4,4′-Bis(dichloroiodo)biphenyl and 3-(dichloroiodo)benzoic acid: New recyclable hypervalent iodine reagents for vicinal halomethoxylation of unsaturated compounds

Article abstract of DOI:10.1055/s-2004-831175

4,4′-Bis(dichloroiodo)biphenyl and 3-(dichloroiodo)benzoic acid are convenient recyclable hypervalent iodine reagents for vicinal chloromethoxylation or iodomethoxylation of unsaturated compounds. The reactivity of these reagents in the reaction of vicinal halomethoxylation is generally similar to dichloroiodobenzene and the advantage of their use is that the reduced forms of these reagents can be easily separated from the reaction mixture and reused for the regeneration of the reagents.

Full text of DOI:10.1055/s-2004-831175

PAPER
2289
4,4¢-Bis(dichloroiodo)biphenyl and 3-(Dichloroiodo)benzoic Acid: New
Recyclable Hypervalent Iodine Reagents for Vicinal Halomethoxylation of
Unsaturated Compounds
4
, 4
¢
-Bis(dichloroiodo)
b
e
iphenyl an
h
d 3-(Dichlor
m
A
cidan S. Yusubov,*a,b Larisa A. Drygunova,b Viktor V. Zhdankinc
a
b
c
Received 12 May 2004; revised 14 June 2004
Dedicated to Professor N. S. Zefirov on his 70th anniversary
can be easily separated from reaction mixtures in almost
quantitative yields and reused for the regeneration of re-
agents 2 and 4.
Abstract: 4,4¢-Bis(dichloroiodo)biphenyl
and
3-(dichloro-
iodo)benzoic acid are convenient recyclable hypervalent iodine re-
agents for vicinal chloromethoxylation or iodomethoxylation of
unsaturated compounds. The reactivity of these reagents in the re-
action of vicinal halomethoxylation is generally similar to dichloro-
iodobenzene and the advantage of their use is that the reduced forms
of these reagents can be easily separated from the reaction mixture
and reused for the regeneration of the reagents.
4,4¢-Bis(dichloroiodo)biphenyl (2) was prepared by satu-
rating a solution of 4,4¢-diiodobiphenyl (1) in CHCl3 with
gaseous chlorine for one hour at room temperature under
stirring. Product 2 was isolated in high yield as a yellow,
stable and non-explosive microcrystalline solid; it can be
stored for several weeks in a refrigerator in dark. Chlorine
content in 2 was analyzed by iodometric titration.
Key words: hypervalent iodine, halogens, electrophilic additions,
oxidations, alkenes
Cl2
Hypervalent iodine reagents have emerged as reagents of
choice for various synthetically useful oxidative transfor-
mations.1 The commonly used reagents, such as dichloro-
iodobenzene, iodosylbenzene, (diacetoxy)iodobenzene,
and [hydroxy(tosyloxy)iodo]benzene, are based on the
oxidized forms of iodobenzene. The reactions of these re-
agents with organic substrates lead to iodobenzene as the
byproduct, which is difficult to recover and reuse because
of the high volatility and solubility in organic solvents.
Several research groups have tried to improve the iodo-
benzene-based hypervalent iodine reagents by developing
their polymer-supported analogs.2,3 In particular, it has
been demonstrated that poly(diacetoxyiodo)styrene
shows the reactivities similar to (diacetoxy)iodobenzene
and can be utilized as the environmentally benign replace-
ment for hypervalent iodine reagents.3 Despite the utility
of the polymer-supported reagents, they still have several
drawbacks. These reagents require a multistep prepara-
tion, they have lower reactivity compared to the corre-
sponding monomeric analogs, and, moreover, the
repeated use of these polymers leads to significant degra-
dation due to the benzylic oxidation of the polystyrene
chain. We wish to report the preparation and reactivity of
new recyclable nonpolymeric hypervalent iodine chlo-
rides 2 and 4. Reagents 2 and 4 can be conveniently pre-
pared by simple chlorination of the commercially
available iodides 1 and 3 (Scheme 1), their reactivity is
similar to the practically useful dichloroiodobenzene,1
and the products of their reactions with organic substrates
I
I
Cl2I
ICl2
CHCl3, r.t.
2 93%
CO2H
1
I
CO2H
Cl2I
Cl2
CHCl3, r.t.
4 95%
3
Scheme 1
Compound 2 is a convenient chlorinating reagent and its
reduced form, 4,4¢-diiodobiphenyl (1), is practically insol-
uble at room temperature in organic solvents that are com-
monly used as reaction media (hydrocarbons, alcohols,
carbonic acids etc.). The low solubility allows convenient
separation of 4,4¢-diiodobiphenyl from reaction products
by simple filtration and reuse for the regeneration of re-
agent 2. At the same time, 4,4¢-diiodobiphenyl (1) has ex-
cellent solubility in CHCl3, which is important for the
preparation of 2 by chlorination of 1 under homogeneous
conditions. Reagent 2 has several obvious advantages
over the polymer-supported hypervalent iodine reagents:
(i) it is significantly cheaper and easy to prepare from a
readily available precursor, (ii) reagent 2 has high recycla-
bility without degradation loss, (iii) it has high loading ef-
ficiency, and (iv) analytical control of the quality of the
reagent can be conveniently performed by iodometric ti-
tration.
Synthetic utility of reagent 2 was investigated in the reac-
tions of chloro- and iodomethoxylation of unsaturated
compounds.4,5 In particular, in the reaction of 2 with sty-
rene derivatives 5a–c in MeOH the products of electro-
SYNTHESIS 2004, No. 14, pp 2289–2292
x
x.
x
x
.
2
0
0
4
Advanced online publication: 19.08.2004
DOI: 10.1055/s-2004-831175; Art ID: M03304SS
© Georg Thieme Verlag Stuttgart · New York

2290
M. S. Yusubov et al.
PAPER
philic chloromethoxylation 6a–c were isolated in 60–70% phenyl-1-butene (5g), besides the anticipated iodo-
yield. In addition, the reaction mixture contained small methoxylation product, iodochlorination products were
amount (2–7%) of vicinal dichlorides. A similar reaction obtained in significant amounts (Scheme 5). Two frac-
of reagent 2 with alkenes in the presence of iodine in tions were isolated by column chromatography of the re-
MeOH led to the products of iodomethoxylation 7a,b,d,e action mixture: the first one was a non-separable mixture
in 60–90% yields, but not the chloromethoxylation prod- of two regioisomers 7g and 10 of iodomethoxylation reac-
ucts (Scheme 2).
tion in the ratio of 2:1 with total yield of 43%, and the sec-
ond fraction was non-separable mixture of
iodochlorination products 11 and 12 (1:1 ratio) with total
a
Ph Cl R2
MeOH
+
1
yield of 29%.
R1
OMe
Ph
R1
R2
6a-c
+
2
I2, MeOH
OMe
Cl
I
+
R
+ 2
R
R
Ph
R1
I
R2
– 1
5a-e
I
I2, MeOH
OMe
7g
+
1
10
5g
OMe
I
R
R
R
R
R
1 = R2 = H (5a, 6a, 7a)
+
R
R = CH2CH2Ph
R
7a,b,d,e
1 = Ph, R2 = H (5b, 6b, 7b)
1 = H, R2 = Ph (5c, 6c)
1 = Me, R2 = H (5d, 7d)
1 = H, R2 = Me (5e, 7e)
I
Cl
11
12
Scheme 5
Scheme 2
We assume that compounds 10–12 are formed via a mech-
Under similar conditions, the reaction of reagent 2 with anism involving the intermediate formation of alkylaryl-
(1S)-(+)-3-carene (5f) in the presence of iodine afforded iodonium ion, similarly to the previously reported
product 7f that was isolated by column chromatography in reactions of KICl2 and KICl4 with alkenes, resulting in the
22% yield (Scheme 3).
formation of the regioisomeric vicinal iodochloroal-
kanes.5
OMe
Table 1 Halomethoxylation of Unsaturated Compounds with 4,4¢-
Bis(dichloroiodo)biphenyl (2) and 3-(Dichloroiodo)benzoic Acid (4)
I
I2, MeOH
+ 2
+
1
Substrate Reagent/Conditionsa Time (h) Product
Yield (%)b
5a
5a
5b
5b
5c
5d
5e
5f
2/MeOH
2
6a
7a
6b
7b
6c
7d
7e
7f
62
75
66
90
57
85
82
22
61
5f
7f
I2/2/MeOH
2/MeOH
0.5
10
0.5
2
Scheme 3
Reaction of phenylacetylene 8 with 2 in MeOH produced
2,2-dichloro-1,1-dimethoxy-1-phenylethane (9) in 61%
yield (Scheme 4).
I2/2/MeOH
2/MeOH
I2/2/MeOH
I2/2/MeOH
I2/2/MeOH
2/MeOH
0.5
0.5
0.5
3
Ph Cl Cl
MeOH
Ph
+
+ 2
1
MeO
OMe
8
9
8
9
Scheme 4
5g
I2/2/MeOH
0.5
7g + 10
11 + 12
43
29
Comparison of these results with the previously reported
reactions of dichloroiodobenzene with alkenes under sim-
ilar conditions4 leads to a conclusion that the reactivity of
reagent 2 in the reactions of vicinal halomethoxylation of
unsaturated compounds is generally similar to dichloro-
iodobenzene. However, the reaction of 2 with styrene 5a
the presence of iodine in MeOH was different from the re-
action of dichloroiodobenzene.4 In this case, in addition to
the iodomethoxylation product, a small amount (2%) of 1-
(1-chloro-2-iodoethyl)benzene was obtained as a product
of vicinal iodochlorination. Likewise, in the reaction of 4-
5a
5b
5d
5g
I2/4/MeOH
I2/4/MeOH
I2/4/MeOH
I2/4/MeOH
0.25
0.25
0.25
0.25
7a
7b
7d
65
85
93
7g + 10
11 + 12
59
24
a All reactions were carried out at r.t.
b Yields of products isolated after column chromatography.
Synthesis 2004, No. 14, 2289–2292 © Thieme Stuttgart · New York

PAPER
4,4′-Bis(dichloroiodo)biphenyl and 3-(Dichloroiodo)benzoic Acid
2291
under stirring. The precipitate was filtered, washed with cold CHCl3
and dried in darkness to give 2 as a yellow solid; yield: 2.55 g
(93%); mp 156–158 °C (dec).
The second chlorinating reagent, 3-(dichloroiodo)benzoic
acid (4), can be conveniently prepared by the chlorination
of the commercially available 3-iodobenzoic acid (3)
(Scheme 1). Reagent 4 is specifically attractive due to the
fact that its reduced form 3 can also be easily separated
from the products of chlorination. It is possible due to the
high solubility of 3-iodobenzoic acid (3) and its salts in
aqueous solutions. Therefore the recovery of 3 from the
reaction mixture can be successfully performed by the
treatment with 5% aqueous solution of sodium bicarbon-
ate.
Product 2 was analyzed by iodometric titration: calcd for
C12H8I2Cl4: Cl, 26.31; found: Cl, 27.02. NMR spectra were impos-
sible to obtain due to insolubility of 2 in CHCl3.
3-(Dichloroiodo)benzoic Acid (4); Typical Procedure
An excess of chlorine was bubbled through a solution of 3-iodoben-
zoic acid (3, 1.24 g, 5.0 mmol) in CHCl3 (80 mL) for 1 h at r.t. under
stirring. The precipitate was filtered, rinsed with cold CHCl3 and
dried in darkness to give 4 as a yellow solid; yield: 1.51 g (95%);
mp 183–185 °C (dec) (Lit.6 mp 187-189 °C).
We investigated the reactivity of 4 in iodomethoxylation
reaction of alkenes. The expected products 7a,b,d were
Chloromethoxylation of Alkenes with Reagent 2 in MeOH;
isolated in good yields from the reactions of 4 with alk- General Procedure
Reagent 2 (0.3 g, 0.55 mmol) was added to a solution of alkene 5a–
enes 5 in MeOH in the presence of iodine (Scheme 6). It
should be noted that the reaction of 4-phenyl-1-butene
(5g) with 4 and iodine in MeOH afforded methoxyiodides
7g and 10, as well as the regioisomeric iodochlorination
products 11 and 12, in the same ratios, as in the reaction
of reagent 2.
c (1.0 mmol) in MeOH (3.0 mL) and the reaction mixture was
stirred at r.t. for a period of time shown in Table 1. MeOH was re-
moved on a rotary evaporator; then hexane (3.0 mL) was added and
the precipitate of 4,4¢-diiodobiphenyl (1) was filtered and addition-
ally washed with hexane (1.0 mL) on the filter. The hexane solution
was concentrated and the resulting products 6a–c were isolated by
column chromatography on silica gel. Compounds 6a–c were iden-
tified by comparison of their spectra with literature data.4a Chlo-
romethoxylation of phenylacetylene (8, 1.0 mmol) was performed
similarly using 2 (1.1 mmol) in MeOH (3.0 mL). Product 9 was
identified by comparison of its spectra with literature data.4a
R1
I
I2, MeOH
Ph
Ph
+ 3
+ 4
R1
MeO
7a,b,d
5a,b,d
Iodomethoxylation of Alkenes with Reagent 2 and Iodine in
MeOH; General Procedure
Scheme 6
Reagent 2 (0.3 g, 0.55 mmol) was added to a solution of iodine (0.28
g, 1.1 mmol) in MeOH (4.0 mL) and the mixture was stirred for 10
min at r.t. The resulting mixture was added through a filter to a so-
lution of alkene 5a,b,d,e (2.0 mmol) in MeOH (1.0 mL). The reac-
tion mixture was stirred at r.t. for a period of time shown in Table 1.
The mixture was treated with 5% aq Na2S2O3 (20 mL), extracted by
Et2O (2 × 30 mL), washed with water and sat. solution of NaCl, and
dried with Na2SO4. Et2O was evaporated and the residue was treated
In conclusion, 4,4¢-bis(dichloroiodo)biphenyl (2) and 3-
(dichloroiodo)benzoic acid (4) are convenient recyclable
hypervalent iodine reagents for vicinal halomethoxylation
of unsaturated compounds. These reagents combine the
properties of the common polyvalent iodine compounds
and their polymer-supported analogs. The reactivity of
these reagents in the reaction of vicinal halomethoxyla- as described in the previous procedure. In the reaction of 5b, the fi-
nal product 7b precipitated from the reaction mixture in MeOH in
the form of rhombic crystals and was separated by filtration. Prod-
ucts 7a,b,d were identified by comparison of their spectra with lit-
the reduced forms of these reagents can be easily separat-
erature data.4b
tion of unsaturated compounds is generally similar to
dichloroiodobenzene and the advantage of their use is that
ed from the products of halogenation of organic sub-
strates.
1-Iodo-2-methoxy-4-phenylbutane (7g)
1H NMR (300 MHz, CDCl3): d = 1.87 (m, 2 H, 3-CH2), 2.63 (m, 2
H, 4-CH2), 2.95 (m, 1 H, 2-CH), 3.21 (m, 2 H, 1-CH2), 3.32 (s, 3 H,
OCH3), 7.12–7.25(m, 5 Harom.).
All melting points were determined using a Boetius melting point
apparatus and are uncorrected. IR spectra were recorded on a Bruk-
13C NMR (75 MHz, CDCl3): d = 9.98 (CH2I), 31.15 (4-CH2), 36.31
(3-CH2), 56.92 (OCH3), 78.50 (2-CH), 125.84, 128.32, 142.06
(Carom).
MS (EI): m/z (%) = 290 [M]+ (< 1), 185 [C3H6IO]+ (19), 163 [M –
I]+ (18), 131 [C10H11]+ (100), 117 [C9H9]+ (10), 105 [C8H9]+ (8), 91
[C7H7]+ (69), 77 [C6H5]+ (6), 58 [C3H6O]+ (8).
er Vector-22 spectrophotometer. H NMR and 13C NMR spectra
1
were recorded on a Bruker AM-300 NMR spectrometer (300.13
MHz and 75.47 MHz) and DRX 500 (500 MHz and 125 MHz) us-
ing TMS as internal standard. Chemical shifts are reported in ppm.
GC–MS spectra were obtained using gas chromatograph equipped
with quadrupole mass-spectrometer Hewlett Packard 5890/II as de-
tector (EI, 70 eV). High resolution EI mass spectra (EI, 70 eV) were
recorded on Finnigan MAT 8200 mass spectrometer. Microanaly-
ses were carried out using 1106 Carlo Erba CHNS-O analyzer.
Flash column chromatography was performed on silica gel (L40/
100 mm; purchased from Chemapol) or aluminum oxide (neutral,
Brockmann II; purchased from Roanal). TLC was performed on sil-
ica gel plates Sorbfil (made in Russia).
Anal. Calcd for C11H15IO: C, 45.54; H, 5.21; I, 43.74. Found: C,
45.35; H, 5.34; I, 43.47.
2-Iodo-1-methoxy-4-phenylbutane (10)
1H NMR (300 MHz, CDCl3): d = 2.05 (m, 2 H, 3-CH2), 2.81 (m, 2
H, 4-CH2), 3.29 (s, 3 H, OCH3), 3.58 (m, 1 H, 2-CH), 4.05 (m, 2 H,
1-CH2), 7.12–7.25 (m, 5 Harom.).
13C NMR (75 MHz, CDCl3): d = 33.05 (CHI), 35.12 (4-CH2), 37.90
(3-CH2), 58.48 (OCH3), 78.11 (C1H), 126.05, 128.36, 142.06
(Carom).
4,4¢-Bis(dichloroiodo)biphenyl (2); Typical Procedure
An excess of chlorine was bubbled through a solution of 4,4¢-di-
iodobiphenyl (1, 2.0 g, 5.0 mmol) in CHCl3 (80 mL) for 1 h at r.t.
Synthesis 2004, No. 14, 2289–2292 © Thieme Stuttgart · New York

2292
M. S. Yusubov et al.
PAPER
Iodomethoxylation of Alkenes with Reagent 4 and Iodine in
MS (EI): m/z (%) = 290 [M]+ (6), 131 [C10H11]+ (100), 115 [C9H7]+
(5), 105 [C8H9]+ (6), 91 [C7H7]+ (44), 77 [C6H5]+ (3), 65 (8), 45
[C2H5O]+ (11).
MeOH; General Procedure
Iodine (0.27 g, 1.05 mmol) was added to the solution of reagent 4
(0.35 g, 1 mmol) in MeOH (4.0 mL) and the mixture was stirred for
5 min at r.t. The resulting mixture was added to a solution of alkene
(2.0 mmol) in MeOH (2.0 mL) and stirred at r.t. for 10 min. The re-
action mixture was added to 5% aq NaHCO3 (30 mL), treated with
5% aq Na2S2O3 (20 mL), extracted by Et2O (2 × 30 mL), the Et2O
extract was washed with water and sat. solution of NaCl, and dried
with Na2SO4. The aqueous solution that was left after extraction,
was acidified with HNO3 and the white precipitate of sodium salt of
3-iodobenzoic acid was separated by filtration and used for regen-
eration of reagent 4. The Et2O solution was concentrated and the
residue was dissolved in hexane (3.0 mL) and separated by column
chromatography on silica gel using hexane as the eluent. The isolat-
ed compounds 7a,b,d were identified by comparison of their spectra
with literature data.4
Anal. Calcd for C11H15IO: C, 45.54; H, 5.21; I, 43.74. Found: C,
45.35; H, 5.34; I, 43.47.
2-Chloro-1-iodo-4-phenylbutane (11)
1H NMR (300 MHz, CDCl3): d = 1.97 (m, 2 H, 3-CH2), 2.68 (m, 2
H, 4-CH2), 3.36 (m, 2 H, 1-CH2), 3.80 (m, 1 H, 2-CH), 7.15–7.18
(m, 5 Harom.).
MS (EI): m/z (%) = 294, 296 [M]+ (11), 167, 169 [M – I]+ (3), 131
[C10H11]+ (58), 91 [C7H7]+ (100), 65 [C5H5]+ (10).
Anal. Calcd for C10H12ClI: C, 40.78; H, 4.11; Cl, 12.04; I, 43.08.
Found: C, 40.54; H, 4.34; Cl, 12.83, I, 42.97.
1-Chloro-2-iodo-4-phenylbutane (12)
1H NMR (300 MHz, CDCl3): d = 2.32 (m, 2 H, 3-CH2), 2.84 (m, 2
H, 4-CH2), 3.49 (m, 1 H, 2-CH), 4.07 (m, 2 H, 1-CH2), 7.15–7.18
(m, 5 Harom.).
Acknowledgment
MS (EI): m/z (%) = 294/296 [M]+ (15), 167, 169 [M – I]+ (7), 131
MSY thanks Ministry of Education (grant N E02-5.0-176) for the fi-
nancial support of this work. VVZ is thankful to the National Sci-
ence Foundation (NSF/CHE-0353541) for partial support of this
research.
[C10H11]+ (32), 91 [C7H7]+ (100), 65 [C5H5]+ (8).
Anal. Calcd for C10H12ClI: C, 40.78; H, 4.11; Cl, 12.04, I, 43.08.
Found: C, 40.54; H, 4.34; Cl, 12.83; I, 42.97.
1-Iodo-2-methoxy-1-phenylpropane (7e)
References
1H NMR (300 MHz, CDCl3): d = 1.71 (d, J = 6.9 Hz, 3 H, CH3), 3.27
(s, 3 H, OCH3), 4.19 (d, J = 4.8 Hz, 1 H, CHOCH3), 4.25 (m, 1 H,
CHI), 7.18–7.30 (m, 5 Harom.).
(1) (a) Varvoglis, A. Hypervalent Iodine in Organic Synthesis;
Academic Press: London, 1997. (b) Hypervalent Iodine
Chemistry, Topics in Current Chemistry, Vol. 224; Wirth,
T., Ed.; Springer-Verlag: Berlin / Heidelberg, 2003.
(c) Zhdankin, V. V.; Stang, P. J. Chem. Rev. 2002, 102,
2523. (d) Wirth, T.; Hirt, U. H. Synthesis 1999, 1271.
(e) Skulski, L. Molecules 2000, 5, 1331.
13C NMR (75 MHz, CDCl3): d = 22.54 (CH3), 31.37 (CHI), 57.96
(OCH3), 88.01 (CHOCH3), 127.47, 128.20, 128.32, 138.06 (Carom).
MS (EI): m/z (%) = 276 [M]+ (< 1), 149 [M – I]+ (25), 121 [C8H9O]+
(100), 117 [C9H9]+ (12), 91 [C7H7]+ (12), 77 [C6H5]+ (10).
(2) Togo, H.; Sakuratania, K. Synlett 2002, 1966.
(3) (a) Tohma, H.; Takizawa, S.; Maegawa, T.; Kita, Y. Angew.
Chem. Int. Ed. 2000, 39, 1306. (b) Tohma, H.; Morioka, H.;
Takizawa, S.; Arisawa, M.; Kita, Y. Tetrahedron 2001, 57,
345. (c) Tohma, H.; Maegawa, T.; Kita, Y. Arkivoc 2003,
62. (d) Tohma, H.; Maegawa, T.; Kita, Y. Synlett 2003, 723.
(e) Togo, H.; Nogami, G.; Yokoyama, M. Synlett 1998, 534.
(f) Togo, H.; Abe, S.; Nogami, G.; Yokoyama, M. Bull.
Chem. Soc. Jpn. 1999, 72, 2351. (g) Togo, H.; Sakuratania,
K. Synthesis 2003, 21. (h) Abe, S.; Sakuratania, K.; Togo,
H. J. Org. Chem. 2001, 66, 6174. (i) Ley, S. V.; Thomas, A.
W.; Finch, H. J. Chem. Soc., Perkin Trans. 1 1999, 669.
(j) Ley, S. V.; Schucht, O.; Thomas, A. W.; Murray, P. J. J.
Chem. Soc., Perkin Trans. 1 1999, 1251. (k) Baxendale, I.
R.; Lee, A.-L.; Ley, S. V. J. Chem. Soc., Perkin Trans. 1
2002, 1850. (l) Baxendale, I. R.; Ley, S. V.; Piutti, C.
Angew. Chem. Int. Ed. 2002, 41, 2194.
Anal. Calcd for C10H13IO: C, 43.50; H, 4.75; I, 45.96. Found: C,
43.12; H, 4.68; I, 45.40.
(1S,3R,4R,6R)-4-Iodo-3-methoxy-3,7,7-trimethylbicyc-
lo[4.1.0]heptane (7f)
IR (film): 1107 (COCH3), 599 (CI) cm–1.
1H NMR (500 MHz, CDCl3): d = 0.45 (ddd, J1 = 9.9 Hz, J2 = 8.3 Hz,
J3 = 0.7 Hz, 1 H, 6-H), 0.71 (ddd, J1 = 10.1 Hz, J2 = 9.9 Hz, J3 = 4.4
Hz, 1 H, 1-H), 0.86, 0.93 (2 × s, 6 H, 8-H, 9-H), 1.19 (d, J = 0.7 Hz,
3 H, 10-H), 1.31 (ddq, J1 = 14.2 Hz, J2 = 4.4 Hz, J3 = 0.7 Hz, 1 H,
2-H), 2.01 (dd, J1 = 14.2 Hz, J2 = 10.1 Hz, 1 H, 2-H), 2.37 (ddd,
J1 = 15.0 Hz, J2 = 6.9 Hz, J3 = 0.7 Hz, 1 H, 5-H), 2.54 (ddd, J1 = 15.0
Hz, J2 = 11.6 Hz, J3 = 8.3 Hz, 1 H, 5-H); 3.06 (s, 3 H, OCH3); 3.98
(dd, J1 = 11.6 Hz, J2 = 6.9 Hz, 1 H, 4-H).
13C NMR (125 MHz, CDCl3): d = 15.10 (8-C); 17.45 (7-C); 19.56
(1-C), 19.62 (6-C), 21.98 (10-C), 26.90 (5-C), 28.43 (9-C), 33.86
(2-C), 41.08 (4-C), 48.28 (OCH3), 73.88 (3-C).
MS (EI): m/z (%) = 294 [M]+ (< 1), 167 [M – I]+ (6), 166 [M – HI]+
(19), 151 (22), 142 (41), 135 (26), 106 (53), 119 (44), 93 (100), 85
(39), 67 (33), 59 (23), 55 (24), 43 (68).
(4) (a) Yusubov, M. S.; Yusubova, R. Y.; Filimonov, V. D.; Chi,
K.-W. Zh. Org. Chem. 2002, 38, 944. (b) Yusubov, M. S.;
Yusubova, R. Y.; Filimonov, V. D.; Chi, K.-W. Synth.
Commun. 2004, 34, 443.
(5) Zefirov, N. S.; Sereda, G. A.; Sosonuk, S. E.; Zyk, N. V.;
Likhomanova, T. I. Synthesis 1995, 1359.
HRMS (EI): m/z [M
–
HI]+ calcd C11H18O: 166.13244;
found:166.13576.
(6) Obeid, N.; Skulski, L. Molecules 2001, 6, 869; available at
URL: http://www.mdpi.org/molecules/papers/
61100869.pdf.
Synthesis 2004, No. 14, 2289–2292 © Thieme Stuttgart · New York