New entry to the Pauson-Khand reaction: Trimethylgermyl group at the triple bond terminus as a latent functional group

Article abstract of DOI:10.1016/j.tet.2004.01.041

The Pauson-Khand reaction of enynes possessing a trimethylgermyl group at the alkyne terminus afforded the corresponding bicyclo[3.3.0]octenone and bicyclo[4.3.0]nonenone skeletons in a stereoselective manner. The resulting trimethylgermyl group of the bicyclic compounds was then converted to the iodo group, which was used for further elaboration. Thus, the trimethylgermyl group at the triple bond terminus was shown to be a precursor for other appendages.

Full text of DOI:10.1016/j.tet.2004.01.041

Tetrahedron 60 (2004) 2497–2507
New entry to the Pauson–Khand reaction: trimethylgermyl group
at the triple bond terminus as a latent functional group
*
Chisato Mukai, Takashi Kozaka, Yukihiro Suzuki and In Jong Kim
Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi 13-1, Kanazawa 920-0934 Japan
Received 20 December 2003; revised 16 January 2004; accepted 16 January 2004
Abstract—The Pauson–Khand reaction of enynes possessing a trimethylgermyl group at the alkyne terminus afforded the corresponding
bicyclo[3.3.0]octenone and bicyclo[4.3.0]nonenone skeletons in a stereoselective manner. The resulting trimethylgermyl group of the
bicyclic compounds was then converted to the iodo group, which was used for further elaboration. Thus, the trimethylgermyl group at the
triple bond terminus was shown to be a precursor for other appendages.
q 2004 Elsevier Ltd. All rights reserved.
1. Introduction
the total synthesis of bioactive compounds, the bicyclo-
[
3.3.0]octenone derivatives 2 (n¼1) with a suitable carbon
1
The Co (CO) -mediated Pauson–Khand reaction (PKR) is
2
appendage at the C -position were required as a core carbon
2
6
recognized as one of the most convenient and straight-
forward methods for the construction of bicyclo[3.3.0] as
well as bicyclo[4.3.0] ring systems. Recent efforts from this
framework. However, the PKR of the corresponding 1
(n¼1) gave only a mixture of 2 (n¼1) and its C -epimer in a
5
moderately stereoselective manner, or nonstereoelectively
5
(Scheme 1).
2
,3
laboratory have led to the development of the highly
stereoselective Pauson–Khand reaction of the enynes ent-1
leading to the formation of the bicyclo[3.3.0]octenone and
Thus, the stereoselectivity recorded in the PKR of 1
appeared to depend in part on the bulkiness of the
substituent at the triple bond terminus. In order to improve
the low stereoselectivity encountered in the formation of
2
,3
the bicyclo[4.3.0]nonenone derivatives ent-2 possessing
two distinguishable hydroxyl groups. In particular, the
exclusive formation of ent-2a (n¼1,2) was observed when
1
2
2,3
5
both substituents (R and R ) were sterically bulky silyl
2b (n¼1,2)
and 2 with a carbon side chain at the
C -position, we concentrated on the silyl group at the triple
1
2
groups (R ¼TBDMS and R ¼TMS). However, upon
2
exposure of the enyne 1b (n¼1) to PKR conditions, the
bond terminus, since a bulky silyl group at the triple bond
terminus might not only govern the diastereoselectivity in
2
ring-closed product 2b (n¼1) was obtained nonselectively.
3
6
Similarly, a decrease in stereoselectivity was observed in
the formation of the homologated 2b (n¼2). In addition,
the PKR, but could also be replaced under electrophilic
substitution. Therefore, the terminal silyl moiety can be
considered as a latent functional group. As a result,
4
during the course of our program directed toward the
application of the newly developed stereoselective PKR to
2
compound 2a (n¼1), obtained from 1a in a stereo-
controlled manner, would become a versatile intermediate
for the stereoselective preparation of several bicyclo[3.3.0]
and bicyclo[4.3.0] skeletons 2 possessing a useful sub-
stituent at the a-position of the carbonyl functionality if
efficient transformation of the vinylic TMS group into the
suitable carbon tethers and hydrogen atom could be
realized. However, treatment of 2a (n¼1) under typical
7
8
conditions using I or NIS, showed no reaction at all and
2
the starting 2a (n¼1) was completely recovered intact.
9
Negishi’s procedure with ICl or the ICl–AlCl system also
3
was found not to be effective in this case. Consequently, we
examined the PKR of 1 having a stannyl or germyl group
instead of a silyl group at the triple bond terminus and the
further transformation of the resulting 2 into the corre-
sponding target compounds. In this paper, we describe in
detail the results of (i) the highly stereoselective PKR of
Scheme 1.
Keywords: Pauson–Khand reaction; Enyne; Trimethylgermyl group;
Latent functional group; NIS.
1
0
*
Corresponding author. Tel.: þ81-76-234-4411; fax: þ81-76-234-4410;
e-mail address: cmukai@kenroku.kanazawa-u.ac.jp
0040–4020/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2004.01.041

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C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
Table 1.
Entry
R
Condition
Yield (%)
4
5
6
1
2
3
4
5
6
Bu
Bu
Me
Me
Ph
A
B
A
B
A
B
47
65
26
24
27
48
14
—
21
24
17
Trace
—
—
8
9
—
—
Ph
˚
3 3
Condition A: heated in CH CN at 50–55 8C. Condition B: heated in CH CN at 50–55 8C in the presence of 4 A MS.
enynes having a trimethylgermyl group at the triple bond
terminus and (ii) the successful transformation of the
trimethylgermyl group into the desired functionalities.
tin atom to the trimethyl and triphenyl groups did not
improve the chemical yield of 4 (entries 3–6). In the PKR of
the trimethylstannylated derivative (entries 3 and 4), a small
amount of the dimer 6 was observed. These results are
summarized in Table 1. In contrast to compound 2a with the
TMS group, conversion of 4a with the tributylstannyl group
into the corresponding iodo derivative 7 (97%) was easily
We started out this study by investigating the PKR of the
2
stannyl compounds, derived from compound 3. Treatment
of the acetylide of 3 with tributyltin chloride afforded the
corresponding enyne with the tributylstannyl functionality
at the triple bond terminus. Because of its instability, the
stannylated enyne was directly converted to the cobalt
complex, which was then heated at 50–55 8C in aceto-
7
realized by simple treatment with I2 in THF at rt.
Although the transformation of 3 into the iodide 7, a key
compound for various transformations, proceeded in a com-
pletely stereocontrolled manner via the corresponding
stannylated 3 (Table 1, entry 2), this procedure (exclusive
formation of 4a without detection of 5 and 6) could not be
reproduced easily due to facile destannylation under PKR
conditions. Therefore, a more reliable and reproducible
method was required. To this end, we introduced a tri-
methylgermyl group instead of the tributylstannyl group at
the alkyne terminus of 3 with the expectation that (i) the
germyl group would be more reactive toward electrophilic
1
1
nitrile to provide 4a in 47% yield in a stereoselective
manner along with the nonstereoselective formation of 5
2
b
(
50:50). The bicyclic compound 4a was stable enough
under PKR conditions, so that the formation of 5 could be
rationalized by destannylation before the ring-closing
reaction occurred. When the ring-closing reaction was
˚
carried out in the presence of 4 A molecular sieves, 4a was
obtained in 65% yield as the sole product without detection
of 5 (Table 1, entry 2). Changing the tributyl group on the
Scheme 2.

C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
2499
i
, TMSCuCH, Pr
SnH, THF, 55 8C, 83%.
Scheme 3. Reagents and conditions: (a) Pd(PPh
)
3
)
c) Pd(PPh Cl , PhSnBu , THF, reflux, 76%; (d) Bu
2
Cl
2
2
NH, Cul, THF, rt, 98%; (b) Pd(PPh
3
)
2
Cl , (a-ethoxyvinyl)SnMe
2
3
, THF, 65 8C, 84%;
(
3
2
2
3
3
8
substitution than the silyl group, and (ii) that the C–Ge bond
would be stronger than the C–Sn bond and could tolerate
the PKR conditions (Scheme 2). Thus, the acetylide,
generated from 3, was trapped by treatment with trimethyl-
germyl bromide to give 8 in 88% yield, which was
subsequently exposed to Co (CO) . The resulting cobalt
Compound 9 was treated with NIS in refluxing 1,2-di-
chloroethane for 36 h to furnish 7 in 90% yield. It could be
predicted that the conversion of 9 to 7 required a higher
reaction temperature compared to the transformation of the
stannylated compound 4a to 7. It should be noted that the
transformation of 8 to 7 via 9 under these conditions was
reproduced several times.
2
8
1
1
complex was heated in acetonitrile to produce exclusively
in 85% overall yield. No formation of 5 or 6 could be
9
˚
detected in the reaction mixture. The 4 A molecular sieves
were not necessary in this case (Table 1, entry 2).
With the iodo derivative 7 in hand, we next examined the
conversion of the iodo group on the vinyl moiety of 7 to
n
Scheme 4. Reagents and conditions: (a) BuLi, Me
3
GeBr, THF, 278 8C, 14 (90%), 18 (81%), 22 (91%), 29 (97%); (b) TBAF, AcOH, THF, 0 8C, 24 (85%),;
2 2 2
(c) Ac O, DMAP, CH Cl , 0 8C, (72%).

2500
C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
suitable functionalities (Scheme 3). Introduction of carbon
side chains to the C -position was realized by palladium-
catalyzed coupling with trimethylsilylacetylene,
a-(ethoxyvinyl)trimethylstannane and tributylphenyl-
stannane to produce the corresponding coupling products
adjustment of the protecting group of 30 from the bulky
silyl group to the less sterically hindered acetyl group
(compound 31) shortened its reaction time (24 h) and gave
a similar yield.
2
1
2
16
1
C -unsubstituted bicyclo[3.3.0]octenone derivative 5,
0, 11, and 12 in 98, 84, and 76% yield, respectively. The
The final phase of this study was the successful application
of this procedure to the synthesis of the bicyclo[4.3.0]
skeleton. The homologated enyne 35 possessing the
trimethylgermyl group underwent the ring-closing reac-
2
which had previously been nonstereoselectively obtained
2
in 83% yield by the PKR of 3, could now be formed
exclusively upon exposure of 7 to Bu SnH (Scheme 2).
1
3
tion to provide the bicyclo[4.3.0]nonenone derivative 36,
which was then transformed to the corresponding iodo
derivative 37 in 92% yield. On the basis of the above-
mentioned preparation of compounds 9, 23, and 30, it is
3
We next investigated the PKR of several other enynes
having trimethylgermyl functionality at the triple bond
terminus to confirm the generality of this newly developed
procedure. Scheme 4 summarizes our preparation of several
1
1
therefore not surprising that the PKR of 39 produced
40 exclusively in 95% yield. A control experiment using
the unsubstituted enyne 38 produced a mixture of 42
and its epimer in 77% yield in a ratio of 92 to 8. The
bicyclic derivative 40 was converted to the iodo derivative
43 in 95% yield when heated with NIS in dichloroethane
for 72 h. Treatment of the alcohol (compound 41),
prepared by removal of the bulky silyl group, shortened
the reaction to less than one tenth the time (5.5 h),
although the yield was somewhat lower (44, 83%)
(Scheme 5).
1
3
bicyclo[3.3.0]octenone derivatives. The PKR of the
simple malonate derivative 14 possessing the trimethyl-
germyl functionality provided, in 67% yield, the corre-
sponding bicyclic compound 15, which was subsequently
converted to the iodo derivative 16 in 82% yield. Under
1
4
PKR conditions, the enyne derivative 18 with a methyl
group on the olefin moiety produced the desired 19,
although the yield (49%) was somewhat lower. Prolonged
treatment of 19 with NIS furnished 20 in 91% yield,
indicating tolerance of the 1,1-disubstituted olefin function-
ality in this transformation. Exclusive formation of 23 was
According to the procedure described in Scheme 3, the
introduction of various carbon units at the C -position of 37
1
1
realized by the PKR of 22, similar to the case of
compound 9. The enyne 21 without a terminal trimethyl-
9
1
2
was achieved in the presence of a palladium catalyst to
furnish compounds 45, 46, and 47 in high yields. Reduction
of 37 to 48 was also realized in 87% yield, as shown in
Scheme 6.
1
1
germyl group was submitted to the PKR conditions as a
control experiment to afford a mixture of 25 along with its
epimer in 79% yield in a ratio of 72 to 28. Thus,
trimethylgermyl group was again found to govern the
stereochemical outcome in this ring-closing reaction.
Conversion of 23 into 26 under standard conditions required
a relatively longer reaction time. In order to make the
reaction time shorter, 23 was first desilylated to give 24,
which was subjected to the standard iodination conditions.
Complete consumption of the starting material 24 was
In summary, we have developed the PKR of enynes having
a trimethylgermyl group at the alkyne terminus where the
stereoselective construction of the bicyclic compounds was
achieved. The trimethylgermyl moiety at the a position to
the carbonyl functionality of the resulting bicyclo[3.3.0]-
octenone and bicyclo[4.3.0]nonenone frameworks could be
converted into an iodo functionality by simple treatment
with NIS in refluxing 1,2-dichloroethane. Thus, this
procedure provides a new utilization of the trimethylgermyl
group in PKR as a latent functional group. Further
elaboration is still required and is underway in our
laboratory.
1
5
achieved within 2 h, but the yield was poor (35%).
1
1
Exclusive construction of 30 (86%) from 29 was followed
by conversion of the trimethylgermyl group to the iodo
moiety to produce 32 in good yield (58%). A prolonged
reaction time was required to complete the transformation
of 30 into 32 under standard conditions (two weeks). Thus,
n
Scheme 5. Reagents and conditions: (a) BuLi, Me
3
GeBr, THF, 278 8C, 35 (80%), 39 (93%); (b) TBAF, AcOH, THF, 0 8C, (87%).

C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
2501
i
, TMSCuCH, Pr
SnH, THF, 55 8C, 87%.
Scheme 6. Reagents and conditions: (a) Pd(PPh
(
3
)
c) Pd(PPh Cl , PhSnBu , THF, reflux, 88%; (d) Bu
2
Cl
2
2
NH, Cul, THF, rt, 99%; (b) Pd(PPh
3
)
2
Cl , (a-ethoxyvinyl)SnMe
2
3
, THF, 65 8C, 87%;
3
)
2
2
3
3
1
2
. Experimental
H NMR d 4.34–4.31 (1H, m), 4.17 (1H, dd, J¼6.8,
2
.9 Hz), 3.32–3.24 (1H, m), 2.67 (1H, dd, J¼17.6, 6.8 Hz),
Infrared spectra were measured with a Shimazu IR-460
spectrometer in CHCl , mass spectra with a Hitachi M-80
2.57 (1H, ddd, J¼13.2, 10.3, 6.4 Hz), 2.05 (1H, dd, J¼17.6,
3.4 Hz),1.53–1.45 (6H, m), 1.31 (6H, sex, J¼7.3 Hz), 1.11
(1H, ddd, J¼13.2, 8.3, 2.9 Hz), 1.04 (6H, t, J¼7.3 Hz), 0.88
(9H, t, J¼7.3 Hz), 0.87 (9H, s), 0.83 (9H, s), 0.13 (3H, s),
3
1
and JEOL GC mate mass spectrometers, H NMR spectra
with JEOL JNM-EX270 and JNM-GSX500 spectrometers
for samples in CDCl , using either tetramethylsilane (for
3
1
3
0.07 (3H, s), 0.05(3H, s), 0.03 (3H, s); C NMR d 216.5,
193.8, 139.7, 80.3, 77.0, 44.5, 42.8, 39.6, 29.1, 27.3, 25.8,
25.6, 18.0, 17.9, 13.6, 9.8, 24.2, 24.3, 24.6, 24.8; MS m/z
compounds without a silyl group) or CHCl (7.26 ppm)
3
(
for compounds with a silyl group) as an internal standard,
1
3
þ
and C NMR spectra with JEOL JNM-EX270 and JNM-
GSX500 spectrometers in CDCl with CDCl (77.00 ppm)
672 (M , 0.46). HRMS calcd for C H O Si Sn 672.3416,
2
Found 672.3431.
3
2
64
3
3
3
as an internal reference. All reactions were carried out under
a nitrogen atmosphere otherwise stated. Silica gel (Silica gel
2.1.2. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)-
2-(trimethylstannyl)bicyclo[3.3.0]oct-1-en-3-one (4b).
Colorless oil; [a] ¼þ85.0 (c 0.32, CHCl ); IR 1682,
60, 230–400 mesh, Merck) was used for chromatography.
Organic extracts were dried over anhydrous Na SO .
2
8
2
4
D
3
1 1
1
614 cm2 ; H NMR d 4.37–4.33 (1H, m), 4.20–4.14 (1H,
2
.1. General procedure for PKR of stannylated enynes
m), 3.31–3.24 (1H, m), 2.69 (1H, dd, J¼17.6, 6.8 Hz), 2.57
(
1H, ddd, J¼13.2, 10.3, 6.4 Hz), 2.06 (1H, dd, J¼17.6,
Conditions A. To a solution of enyne 3 in dry THF (0.1 M)
was dropwise added n-BuLi in hexane (1.5 equiv.) at 0 8C.
After stirring for 1 h, R SnCl (2.0 equiv.) was added to the
reaction, which was stirred at the same temperature for 1 h.
The reaction was quenched by addition of saturated aqueous
NH Cl, extracted with Et O, which was then washed with
3.4 Hz), 1.15 (1H, ddd, J¼13.2, 7.3, 2.0 Hz), 0.87 (9H, s),
0.82 (9H, s), 0.27 (9H, s), 0.12 (3H, s), 0.05 (3H, s), 0.04
(3H, s), 0.03 (3H, s); C NMR d 239.5, 216.3, 194.1, 139.4,
80.1, 76.5, 44.6, 42.5, 39.2, 25.7, 25.6, 18.0, 17.8, 24.3,
1
3
3
þ
C H O Si Sn 542.2007, Found 542.1977.
24.4, 24.6, 24.7; MS m/z 542 (M , 13.7). HRMS calcd for
4
2
23 46
3
2
H O and brine, dried and concentrated to dryness. The
2
residue was directly used for the next PKR without further
purification. To a solution of the crude residue in Et O
2.1.3. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)-
2-(triphenylstannyl)bicyclo[3.3.0]oct-1-en-3-one (4c).
2
2
6
(
mixture was stirred for 1 h. Et O was evaporated and the
0.1 M) was added Co (CO) (1.5 equiv.) at rt and the
Colorless oil; [a] ¼þ90.9 (c 0.3, CHCl ); IR 1686,
2
8
D
3
1616 cm2 ; H NMR d 7.62–7.60 (6H, m), 7.37–7.35
(9H, m), 4.29–4.25 (1H, m), 4.11 (1H, dd, J¼6.4, 2.0 Hz),
3.48–3.42 (1H, m), 2.80 (1H, dd, J¼18.1, 6.8 Hz), 2.62
(1H, ddd, J¼13.2, 10.3, 6.4 Hz), 2.20 (1H, dd, J¼18.1,
3.4 Hz), 1.21 (1H, ddd, J¼13.2, 7.3, 2.0 Hz), 0.80 (9H, s),
1
1
2
residue was passed through a short pad of silica gel with
hexane to give the cobalt complexed enyne derivative. A
solution of the cobalt complex in acetonitrile (0.05 M) was
heated at 50–55 8C for 1 h. The reaction mixture was
filtered through a short pad of celite, washed with AcOEt,
and concentrated to dryness. Chromatography of the residue
1
3
0.75 (9H, s), 0.02 (6H, s), 20.32 (3H, s), 20.33 (3H, s);
C
NMR d 215.5, 196.6, 137.8, 137.4, 137.3, 137.2, 129.1,
128.9, 128.1, 80.3, 75.6, 44.2, 4.6, 39.5, 25.8, 25.5, 17.9,
2
b
with 2–5% AcOEt in hexane afforded 4, 5, and 6.
þ
1
7.7, 24.6, 24.7, 24.8; MS m/z 732 (M , 32.6). HRMS
Conditions B. The PKR of the stannylated enynes was
calcd for C H O Si Sn 732.2477, Found 732.2482.
38 52 3 2
˚
carried out in the presence of 4A-MS. The results were
summarized in Table 1.
2.1.4. Dimer 6. Colorless oil; IR 1703, 1614 cm2 ; H
NMR d 4.96 (2H, d, J¼2.9 Hz), 4.28 (2H, ddd, J¼8.3, 6.8,
2.9 Hz), 3.15–3.08 (2H, m), 2.68 (2H, dd, J¼18.1, 6.8 Hz),
2.50 (2H, dt, J¼12.2, 6.8 Hz), 2.18 (2H, dd, J¼18.1,
3.4 Hz), 1.24 (2H, dt, J¼12.2, 8.3 Hz), 0.90 (18H, s), 0.81
1
1
2
(
.1.1. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)-2-
tributylstannyl)bicyclo[3.3.0]oct-1-en-3-one (4a). Color-
2
9
21
less oil; [a] ¼þ78.9 (c 0.64, CHCl ); IR 1682, 1612 cm
;
D
3

2502
C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
(18H, s), 0.10 (6H, s), 0.08 (6H, s), 0.06 (6H, s), 20.07 (6H,
s); C NMR d 207.1, 182.0, 129.1, 83.6, 76.6, 41.8, 40.9,
AcOEt (50:1) gave 9 (51.5 mg, 85%) as a colorless oil:
25
13
21 1
[a] ¼þ95.9 (c 0.5, CHCl ); IR 1686, 1622 cm ; H NMR
D
3
3
m/z 762 (M , 12.6). FABHRMS calcd for C H O Si
7
9.0, 25.9, 25.7, 17.97, 17.92, 23.9, 24.5, 24.6, 24.7; MS
þ
63.4641, Found 763.4606.
d: 4.48–4.44 (1H, m), 4.16 (1H, d, J¼5.9 Hz), 3.24–3.19
(1H, m), 3.63 (1H, dd, J¼17.6, 6.8 Hz), 2.55 (1H, ddd,
J¼13.2, 10.3, 5.9 Hz), 3.63 (1H, dd, J¼17.6, 3.9 Hz), 1.13
4
0
75
6
4
(
1H, ddd, J¼13.2, 7.3, 2.0 Hz), 0.87 (9H, s), 0.82 (9H, s),
2
.1.5. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)-2-
iodobicyclo[3.3.0]oct-1-en-3-one (7). From compound 4a.
0.36 (9H, s), 0.13 (3H, s), 0.07 (3H, s), 0.04 (3H, s), 0.02
(3H, s); C NMR d 215.0, 191.2, 138.7, 80.0, 75.7, 45.0,
41.4, 38.9, 25.7, 25.6, 17.9, 17.8, 21.2, 24.3, 24.6, 24.7;
1
3
2
1
A solution of 4a (175 mg, 2.61£10 mmol) and I2
2
1
þ
500.2197, Found 500.2195.
(
133 mg, 5.24£10 mmol) in dry THF (1.3 mL) was
MS m/z 500 (M , 27.0). HRMS calcd for C H GeO Si
3
2
3
46
2
stirred at rt overnight. The reaction mixture was diluted
with Et O, washed with saturated aqueous Na S O and
brine, dried, and concentrated to dryness. Chromatography
2
2 2 3
2.1.8. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)-2-[2-
(trimethylsilyl)ethyn-1-yl]bicyclo[3.3.0]oct-1-en-3-one
of the residue with hexane–AcOEt (32:1) gave 7 (133 mg,
8
2
22
quant.) as a colorless oil: [a] ¼þ138.3 (c 0.43, CHCl ); IR
(10). To a solution of 7 (20.0 mg, 3.93£10 mmol),
D
3
1
715, 1632 cm2 ; H NMR d 4.40–4.35 (1H, m), 4.24 (1H,
1
1
(trimethylsilyl)acetylene (0.8£10 mL, 5.90£10 mmol),
Pd(PPh ) Cl
3 2 2
22
22
2
3
ddd, J¼6.4, 4.4, 2.0 Hz), 3.31–3.26 (1H, m), 2.92 (1H, dd,
(1.7 mg, 2.36£10 mmol), and CuI
2
3
J¼18.1, 6.8 Hz), 2.61 (1H, ddd, J¼13.2, 9.8, 6.4 Hz), 2.23
(0.23 mg, 1.18£10 mmol) in THF (0.4 mL) was added
2
1
(
1H, dd, J¼18.1, 2.9 Hz), 1.23 (1H, ddd, J¼13.2, 8.8,
i-Pr NH (0.06 mL, 3.93£10 mmol) at rt. The reaction
2
4
0
8
.4 Hz), 0.89 (9H, s), 0.85 (9H, s), 0.20 (3H, s), 0.14 (3H, s),
.08 (3H, s), 0.05 (3H, s); C NMR d 204.8, 187.8, 96.3,
0.8, 78.2, 42.2, 41.5, 39.2, 25.7, 18.0, 17.8, 24.1, 24.5,
mixture was stirred for 2 h, passed through a short pad of
celite, and concentrated to dryness. Chromatography of the
residue with hexane–AcOEt (5:1) gave 10 (18.5 mg, 98%)
1
3
þ
28
D
2
calcd for C H IO Si 509.1404, Found 509.1409
4.6, 24.8; FABMS m/z 509 (M þ1, 12.5). FABHRMS
as a colorless oil: [a] ¼þ130.7 (c 0.26, CHCl ); IR 2158,
3
1717, 1639 cm2 ; H NMR d 4.58–4.51 (1H, m), 4.28–
1 1
2
0
38
3
2
þ
(
M þ1).
4.25 (1H, m), 3.20–3.15 (1H, m), 2.77 (1H, dd, J¼18.6,
6
.8 Hz), 2.55 (1H, ddd, J¼12.7, 9.3, 6.3 Hz), 2.15 (1H, dd,
2
2
From compound 9. A solution of 9 (6.8 mg, 1.36£10
J¼18.6, 3.4 Hz), 1.13 (1H, ddd, J¼12.7, 9.3, 4.9 Hz), 0.89
2
2
mmol) and N-iodosuccinimide (4.6 mg, 2.04£10 mmol)
in 1,2-dichroloethane (0.3 mL) was refluxed for 36 h in the
dark. The reaction mixture was quenched by addition of
water, extracted with CH Cl , which was washed with
(9H, s), 0.85 (9H, s), 0.22 (9H, s), 0.18 (3H, s), 0.11 (3H, s),
1
3
0.08 (3H, s), 0.05 (3H, s); C NMR d 206.2, 186.4, 122.7,
103.9, 94.7, 82.1, 75.7, 43.1, 39.3, 39.1, 25.73, 25.70, 18.0,
17.9, 20.2, 24.4, 24.6, 24.8, 24.9; FABMS m/z 479
2
2
þ
water and brine, dried and concentrated to dryness.
Chromatography of the residue gave 7 (6.2 mg, 90%).
(M þ1, 3.7). FABHRMS calcd for C H O Si 479.2833,
2
5
47
3
3
Found 479.2846.
2.1.6. (4R,5R)-4,5-Bis(tert-butyldimethylsiloxy)-7-(tri-
methylgermyl)hep-1-en-6-yne (8). To a solution of 3
2.1.9. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)-2-(1-
ethoxyethen-1-yl)bicyclo[3.3.0]oct-1-en-3-one (11).
A
2
1
21
(
50.0 mg, 1.41£10 mmol) in THF (1.4 mL) was added
solution of 7 (99.2 mg, 1.95£10 mmol), Pd(PPh ) Cl
3
2
2
2
1
22
n-BuLi in hexane (1.30 M, 0.16 mL, 2.11£10 mmol) at
(13.7 mg, 1.95£10 mmol) and (a-ethoxyvinyl)trimethyl-
2
1
0
8C and the reaction mixture was stirred for 1 h at the same
tin (183 mg, 7.80£10 mmol) in THF (1.0 mL) was heated
at 65 8C for 6.5 h. The reaction mixture was diluted with
AcOEt, which was washed with water and brine, dried, and
concentrated to dryness. Chromatography of the residue
with hexane–AcOEt (50:1) gave 11 (74.1 mg, 84%) as a
2
1
temperature. Me GeBr (0.04 mL, 2.82£10 mmol) was
3
then added to a solution of the acetylide in THF and stirring
was continued for 30 min at 0 8C. The reaction mixture was
quenched by addition of saturated aqueous NH Cl,
4
extracted with Et O, washed with water and brine, dried,
2
and concentrated to dryness. Chromatography of the residue
with hexane gave 8 (58.4 mg, 88%) as a colorless oil:
2
8
colorless oil: [a] ¼þ114 (c 0.28, CHCl ); IR 1701,
D
3
1651 cm2 ; H NMR d 5.24 (1H, d, J¼2.4 Hz), 5.03–
4.96 (1H, m), 4.37 (1H, d, J¼2.4 Hz), 4.20 (1H, dd, J¼6.3,
2.4 Hz), 3.88–3.78 (2H, m), 3.14–3.08 (1H, m), 2.78 (1H,
dd, J¼17.6, 6.8 Hz), 2.58 (1H, ddd, J¼13.7, 10.3, 6.3 Hz),
2.17 (1H, dd, J¼17.6, 3.4 Hz), 1.37 (3H, t, J¼7.3 Hz), 1.14
(1H, ddd, J¼13.7, 7.8, 2.4 Hz), 0.86 (9H, s), 0.81 (9H, s),
1
1
2
6
21
1
[
a] ¼20.20 (c 0.5, CHCl ); IR 2170, 1639 cm ; H
D
3
1
NMR H NMR d 5.87 (1H, ddt, J¼17.6, 10.3, 7.3 Hz), 5.09–
5
5
0
0
6
.01 (2H, m), 4.29 (1H, d, J¼5.4 Hz), 3.63 (1H, ddd, J¼6.8,
.4, 4.4 Hz), 2.48–2.33 (2H, m), 0.91 (9H, s), 0.90 (9H, s),
.33 (9H, s), 0.14 (3H, s), 0.10 (3H, s), 0.07 (3H, s),
1
3
0.11 (3H, s), 0.04 (3H, s), 0.03 (3H, s), 0.00 (3H, s);
C
1
3
.06 (3H, s); C NMR d 135.7, 116.7, 104.2, 90.2, 75.1,
7.1, 37.3, 25.93, 25.88, 18.3, 18.1, 20.4, 24.3, 24.42,
NMR d 205.6, 177.9, 153.5, 130.9, 89.0, 81.7, 76.2, 62.0,
44.7, 39.0, 37.7, 25.9, 25.8, 18.1, 18.0, 14.6, 24.4, 24.6,
þ
þ
C H O Si 453.2856, Found 453.2858.
24.43, 24.6; MS m/z 472 (M , 41.0). HRMS calcd for
C H GeO Si 472.2248, Found 472.2244.
24.7; FABMS m/z 453 (M þ1, 4.1). FABHRMS calcd for
2
2
46
2
2
24 45
4
2
2
(
.1.7. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)-2-
trimethylgermyl)bicyclo[3.3.0]oct-1-en-3-one (9). Accor-
ding to the general procedure for PKR (Conditions A), 8
2.1.10. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)-2-
phenylbicyclo[3.3.0]oct-1-en-3-one (12). A solution of 7
2
2
(17.6 mg, 3.46£10 mmol), Pd(PPh ) Cl
(2.5 mg,
21
3
2
2
2
1
23
(
(
58.0 mg, 1.23£10 mmol) was treated with Co (CO)
3.46£10 mmol) and Bu SnPh (45 mL, 1.38£10
2
8
3
2
1
63.0 mg, 1.85£10 mmol). The resulting cobalt complex
mmol) in THF (0.3 mL) was refluxed for 5 h. The reaction
mixture was diluted with AcOEt, which was washed with
water and brine, dried, and concentrated to dryness.
was heated at 70–75 8C in acetonitrile (1.2 mL) for 3 h.
Work-up and chromatography of the residue with hexane–

C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
2503
1
3
Chromatography of the residue with hexane–AcOEt (26:1)
2
2.83 (2H, s), 1.65 (3H, s), 0.30 (9H, s); C NMR d 170.5,
139.8, 116.0, 100.0, 88.2, 56.7, 52.5, 39.4, 23.8, 23.1, 20.4.
6
D
gave 12 (12.0 mg, 76%) as a colorless oil: [a] ¼ þ88.6 (c
þ
C H GeO 343.0964, Found 343.0967.
0.42, CHCl ). FABHRMS calcd for C H O Si 459.2750,
Found 459.2762. Spectral data were shown in ref 2b.
FABMS m/z 343 (M þ1, 3.7). FABHRMS calcd for
3
26 43
3
2
1
5
25
4
2.1.11. (5R,7R,8R)-7,8-Bis(tert-butyldimethylsiloxy)bi-
cyclo[3.3.0]oct-1-en-3-one (5). A solution of 7 (51.0 mg,
2.1.16. 7,7-Bis(methoxycarbonyl)-5-methyl-2-(trimethyl-
germyl)bicyclo[3.3.0]oct-1-en-3-one (19). To a solution of
2
1
21
22
1
.00£10 mmol), Bu SnH (0.13 mL, 5.01£10 mmol)
enyne 18 (32.4 mg, 9.50£10 mmol) in DME (1.0 mL)
3
2
1
and AIBN (a catalytic amount) in THF (0.2 mL) was heated
at 55 8C for 1 h. The reaction mixture was diluted with
AcOEt, which was washed with water and brine, dried, and
concentrated to dryness. Chromatography of the residue
with hexane–AcOEt (20:1) gave 5 (32.0 mg, 83%) as a
was added Co (CO) (39.0 mg, 1.14£10 mmol). The
2
8
reaction mixture was stirred at rt for 15 min, to which
2
1
PhSMe (0.04 mL, 3.33£10 mmol) was added. After
being stirred for 24 h at 70 8C, the reaction mixture was
passed through a short pad of celite and concentrated to
dryness. Chromatography of the residue with hexane–
AcOEt (10:1) gave 19 (17.1 mg, 49%) as colorless needles:
2
6
colorless oil: [a] ¼þ102.5 (c 0.3, CHCl ). FABHRMS
D
3
calcd for C H O Si 383.2437, Found 383.2432. Spectral
2
2
0
39
3
2
1
data are shown in Ref. 2b.
mp 67–68 8C (hexane–Et O): IR 1732, 1693, 1618 cm
2
;
1
H NMR d 3.79 (3H, s), 3.71 (3H, s), 3.41, 3.23 (2H, AB-q,
J¼17 Hz), 2.60 (1H, d, J¼14 Hz), 2.34 (2H, s), 2.13 (1H, d,
2
.1.12. Dimethyl 2-allyl-2-[3-(trimethylgermyl)-2-pro-
1
3
pyn-1-yl]malonate (14). According to the procedure
described for preparation of 8 from 3, 14 (1.07 g, 90%)
J¼14 Hz), 1.11 (3H, s), 0.33 (9H, s); C NMR d 212.5,
193.7, 172.2, 172.0, 59.8, 53.3, 53.2, 52.5, 50.9, 44.3, 34.8,
27.0, 21.5; FABMS m/z 371 (M þ1, 25.4). FABHRMS
1
7
þ
calcd for C H GeO 371.0914, Found 371.0939.
was obtained from 13 (794 mg, 3.78 mmol) a colorless oil:
2
1 1
IR 2174, 1736, 1641 cm ; H NMR d 5.63 (1H, ddt, J¼10,
1
6
25
5
1
7, 7.6 Hz), 5.19–5.09 (2H, m), 3.72 (6H, s), 2.81–2.78
1
3
(
4H, m), 0.31 (9H, s); C NMR d 170.2, 131.9, 119.5, 99.5,
2.1.17. 2-Iodo-7,7-bis(methoxycarbonyl)-5-methylbicyclo-
[3.3.0]oct-1-en-3-one (20). According to the procedure
described for preparation of 7 from 9, 20 (74.8 mg, 91%)
þ
0.1). FABHRMS calcd for C H GeO 329.0808, Found
29.0814.
88.0, 57.1, 52.5, 36.5, 23.9, 20.3; FABMS m/z 329 (M þ1,
1
3
1
4
23
4
2
1
was obtained from 19 (80.1 mg, 2.17£10 mmol) as
colorless needles: mp 116–117 8C (hexane–Et O): IR
2
1732, 1720, 1636 cm2 ; H NMR d 3.80 (3H, s), 3.73
1
1
2.1.13. 7,7-Bis(methoxycarbonyl)-2-(trimethylgermyl)-
bicyclo[3.3.0]oct-1-en-3-one (15). To a solution of enyne
(3H, s), 3.56 (1H, d, J¼18 Hz), 3.13 (1H, d, J¼18 Hz),
13
2
1
1
4 (32.8 mg, 1.00£10 mmol) in DME (1.0 mL) was
2.66 (1H, d, J¼14 Hz), 2.59, 2.47 (2H, AB-q, J¼18 Hz),
C NMR d
202.9, 191.0, 171.7, 171.3, 94.0, 58.8, 53.44, 53.41,
2
1
added Co (CO) (41.2 mg, 1.20£10 mmol). The reaction
2.27 (1H, d, J¼14 Hz), 1.15 (3H, s);
2
8
mixture was heated at 70 8C under an atmosphere of CO for
4 h, passed through a short pad of celite, and concentrated
to dryness. Chromatography of the residue with hexane–
þ
2
51.5, 49.5, 44.8, 36.4, 26.7; MS m/z 378 (M , 41.4). Anal.
Calcd for C H IO : C, 41.29; H, 4.00. Found: C, 41.49; H,
4.13.
1
3
15
5
AcOEt (10:1) gave 15 (23.9 mg, 67%) as colorless plates:
1
2
mp 70–71 8C (hexane–Et O); IR 1732, 1686, 1614 cm
2
;
1
H NMR d: 3.79 (3H, s), 3.75 (3H, s), 3.28, 3.16 (2H, AB-q,
J¼19 Hz), 3.10–2.98 (1H, m), 2.89–2.75 (1H, m), 2.59
2.1.18. 5-(tert-Butyldimethysiloxy)hept-1-en-6-yne (21).
A solution of DMSO (9.9 mL, 139 mmol) in CH Cl
2
2
(
(
1H, dd, J¼6.6, 17 Hz), 2.07 (1H, dd, J¼4.0, 17 Hz), 1.68
(30 mL) was gradually added to a solution of oxalyl
chloride (6.1 mL, 69.7 mmol) in CH Cl (40 mL) at
1
3
1H, t, J¼13 Hz), 0.34 (9H, s); C NMR d 212.6, 190.7,
2
2
1
2
71.9, 171.3, 137.8, 60.6, 53.1, 52.9, 46.4, 42.5, 38.6, 35.9,
1.8; FABMS m/z 357 (M þ1, 21.8). FABHRMS calcd for
278 8C. After stirring of the CH Cl solution for 15 min,
2 2
a solution of 4-penten-1-ol (3.00 g, 34.8 mmol) in CH Cl
2 2
þ
C H GeO 357.0757, Found 357.0758.
(30 mL) was added and the reaction was stirred at 278 8C
for 1 h. Et N (29.1 mL, 209 mmol) was added to the
1
5
23
5
3
2
.1.14. 2-Iodo-7,7-bis(methoxycarbonyl)bicyclo[3.3.0]-
reaction mixture, which was then gradually warmed to rt
and diluted with CH Cl . The CH Cl solution was washed
oct-1-en-3-one (16). According to the procedure described
for preparation of 7 from 9, 16 (14.0 mg, 82%) was obtained
2
2
2
2
successively with water and brine, dried and concentrated to
leave the crude aldehyde. n-BuLi in hexane (1.23 M,
42.5 mL, 52.2 mmol) was added to a solution of (trimethyl-
silyl)acetylene (7.4 mL, 52.2 mmol) in THF (180 mL) at
278 8C and the solution was stirred for additional 1 h. A
solution of the crude aldehyde derived from 4-penten-1-ol in
THF (60 mL) was then added to a solution of the acetylide
in THF at 278 8C and stirring was continued for 1 h at the
same temperature. The reaction mixture was quenched by
2
2
from 15 (17.4 mg, 4.78£10 mmol) as colorless needles:
2
1
mp 90–91 8C (hexane–Et O); IR 1732, 1720, 1634 cm
2
;
1
H NMR d 3.80 (3H, s), 3.77 (3H, s), 3.39, 3.13 (2H, AB-q,
J¼20 Hz), 3.26–3.12 (1H, m), 2.93–2.80 (2H, m), 2.25
1
3
(
1H, dd, J¼3.0, 18 Hz), 1.80 (1H, t, J¼13 Hz); C NMR d
2
3
03.2, 188.1, 171.5, 170.7, 94.7, 59.7, 53.4, 53.2, 46.4, 39.9,
9.2, 37.3; MS m/z 364 (M , 20.5). Anal. Calcd for
þ
C H IO : C, 39.58; H, 3.60. Found: C, 39.57; H, 3.61.
1
2
13
5
addition of saturated aqueous NH Cl and extracted with
4
2
.1.15. Dimethyl 2-(2-methyl-2-propen-1-yl)-2-[3-(tri-
AcOEt, which was washed successively with water and
brine, dried and concentrated to dryness. Chromatography
of the residue with hexane–AcOEt (10:1) gave the alcohol
(5.27 g, 83%) as a pale yellow oil. To a solution of the crude
methylgermyl)-2-propyn-1-yl]malonate (18). According
to the procedure described for preparation of 8 from 3,
1
8
1
2
1
8 (742 mg, 81%) was obtained from 17 (605 mg,
1
.70 mmol) as a colorless oil: IR 2174, 1740, 1645 cm2
H NMR d 4.90–4.83 (2H, m), 3.72 (6H, s), 2.84 (2H, s),
;
alcohol (1.00 g, 5.48 mmol) and Et N (2.3 mL, 16.5 mmol)
3
in CH Cl (50 mL) was added TBSOTf (1.9 mL,
2
2

2504
C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
p
p
8
3
.23 mmol) at 0 8C. The reaction mixture was stirred for
0 min at rt, quenched by addition of water, and extracted
2.1.22. (5R ,8R )-8-(tert-Butyldimethylsiloxy)bicyclo-
[3.3.0]oct-1-en-3-one (25). According to the procedure
described for preparation of 9 from 8, 25 (96.1 mg, 74%)
was obtained along with its stereoisomer (25: epimer¼
with CH Cl . The extract was washed successively with
2
2
water and brine, dried and concentrated to dryness.
Chromatography of the residue with hexane gave the silyl
ether (1.17 g, 72%). To a solution of the silyl ether (605 mg,
2
1
72:28) from 21 (116 mg, 5.17£10 mmol). Compound 25
was a colorless oil: IR 1703, 1636 cm2 ; H NMR d 5.92
(1H, d, J¼2.3 Hz), 4.75 (1H, dd, J¼5.5, 5.6 Hz), 3.25–3.15
(1H, m), 2.67 (1H, dd, J¼6.6, 18 Hz), 2.37–2.16 (2H, m),
2.06 (1H, dd, J¼3.0, 18 Hz), 1.97–1.83 (1H, m), 1.17–1.04
1 1
2
.04 mmol) in MeOH (20 mL) was added K CO (282 mg,
2 3
2.04 mmol) at rt. The reaction mixture was stirred for 5 h at
the same temperature. MeOH was evaporated off, and the
1
3
residue was diluted with Et O, washed with water and brine,
2
(1H, m), 0.89 (9H, s), 0.11 (3H, s), 0.07 (3H, s); C NMR d
dried and concentrated to dryness. Chromatography of the
residue with hexane gave 21 (380 mg, 83%) as a colorless
211.3, 188.4, 125.0, 68.4, 42.9, 42.8, 36.9, 28.4, 25.7, 18.1,
þ
24.6, 24.8; MS m/z 252 (M , 6.7). Anal. Calcd for
2
1 1
oil: IR 3306, 1639 cm ; H NMR d 5.82 (1H, ddt, J¼10,
C H O Si: C, 66.61; H, 9.58. Found: C, 66.34; H, 9.82.
1
4 24 2
Epimer of 25 was a colorless oil: IR 1701, 1636 cm2 ; H
NMR d 6.02 (1H, s), 4.96 (1H, dd, J¼4.9, 9.3 Hz), 2.96–
2.89 (1H, m), 2.64 (1H, dd, J¼6.3, 18 Hz), 2.40–2.31 (1H,
m), 2.16–2.08 (2H, m), 1.88–1.81 (1H, m), 1.57–1.42 (1H,
1 1
1
2
1
7, 6.6 Hz), 5.08–4.95 (1H, m), 4.36 (1H, dt, J¼6.6,
.0 Hz), 2.39 (1H, d, J¼2.0 Hz), 2.24–2.16 (2H, m), 1.81–
1
3
.73 (2H, m), 0.91 (9H, s), 0.14 (3H, s), 0.11 (3H, s);
C
NMR d 137.8, 115.0, 85.4, 72.2, 62.1, 37.7, 29.3, 25.8, 18.2,
4.5, 25.1. This crude 21 was directly converted into
compound 22.
1
3
2
m), 0.92 (9H, s), 0.12 (3H, s), 0.11 (3H, s); C NMR d
210.2, 192.3, 124.4, 70.5, 43.5, 41.7, 35.4, 29.0, 25.7, 18.2,
þ
24.8,-4.9; MS m/z 252 (M , 2.5). Anal. Calcd for
2
.1.19. 5-(tert-Butyldimethysiloxy)-7-(trimethylgermyl)-
C H O Si: C, 66.61; H, 9.58. Found: C, 66.33; H, 9.81.
14 24 2
hept-1-en-6-yne (22). According to the procedure described
for preparation of 8 from 3, 22 (512 mg, 91%) was obtained
from 21 (371 mg, 1.65 mmol) as a colorless oil: IR 2166,
p
p
2.1.23. (5R ,8R )-8-(tert-Butyldimethylsiloxy)-2-iodobi-
cyclo[3.3.0]oct-1-en-3-one (26). According to the pro-
cedure described for preparation of 7 from 9, 26 (17.2 mg,
639 cm2 ; H NMR d 5.82 (1H, ddt, J¼17, 10, 6.6 Hz),
1 1
1
5
22
.08–4.93 (2H, m), 4.35 (1H, t, J¼6.6 Hz), 2.23–2.13 (2H,
80%) was obtained from 23 (21.0 mg, 5.69£10 mmol) as
a colorless oil: IR 1715, 1628 cm2 ; H NMR d 4.69–4.65
(1H, m), 3.34–3.24 (1H, m), 2.89 (1H, dd, J¼6.6, 18 Hz),
2.43–2.14 (3H, m), 1.99–1.85 (1H, m), 1.25–1.04 (1H, m),
1 1
m), 1.86–1.68 (2H, m), 0.91 (9H, s), 0.33 (9H, s), 0.13 (3H,
s), 0.11 (3H, s); C NMR d 138.1, 114.8, 106.4, 88.7, 62.8,
1
3
3
7.8, 29.5, 25.9, 18.3, 20.3, 24.4, 24.9; FABMS m/z 343
þ
43.1512, Found 343.1525.
13
(
M þ1, 1.5). FABHRMS calcd for C H GeOSi
0.91 (9H, s), 0.18 (6H, s); C NMR d 205.1, 189.8, 95.2,
70.4, 44.9, 40.4, 36.6, 28.6, 25.8, 18.0, 24.2, 24.3; MS m/z
1
6 33
3
þ
6.13. Found: C, 44.56; H, 6.34.
3
78 (M , 0.3). Anal. Calcd for C H IO Si: C, 44.45; H,
1
4
23
2
p
.1.20. (5R ,8R )-8-(tert-Butyldimethylsiloxy)-2-(tri-
p
2
methylgermyl)bicyclo[3.3.0]oct-1-en-3-one (23). Accord-
ing to the procedure described for preparation of 9 from 8,
p
p
2.1.24. (5R ,8R )-8-Hydroxy-2-iodobicyclo[3.3.0]oct-1-
en-3-one (27). According to the procedure described for
preparation of 7 from 9, 27 (18.7 mg, 35%) was obtained
2
1
3 (320 mg, 87%) was obtained from 22 (341 mg,
.00 mmol) as a colorless oil: IR 1686, 1616 cm21; H
1
2
1
NMR d 4.81 (1H, dd, J¼3.3, 5.6 Hz), 3.25–3.14 (1H, m),
from 24 (52.0 mg, 2.04£10 mmol) as colorless needles:
;
2
2
1
2
.64 (1H, dd, J¼6.9, 18 Hz), 2.27–2.09 (2H, m), 2.04–1.82
mp 96–97 8C (hexane–Et O); IR 3418, 1715, 1628 cm
1
(
(
2H, m), 1.16–0.97 (1H, m), 0.88 (9H, s), 0.36 (9H, s), 0.12
3H, s), 0.10 (3H, s); C NMR d 215.1, 193.4, 137.1, 68.9,
H NMR d 4.33 (1H, t, J¼6.3 Hz), 3.32–3.21 (1H, m), 2.91
1
3
(1H, dd, J¼6.3, 18 Hz), 2.58–2.46 (1H, m), 2.35–2.17 (3H,
1
3
4
3.5, 43.4, 36.6, 28.0, 25.7, 17.9, 21.3, 23.8, 24.3;
m), 2.04–1.88 (1H, m), 1.25–1.05 (1H, m); C NMR d
204.8, 189.5, 96.0, 65.7, 45.5, 40.5, 35.2, 28.9; MS m/z 264
þ
C H GeO Si 371.1461, Found 371.1463.
FABMS m/z 371 (M þ1, 8.3). FABHRMS calcd for
þ
Found: C, 36.41; H, 3.57.
(M , 20.2). Anal. Calcd for C H IO : C, 36.39; H, 3.44.
8
1
7
33
2
9
2
p
.1.21. (5R ,8R )-8-Hydroxy-2-(trimethylgermyl)bicyclo-
p
2
[
(
3.3.0]oct-1-en-3-one (24). A mixture of TBAF in THF
1.00 M, 1.43 mL, 1.43 mmol) and AcOH (3 drops) was
2.1.25. 5-(tert-Butyldimethysiloxy)-4,4-dimethyl-7-(tri-
methylgermyl)hept-1-en-6-yne (29). According to the
procedure described for preparation of 8 from 3, 29
added to a solution of 23 (440 mg, 1.19 mmol) in THF
0.6 mL) at 0 8C. The reaction mixture was stirred for 30 h
6
(
(284 mg, 97%) was obtained from 28 (200 mg,
2
1
21
at the same temperature, quenched by addition of saturated
aqueous NH Cl, and extracted with Et O. The extract was
washed with water and brine, dried, and concentrated to
dryness. Chromatography of the residue with hexane–
AcOEt (4:1) gave 24 (257 mg, 85%) as a colorless oil: IR
3
3
(
1
7.92£10 mmol) as a colorless oil: IR 2166, 1638 cm
;
1
H NMR d 5.82 (1H, ddt, J¼6.3, 9.2, 17 Hz), 5.09–4.96
4
2
(2H, m), 4.00 (1H, s), 2.15–2.05 (2H, m), 0.91 (6H, s), 0.90
(9H, s), 0.33 (9H, s), 0.14 (3H, s), 0.09 (3H, s); C NMR d
135.5, 117.0, 105.1, 89.9, 71.0, 42.6, 39.0, 25.9, 22.7, 22.6,
1
3
2
1
1
þ
FABHRMS calcd for C H GeOSi 371.1825, Found
371.1862.
422, 1690, 1616 cm ; H NMR d 4.83 (1H, t, J¼5.6 Hz),
18.3, 20.3, 24.2, 25.1; FABMS m/z 371 (M þ1, 1.4).
.22–3.07 (1H, m), 2.65 (1H, dd, J¼6.3, 18 Hz), 2.50–2.38
1
8 37
1H, m), 2.29–2.17 (1H, m), 2.04 (1H, dd, J¼3.3, 18 Hz),
.96–1.81 (1H, m), 1.25 (1H, s), 1.17–1.00 (1H, m), 0.89
1
3
p
p
(
9H, s); C NMR d 215.1, 193.5, 138.2, 68.0, 44.5, 43.2,
6.3, 28.6, 21.5; FABMS m/z 257 (M þ1, 31.2).
2.1.26. (5R ,8R )-8-(tert-Butyldimethylsiloxy)-7,7-di-
methyl-2-(trimethylgermyl)bicyclo[3.3.0]oct-1-en-3-one
(30). According to the procedure described for preparation
of 9 from 8, 30 (656 mg, 86%) was obtained from 29
þ
FABHRMS calcd for C H GeO 257.0597, Found
3
1
1
19
2
2
57.0604.

C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
2505
(
1
2
707 mg, 1.92 mmol) as a colorless oil: IR 1686,
137.3, 115.0, 99.5, 88.0, 56.8, 52.5, 31.2, 28.3, 24.1, 20.3;
FABMS m/z 343 (M þ1, 12.7). FABHRMS calcd for
616 cm2 ; H NMR d 4.13 (1H, s), 3.43–3.35 (1H, m),
1
1
þ
C H GeO 343.0964, Found 343.0939.
.68 (1H, dd, J¼6.8, 18 Hz), 2.03 (1H, t, J¼12 Hz), 1.98
1
5
25
4
(
1H, dd, J¼3.4, 18 Hz), 1.13 (3H, s), 1.06 (1H, dd, J¼5.9,
1
0
4
3 Hz), 0.89 (9H, s), 0.76 (3H, s), 0.36 (9H, s), 0.11 (3H, s),
.02 (3H, s); C NMR d 214.9, 193.6, 136.9, 77.3, 45.6,
4.1, 42.3, 42.2, 28.5, 25.6, 24.0, 18.1, 21.3, 24.2, 24.8;
2.1.31. 3,3-Bis(methoxycarbonyl)-9-(trimethylgermyl)-
bicyclo[4.3.0]non-1(9)-en-8-one (36). According to the
procedure described for preparation of 15 from 14, 36
(410 mg, 78%) was obtained from 35 (484 mg, 1.42 mmol)
1
3
þ
FABMS m/z 397 (M þ1, 4.2). FABHRMS calcd for
C H GeO Si 397.1774, Found 397.1790.
1
as colorless needles: mp 74–75 8C (hexane–Et O); IR
2
9
37
2
1
1
1
732, 1686, 1603 cm2 ; H NMR d 3.76 (3H, s), 3.70 (3H,
p
p
2
.1.27. (5R ,8R )-8-Acetoxy-7,7-dimethyl-2-(trimethyl-
s), 3.60 (1H, dd, J¼1.7, 14 Hz), 2.70–2.44 (4H, m), 2.20–
germyl)bicyclo[3.3.0]oct-1-en-3-one (31). According to
the procedure described for preparation of 24 from 23, 30
(
sponding hydroxyl compound (118 mg, 77%). To a solution
2.06 (1H, m), 2.00–1.84 (2H, m), 1.40–1.20 (1H, m), 0.38
(9H, s); C NMR d 211.6, 182.8, 171.6, 170.1, 141.6, 56.7,
53.0, 52.6, 42.4, 41.8, 35.2, 30.9, 30.6, 20.9; FABMS m/z
1
3
2
1
216 mg, 5.43£10 mmol) was converted into the corre-
þ
371.0914, Found 371.0901.
371 (M þ1, 16.6). FABHRMS calcd for C H GeO
1
6
25
5
2
1
of the crude alcohol (68.6 mg, 2.42£10 mmol) and
2
1
DMAP (5.9 mg, 4.85£10 mmol) in CH Cl (2.4 mL)
2
2
2
1
was added acetic anhydride (0.05 mg, 4.84£10 mmol) at
2.1.32. 9-Iodo-3,3-bis(methoxycarbonyl)bicyclo[4.3.0]-
non-1(9)-en-8-one (37). According to the procedure
described for preparation of 7 from 9, 37 (70.3 mg, 92%)
0 8C. The reaction mixture was stirred for 40 min, quenched
by addition of saturated aqueous NaHCO , extracted with
3
2
1
CH Cl . The extract was washed with water and brine,
2
dried, and concentrated to dryness. Chromatography of the
residue with hexane–AcOEt (50:1) gave 31 (74.0 mg, 94%)
as a colorless oil: IR 1734, 1692, 1622 cm ; H NMR d
5
1
m), 1.07 (3H, s), 1.05 (3H, s), 0.34 (9H, s); C NMR d
was obtained from 36 (74.4 mg, 2.02£10 mmol) as
2
colorless needles: mp 119–120 8C (hexane–Et O); IR
2
1734, 1709, 1612 cm2 ; H NMR d 3.78 (3H, s), 3.72
(3H, s), 3.65 (1H, dd, J¼2.3, 14 Hz), 2.87–2.63 (3H, m),
2.53 (1H, ddd, J¼3.0, 5.6, 14 Hz), 2.20–2.02 (2H, m), 1.96
1
1
2
1 1
.35 (1H, s), 3.34–3.20 (1H, m), 2.66 (1H, dd, J¼6.6,
1
3
7 Hz), 2.09 (3H, s), 2.10–1.98 (2H, m), 1.16–1.11 (1H,
(1H, dd, J¼4.0, 14 Hz), 1.38–1.16 (1H, m); C NMR d
1
3
201.9, 179.7, 170.9, 169.8, 102.0, 56.4, 53.2, 52.8, 42.9,
39.1, 37.4, 31.0, 30.5; MS m/z 378 (M , 58.6). Anal. Calcd
þ
for C H IO : C, 41.29 H, 4.00. Found: C, 41.15; H, 3.99.
2
2
13.8, 188.4, 170.0, 141.3, 78.0, 44.5, 44.2, 43.9, 43.6, 29.4,
þ
3.5, 20.8, 21.5; FABMS m/z 327 (M þ1, 8.3).
1
3
15
5
FABHRMS calcd for C H GeO 327.1015, Found
1
5
25
3
3
27.1006.
2.1.33. 6-(tert-Butyldimethysiloxy)oct-1-en-7-yne (38).
According to the procedure described for preparation of
21 from 4-penten-1-ol, 38 (495 mg, 54%) was obtained
from 5-hexen-1-ol (383 mg, 3.82 mmol) as a colorless oil:
p
p
2
.1.28. (5R ,8R )-8-(tert-Butyldimethylsiloxy)-2-iodo-
,7-dimethylbicyclo[3.3.0]oct-1-en-3-one (32). According
7
to the procedure described for preparation of 7 from 9,
IR 3308, 1639 cm2 ; H NMR d 5.81 (1H, ddt, J¼6.6, 9.9,
17 Hz), 5.05–4.93 (2H, m), 4.35 (1H, dt, J¼2.0, 6.3 Hz),
2.37 (1H, d, J¼2.0 Hz), 2.12–2.04 (2H, m), 1.74–1.48 (4H,
1 1
3
1
2 (3.0 mg, 58%) was obtained from 30 (5.1 mg,
2
2
21
.28£10 mmol) as a colorless oil: IR 1715, 1626 cm
;
1
13
H NMR d 4.06 (1H, s), 3.52–3.41 (1H, m), 2.93 (1H, dd,
J¼6.9, 18 Hz), 2.18–2.06 (2H, m), 1.23–1.13 (1H, m), 1.13
m), 0.90 (9H, s), 0.13 (3H, s), 0.11 (3H, s); C NMR d
138.5, 114.6, 85.5, 72.0, 62.6, 37.9, 33.3, 25.7, 24.3, 18.2,
24.6, 25.1; FABMS m/z 239 (M þ1, 1.5). FABHRMS
þ
calcd for C H OSi 239.1831, Found 239.1829.
(
3H, s), 0.89 (9H, s), 0.84 (3H, s), 0.17 (3H, s), 0.10 (3H, s);
C NMR d 205.0, 190.6, 94.3, 79.1, 44.6, 43.1, 43.0, 42.4,
8.4, 25.7, 23.8, 18.1, 24.0, 24.8; FABMS m/z 407
1
3
1
4 27
2
þ
07.0903, Found 407.0903.
(
4
M þ1, 54.2). FABHRMS calcd for C H IO Si
2.1.34. 6-(tert-Butyldimethysiloxy)-8-(trimethylgermyl)-
oct-1-en-7-yne (39). According to the procedure described
for preparation of 8 from 3, 39 (147 mg, 93%) was obtained
1
6
28
2
p
.1.29. (5R ,8R )-8-Acetoxy-2-iodo-7,7-dimethylbi-
p
21
2
from 38 (107 mg, 4.47£10 mmol) as a colorless oil: IR
2166, 1639 cm2 ; H NMR d 5.81 (1H, ddt, J¼6.6, 10,
17 Hz), 5.05–4.93 (2H, m), 4.33 (1H, t, J¼6.6 Hz), 2.11–
2.03 (2H, m), 1.72–1.45 (4H, m), 0.90 (9H, s), 0.33 (9H, s),
1 1
cyclo[3.3.0]oct-1-en-3-one (33). According to the pro-
cedure described for preparation of 7 from 9, 33 (13.7 mg,
56%) was obtained from 31 (23.7 mg, 7.29£10 mmol) as
a colorless oil: IR 1740, 1720, 1634 cm ; H NMR d 5.33
2
2
2
1
1
13
0.13 (3H, s), 0.11 (3H, s); C NMR d 138.7, 114.5, 106.6,
88.4, 63.3, 38.1, 33.3, 25.8, 24.6, 18.3, 20.3, 24.4, 24.9;
(
(
(
1H, s), 3.42–3.32 (1H, m), 2.96–2.88 (1H, m), 2.24–2.05
2H, m), 2.13 (3H, s), 1.26–1.10 (1H, m), 1.13 (3H, s), 1.10
3H, s); C NMR d 204.0, 185.9, 169.9, 97.9, 78.6, 44.4,
þ
þ
C H GeOSi 355.1669, Found 355.1679.
FABMS m/z 355 (M þ1, 0.9). FABHRMS calcd for
1
3
1
7 35
44.3, 44.0, 41.4, 28.8, 23.1, 20.6; MS m/z 334 (M , 21.0).
HRMS calcd for C H IO 334.0066, Found 334.0062.
p
p
2.1.35. (2R ,6R )-2-(tert-Butyldimethylsiloxy)-9-(tri-
methylgermyl)bicyclo[4.3.0]non-1(9)-en-8-one (40).
1
2
15
3
2
2
.1.30. Dimethyl 2-(3-buten-1-yl)-2-[3-(trimethylgermyl)-
-propyn-1-yl]malonate (35). According to the procedure
According to the procedure described for preparation of 9
from 8, 40 (705 mg, 95%) was obtained from 39 (692 mg,
1.95 mmol) as a colorless oil: IR 1680, 1599 cm2 ; H
NMR d 4.89 (1H, t, J¼2.6 Hz), 3.16–3.07 (1H, m), 2.49
(1H, d, J¼6.6, 19 Hz), 2.17–2.11 (1H, m), 2.02–1.84 (3H,
m), 1.53–1.40 (2H, m), 1.26–1.08 (1H, m), 0.89 (9H, s),
1
1
described for preparation of 8 from 3, 35 (273 mg, 80%) was
obtained from 34 (234 mg, 1.04 mmol) as a colorless oil: IR
2
1
2
2
1 1
174, 1732, 1641 cm ; H NMR d 5.78 (1H, ddt, J¼9.9,
7, 6.3 Hz), 5.10–4.30 (2H, m), 3.72 (6H, s), 2.85 (2H, s),
.20–1.88 (4H, m), 0.30 (9H, s); C C NMR d 170.6,
1
3
13
13
0.36 (9H, s), 0.09 (3H, s), 0.01 (3H, s); C NMR d 213.0,

2506
C. Mukai et al. / Tetrahedron 60 (2004) 2497–2507
1
2
89.5, 138.6, 66.9, 42.1, 38.9, 36.6, 35.7, 25.6, 19.1, 17.9,
0.7, 24.6, 24.7; FABMS m/z 385 (M þ1, 9.3).
2.1.40. 3,3-Bis(methoxycarbonyl)-9-[2-(trimethylsilyl)-
þ
FABHRMS calcd for C H GeO Si 385.1618, Found
propyn-1-yl]bicyclo[4.3.0]non-1(9)-en-8-one (45). Accor-
ding to the procedure described for preparation of 10 from
7, 45 (26.6 mg, 99%) was obtained from 37 (29.1 mg,
1
8
35
2
3
85.1624.
2
2
7
.70£10 mmol) as a colorless oil: IR 2160, 1732, 1713,
p
.1.36. (2R ,6R )-2-Hydroxy-9-(trimethylgermyl)bi-
p
21 1
2
1624 cm ; H NMR d 3.77 (3H, s), 3.77 (1H, dd, J¼2.3,
cyclo[4.3.0]non-1(9)-en-8-one (41). According to the
procedure described for preparation of 24 from 23, 41
14 Hz), 3.71 (3H, s), 2.72–2.47 (4H, m), 2.22–1.83
(3H, m), 1.43–1.23 (1H, m), 0.22 (9H, s); C NMR d
203.6, 179.9, 171.3, 169.7, 125.2, 103.6, 94.0, 56.6, 53.2,
1
3
(
74.6 mg, 87%) was obtained from 40 (122 mg, 3.18£
21 1
21
þ
79.2). HRMS calcd for C H O Si 348.1393, Found
348.1395.
1 mmol) as colorless needles: mp 88–90 8C (hexane–
Et O); IR 3420, 1682, 1597 cm ; H NMR d 4.91 (1H,
0
52.7, 41.1, 39.4, 34.6, 30.9, 30.8, 20.1; MS m/z 348 (M ,
2
18 24 5
t, J¼2.6 Hz), 3.15–3.05 (1H, m), 2.52 (1H, dd, J¼6.6,
1
9 Hz), 2.19–1.85 (6H, m), 1.64–1.49 (1H, m), 1.33–0.88
1
3
(
4
1H, m), 0.36 (9H, s); C NMR d 212.9, 187.9, 139.4, 66.1,
2.3, 38.9, 35.6, 34.4, 19.1, 20.6; FABMS m/z: 271
2.1.41. 9-(1-Ethoxy-ethen-1-yl)-3,3-bis(methoxycarbo-
nyl)bicyclo[4.3.0]non-1(9)-en-8-one (46). According to
the procedure described for preparation of 11 from 7,
46 (22.9 mg, 87%) was obtained from 37 (30.9 mg,
þ
.50. Found: C, 53.49; H, 7.70.
(
7
M þ1, 27.8). Anal. Calcd for C H GeO : C, 53.60; H,
1
2
20
2
2
2
8
.17£10 mm) as a colorless oil: IR 1732, 1707, 1686,
p
.1.37. (2R ,6R )-2-(tert-Butyldimethylsiloxy)bi-
p
21 1
2
1616 cm ; H NMR d 4.10 (1H, dd, J¼2.3, 15 Hz), 3.79–
3.66 (2H, m), 3.73 (3H, s), 3.66 (3H, s), 2.73–2.39 (8H, m),
2.31–2.16 (1H, m), 2.11–1.98 (2H, m), 1.41–1.18 (2H, m);
cyclo[4.3.0]non-1(9)-en-8-one (42). According to the
procedure described for preparation of 9 from 8, 42
1
3
(
81.0 mg, 71%) and its epimer (6.6 mg, 6%) were obtained
2
C NMR d 203.8, 197.4, 183.2, 170.9, 170.1, 139.4, 56.6,
53.0, 52.7, 41.6, 39.6, 34.0, 30.5, 30.4, 30.3; MS m/z 322
1
from 38 (102 mg, 4.27£10 mmol). Compound 42 was a
2
1
1
þ
322.1417.
colorless oil: IR 1703, 1628 cm ; H NMR d 5.82 (1H, d,
J¼1.3 Hz), 4.73 (1H, t, J¼2.3 Hz), 3.11–3.01 (1H, m), 2.57
(M , 15.4). HRMS calcd for C H O 322.1416, Found
17 22 6
(
m), 1.59–1.42 (2H, m), 1.14–0.98 (1H, m), 0.88 (9H, s),
1H, dd, J¼6.6, 19 Hz), 2.21–2.10 (1H, m), 2.04–1.86 (3H,
2.1.42. 3,3-Bis(methoxycarbonyl)-9-phenylbicyclo[4.3.0]-
non-1(9)-en-8-one (47). According to the procedure
described for preparation of 12 from 7, 47 (22.7 mg, 88%)
1
3
0
6
.07 (3H, s), 0.00 (3H, s); C NMR d 209.3, 183.8, 125.6,
6.7, 42.1, 37.4, 35.4, 35.3, 25.6, 19.1, 18.0, 24.9, 25.1;
þ
22
MS m/z 266 (M , 3.8). Anal. Calcd for C H O Si:
1
C, 67.61 H, 9.84. Found: C, 67.27; H, 10.13. Epimer of
4
6
2
1
was obtained from 37 (29.7 mg, 7.85£10 mmol) as
5 26 2
colorless needles: mp 114–115 8C (hexane–Et O); IR
2
2 was a colorless oil: IR 1699, 1624 cm2 ; H NMR d
.07 (1H, s), 4.38–4.31 (1H, m), 2.75–2.56 (2H, m),
.17–2.01 (3H, m), 1.88–1.81 (1H, m), 1.53–1.42 (2H, m),
1
1
1732, 1697, 1645 cm ; H NMR d7.45–7.24 (5H, m),
3.72 (3H, s), 3.67 (1H, dd, J¼2.3, 14 Hz), 3.53 (3H, s),
2.80–2.49 (4H, m), 2.28–1.95 (3H, m), 1.52–1.25 (1H, m);
21
1
1
3
13
.14–1.02 (1H, m), 0.91 (9H, s), 0.08 (9H, s); C NMR
C NMR d 205.8, 171.4, 171.1, 170.1, 140.2, 131.0, 128.9,
128.2, 127.8, 56.2, 53.0, 52.4, 41.4, 39.0, 33.5, 30.8, 30.3;
d 208.0, 186.8, 125.4, 71.6, 42.3, 40.8, 36.9, 34.4, 25.7,
2
þ
for C H O Si: C, 67.61 H, 9.84. Found: C, 67.37; H,
þ
328.1311, Found 328.1315.
3.4, 18.2, 24.8, 25.0; MS m/z 266 (M , 2.6). Anal. Calcd
MS m/z 328 (M , 38.6). HRMS calcd for C H O
20
1
9
5
1
5
26
2
1
0.16.
2.1.43. 3,3-Bis(methoxycarbonyl)bicyclo[4.3.0]non-1(9)-
en-8-one (48). According to the procedure described for
p
p
2
.1.38. (2R ,6R )-2-(tert-Butyldimethylsiloxy)-9-iodo-
1
9
bicyclo[4.3.0]non-1(9)-en-8-one (43). According to the
procedure described for preparation of 7 from 9, 43
preparation of 5 from 7, 48 (19.7 mg, 87%) was obtained
2
2
from 37 (33.9 mg, 8.96£10 mmol).
(
151 mg, 95%) was obtained from 40 (155 mg, 4.05£
21
21 1
1
0
mmol) as a colorless oil: IR 1703, 1609 cm ; H
NMR d 4.83 (1H, t, J¼2.3 Hz), 3.24–3.14 (1H, m), 2.74
1H, dd, J¼6.6, 19 Hz), 2.15–1.92 (4H, m), 1.62–1.42 (2H,
m), 1.25–0.98 (1H, m), 0.89 (9H, s), 0.14 (3H, s), 0.04 (3H,
(
References and notes
1
3
s); C NMR d 203.0, 184.4, 97.0, 69.0, 40.5, 39.4, 35.9,
3
1. For leading reviews, see: (a) Pauson, P. L. In Organometallics
in organic synthesis. Aspects of a modern interdisciplinary
field. de Meijere, A., tom Dieck, H., Eds.; Springer: Berlin,
1988; p 233. (b) Schore, N. E. Chem. Rev. 1988, 88, 1081.
þ
Anal. Calcd for C H IO Si: C, 45.92 H, 6.42. Found: C,
5.0, 25.7, 19.3, 17.9, 24.3, 24.8; MS m/z 392 (M , 0.7).
1
5
25
2
4
5.94; H, 6.59.
(
c) Schore, N. E. Org. React. 1991, 40, 1. (d) Schore, N. E.
p
p
2
.1.39. (2R ,6R )-2-Hydroxy-9-iodobicyclo[4.3.0]non-
(9)-en-8-one (44). According to the procedure described
Comprehensive organic synthesis, Trost, B. M., Ed.;
Pergamon: Oxford, 1991; Vol. 5, p 1037. (e) Schore, N. E.
Comprehensive organometallic chemistry II, Abel, E. W.,
Stone, F. G. A., Wilkinson, G., Eds.; Elsevier: New York,
1995; Vol. 12, p 703. (f) Fr u¨ half, H.-W. Chem. Rev. 1997, 97,
523. (g) Jeong, N. Transition metals in organic synthesis,
Beller, H., Bolm, C., Eds.; Wiley-VCH: Weinheim, 1998; Vol.
1, p 560. (h) Geis, O.; Schmalz, H.-G. Angew. Chem., Int. Ed.
Engl. 1998, 37, 911. (i) Ingate, S. T.; Marco-Contelles, J. Org.
Prep. Proced. Int. 1998, 30, 123. (j) Chung, Y. K. Coord.
1
for preparation of 7 from 9, 44 (19.2 mg, 83%) was obtained
2
2
from 41 (22.3 mg, 8.29£10 mmol) as a colorless oil: IR
2
1 1
3
3
412, 1709, 1607 cm ; H NMR d 4.95–4.90 (1H, m),
.31–3.18 (1H, m), 2.77 (1H, dd, J¼6.6, 19 Hz), 2.18–1.90
1
3
(
d 202.9, 183.1, 98.7, 68.4, 40.5, 39.4, 35.3, 33.7, 19.4; MS
5H, m), 1.71–1.52 (2H, m), 1.26–1.02 (1H, m); C NMR
þ
Found 277.9807.
m/z 278 (M , 35.9). HRMS calcd for C H IO 277.9804,
2
9
11

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2507
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3. (a) Krafft, M. E.; Bo n˜ aga, L. V. R. Synlett 2000, 959. (b) Krafft,
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5
6
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1
6. The hydroxyl derivative derived from 27 afforded an
intractable mixture when treated with NIS under the standard
conditions.
7
. (a) Johnson, C. R.; Adams, J. P.; Braun, M. P.; Senanayake,
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9
3839.
0. Part of this work was published as a preliminary communi-
1