Three-Component Coupling of Acylphosphonates and Two Carbonyl Compounds Promoted by Low-Valent Samariums: One-Pot Synthesis of β-Hydroxyphosphonates

Article abstract of DOI:10.1021/jo991357s

Three-component coupling of acylphosphonates and two carbonyl compounds leading to β-hydroxyphosphonates has been achieved with low-valent samariums. Thus, acylphosphonates reacted with aldehydes in the presence of semicatalytic amounts of samarium metal or SmI₂ to give acyloxyphosphonates in good yields. The second coupling reaction of the acyloxyphosphonates with aldehydes or ketones promoted by SmI₂ afforded β-hydroxyphosphonates instead of olefins. Moreover, these two reactions could be carried out in one pot.

Full text of DOI:10.1021/jo991357s

J . Org. Chem. 2000, 65, 475-481
475
Th r ee-Com p on en t Cou p lin g of Acylp h osp h on a tes a n d Tw o
Ca r bon yl Com p ou n d s P r om oted by Low -Va len t Sa m a r iu m s:
On e-P ot Syn th esis of â-Hyd r oxyp h osp h on a tes
Ken Takaki,* Yuichiro Itono, Akihiro Nagafuji, Yoji Naito, Tetsuya Shishido,
Katsuomi Takehira, Yoshikazu Makioka,† Yuki Taniguchi,† and Yuzo Fujiwara†
Department of Applied Chemistry, Faculty of Engineering, Hiroshima University,
Kagamiyama, Higashi-Hiroshima 739-8527, J apan, and Department of Chemistry and Biochemistry,
Graduate School of Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, J apan
Received August 25, 1999
Three-component coupling of acylphosphonates and two carbonyl compounds leading to â-hydroxy-
phosphonates has been achieved with low-valent samariums. Thus, acylphosphonates reacted with
aldehydes in the presence of semicatalytic amounts of samarium metal or SmI2 to give acyloxy-
phosphonates in good yields. The second coupling reaction of the acyloxyphosphonates with
aldehydes or ketones promoted by SmI2 afforded â-hydroxyphosphonates instead of olefins.
Moreover, these two reactions could be carried out in one pot.
In tr od u ction
To achieve the deoxygenative coupling of ketones and
aldehydes by low-valent lanthanides, we planned an
indirect method by using acylphosphonates and Sm metal
or SmI2, in which one oxygen would be eliminated as a
carboxylic acid and the other as a phosphate (eq 1). That
Deoxygenative coupling of carbonyl compounds leading
to substituted olefins is an important process in organic
synthesis that can be promoted by various low-valent
metals and metal complexes.1 However, of the metals,
lanthanides have been rarely used for this transformation
despite their strong reducing ability and oxophilicity. The
reaction with SmI2 has been known to produce pinacols,
but further deoxygenation could not be accomplished.2
Reductive homologation of CO mediated by (C5Me5)2Sm-
(thf)2 did not include deoxygenation formally.3 It has been
also reported that treatment of diaryl ketones with
lanthanide metals (Yb, Sm) gave dianion complexes, [Ln-
(OCAr2)(hmpa)2]2, which were reduced further with the
excess metals to afford µ-diarylmethylidene intermedi-
ates instead of the coupling products.4 Only the SmI2-
Sm system succeeded in the transformation of amides
to yield vic-diaminoolefins.5
is, this scenario constitutes three individual steps as
shown in Scheme 1: (i) reaction of acylphosphonates with
aldehydes to yield acyloxyphosphonates, (ii) reductive
elimination of carboxylic acids, followed by coupling with
ketones, and (iii) Horner-Emmons olefination. With
respect to the first step, we have previously reported that
the C-P bond of acylphosphonates was readily cleaved
by Yb and Sm metals to generate lanthanide phospho-
nates.6 Reductive elimination of the carboxylic acid in the
second step would also be facile on the analogy of many
R-oxygenated ketones and esters being reduced with
SmI2.2 Moreover, if each step proceeds successively, the
overall reaction could be carried out in one pot.
With such consideration in mind, we investigated these
reactions and found that the former two reactions worked
well, but the third Horner-Emmons reaction did not.
Consequently, the overall reaction produced â-hydroxy-
phosphonates in good yields, which were, of course,
converted to the expected olefins by treatment with other
bases. We describe herein these results.
* Phone: 81-824-24-7738. Fax: 81-824-22-7191. E-mail: ktakaki@ipc.
hiroshima-u.ac.jp.
† Kyushu University.
(1) (a) Robertson, G. M. In Comprehensive Organic Synthesis; Trost,
B. M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991; Vol. 3, pp 563-
611. (b) McMurry, J . E. Chem. Rev. 1989, 89, 1513-1524. (c) Lenoir,
D. Synthesis 1989, 883-897. (d) Kahn, B. E.; Rieke, R. D. Chem. Rev.
1988, 88, 733-745.
(2) (a) Imamoto, T. Lanthanides in Organic Synyhesis; Academic
Press: London, 1994. (b) Molander, G. A. Chem. Rev. 1992, 92, 29-
68. (c) Molander, G. A. In Comprehensive Organic Synthesis; Trost, B.
M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991; Vol. 1, pp 251-
282.
(3) (a) Evans, W. J .; Grate, J . W.; Hughes, L. A.; Zhang, H.; Atwood,
J . L. J . Am. Chem. Soc. 1985, 107, 3728-3730. (b) Evans, W. J .;
Hughes, L. A.; Drummond, D. K.; Zhang, H.; Atwood, J . L. J . Am.
Chem. Soc. 1986, 108, 1722-1733. (c) Evans, W. J .; Drummond, D. K.
J . Am. Chem. Soc. 1988, 110, 2772-2774. (d) Evans, W. J .; Drummond,
D. K.; Chamberlain, L. R.; Doedens, R. J .; Bott, S. G.; Zhang, H.;
Atwood, J . L. J . Am. Chem. Soc. 1988, 110, 4983-4994.
(4) (a) Hou, Z.; Yamazaki, H.; Kobayashi, K.; Fujiwara, Y.; Tanigu-
chi, H. J . Chem. Soc., Chem. Commun. 1992, 722-724. (b) Hou, Z.;
Yamazaki, H.; Fujiwara, Y.; Taniguchi, H. Organometallics 1992, 11,
2711-2714. (c) Hou, Z.; Wakatsuki, Y. In Lanthanides: Chemistry and
Use in Organic Synthesis; Kobayashi, S., Ed.; Springer: Berlin, 1999;
pp 233-253.
Resu lts a n d Discu ssion
At first, reaction of diethyl p-toluoyl- and benzoylphos-
phonates (1a and 1b) with benzaldehyde was investi-
(5) (a) Ogawa, A.; Takami, N.; Sekiguchi, M.; Ryu, I.; Kambe, N.;
Sonoda, N. J . Am. Chem. Soc. 1992, 114, 8729-8730. (b) Ogawa, A.;
Takami, N.; Nanke, T.; Ohya, S.; Hirao, T.; Sonoda, N. Tetrahedron
1997, 53, 12895-12902.
(6) Taniguchi, Y.; Fujii, N.; Takaki, K.; Fujiwara, Y. J . Organomet.
Chem. 1995, 491, 173-179.
10.1021/jo991357s CCC: $19.00 © 2000 American Chemical Society
Published on Web 12/29/1999

476 J . Org. Chem., Vol. 65, No. 2, 2000
Takaki et al.
Ta ble 2. P r ep a r a tion of Acyloxyp h osp h on a tes 2-14a
Sch em e 1
Ta ble 1. Rea ction of Acylp h osp h on a tes 1 w ith
Ben za ld eh yd ea
decrease of the yield (run 5). In the reaction of ben-
zoylphosphonate 1b, the effect of various promoters (0.2
equiv) was tested. SmI2 was comparable to Sm metal
(runs 6 and 7), whereas Sm(OiPr)3 did not promote the
reaction (run 8). The product 3 was obtained in lower
yields with Na and Li (runs 9 and 10).
Next, acyloxyphosphonates 2-14 were prepared from
various acylphosphonates 1 and aldehydes, and these
results are summarized in Table 2. Aromatic acylphos-
phonates 1a -d reacted with benzaldehyde to give the
products 2-5 in high yields, wherein electron-withdraw-
ing substituents caused better yields than electron-
donating ones (runs 1-4). However, no reaction took
place with aliphatic acylphosphonate 1e (run 5). Aro-
matic, R,â-unsaturated, and aliphatic aldehydes were
readily converted to the corresponding phosphonates
6-14 (runs 6-14). In contrast, the reaction of 1 with
ketones did not afford the acyloxyphosphonates, in which
a different type of reaction seemed to proceed.8
gated (Table 1). Acyloxyphosphonate 2 was formed in
72% yield from 1a by using 4 equiv of the aldehyde and
a stoichiometric amount of Sm metal (run 1).7 Use of an
excess of the aldehyde is crucial in this reaction. Thus,
the yield of 2 decreased to 7% with an equimolar amount
of benzaldehyde (run 2), which should be attributed to
the homocoupling reaction of the acylphosphonate 1a .6
Less loading of Sm metal showed similar results (runs 3
and 4), but substitution of Sm by Yb metal caused a
The coupling reaction described above would be ex-
plained as shown in Scheme 2. Addition of samarium
phosphonate, which is generated by the reduction of 1
with Sm or SmI2,6 to aldehyde affords samarium alkox-
(7) When the solvent, THF-HMPA (4/1), was changed to THF-1,3-
dimethyl-2-imidazolidinone (4/1), THF-1,1,3,3-tetramethylurea (4/1),
or THF only, the yield of 2 decreased to 13%, 27%, or 25% yields,
respectively.

Sm Coupling of Acylphosphonates
J . Org. Chem., Vol. 65, No. 2, 2000 477
Sch em e 2
Moreover, the reaction of 13 afforded 20 and cyclic
product 21 in 42% and 32% yields, respectively (eq 4).
ide.9 Abstraction of the acyl group from 1 by the alkoxide
results in the formation of acyloxyphosphonate and
regeneration of the phosphonate anion. In fact, intermo-
lecular acyl transfer was proved by the competitive
reaction between the two acyphosphonates 1a and 1f (eq
2). When an equimolar mixture of 1a and 1f was treated
On the basis of the above results, reduction of the
acyloxyphosphonates should be carried out in the pres-
ence of the second carbonyl compound as a radical
trapping agent in order to achieve an effective three-
component coupling. Thus, a mixture of 7 and octanal
(1.2 equiv) was treated with SmI2 (2 equiv) to give
â-hydroxyphosphonate 26 in 46% yield with a diastere-
omer ratio of 59:41 (eq 5). Similarly, the phosphonate 25
with excess benzaldehyde (8 equiv) in the presence of Sm
metal (0.4 equiv), all homo and cross-coupling products
2, 3, 15, and 16 were formed in 70% total yield with a
ratio of 29:16:9:46.
Next, reductive elimination of carboxylic acids from the
acyloxyphosphonates was investigated (eq 3). Treatment
was obtained in 77% yield (66:34) by the reaction of 12
with isobutylaldehyde. Stereochemistry of the diastere-
omers was determined as follows (eq 6). While the major
of 7 with SmI2 (2 equiv) gave the reduced phosphonate
18 in 89% yield.10 Acyloxyphosphonate 14 was similarly
changed to 19 in high yield, whereas the reduction of 3
gave benzylphosphonate 17 in lower yield along with
many unidentified products. In all reactions, no deute-
rium was incorporated in products 17-19 on quenching
with D2O, indicating that radicals, generated in situ,
were not reduced further to R-phosphono carbanions.
diastereomers of 25 and 26 were selectively changed to
(E,E)-dienes 33 and 34, respectively, on treatment with
NaH, conversion of the minor isomers was slow and
nonstereoselective, which is probably a result of epimer-
ization before the Horner-Emmons reaction. Therefore,
the major isomers were assigned to threo and the minor
to erythro. Attempts to produce the olefins directly from
the acyloxyphosphonates and carbonyl compounds with-
out NaH by excess use of SmI2 (4 equiv), elevated
temperature (refluxing), and a polar solvent (THF-
HMPA) were unsuccessful. The reason for this failure is
not clear at present.
(8) For example, the reaction of 1a with benzophenone in the
presence of Sm metal (1 equiv) gave diphenylmethyl tolyl ketone and
diphenylhydroxymethyl tolyl ketone in 73% and 20% yields, respec-
tively. 2-Adamantyl phenyl ketone was prepared in 30% yield from
1b and 2-adamantanone. However, the reaction with ketones having
R-hydrogens such as cyclohexanone gave a complex mixture.
(9) Asymmetric hydrophosphonylation of aldehydes and imines
catalyzed by chiral heterobimetallic lanthanides has been reported:
Shibasaki, M.; Groger, H. In Lanthanides: Chemistry and Use in
Organic Synthesis; Kobayashi, S., Ed.; Springer: Berlin, 1999; pp 199-
232 and references therein.
Results on the coupling reaction of various acyloxy-
phosphonates with carbonyl compounds are summarized
in Table 3. Both ketones and aldehydes gave â-hydroxy-
phosphonates 22-31 in fairly good yields, except for
(10) In the reaction with an equimolar amount of SmI2, 18 was
formed in 51% yield, and 7 was recovered in 21% yield.

478 J . Org. Chem., Vol. 65, No. 2, 2000
Takaki et al.
Ta ble 3. P r ep a r a tion of â-Hyd r oxyp h osp h on a tes 22-31
A, eq 7), and the other is a two-step procedure (method
fr om Acyloxyp h osp h on a tes a n d Keton es or Ald eh yd esa
B, eq 8). When a mixture of 1b, the aldehyde, and ketone
(1:2:0.8) was treated with SmI2 (4 equiv of 1b) (method
A), â-hydroxyphosphonate 24 was obtained in 61% yield,
which is slightly lower than the expected yield (67%)
based on the individual steps (Table 2, run 7 and Table
3, run 3). The yield of 24 was increased to 75% by using
the acylphosphonate 1d , wherein (E)-cinnamylphospho-
nate 18 was also formed as a byproduct in 25% yield
based on 1d . Thus, it is clear that acylphosphonates 1b
and 1d react exclusively with cinnamaldehyde in the first
step and their reaction with cyclohexanone is suppressed.
However, in the second step, the resulting acyloxyphos-
phonates 7 and 12 coupled selectively with cyclohexanone
and not with cinnamaldehyde, despite its excess use. The
two-step reaction (method B) gave the â-hydroxyphos-
phonate 24 in 65% yield from 1b and 84% yield from 1d
(eq 8).
The one-pot reaction was carried out with various
ketones and aldehydes by using acylphosphonate 1d , and
these results are given in Table 4. As a whole, the two-
step reaction (method B) was superior to the one-step
reaction (method A), affording â-hydroxyphosphonates in
yields comparable to those obtained by the stepwise
coupling (Tables 2 and 3). In the reaction by method A,
there is a restriction on the combination of the two
carbonyl compounds. When cyclohexanone and isobutyl-
aldehyde were used as coupling partners of aromatic and
R,â-unsaturated aldehydes (runs 1-3, 5, and 7), decrease
of the yields was not so severe compared with the results
by method B, except for run 5. In contrast, the reaction
with octanal gave the â-hydroxyphosphonates 26 and 27
in low yields (runs 4 and 6). For example, the reaction of
1d with cinnamaldehyde and octanal gave 26, acyloxy-
phosphonate 12, and octylphosphonate 19 in 26%, 22%,
and 52% yields, respectively, wherein three possible
â-hydroxyphosphonates other than 26 were not obtained
(run 4). This result suggests that 1d reacts with the two
aldehydes competitively, but the resulting acyloxyphos-
phonate 14 derived from octanal does not couple with
another molecule of octanal or cinnamaldehyde. In the
reaction with octanal and cyclohexanone, the second
coupling did not proceed effectively by either method,
despite facile formation of the acyloxyphosphonate 14
aromatic and R,â-unsaturated aldehydes (runs 6 and 7).
The reaction with these aldehydes produced many byprod-
ucts, including pinacols, because they were reduced with
SmI2 at a rate comparable to that of the acyloxyphos-
phonates. In the reaction of 8 with octanal, a coupling
reaction took place at the R- and γ-positions to the
phosphonate group, giving rise to 27 and 27′ in 42% and
21% yields, respectively (run 8). For the reaction of
acyloxyphosphonates 13 and 14 derived from aliphatic
aldehydes (R2 ) alkyl), the p-ClC6H4 group showed better
results than did Ph as the substituent R1 (runs 12 and
13). However, stereoselectivity was not changed by the
two leaving groups (runs 4 and 11).
Because it has been found that the two reactions
described above can be promoted by low-valent samari-
ums, we investigated the one-pot reaction of the three-
component coupling with SmI2. Initially, acylphosphonate
1b or 1d , cinnamaldehyde, and cyclohexanone were used
as model substrates. The reaction was carried out by two
different methods: one is a one-step procedure (method

Sm Coupling of Acylphosphonates
J . Org. Chem., Vol. 65, No. 2, 2000 479
Ta ble 4. On e-P ot Rea ction of Acyloxyp h osp h on a te 1d
a n d Tw o Ca r bon yl Com p ou n d sa
Gen er a l P r oced u r e for th e Rea ction of Acylp h osp h o-
n a tes 1 w ith Ald eh yd es. Samarium metal (30 mg, 0.2 mmol)
was heated for 10 min in vacuo. After the mixture cooled to
room temperature, THF (1 mL) and HMPA (1 mL) were added
to the metal. Then, diiodomethane (3 µL) was injected into
the mixture to activate the metal. A solution of acylphospho-
nate 1 (1 mmol) and aldehyde (4 mmol) in THF (3 mL) was
added to the mixture. The slurry was stirred for 3 h at room
temperature to give a homogeneous brown solution, which was
quenched with water (2 mL) and then hydrochloric acid (2 M,
5 mL). After addition of an internal standard such as hepta-
decane for GC analysis, the mixture was extracted with ether,
washed with brine, dried over MgSO4, and concentrated in
vacuo. Acyloxyphosphonates 2-14 were isolated by column
chromatography on silica gel with hexanes/EtOAc eluent.
Large-scale reaction, for example, using 30 mmol of 1, could
be performed in a more concentrated solution (0.6 M, THF/
HMPA ) 4/1). The reactions with other promoters were carried
out similarly. In the competitive reaction between 1a and 1f
with benzaldehyde (eq 2), the four products 2, 3, 15, and 16
were isolated as a mixture by column chromatography on silica
1
gel, and their ratio was determined by H NMR and GC.
Gen er a l P r oced u r e for th e Red u ction of Acyloxyp h os-
p h on a tes 3, 7, 13, a n d 14 w ith Sm I2. SmI2 (0.1 M in THF,
10 mL) was added to a solution of the acyloxyphosphonate (0.5
mmol) in THF (3 mL) at room temperature, and stirring was
continued for 1 h. The reaction was quenched with water (5
mL), and tridecane was added to the mixture as an internal
standard. Then, the mixture was extracted with ether, washed
with sodium hydrogensulfite solution and brine, dried over
MgSO4, and concentrated in vacuo. The residue was chromato-
graphed on silica gel with hexanes/EtOAc eluent to give 17
(28% from 3), 18 (69% from 7), or 19 (70% from 14). In the
reaction of 13, 20 and 21 were isolated in 34% and 20% yields,
respectively.
Gen er a l P r oced u r e for th e Rea ction of Acyloxyp h os-
p h on a tes w ith Keton es or Ald eh yd es. SmI2 (0.1 M in THF,
20 mL) was added to a solution of the acyloxyphosphonate (1
mmol) and ketone or aldehyde (1.2 mmol) in THF (2 mL), and
the mixture was stirred for 1 h at room temperature. The
reaction was quenched with water (10 mL) and hydrochloric
acid (2 M, 10 mL). After addition of tridecane as an internal
standard, the mixture was extracted with ether, washed with
sodium hydrogensulfite solution and brine, and dried over
MgSO4. Concentration of the mixture left a yellow residue,
which was chromatographed on silica gel with hexanes/EtOAc
eluent to give â-hydroxyphosphonate. When the reaction
produced two diastereomers, their ratio was determined by
1H and 13C NMR spectra of the crude mixture. Although the
two diastereomers showed a single peak on GC, they were
separable by column chromatography; the major diastereomer
from 1d and octanal (run 8). Thus, â-hydroxyphosphonate
31 was obtained in 30% yield by method A and 39% yield
by method B along with octylphosphonate 19 in 70% and
61% yields, respectively.
In summary, three-component coupling of acylphos-
phonates and two carbonyl compounds was accomplished
with low-valent samariums to give â-hydroxyphospho-
nates, versatile intermediates, in fairly good yields. The
present reaction is unprecedented and would provide a
potentially useful method for the preparation of the
hydroxyphosphonates despite a failure in their direct
transformation to olefins, because the reaction can be
performed in one pot.
1
(threo) was eluted first, except for 23. H NMR spectra of the
major diastereomer exhibited coupling constants (8.6-9.9 Hz)
between CH(OH)-CH(P) larger than those of the minor
diastereomer (1.2-2.6 Hz). In the reaction of 14 with cyclo-
hexanone, the initial product, diethyl 1-(1′-hydroxycyclohexyl)-
octylphosphonate (31), was dehydrated by the column chro-
matography to give diethyl 1-(1′-cyclohexenyl)octylphosphonate
(31′).
Dieth yl 1-(1′-Hyd r oxycycloh exyl)ben zylp h osp h on a te
(22). Colorless solid; Rf ) 0.44 (silica gel, hexane/EtOAc ) 1/1);
IR (Nujol) 3424, 1211, 1030 cm-1; MS m/z 311 (M+ - Me), 285,
272, 257, 230, 173; 1H NMR (CDCl3) δ 0.91 (3H, t, J ) 6.9
Hz), 1.20-1.94 (10H, m), 1.32 (3H, t, J ) 6.9 Hz), 3.32 (1H, d,
J ) 23.8 Hz), 3.37-3.52 (1H, m), 3.75-3.89 (1H, m), 3.99-
4.23 (3H, m), 7.10-7.57 (5H, m); 13C NMR (CDCl3) δ 15.8 (d,
J ) 6.1 Hz), 16.2 (d, J ) 6.2 Hz), 21.8, 22.1, 25.4, 35.9 (d, J )
10.9 Hz), 38.8 (d, J ) 3.6 Hz), 53.7 (d, J ) 131.9 Hz), 61.1 (d,
J ) 8.6 Hz), 63.2 (d, J ) 7.4 Hz), 72.9 (d, J ) 3.6 Hz), 127.1
(d, J ) 2.4 Hz), 128.1 (two carbons), 134.2 (d, J ) 4.9 Hz).
Anal. Calcd for C17H27O4P: C, 62.56; H, 8.34. Found: C, 62.26;
H, 8.33.
Exp er im en ta l Section
Gen er a l. 1H and 13C NMR spectra were recorded at 400
and 99 MHz, respectively. IR spectra were taken on a FT-IR
spectrophotometer. Mass spectra were obtained at 70 eV on a
GC-MS apparatus. Microanalyses were performed at our
analytical laboratory. All reactions were carried out under
argon. THF was distilled from sodium/benzophenone ketyl
immediately prior to use. HMPA was distilled from CaH2 and
stored over molecular sieves. Samarium and ytterbium metals
(40 mesh) were washed with anhydrous hexane under argon
and dried in vacuo. SmI2 (0.1 M in THF) was prepared by the
reported method.11 Acylphosphonates 1 were prepared con-
ventionally from the corresponding acid chlorides and triethyl
phosphite.12 All other materials were commercially available
and were used after distillation.
(11) Girard, P.; Namy, J . L.; Kagan, H. B. J . Am. Chem. Soc. 1980,
102, 2693-2698.
(12) Kabachnik, M. I.; Rossiiskaya, P. A. Bull. Acad. Sci. URSS,
Cl. Sci. Chim. 1945, 367-374; Chem. Abstr. 1946, 40, 4688.

480 J . Org. Chem., Vol. 65, No. 2, 2000
Takaki et al.
Dieth yl 2-Hyd r oxy-3-m eth yl-1-p h en ylbu tylp h osp h o-
n a te (23) [142465-88-1]. (threo-Isomer, major): colorless solid;
Rf ) 0.24 (silica gel, hexane/EtOAc ) 1/1); IR (Nujol) 3328,
1224, 1029 cm-1; MS m/z 230, 202, 92; 1H NMR (CDCl3) δ 0.79
(3H, d, J ) 6.6 Hz), 0.96 (3H, d, J ) 6.9 Hz), 1.16 (3H, t, J )
7.1 Hz), 1.27 (3H, t, J ) 6.9 Hz), 1.46-1.51 (1H, m), 3.23 (1H,
dd, J ) 20.8 and 9.9 Hz), 3.81-4.23 (6H, m), 7.23-7.34 (5H,
m); 13C NMR (CDCl3) δ 13.6, 16.2 (d, J ) 6.2 Hz), 16.3 (d, J )
6.1 Hz), 20.1, 29.6 (d, J ) 13.4 Hz), 49.5 (d, J ) 134.2 Hz),
62.2 (d, J ) 7.4 Hz), 62.8 (d, J ) 6.1 Hz), 74.9 (d, J ) 4.8 Hz),
127.2 (d, J ) 2.5 Hz), 128.4 (d, J ) 2.5 Hz), 129.5 (d, J ) 6.1
Hz), 134.6 (d, J ) 7.3 Hz). Anal. Calcd for C15H25O4P: C, 60.00;
H, 8.40. Found: C, 59.78; H, 8.46. (erythro-Isomer, minor):
yellow oil; Rf ) 0.27 (silica gel, hexane/EtOAc ) 1/1); IR (neat)
3406, 1231, 1028 cm-1; MS m/z 230, 202, 91; 1H NMR (CDCl3)
δ 0.84 (3H, d, J ) 6.9 Hz), 0.97 (3H, t, J ) 6.9 Hz), 0.99 (3H,
d, J ) 6.6 Hz), 1.35 (3H, t, J ) 7.1 Hz), 1.44-1.57 (1H, m),
3.30 (1H, dd, J ) 25.4 and 2.6 Hz), 3.52 (1H, ddd, J ) 14.9,
7.3, and 2.6 Hz), 3.78-3.93 (3H, m), 4.06-4.23 (2H, m), 7.28-
7.36 (3H, m), 7.49-7.53 (2H, m); 13C NMR (CDCl3) δ 16.0 (d,
J ) 6.1 Hz), 16.3 (d, J ) 6.1 Hz), 18.9, 31.0 (d, J ) 2.5 Hz),
47.2 (d, J ) 135.5 Hz), 61.8 (d, J ) 7.3 Hz), 63.4 (d, J ) 7.3
Hz), 75.9 (d, J ) 3.7 Hz), 127.3 (d, J ) 3.7 Hz), 128.4 (d, J )
2.5 Hz), 130.7 (d, J ) 7.4 Hz), 132.8 (d, J ) 4.9 Hz).
Dieth yl 1-(1′-Hydr oxycycloh exyl)cin n am ylph osph on ate
(24). Yellow oil; Rf ) 0.41 (silica gel, hexane/EtOAc ) 1/1); IR
(neat) 3394, 1601, 1226, 1025 cm-1; MS m/z 335 (M+ - OH),
253 (M+ - C6H10OH), 198 (335 - OP(OEt)2+); 1H NMR (CDCl3)
δ 1.09-1.84 (11H, m), 1.27 (3H, t, J ) 6.9 Hz), 1.34 (3H, t, J
) 6.9 Hz), 2.87 (1H, dd, J ) 21.1 and 10.6 Hz), 4.04-4.21 (4H,
m), 6.21 (1H, ddd, J ) 15.8, 10.6, and 5.6 Hz), 6.48 (1H, dd, J
) 15.8 and 4.8 Hz), 7.22-7.46 (5H, m); 13C NMR (CDCl3) δ
16.3 (d, J ) 2.4 Hz), 16.4 (d, J ) 3.7 Hz), 21.6, 21.8, 25.4, 35.2
(d, J ) 8.5 Hz), 37.6 (d, J ) 5.6 Hz), 53.7 (d, J ) 131.8 Hz),
61.9 (d, J ) 7.3 Hz), 62.5 (d, J ) 6.1 Hz), 72.4 (d, J ) 4.9 Hz),
122.3 (d, J ) 10.9 Hz), 126.3, 127.7, 128.6, 135.1 (d, J ) 13.4
Hz), 136.8. Anal. Calcd for C19H29O4P: C, 64.76; H, 8.29.
Found: C, 64.70; H, 8.25.
J ) 7.3 Hz), 70.2 (d, J ) 4.9 Hz), 121.8 (d, J ) 11.0 Hz), 126.3,
127.8, 128.6, 134.6 (d, J ) 13.4 Hz), 136.7. Anal. Calcd for
C21H35O4P: C, 65.95; H, 9.22. Found: C, 65.92; H, 9.22.
(erythro-Isomer, minor): yellow oil; Rf ) 0.37 (silica gel,
hexane/EtOAc ) 1/1); IR (neat) 3418, 1598, 1229, 1028 cm-1
;
MS m/z 365 (M+ - OH), 250, 228 (365 - OP(OEt)2+), 129
(C8H16OH+); 1H NMR (CDCl3) δ 0.86 (3H, t, J ) 6.9 Hz), 1.20-
1.60 (18H, m), 1.74 (1H, br), 2.81 (1H, ddd, J ) 13.0, 10.0,
and 1.5 Hz), 4.03-4.22 (5H, m), 6.35 (1H, ddd, J ) 16.0, 10.0,
and 6.2 Hz), 6.55 (1H, dd, J ) 16.0 and 5.2 Hz), 7.23-7.42
(5H, m); 13C NMR (CDCl3) δ 14.1, 16.5 (d, J ) 5.7 Hz), 22.6,
25.7, 29.2, 29.4, 31.8, 34.9 (d, J ) 13.9 Hz), 47.9 (d, J ) 136.2
Hz), 62.0 (d, J ) 7.4 Hz), 63.2 (d, J ) 7.4 Hz), 69.9 (d, J ) 5.7
Hz), 119.7 (d, J ) 9.0 Hz), 126.3, 127.8, 128.6, 136.0 (d, J )
14.8 Hz), 136.7.
Dieth yl 5-Hydr oxy-2(E)-dodecen -4-ylph osph on ate (27).
(threo-Isomer, major): colorless oil; Rf ) 0.55 (silica gel,
hexane/EtOAc ) 1/1); IR (neat) 3404, 1229, 1028 cm-1 1H
;
NMR (CDCl3) δ 0.88 (3H, t, J ) 6.9 Hz), 1.20-1.70 (18H, m),
1.73 (3H, t, J ) 5.9 Hz), 2.58 (1H, dt, J ) 18.6 and 9.3 Hz),
3.91-3.96 (2H, m), 4.06-4.23 (4H, m), 5.19-5.31 (1H, m), 5.61
(1H, ddd, J ) 15.3, 6.9, and 4.9 Hz); 13C NMR (CDCl3) δ 14.0,
16.3 (d, J ) 6.1 Hz), 16.4 (d, J ) 6.1 Hz), 18.1 (d, J ) 2.4 Hz),
22.6, 24.9, 29.3, 29.5, 31.8, 35.1 (d, J ) 12.4 Hz), 49.1 (d, J )
134.3 Hz), 62.1 (d, J ) 6.1 Hz), 62.4 (d, J ) 7.3 Hz), 70.0 (d, J
) 4.8 Hz), 122.8 (d, J ) 11.0 Hz), 130.9 (d, J ) 13.4 Hz); HRMS
calcd for C16H32O3P (M+ - OH) 303.2087, found 303.2114.
Anal. Calcd for C16H33O4P: C, 59.98; H, 10.38. Found: C,
59.95; H, 10.48. (erythro-Isomer, minor): colorless oil; Rf ) 0.52
(silica gel, hexane/EtOAc ) 1/1); IR (neat) 3394, 1232, 1029
1
cm-1; H NMR (CDCl3) δ 0.88 (3H, t, J ) 6.9 Hz), 1.19-1.57
(18H, m), 1.75 (3H, t, J ) 5.1 Hz), 2.57 (1H, ddd, J ) 22.4,
9.2, and 1.8 Hz), 3.34 (1H, br s). 4.00-4.19 (5H, m), 5.49-
5.73 (2H, m); 13C NMR (CDCl3) δ 14.1, 16.4 (d, J ) 6.1 Hz),
18.2, 22.6, 25.7, 29.2, 29.4, 31.8, 34.6 (d, J ) 13.4 Hz), 47.2 (d,
J ) 136.7 Hz), 61.8 (d, J ) 7.3 Hz), 62.8 (d, J ) 7.3 Hz), 69.8
(d, J ) 4.9 Hz), 120.6 (d, J ) 8.5 Hz), 132.2 (d, J ) 4.7 Hz).
Dieth yl 4-Hyd r oxy-3-m eth yl-1(E)-u n d ecen ylp h osp h o-
n a te (27′). Obtained as a mixture of two diastereomers (68/
32): colorless oil; Rf ) 0.33 (silica gel, hexane/EtOAc ) 1/1);
1H NMR (CDCl3) δ (major isomer) 0.88 (3H, t, J ) 6.6 Hz),
1.09 (3H, d, J ) 6.6 Hz), 1.20-1.60 (18H, m), 1.70 (1H, br),
2.34-2.46 (1H, m), 3.48-3.62 (1H, m), 4.03-4.20 (4H, m), 5.70
(1H, dd, J ) 20.9 and 17.4 Hz), 6.78 (1H, ddd, J ) 22.3, 17.4,
and 7.6 Hz), (minor isomer) 1.08 (d, J ) 6.6 Hz); 13C NMR
(CDCl3) δ (major isomer) 14.0, 15.5, 16.3 (d, J ) 6.1 Hz), 22.6,
25.7, 29.2, 29.5, 31.8, 34.5, 44.4 (d, J ) 10.7 Hz), 61.7 (d, J )
6.1 Hz), 74.6, 117.8 (d, J ) 186.8 Hz), 154.9 (d, J ) 4.9 Hz),
(minor isomer) 13.5, 14.2, 16.3 (d, J ) 6.1 Hz), 23.3, 24.7, 26.0,
29.7, 34.4, 36.6, 44.1 (d, J ) 8.3 Hz), 61.7 (d, J ) 6.1 Hz), 74.2,
117.1 (d, J ) 186.8 Hz), 155.7 (d, J ) 4.9 Hz).
Diet h yl 4-H yd r oxy-5-m et h yl-1-p h en yl-1(E)-h exen -3-
ylp h osp h on a te (25) [160723-17-1]. (threo-Isomer, major):
yellow oil; Rf ) 0.21 (silica gel, hexane/EtOAc ) 1/1); IR (neat)
1
3328, 1599, 1230, 1029 cm-1; MS m/z 255, 227, 198, 116; H
NMR (CDCl3) δ 0.88 (3H, d, J ) 6.6 Hz), 1.04 (3H, d, J ) 6.9
Hz), 1.33 (6H, t, J ) 7.0 Hz), 1.75-1.87 (1H, m), 2.88 (1H, dt,
J ) 19.1 and 9.9 Hz), 3.88 (1H, ddd, J ) 12.5, 9.9, and 3.0
Hz), 4.07-4.23 (5H, m), 5.97 (1H, ddd, J ) 15.8, 9.9, and 5.6
Hz), 6.51 (1H, dd, J ) 15.8 and 5.0 Hz), 7.22-7.48 (5H, m);
13C NMR (CDCl3) δ 13.6, 16.4 (d, J ) 6.1 Hz), 16.5 (d, J ) 6.1
Hz), 20.1, 30.6 (d, J ) 3.4 Hz), 47.6 (d, J ) 134.3 Hz), 62.4 (d,
J ) 6.1 Hz), 62.8 (d, J ) 7.3 Hz), 73.7 (d, J ) 6.1 Hz), 121.7
(d, J ) 12.2 Hz), 126.3, 127.8, 128.6, 133.9 (d, J ) 13.4 Hz),
136.7. Anal. Calcd for C17H27O4P: C, 62.56; H, 8.34. Found:
C, 62.39; H, 8.07. (erythro-Isomer, minor): yellow oil; Rf ) 0.16
(silica gel, hexane/EtOAc ) 1/1); IR (neat) 3382, 1230, 1026
cm-1; 1H NMR (CDCl3) δ 0.84 (3H, d, J ) 6.6 Hz), 1.04 (3H, d,
J ) 6.6 Hz), 1.25 (3H, t, J ) 7.0 Hz), 1.36 (3H, t, J ) 7.1 Hz),
1.59-1.80 (2H, m), 2.98 (1H, ddd, J ) 24.2, 10.1 and 1.2 Hz),
3.72 (1H, dt, J ) 1.2 and 8.6 Hz), 4.01-4.24 (4H, m), 6.38 (1H,
ddd, J ) 16.0, 10.1, and 5.8 Hz), 6.57 (1H, dd, J ) 16.0 and
5.1 Hz), 7.21-7.58 (5H, m); 13C NMR (CDCl3) δ 16.4 (d, J )
6.1 Hz), 18.5, 19.4, 31.6 (d, J ) 11.6 Hz), 45.8 (d, J ) 136.8
Hz), 62.1 (d, J ) 7.3 Hz), 63.4 (d, J ) 7.4 Hz), 75.2 (d, J ) 6.1
Hz), 119.6 (d, J ) 8.6 Hz), 126.3, 127.7, 128.6, 135.5 (d, J )
13.4 Hz), 136.8.
Dieth yl 3,7-Dim eth yl-1-(1′-h yd r oxycycloh exyl)-2,6-oc-
ta d ien ylp h osp h on a te (28). Obtained as a mixture of (E) and
(Z)-isomer (61:39): yellow oil; Rf ) 0.51 (silica gel, hexane/
EtOAc ) 1/1); IR (neat) 3423, 1262, 1028 cm-1; MS m/z 357
(M+ - Me), 275, 206, 151; 1H NMR (CDCl3) δ 1.29 (3H, t, J )
6.8 Hz), 1.32 (3H, t, J ) 6.8 Hz), 1.37-1.81 (20H, m), 2.00-
2.20 (4H, m), 2.93 (0.6H, dd, J ) 21.3 and 11.1 Hz, major),
2.96 (0.4H, dd, J ) 21.4 and 11.2 Hz, minor), 4.00-4.35 (4H,
m), 5.02-5.16 (1H, m), 5.16-5.28 (1H, m); 13C NMR (CDCl3)
(clearly assignable peaks) δ 48.1 (d, J ) 131.8 Hz, minor) and
48.4 (d, J ) 131.8 Hz, major), 72.5 (d, J ) 4.9 Hz, minor) and
72.7 (d, J ) 4.9 Hz, major), 116.87 (d, J ) 9.7 Hz, major) and
116.93 (d, J ) 9.7 Hz, minor), 123.9 (major and minor), 131.6
(major) and 131.8 (minor), 140.4 (d, J ) 13.5 Hz, major) and
140.5 (d, J ) 13.4 Hz, minor). Anal. Calcd for C20H37O4P: C,
64.49; H, 10.01. Found: C, 64.73; H, 9.89.
Dieth yl 2,6-Dim eth yl-9-h yd r oxy-2,6-h exa d eca d ien -8-
ylp h osp h on a te (29). (threo-Isomer): obtained as a mixture
of (E) and (Z)-isomer (78:22); yellow oil; Rf ) 0.40 (silica gel,
hexane/EtOAc ) 1/1); IR (neat) 3384, 1229, 1029 cm-1; MS
m/z 402 (M+), 273 (M+ - C8H16OH), 232, 206; 1H NMR (CDCl3)
(major isomer) δ 0.87 (3H, t, J ) 6.9 Hz), 1.26-1.78 (28H, m),
2.06-2.14 (4H, m), 2.86 (1H, dt, J ) 19.0 and 9.6 Hz), 3.78-
3.93 (1H, m), 4.08-4.19 (4H, m), 4.96 (1H, dd, J ) 10.4 and
Diet h yl 4-H yd r oxy-1-p h en yl-1(E)-u n d ecen -3-ylp h os-
p h on a te (26). (threo-Isomer, major): yellow oil; Rf ) 0.43
(silica gel, hexane/EtOAc ) 1/1); IR (neat) 3402, 1601, 1225,
1027 cm-1; MS m/z 365 (M+ - OH), 228 (365 - OP(OEt)2+),
1
129 (C8H16OH+); H NMR (CDCl3) δ 0.85 (3H, t, J ) 6.8 Hz),
1.24-1.67 (19H, m), 2.81 (1H, ddd, J ) 18.8, 10.2, and 8.6 Hz),
3.96-4.05 (1H, m), 4.07-4.22 (4H, m), 6.00 (1H, ddd, J ) 15.8,
10.2, and 5.9 Hz), 6.51 (1H, dd, J ) 15.8 and 4.9 Hz), 7.22-
7.60 (5H, m); 13C NMR (CDCl3) δ 14.1, 16.4 (d, J ) 4.9 Hz),
16.5 (d, J ) 6.1 Hz), 22.6, 25.0, 29.3, 29.5, 31.8, 35.5 (d, J )
12.2 Hz), 49.7 (d, J ) 134.3 Hz), 62.4 (d, J ) 7.3 Hz), 62.7 (d,

Sm Coupling of Acylphosphonates
J . Org. Chem., Vol. 65, No. 2, 2000 481
4.8 Hz), 5.02-5.12 (1H, m); 13C NMR (CDCl3) (clearly assign-
able peaks) δ 42.7 (d, J ) 135.4 Hz, minor) and 44.6 (d, J )
134.3 Hz, major), 70.5 (d, J ) 4.9 Hz, major) and 70.8 (d, J )
3.6 Hz, minor), 116.5 (d, J ) 11.0 Hz, major) and 116.8 (d, J
) 9.8 Hz, minor), 123.8 (major and minor), 131.7 (major) and
132.0 (minor), 140.0 (d, J ) 13.4 Hz, major) and 141.5 (d, J )
13.4 Hz, minor). Anal. Calcd for C22H43O4P: C, 65.64; H, 10.77.
Found: C, 65.63; H, 10.75. (erythro-Isomer): obtained as a
mixture of (E) and (Z)-isomer (74:26); yellow oil; Rf ) 0.39
(silica gel, hexane/EtOAc ) 1/1); 1H NMR (CDCl3) (major
isomer) δ 0.87 (3H, t, J ) 6.9 Hz), 1.26-1.81 (28H, m), 2.05-
2.15 (4H, m), 2.83 (1H, ddd, J ) 23.1, 10.7 and 2.1 Hz), 3.99-
4.17 (5H, m), 5.03-5.15 (1H, m), 5.35 (1H, dd, J ) 10.4 and
4.6 Hz); 13C NMR (CDCl3) (clearly assignable peaks) δ 42.7
(d, J ) 129.3 Hz, minor) and 42.8 (d, J ) 136.7 Hz, major),
70.0 (d, J ) 4.9 Hz, major) and 70.5 (d, J ) 4.9 Hz, minor),
113.9 (d, J ) 8.5 Hz, major) and 114.2 (d, J ) 8.6 Hz, minor),
123.8 (major and minor), 131.7 (major) and 131.9 (minor),
141.5 (d, J ) 13.4 Hz, major) and 141.8 (d, J ) 13.4 Hz, minor).
Dieth yl 3,7-Dim eth yl-1-(1′-h yd r oxycycloh exyl)-6-octe-
n ylp h osp h on a te (30). Obtained as a mixture of two diaste-
reoisomers (56:44): colorless oil; Rf ) 0.40 (silica gel, hexane/
(CDCl3) δ 16.3, (d, J ) 6.1 Hz), 18.2, 21.6, 21.8, 25.4, 34.8 (d,
J ) 7.3 Hz), 37.3 (d, J ) 9.8 Hz), 53.3 (d, J ) 130.6 Hz), 61.8
(d, J ) 7.3 Hz), 62.3 (d, J ) 7.3 Hz), 72.0 (d, J ) 3.7 Hz), 123.2
(d, J ) 9.8 Hz) 131.3 (d, J ) 7.3 Hz). Anal. Calcd for
C
14H27O4P: C, 57.92; H, 9.37. Found: C, 58.23; H, 9.28.
Con ver sion of â-Hyd r oxyp h osp h on a tes 25 a n d 26 to
Olefin s 33 a n d 34. Pure threo- or erythro-â-hydroxyphospho-
nate (0.5 mmol) in THF (5 mL) was added to a suspension of
NaH (15 mg, 0.6 mmol) in THF (5 mL) at room temperature
or -15 °C, and the mixture was stirred for an appropriate time
(eq 6) with monitoring by GC. After usual workup, the residue
was chromatographed on silica gel with hexane eluent to give
33 (64% from threo-25 and 68% from erythro-25) or 34 (75%
from threo-26 and 68% from erythro-26) as a mixture of (E,E)
and (E,Z)-isomers. The ratio of the two isomers was deter-
mined by GC of the crude reaction mixture.
Gen er a l P r oced u r e for t h e On e-P ot Cou p lin g of
Acylp h osp h on a tes 1 w ith Tw o Ca r bon yl Com p ou n d s.
Method A (one-step reaction): SmI2 (0.1 M in THF, 20 mL)
was slowly added to a solution of acylphosphonate 1 (0.5
mmol), aldehyde (1 mmol), and the second aldehyde or ketone
(0.4 mmol) in THF (3 mL)-HMPA (1 mL) over 1 h at 0 °C
and stirring was continued for additional 1 h at 0 °C. The
reaction was quenched with hydrochloric acid (2 M, 10 mL),
and an internal standard such as tridecane was added to the
mixture. Then, the reaction mixture was extracted with ether,
washed with sodium hydrogensulfite solution and brine, dried
over MgSO4, and concentrated in vacuo. The products were
isolated by column chromatography on silica gel with hexanes/
EtOAc eluent. Method B (two-step reaction): SmI2 (0.1 M in
THF, 5 mL) was slowly added to a solution of acylphosphonate
1 (0.5 mmol) and aldehyde (1 mmol) in THF (3 mL)-HMPA
(1 mL) over 15 min at 0 °C, and the mixture was stirred for
additional 45 min at 0 °C. After addition of the second aldehyde
or ketone (0.4 mmol), SmI2 (15 mL, 1.5 mmol) was added over
15 min to the mixture at 0 °C, and then stirring was continued
for 45 min at room temperature. The mixture was worked up
similarly as above.
EtOAc ) 1/1); IR (neat) 3398, 1234, 1026 cm-1 1H NMR
;
(CDCl3) (major isomer) δ 0.83 (3H, d, J ) 6.3 Hz), 0.94-2.06
(18H, m), 1.26 (6H, t, J ) 6.3 Hz), 1.54 (3H, s), 1.61 (3H, s),
3.92-4.15 (4H, m), 4.37 (1H, br s), 4.96-5.07 (1H, m), (minor
isomer) 0.80 (d, J ) 6.6 Hz), 1.25 (t, J ) 6.3 Hz), 4.45 (br s);
13C NMR (CDCl3) (clearly assignable peaks) δ 16.4 (d, J ) 6.1
Hz, major and minor), 46.3 (d, J ) 130.6 Hz, major) and 46.5
(d, J ) 130.7 Hz, minor), 61.36, 61.45, and 61.6 (three d, J )
7.3 Hz, major and minor), 72.6 (d, J ) 4.8 Hz, minor) and 72.8
(d, J ) 3.7 Hz, major), 124.6 (major) and 124.7 (minor), 131.2
(minor) and 131.3 (major). Anal. Calcd for C20H39O4P: C, 64.14;
H, 10.50. Found: C, 64.31; H, 10.45.
Dieth yl 1-(1′-Cycloh exen yl)octylph osph on ate (31′). Col-
orless oil; IR (neat) 1653, 1248, 1028 cm-1; MS m/z 330 (M+),
246, 233, 135, 94; 1H NMR (CDCl3) δ 0.88 (3H, t, J ) 6.6 Hz),
1.14-1.40 (16H, m), 1.53-1.79 (6H, m), 1.95-2.18 (4H, m),
2.36 (1H, ddd, J ) 22.8, 9.6, and 5.6 Hz), 4.00-4.18 (4H, m),
5.59-5.68 (1H, m); 13C NMR (CDCl3) δ 14.1, 16.4 (d, J ) 6.1
Hz), 16.5 (d, J ) 4.9 Hz), 22.3, 22.6, 23.0, 25.5, 27.0, 27.1, 27.4
(d, J ) 4.9 Hz), 27.6, 29.1 (d, J ) 9.8 Hz), 31.8, 45.9 (d, J )
135.5 Hz), 61.4 (d, J ) 7.3 Hz), 62.1 (d, J ) 7.3 Hz), 126.5 (d,
J ) 12.2 Hz) 132.2 (d, J ) 8.5 Hz). Anal. Calcd for C18H35O3P:
C, 65.43; H, 10.68. Found: C, 65.71; H, 10.53.
Ack n ow led gm en t. This work was financially sup-
ported by a Grant-in-Aid for Scientific Research from
the Ministry of Education, Science, and Culture of
J apan.
Diet h yl 1-(1′-H yd r oxycycloh exyl)-2(E)-b u t en ylp h os-
p h on a te (32). Colorless oil; Rf ) 0.31 (silica gel, hexane/EtOAc
) 1/1); IR (neat) 3425, 1223, 1024 cm-1; MS m/z 193, 165, 137
(OP(OEt)2+); 1H NMR (CDCl3) δ 1.12-1.78 (14H, m), 1.30 (3H,
t, J ) 6.9 Hz), 1.32 (3H, t, J ) 6.9 Hz), 2.62 (1H, dd, J ) 20.6
and 10.1 Hz), 4.05-4.16 (4H, m), 5.35-5.65 (2H, m); 13C NMR
Su p p or tin g In for m a tion Ava ila ble: Characterization
data (IR, MS, 1H and 13C NMR spectra and elemental analyses)
of compounds 2-14, 17-21, 33, and 34. This material is
available free of charge via the Internet at http://pubs.asc.org.
J O991357S