Highly regioselective cleavages and iodinations of cyclic ethers utilizing SmI2

Article abstract of DOI:10.1021/jo020179r

Various functionalized cyclic ethers such as oxiranes, oxetanes, and tetrahydrofurans have been prepared, and the regiochemistry of their ring opening with samarium diiodide and acyl chloride or anhydride has been investigated. Alkyl-substituted oxetane 5 and tetrahydrofurans 1 and 2 show almost no regioselectivity. However, high regioselectivities from the branched cyclic ethers (3, 8, 9, and 10) containing ethereal or hydroxyl moieties have been observed. This is probably the result of the bidentate chelated species between samarium and oxygen.

Full text of DOI:10.1021/jo020179r

been utilized for the cleavage of ethers but are not always
satisfactory for complex molecules containing sensitive
functionalities, and frequently long reaction times are
required, or for the lack of regioselectivity in the cleavage
of nonsymmetrical cyclic systems.14
High ly Regioselective Clea va ges a n d
Iod in a tion s of Cyclic Eth er s Utilizin g Sm I2
Doo Won Kwon and Yong Hae Kim*
Department of Chemistry, Center for Molecular Design and
Synthesis, Korea Advanced Institute of Science and
Technology, Daejon, 305-701, Korea
Nucleophilic acylations of esters,15 ketones, or alde-
hydes16 with SmI2 have been demonstrated. Ring opening
of THF with samarium(III) triiodide-acid chloride17 and
ring opening of cyclic ethers with samarium(II) diiodide-
BF3‚Et2O-benzene-HMPA18 have been reported. On the
basis of our previous works on the reactivity of SmI2,19
we have found that small-membered ring ethers can be
cleaved with SmI2 and acyl chloride or anhydride in
tetrahydropyran as a solvent to afford iodinated esters
in a regioselective manner. Herein, we describe a facile
acylative cleavage of functionalized cyclic ethers utilizing
SmI2 and acylating reagents. The cleavage reactions were
investigated focusing on whether the regioselectivity
depends on the ring size and the functional groups
already attached (Scheme 1).
Kieseung Lee
Department of Chemistry, Woosuk University,
Chonbuk 565-701, Korea
kimyh@mail.kaist.ac.kr
Received March 14, 2002
Abstr a ct: Various functionalized cyclic ethers such as
oxiranes, oxetanes, and tetrahydrofurans have been pre-
pared, and the regiochemistry of their ring opening with
samarium diiodide and acyl chloride or anhydride has been
investigated. Alkyl-substituted oxetane 5 and tetrahydro-
furans 1 and 2 show almost no regioselectivity. However,
high regioselectivities from the branched cyclic ethers (3, 8,
9, and 10) containing ethereal or hydroxyl moieties have
been observed. This is probably the result of the bidentate
chelated species between samarium and oxygen.
A variety of functionalized epoxides, oxetanes, and
tetrahydrofuran derivatives were prepared. R-Substitut-
ed tetrahydrofurans 1-3 are commercially available. The
oxetanes were prepared by the reaction of dimethyloxo-
sulfonium methylide with epoxides or with carbonyl
compounds.20 The epoxides 8-10 were prepared by
m-CPBA oxidations of the corresponding olefin com-
pounds.
The cleavage of ethers is a versatile reaction in organic
synthesis, particularly in degradation or transformation
of natural products and polyfunctional molecules. Trans-
formations of cyclic ethers to haloesters1 are effective
methods for producing difunctional synthetic intermedi-
ates and are also important for the removal of ethereal
protecting groups.2 Since the protection of a hydroxyl
group as an acetate is frequently employed in the total
synthesis of complex natural products such as carbohy-
drates and macrolide antibiotics, a number of ether-
cleavage reactions have been developed.
Tetrahydrofuran reacted with acyl chlorides or acetic
anhydride in the presence of 2 equiv of SmI2 to afford
the corresponding iodinated esters in excellent yields
(entries 1-4). In the absence of acyl chloride, the reaction
did not proceed: for instance, THF and oxetane 6 were
inert toward SmI2 in the absence of acyl chloride, and
the starting substrates were recovered quantitatively.
Tetrahydrofuran 2 substituted with a methyl group at
the R-position (entry 6) or oxetane 5 substituted with a
phenyl group at the γ-position (entry 9) gave almost no
regioselectivity (1:1 (entry 6) or 5:4 (entry 9) in Table 1,
respectively). However, in contrast to the poor regiose-
lectivity from 2-methyltetrahydrofuran 2, the tetrahy-
drofurfuryl alcohol 3 resulted in extremely high regiose-
lectivity (>99:1, 70%, entry 7). The branched oxetane 6
containing a benzyl ether moiety at the â-position also
Lewis acids such as ZnCl2,3 FeCl3,4 Mo(CO)6,5 MoCl5,6
PdCl2(PPh3)2,7 CoCl2,8 NaI,9 lanthanide salts,10 Zn,11
graphite,12 and Al complexes13 have been used for cleav-
ages of ethers. A variety of other different reagents have
* To whom correspondence should be addressed. Phone: +82-42-
869-2818. Fax: +82-42-869-5818.
(1) (a) Bhatt, M. V.; Kulkarni, S. U. Synthesis 1983, 249. (b)
Maercker, A. Angew. Chem., Int. Ed. Engl. 1987, 26, 972.
(2) Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic
Synthesis, 3rd ed.; Wiley: New York, 1999; p 23.
(3) Cloke, J . B.; Pilgrim, F. J . J . Am. Chem. Soc. 1939, 61, 2667.
(4) Ganem, B.; Small, V. R., J r. J . Org. Chem. 1974, 39, 3728.
(5) Alper, H.; Huang, C.-C. J . Org. Chem. 1973, 38, 64.
(6) Guo, Q.; Miyaji, T.; Gao, G.; Hara, R.; Takahashi, T. J . Chem.
Soc., Chem. Commun. 2001, 1018.
(7) Pri-Bar, I.; Stille, J . K. J . Org. Chem. 1982, 47, 1215.
(8) Iqbal, J .; Srivastava. R. R. Tetrahedron 1991, 47, 3155.
(9) (a) Oku, A.; Harada, T.; Kita, K. Tetrahedron Lett. 1982, 23, 681.
(b) Mimero, P.; Saluzzo, C.; Amouroux, R. Tetrahedron Lett. 1994, 35,
1553.
(10) Taniguchi, Y.; Tanaka, S.; Kitamura, T.; Fujiwara, Y. Tetra-
hedron Lett. 1998, 39, 4559.
(11) Bhar, S.; Ranu, B. C. J . Org. Chem. 1995, 60, 745.
(12) Suzuki, Y.; Matsushima, M.; Kodomari, M. Chem. Lett. 1998,
319.
(13) Green, L.; Hemeon, I.; Singer, R. D. Tetrahedron Lett. 2000,
41, 1343.
(14) (a) Goldsmith, D. J .; Kennedy, E.; Campbell, R. G. J . Org. Chem.
1975, 40, 3571. (b) Yadav, V. K.; Fallis, A. G. J . Org. Chem. 1986, 51,
3372. (c) Guindon, Y.; Therien, M.; Girard, Y.; Yoakim, C. J . Org. Chem.
1987, 52, 1680.
(15) Machrouhi, F.; Namy, J .-L.; Kagan, H. B. Tetrahedron Lett.
1997, 38, 7183.
(16) (a) Collin, J .; Namy, J .-L.; Dallemer, F.; Kagan, H. B. J . Org.
Chem. 1991, 56, 3118. (b) Souppe, J .; Namy, J .-L.; Kagan, H. B.
Tetrahedron Lett. 1984, 25, 2869.
(17) Yu, Y.; Zhang, Y.; Ling, R. Synth. Commun. 1993, 23, 1973.
(18) Kang, H. Y.; Park, B. K.; Koh, H. Y. Bull. Korean Chem. Soc.
1997, 18, 1245.
(19) (a) Kim Y. H. Acc. Chem. Res. 2001, 34, 955. (b) Kim, S. M.;
Byun, I. S.; Kim, Y. H. Angew. Chem., Int. Ed. 2000, 39, 728. (c) Kim,
Y. H.; Park, H. S.; Chung, S. H. Synlett 1998, 1073. (d) Park, H. S.;
Lee, I. S.; Kwon, D. W.; Kim, Y. H. J . Chem. Soc., Chem. Commun.
1998, 2745.
(20) (a) Okuma, K.; Tanaka, Y.; Kaji, S.; Ohta, H. J . Org. Chem.
1983, 48, 5133. (b) Fitton, A. O.; Hill, J .; J ane, D. E.; Millar, R.
Synthesis 1987, 1140.
10.1021/jo020179r CCC: $22.00 © 2002 American Chemical Society
Published on Web 11/23/2002
9488
J . Org. Chem. 2002, 67, 9488-9491

freshly distilled over CaH2. Reactions were monitored by thin-
layer chromatography (TLC) analysis. NMR spectra were mea-
sured in CDCl3/TMS at 300 or 400 MHz (1H) and 100 MHz (13C).
1H NMR coupling constants are given in hertz. For column
chromatography, silica gel (230-400 mesh) was employed. Flash
column chromatography on silica gel (2 cm × 25 cm; solvent )
Et2O/n-hexane) was normally used for purification of the reaction
mixtures. Samarium diiodide was freshly prepared by the
reaction of diiodomethane with samarium metal powder (1.2
equiv) in THP under argon with vigorous stirring for 2 h. The
epoxides were commercially available or prepared by epoxidation
of the corresponding olefins.
Typ ica l P r oced u r e for th e Syn th esis of Oxeta n es (4). A
mixture of KOBu-t (1.12 g, 10 mmol) and trimethyloxosulfonium
iodide (2.2 g, 10 mmol) in dry t-BuOH (13 mL) was stirred
magnetically at 50 °C for 1 h. A solution of styrene oxide (0.6 g,
5 mmol) in dry t-BuOH (10 mL) was then added dropwise and
stirred for 3 days. The solvent was carefully evaporated under
reduced pressure, and water (30 mL) was added to the residual
suspension. The mixture was extracted with n-hexane, dried over
anhydrous MgSO4, and concentrated to give the crude product
4, which was purified by column chromatography to afford 4 as
a colorless oil (0.47 g, 3.5 mmol, 70%).
2-(3-Meth ylh exa -3,5-d ien yl)-oxeta n e (5). The same pro-
cedure described for compound 4 was carried out to give 5 as a
colorless oil (60%): 1H NMR (CDCl3) δ 7.30 (m, 5H), 4.83 (m,
1H), 4.68 (m, 1H), 4.52 (m, 1H), 2.64 (m, 3H), 2.35 (m, 1H), 2.15
(m, 1H), 1.98 (m, 1H); 13C NMR δ 141.5, 128.5, 128.3, 125.7,
81.9, 68.1, 39.5, 30.3, 27.4; HREIMS [M+] calcd for C11H14O,
162.1044; found, 162.1049.
2-Ben zyloxym eth yl-oxeta n e (6). The same procedure de-
scribed for compound 4 was carried out to give 6 as a colorless
oil (65%): 1H NMR (CDCl3) δ 7.32 (m, 5H), 4.96 (m, 1H), 4.63
(m, 4H), 3.66 (m, 2H), 2.63 (m, 2H); 13C NMR δ 137.7, 128.3,
127.6, 127.5, 81.2, 73.49, 73.44, 68.9, 23.8; HREIMS [M+] calcd
for C11H14O2, 178.09938; found, 178.0991.
SCHEME 1
gave regiospecific ring opening (∼100:0, entry 10). Thus,
the high regioselectivity appears to arise from the
intervention of a five-membered ring bidentate chelated
intermediate A, which might be formed by the strong
electrophilicity of samarium for the oxygen attached at
â-position (Scheme 2 and Figure 1). The oxetane 7
substituted with a benzyloxy group at the γ-position gave
relatively lower selectivity (4:1, entry 11) than that
(∼100:0) obtained from â-substituted 6 (entry 10). To
compare the substituent effect of benzyl group in 7, a
bulky tert-butyldimethylsilyloxy (TBDMS) moiety was
introduced instead of benzyl. In this case, the regiose-
lectivity decreased (a :b ) 2:1) probably due to a steric
hindrance of bulky TBDMS moiety in A′. The selective
cleavage may be influenced by the ring size of intermedi-
ates: high selectivity presumably arises from the five-
membered chelated ring A, but a lower selectivity (4:1)
may be caused by the six-membered chelated ring
intermediate A′ (Figure 2). The extremely high regiose-
lective cleavage (entries 7 and 10) is probably due to the
formation of a five-membered ring intermediate A that
arose due to the oxophilicity of samarium. All the
monosubstituted oxiranes 8-10 yielded only one regio-
isomer in excellent yields (entries 12-14) obtained by an
attack of iodide on the less substituted carbon atom of
the highly strained epoxide ring.
Although the precise mechanism of the acylative
cleavage is not clear, the reaction is presumably initiated
by formation of acyl radical 11 and then acylsamarium
species 12. The use of 1 equiv of SmI2 gave a low yield
(45%) of cleaved iodide product, but 2 equiv of SmI2
resulted in high yield (92%, entry 1), which might be
required for forming acyl radical 11 and then acylsa-
marium 12. Acylsamarium 12 interacts with cyclic ethers
to form an intermediate A or B depending on the
branched cyclic ethers being substituted at R-, â-, or
γ-positions. A strong electrophilicity of samarium toward
two oxygens may form A giving the corresponding iodide
products with extremely high regioselectivity by “a ”
attack. Simple interaction between samarium and an
oxygen of cyclic ethers having no substituent (substituted
with alkyl groups) forms B, which provided both “a ” and
“b” routes without giving high selectivity. Thus, the high
regioselectivity observed might arise from the complex-
ation of acylsamarium with cyclic ethers substituted with
a hydroxyl or ethereal moiety, where oxygen plays an
important role.
2-(2-Ben zyloxyeth yl)-oxeta n e (7). The same procedure
described for compound 4 was carried out to give 7 as a colorless
oil (63%): 1H NMR (CDCl3) δ 7.32 (m, 5H), 4.98 (m, 1H), 4.64
(m, 1H), 4.52 (m, 1H), 4.46 (s, 2H), 3.52 (m, 2H), 2.65 (m, 1H),
2.41 (m, 1H), 2.09 (m, 2H); 13C NMR δ 138.3, 128.3, 127.5, 127.4,
80.2, 73.0, 68.3, 65.9, 38.0, 27.5; HREIMS [M+] calcd for
C
12H16O2, 192.11503; found, 192.1151.
Typ ica l Rea ction for Clea va ges of Cyclic Eth er s (1a ).
To a solution of SmI2 (1.0 mmol) in THP (10 mL) were added
cyclic ether 1 (55 mg, 0.55 mmol) and acetyl chloride (39 mg,
0.5 mmol) in one portion. The mixture was stirred for 1 h under
argon at room temperature. The reaction was quenched with
saturated aqueous NH4Cl (5 mL). The reaction mixture was
diluted with Et2O (5 mL), and the organic layer was washed
with water. The aqueous phase was extracted with Et2O (2 ×
10 mL), and the combined organic layers were washed with
brine, dried over anhydrous MgSO4, and concentrated to give
the crude product, which was purified by column chromatogra-
phy (2 cm × 25 cm; eluent ) 1:1 Et2O/n-hexane) to afford 1a as
a yellow oil (117 mg, 87%): 1H NMR (CDCl3) δ 4.9 (m, 1H), 4.14
(m, 1H), 2.0 (s, 3H), 1.89 (d, J ) 6.4, 3H), 1.7 (m, 4H), 1.47 (d,
J ) 6.3, 3H); 13C NMR δ 170.7, 70.2, 69.7, 38.7, 38.3, 36.1, 35.8,
29.4, 28.8, 21.3, 20.0; HREIMS [M+] calcd for C8H15IO2, 270.0116;
found, 270.0124.
Acetic Acid 4-Iod o-1-m eth ylbu tyl Ester (2a ). The ratio of
1
2a and 2b was determined by H NMR analysis of the mixture
of 2a and 2b. The 2a and 2b were separated by column
chromatography (2 cm × 30 cm; eluent ) 1:20 ethyl acetate/
n-hexane). 2a : yellow oil (42%); 1H NMR (CDCl3) δ 4.91 (m, 1H),
3.15 (t, J ) 6.8, 2H), 1.99 (s, 3H), 1.88-1.55 (m, 4H), 1.21 (d, J
) 6.3, 3H); 13C NMR δ 170.5, 69.7, 36.6, 29.3, 21.2, 19.9, 6.1;
HREIMS [M+] calcd for C7H13IO2, 255.9960; found, 255.9968.
2b: yellow oil (42%); 1H NMR (CDCl3) δ 4.12 (m, 1H), 4.05 (t, J
) 6.1, 2H), 2.02 (s, 3H), 1.92 (d, J ) 6.9, 3H), 1.88-1.55 (m,
4H); 13C NMR δ 171.0, 63.4, 39.1, 29.0, 28.95, 28.90, 20.9;
HREIMS [M+] calcd for C7H13IO2, 255.9960; found, 255.9960.
Acet ic Acid 1-Hyd r oxym et h yl-4-iod o-bu t yl E st er (3a ).
The same procedure described for compound 1a was carried out
In summary, we have developed cleavage reactions of
cyclic ethers by the use of SmI2 based on chelation control
to obtain functionalized acylated iodide compounds with
both high regioselectivity and high chemical yields.
Exp er im en ta l Section
Gen er a l. All reactions were performed in oven-dried glass-
ware under argon using anhydrous solvents. THF was dried and
freshly distilled over sodium/benzophenone, and CH2Cl2 was
J . Org. Chem, Vol. 67, No. 26, 2002 9489

TABLE 1. Acyla tive Clea va ge of Cyclic Eth er s Usin g Sm I2
a
Isolated yield after column chromatography. Products were fully characterized by 1H NMR, 13C NMR, and HR mass spectrometry.
Determined by 1H NMR spectroscopy (see Experimental Section). c Only one isomer was detected and isolated.
b
1
to give 3a (70%) as the major product. 3a : yellow oil; H NMR
(CDCl3) δ 5.07 (m, 1H), 4.22 (dd, J ) 11.9, 3.5, 1H), 4.04 (dd, J
) 11.9, 6.3, 1H), 3.16 (t, J ) 6.7, 2H), 2.05 (s, 3H), 1.82-1.65
(m, 4H); 13C NMR δ 170.7, 70.3, 64.8, 31.6, 28.9, 21.0, 20.7, 5.6;
HREIMS [M+] calcd for C7H13IO3, 271.9909; found, 271.9892.
Ben zoic Acid 3-P h en ylp r op yl Ester (4b). The same pro-
cedure described for compound 1a was carried out to give
deiodinated product 4b (89%) as the sole product. 4b: yellow oil;
1H NMR (CDCl3) δ 8.0-7.1 (m, 10H), 4.35 (t, J ) 6.5, 2H), 2.8
(t, J ) 7.6, 2H), 2.1 (m, 2H); 13C NMR δ 166, 141, 132, 130, 129,
128.5, 128.4, 128.3, 126, 64.2, 32, 30; HREIMS [M+] calcd for
Acetic Acid 3-Iod o-1-p h en eth ylp r op yl Ester s (5a a n d
5b). The reaction gave a mixture of 5a and 5b whose ratio (5a :
5b ) 5:4) was determined by 1H NMR, and the compounds were
separated by column chromatography (2 cm × 25 cm; eluent )
1:2 Et2O/n-hexane) to give 5a (46%) and 5b (36%). 5a : yellow
oil; 1H NMR (CDCl3) δ 7.28 (m, 5H), 4.95 (m, 1H), 3.12 (m, 2H),
2.61 (m, 2H), 2.15 (m, 2H), 2.04 (s, 3H), 1.83 (m, 2H); 13C NMR
δ 170.6, 141.1, 128.4, 128.2, 126.0, 73.8, 38.5, 35.3, 31.5, 21.0,
-0.25; HREIMS [M+] calcd for C13H17IO2, 332.0273; found,
1
332.0242. 5b: yellow oil; H NMR (CDCl3) δ 7.28 (m, 5H), 4.27
(m, 1H), 4.11 (m, 2H), 2.88 (m, 1H), 2. 71 (m, 1H), 2.19-2.02
C
16H16IO2, 240.1150; found, 240.1150.
(m, 4H), 1.99 (s, 3H); 13C NMR δ 170.8, 140.4, 128.4, 128.2, 126.0,
9490 J . Org. Chem., Vol. 67, No. 26, 2002

(m, 2H), 2.05 (s, 3H); 13C NMR δ 170.4, 137.7, 128.4, 127.7, 127.6,
SCHEME 2
73.2, 72.7, 70.1, 35.0, 21.0, 0.037; HREIMS [M+] calcd for C10H17
IO3, 348.0222; found, 348.0221.
-
Acetic Acid 1-(2-Ben zyloxyeth yl)-3-iod o-p r op yl Ester s
(7a a n d 7b). The reaction gave a mixture of 7a and 7b whose
ratio (7a :7b ) 4:1) was determined by 1H NMR spectroscopy,
and the compounds were separated by column chromatography
(2 cm × 25 cm; eluent ) 1:2 Et2O/n-hexan) to give 7a (67%) and
1
7b (16%). 7a : yellow oil; H NMR (CDCl3) δ 7.30 (m, 5H), 5.04
(m, 1H), 4.45 (s, 2H), 3.47 (m, 2H), 3.09 (m, 2H), 2.11 (m, 2H),
2.00 (s, 3H), 1.89 (m, 2H); 13C NMR δ 170.5, 138.1, 128.3, 127.7,
127.6, 73.1, 72.1, 66.3, 38.7, 33.8, 21.0, -0.255; HREIMS [M+]
calcd for C14H19IO3, 362.0378; found, 362.0396. 7b: yellow oil;
1H NMR (CDCl3) δ 7.29 (m, 5H), 4.50 (s, 2H), 4.48-4.16 (m, 3H),
3.62 (m, 2H), 2.12-2.01 (m, 4H), 2.03 (s, 3H); 13C NMR δ 170.8,
138.1, 128.3, 127.7, 127.6, 73.2, 69.4, 64.1, 40.5, 39.2, 29.9, 20.8;
HREIMS [M+] calcd for C14H19IO3, 362.0378; found, 362.0356.
Acetic Acid 1-Ben zyloxym eth yl-2-iod o-eth yl Ester (8a ).
The same procedure described for compound 1a was carried out
to give 8a (91%) as the sole product. Conpound 8b could not be
detected by 1H NMR. 8a : yellow oil; 1H NMR (CDCl3) δ 7.29 (m,
5H), 4. 90 (m, 1H), 4.54 (q, J ) 3.4, 2H), 3.67 (dd, J ) 10.3, 4.9,
1H), 3.56 (dd, J ) 10.3, 5.1, 1H), 3.43 (dd, J ) 10.4, 5.6, 1H),
3.33 (dd, J ) 10.4, 5.6, 1H), 2.07 (s, 3H); 13C NMR δ 170.01,
137.55, 128.41, 127.82, 127.68, 73.39, 71.30, 70.02, 20.96, 3.92;
HREIMS [M+] calcd for C12H15IO3, 334.0065; found, 334.0059.
Acetic Acid 3-Ben zyloxy-1-iod om eth ylp r op yl Ester (9a ).
The same procedure described for compound 1a was carried out
to give 9a (92%) as the sole product. Isomeric 9b could not be
detected by 1H NMR. 9a : yellow oil; 1H NMR (CDCl3) δ 7.31
(m, 5H), 4. 84 (m, 1H), 4.46 (q, J ) 4.3, 2H), 3.48 (m, 2H), 3.44
(dd, J ) 10.6, 4.7, 1H), 3.27 (dd, J ) 10.7, 5.0, 1H), 2.02 (s, 3H),
1.96 (m, 2H); 13C NMR δ 170.15, 137.99, 128.35, 127.64, 127.62,
73.02, 69.87, 65.79, 34.39, 20.98, 8.83; HREIMS [M+] calcd for
F IGURE 1. Proposed mechanism of acylative cleavage of
cyclic ethers with SmI2.
C
13H17IO3, 348.022; found, 348.023.
Acetic Acid 1-Iod om eth yl-3-p h en ylp r op yl Ester (10a ).
The same procedure described for compound 1a was carried out
to give 10a (91%) as the sole product. Isomeric 10b could not be
detected by 1H NMR. 10a : yellow oil; 1H NMR (CDCl3) δ 7.23
(m, 5H), 4. 71 (m, 1H), 3.36 (dd, J ) 10.8, 5.2, 1H), 3.26 (dd, J
) 10.7, 5.2, 1H), 2.63 (m, 2H), 2. 07 (s, 3H), 1.99 (m, 2H); 13C
NMR δ 170.32, 140.73, 128.50, 128.28, 126.16, 71.72, 35.77,
31.39, 21.04, 8.14; HREIMS [M+] calcd for C12H15IO2, 318.0116;
found, 318.0110.
F IGURE 2.
Ack n ow led gm en t. This work was supported by
Grant R03-2001-00033 from the Korea Science & En-
gineering Foundation.
63.9, 42.1, 39.1, 35.4, 32.6, 20.8; HREIMS [M+] calcd for C13H17
IO2, 332.0273; found, 332.0207.
-
Acetic Acid 1-Ben zyloxym eth yl-3-iod o-p r op yl Ester s (6a
a n d 6b). The same procedure described for compound 1a was
carried out to give 6a as the sole product (81%). Compound 6b
could not be detected by 1H NMR. 6a : yellow oil; 1H NMR
(CDCl3) δ 7.32 (m, 5H), 5.05 (m, 1H), 4.53 (d, J ) 11.8, 1H),
4.49 (d, J ) 12.1, 1H), 3.52 (d, J ) 4.6, 2H), 3.11 (m, 2H), 2.20
Su p p or tin g In for m a tion Ava ila ble: Experimental de-
1
tails and spectral data of H NMR, 13C NMR, and HREIMS
for the new compounds. This material is available free of
charge via the Internet at http://pubs.acs.org.
J O020179R
J . Org. Chem, Vol. 67, No. 26, 2002 9491