Dimethyldioxirane oxidation of (E,E)-cinnamylideneacetophenones

Article abstract of DOI:10.1002/1099-0690(200109)2001:17<3213::AID-EJOC3213>3.0.CO;2-K

The (E,E)-cinnamylideneacetophenones 1a-f were oxidised by isolated dimethyldioxirane (DMD, as acetone solution) at room temperature, giving diastereomeric mixtures of the α,β:γ,δ-diepoxides 3a-f when an excess of oxidant was used. α,β-Monoepoxides, found as minor components of the reaction, could be detected in only two cases (2c,d) when one equivalent of DMD was used. Dimethyldioxirane oxidation of (E,E)-2′-hydroxycinnamylideneacetophenones (4a-d) led to the formation of diastereomeric mixtures of the α,β:γ,δ-diepoxides 6a-d as well as to the γ,δ-monoepoxides 5a-d as minor products. The diepoxides 6a-d were transformed into the isolable coumaranone derivatives 7a-d during their chromatographic purification. All the compounds described have been fully characterised by NMR spectroscopy.

Full text of DOI:10.1002/1099-0690(200109)2001:17<3213::AID-EJOC3213>3.0.CO;2-K

SHORT COMMUNICATION
Dimethyldioxirane Oxidation of (E,E)-Cinnamylideneacetophenones
[a]
[b]
[b]
[a]
´
´
´
Albert Levai,* Artur M. S. Silva, Jose A. S. Cavaleiro, Tamas Patonay, and
Vera L. M. Silva[b]
Keywords: Enones / Epoxidation / Ketones / NMR spectroscopy
The (E,E)-cinnamylideneacetophenones 1a−f were oxidised
of (E,E)-2Ј-hydroxycinnamylideneacetophenones (4a−d) led
by isolated dimethyldioxirane (DMD, as acetone solution) at to the formation of diastereomeric mixtures of the α,β:γ,δ-di-
room temperature, giving diastereomeric mixtures of the
α,β:γ,δ-diepoxides 3a−f when an excess of oxidant was used.
epoxides 6a−d as well as to the γ,δ-monoepoxides 5a−d as
minor products. The diepoxides 6a−d were transformed into
α,β-Monoepoxides, found as minor components of the reac- the isolable coumaranone derivatives 7a−d during their chro-
tion, could be detected in only two cases (2c,d) when one
matographic purification. All the compounds described have
equivalent of DMD was used. Dimethyldioxirane oxidation been fully characterised by NMR spectroscopy.
Introduction
mones by the oxidative transformation of 2Ј-hydroxycinna-
mylideneacetophenones with thallium(III) trinitrate.[6] Al-
though various oxidative transformations of these unsatur-
ated ketones have already been performed, to the best of
our knowledge their epoxidation has not yet been published
in the literature.
(E,E)-Cinnamylideneacetophenones are well-known un-
saturated ketones. The first synthesis of their parent com-
pound 1,5-diphenylpenta-2,4-dien-1-one (1a) was reported
as early as 1895.[1] Since then the synthesis and chemical
transformations of a wide variety of substituted derivatives
have been described in the literature. However, their epoxid-
ation has hitherto received less attention. The α,β-mono-
epoxide of 1,5-diphenylpenta-2,4-dien-1-one was first pre-
pared by Weitz and Scheffer in l921.[2] An asymmetric syn-
thesis of the α,β-monoepoxides of (E,E)-cinnamylideneace-
tophenones and related unsaturated ketones was performed
All these facts prompted us to investigate the epoxidation
of (E,E)-cinnamylideneacetophenones as well as their 2Ј-
hydroxy derivatives. On the basis of its successful utilisation
for the epoxidation of a wide variety of unsaturated com-
pounds, dimethyldioxirane appeared to be a convenient re-
agent for this purpose. This highly effective oxidant was ad-
vantageously used even in the case of electron-deficient ol-
efins, such as chalcones and related α,β-unsaturated ke-
tones,[7] or for the stereoselective epoxidation of exocyclic
α,β-enones.[8] Since the dimethyldioxirane acts under
strictly neutral conditions, it proved to be the best reagent
for the epoxidation of 2Ј-hydroxychalcones[9] because these
epoxides are extremely unstable under both acidic and basic
conditions. As a result, the preparation of such epoxides
was impossible with any other oxidant. Dimethyldioxirane
and methyl(trifluoromethyl)dioxirane have been used suc-
cessfully for the regioselective epoxidation of dienes and tri-
enes as well.[10] Herein we report the dimethyldioxirane ox-
idation of (E,E)-cinnamylideneacetophenones and their 2Ј-
hydroxy derivatives.
by Julia’s enantioselective epoxidation.[3] However, these ex-
´
periments can only be considered as sporadic attempts to
study the epoxidation of such unsaturated ketones.
2Ј-Hydroxycinnamylideneacetophenones [5-aryl-1-(2-hy-
droxyphenyl)penta-2,4-dien-1-ones] are important interme-
diates in the synthesis of biologically active compounds,
and some of their oxidative transformations have already
been investigated in detail. Probably the first example for
the oxidative conversion of 2Ј-hydroxycinnamylideneaceto-
phenones into 2-styrylchromones and 3-hydroxy-2-styryl-
chromones by treatment with selenium dioxide and alkaline
hydrogen peroxide, respectively, was reported by Marini-
Bettolo.[4] Recently, we have studied the oxidative cyclis-
ation of 2Ј-hydroxycinnamylideneacetophenones with di-
methyl sulfoxide in the presence of a catalytic amount of
iodine, and new procedures have been developed for the
synthesis of 2-styrylchromone derivatives.[5] We have also
developed a new method for the synthesis of 3-styrylchro-
Results and Discussion
Epoxidation Experiments
Since the cinnamylideneacetophenones have two double
bonds to be epoxidised, one of our aims was to investigate
the regioselectivity of their epoxidation with dimethyldioxi-
rane. For this purpose, compounds 1aϪf were allowed to
react with one equivalent of isolated dimethyldioxirane in
acetone (0.05Ϫ0.10 ) at room temperature; a multicom-
ponent crude reaction product was obtained in each case.
[a]
Department of Organic Chemistry, University of Debrecen
4010 Debrecen, Hungary
Fax: (internat.) ϩ36-52/453-836
E-mail: alevai@tigris.klte.hu
Department of Chemistry, University of Aveiro
3810-193 Aveiro, Portugal
Fax: (internat.) ϩ351-234/370-084
E-mail: arturs@dq.ua.pt
[b]
Eur. J. Org. Chem. 2001, 3213Ϫ3219
WILEY-VCH Verlag GmbH, 69451 Weinheim, 2001
1434Ϫ193X/01/0917Ϫ3213 $ 17.50ϩ.50/0
3213

´
A. Levai, A. M. S. Silva, J. A. S. Caveleiro, T. Patonay, V. L. M. Silva
SHORT COMMUNICATION
In these mixtures a substantial amount of starting material,
α,β:γ,δ-diepoxides and several minor components were de-
tected by thin-layer chromatography. The starting materials
1aϪf and the α,β:γ,δ-diepoxides 3aϪf were separated from
the mixtures by preparative thin-layer chromatography. The
α,β-monoepoxide could be observed and characterised by
NMR spectroscopy of these mixtures in only two cases
(2c,d, Scheme 1). However, the isolation of these α,β-mono-
epoxides was not possible in any case, even after a careful
chromatographic analysis.
Table 1. Diastereomeric mixtures of α,β,γ,δ-Diepoxides 3aϪd
Compound
(yellow oil)
Molecular
formula
Yield
(%)
Component (%)
Major
Minor
3a
3b
3c
3d
3e
3f
C17H14O3
C18H16O3
C18H16O4
C17H13FO3
C17H13ClO3
C17H13BrO3
60
62
55
60
63
59
65
64
65
67
68
68
35
36
35
33
32
32
case. An NMR analysis of these reaction mixtures allowed
the characterisation of the γ,δ-monoepoxides 5aϪd and the
diastereomeric mixtures of α,β:γ,δ-diepoxides 6aϪd. How-
ever, a preparative silica gel thin-layer chromatographic
analysis of these mixtures led to the isolation of the γ,δ-
monoepoxides 5aϪd and the new compounds 7aϪd; the
α,β:γ,δ-diepoxides 6aϪd were not detected (Scheme 2). The
coumaranone derivatives 7aϪd were obtained by cyclisation
of the α,β:γ,δ-diepoxides 6aϪd on silica gel, probably due
to the acidic character of the silica gel. This behaviour is in
accordance with our previous observations on the epoxida-
tions of 2Ј-hydroxyacrylophenone and 1-(2-hydroxyphenyl)-
2-alken-1-ones, where the labile epoxides cyclised spontan-
eously giving the analogous 2-(α-hydroxyalkyl)-3-coumar-
anones.[9] The coumaranone derivatives 7aϪd were also ob-
tained as diastereomeric mixtures (Scheme 2).
Scheme 1
The α,β-double bond was epoxidised regioselectively by
other oxidising agents (vide supra)[2,3] which means that it
is more reactive towards a nucleophilic oxidant than the
γ,δ-bond. However, this regioselectivity seems to be much
less pronounced in the case of an electrophilic oxidant like
dimethyldioxirane. For this reason, the α,β:γ,δ-diepoxide is
the major oxidised product even when using only one
equivalent of dimethyldioxirane; the appropriate α,β-mono-
epoxide is only a minor component in the reaction mixture
and could not be isolated in every case. The α,β-monoepox-
ides 2c,d were characterised by H and 13C NMR spectro-
1
scopy.
The complete conversion of the (E,E)-cinnamylideneace-
tophenones 1aϪf required four equivalents of dimethyldi-
oxirane to afford the α,β:γ,δ-diepoxides 3aϪf (Scheme 1
and Table 1). No minor component could be isolated after
column chromatography, and compounds 3aϪf were the
only isolable products. On this basis it appears that there is
a minimum regioselectivity between the two double bonds
Scheme 2
Contrary to compounds 1aϪf, the dimethyldioxirane ox-
towards this electrophilic oxidant. 1H and 13C NMR meas- idation of the (E,E)-2Ј-hydroxycinnamylideneaceto-
urements (vide infra) revealed that approximately 2:1 mix- phenones 4aϪd led to the isolation of the γ,δ-monoepox-
tures of diastereomeric α,β:γ,δ-diepoxides were formed in ides 5aϪd (Scheme 2) by preparative thin-layer chromato-
all cases. Separation of the two diastereomeric α,β:γ,δ-diep- graphy. The formation of such monoepoxides might be en-
oxides was not possible.
visaged in two ways: i) the formation of coumaranone-type
Epoxidation of the (E,E)-2Ј-hydroxycinnamylideneaceto- compounds by the attack of the 2-hydroxy group at the β-
phenones 4aϪd by dimethyldioxirane seemed to be an espe- carbon, leaving only the γ,δ-double bond available for epox-
cially interesting challenge since this oxidant has been idation, or ii) the intramolecular hydrogen bond between
shown to be the reagent of choice for an effective prepara- the 2Ј-hydroxy and the carbonyl groups may enhance the
tion of the epoxides of 2Ј-hydroxychalcones.[9] For this reactivity of the γ,δ-double bond towards the dimethyldi-
reason, compounds 4aϪd were allowed to react with 3Ϫ5 oxirane. The first hypothesis was ruled out since we fol-
equivalents of dimethyldioxirane, at ambient temperature, lowed the epoxidation reaction of 4a by NMR spectroscopy
for 72Ϫ120 h, to give a complete conversion of the starting and no coumaranone was observed: only the γ,δ-mono-
2Ј-hydroxycinnamylideneacetophenones (Scheme 2). As a epoxide 5a and the α,β:γ,δ-diepoxide 6a were formed; no
result, a multicomponent mixture was obtained in each α,β-monoepoxide could be observed. The epoxidation of 2Ј-
3214
Eur. J. Org. Chem. 2001, 3213Ϫ3219

Dimethyldioxirane Oxidation of (E,E)-Cinnamylideneacetophenones
SHORT COMMUNICATION
acetoxycinnamylideneacetophenone lead to the formation NMR spectra of the reaction mixtures suggest the forma-
of the corresponding α,β:γ,δ-diepoxide and to the α,β-mono- tion of a diastereomeric mixture of the α,β:γ,δ-diepoxides
epoxide as minor product, as in the case of compounds 6aϪd of the 2Ј-hydroxycinnamylideneacetophenones 4aϪd.
1aϪf without the 2Ј-hydroxy group, thus confirming that The COSY spectra of these mixtures revealed the presence
the intramolecular hydrogen bond mentioned previously of two spin systems (δ ϭ 4.29Ϫ4.40, 3.39Ϫ3.43, 3.19Ϫ3.21,
enhances the reactivity of the γ,δ-double bond towards the 3.91Ϫ3.94 and δ ϭ 4.31Ϫ4.42, 3.49Ϫ3.53, 3.28Ϫ3.31,
dimethyldioxirane.
3.94Ϫ3.98), which were assigned to the resonances of H-α/
H-β and H-γ/H-δ of the two diastereomers of the diepox-
ides 6aϪd, respectively. The assignment of H-α and H-δ
NMR Spectroscopy
1
The aliphatic region of the H NMR spectra of the isol- was confirmed by the connectivities found in the HMBC
ated compounds 3aϪf presents two groups of four signals spectra of these mixtures (Figure 1), the former with the
(δ ϭ 4.27Ϫ4.33, 3.30Ϫ3.35, 3.15Ϫ3.18, 3.87Ϫ3.92 and δ ϭ carbonyl carbon (CϭO) and the latter with the C-1 and C-
4.29Ϫ4.33, 3.38Ϫ3.46, 3.23Ϫ3.28, 3.89Ϫ3.95), which were 2,6 carbon atoms. Other important connectivities found in
assigned to two spin systems by the analysis of their COSY these HMBC spectra are those of the hydroxylic proton (2Ј-
spectra. These signals were attributed to the resonances of OH) with C-1Ј, C-2Ј and C-3Ј, and also those of H-6Ј with
H-α, H-β, H-γ and H-δ of a diastereomeric mixture of the C-2Ј, C-4Ј and CϭO, which allowed the assignment of these
α,β:γ,δ-diepoxides 3aϪf, in a ratio of approximately 2:1. carbon resonances and support the structure of the diaster-
The carbon resonances of C-α, C-β, C-γ and C-δ of these eomers of the α,β:γ,δ-diepoxides 6aϪd. The assignments of
diastereomers 3aϪf were assigned based on the correlations the majority of the protonated carbon resonances of these
found in their HSQC (δ
ϭ 54.2Ϫ54.7, 57.2Ϫ57.7, two diastereomeric diepoxides 6aϪd were made by the ana-
59.3Ϫ59.7, 56.7Ϫ57.6 and δ ϭ 53.7Ϫ54.2, 56.2Ϫ56.4, lysis of the HSQC spectra of the referred reaction mixtures.
58.5Ϫ58.8, 55.8Ϫ56.3, respectively). The assignments of H-
α (δ ϭ 4.27Ϫ4.33 and 4.29Ϫ4.33) were confirmed by the
connectivities found in the HMBC spectra with the car-
bonyl carbon resonances (δ ϭ 191.2Ϫ192.9), whereas those
of H-δ (δ ϭ 3.87Ϫ3.92 and 3.89Ϫ3.95) show connectivities
with the carbon resonances of C-1 (δ ϭ 135.3Ϫ135.7) and
C-2,6 (δ ϭ 125.4Ϫ125.7). The analysis of the NOESY spec-
tra of 3aϪf did not allow us to determine the stereochem-
istry of these diastereomers.
1
In the H NMR spectra of the mixtures obtained in the
reactions of 1c,d with one equivalent of dimethyldioxirane
it was possible to identify the proton resonances of the dia-
stereomeric mixtures of diepoxides 3c,d and also four other
Figure 1. Main connectivities found in the HMBC spectra of com-
pounds 5aϪd, 6aϪd and 7aϪd
resonances at
δ ϭ 4.26Ϫ4.27, 3.73Ϫ3.74, 6.03 and
6.88Ϫ6.90 could be observed. In the HSQC spectra of such
mixtures, these resonances correlate with the carbon signals
at
δ
ϭ
59.0Ϫ59.3, 59.6Ϫ59.8, 124.2Ϫ124.4 and
136.2Ϫ136.7, respectively, and their COSY spectra revealed
By careful thin-layer chromatographic analysis of the re-
that they belong to only one spin system. These results sug- action mixtures of the 2Ј-hydroxycinnamylideneaceto-
gest the presence of monoepoxides of compounds 1c,d. The phenones 4aϪd with dimethyldioxirane two sets of com-
unequivocal assignment of the structures of these mono- pounds were isolated, one being the monoepoxides 5aϪd
epoxides 2c,d was based on the connectivities found in the and the other being compounds 7aϪd (Scheme 2); the
HMBC spectra of these reaction mixtures. The proton res- α,β:γ,δ-diepoxides 6aϪd were not detected.
onances at δ ϭ 3.73Ϫ3.74 and 6.03 correlate with those
The main characteristics of the 1H NMR spectra of com-
of CϭO (δ ϭ 191.4Ϫ191.8) and C-1 (δ ϭ 135.7Ϫ135.8), pounds 5aϪd were the proton resonances at δ ϭ 7.32Ϫ7.40,
respectively, and were assigned to H-β and H-γ, respect- 7.06Ϫ7.13, 3.62Ϫ3.65, 3.90Ϫ3.91 and 12.29Ϫ12.62, the lat-
ively, thus confirming the presence of the α,β-monoepox- ter being assigned to the 2Ј-OH proton. These data and the
ides 2c,d (Scheme 1).
corresponding carbon resonances (δ ϭ 124.1Ϫ125.3,
1
The H NMR spectra of the mixtures obtained from the 144.2Ϫ147.7, 60.9Ϫ61.1 and 61.8Ϫ62.0), assigned with the
reaction of the 2Ј-hydroxycinnamylideneacetophenones aid of the HSQC spectra, suggest the presence of a mono-
4aϪd with an excess (3Ϫ5 equivalents) of dimethyldioxirane epoxide in each case. However, the correlations observed in
show three hydroxylic proton resonances at
δ
ϭ
the HMBC spectra of 5aϪd (Figure 1) between the proton
11.52Ϫ11.80, 11.55Ϫ11.85 and 12.29Ϫ12.62. The latter was resonances at δ ϭ 7.32Ϫ7.40 and 7.06Ϫ7.13 and those of
assigned to the 2Ј-OH of the monoepoxides 5aϪd, as was the carbonyl carbons, allowed us to assign these proton res-
proved (vide infra) after their isolation by thin-layer chro- onances to H-α and H-β, respectively, and to unequivocally
matography. The presence of the other two hydroxylic res- prove the structure of the γ,δ-monoepoxides 5aϪd
1
onances and the analysis of the aliphatic region of the H (Scheme 2). Other important correlations observed in the
Eur. J. Org. Chem. 2001, 3213Ϫ3219
3215

´
A. Levai, A. M. S. Silva, J. A. S. Caveleiro, T. Patonay, V. L. M. Silva
SHORT COMMUNICATION
hydrochloric acid. The precipitate was filtered off, washed with
HMBC spectra of 5aϪd are those of H-δ (δ ϭ 3.90Ϫ3.91)
with C-1 and C-2,6 and also those of the hydroxylic proton
with C-1Ј, C-2Ј and C-3Ј, which supports the structure of
the γ,δ-monoepoxides 5aϪd.
water and recrystallised from methanol to obtain 6.4 g of 4b (80%)
1
as yellow crystals, m.p. 138Ϫ139 °C. H NMR: δ ϭ 2.36 (s, 3 H,
CH3), 6.73 (br. d, J ϭ 8.1 Hz, 1 H, H-5Ј), 6.82 (br. s, 1 H, H-3Ј),
6.98Ϫ7.12 (m, 2 H, H-γ,δ), 7.19 (d, J ϭ 14.7 Hz, 1 H, H-α),
7.31Ϫ7.41 (m, 3 H, H-3,4,5), 7.51 (d, J ϭ 6.7 Hz, 1 H, H-2,6),
7.64Ϫ7.73 (m, 1 H, H-β), 7.72 (d, J ϭ 8.1 Hz, 1 H, H-6Ј), 12.98 (s,
1 H, 2Ј-OH). Ϫ 13C NMR: δ ϭ 22.0 (CH3), 117.8 (C-1Ј), 118.6 (C-
3Ј), 120.1 (C-α), 126.7 (C-γ), 127.4 (C-2,6), 128.9 (C-3,5), 129.38
and 129.41 (C-4 and C-6Ј), 136.0 (C-1), 142.6 (C-δ), 145.0 (C-β),
The analysis of the aliphatic region of the 1H NMR spec-
tra of compounds 7aϪd with the aid of the COSY spectra
allowed the assignment of four signals of two spin systems
(δ ϭ 4.73Ϫ4.79, 4.39Ϫ4.45, 3.36Ϫ3.38, 3.99Ϫ4.08 and δ ϭ
4.76Ϫ4.82, 4.39Ϫ4.45, 3.24Ϫ3.25, 3.96Ϫ4.10). These pro-
ton resonances correlate in the HSQC spectra with those 148.0 (C-4Ј), 163.7 (C-2Ј), 193.1 (CϭO). Ϫ C18H16O2 (264.3):
calcd. C 81.79, H 6.10; found C 81.72, H 6.12.
of the carbons at δ ϭ 84.4Ϫ85.5, 69.5Ϫ69.6, 61.3Ϫ61.5,
56.0Ϫ56.4 and δ ϭ 84.4Ϫ85.6, 69.8Ϫ69.9, 60.0Ϫ60.4,
55.4Ϫ55.8, respectively. All these data suggest that the
α,β:γ,δ-diepoxides 6aϪd were transformed into new com-
pounds during the thin-layer chromatographic purification.
These new compounds retain one oxirane ring while the
other epoxide has reacted with the 2Ј-hydroxy group. The
connectivities found in the HMBC spectra of 7aϪd between
the protons of each methynic group (H-2, δ ϭ 4.73Ϫ4.79
and 4.76Ϫ4.82) with the carbonyl groups (C-3), with the
strongly deshielded quaternary carbon (C-8), with the car-
bon of the epoxide ring (C-2Ј) and with another methynic
carbon (C-1Ј) led us to suppose the formation of a coumar-
anone-type structure by oxirane ring opening at the α-posi-
tion (7aϪd, Scheme 2). Other important connectivities are
those of H-4 with C-3, C-6 and C-8 and also of H-3Ј with
C-1ЈЈ and C-2ЈЈ,6ЈЈ (Figure 1), which allowed us to assign
these carbon resonances and support the structures shown
for compounds 7aϪd.
(E,E)-5Ј-Fluoro-2Ј-hydroxycinnamylideneacetophenone (4c): Ac-
cording to the procedure described for 4b, 5Ј-fluoro-2Ј-hydroxyace-
tophenone (4.6 g, 30 mmol) afforded 4c (6.1 g, 76%) as yellow crys-
tals, m.p. 159Ϫ160 °C. 1H NMR: δ ϭ 6.98 (dd, JH-F ϭ 4.6 and JH-
ϭ 8.8 Hz, 1 H, H-3Ј), 7.04Ϫ7.13 (m, 2 H, H-γ,δ), 7.10 (d, J ϭ
H
14.9 Hz, 1 H, H-α), 7.23 (dt, JH-F ϭ 8.8 and JH-H ϭ 2.9 and 8.8 Hz,
1 H, H-4Ј), 7.33Ϫ7.42 (m, 3 H, H-3,4,5), 7.51 (dd, JH-F ϭ 8.8 and
JH-H ϭ 2.9 Hz, 1 H, H-6Ј), 7.52Ϫ7.54 (m, 2 H, H-2,6), 7.74 (ddd,
J ϭ 1.5, 8.0 and 14.9 Hz, 1 H, H-β), 12.64 (s, 1 H, 2Ј-OH). Ϫ 13C
NMR: δ ϭ 114.4 (d, JC-F ϭ 23.3 Hz, C-3Ј), 119.4 (d, JC-F ϭ 6.0 Hz,
C-1Ј), 119.7 (d, JC-F ϭ 7.2 Hz, C-3Ј), 122.8 (C-α), 123.7 (d, JC-F ϭ
23.5 Hz, C-4Ј), 126.4 (C-γ), 127.5 (C-2,6), 128.9 (C-3,5), 129.7 (C-
4), 135.7 (C-1), 143.6 (C-δ), 146.3 (C-β), 154.8 (d, JC-F ϭ 238.2 Hz,
C-5Ј), 159.6 (C-2Ј), 192.7 (d, JC-F ϭ 2.5 Hz, CϭO). Ϫ C17H13FO2
(268.3): calcd. C 76.11, H 4.88; found C 76.07, H 4.85.
General Procedure for the Preparation of the α,β:γ,δ-Diepoxides
3aϪf of the (E,E)-Cinnamylideneacetophenones 1aϪf: The required
amount of isolated dimethyldioxirane in acetone (0.05Ϫ0.10 ) was
added to a solution of the appropriate (E,E)-cinnamylideneaceto-
phenone (1aϪf; 1.17Ϫ1.57 g, 5.0 mmol) in anhydrous dichlorome-
thane (20 mL) at room temperature. The mixture was left to stand
at room temperature and another equivalent of dimethyldioxirane
was added every day until the complete consumption of the starting
material 1aϪf. A complete conversion of the starting materials into
the appropriate α,β:γ,δ-diepoxides was achieved by using four
equivalents of dimethyldioxirane in 96 h. The solvent was then
evaporated under reduced pressure (ca. 20 Torr) and the residue
was purified by column chromatography [hexane/acetone (7:3 v/v)
as eluent] to yield the diepoxides 3aϪf (Scheme 1 and Table 1).
Experimental Section
General Remarks: Melting points (uncorrected): Reichert Thermo-
var apparatus fitted with a microscope. Ϫ FT NMR: Bruker DRX
300 spectrometer (300.13 and 75.47 MHz, for 1H and 13C, respect-
ively); CDCl3 as solvent, TMS as internal reference, chemical shifts
1
(δ) in ppm, coupling constants (J) in Hertz (Hz). Unequivocal H
assignments were made with the aid of 2D-COSY (1H/1H) and
NOESY spectra (phase sensitive experiment, mixing time of 800
ms), while 13C assignments were made on the basis of 2D-HSQC
(1H/13C, delay for the one bond J C/H couplings was optimised at
147 Hz) and HMBC (delays for one bond and long-range J C/H
couplings were optimised at 147 and 7 Hz, respectively) experi-
ments. All the 2D spectra were acquired using the standard Bruker
microprograms. Elemental Analysis: Microanalytical laboratory of
the Department of Organic Chemistry, University of Debrecen. Ϫ
Preparative thin-layer chromatography: Merck or Riedel silica gel
60 DGF254. Ϫ Column chromatography: Merck silica gel 60 with
hexane/acetone (7:3 v/v) as eluent. Starting materials 1aϪf and 4a,d
were synthesised according to known procedures.[1,11Ϫ16] Dimethyl-
dioxirane (as an acetone solution) was prepared as described[17] and
its peroxide content was determined iodometrically.
Diastereomeric Mixture (35:65) of α,β:γ,δ-Diepoxycinnamylidene-
acetophenone (3a)
1
Major Isomer: H NMR: δ ϭ 3.15 (dd, J ϭ 1.9 and 4.5 Hz, 1 H,
H-γ), 3.30 (dd, J ϭ 1.9 and 4.5 Hz, 1 H, H-β), 3.87 (d, J ϭ 1.9 Hz,
1 H, H-δ), 4.33 (d, J ϭ 1.9 Hz, 1 H, H-α), 7.21Ϫ7.32 (m, 5 H, H-
2,3,4,5,6), 7.41Ϫ7.47 (m, 2 H, H-3Ј,5Ј), 7.57 (t, J ϭ 7.5 Hz, 1 H,
H-4Ј), 7.99 (d, J ϭ 7.6 Hz, 2 H, H-2Ј,6Ј). Ϫ 13C NMR: δ ϭ 54.2
(C-α), 56.7 (C-δ), 57.3 (C-β), 59.3 (C-γ), 125.38 (C-2,6), 128.03 (C-
2Ј,6Ј), 128.26 (C-3,4,5), 128.6 (C-3Ј,5Ј), 133.8 (C-4Ј), 134.9 (C-1Ј),
135.3 (C-1), 192.8 (CϭO).
1
Minor Isomer: H NMR: δ ϭ 3.23 (dd, J ϭ 2.0 and 3.2 Hz, 1 H,
(E,E)-2Ј-Hydroxy-4Ј-methylcinnamylideneacetophenone (4b): A 60%
H-γ), 3.38 (dd, J ϭ 2.0 and 3.2 Hz, 1 H, H-β), 3.89 (d, J ϭ 2.0 Hz,
aqueous solution of sodium hydroxide (160 mL) was added to a 1 H, H-δ), 4.33 (d, J ϭ 2.0 Hz, 1 H, H-α), 7.21Ϫ7.32 (m, 5 H, H-
methanolic solution (160 mL) of 2Ј-hydroxy-4Ј-methylaceto-
2,3,4,5,6), 7.41Ϫ7.47 (m, 2 H, H-3Ј,5Ј), 7.57 (t, J ϭ 7.5 Hz, 1 H,
phenone (4.0 mL, 30 mmol). This solution was allowed to cool to H-4Ј), 7.99 (d, J ϭ 7.6 Hz, 2 H, H-2Ј,6Ј). Ϫ 13C NMR: δ ϭ 53.7
room temperature and cinnamaldehyde (5.0 mL, 35 mmol) was (C-α), 55.8 (C-δ), 56.3 (C-β), 58.5 (C-γ), 125.40 (C-2,6), 128.06 (C-
then added. The reaction mixture was stirred at room temperature
2Ј,6Ј), 128.30 (C-4), 128.34 (C-3,5), 128.6 (C-3Ј,5Ј), 133.8 (C-4Ј),
for 20 h, then poured onto crushed ice and acidified with dilute 134.9 (C-1Ј), 135.5 (C-1), 192.9 (CϭO).
3216
Eur. J. Org. Chem. 2001, 3213Ϫ3219

Dimethyldioxirane Oxidation of (E,E)-Cinnamylideneacetophenones
Diastereomeric Mixture (36:64) of 4Ј-Methyl-α,β:γ,δ-diepoxycin-
SHORT COMMUNICATION
1 H, H-δ), 4.27 (d, J ϭ 1.9 Hz, 1 H, H-α), 7.26Ϫ7.30 (m, 2 H, H-
2,6), 7.31Ϫ7.38 (m, 3 H, H-3,4,5), 7.49 (d, J ϭ 8.7 Hz, 2 H, H-
namylideneacetophenone (3b)
1
Major Isomer: H NMR: δ ϭ 2.42 (s, 3 H, CH3), 3.17 (dd, J ϭ 2.0 3Ј,5Ј), 7.99 (d, J ϭ 8.7 Hz, 2 H, H-2Ј,6Ј). Ϫ 13C NMR: δ ϭ 54.7
and 4.6 Hz, 1 H, H-γ), 3.33 (dd, J ϭ 2.0 and 4.6 Hz, 1 H, H-β),
(C-α), 57.2 (C-δ), 57.6 (C-β), 59.6 (C-γ), 125.59 (C-2,6), 128.61 (C-
3.90 (d, J ϭ 2.0 Hz, 1 H, H-δ), 4.32 (d, J ϭ 2.0 Hz, 1 H, H-α), 3,4,5), 129.2 (C-3Ј,5Ј), 129.84 (C-2Ј,6Ј), 133.40 (C-1Ј), 135.3 (C-1),
7.25Ϫ7.35 (m, 7 H, H-2,3,3Ј,4,5,5Ј,6), 7.94 (d, J ϭ 8.3 Hz, 2 H, H-
140.8 (C-4Ј), 192.1 (CϭO).
1
2Ј,6Ј). Ϫ 13C NMR: δ ϭ 21.7 (CH3), 54.4 (C-α), 57.0 (C-δ), 57.5 Minor Isomer: H NMR: δ ϭ 3.28 (dd, J ϭ 2.0 and 2.9 Hz, 1 H,
(C-β), 59.7 (C-γ), 125.55 (C-2,6), 128.41 (C-2Ј,6Ј), 129.51 (C-3Ј,5Ј), H-γ), 3.46 (dd, J ϭ 2.0 and 2.9 Hz, 1 H, H-β), 3.95 (d, J ϭ 2.0 Hz,
128.52 (C-3,4,5), 132.71 (C-1Ј), 135.4 (C-1), 145.2 (C-4Ј), 192.7 1 H, H-δ), 4.30 (d, J ϭ 2.0 Hz, 1 H, H-α), 7.26Ϫ7.30 (m, 2 H, H-
(CϭO).
Minor Isomer: 1H NMR: δ ϭ 2.42 (s, 3 H, CH3), 3.26 (dd, J ϭ 2.0 3Ј,5Ј), 8.00 (d, J ϭ 8.7 Hz, 2 H, H-2Ј,6Ј). Ϫ 13C NMR: δ ϭ 54.2
and 3.1 Hz, 1 H, H-γ), 3.43 (dd, J ϭ 2.0 and 3.1 Hz, 1 H, H-β), (C-α), 56.3 (C-δ), 56.4 (C-β), 58.6 (C-γ), 125.62 (C-2,6), 128.74 (C-
3.94 (d, J ϭ 2.0 Hz, 1 H, H-δ), 4.33 (d, J ϭ 2.0 Hz, 1 H, H-α), 3,5), 128.68 (C-4), 129.2 (C-3Ј,5Ј), 129.81 (C-2Ј,6Ј), 133.43 (C-1Ј),
2,6), 7.31Ϫ7.38 (m, 3 H, H-3,4,5), 7.49 (d, J ϭ 8.7 Hz, 2 H, H-
7.25Ϫ7.35 (m, 7 H, H-2,3,3Ј,4,5,5Ј,6), 7.95 (d, J ϭ 8.3 Hz, 2 H, H-
2Ј,6Ј). Ϫ 13C NMR: δ ϭ 21.7 (CH3), 53.9 (C-α), 56.1 (C-δ), 56.4
(C-β), 58.8 (C-γ), 125.58 (C-2,6), 128.45 (C-2Ј,6Ј), 128.49 (C-3Ј,5Ј),
128.54 (C-4), 128.61 (C-3,5), 132.73 (C-1Ј), 135.7 (C-1), 145.2 (C-
4Ј), 192.5 (CϭO).
135.3 (C-1), 140.8 (C-4Ј), 192.3 (CϭO).
Diastereomeric Mixture (32:68) of 4Ј-Bromo-α,β:γ,δ-diepoxycinnam-
ylideneacetophenone (3f)
1
Major Isomer: H NMR: δ ϭ 3.18 (dd, J ϭ 1.8 and 4.6 Hz, 1 H,
H-γ), 3.35 (dd, J ϭ 1.8 and 4.6 Hz, 1 H, H-β), 3.92 (d, J ϭ 1.8 Hz,
1 H, H-δ), 4.27 (d, J ϭ 1.8 Hz, 1 H, H-α), 7.26Ϫ7.40 (m, 5 H, H-
2,3,4,5,6), 7.66 (d, J ϭ 8.5 Hz, 2 H, H-3Ј,5Ј), 7.92 (d, J ϭ 8.5 Hz,
2 H, H-2Ј,6Ј). Ϫ 13C NMR: δ ϭ 54.7 (C-α), 57.2 (C-δ), 57.7 (C-β),
59.6 (C-γ), 125.6 (C-2,6), 128.66 (C-3,4,5), 129.6 (C-4Ј), 129.89 (C-
2Ј,6Ј), 132.3 (C-3Ј,5Ј), 133.84 (C-1Ј), 135.3 (C-1), 192.4 (CϭO).
Diastereomeric Mixture (36:64) of 4Ј-Methoxy-α,β:γ,δ-diepoxycin-
namylidene-acetophenone (3c)
1
Major Isomer: H NMR: δ ϭ 3.18 (dd, J ϭ 1.9 and 4.5 Hz, 1 H,
H-γ), 3.34 (dd, J ϭ 1.9 and 4.5 Hz, 1 H, H-β), 3.87 (s, 3 H, OCH3),
3.91 (d, J ϭ 1.9 Hz, 1 H, H-δ), 4.29 (d, J ϭ 1.9 Hz, 1 H, H-α),
6.97 (d, J ϭ 8.9 Hz, 2 H, H-3Ј,5Ј), 7.25Ϫ7.29 (m, 2 H, H-2,6),
7.32Ϫ7.36 (m, 3 H, H-3,4,5), 8.04 (d, J ϭ 8.9 Hz, 2 H, H-2Ј,6Ј). Ϫ
13C NMR: δ ϭ 54.3 (C-α), 55.4 (OCH3), 57.0 (C-δ), 57.4 (C-β),
59.7 (C-γ), 114.02 (C-3Ј,5Ј), 125.53 (C-2,6), 128.2 (C-1Ј), 128.50 (C-
3,4,5), 130.7 (C-2Ј,6Ј), 135.4 (C-1), 164.2 (C-4Ј), 191.2 (CϭO).
1
Minor Isomer: H NMR: δ ϭ 3.28 (dd, J ϭ 1.8 and 2.5 Hz, 1 H,
H-γ), 3.46 (dd, J ϭ 1.8 and 2.5 Hz, 1 H, H-β), 3.95 (d, J ϭ 1.8 Hz,
1 H, H-δ), 4.29 (d, J ϭ 1.8 Hz, 1 H, H-α), 7.26Ϫ7.40 (m, 5 H, H-
2, -3, -4, -5, -6), 7.66 (d, J ϭ 8.5 Hz, 2 H, H-3Ј,5Ј), 7.92 (d, J ϭ
8.5 Hz, 2 H, H-2Ј,6Ј). Ϫ 13C NMR: δ ϭ 54.2 (C-α), 56.3 (C-δ),
56.4 (C-β), 58.6 (C-γ), 125.7 (C-2,6), 128.70 (C-4), 128.79 (C-3,5),
129.6 (C-4Ј), 129.94 (C-2Ј,6Ј), 132.3 (C-3Ј,5Ј), 133.87 (C-1Ј), 135.6
(C-1), 192.5 (CϭO).
1
Minor Isomer: H NMR: δ ϭ 3.26 (dd, J ϭ 2.0 and 3.1 Hz, 1 H,
H-γ), 3.43 (dd, J ϭ 2.0 and 3.1 Hz, 1 H, H-β), 3.87 (s, 3 H, OCH3),
3.94 (d, J ϭ 2.0 Hz, 1 H, H-δ), 4.31 (d, J ϭ 2.0 Hz, 1 H, H-α),
6.97 (d, J ϭ 8.8 Hz, 2 H, H-3Ј,5Ј), 7.25Ϫ7.29 (m, 2 H, H-2,6),
7.32Ϫ7.36 (m, 3 H, H-3,4,5), 8.04 (d, J ϭ 8.8 Hz, 2 H, H-2Ј,6Ј). Ϫ
13C NMR: δ ϭ 53.8 (C-α), 55.4 (OCH3), 56.1 (C-δ), 56.2 (C-β),
58.8 (C-γ), 113.99 (C-3Ј,5Ј), 125.56 (C-2,6), 128.3 (C-1Ј), 128.52 (C-
4), 128.58 (C-3,5), 130.8 (C-2Ј,6Ј), 135.7 (C-1), 164.2 (C-4Ј), 191.4
(CϭO).
Reactions of (E,E)-Cinnamylideneacetophenones 1c,d with One
Equivalent of Dimethyldioxirane According to the Procedure De-
scribed for the Diepoxides 3aϪf: The obtained mixtures were ana-
lysed by NMR spectroscopy and revealed the presence of the α,β-
monoepoxides 2c,d and diastereomeric mixtures of the α,β:γ,δ-di-
epoxides 3c,d in approximately 2:1 ratio. Here we present the main
characteristics of the monoepoxides 2c,d.
Diastereomeric Mixture (35:65) of 4Ј-Fluoro-α,β:γ,δ-diepoxycinnam-
ylideneacetophenone (3d)
Major Isomer: H NMR: δ ϭ 3.18 (dd, J ϭ 1.9 and 4.6 Hz, 1 H,
4Ј-Methoxy-α,β-epoxycinnamylideneacetophenone (2c): 1H NMR:
δ ϭ 3.73 (dd, J ϭ 1.9 and 7.9 Hz, 1 H, H-β), 4.27 (d, J ϭ 1.9 Hz,
1 H, H-α), 6.03 (dd, J ϭ 7.9 and 16.0 Hz, 1 H, H-γ), 6.88 (d, J ϭ
16.0 Hz, 1 H, H-δ). Ϫ 13C NMR: δ ϭ 59.0 (C-α), 59.6 (C-β), 124.6
(C-γ), 135. 8 (C-1), 136.2 (C-δ), 191.4 (CϭO).
1
H-γ), 3.35 (dd, J ϭ 1.9 and 4.6 Hz, 1 H, H-β), 3.92 (d, J ϭ 1.9 Hz,
1 H, H-δ), 4.28 (d, J ϭ 1.9 Hz, 1 H, H-α), 7.19 (dd, JH-F ϭ 8.5 Hz
and JH-H ϭ 8.8 Hz, 2 H, H-3Ј,5Ј), 7.27Ϫ7.30 (m, 2 H, H-2,6),
7.34Ϫ7.39 (m, 3 H, H-3,4,5), 8.09 (dd, J ϭ 2.2 and 8.8 Hz, 2 H,
H-2Ј,6Ј). Ϫ 13C NMR: δ ϭ 54.7 (C-α), 57.2 (C-δ), 57.6 (C-β), 59.7
(C-γ), 116.2 (d, JC-F ϭ 24.8 Hz, C-3Ј,5Ј), 125.6 (C-2,6), 128.6 (C-
3,4,5), 131.2 (d, JC-F ϭ 9.4 Hz, C-2Ј,6Ј), 131.6 (d, JC-F ϭ 2.6 Hz,
C-1Ј), 135.7 (C-1), 166.3 (d, JC-F ϭ 291.5 Hz, C-4Ј), 191.6 (CϭO).
4Ј-Fluoro-α,β-epoxycinnamylideneacetophenone (2d): 1H NMR: δ ϭ
3.74 (dd, J ϭ 1.8 and 7.9 Hz, 1 H, H-β), 4.26 (d, J ϭ 1.8 Hz, 1 H,
H-α), 6.03 (dd, J ϭ 7.9 and 15.9 Hz, 1 H, H-γ), 6.90 (d, J ϭ
15.9 Hz, 1 H, H-δ). Ϫ 13C NMR: δ ϭ 59.3 (C-α), 59.8 (C-β), 124.2
(C-γ), 135. 7 (C-1), 136.7 (C-δ), 191.8 (CϭO).
1
Minor Isomer: H NMR: δ ϭ 3.28 (dd, J ϭ 2.0 and 3.0 Hz, 1 H,
H-γ), 3.46 (dd, J ϭ 2.0 and 3.0 Hz, 1 H, H-β), 3.95 (d, J ϭ 2.0 Hz,
1 H, H-δ), 4.30 (d, J ϭ 2.0 Hz, 1 H, H-α), 7.19 (dd, JH-F ϭ 8.5 Hz
and JH-H ϭ 8.8 Hz, 2 H, H-3Ј,5Ј), 7.27Ϫ7.30 (m, 2 H, H-2,6),
7.34Ϫ7.39 (m, 3 H, H-3,4,5), 8.11 (dd, J ϭ 2.3 and 8.8 Hz, 2 H,
H-2Ј,6Ј). Ϫ 13C NMR: δ ϭ 54.2 (C-α), 56.3 (C-δ), 56.4 (C-β), 58.7
(C-γ), 116.1 (d, JC-F ϭ 24.8 Hz, C-3Ј,5Ј), 125.7 (C-2,6), 128.7
(C-4), 128.8 (C-3,5), 131.3 (d, JC-F ϭ 11.1 Hz, C-2Ј,6Ј), 131.7 (d,
JC-F ϭ 3.4 Hz, C-1Ј), 135.4 (C-1), 166.3 (d, JC-F ϭ 291.5 Hz,
C-4Ј), 191.8 (CϭO).
Reactions of (E,E)-2Ј-Hydroxycinnamylideneacetophenones 4aϪd
With Dimethyldioxirane According to the Procedure Described for
the Preparation of the Diepoxides 3aϪf: The NMR analysis of the
reaction mixtures revealed the presence of the γ,δ-monoepoxides
5aϪd and the α,β,γ,δ-diepoxides 6aϪd. Here we only consider the
assignments unequivocally made for these diepoxides 6aϪd. These
mixtures were analysed by preparative silica gel thin layer chroma-
tography (eluent: 1:1 mixture of light petroleum ether/dichlorome-
thane), leading to the isolation of the γ,δ-monoepoxides 5aϪd and
the coumaranone derivatives 7aϪd.
Diastereomeric Mixture (33:67) of 4Ј-Chloro-α,β:γ,δ-diepoxycin-
namylideneacetophenone (3e)
1
Major Isomer: H NMR: δ ϭ 3.18 (dd, J ϭ 1.9 and 4.6 Hz, 1 H,
2Ј-Hydroxy-γ,δ-epoxycinnamylideneacetophenone (5a): 1H NMR:
H-γ), 3.35 (dd, J ϭ 1.9 and 4.6 Hz, 1 H, H-β), 3.92 (d, J ϭ 1.9 Hz, δ ϭ 3.63 (ddd, J ϭ 0.5, 1.6 and 6.2 Hz, 1 H, H-γ), 3.90 (d, J ϭ
Eur. J. Org. Chem. 2001, 3213Ϫ3219 3217

´
A. Levai, A. M. S. Silva, J. A. S. Caveleiro, T. Patonay, V. L. M. Silva
SHORT COMMUNICATION
1.6 Hz, 1 H, H-δ), 7.09 (dd, J ϭ 6.2 and 15.1 Hz, 1 H, H-β), 6.93
(ddd, J ϭ 1.1, 7.2 and 8.1 Hz, 1 H, H-5Ј), 7.02 (dd, J ϭ 1.1 and
(C-3Ј), 120.8 (C-5Ј), 125.6 (C-2,6), 129.2 (C-6Ј), 135.3 (C-1), 149.5
(C-4Ј), 162.6 (C-2Ј), 196.6 (CϭO).
1
8.5 Hz, 1 H, H-3Ј), 7.31Ϫ7.42 (m, 5 H, H-2,3,4,5,6), 7.40 (d, J ϭ Minor Isomer: H NMR: δ ϭ 2.34 (s, 3 H, CH3), 3.28 (dd, J ϭ 1.9
15.1 Hz, 1 H, H-α), 7.51 (ddd, J ϭ 1.6, 7.2 and 8.5 Hz, 1 H, H-4Ј), and 2.8 Hz, 1 H, H-γ), 3.49 (dd, J ϭ 1.9 and 2.8 Hz, 1 H, H-β),
7.82 (dd, J ϭ 1.6 and 8.1 Hz, 1 H, H-6Ј), 12.55 (s, 1 H, 2Ј-OH). Ϫ 3.94 (d, J ϭ 1.9 Hz, 1 H, H-δ), 4.35 (d, J ϭ 1.9 Hz, 1 H, H-α),
13C NMR: δ ϭ 61.1 (C-γ), 61.8 (C-δ), 118.6 (C-3Ј), 119.0 (C-5Ј),
11.83 (s, 1 H, 2Ј-OH). Ϫ 13C NMR: δ ϭ 21.9 (CH3), 52.9 (C-α),
119.4 (C-1Ј), 125.3 (C-α), 125.5 (C-2,6), 128.7 (C-3,5), 128.8 (C-4), 56.2 (C-δ), 56.6 (C-β), 58.5 (C-γ), 125.4 (C-2,6), 135.9 (C-1), 149.6
129.9 (C-6Ј), 135.9 (C-1), 136.8 (C-4Ј), 144.2 (C-β), 163.6 (C-2Ј), (C-4Ј), 163.2 (C-2Ј), 196.7 (CϭO).
193.0 (CϭO).
Diastereomeric Mixture (60:40) of 5Ј-Fluoro-2Ј-hydroxy-α,β:γ,δ-di-
2Ј-Hydroxy-4Ј-methyl-γ,δ-epoxycinnamylideneacetophenone
(5b):
epoxycinnamylidene-acetophenone (6c)
1H NMR: δ ϭ 2.37 (s, 3 H, CH3), 3.62 (dd, J ϭ 1.7 and 6.0 Hz, 1
H, H-γ), 3.90 (d, J ϭ 1.7 Hz, 1 H, H-δ), 6.83 (br. s, 1 H, H-3Ј),
6.74 (dd, J ϭ 1.4 and 8.2 Hz, 1 H, H-5Ј), 7.06 (dd, J ϭ 6.0 and
15.3 Hz, 1 H, H-β), 7.30Ϫ7.42 (m, 5 H, H-2,3,4,5,6), 7.37 (d, J ϭ
15.3 Hz, 1 H, H-α), 7.70 (d, J ϭ 8.2 Hz, 1 H, H-6Ј), 12.62 (s, 1 H,
2Ј-OH). Ϫ 13C NMR: δ ϭ 22.0 (CH3), 61.1 (C-γ), 61.8 (C-δ), 115.9
(C-1Ј), 118.6 (C-3Ј), 120.4 (C-5Ј), 124.1 (C-α), 124.2 (C-2,6), 127.3
(C-3,5), 127.4 (C-4), 129.8 (C-6Ј), 134.6 (C-1), 147.7 (C-β), 148.6
(C-4Ј), 163.8 (C-2Ј), 192.3 (CϭO).
1
Major Isomer: H NMR: δ ϭ 3.20 (dd, J ϭ 1.8 and 4.4 Hz, 1 H,
H-γ), 3.41 (dd, J ϭ 1.8 and 4.4 Hz, 1 H, H-β), 3.93 (d, J ϭ 1.7 Hz,
1 H, H-δ), 4.29 (d, J ϭ 1.7 Hz, 1 H, H-α), 11.52 (s, 1 H, 2Ј-OH).
Ϫ
13C NMR: δ ϭ 53.8 (C-α), 57.3 (C-δ), 58.29 (C-β), 59.4 (C-γ),
158.9 (C-2Ј), 196.9 (d, JC-F ϭ 2.9 Hz, CϭO).
1
Minor Isomer: H NMR: δ ϭ 3.31 (dd, J ϭ 1.9 and 2.2 Hz, 1 H,
H-γ), 3.52 (dd, J ϭ 2.0 and 2.2 Hz, 1 H, H-β), 3.96 (d, J ϭ 1.9 Hz,
1 H, H-δ), 4.31 (d, J ϭ 2.0 Hz, 1 H, H-α), 11.55 (s, 1 H, 2Ј-OH).
Ϫ
13C NMR: δ ϭ 53.4 (C-α), 56.5 (C-δ), 56.9 (C-β), 59.33 (C-γ),
158.9 (C-2Ј), 197.1 (d, JC-F ϭ 2.9 Hz, CϭO).
5Ј-Fluoro-2Ј-hydroxy-γ,δ-epoxycinnamylideneacetophenone (5c): 1H
NMR: δ ϭ 3.64 (dd, J ϭ 0.60, 1.8 and 6.0 Hz, 1 H, H-γ), 3.90 (d,
J ϭ 1.8 Hz, 1 H, H-δ), 6.99 (dd, JH-F ϭ 4.6 Hz and JH-H ϭ 9.2 Hz,
1 H, H-3Ј), 7.12 (dd, J ϭ 6.0 and 15.1 Hz, 1 H, H-β), 7.26 (ddd,
JH-F ϭ 8.9 Hz and JH-H ϭ 3.1 and 9.2 Hz, 1 H, H-3Ј), 7.31Ϫ7.42
(m, 5 H, H-2,3,4,5,6), 7.35 (d, J ϭ 15.1 Hz, 1 H, H-α), 7.48 (dd,
JH-F ϭ 8.9 Hz and JH-H ϭ 3.1 Hz, 1 H, H-6Ј), 12.29 (s, 1 H, 2Ј-
Diastereomeric Mixture (63:37) of 5Ј-Chloro-2Ј-hydroxy-α,β:γ,δ-di-
epoxycinnamylidene-acetophenone (6d)
1
Major Isomer: H NMR: δ ϭ 3.20 (dd, J ϭ 1.7 and 4.4 Hz, 1 H,
H-γ), 3.42 (dd, J ϭ 1.7 and 4.4 Hz, 1 H, H-β), 3.94 (d, J ϭ 1.7 Hz,
1 H, H-δ), 4.31 (d, J ϭ 1.9 Hz, 1 H, H-α), 6.99 (d, J ϭ 8.9 Hz, 1
H, H-3Ј), 7.27Ϫ7.39 (m, 5 H, H-2,3,4,5,6), 7.48 (dd, J ϭ 2.4 and
8.9 Hz, 1 H, H-4Ј), 7.90 (d, J ϭ 2.4 Hz, 1 H, H-6Ј), 11.68 (s, 1 H,
2Ј-OH). Ϫ 13C NMR: δ ϭ 53.6 (C-α), 57.2 (C-δ), 58.3 (C-β), 59.3
(C-γ), 119.06 (C-1Ј), 120.35 (C-3Ј), 124.2 (C-5Ј), 125.6 (C-2,6),
135.1 (C-1), 137.38 (C-4Ј), 161.0 (C-2Ј), 196.8 (CϭO).
OH). Ϫ 13C NMR: δ ϭ 60.9 (C-γ), 61.9 (C-δ), 114.7 (d, JC-F
23.5 Hz, C-6Ј), 118.8 (d, JC-F ϭ 6.2 Hz, C-1Ј), 119.9 (d, JC-F
ϭ
ϭ
7.2 Hz, C-3Ј), 124.4 (d, JC-F ϭ 23.7 Hz, C-4Ј), 124.8 (C-α), 125.5
(C-2,6), 128.7 (C-3,5), 128.8 (C-4), 135.9 (C-1), 145.2 (C-β), 154.8
(d, JC-F ϭ 238.7 Hz, C-5Ј), 159.8 (d, JC-F ϭ 1.1 Hz, C-2Ј), 192.2
(d, JC-F ϭ 2.9 Hz, CϭO).
1
Minor Isomer: H NMR: δ ϭ 3.31 (dd, J ϭ 1.9 and 2.2 Hz, 1 H,
H-γ), 3.53 (dd, J ϭ 2.0 and 2.2 Hz, 1 H, H-β), 3.96 (d, J ϭ 1.9 Hz,
1 H, H-δ), 4.33 (d, J ϭ 2.0 Hz, 1 H, H-α), 6.96 (d, J ϭ 8.7 Hz, 1
H, H-3Ј), 7.27Ϫ7.39 (m, 5 H, H-2,3,4,5,6), 7.43 (dd, J ϭ 2.4 and
8.7 Hz, 1 H, H-4Ј), 7.91 (d, J ϭ 2.4 Hz, 1 H, H-6Ј), 11.71 (s, 1 H,
2Ј-OH). Ϫ 13C NMR: δ ϭ 53.2 (C-α), 56.4 (C-δ), 56.9 (C-β), 58.3
(C-γ), 119.09 (C-1Ј), 120.32 (C-3Ј), 124.2 (C-5Ј), 125.5 (C-2,6),
135.4 (C-1), 137.38 (C-4Ј), 161.0 (C-2Ј), 197.0 (CϭO).
1
5Ј-Chloro-2Ј-hydroxy-γ,δ-epoxycinnamylideneacetophenone (5d): H
NMR: δ ϭ 3.65 (dd, J ϭ 1.5 and 5.9 Hz, 1 H, H-γ), 3.91 (d, J ϭ
1.5 Hz, 1 H, H-δ), 6.98 (d, J ϭ 8.9 Hz, 1 H, H-3Ј), 7.13 (dd, J ϭ
5.9 and 15.0 Hz, 1 H, H-β), 7.31Ϫ7.42 (m, 5 H, H-2,3,4,5,6), 7.32
(d, J ϭ 15.0 Hz, 1 H, H-α), 7.45 (dd, J ϭ 2.6 and 8.9 Hz, 1 H, H-
4Ј), 7.78 (d, J ϭ 2.6 Hz, 1 H, H-6Ј), 12.46 (s, 1 H, 2Ј-OH). Ϫ 13C
NMR: δ ϭ 60.9 (C-γ), 62.0 (C-δ), 120.0 (C-1Ј), 120.2 (C-3Ј), 123.7
(C-5Ј), 124.6 (C-α), 125.6 (C-2,6), 128.7 (C-3,5), 128.8 (C-4), 129.1
(C-6Ј), 135.8 (C-1), 136.6 (C-4Ј), 145.4 (C-β), 162.1 (C-2Ј), 192.1
(CϭO).
Diastereomeric Mixture (58:42) of 2-(γ-Phenyl-α-hydroxy-β,γ-
epoxypropyl)coumaranone (7a)
1
Major Isomer: H NMR: δ ϭ 3.38 (dd, J ϭ 2.1 and 4.4 Hz, 1 H,
H-2Ј), 4.08 (d, J ϭ 2.1 Hz, 1 H, H-3Ј), 4.42Ϫ4.44 (m, 1 H, H-1Ј),
4.74 (d, J ϭ 2.4 Hz, 1 H, H-2), 7.06Ϫ7.21 (m, H-5 and H-7),
7.30Ϫ7.41 (m, H-2ЈЈ, -3ЈЈ, -4ЈЈ, -5ЈЈ, -6ЈЈ), 7.59Ϫ7.70 (m, H-4 and
H-6). Ϫ 13C NMR: δ ϭ 56.4 (C-3Ј), 61.4 (C-2Ј), 69.6 (C-1Ј), 84.41
(C-2), 113.4 (C-7), 121.4 (C-9), 122.3 (C-5), 124.27 (C-4), 125.7 (C-
2ЈЈ, -6ЈЈ), 128.0Ϫ129.1 (C-3ЈЈ, -4ЈЈ, -5ЈЈ), 136.2 (C-1ЈЈ), 138.29 (C-
6), 173.5 (C-8), 199.5 (CϭO).
Diastereomeric Mixture (88:12) of 2Ј-Hydroxy-α,β:γ,δ-diepoxycin-
namylideneacetophenone (6a)
1
Major Isomer: H NMR: δ ϭ 3.21 (dd, J ϭ 1.8 and 4.8 Hz, 1 H,
H-γ), 3.43 (dd, J ϭ 1.7 and 4.8 Hz, 1 H, H-β), 3.94 (d, J ϭ 1.8 Hz,
1 H, H-δ), 4.40 (d, J ϭ 1.7 Hz, 1 H, H-α), 6.77 (dd, J ϭ 1.2 and
7.94 (d, J ϭ 1.3 and 8.1 Hz, 1 H, H-6Ј), 11.77 (s, 1 H, 2Ј-OH). Ϫ
13C NMR: δ ϭ 53.5 (C-α), 57.3 (C-δ), 58.2 (C-β), 59.5 (C-γ), 162.6
(C-2Ј), 197.3 (CϭO).
1
Minor Isomer: H NMR: δ ϭ 3.25 (dd, J ϭ 2.1 and 3.5 Hz, 1 H,
H-2Ј), 4.10 (d, J ϭ 2.1 Hz, 1 H, H-3Ј), 4.42Ϫ4.44 (m, 1 H, H-1Ј),
4.78 (d, J ϭ 4.2 Hz, 1 H, H-2), 7.06Ϫ7.21 (m, H-5 and H-7),
7.30Ϫ7.41 (m, H-2ЈЈ, -3ЈЈ, -4ЈЈ, -5ЈЈ, -6ЈЈ), 7.59Ϫ7.70 (m, H-4 and
H-6). Ϫ 13C NMR: δ ϭ 55.5 (C-3Ј), 60.3 (C-2Ј), 69.8 (C-1Ј), 84.37
(C-2), 113.5 (C-7), 122.6 (C-5), 122.4 (C-9), 124.31 (C-4), 125.6 (C-
2ЈЈ, -6ЈЈ), 128.0Ϫ129.1 (C-3ЈЈ, -4ЈЈ, -5ЈЈ), 136.6 (C-1ЈЈ), 138.33 (C-
6), 173.5 (C-8), 199.5 (CϭO).
1
Minor Isomer: H NMR: δ ϭ 3.31 (dd, J ϭ 2.0 and 2.7 Hz, 1 H,
H-γ), 3.53 (dd, J ϭ 2.1 and 2.7 Hz, 1 H, H-β), 3.98 (d, J ϭ 2.0 Hz,
1 H, H-δ), 4.42 (d, J ϭ 2.1 Hz, 1 H, H-α), 11.85 (s, 1 H, 2Ј-OH).
Diastereomeric Mixture (86:14) of 2Ј-Hydroxy-4Ј-methyl-α,β:γ,δ-di-
epoxycinnamylideneacetophenone (6b)
1
Major Isomer: H NMR: δ ϭ 2.33 (s, 3 H, CH3), 3.19 (dd, J ϭ 1.9
and 4.3 Hz, 1 H, H-γ), 3.39 (dd, J ϭ 1.9 and 4.3 Hz, 1 H, H-β),
Diastereomeric Mixture (55:45) of 6-Methyl-2-(γ-phenyl-α-hydroxy-
3.91 (d, J ϭ 1.9 Hz, 1 H, H-δ), 4.34 (d, J ϭ 1.9 Hz, 1 H, H-α), β,γ-epoxypropyl)coumaranone (7b)
1
6.77 (dd, J ϭ 1.2 and 8.2 Hz, 1 H, H-5Ј), 6.82 (br. s, 1 H, H-3Ј),
Major Isomer: H NMR: δ ϭ 2.45 (s, 3 H, CH3), 3.36 (dd, J ϭ 2.1
7.79 (d, J ϭ 8.2 Hz, 1 H, H-6Ј), 11.80 (s, 1 H, 2Ј-OH). Ϫ 13C NMR: and 4.4 Hz, 1 H, H-2Ј), 4.07 (d, J ϭ 2.1 Hz, 1 H, H-3Ј), 4.42 (dd,
δ ϭ 22.0 (CH3), 53.3 (C-α), 57.1 (C-δ), 57.9 (C-β), 59.4 (C-γ), 118.6 J ϭ 2.4 and 4.4 Hz, 1 H, H-1Ј), 4.73 (d, J ϭ 2.4 Hz, 1 H, H-2),
3218
Eur. J. Org. Chem. 2001, 3213Ϫ3219

Dimethyldioxirane Oxidation of (E,E)-Cinnamylideneacetophenones
SHORT COMMUNICATION
6.95 (br. d, J ϭ 7.9 Hz, H-5), 6.99 (br. s, 1 H, H-7), 7.27Ϫ7.42 (m, istry Research Unit), for funding. The technical assistance of Mrs.
5 H, H-2ЈЈ, -3ЈЈ, -4ЈЈ, -5ЈЈ, -6ЈЈ), 7.56 (d, J ϭ 7.9 Hz, 1 H, H-4). Ϫ M. Nagy is highly appreciated.
13C NMR: δ ϭ 22.6 (CH3), 56.3 (C-3Ј), 61.5 (C-2Ј), 69.5 (C-1Ј),
84.6 (C-2), 113.4 (C-7), 119.0 (C-9), 124.0 and 123.9 (C-4 and C-
5), 125.7 (C-2ЈЈ, -6ЈЈ), 128.36, 128.43 and 128.5 (C-3ЈЈ, -4ЈЈ, -5ЈЈ),
136.3 (C-1ЈЈ), 150.5 (C-6), 174.0 (C-8), 198.8 (CϭO).
[1]
M. Scholtz, Ber. Dtsch. Chem. Ges. 1895, 28, 1726Ϫ1733.
E. Weitz, A. Scheffer, Ber. Dtsch. Chem. Ges. 1921, 54,
2327Ϫ2344.
[2]
[3]
´
M. E. Lasterra-Sanchez, U. Felfer, P. Mayon, S. M. Roberts,
Minor Isomer: 1H NMR: δ ϭ 2.42 (s, 3 H, CH3), 3.24 (dd, J ϭ 2.1
and 3.7 Hz, 1 H, H-2Ј), 4.10 (d, J ϭ 2.1 Hz, 1 H, H-3Ј), 4.39 (dd,
J ϭ 3.7 and 4.3 Hz, 1 H, H-1Ј), 4.76 (d, J ϭ 4.3 Hz, 1 H, H-2),
6.90 (br. d, J ϭ 7.7 Hz, H-5), 6.99 (br. s, 1 H, H-7), 7.27Ϫ7.42 (m,
5 H, H-2ЈЈ, -3ЈЈ, -4ЈЈ, -5ЈЈ, -6ЈЈ), 7.53 (d, J ϭ 7.7 Hz, 1 H, H-4). Ϫ
13C NMR: δ ϭ 22.6 (CH3), 55.4 (C-3Ј), 60.4 (C-2Ј), 69.8 (C-1Ј),
84.5 (C-2), 113.5 (C-7), 118.3 (C-9), 123.9 and 123.8 (C-4 and C-
5), 125.7 (C-2ЈЈ, -6ЈЈ), 128.36, 128.43 and 128.5 (C-3ЈЈ, -4ЈЈ, -5ЈЈ),
136.2 (C-1ЈЈ), 150.6 (C-6), 173.5 (C-8), 198.5 (CϭO).
A. R. Thornton, C. J. Todd, J. Chem. Soc., Perkin Trans. 1
1996, 343Ϫ348; J. V. Allen, S. Bergeron, M. J. Griffiths, S.
Mukkerjee, S. M. Roberts, N. M. Williamson, L. E. Wu, J.
Chem. Soc., Perkin Trans. 1 1998, 3171Ϫ3179.
G. B. Marini-Bettolo, Gazz. Chim. Ital. 1942, 72, 201Ϫ208.
J. A. S. Cavaleiro, J. Elguero, M. L. Jimeno, A. M. S. Silva,
Chem. Lett. 1991, 445Ϫ446; A. M. S. Silva, D. C. G. A. Pinto,
J. A. S. Cavaleiro, Tetrahedron Lett. 1994, 35, 5899Ϫ5902; D.
C. G. A. Pinto, A. M. S. Silva, J. A. S. Cavaleiro, Tetrahedron
Lett. 1994, 35, 9459Ϫ9460; D. C. G. A. Pinto, A. M. S. Silva,
J. A. S. Cavaleiro, J. Heterocycl. Chem. 1996, 33, 1887Ϫ1893;
A. M. S. Silva, D. C. G. A. Pinto, H. R. Tavares, J. A. S. Cava-
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2031Ϫ2038.
A. M. S. Silva, J. A. S. Cavaleiro, J. Elguero, Liebigs Ann./
Recueil 1997, 2065Ϫ2068.
W. Adam, L. Hadjiarapoglou, B. Nestler, Tetrahedron Lett.
1990, 31, 331Ϫ334; W. Adam, L. Hadjiarapoglou, Chem. Ber.
1990, 123, 2077Ϫ2079; W. Adam, L. Hadjiarapoglou, A.
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B. Harden, Jr., J. Org. Chem. 1993, 58, 7615Ϫ7618.
[4]
[5]
Diastereomeric Mixture (71:29) of 5-Fluoro-2-(γ-phenyl-α-hydroxy-
β,γ-epoxypropyl)coumaranone (7c)
1
Major Isomer: H NMR: δ ϭ 3.37 (dd, J ϭ 2.1 and 4.3 Hz, 1 H,
H-2Ј), 3.99 (d, J ϭ 2.1 Hz, 1 H, H-3Ј), 4.42Ϫ4.45 (m, 1 H, H-1Ј),
4.79 (d, J ϭ 2.3 Hz, 1 H, H-2), 7.16Ϫ7.47 (m, 8 H, H-2ЈЈ, -3ЈЈ, -
4ЈЈ, -4, -5ЈЈ, -6ЈЈ, -6, -7).
[6]
[7]
1
Minor Isomer: H NMR: δ ϭ 3.24 (dd, J ϭ 2.0 and 3.9 Hz, 1 H,
H-2Ј), 3.96 (d, J ϭ 2.0 Hz, 1 H, H-3Ј), 4.42Ϫ4.45 (m, 1 H, H-1Ј),
4.78 (d, J ϭ 3.1 Hz, 1 H, H-2), 7.16Ϫ7.47 (m, 8 H, H-2ЈЈ, -3ЈЈ, -
4ЈЈ, -4, -5ЈЈ, -6ЈЈ, -6, -7).
[8]
´
W. Adam, L. Hadjiarapoglou, A. Levai, Synthesis 1992,
´
´
436Ϫ438; W. Adam, J. Halasz, A. Levai, C. Nemes, T. Patonay,
G. Toth, Liebigs Ann. Chem. 1994, 795Ϫ803; C. Nemes, A.
Levai, T. Patonay, G. Toth, S. Boros, J. Halasz, W. Adam, D.
Golsch, J. Org. Chem. 1994, 59, 900Ϫ905; W. Adam, J. Halasz,
Z. Jambor, A. Levai, C. Nemes, T. Patonay, G. Toth, J. Chem.
Soc., Perkin Trans. 1 1996, 395Ϫ400; W. Adam, J. Halasz, Z.
Jambor, A. Levai, C. Nemes, T. Patonay, G. Toth, Monatsh.
Diastereomeric Mixture (51:49) of 5-Chloro-2-(γ-phenyl-α-hydroxy-
β,γ-epoxypropyl)coumaranone (7d)
´
´
´
´
1
Major Isomer: H NMR: δ ϭ 3.36 (dd, J ϭ 2.1 and 4.5 Hz, 1 H,
´
H-2Ј), 4.04 (d, J ϭ 2.1 Hz, 1 H, H-3Ј), 4.39Ϫ4.42 (m, 1 H, H-1Ј),
4.74 (d, J ϭ 2.1 Hz, 1 H, H-2), 7.11 (d, J ϭ 7.6 Hz, 1 H, H-7),
7.27Ϫ7.33 (m, 5 H, H-2ЈЈ, -3ЈЈ, -4ЈЈ, -5ЈЈ, -6ЈЈ), 7.53 (dd, J ϭ 2.3
and 7.6 Hz, 1 H, H-6), 7.62 (d, J ϭ 2.3 Hz, 1 H, H-7). Ϫ 13C NMR:
δ ϭ 56.0 (C-3Ј), 61.3 (C-2Ј), 69.6 (C-1Ј), 85.5 (C-2), 114.7 (C-7),
122.43 (C-9), 123.6 (C-4), 125.57, 125.69 and 125.71 (C-2ЈЈ, -6ЈЈ),
128.36Ϫ129.96 (C-3ЈЈ, -4ЈЈ, -5ЈЈ), 136.1 (C-1ЈЈ), 138.0 (C-6), 171.8
(C-8), 198.5 (CϭO).
´
´
´
´
´
´
´
´
´
Chem. 1996, 127, 683Ϫ690; W. Adam, A. Levai, I. Y. Merour,
C. Nemes, T. Patonay, Synthesis 1997, 268Ϫ270.
[9]
W. Adam, J. Bialas, L. Hadjiarapoglou, T. Patonay, Synthesis
´
´ ´
1992, 49Ϫ51; T. Patonay, A. Levai, C. Nemes, T. Tımar, G.
´
Toth, W. Adam, J. Org. Chem. 1996, 61, 5375Ϫ5383; A. J.
Burke, W. I. OЈSullivan, Tetrahedron 1997, 53, 8491Ϫ9500.
1
Minor Isomer: H NMR: δ ϭ 3.24 (dd, J ϭ 2.2 and 3.5 Hz, 1 H,
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
´
A. M. Lluch, F. Sanchez-Baeza, A. Messeguer, C. Fusco, R.
H-2Ј), 4.05 (d, J ϭ 2.2 Hz, 1 H, H-3Ј), 4.39Ϫ4.42 (m, 1 H, H-1Ј),
4.82 (d, J ϭ 2.3 Hz, 1 H, H-4), 7.14 (d, J ϭ 8.0 Hz, 1 H, H-7),
7.27Ϫ7.33 (m, 5 H, H-2ЈЈ, -3ЈЈ, -4ЈЈ, -5ЈЈ, -6ЈЈ), 7.59 (dd, J ϭ 2.4
and 8.0 Hz, 1 H, H-6), 7.60 (d, J ϭ 2.4 Hz, 1 H, H-7). Ϫ 13C NMR:
δ ϭ 55.8 (C-3Ј), 60.0 (C-2Ј), 69.9 (C-1Ј), 85.6 (C-2), 114.7 (C-7),
122.40 (C-9), 123.7 (C-4), 125.57, 125.69 and 125.71 (C-2ЈЈ, -6ЈЈ),
128.36Ϫ129.96 (C-3ЈЈ, -4ЈЈ, -5ЈЈ), 136.0 (C-1ЈЈ), 138.0 (C-6), 171.3
(C-8), 197.7 (CϭO).
Curci, Tetrahedron 1993, 49, 6299Ϫ6308.
M. Scholtz, A. Wiedemann, Ber. Dtsch. Chem. Ges. 1903, 36,
845Ϫ854.
H. Bauer, E. Breit, Ber. Dtsch. Chem. Ges. 1906, 39,
19Ϫ16Ϫ1921.
´
D. C. G. A. Pinto, A. M. S. Silva, A. Levai, J. A. S. Cavaleiro,
T. Patonay, J. Elguero, Eur. J. Org. Chem. 2000, 2593Ϫ2599.
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1 1974, 1383Ϫ1388.
U. S. Cheema, K. C. Gulati, K. Venkataraman, J. Chem. Soc.
1932, 925Ϫ933.
E. T. Oganesyan, A. V. Simonyan, V. S. Cherevatyi, Khim.
Pharm. Zh. 1988, 22, 1104Ϫ1108.
W. Adam, J. Bialas, L. Hadjiarapoglou, Chem. Ber. 1991, 124,
2377Ϫ2377.
Acknowledgments
Sincere thanks are expressed to the Hungarian Scientific Research
Fund (Grant No. OTKA T-029171), to the European Union (Pro-
ject No. COST D12/019/98) and to the University of Aveiro and
Received March 8, 2001
ˆ
‘‘Fundaca˜o para a Ciencia e Tecnologia’’, Portugal (Organic Chem-
¸
[O01106]
Eur. J. Org. Chem. 2001, 3213Ϫ3219
3219