' protocol (Pathway III),
the ozonolysis of the terminal ole®ns (1g±1j) followed by
reduction with Ph3P to give the aldehydes (3g±3j) in good
yields (Table 2). The aldehydes were then reacted with
1.2 mol equiv. of stable phosphonium ylides in CH2Cl2 at
room temperature to give the corresponding Wittig reaction
products in 12 h (Pathway I, Table 2). The results in Table 2
indicate that our `one-¯ask' process (Pathway III) give a
better yield in comparison with the traditional Wittig reac-
tion (Pathway I). In general, more Z isomer was formed
from Pathway III in comparison with those from Pathway
I (Table 2). The possible reason for their difference will be
discussed later.
(b) The reactivity of the phosphonium formate with alde-
hyde. Now we understand that the ozonide ring proton is
easily removed by the stable phosphonium ylide 4a to give
the aldehyde and phosphonium formate 4a0. However, it
needs only 1.3 mol equiv. of the ylide to react with ozonide
to give the Wittig reaction product in high yield. In other
words, most of ylide have been converted to the phos-
phonium formate 4a0 in the ®rst step. The phosphonium
formate 4a0 should have reactivity with aldehyde 3f. Other-
wise, we cannot explain why the Wittig reaction yield is
high (Pathways II and III, Scheme 1). However, it is
known that the phosphonium salt such as phosphonium
bromide 4b0 does not react with aldehyde. Therefore, we
have to prepare the phosphonium formate 4a0 and demon-
strate its reactivity with aldehyde.
The plausible mechanism for the Wittig reaction from
ozonides and phosphonium ylides
(a) Phosphonium ylide played as a base in its reaction
with ozonide. Our earlier study showed that the ozonide
ring protons were easily removed by weak base such as
triethylamine regioselectively to give the carbonyl
compounds.10 We have also described that the monosubsti-
tuted ozonides reacted with phosphonium ylide to give the
aldehydes as intermediates before proceeding the Wittig
reaction (Entry 16, Table 1). In order to have direct evidence
to support that the basicity of the stable phosphonium ylide
is strong enough to abstract the ozonide ring proton, we
The phosphonium formate 4a0 was prepared in excellent
yield by the addition of 1 mol equiv. of formic acid to the
phosphonium ylides 4a.13 Interestingly, the phosphonium
formate 4a0 can react with 3-phenylpropanal (3f) in

Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
9273
Scheme 2.
CH2Cl2 at room temperature in 0.5 h to give the Wittig
reaction product in excellent yield. Therefore, it is reason-
able to propose the mechanism of the reaction between
ozonide and ylide as follows. The ozonide ring proton was
removed regioselectively by the stable phosphonium ylides
4a. The ring fragmentation then occurred to give aldehyde
3f as well as phosphonium formate 4a0 as intermediates.
The phosphonium formate 4a0 subsequently reacted with
aldehyde 3f to give a,b-unsaturated carbonyl compound
5aa in good yield (Fig. 1).13
(JH±Cˆ133.6 Hz, JP±Cˆ56.5 Hz) in proton-coupled 13C
NMR spectrum (top one, Fig. 2). It means that the a-carbon
is coupled with the adjacent phosphorus and hydrogen
nuclei. The phosphonium formate 4a0 has excellent
reactivity with aldehyde and its a-carbon appears as a
doublet (JP±Cˆ56.5 Hz) at d 30.2 ppm in both proton-
coupled and proton-decoupled 13C NMR spectra (Fig. 2).
It means that the a-carbon is coupled with the adjacent
phosphorus but not with hydrogen nuclei. The absence of
the C±H coupling in compound 4a0 may be ascribed to the
rapid intramolecular proton exchange between the activated
methylene group and formate anion. On the other hand, the
presence of the C±H coupling (JH±Cˆ133.6 Hz) in
compound 4a00 indicates that C±H bond of the methylene
group does not exchange with bromide intramolecularly.
Since the formate is a stronger base than bromide, the rate
of the intramolecular proton exchange may be dependent on
the basicity of the counteranion.13 Therefore, the proton-
coupled 13C NMR splitting pattern of the a-carbon provides
a valuable information to predict the reactivity of the phos-
phonium salts. In other words, with the a-carbon splitting
pattern appeared as a doublet for the phosphonium salts,
excellent reactivity in the Wittig reaction is expected. On
We are interesting in understanding why the phosphonium
bromide 4a00 and phosphonium formate 4a0 are so different
in their reactivity with aldehyde. In order to answer this
question, both the proton-coupled and proton-decoupled
13C NMR spectra of the phosphonium bromide 4a00 and
phosphonium formate 4a0 were taken and their partial
spectra was shown in Fig. 2.
The phosphonium bromide 4a00 has no reactivity with
aldehyde and its a-carbon appears at d 31.7 ppm as a
doublet (JP±Cˆ56.5 Hz) in proton-decoupled 13C NMR
spectrum (bottom one, Fig. 2); a triplet of doublet
Figure 1. The possible mechanism for the formation of compound 5aa from the reaction of ozonide 2f and stable phosphonium ylide 4a.

9274
Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
Figure 2. The characteristic 13C NMR signals for the phosphonium formate 4a0 and bromide 4a00. (A: Proton-coupled; B: Proton-decoupled).
the other hand, with the a-carbon splitting patterns appeared
as the triplet of doublet for those phosphonium salts, poor
reactivity in Wittig reaction is expected.13
Conclusions
The newly developed method is ef®cient for the preparation
of a,b-unsaturated esters and ketones from the reaction of
mono-substituted ozonides and stable phosphonium ylides.
The yields were excellent for the ester formation and were
modest to good for the ketone formation. Only (E)-isomers
were formed if the substituents containing no heteroatom.
However, alkoxyalkyl-substituted ozonides afforded a
mixture of (Z)- and (E)-a,b-unsaturated carbonyls and the
E/Z isomeric ratio is affected by the position of the hetero-
atom in the substituent of the ozonides. For the stable phos-
phonium ylides, it only needed 1.3 mol equiv. to complete
the reaction. For the semistable phosphonium ylides 4g,
however, it needed 2.2 mol equiv. to complete the reaction
at low temperature. In general, the yields of the one-¯ask
reactions (Pathway III) were higher than those from the
corresponding two-step process (Pathway II). Our one-
¯ask protocol (Pathway III) is more ef®cient than the
traditional Wittig reaction (Pathway I).
The a-methylene group of the phosphonium formate 4a0 is
quite acidic so that the intramolecular proton exchange rate
between the a-methylene group and formate is too fast to be
differentiated by NMR. This exchange process gives a tran-
sient intermediate (i.e. ylide and formic acid) which can
subsequently undergo Wittig reaction with aldehyde
(Fig. 1). The formic acid formed in the transient inter-
mediate serves as a catalyst to accelerate the Wittig reaction
(Fig. 1). Therefore, the reaction rate of the phosphonium
acetate with aldehyde should be faster than the reaction
involving the phosphonium ylide only.14
We have described that 2.2 mol equiv. of the semistable
ylide 4g were needed to react with ozonide 2f to give
78% yield of the Wittig reaction product (Entry 17, Table
1). The reaction of the ozonide 2f with semistable phos-
phonium ylide 4g should give aldehyde 3f and triphenyl-
benzylphosphonium formate (Ph3P1CH2Ph HCO22, 4g0)
according to proposed mechanism in Fig. 1. The methylene
group of the phosphonium formate 4g0 should not be acidic
enough to exchange with its counteranion (i.e. formate)
effectively because the phenyl group is not an effective
electron-withdrawing group. The regeneration of the phos-
phonium ylide 4g as the transient intermediate via proton
exchange process is not possible. Therefore, one more
equiv. of the phosphonium ylide 4g was required to
consume the aldehyde 3f.
Experimental
All reactions were carried out under nitrogen. Unless other-
wise noted, materials were obtained from commercial
suppliers and used without further puri®cation. Melting
points were determined by using a Yanaco micro melting
point apparatus and were uncorrected. The 1H and 13C NMR
spectra were recorded on a Bruker AC 200 and Bruker
Avance APX-400 spectrometer, and chemical shifts were
given in ppm down®eld from tetramethylsilane (TMS). IR
spectra were taken with a Perkin±Elmer 883 spectro-
photometer and only noteworthy absorptions were listed.
Mass spectra were measured on a VG 70-250S spectrometer
by electronic impact at 70 eV (unless otherwise indicated).
High Resolution Mass Spectroscopy (HRMS) was
measured on a JEOL JMS-HX 110 (National Hsing-Hua
University) or VG-11-250J (Academia Sinica) Mass
Spectrometer. The elemental analyses were measured on
Heraeus NCH-RAPID and Perkin±Elmer 2400 CHN
analyzer.
We have also described that more Z isomers were formed
from Pathway III in comparison with those from traditional
Wittig reaction (i.e. Pathway I) (Table 2). There are several
factors to control the isomeric ratio. For example, the E/Z
ratio of compound 5ha formation from Pathway I was
reported from 98:2 to 9.1:1 by simply changing the reaction
temperature and solvent.15 According to the proposed
mechanism in Fig. 1, 1 mol equiv. of the formic acid was
formed in Pathway III. The presence of the formic acid in
the reaction mixture is possibly responsible for the
difference of the E/Z ratio between these two pathways.

Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
9275
General procedure for the ozonolysis of terminal alkenes
General procedure for the reaction of the triphenyl-
phosphonium formate 4a0 with aldehyde 3f
In a 25 mL of two-neck ¯ask, equipped with a magnetic
stirrer, a drying tube and a gas dispersing tube (with porous
fritted tip), were placed 15 mL of CH2Cl2 and 3-allyl-
alkanone 1d (423.4 mg, 3.0 mmol). A stream of ozone
was bubbled through the solution at 2788C. Ozone treat-
ment was terminated when the mixtures assumed a blue
color. A stream of nitrogen was used to remove excess
ozone. The mixtures were then allowed to warm up to
room temperature. It was concentrated and chromato-
graphed on a silica gel column by elution with EtOAc/
hexane (1/20) to give ozonide 2d (527.7 mg, 93% yield)
as a colorless oil.
To a stirring solution of the triphenylphosphonium formate
4a0 (879.8 mg, 2.31 mmol) in 5 mL of anhydrous CH2Cl2
was added aldehyde 3f (278.9 mg, 2.08 mmol) at room
temperature under nitrogen. The reaction mixture was stir-
red for 30 min and was concentrated. The residue was
puri®ed by silica gel column chromatography to give
(E)-a,b-unsaturated ester 5fa in 92% yield.
4-(3-Oxocyclohexyl)-2(E)-butenoic acid methyl ester
(5aa). Colorless oil; H NMR (CDCl3) d 1.25±2.42 (m,
1
11H), 3.74 (s, 3H, OMe), 5.85 (dt, Jˆ15.5, 1.8 Hz,
CvCHCO), 6.90 (dt, Jˆ15.5, 7.7 Hz, 1H, CHˆCHCO);
13C NMR (CDCl3) d 24.79, 30.72, 38.06, 38.77, 41.08,
47.54, 51.34 (OCH3), 122.91 (CvC±CO), 145.86 (CvC±
CO), 166.50 (CvO), 210.55 (CvO); IR (CH2Cl2): 1714
(CvO), 1654, 1437, 1317, 1270, 1203, 986 cm21; MS
(m/z): 196 (M1, 3), 165 (10), 120 (16), 97 (100), 91 (33),
69 (56), 55 (32), 41 (51); HRMS Calcd for C11H16O3 m/z
196.1099, found: 196.1088.
General procedure for the reaction of ozonide with
phosphonium ylide
To a solution of ozonide 2d (378.3 mg, 2 mmol) in 10 mL of
CH2Cl2 was added Ph3PvCHCO2Me (4a) (869.3 mg,
2.6 mmol) at 08C and the reaction was warmed slowly to
ambient temperature. After 12 h, the reaction mixture was
concentrated and chromatographed on a silica gel column
by elution with EtOAc/hexane (1/8) to give (E)-methyl ester
5da (364.8 mg, 92% yield) as a colorless oil.
4-(3-Oxocyclopentyl)-2(E)-butenoic acid methyl ester
(5ba). Colorless oil; H NMR (CDCl3) d 1.45±2.44 (m,
1
9H), 3.74 (s, 3H, OCH3), 5.87 (dt, Jˆ15.6, 1.9 Hz, 1H,
CvCHCO), 6.93 (dt, Jˆ15.6, 7.7 Hz, 1H, CHˆCHCO);
13C NMR (CDCl3) d 28.89, 35.84, 37.60, 37.98, 44.34,
51.33, 122.49 (CvCCO), 148.20 (CvC±CO), 168.53,
218.04 (CvO); IR (CH2Cl2): 2956, 1737 (CvO), 1653,
1553, 1525, 1400 cm21; MS (m/z): 183 (M111, 18), 182
(M1, 18), 151 (32), 150 (31), 122 (11), 100 (35), 96 (64), 83
(100), 55 (28); HRMS Calcd for C10H14O3 m/z 182.0943,
found: 182.0941.
General procedure for the sequential ozonolysis and
Wittig-type reactions
In an 100 mL of two-neck ¯ask, equipped with a magnetic
stirrer, a drying tube and a gas dispersing tube (with porous
fritted tip), were placed 30 mL of CH2Cl2 and 3-allyl-
alkanone 1d (807 mg, 5.76 mmol). A stream of ozone was
bubbled through the solution at 2788C. Ozone treatment
was terminated when the mixtures assumed a blue color.
A stream of nitrogen removed excess ozone. A solution of
Ph3PvCHCO2Me (4a) (2502.9 mg, 7.49 mmol) in 15 mL
of CH2Cl2 was added to the solution. The reaction was
warmed slowly to room temperature and stirred for 12 h.
The reaction mixture was concentrated and chromato-
graphed on a silica gel column by elution with EtOAc/
hexane (1/8) to give (E)-methyl ester 5da (1027.8 mg,
90% yield) as a colorless oil.
8a-(3-Methoxycarbonyl-2(E)-propenyl)-4a-methylocta-
hydronaphthalen-2-one (5ca). Colorless oil; 1H NMR
(CDCl3) d 1.38±2.60 (m, 17 H), 3.73 (s, 3H, OCH3), 5.87
(dt, Jˆ15.5, 1.7 Hz, 1H, CvCHCO), 6.94 (dt, Jˆ15.5,
7.6 Hz, 1H, CHˆCHCO); 13C NMR (CDCl3) d 21.53,
24.20, 26.78, 27.59, 34.02, 37.69, 41.83, 47.49, 51.33
(OCH3), 124.15 (CvCHCO), 144.01 (CvCHCO), 166.39
(CvO), 211.92 (CvO); IR (CH2Cl2): 1706, 1652, 1442,
1274 cm21; MS (m/z): 250 (M1, 2), 219 (12), 191 (3), 151
(100), 133 (52), 109 (33), 100 (68), 91 (27), 81 (41), 67 (40);
HRMS Calcd for C15H22O3 m/z 250.1569, found: 250.1567.
Methoxycarbonylmethyltriphenylphosphonium formate
(4a0). To a stirring solution of the Ph3PvCHCO2Me (4a)
(403.3 mg, 1.21 mmol) in 4 mL of anhydrous CH2Cl2 was
added a solution of formic acid (55.5 mg, 1.21 mmol) in
1 mL of anhydrous CH2Cl2 at rt under nitrogen. The
reaction mixture was stirred for 5 min and concentrated in
vacuo to give 440 mg of phosphonium formate 4a0 as a
white solid in 96% yield. mp 136±1388C; 1H NMR
(CDCl3) d 3.51 (s, 3H, OCH3), 5.18 (s, 2H, ±CH2±),
7.50±7.73 (m, 15H, aromatic-H); 13C NMR (CDCl3) d
5,5-Dimethyl-7-oxo-2(E)-octenoic acid methyl ester
(5da). Colorless oil; 1H NMR (CDCl3) d 1.03 (s, 6H,
C(CH3)2), 2.11 (s, 3H, CH3CO), 2.26 (dd, Jˆ8.0, 1.3 Hz,
2H, CH2±CvC), 2.34 (s, 2H, CH2CO), 3.73 (s, 3H, OCH3),
5.84 (dt, Jˆ16.7, 1.4 Hz, 1H, CvCHCO), 6.95 (dt, Jˆ16.7,
8.0 Hz, 1H, CHvC±CO); 13C NMR (CDCl3) d 27.23,
32.15, 33.83, 44.01, 51.29, 53.05, 123.42 (CvC±CvO),
145.84 (CvC±CvO), 166.65 (CvO), 207.94 (CvO); IR
(CH2Cl2): 2955, 1720, 1652, 1588, 1433 cm21; MS (m/z):
198 (M1, 4), 183 (7), 166 (8), 141 (28), 125 (16), 109 (31),
100 (64), 81 (32), 43 (100); HRMS Calcd for C11H18O3 m/z
198.1256, found: 198.1254.
1
1
30.1 (d, JP±Cˆ110.6 Hz), 50.4, 125.4 (d, JP±Cˆ91.0 Hz),
3
128.5, 128.9 (d, JP±Cˆ12.4 Hz), 132.5, 132.9 (d,
2JP±Cˆ9.9 Hz), 166.5, 170.1 (d, JP±Cˆ8.5 Hz); IR (KBr)
1742, 1613, 1438 cm21; MS m/z (relative intensity):
334 (M12HCO2H, 25), 277 (57), 152 (100); Anal.
Cacld for C22H21O4P: C, 69.47; H, 5.56. Found: C, 69.49;
H, 5.70.
7-Oxo-2(E)-octenoic acid methyl ester (5ea). Colorless
1
oil; H NMR (CDCl3) d 1.75 (quin, Jˆ7.2 Hz, 2H), 2.11
(s, 3H), 2.18 (q, Jˆ7.2 Hz, 2H), 2.42 (t, Jˆ7.2 Hz, 2H), 3.69

9276
Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
(s, 3H), 5.80 (dt, Jˆ15.6, 1.5 Hz, 1H), 6.89 (dt, Jˆ15.6,
7.2 Hz, 1H); 13C NMR (CDCl3) d 21.76, 29.85, 31.21,
42.43, 51.32 (OCH3), 121.52, 148.23, 166.81 (CvO),
207.93 (CvO); IR (CH2Cl2): 2952, 1716, 1656, 1433,
1258 cm21; MS (m/z): 170 (M1, 3), 138 (98), 113 (100),
110 (21), 100 (56), 95 (50), 93 (16), 81 (71), 68 (20), 58
(45); HRMS Calcd for C9H14O3 m/z 170.0943, found:
170.0925.
CH2), 2.20 (s, 3H, CH3CvO), 2.40 (q, Jˆ7.2 Hz, 2H,
CH2±CvO), 2.55 (t, Jˆ7.3 Hz, 2H, CH2±CvO), 6.93 (d,
Jˆ14.5 Hz, 1H, CvCHCOPh), 7.02±7.61 (m, 5H, ole®nic
and aromatic-H), 7.94±7.99 (m, 2H, aromatic-H); 13C NMR
(CDCl3) d 21.87, 29.80, 31.74, 42.47, 126.31 (CvCHCO),
128.35, 132.53, 137.66, 148.35 (CvC±CvO), 190.51,
207.96 (CvO); IR (CH2Cl2): 1707, 1668, 1620, 1447,
1356, 1291, 1179, 1017 cm21; MS (m/z): 216 (M1, 30),
198 (21), 173 (10), 159 (72), 146 (38), 120 (22), 105
(100), 91 (31), 77 (70); HRMS Calcd for C14H16O2 m/z
216.1151, found: 216.1148.
3-(4-Oxo-4-phenyl-2(E)-butenyl)cyclohexanone (5ab).
White solid, mp 55±568C; H NMR (CDCl3) d 1.35±2.55
1
(m, 11H), 6.86±7.08 (m, 2H, CHvCH), 7.44±7.61 (m, 3H,
aromatic-H), 7.91±7.95 (m, 2H, aromatic-H); 13C NMR
(CDCl3) d 24.80, 30.80, 38.20, 39.37, 41.12, 47.66,
127.72, 128.39, 128.44, 132.67, 138.22, 145.95 (CvC±
CO), 190.21 (CvO), 210.61 (CvO); IR (CH2Cl2): 3055,
2940, 1705, 1667, 1621, 1252, 730 cm21; MS (m/z): 242
(M1, 10), 224 (6), 180 (7), 157 (10), 146 (80), 145 (32),
137 (12), 131 (11), 123 (14), 120 (23), 115 (14), 110 (65),
105 (100), 97 (24), 91 (13), 77 (75), 69 (68), 67 (11), 55
(54), 41 (90); HRMS Calcd for C16H18O2 m/z 242.1307,
found: 242.1310.
5-Phenyl-2(E)-pentenoic acid methyl ester (5fa). Color-
less oil; H NMR (CDCl3) d 2.50±2.58 (m, 2H), 2.78 (t,
1
Jˆ7.4 Hz, 2H), 3.72 (s, 3H), 5.85 (dt, Jˆ15.6, 1.6 Hz, 1H),
7.17±7.33 (m, 5H, aromatic-H); 13C NMR (CDCl3) d 33.84,
34.31, 51.39 (OCH3), 121.44 (CHvCHCO), 126.15,
128.30, 128.45, 140.71, 148.31 (CHvCHCO), 166.97
(CvO); IR (CH2Cl2): 2949, 1717, 1653, 1431, 1316,
1256 cm21; MS (m/z): 190 (M1, 8), 159 (7), 158 (8), 130
(15), 91 (100), 65 (9); HRMS Calcd for C12H14O2 m/z
190.0994, found: 190.0997.
3-(4-Oxo-4-phenyl-2(E)-butenyl)cyclopentanone (5bb).
Pale yellow oil; H NMR (CDCl3) d 1.63±2.47 (m, 9H),
1,5-Diphenyl-2(E)-penten-1-one (5fb). Pale yellow oil; 1H
NMR (CDCl3) d 2.58±2.68 (m, 2H), 2.70±3.00 (m, 2H),
6.85 (d, Jˆ14.2 Hz, 1H), 7.00±7.12 (m, 1H), 7.12±7.44 (m,
5H), 7.45 (m, 3H), 7.86±7.90 (m, 2H); 13C NMR (CDCl3) d
34.43, 126.13, 126.52, 128.45, 132.57 (CvCHCO), 140.75,
148.34 (CH2CHvCH), 190.79 (CvO); IR (CH2Cl2): 3052,
2985, 1702, 1647, 1603, 1419, 1275, 1213 cm21; MS (m/z)
(60 eV): 236 (M1, 10), 116 (20), 105 (33), 91 (100), 77 (18);
HRMS Calcd for C17H16O m/z 236.1201, found: 236.1206.
1
6.89±7.08 (m, 2H, CHvCH), 7.43±7.61 (m, 3H,
aromatic-H), 7.90±7.95 (m, 2H, aromatic-H); 13C NMR
(CDCl3) d 28.99, 35.98, 38.00, 28.20, 44.43, 127.16
(CvC±CO), 128.32, 128.41, 132.66 (CvC±CO), 137.54,
146.23 (CvC±CO), 190.18 (CvO), 218.06 (CvO); IR
(CH2Cl2): 3061, 1737, 1673, 1616, 1445, 1403 cm21; MS
(m/z): 228 (M1), 185, 146, 122, 105 (100), 97, 83, 77, 69,
55; HRMS Calcd for C15H16O2 m/z 228.1151, found:
228.1150.
6-Phenyl-3(E)-hexen-2-one (5fc). Pale yellow oil; 1H
NMR (CDCl3) d 2.22 (s, 3H, Me), 2.48±2.61 (m, 2H),
2.79 (t, Jˆ6.9 Hz, 2H), 6.09 (dt, Jˆ16.0, 1.4 Hz, 1H),
6.82 (dt, Jˆ16.0, 6.6 Hz, 1H), 7.15±7.30 (m, 5H,
aromatic-H); 13C NMR (CDCl3) d 26.67 (CH3CO), 33.88,
34.21, 126.03, 128.13, 128.31, 131.51 (CHvCHCO),
140.46, 140.84 (CH2CHvC), 198.26 (CvO); IR
(CH2Cl2): 3029, 1664, 1623, 1356, 1313, 1246,
1184 cm21; MS (m/z) (60 eV): 174 (M1, 5), 159 (5), 131
(7), 116 (18), 91 (100); HRMS Calcd for C12H14O m/z
174.1045, found: 174.1047.
8a-(4-Phenyl-4-oxo-2(E)-butenyl)-4a-methyloctahydro-
naphthalen-2-one (5cb). Pale yellow oil; 1H NMR (CDCl3)
d 1.43±2.42 (m, 17H), 6.89±7.27 (m, 2H, CHˆCH), 7.43±
7.61 (m, 3H, aromatic-H), 7.93±8.22 (m, 2H, aromatic-H);
13C NMR (CDCl3) d 21.51, 24.32, 26.79, 27.59, 34.26,
37.61, 37.78, 42.24, 42.46, 47.25, 128.41, 128.89, 132.66,
137.58, 143.97, 189.80 (CvO), 212.17 (CvO); IR
(CH2Cl2): 3056, 1714, 1668, 1618, 1447, 1283,
1233 cm21; MS (m/z): 296 (M1, 28), 278 (10), 191 (10),
177 (9), 151 (38), 122 (42), 105 (100), 84 (80), 69 (15);
HRMS Calcd for C20H24O2 m/z 296.1777, found:
296.1775.
5-Phenyl-2(E)-pentenoic acid benzyl ester (5fd). Color-
less oil; H NMR (CDCl3) d 2.43±2.54 (m, 2H), 2.74 (t,
1
Jˆ8.2 Hz, 2H, CH2Ph), 5.15 (s, 2H, OCH2Ph), 5.88 (dt,
Jˆ15.7, 1.5 Hz, 1H), 7.04 (dt, Jˆ15.7, 6.7 Hz, 1H), 7.12±
7.36 (m, 10H, aromatic-H); 13C NMR (CDCl3) d 33.80,
34.16, 65.90 (OCH2Ph), 121.41 (CHvCHCO), 126.06,
128.03, 128.19, 128.38, 136.02, 140.61, 148.62
(CH2CHvCH), 166.17 (CvO); IR (CH2Cl2): 3033, 2943,
1715, 1650, 1308, 1250, 1168 cm21; MS (m/z) (33 eV): 266
(M1, 2), 181 (10), 175 (22), 159 (12), 91 (100), 65 (10);
HRMS Calcd for C18H18O2 m/z 266.1307, found:
266.1305.
5,5-Dimethyl-1-phenyl-2(E)-octen-1,7-dione (5db). Pale
yellow oil; H NMR (CDCl3) d 1.08 (s, 6H, C(CH3)2),
1
2.12 (s, 3H, CH3CO), 2.39 (s, 2H, CH2CO), 2.49
(d, Jˆ7.6 Hz, 2H, CH2±CvC), 6.92 (d, Jˆ15.4 Hz,
2H, CvCHCOPh), 7.04 (sextet, Jˆ7.6 Hz, 1H,
±CHˆCHCOPh), 7.40±7.60 (m, 3H, aromatic-H), 7.90±
7.98 (m, 2H, aromatic-H); 13C NMR (CDCl3) d 27.47,
32.18, 34.12, 44.53, 53.16, 128.42, 132.63, 145.96
(CvCHCO), 190.21, 208.02 (CvO); IR (CH2Cl2): 3059,
1712, 1667 cm21; MS (m/z): 244 (M1, 12), 187 (100), 171
(72), 146 (90), 145 (43), 131 (15), 105 (68), 91 (10), 77 (23);
HRMS Calcd for C16H20O2 m/z 244.1464, found: 244.1465.
5-Phenyl-2(E)-pentenoic acid tert-butyl ester (5fe).
Colorless oil; H NMR (CDCl3) d 1.48 (s, 9H, OCMe3),
1
2.42±2.54 (m, 2H), 2.76 (m, 2H, CH2Ph), 5.78 (dt,
Jˆ15.7, 1.6 Hz, 1H, CvCHCO), 6.90 (dt, Jˆ15.7, 6.7 Hz,
1H, CHvCHCO), 7.10±7.33 (m, 5H, aromatic-H); 13C
1
1-Phenyl-2(E)-octen-1,7-dione (5eb). Pale yellow oil; H
NMR (CDCl3) d 1.86 (quint, Jˆ7.2 Hz, 2H, CH2±CH2±

Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
9277
NMR (CDCl3) d 28.14, 33.78, 34.43, 80.08 (OCMe3),
123.50 (CHvCHCO), 126.10, 128.30, 128.44, 140.97,
146.74 (CvCHCO), 165.96 (CvO); IR (CH2Cl2): 3029,
3004, 2977, 1701, 1648, 1365, 1297, 1114 cm21; MS (m/
z) (40 eV): 176 (M12C4H8, 18), 159 (18), 130 (12), 91
(100), 65 (8); HRMS Calcd for C11H12O2 m/z 176.0837,
found: 176.0833.
(CvO), 1437, 1286, 1117, 1105, 1044, 724 cm21; MS
(m/z): 206 (M1, 5), 175 (18), 161 (20), 146 (21), 135 (40),
117 (20), 100 (30), 91 (100), 84 (20), 71 (18); HRMS Calcd
for C12H14O3 m/z 206.0943, found: 206.0944.
(Z)-4-Benzyloxycrotonic acid methyl ester (5ga-Z).
Colorless oil; H NMR (CDCl3) d 3.70 (s, 3H, OCH3),
1
4.55 (s, 2H) 4.65 (dd, Jˆ4.9, 2.3 Hz, 2H), 5.83 (dt,
Jˆ11.7, 2.3 Hz, 1H), 6.45 (dt, Jˆ11.7, 4.9 Hz, 1H), 7.25±
7.36 (m, 5H, aromatic-H); 13C NMR (CDCl3) d 51.25,
68.40, 72.84, 119.04, 127.72, 128.38, 137.86, 148.50,
166.36 (CvO); IR (CH2Cl2): 3031, 1719, 1641, 1436,
1202, 1092, 724 cm21; MS (m/z): 206 (M1, 5), 164 (35),
149 (45), 135 (100), 115 (32), 100 (70), 91 (77), 83 (32), 77
(30), 71 (20), 65 (30); HRMS Calcd for C12H14O3 m/z
206.0943, found: 206.0958.
5-Phenyl-2(E)-pentenal (5ff). Colorless oil; 1H NMR
(CDCl3) d 2.67 (q, Jˆ6.3 Hz, 2H), 2.84 (t, Jˆ8.5 Hz,
2H), 6.13 (dd, Jˆ15.5, 7.9 Hz, 1H), 6.86 (dt, Jˆ15.6,
6.3 Hz, 1H), 9.49 (d, Jˆ7.9 Hz, 1H); 13C NMR (CDCl3) d
34.17, 126.34, 128.28, 128.55, 133.37, 140.22, 157.21,
193.89; IR (CH2Cl2): 3063, 3030, 2931, 1686, 1490,
1121 cm21; Mass (m/z) (50 eV): 160 (M1, 8), 142 (5), 116
(20), 91 (100), 77 (6), 65 (16); HRMS Calcd for C17H16O
m/z 160.0888, found: 160.0895.
5-Benzyloxy-2(E)-pentenoic acid methyl ester (5ha-E).
Colorless oil; 1H NMR (CDCl3) d 2.48 (qd, Jˆ6.5,
1.4 Hz, 2H), 3.58 (t, Jˆ6.5 Hz, 2H), 3.72 (s, 3H), 4.52 (s,
2H), 5.90 (dt, Jˆ15.7, 1.5 Hz, 1H), 6.99 (dt, Jˆ15.7, 6.9 Hz,
1H), 7.29±7.39 (m, 5H, aromatic-H); IR (CH2Cl2): 3033,
1716 (CvO), 1652, 1436, 1320, 1274, 1179, 1106, 1034,
978, 741, 703 cm21; MS (m/z): 220 (M1, 2), 190 (3), 176
(3), 160 (17), 145 (4), 130 (8), 122 (18), 144 (21) 105 (20),
100 (79), 91 (100), 77 (6), 69 (28); HRMS Calcd for
C13H16O3 m/z 220.1099, found: 220.1109.
1,4-Diphenyl-1-butene (5fg-E and 5fg-Z). Benzylidene-
triphenylphosphorane (Ph3PvCHPh) was prepared from
the reaction of benzyltriphenylphosphonium bromide
(4289.9 mg, 9.9 mmol) and n-BuLi (6.2 mL, 1.6 M in
hexane) in 20 mL of THF at 2788C for 0.5 h. To a solution
of ozonide 2f, prepared from 4-phenyl-1-butene (1f)
(633.6 mg, 4.8 mmol), in 10 mL of THF was added the
THF solution of Ph3PvCHPh at 2788C and the reaction
was warmed slowly to ambient temperature. After 3 h, the
reaction mixture was concentrated and chromatographed on
a silica gel by elution with hexane to give a mixture of E-and
Z-ole®n 5fg (731.2 mg, 78% yield) as a colorless oil. The
E/Z ratio is approximately 5/2 and the Z-isomer is less polar
than E-isomer on TLC. Preparative TLC separated them
with hexane as a developing solvent.
5-Benzyloxy-2(Z)-pentenoic acid methyl ester (5ha-Z).
Colorless oil; 1H NMR (CDCl3) d 2.99 (qd, Jˆ6.3,
1.8 Hz, 2H), 3.60 (t, Jˆ6.3 Hz, 2H), 3.71 (s, 3H), 4.53 (s,
2H), 5.86 (dt, Jˆ11.5, 1.8 Hz, 1H), 6.35 (dt, Jˆ11.5, 3.6 Hz,
1H), 7.30±7.36 (m, 5H, aromatic-H); 13C NMR (CDCl3) d
29.55, 50.97, 68.98, 72.77, 120.56, 127.56, 128.31, 138.29,
147.05, 183.92 (CvO); IR (CH2Cl2): 2947, 1717 (CvO),
1652, 1439, 1322, 1273, 1179, 1104, 1034, 978, 740,
703 cm21; MS (m/z) (15 eV): 221 (M111, 3), 188 (35),
176 (18), 160 (76), 146 (23), 130 (36), 114 (98), 100 (56),
91 (100); HRMS Calcd for C13H16O3 m/z 220.1099, found:
220.1084.
1,4-Diphenyl-1(E)-butene (5fg-E). White solid, mp 31.5±
32.58C; H NMR (CDCl3) d 2.47±2.56 (m, 2H), 2.79 (t,
1
Jˆ7.2 Hz, 2H) 6.24 (dt, Jˆ16.0, 6.6 Hz, 1H, ±CHvCHPh),
6.41 (d, Jˆ16.0 Hz, 1H, ±CHvCHPh), 7.16±7.33 (m, 10H,
aromatic-H); 13C NMR (CDCl3) d 34.83, 35.86, 125.86,
125.97, 126.90, 128.34, 128.45, 129.94, 130.37,137.72,
141.73; IR (CH2CL2): 3082, 3060, 3025, 2929, 2855,
1598, 1488, 1446 cm21; MS (m/z): 208 (M1, 25), 117
(100), 91 (28), 77 (8) 65 (7); HRMS Calcd for C16H16 m/z
208.1253, found: 208.1252.
6-Benzyloxy-2(E)-hexenoic acid methyl ester (5ia-E).
1
Colorless oil; H NMR (CDCl3) d 1.73 (quint, Jˆ7.0 Hz,
2H), 2.30 (qd, Jˆ7.0, 1.4 Hz, 2H), 3.48 (t, Jˆ7.0 Hz, 2H),
3.71 (s, 3H), 4.49 (s, 2H, CH2Ph), 5.83 (dt, Jˆ15.7, 1.4 Hz,
1H), 6.97 (dt, Jˆ15.7, 7.0 Hz, 1H), 7.25±7.47 (m, 5H,
aromatic-H); 13C NMR (CDCl3) d 28.08, 28.89, 51.35,
69.17, 72.91, 121.18, 127.56, 128.34, 148.89, 167.05
(CvO); IR (CH2Cl2): 3027, 2940, 1704 (CvO), 1647,
1430, 1262, 1201, 1086, 1038, 974, 733 cm21; MS (m/z):
234 (M1, 2), 220 (2), 202 (2), 188 (5), 174 (5), 160 (38), 145
(10), 130 (18), 121 (10), 114 (60), 100 (10), 91 (100);
HRMS Calcd for C14H18O3 m/z 234.1256, found: 234.1243.
1
1,4-Diphenyl-1(Z)-butene (5fg-Z). Colorless oil; H NMR
(CDCl3) d 2.61±2.68 (m, 2H), 2.74±2.81 (m, 2H), 5.69 (dt
Jˆ11.6, 6.7 Hz, 1H, ±CHvCHPh), 6.43 (d, Jˆ11.6 Hz,
1H, ±CHvCHPh), 7.15±7.49 (m, 10H, aromatic-H); 13C
NMR (CDCl3) d 30.40, 36.07, 125.91, 126.56, 128.14,
128.34, 128.46, 128.71, 129.43, 131.80, 137.57, 141.67;
IR (CH2Cl2): 3080, 3060, 3024, 2924, 2855, 1599, 1490,
1445, 1073, 1026, 962 cm21; MS (m/z): 208 (M1, 20),
180 (10), 117 (100), 91 (28), 77 (6), 65 (8); HRMS Calcd
for C16H16 m/z 208.1253, found: 208.1252.
6-Benzyloxy-2(Z)-hexenoic acid methyl ester (5ia-Z).
1
Colorless oil; H NMR (CDCl3) d 1.78 (quint, Jˆ6.6 Hz,
(E)-4-Benzyloxycrotonic acid methyl ester (5ga-E).
Colorless oil; H NMR (CDCl3) d 3.75 (s, 3H, OCH3),
2H), 2.75 (qd, Jˆ6.6, 1.7 Hz, 2H), 3.51 (t, Jˆ6.6 Hz, 2H),
3.70 (s, 3H), 4.50 (s, 2H), 5.79 (dt, Jˆ11.5, 1.7 Hz, 1H,
CvCH±CO), 6.26 (dt, Jˆ11.5, 6.6 Hz, 1H, CHvCH±
CO), 7.28±7.35 (m, 5H, aromatic-H); 13C NMR (CDCl3)
d 25.91, 29.11, 50.98, 69.78, 72.93, 119.56, 127.50,
127.61, 128.32, 138.49, 150.02, 166.76 (CvO); IR
(CH2Cl2): 2937, 1705 (CvO), 1645, 1432, 1261, 1205,
1
4.18 (dd, Jˆ4.2, 2.1 Hz, 2H), 4.57 (s, 2H, Ph±CH2), 6.15
(dt, Jˆ15.7, 2.1 Hz, 1H), 7.00 (dt, Jˆ15.7, 4.2 Hz, 1H),
7.29±7.37 (m, 5H, aromatic-H); 13C NMR (CDCl3) d
51.50, 68.47, 72.66, 120.82, 127.54, 127.74, 128.38,
137.60, 144.48, 166.66 (CvO); IR (CH2Cl2):3032, 1721

9278
Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
1
7-Benzyloxy-3(E)-hepten-2-one (5ic-E). Colorless oil; H
1086, 1038, 974 cm21; MS (m/z): 234 (M1, 2), 160 (40),
144 (48), 91 (100); HRMS Calcd for C13H16O3 m/z
234.1256, found: 234.1239.
NMR (CDCl3) d 1.75±1.89 (m, 2H), 2.21 (s, 3H, CH3), 2.37
(qd, Jˆ7.1, 1.4 Hz, 2H), 3.49 (t, Jˆ6.2 Hz, 2H), 4.49 (s,
2H), 6.06 (dt, Jˆ16.0, 1.5 Hz, 1H), 6.81 (dt, Jˆ16.0,
6.8 Hz, 1H), 7.26±7.35 (m, 5H, aromatic-H); 13C NMR
(CDCl3) d 26.75, 28.15, 29.16, 69.15, 72.88, 127.54,
128.30, 131.41, 138.26, 147.68, 198.51 (CvO); MS (m/z):
218 (M1, 1), 200 (1), 175 (6), 160 (15), 142 (10), 127 (10),
105 (12), 91 (100), 84 (30), 69 (0); HRMS Calcd for
C14H18O2 m/z 218.1307, found: 218.1336.
4-Trityloxy-2(E)-butenoic acid methyl ester (5ja-E).
Colorless oil; H NMR (CDCl3) d 3.77 (s, 3H, OCH3),
1
3.80 (dd, Jˆ3.8, 2.1 Hz, 2H), 6.37 (dt, Jˆ15.6, 2.1 Hz,
1H, CvCH±CO), 6.97 (dt, Jˆ15.6, 3.8 Hz, 1H,
CHvCH±CO), 6.90±7.50 (m, 15H, aromatic-H); 13C
NMR (CDCl3) d 51.58, 63.06, 87.08 (±CPh3), 119.95,
126.95, 127.21, 127.95, 128.51, 128.71, 128.83, 143.68,
145.16, 167.04 (CvO); IR (CH2Cl2): 3178, 3055, 1706
(CvO), 1465, 1282, 1161, 1079, 927 cm21; MS (m/z)
(27 eV): 359 (M111, 4), 281 (18), 144 (50), 243 (100),
165 (26), 105 (78), 99 (23); HRMS Calcd for C24H22O3
m/z 359.1647, found: 359.1622.
5-Trityloxy-3(E)-penten-2-one (5jc-E). Viscous pale
yellow oil; H NMR (CDCl3) d 2.25 (s, 3H, CH3), 3.84
1
(dd, Jˆ3.6, 1.8 Hz, 2H), 6.51 (dt, Jˆ16.1, 1.8 Hz, 1H),
6.74 (dt, Jˆ16.1, 3.1 Hz, 1H), 7.18±7.48 (m, 15H,
aromatic-H); 13C NMR (CDCl3) d 27.07, 63.09, 87.11,
127.19, 127.93, 128.46, 129.48, 143.60, 143.78, 198.41
(CvO); IR (CH2Cl2): 3027, 1680, 1650, 1630, 1481,
1436, 1355, 1251, 1210, 1150, 1065, 1018, 967 cm21; MS
(m/z): 342 (M1, 1), 324 (10), 265 (18), 243 (100), 228 (10),
183 (12), 165 (66), 160 (17), 149 (8), 105 (76), 91 (8), 83
(30), 77 (13); HRMS Calcd for C24H22O2 m/z 342.1620,
found: 342.1600.
4-Trityloxy-2(Z)-butenoic acid methyl ester (5ja-Z).
Colorless oil; H NMR (CDCl3) d 3.60 (s, 3H, OCH3),
1
4.33 (dd, Jˆ4.7, 2.5 Hz, 2H), 5.70 (dt, Jˆ11.7, 2.5 Hz,
1H, CvCH±CO), 6.47 (dt, Jˆ11.7, 4.7 Hz, 1H,
CHvCH±CO), 7.20±7.51 (m, 15H, aromatic-H); 13C
NMR (CDCl3) d 51.12, 63.03, 87.03, 118.14, 127.04,
127.84, 128.09, 128.67, 143.90, 149.06, 166.27 (CvO);
IR (CH2Cl2): 3054, 1706 (CvO), 1587, 1466, 1284, 1161,
1079, 927 cm21; MS (m/z) (70 eV): 358 (M1, 1), 259
(M12CH2CHvCHCO2Me, 6) 243 (10), 228 (3), 165 (6),
105 (8), 78 (100); HRMS Calcd for C24H22O3 m/z 358.1569,
found: 358.1558.
General procedure for the ozonolysis of 1,1-disubsti-
tuted alkenes
In a 25 mL of two-neck ¯ask, equipped with a magnetic
stirrer, a drying tube and a gas dispersing tube (with porous
fritted tip), were placed 15 mL of pentane and benzyl
methallyl ether (8) (306 mg, 1.9 mmol). A stream of
ozone was bubbled through the solution at 2788C. Ozone
treatment was terminated when the mixtures assumed a blue
color. A stream of nitrogen removed excess ozone. The
mixtures were then allowed to warm up to room tempera-
ture. It was concentrated and chromatographed on a silica
gel column by elution with EtOAc/hexane (1/20) to give
ozonide 9 (250 mg, 63% yield) as a colorless oil.
5-Benzyloxy-3(E)-penten-2-one (5gc-E). Colorless oil; 1H
NMR (CDCl3) d 2.27 (s, 3H, CH3), 4.21 (dd, Jˆ4.4, 2.0 Hz,
2H), 4.58 (s, 2H), 6.36 (dt, Jˆ16.1, 1.9 Hz, 1H), 6.81 (dt,
Jˆ16.1, 4.4 Hz, 1H), 7.27±7.38 (m, 5H, aromatic-H); 13C
NMR (CDCl3) d 27.16, 68.71, 72.84, 127.60, 127.79,
128.41, 130.25, 137.53, 142.91, 198.04 (CvO); IR
(CH2Cl2): 3031, 1675 (CvO), 1632, 1436, 1359, 1261,
1120, 1021, 975 cm21; MS (m/z): 189 (M121, 20), 161
(50), 149 (82), 119 (40), 111 (42), 97 (58), 85 (73), 71
(100); HRMS Calcd for C12H13O2 m/z 189.0916, found:
189.0935.
3-Benzyloxymethyl-3-methyl-1,2,4-trioxolane (9). Color-
less oil; H NMR (CDCl3) d 1.54 (s, 3H, CH3), 3.44 (d,
1
Jˆ10.8 Hz, 1H), 3.54 (t, Jˆ10.8 Hz, 1H), 4.57 (d,
Jˆ12.0 Hz, 1H), 4.64 (d, Jˆ12.0 Hz, 1H), 5.03 (s, 1H),
5.18 (s, 1H), 7.28±7.36 (m, 5H, aromatic-H); 13C NMR
(CDCl3) d 19.05, 71.65, 73.51, 93.95, 108.21, 127.62,
127.92, 128.37, 137.80; IR (CH2Cl2): 3032, 1449, 1367,
1231, 1107, 1059, 1009, 945 cm21; MS (m/z): 210 (M1,
1), 120 (20), 107 (5), 91 (100), 65 (6), 43 (10); HRMS
Calcd for C11H14O4 m/z 210.0892, found: 210.0890.
1
5-Benzyloxy-3(Z)-penten-2-one (5gc-Z). Colorless oil; H
NMR (CDCl3) d 2.22 (s, 3H, CH3), 4.54 (s, 2H), 4.59 (dd,
Jˆ4.2, 2.0 Hz, 2H), 6.22±6.35 (m, 2H), 7.26±7.36 (m, 5H,
aromatic-H); 13C NMR (CDCl3) d 31.05, 69.47, 72.92,
125.95, 127.79, 127.93, 128.44, 147.03, 194.11 (CvO);
IR (CH2Cl2): 2933, 1725 (CvO), 1684, 1612, 1544, 1490,
1394, 1252, 1184, 1100, 1021 cm21; MS (m/z): 190 (M1, 2),
146 (10), 131 (12), 99 (21), 91 (100), 84 (51), 77 (52), 69
(18), 43 (21); HRMS Calcd for C12H14O2 m/z 190.0994,
found: 190.0990.
Reaction of 1,1-disubstituted ozonide with stable phos-
phonium ylide
1
6-Benzyloxy-3(E)-hexen-2-one (5hc-E). Colorless oil; H
NMR (CDCl3) d 2.21 (s, 3H, CH3), 2.50 (qd, Jˆ6.7, 1.5 Hz,
2H), 3.57 (t, Jˆ6.4 Hz, 2H), 4.49 (s, 2H), 6.10 (dt, Jˆ16.0,
1.5 Hz, 1H), 6.80 (dt, Jˆ16.0, 6.8 Hz, 1H), 7.24±7.35 (m,
5H, aromatic-H); 13C NMR (CDCl3) d 26.49, 32.56, 67.93,
72.70, 127.39, 128.13, 132.35, 137.79, 144.60, 198.15
(CvO); MS (m/z): 204 (M1, 1), 189 (1), 174 (2), 160 (1),
146 (1), 131 (2), 117 (1), 107 (1), 98 (35), 91 (100), 83 (9),
77 (2), 65 (8); HRMS Calcd for C13H16O2 m/z 204.1151,
found: 204.1098.
To a solution of ozonide 9 (250 mg, 1.19 mmol) in 15 mL of
CH2Cl2 was added Ph3PvCHCO2Me (4a) (401.2 mg,
1.2 mmol) at 08C and the reaction was warmed slowly to
ambient temperature. After 12 h, the reaction mixture was
concentrated and chromatographed on a silica gel column.
3-Benzyloxypropanone (10) (172 mg, 88% yield), benzyl-
oxymethyl acetate (11) (17.1 mg, 8% yield) and the phos-
phonium salt (380 mg) were isolated. This phosphonium
salt was treated with 1N NaOH and then extracted with

Y.-S. Hon et al. / Tetrahedron 56 (2000) 9269±9279
9279
3. (a) Sousa, J. A.; Bluhm, A. L. J. Org. Chem. 1960, 25, 108.
(b) Greenwood, F. L. J. Org. Chem. 1955, 20, 803. (c) Story, P. R.;
Bishop, C. E.; Burgess, J. R.; Murray, R. W.; Youssefyeh, R. D.
J. Am. Chem. Soc. 1968, 90, 1907. (d) Bishop, C. E.; Story, P. R.
J. Am. Chem. Soc. 1968, 90, 1905.
benzene to give the phosphonium ylide 4a (329 mg,
0.98 mmol).
3-Benzyloxypropanone (10). Colorless oil; 1H NMR
(CDCl3) d 2.16 (s, 3H, CH3), 4.59 (s, 2H, PhCH2), 4.87
(s, 2H, COCH2), 7.26±7.39 (m, 2H, aromatic-H); IR
(CH2Cl2): 3032, 1726 (CvO), 1417, 1353, 1211, 1115,
1026, 976 cm21; MS (m/z): 164 (M1, 2), 107 (50), 91
(100), 77 (8), 65 (15), 43 (40); HRMS Calcd for C10H12O2
m/z 164.0837, found: 164.0830.
4. (a) Hon, Y. S.; Lu, L.; Li, S. Y. J. Chem. Soc., Chem. Commun.
1990, 1627. (b) Hon, Y. S.; Chang, R. C.; Chu, K. P.; Lin, S. W.
Youji Huaxue 1993, 13, 285. (c) Hon, Y. S.; Chu, K. P.; Hong, P. C.;
Lu, L. Synth. Commun. 1992, 22, 429.
5. Sakurai, H.; Hosomi, A.; Hayashi, J. Org. Synth. 1990, 7, 443.
6. (a) Hon, Y. S.; Lu, L.; Chang, R. C.; Chu, K. P. Heterocycles
1991, 32, 437. (b) Hon, Y. S.; Yan, J. L. Tetrahedron Lett. 1993,
34, 6591. (c) Hon, Y. S.; Yan, J. L. Tetrahedron Lett. 1994, 35,
1743. (d) Hon, Y. S.; Chang, F. J.; Lu, L. J. Chem. Soc., Chem.
Commun. 1994, 2041. (e) Hon, Y. S.; Yan, J. L. Tetrahedron 1997,
53, 5217. (f) Hon, Y. S.; Yan, J. L. Tetrahedron 1998, 54, 8525.
(g) Hon, Y. S.; Chang, F. J.; Lu, L.; Lin, W. C. Tetrahedron 1998,
54, 5233.
Benzyloxymethyl acetate (11). Colorless oil; 1H NMR
(CDCl3) d 2.07 (s, 3H, CH3), 4.69 (s, 2H, PhCH2), 5.34
(s, 2H, OCH2O), 7.31±7.36 (m, 5H, aromatic-H); IR
(CH2Cl2): 3032, 1736 (CvO), 1451, 1363, 1227, 1162,
1116, 1010, 945 cm21; MS (m/z): 180 (M1, 2), 120 (58),
119 (27), 91 (100), 77 (8), 65 (10), 43 (31); HRMS Calcd for
C10H12O3 m/z 180.0786, found: 180.0781.
7. Davis, F. A.; Chen, B. C. J. Org. Chem. 1990, 55, 360.
8. Hon, Y. S.; Lu, L.; Chu, K. P. Synth. Commun. 1991, 21, 1981.
9. Maryanoff, B. E.; Beitz, A. B. Chem. Rev. 1989, 89, 863.
10. (a) Hon, Y. S.; Lin, S. W.; Chen, Y. J. Synth. Commun. 1993,
24, 1543. (b) Hon, Y. S.; Lu, L. Tetrahedron Lett. 1993, 34, 5309.
(c) Hon, Y. S.; Lin, S. W.; Lu, L.; Chen, Y. J. Tetrahedron 1995,
51, 5019.
Acknowledgements
We are grateful to the National Science Council, Academic
Sinica and National Chung Cheng University, Republic of
China for the ®nancial support.
11. Ruchardt, C.; Eichler, S.; Panse, P. Angew. Chem. 1963, 2,
619.
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