Rh(I)-catalyzed Pauson-Khand reaction of 1-phenylsulfonyl-1,2-octadien-7-yne derivatives

Article abstract of DOI:10.1016/j.tet.2007.04.005

The Rh(I)-catalyzed PKR of 1-phenylsulfonyl-1,2-octadien-7-ynes and their aza derivatives exclusively produced the corresponding 9-phenylsulfonylbicyclo[4.3.0]nona-1,6-dien-8-ones and no 4-(phenylsulfonylmethylidene)bicyclo[3.3.0]oct-1-en-3-ones could be

Full text of DOI:10.1016/j.tet.2007.04.005

Tetrahedron 63 (2007) 5154–5160
Rh(I)-catalyzed Pauson–Khand reaction of 1-phenylsulfonyl-
1,2-octadien-7-yne derivatives
*
Fuyuhiko Inagaki, Takamasa Kawamura and Chisato Mukai
Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University,
Kakuma-machi, Kanazawa 920-1192, Japan
Received 16 March 2007; revised 2 April 2007; accepted 2 April 2007
Available online 6 April 2007
Abstract—The Rh(I)-catalyzed PKR of 1-phenylsulfonyl-1,2-octadien-7-ynes and their aza derivatives exclusively produced the correspond-
ing 9-phenylsulfonylbicyclo[4.3.0]nona-1,6-dien-8-ones and no 4-(phenylsulfonylmethylidene)bicyclo[3.3.0]oct-1-en-3-ones could be de-
tected. Thus, the ring-closing pattern was found to be the same as those of the previously reported 3-phenylsulfonyl-1,2-octadien-7-yne
derivatives. However, the formation of 4-(phenylsulfonylmethylidene)-7-oxabicyclo[3.3.0]oct-1-en-3-ones was observed as a minor product
when the 5-oxa congeners were used. In addition, a larger ring-sized product, 10-phenylsulfonyl-5-azabicyclo[5.3.0]deca-1,7-dien-9-one
derivative, was obtained from the 6-aza derivative of 1-phenylsulfonyl-1,2-nonadien-8-yne.
Ó 2007 Elsevier Ltd. All rights reserved.
1. Introduction
regioisomers of 1 regarding the position of the phenylsul-
fonyl group on the allenyl moiety, in order to obtain infor-
mation on the effect of the phenylsulfonyl group on the
regioselectivity.
In our previous studies,1 we developed an effective method
for the construction of the bicyclo[m.3.0] ring system
(m¼4, 5, 6) based on the Rh(I)-catalyzed Pauson–Khand
reaction (PKR)2 of allenynes in which the distal double
bond of the allenyl moiety consistently took part in the
ring-closing process.1,3 Thus, a solution of 3-phenylsul-
fonyl-1,2-octadien-7-yne derivatives 1 (n¼1) was heated in
the presence of a catalytic amount of [RhCl(CO)2]2 or
[RhCl(CO)dppp]2 in toluene under CO pressure to produce
the corresponding 2-phenylsulfonylbicyclo[4.3.0]nona-1,6-
dien-8-ones 2 (n¼1) in high to reasonable yields (Scheme 1).
This ring-closing reaction could be applied to the construc-
tion of 2-phenylsulfonylbicyclo[5.3.0]deca-1,7-dien-9-ones
as well as 2-phenylsulfonylbicyclo[6.3.0]undeca-1,8-dien-
10-ones. In this study, we investigated the Rh(I)-catalyzed
PKR of 1-phenylsulfonyl-1,2-octadien-7-yne derivatives,
2. Results and discussion
The allenynes 4 were chosen as the first starting materials
for the Rh(I)-catalyzed PKR and were prepared as follows
(Scheme 2). Successive exposure of the known 3a,1bb4 to
benzenesulfenyl chloride (PhSCl) and m-chloroperbenzoic
acid (mCPBA) produced the 1-phenylsulfonyl derivatives
4a,b in 79 and 55% yields, respectively. The Sonogashira
reaction of 4b with iodobenzene furnished the phenylacetyl-
ene derivative 4c in a rather low yield (30%).
R
1) PhSCl, Et3N
THF, -78 °C
R
PhO2S
2) mCPBA, 0 °C
R1
•
R3
H
[RhCl(CO)2]2 or
CH2Cl2
R3
PhO2S
R2
HO
[RhCl(CO)dppp]2
3a: R = TMS
3b: R = H
4a: R = TMS (79%)
4b: R = H (55%)
4c: R = Ph (30%)
n
O
toluene, CO
a
PhO2S
n
R2
R1
i
Scheme 2. Reagents and conditions: (a) PhI, Pd(PPh3)2Cl2, CuI, Pr2NH,
THF, rt.
1
2
Scheme 1.
With the required allenynes 4 in hand, compound 4a was
first used for the ring-closing reaction in the presence of
a catalytic amount of [RhCl(CO)dppp]2 (2.5 mol %) in
refluxing toluene for 3 h under an atmosphere of CO,
that had been employed for the preparation of 2-
Keywords: Rh(I)-catalyzed Pauson–Khand reaction; 1-Phenylsulfonylalle-
nyne; Bicyclo[4.3.0]; Distal double bond; Proximal double bond;
[RhCl(CO)2]2.
* Corresponding author. Tel.: +81 76 234 4411; fax: +81 76 234 4410;
e-mail: cmukai@kenroku.kanazawa-u.ac.jp
0040–4020/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2007.04.005

F. Inagaki et al. / Tetrahedron 63 (2007) 5154–5160
Table 1. Rh(I)-catalyzed ring-closing reaction of compounds 4
5155
Hc
Hd
R
SO2Ph
PhO2S
Ha
SO2Ph
Hb
•
+
O
R
R
4
5
7
SO2Ph
a: R = TMS
b: R = H
c: R = Ph
O
A: [RhCl(CO)dppp]2, B: [RhCl(CO)2]2
C : Co2(CO)8, D : Mo(CO)6
a
b
6
R
Entry
s.m.
R
Rh (mol %)
CO (atm)
Solv.
Temp.
Time (h)
Product (%)
1
2
3
4
5
6
7
8
4a
4a
4a
4a
4a
4a
4a
4a
4b
4c
4b
4c
TMS
TMS
TMS
TMS
TMS
TMS
TMS
TMS
H
A (2.5)
B (2.5)
B (2.5)
B (5)
B (2.5)
B (2.5)
C (30)
D (120)
B (2.5)
B (2.5)
B (2.5)
B (2.5)
1
1
1
1
5
1
1
1
1
1
1
1
Toluene
Toluene
Xylene
Xylene
Xylene
Mesitylene
Xylene
Xylene
Xylene
Xylene
Toluene
Toluene
Reflux
Reflux
Reflux
Reflux
150 ꢀC
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
Reflux
3
18
2
1
2
1
1
2
2
5a (11)+7a (78)
5a (45)
5a (73)
5a (72)
5a (73)
5a (63)
5a (35)
5a (18)
5b (23)
5c (30)
9
10
11
12
Ph
H
Ph
2
2
1
5b (30)
5c (40)
a
Tetramethylthiourea (TMTU) of 30 mol % was used together.
DMSO (10 equiv) was used together.
b
phenylsulfonylbicyclo[4.3.0]nona-1,6-dien-8-ones 2 (n¼1),
to afford the bicyclo[4.3.0] derivative 5a in 11% yield (Table 1,
entry 1). The [RhCl(CO)dppp]2-catalyzed isomerization
of the allenyl moiety to the 1,3-diene functionality became
the major pathway giving rise to the formation of compound
7.5 No formation of the corresponding bicyclo[3.3.0] deriv-
ative 6a could be detected. Changing the Rh(I) catalyst from
[RhCl(CO)dppp]2 to [RhCl(CO)2]2 brought about a signifi-
cant improvement in the chemical yield of 5a (45%, entry
2). Again, compound 6a could not be detected. Under other-
wise identical conditions, but in refluxing xylene, the yield
of 5a was markedly increased to 73% (entry 3). When the
ring-closing reaction was carried out in the presence of
5 mol % of [RhCl(CO)2]2 in refluxing xylene, compound
5a was obtained in a similar yield (72%, entry 4). Neither
increasing the CO pressure (5 atm, heated at 150 ꢀC) nor
a higher reaction temperature (1 atm of CO in refluxing me-
sitylene) produced a further improvement in the chemical
yield (entries 5 and 6). Two other catalysts, Co2(CO)86 and
Mo(CO)6,7 were examined resulting in chemical yields
much lower than 73% (entries 7 and 8). The best conditions
for the preparation of 5a (entry 3) were then applied to other
allenynes 4b,c, but lower yields (23 and 30%) were recorded
(entries 9 and 10). Interestingly, higher yields (30 and 42%)
were obtained when 4b,c were refluxed in toluene (entries 11
and 12), which are in sharp contrast to the case of 4a (entries
2 and 3). We had tentatively anticipated the preferential
formation of the bicyclo[3.3.0] frameworks 6 over the bicy-
clo[4.3.0]ones because the phenylsulfonyl group at the C1-
position of 4 would decrease the electron density of the distal
double bond of the allenyl moiety, thereby the proximal dou-
ble bond might participate in the ring-closing process. In
contrast to our prediction, the PKR of 4 exclusively produced
the 9-phenylsulfonylbicyclo[4.3.0] products 5, although the
chemical yields were significantly lower than those of 2-
phenylsulfonylbicyclo[4.3.0] derivatives 2 (n¼1).1
Our endeavors then turned to the application of this Rh(I)-
catalyzed PKR for the allenynes 12, 15, and 16 possessing
a hetero atom on the carbon appendage. Thus, protection
of the propargyl alcohol of 88 with dihydropyran (DHP)
was followed by treatment with tetrabutylammonium fluo-
ride (TBAF) to afford 9a, which was subsequently reacted
with the tosylamide derivative 109 under the Mitsunobu con-
ditions to give 11a in 41% overall yield after removal of THP
group. According to a similar procedure, the one-carbon
homologated compound 11b was prepared in a 50% overall
yield starting from the known 9b.10 Transformation of 11a,b
into the 1-phenylsulfonylallenynes 12a,b was realized by the
standard method (PhSCl and mCPBA).1 In addition, the
oxygen congeners 15 and 16 were synthesized from 9a by
the conventional means as shown in Scheme 3.11,12
TMS
TsHN
TMS
a,b
10
c,d
NTs
HO
THPO
HO
n
n
OH
n
OTBS
8
9a: n=1
11a: n=1
11b: n=2
9b: n=2
g,h
e,f
R
R
TMS
PhO2S
PhO2S
e,f
•
•
O
O
NTs
HO
n
15: R=Ph
13: R=Ph
12a: n=1
12b: n=2
n
n
16: R= Bu
14: R= Bu
Scheme 3. Reagentsandconditions:(a)DHP, PPTS, CH2Cl2, 0 ꢀC;(b)TBAF,
THF, rt; (c) 10, DIAD, PPh3, THF, rt; (d) p-TsOH, MeOH, rt, 11a (41% from
8), 11b (50% from 9b); (e) PhSCl, Et3N, THF, ꢁ78 ꢀC: (f) mCPBA, CH2Cl2,
0 ꢀC, 12a (80%), 12b (56%), 15 (75%), 16 (77%); (g) 3-iodo-1-phenylprop-
1-yne, NaH, DMF, 0 ꢀC, then p-TsOH, MeOH, rt, 13 (70%); (h) 1-iodohept-
2-yne, NaH, DMF, 0 ꢀC, then p-TsOH, MeOH, rt, 14 (80%).

5156
F. Inagaki et al. / Tetrahedron 63 (2007) 5154–5160
Table 2. Rh(I)-catalyzed ring-closing reaction of compounds 12a, 15,
and 16
triple bond (Scheme 4). The proximal double bond was
again inactive under the Rh(I)-catalyzed PKR conditions.
PhO2S
R
SO2Ph
PhO2S
2.5 mol %
[RhCl(CO)2]2
TMS
+
O
•
O
X
SO2Ph
PhO2S
X
xylene, CO
X
2.5 mol % [RhCl(CO)2]2
R
R
•
O
1 atm of CO, 4 h
xylene, reflux, 35%
12a: R = TMS, X=NTs
15: R = Ph, X=O
17a: R = TMS, X=NTs 18a: R = TMS, X=NTs
NTs
TsN
n
TMS
17b: R = Ph, X=O
18b: R = Ph, X=O
n
n
n
16: R = Bu, X=O
17c: R = Bu, X=O
18c: R = Bu, X=O
12b: n=2
Scheme 4.
19
Entry s.m. R
X
CO (atm) Temp. Time (h) Product (%)
1
2
3
4
5
12a TMS NTs
1
1
10
1
Reflux 2
Reflux 3
150 ꢀC 2
Reflux 2
150 ꢀC 2
17a (61)
17b (45)
17b (44)+18b (17)
17c (26)+18c (19)
17c (42)+18c (7)
15 Ph
15 Ph
16 nBu
16 nBu
O
O
O
O
3. Conclusions
10
In summary, we have studied the Rh(I)-catalyzed PKR of the
1-phenylsulfonylallenynes. 1-Phenylsulfonyl-1,2-octadien-
7-yne and its analogs possessing a substituent at the alkyne
terminus exclusively afforded the corresponding 9-phenyl-
sulfonylbicyclo[4.3.0]nona-1,6-dien-8-ones. The ring-clos-
ing pattern was found to be the same as that of the
previously reported 3-phenylsulfonyl-1,2-octadien-7-yne
derivatives. Similarly, the 5-aza derivative of 1-phenylsul-
fonyl-1,2-octadien-7-yne provided the corresponding bi-
cyclo[4.3.0] compound. However, the 5-oxa congeners
produced the a-alkylidene-7-oxabicyclo[3.3.0]oct-1-en-3-
one derivatives as a minor product. In addition, 10-phenyl-
sulfonylbicyclo[5.3.0] framework could also be prepared.
A solution of the aza derivative 12a and 2.5 mol % of
[RhCl(CO)2]2 in xylene was refluxed for 2 h to produce
the cyclized product 17a in 61% yield (Table 2, entry 1).
The oxa compound 15 having a terminal phenyl group af-
forded the corresponding bicyclo[4.3.0] derivative 17b in
45% yield (entry 2). These two results are in good agreement
with those of Table 1. However, upon exposure to the condi-
tions with 10 atm of CO at 150 ꢀC for 2 h, 15 produced 17b
in 44% yield accompanied by the production of a new prod-
uct, the bicyclo[3.3.0]octenone derivative 18b13 in 17%
yield (entry 3). The butyl congener 16 also provided the bi-
cyclo[3.3.0] skeleton 18c in a low yield (19%) under the
standard conditions (entry 4). Contrary to the prediction
based on entries 2 and 3, increasing the CO pressure for com-
pound 16 did not improve the ratio of the bicyclo[3.3.0]
compound 18c to the bicyclo[4.3.0] one 17c (entry 5).
4. Experimental
4.1. General
Melting points are uncorrected. Infrared spectra were mea-
sured in CHCl3. H NMR spectra were taken in chloro-
1
It has been reported that the PKR of 1,2-octadien-7-yne de-
rivatives mediated by Mo(CO)6 consistently affords a-alkyl-
idenebicyclo[3.3.0]oct-1-en-3-ones (e.g., 18),7 in which the
proximal double bond of the allenyl moiety is incorporated
into the cyclopentenone frameworks. On the other hand, the
distal double bond of the allenyl moiety of 1,2-octadien-
7-yne derivatives exclusively takes part in the ring-closing
process under the Rh(I)-catalyzed conditions14 to provide
the bicyclo [4.3.0]nona-1,6-dien-7-ones like 17a.1,3 This
propensity was recently rationalized by calculations15 in
terms of the difference in the transition state structure of
the product-determining step (the oxidative addition of the
metal to the alkyne–allene functionalities), in which the mo-
lybdenacycles would have a distorted trigonal bipyramidal
geometry, whereas the rhodacycles would have the distorted
square planar one. In line with the conclusion based on the
calculations,15 our results in Tables 1 and 2 strongly indicate
that the [RhCl(CO)2]2-catalyzed PKR of allenynes exclu-
sively or predominantly occurs between the distal double
bond and the triple bond irrespective of the position of the
phenylsulfonyl group.
form-d (CDCl3). CHCl3 (7.26 ppm) for silyl compounds
and tetramethylsilane (0.00 ppm) for compounds without
a silyl group were used as internal standard. 13C NMR spec-
tra were recorded in CDCl3 with CDCl3 (77.0 ppm) as an
internal standard. All reactions were carried out under N2 at-
mosphere unless otherwise stated. Silica gel (Silica gel 60,
40–50 mm) was used for chromatography. Organic extracts
were dried over anhydrous Na2SO4.
4.2. General procedure for preparation of allenyl
sulfones
To a solution of propargyl alcohol in THF (0.1 M) were
added successively Et3N (3.0 equiv) and PhSCl (1.5 equiv)
at ꢁ78 ꢀC. The reaction mixture was stirred until complete
disappearance of the starting material (monitored by TLC).
The reaction mixture was quenched by addition of water and
extracted with AcOEt. The extract was washed with water
and brine, dried, and concentrated to dryness. The residual
oil was passed through a short pad of silica gel with hexane–
AcOEt to afford the crude sulfoxide. mCPBA (1.5 equiv)
was added to a solution of the crude sulfoxide in CH2Cl2
(0.1 M) at 0 ꢀC. The reaction mixture was stirred until com-
plete disappearance of the starting material (monitored by
TLC). The reaction mixture was quenched by addition of
saturated aqueous Na2S2O3 and saturated aqueous NaHCO3,
and extracted with CH2Cl2. The extract was washed with
The final subject in this investigation was the Rh(I)-cata-
lyzed PKR of the 1-phenylsulfonyl derivative 12b. Treat-
ment of 12b under the standard conditions (1 atm of CO in
refluxing xylene) for 4 h afforded the seven-membered com-
pound 19 in 35% yield, which resulted from the reaction be-
tween the distal double bond of the allenyl moiety and a

F. Inagaki et al. / Tetrahedron 63 (2007) 5154–5160
5157
water and brine, dried, and concentrated to dryness. The
residual oil was chromatographed with hexane–AcOEt to
afford allenyl sulfones. Chemical yields are summarized in
tables.
J¼6.1, 2.7 Hz), 5.87 (q, 1H, J¼6.1 Hz), 4.13 (s, 2H), 3.28
(t, 2H, J¼7.3 Hz), 2.48–2.44 (m, 2H), 2.42 (s, 3H), 0.00
(s, 9H); 13C NMR d: 205.8, 143.6, 141.2, 135.6, 133.5,
129.6, 129.2, 127.7, 127.6, 101.7, 97.6, 97.5, 91.3, 45.3,
37.8, 26.6, 21.5, ꢁ0.49; MS m/z: 487 (M+, 5.7); HRMS calcd
for C24H29O4NSiS2: 487.1307, found: 487.1327; Anal.
Calcd for C24H29NO4S2Si: C, 59.10; H, 5.99; N, 2.87.
Found: C, 58.79; H, 5.99; N, 2.76.
4.2.1. 1-(Phenylsulfonyl)-8-(trimethylsilyl)octa-1,2-dien-
7-yne (4a). A colorless oil; IR: 2172, 1958, 1321,
1
1148 cmꢁ1; H NMR d: 7.85–7.83 (m, 2H), 7.58–7.54 (m,
1H), 7.49–7.46 (m, 2H), 6.16 (dt, 1H, J¼6.1, 2.9 Hz), 5.80
(q, 1H, J¼6.1 Hz), 2.20–2.14 (m, 4H), 1.53 (quin, 2H,
J¼7.1 Hz), 0.08 (s, 9H); 13C NMR d: 205.4, 141.0, 133.2,
129.0, 127.3, 105.9, 101.2, 100.2, 85.1, 26.9, 26.4, 18.9,
ꢁ0.1; MS m/z: 318 (M+, 1.6); HRMS calcd for
C17H22O2SSi: 318.1110, found: 318.1100.
4.2.6. 1-(Phenylsulfonyl)-4-(3-phenyl-2-propynyloxy)-
buta-1,2-diene (15). A brown oil; IR: 1961, 1310,
1
1150 cmꢁ1; H NMR d: 7.95–7.93 (m, 2H), 7.61–7.57 (m,
1H), 7.51–7.48 (m, 2H), 7.45–7.43 (m, 2H), 7.34–7.31 (m,
3H), 6.32 (dt, 1H, J¼6.1, 2.7 Hz), 5.96 (q, 1H, J¼6.1 Hz),
4.42 (s, 2H), 4.29 (dd, 2H, J¼6.1, 2.7 Hz); 13C NMR d:
205.7, 141.1, 133.5, 131.8, 129.2, 128.6, 128.3, 127.7, 122.3,
102.3, 98.0, 86.9, 84.2, 65.1, 58.1; MS m/z: 324 (M+, 15);
HRMS calcd for C19H16O3S: 324.0820, found: 324.0827.
4.2.2. 1-(Phenylsulfonyl)octa-1,2-dien-7-yne (4b). A col-
orless oil; IR: 3308, 2866, 1958, 1321, 1150 cmꢁ1 1H
;
NMR d: 7.93–7.91 (m, 2H), 7.64–7.61 (m, 1H), 7.56–7.53
(m, 2H), 6.21 (dt, 1H, J¼5.8, 2.9 Hz), 5.86 (q, 1H,
J¼7.0 Hz), 2.29–2.22 (m, 4H), 1.96 (t, 1H, J¼2.5 Hz),
1.66–1.60 (m, 2H); 13C NMR d: 205.4, 141.0, 133.3,
129.0, 127.3, 101.2, 100.1, 83.2, 69.0, 26.7, 26.2, 17.4;
MS m/z: 246 (M+, 2.2); HRMS calcd for C14H14O2S:
246.0715, found: 246.0720.
4.2.7. 1-[4-(Phenylsulfonyl)-2,3-butadienyloxy]-2-hep-
1
tyne (16). A colorless oil; IR: 1961, 1310, 1150 cmꢁ1; H
NMR d: 7.92–7.91 (m, 2H), 7.63–7.60 (m, 1H), 7.55–7.52
(m, 2H), 6.28 (dt, 1H, J¼6.1, 3.1 Hz), 5.91 (q, 1H,
J¼6.1 Hz), 4.17 (dd, 2H, J¼6.1, 3.1 Hz), 4.13 (t, 2H,
J¼2.4 Hz), 2.20 (tt, 2H, J¼7.3, 2.4 Hz), 1.50–1.45 (m,
2H), 1.42–1.35 (m, 2H), 0.89 (t, 3H, J¼7.3 Hz); 13C NMR
d: 205.6, 141.0, 133.5, 129.1, 127.6, 102.1, 98.1, 87.8, 75.0,
64.7, 57.9, 30.5, 21.8, 18.3, 13.5; MS m/z: 304 (M+, 0.1);
HRMS calcd for C17H20O3S: 304.1133, found: 304.1120.
4.2.3. 8-Phenyl-1-(phenylsulfonyl)-octa-1,2-dien-7-yne
(4c). To a solution of 4b (250 mg, 1.0 mmol) in THF (10 mL)
were successively added CuI (3.8 mg, 2.0ꢂ10ꢁ2 mmol),
Pd(PPh3)2Cl2 (7.0 mg, 1.0ꢂ10ꢁ2 mmol), and iodobenzene
(0.22 mL, 2.0 mmol). After being stirred for 5 min at room
temperature, iPr2NH (1.4 mL, 10 mmol) was added, and the
mixture was further stirred for 10 h. The precipitates were
filtered off and the filtrate was concentrated to leave a resi-
dual oil, which was chromatographed with hexane–AcOEt
(2:1) to afford 4c (97 mg, 30%) as a yellow oil. IR: 2864,
4.3. Preparation of propargyl alcohol derivatives
4.3.1. N-(2-Hydroxy-3-butynyl)-N-[3-(trimethylsilyl)-2-
propynyl]-(4-methylbenzene)sulfonamide (11a). To a so-
lution of 88 (1.15 g, 5.76 mmol) in CH2Cl2 (14 mL) were
added PPTS (150 mg, 0.60 mmol) and DHP (1.6 mL,
17 mmol) at room temperature. After being stirred for
10 h, the mixture was concentrated to leave the residual
oil, which was passed through a short pad of silica gel
with hexane–AcOEt (9:1) to afford the crude acetal. TBAF
(1.0 M in THF, 6 mL, 6 mmol) was added to a solution of
the crude acetal in THF (6 mL) at room temperature. After
being stirred for 1 h, the reaction mixture was quenched by
addition of saturated aqueous NH4Cl and extracted with
AcOEt. The extract was washed with water and brine, dried,
and concentrated to dryness. The residual oil was chromato-
graphed with hexane–AcOEt (3:1) to afford 9a (970 mg) as
a pale yellow oil. DIAD (0.30 mL, 1.4 mmol) was gradually
added to a solution of 9a (220 mg, 1.3 mmol), PPh3
(370 mg), and 109 (280 mg, 1.0 mmol) in THF (7 mL) at
0 ꢀC. After being stirred for 24 h at room temperature, the re-
action mixture was concentrated to leave the residual oil,
which was passed through a short pad of silica gel with hex-
ane–AcOEt (5:1) to afford the crude diyne. p-TsOH (20 mg,
0.10 mmol) was added to a solution of the crude diyne in
MeOH (10 mL) at room temperature. After being stirred
for 12 h, the reaction mixture was concentrated to leave
the residual oil, which was chromatographed with hexane–
AcOEt (3:1) to afford 11a (146 mg, 41% for four steps) as a
1
1958, 1321, 1148 cmꢁ1; H NMR d: 7.93–7.90 (m, 2H),
7.62–7.46 (m, 3H), 7.41–7.36 (m, 2H), 7.29–7.26 (m, 3H),
6.23 (dt, 1H, J¼6.0, 3.0 Hz), 5.89 (dt, 1H, J¼6.0, 6.9 Hz),
2.46 (t, 2H, J¼6.9 Hz), 2.33 (dq, 2H, J¼3.0, 6.9 Hz), 1.70
(quin, 2H, J¼6.9 Hz); 13C NMR d: 205.7, 141.2, 133.4,
131.5, 129.1, 128.7, 128.2, 127.6, 123.7, 101.4, 100.4,
88.9, 81.4, 27.2, 26.7, 18.6; MS m/z: 322 (M+, 10.9);
HRMS calcd for C20H18O2S: 322.1028, found: 322.1023.
4.2.4. N-[4-(Phenylsulfonyl)buta-2,3-dienyl]-N-[3-(tri-
methylsilyl)propyn-2-yl]-(4-methylbenzene)sulfonamide
(12a). Colorless needles; mp 110.5–111 ꢀC (AcOEt); IR:
1
2177, 1961, 1308, 1151 cmꢁ1; H NMR d: 7.93–7.91 (m,
2H), 7.73–7.55 (m, 5H), 7.30 (d, 2H, J¼7.9 Hz), 6.27 (dt,
1H, J¼6.1, 2.4 Hz), 5.83 (q, 1H, J¼6.1 Hz), 4.17 (AB-q,
2H, J¼18.3 Hz), 3.98 (AB-qdd, 2H, J¼14.9, 6.1, 2.4 Hz),
2.42 (s, 3H), 0.00 (s, 9H); 13C NMR d: 206.0, 143.8,
140.8, 135.8, 133.7, 129.7, 129.3, 127.7, 102.6, 97.4, 96.6,
91.6, 44.1, 37.4, 21.5, ꢁ0.47; MS m/z: 473 (M+, 20);
HRMS calcd for C23H27O4NSiS2: 473.1151, found:
473.1165; Anal. Calcd for C23H27NO4S2Si: C, 58.32; H,
5.75; N, 2.96. Found: C, 58.07; H, 5.73; N, 2.96.
4.2.5. N-[5-(Phenylsulfonyl)penta-3,4-dienyl]-N-[3-(tri-
methylsilyl)propyn-2-yl]-(4-methylbenzene)sulfonamide
(12b). Colorless plates; mp 91.5–92.5 ꢀC (AcOEt); IR:
1
colorless oil. IR: 3503, 3306, 2177 cmꢁ1; H NMR d: 7.76–
7.73 (m, 2H), 7.31–7.25 (m, 2H), 4.67–4.60 (m, 1H), 4.29 (s,
2H), 3.42–3.40 (m, 2H), 2.81 (d, 1H, J¼5.4 Hz), 2.50 (d, 1H,
J¼2.1 Hz), 2.41 (s, 3H), 0.00 (s, 9H); 13C NMR d: 144.3,
1
2177, 1950, 1308, 1150 cmꢁ1; H NMR d: 7.93–7.91 (m,
2H), 7.72–7.54 (m, 5H), 7.30–7.28 (m, 2H), 6.23 (dt, 1H,

5158
F. Inagaki et al. / Tetrahedron 63 (2007) 5154–5160
136.0, 130.1, 128.3, 98.6, 91.7, 82.6, 74.8, 61.9, 52.6, 40.3,
22.0, 0.00; MS m/z: 349 (M+, 8.1); HRMS calcd for
C17H23O3NSSi: 349.1168, found: 349.1159.
(30 mg, 9.4ꢂ10ꢁ2 mmol) in toluene (1.0 mL). The reaction
mixture was refluxed under a CO atmosphere for 3 h. Tolu-
ene was evaporated off, and the residual oil was chromato-
graphed with CH2Cl2 to afford 5a (3.5 mg, 11%) and 7a
(24 mg, 78%). 9-(Phenylsulfonyl)-7-(trimethylsilyl)bicy-
clo[4.3.0]nona-1,6-dien-8-one (5a); yellow plates; mp
4.3.2. N-(3-Hydroxy-4-pentynyl)-N-[3-(trimethylsilyl)-2-
propynyl]-(4-methylbenzene)sulfonamide (11b). Accord-
ing to the procedure for the conversion of 9a into 11a,
9b10 (156 mg, 0.85 mmol) was treated with DIAD
(0.20 mL, 1.1 mmol), PPh3 (290 mg, 1.1 mmol), and 109
(200 mg, 0.7 mmol) to give the crude diyne, which was ex-
posed to p-TsOH (70 mg, 0.36 mmol) to afford 11b
(127 mg, 50% for two steps) as a colorless oil. IR: 3524,
122–123 ꢀC (AcOEt); IR: 1695, 1321, 1144 cmꢁ1 1H
;
NMR d: 7.76–7.74 (m, 2H), 7.64–7.60 (m, 1H), 7.50–7.47
(m, 2H), 6.71 (t, 1H, J¼3.7 Hz), 4.22 (s, 1H), 2.66–2.60
(m, 1H), 2.55–2.52 (m, 1H), 2.50–2.33 (m, 2H), 1.83–1.72
(m, 2H), 0.10 (s, 9H); 13C NMR d: 197.3, 177.3, 137.6,
136.7, 133.8, 133.7, 132.0, 129.4, 128.4, 69.0, 27.1, 25.3,
21.5, ꢁ1.0; MS m/z: 346 (M+, 8.8); HRMS calcd for
C18H22O3SSi: 346.1059, found 346.1068; Anal. Calcd for
C18H22O3SSi: C, 62.39; H, 6.40. Found: C, 62.04; H, 6.41.
(1Z,3E)-1-(Phenylsulfonyl)-8-(trimethylsilyl)octa-1,3-dien-
3308, 2177 cmꢁ1
;
1H NMR d: 7.69 (d, 2H, J¼8.3 Hz),
7.25 (d, 2H, J¼8.3 Hz), 4.55 (br s, 1H), 4.18 (d, 1H,
J¼18.8 Hz), 4.03 (d, 1H, J¼18.8 Hz), 3.44 (ddd, 1H,
J¼14.3, 8.2, 6.3 Hz), 3.22 (ddd, 1H, J¼13.7, 6.3, 5.1 Hz),
2.92 (s, 1H), 2.45 (d, 1H, J¼2.2 Hz), 2.38 (s, 3H), 2.02–
1.87 (m, 2H), ꢁ0.04 (s, 9H); 13C NMR d: 143.5, 135.4,
129.5, 127.7, 97.8, 91.1, 84.1, 73.0, 59.0, 42.5, 37.7, 35.4,
21.4, ꢁ0.5; MS m/z: 363 (M+, 1.2); HRMS calcd for
C18H25O3NSSi: 363.1325, found: 363.1320.
7-yne (7a); a colorless oil; IR: 2174, 1637, 1321, 1147 cmꢁ1
;
1H NMR d: 7.90 (d, 2H, J¼7.9 Hz), 7.60 (t, 1H, J¼7.9 Hz),
7.53 (t, 2H, J¼7.9 Hz), 7.36 (dd, 1H, J¼14.6, 11.6 Hz), 6.58
(dd, 1H, J¼11.6, 11.0 Hz), 6.15 (dt, 1H, J¼14.6, 7.3 Hz),
6.03 (d, 1H, J¼11.0 Hz), 2.46–2.43 (m, 2H), 2.36 (t, 2H,
J¼7.3 Hz), 0.14 (s, 9H); 13C NMR d: 145.6, 141.8, 141.6,
133.1, 129.1, 127.1, 125.7, 124.8, 105.5, 85.7, 32.0, 19.3,
0.0; MS m/z: 318 (M+, 1.6); HRMS calcd for C17H22O2SSi:
318.1110, found: 318.1118.
4.3.3. 1-(3-Phenyl-2-propynyloxy)-3-butyn-2-ol (13).
NaH (160 mg, 4.0 mmol, 60% in oil) was added to a solution
of 9a (340 mg, 2.0 mmol) in DMF (10 mL) at 0 ꢀC. After be-
ing stirred for 30 min, 3-iodo-1-phenylprop-1-yne (1.4 g,
5.7 mmol) was added to the mixture at 0 ꢀC. The mixture
was stirred for 2 h, quenched by addition of water and
extracted with Et2O. The extract was washed with water
and brine, dried, and concentrated to dryness. The residual
oil was passed through a short pad of silica gel with hexane–
AcOEt (5:1) to afford the crude ether. p-TsOH (16 mg,
0.10 mmol) was added to a solution of the crude ether in
MeOH (10 mL). After being stirred for 1 h, the reaction
mixture was quenched by addition of saturated aqueous
NaHCO3 and MeOH was evaporated off. The residual oil
was extracted with AcOEt, which was washed with water
and brine, dried, and concentrated to dryness. The residual
oil was chromatographed with hexane–AcOEt (5:1) to afford
4.4.2. General procedure for Pauson–Khand reaction of
allenynes with [RhCl(CO)2]2 under a CO atmosphere.
[RhCl(CO)2]2 (1.0 mg, 2.5ꢂ10ꢁ3 mmol or 2.0 mg,
5.0ꢂ10ꢁ3 mmol) was added to a solution of allenyne
(0.10 mmol) in toluene, xylene, or mesitylene (1.0 mL).
The reaction mixture was refluxed under a CO atmosphere
until the starting material completely disappeared (moni-
tored by TLC). Solvent was evaporated off and the residual
oil was chromatographed with hexane–AcOEt to afford cy-
clized products. Chemical yields are summarized in tables.
4.4.3. General procedure for Pauson–Khand reaction of
allenynes with [RhCl(CO)2]2 under 5 or 10 atm of CO.
[RhCl(CO)2]2 (1.0 mg, 2.5ꢂ10ꢁ3 mmol) was added to a so-
lution of allenyne (0.10 mmol) in xylene (1.0 mL). The reac-
tion mixture was stirred at 150 ꢀC under 5 or 10 atm of CO
until the starting material completely disappeared
(monitored by TLC). Xylene was evaporated off and the
residual oil was chromatographed with hexane–AcOEt to
afford cyclized products. Chemical yields are summarized
in tables.
13 (280 mg, 70%) as a colorless oil. IR: 3578, 3306 cmꢁ1
;
1H NMR d: 7.45–7.44 (m, 2H), 7.32–7.31 (m, 3H), 4.62–
4.61 (m, 1H), 4.48 (AB-q, 2H, J¼15.9 Hz), 3.76 (AB-qd,
2H, J¼9.7, 3.6 Hz), 2.62 (d, 1H, J¼5.5 Hz), 2.48 (d, 1H,
J¼2.4 Hz); 13C NMR d: 131.7, 128.5, 128.2, 122.2, 86.8,
84.3, 81.5, 73.8, 73.1, 61.3, 59.3; MS m/z: 200 (M+, 1.3);
HRMS calcd for C13H12O2: 200.0837, found: 200.0845.
4.3.4. 1-(2-Heptynyloxy)-3-butyn-2-ol (14). According to
the procedure for the preparation of 13 from 9a, 14
(140 mg, 80%) was obtained from 9b (170 mg, 1.0 mmol)
4.4.4. Pauson–Khand reaction of allenyne 4a with
Co2(CO)8 and TMTU. Co2(CO)8 (10 mg, 3.0ꢂ10ꢁ2 mmol)
was added to a solution of allenyne 4a (32 mg, 0.10 mmol)
and TMTU (4.0 mg, 3.0ꢂ10ꢁ2 mmol) in xylene (1.0 mL).
The reaction mixture was refluxed under a CO atmosphere
for 1 h. Xylene was evaporated off and the residual oil was
chromatographed with hexane–AcOEt (3:1) to afford 5a
(12 mg, 35%).
1
as a colorless oil. IR: 3566, 3308 cmꢁ1; H NMR d: 4.59–
4.54 (m, 1H), 4.23 (AB-qt, 2H, J¼13.2, 2.3 Hz), 3.68
(AB-qd, 2H, J¼9.6, 3.6 Hz), 2.47 (d, 1H, J¼2.1 Hz),
2.25–2.19 (m, 3H), 1.55–1.36 (m, 4H), 0.93–0.88 (m, 3H);
13C NMR d: 87.7, 81.6, 75.1, 73.6, 72.8, 61.1, 59.1, 30.5,
21.8, 18.2, 13.4; MS m/z: 180 (M+, 0.1); HRMS calcd for
C11H16O2: 180.1150, found: 180.1149.
4.4.5. Pauson–Khand reaction of allenyne 4a with
Mo(CO)6 and DMSO. Mo(CO)6 (32 mg, 0.12 mmol) was
added to a solution of allenyne 4a (32 mg, 0.10 mmol) and
DMSO (8.0ꢂ10ꢁ2 mL, 1.0 mmol) in xylene (1 mL). The
reaction mixture was refluxed under a CO atmosphere for
2 h. Xylene was evaporated off and the residual oil was
4.4. Pauson–Khand reaction of allenynes
4.4.1. Pauson–Khand reaction of allenyne 4a with
[RhCl(CO)dppp]2.
[RhCl(CO)dppp]2
(2.7 mg,
2.4ꢂ10ꢁ3 mmol) was added to a solution of allenyne 4a

F. Inagaki et al. / Tetrahedron 63 (2007) 5154–5160
5159
chromatographed with hexane–AcOEt (3:1) to afford 5a
(6.2 mg, 18%).
J¼16.6, 1.0 Hz), 4.35–4.32 (m, 1H), 3.49 (dd, 1H, J¼10.5,
8.3 Hz); 13C NMR d: 193.1, 175.0, 142.6, 139.6, 136.0,
134.4, 131.2, 129.8, 129.7, 129.5, 128.8, 128.1, 127.9,
69.4, 66.3, 46.9; MS m/z: 352 (M+, 4.1); HRMS calcd for
C20H16O4S: 352.0769, found: 352.0776.
4.4.6. 9-(Phenylsulfonyl)bicyclo[4.3.0]nona-1,6-dien-8-
1
one (5b). A yellow oil; IR: 1701, 1310, 1144 cmꢁ1; H
NMR d: 7.80–7.78 (m, 2H), 7.66–7.62 (m, 1H), 7.52–7.49
(m, 2H), 6.71 (t, 1H, J¼4.2 Hz), 5.74 (d, 1H, J¼0.7 Hz),
4.29 (s, 1H), 2.64–2.51 (m, 2H), 2.47–2.36 (m, 2H), 1.79
(quin, 2H, J¼6.3 Hz); 13C NMR d: 193.5, 171.8, 136.9,
134.7, 134.1, 130.6, 129.5, 128.7, 126.3, 68.6, 26.2, 25.6,
21.3; MS m/z: 274 (M+, 2.0); HRMS calcd for C15H14O3S:
274.0664, found: 274.0654.
4.4.12. 2-Butyl-4-[(E)-(phenylsulfonyl)methylene]-7-oxa-
bicyclo[3.3.0]oct-1-en-3-one (18c). A pale yellow oil; IR:
1
1708, 1637, 1310, 1153 cmꢁ1; H NMR d: 7.92–7.90 (m,
2H), 7.68–7.66 (m, 1H), 7.60–7.57 (m, 2H), 7.01 (d, 1H,
J¼1.8 Hz), 4.85 (t, 1H, J¼7.9 Hz), 4.64 (AB-q, 2H,
J¼15.9 Hz), 4.16–4.12 (m, 1H), 3.43 (dd, 1H, J¼10.3,
7.9 Hz), 2.40–2.34 (m, 1H), 2.24–2.18 (m, 1H), 1.48–1.26
(m, 4H), 0.87 (t, 3H, J¼7.3 Hz); 13C NMR d: 195.1,
173.6, 142.2, 139.7, 138.6, 134.3, 130.3, 129.6, 127.9,
70.0, 64.7, 46.8, 29.8, 24.3, 22.5, 13.7; MS m/z: 332 (M+,
0.1); HRMS calcd for C18H20O4S: 332.1082, found:
332.1084.
4.4.7. 7-Phenyl-9-(phenylsulfonyl)bicyclo[4.3.0]nona-
1,6-dien-8-one (5c). A yellow oil; IR: 1703, 1323,
1175 cmꢁ1 1H NMR d: 7.75–7.72 (m, 2H), 7.58–7.53
;
(m, 1H), 7.45–7.39 (m, 2H), 7.31–7.16 (m, 3H), 7.12–7.09
(m, 2H), 6.73 (t, 1H, J¼4.3 Hz), 4.36 (s, 1H), 2.72–2.49 (m,
2H), 2.41–2.39 (m, 2H), 1.71 (quin, 2H, J¼6.4 Hz); 13C
NMR d: 192.0, 165.6, 136.9, 136.3, 134.2, 134.1, 130.1,
129.7, 129.5, 128.8, 128.7, 128.22, 128.17, 68.7, 25.74,
25.67, 21.4; MS m/z: 350 (M+, 3.8); HRMS calcd for
C21H18O3S: 350.0977, found: 350.0975.
4.4.13. N-[4-(Methylbenzene)sulfonyl]-10-(phenylsul-
fonyl)-8-(trimethylsilyl)-5-azabicyclo[5.3.0]deca-1,7-
dien-9-one (19). A brown oil; IR: 1697, 1308, 1161 cmꢁ1
;
1H NMR d: 7.74–7.72 (m, 2H), 7.66–7.52 (m, 5H), 7.32–
7.30 (m, 2H), 6.51 (t, 1H, J¼5.1 Hz), 4.42 (d, 1H,
J¼17.8 Hz), 4.16–4.01 (m, 2H), 3.56–3.46 (m, 2H), 2.80–
2.74 (m, 2H), 2.43 (s, 3H), 0.16 (s, 9H); 13C NMR d:
196.9, 174.4, 143.9, 143.4, 136.4, 135.8, 134.2, 133.8,
131.6, 129.9, 129.4, 128.9, 126.9, 72.5, 50.7, 48.4, 32.2,
21.5, ꢁ0.8; MS m/z: 515 (M+, 74.6); HRMS calcd for
C25H29O5NS2Si: 515.1257, found: 515.1265.
4.4.8. N-[4-(Methylbenzene)sulfonyl]-9-(phenylsulfonyl)-
7-(trimethylsilyl)-4-azabicyclo[4.3.0]nona-1,6-dien-8-
one (17a). A pale yellow oil; IR: 1699, 1310, 1165 cmꢁ1; 1H
NMR d: 7.72 (d, 2H, J¼8.3 Hz), 7.65–7.62 (m, 3H), 7.52–
7.49 (m, 2H), 7.31 (d, 2H, J¼8.3 Hz), 6.53–6.52 (m, 1H),
4.45 (d, 1H, J¼16.8 Hz), 4.15 (dd, 1H, J¼18.8, 4.4 Hz),
4.11 (s, 1H), 4.00–3.92 (m, 2H), 2.42 (s, 3H), 0.15 (s, 9H);
13C NMR d: 196.6, 168.6, 144.4, 139.5, 136.7, 134.3,
133.5, 130.8, 129.9, 129.4, 128.9, 127.6, 126.7, 68.2, 44.9,
44.6, 21.5, ꢁ1.3; MS m/z: 501 (M+, 17); HRMS calcd for
C24H27O5NS2Si: 501.1100, found: 501.1099.
Acknowledgements
This work was supported in part by a Grant-in Aid for Sci-
entific Research from the Ministry of Education, Culture,
Sports, Science and Technology, Japan, for which we are
grateful.
4.4.9. 7-Phenyl-9-(phenylsulfonyl)-4-oxabicyclo[4.3.0]-
nona-1,6-dien-8-one (17b). A pale yellow oil; IR: 1711,
1
1325, 1155 cmꢁ1; H NMR d: 7.85–7.33 (m, 8H), 7.16–
7.12 (m, 2H), 6.81 (t, 1H, J¼3.3 Hz), 4.72 (AB-q, 2H,
J¼16.3 Hz), 4.51–4.48 (m, 3H); 13C NMR d: 191.4, 159.7,
136.7, 134.4, 134.3, 130.6, 129.5, 129.2, 128.8, 128.5,
127.2, 68.1, 65.1, 63.8; MS m/z: 352 (M+, 2.4); HRMS calcd
for C20H16O4S: 352.0769, found: 352.0766.
References and notes
1. (a) Mukai, C.; Nomura, I.; Yamanishi, K.; Hanaoka, M. Org.
Lett. 2002, 4, 1755–1758; (b) Mukai, C.; Nomura, I.;
Kitagaki, S. J. Org. Chem. 2003, 68, 1376–1385; (c) Mukai,
C.; Inagaki, F.; Yoshida, T.; Kitagaki, S. Tetrahedron Lett.
2004, 45, 4117–4121; (d) Mukai, C.; Inagaki, F.; Yoshida, T.;
Yoshitani, K.; Hara, Y.; Kitagaki, S. J. Org. Chem. 2005, 70,
7159–7171; (e) Mukai, C.; Hirose, T.; Teramoto, S.;
Kitagaki, S. Tetrahedron 2005, 61, 10983–10994.
2. For leading reviews of the PKR, see: (a) Pauson, P. L.
Organometallics in Organic Synthesis. Aspects of a Modern
Interdisciplinary Field; de Meijere, A., Tom Dieck, H., Eds.;
Springer: Berlin, 1988; pp 233–246; (b) Schore, N. E. Chem.
Rev. 1988, 88, 1081–1119; (c) Schore, N. E. Org. React.
1991, 40, 1–90; (d) Schore, N. E. Comprehensive Organic
Synthesis; Trost, B. M., Ed.; Pergamon: Oxford, 1991; Vol. 5,
pp 1037–1064; (e) Schore, N. E. Comprehensive Organo-
metallic Chemistry II; Abel, E. W., Stone, F. G. A.,
Wilkinson, G., Eds.; Elsevier: New York, NY, 1995; Vol. 12,
pp 703–739; (f) Fr€uhauf, H.-W. Chem. Rev. 1997, 97, 523–
596; (g) Jeong, N. Transition Metals in Organic Synthesis;
Beller, H., Bolm, C., Eds.; Wiley-VCH: Weinheim, 1998;
4.4.10. 7-Butyl-9-(phenylsulfonyl)-4-oxabicyclo[4.3.0]-
nona-1,6-dien-8-one (17c). Colorless plates; 156–
1
157.5 ꢀC (AcOEt); IR: 1709, 1622, 1310, 1150 cmꢁ1; H
NMR d: 7.82–7.80 (m, 2H), 7.67–7.64 (m, 1H), 7.54–7.51
(m, 2H), 6.64 (t, 1H, J¼3.1 Hz), 4.62 (d, 1H, J¼16.5 Hz),
4.49 (d, 1H, J¼16.5 Hz), 4.42–4.41 (m, 2H), 4.35 (s, 1H),
2.17–2.11 (m, 1H), 2.03–1.98 (m, 1H), 1.26–1.05 (m, 4H),
0.82 (t, 3H, J¼6.7 Hz); 13C NMR d: 193.0, 159.8, 137.2,
136.8, 134.2, 129.4, 128.8, 128.5, 127.3, 67.5, 64.9, 63.1,
29.8, 22.7, 22.3, 13.7; MS m/z: 332 (M+, 0.2); HRMS calcd
for C18H20O4S: 332.1082, found: 332.1093.
4.4.11. 2-Phenyl-4-[(E)-(phenylsulfonyl)methylene]-7-
oxabicyclo[3.3.0]oct-1-en-3-one (18b). A pale yellow oil;
IR: 1719, 1325, 1153 cmꢁ1 1H NMR d: 7.96–7.94 (m,
;
2H), 7.72–7.69 (m, 1H), 7.62–7.59 (m, 2H), 7.56–7.54 (m,
2H), 7.46–7.40 (m, 3H), 7.14 (d, 1H, J¼2.0 Hz), 5.05 (dd,
1H, J¼16.6, 1.5 Hz), 4.95 (t, 1H, J¼8.3 Hz), 4.66 (dd, 1H,

5160
F. Inagaki et al. / Tetrahedron 63 (2007) 5154–5160
Vol. 1, pp 560–577; (h) Geis, O.; Schmalz, H.-G. Angew.
Tetrahedron Lett. 1998, 39, 931–934; (c) Brummond, K. M.;
Wan, H.; Kent, J. L. J. Org. Chem. 1998, 63, 6535–6545; (d)
Brummond, K. L.; Kerekes, A. D.; Wan, H. J. Org. Chem.
2002, 67, 5156–5163.
Chem., Int. Ed. 1998, 37, 911–914; (i) Chung, Y. K. Coord.
Chem. Rev. 1999, 188, 297–341; (j) Brummond, K. M.; Kent,
J. L. Tetrahedron 2000, 56, 3263–3283; (k) Bon˜aga, L. V. R.;
Krafft, M. E. Tetrahedron 2004, 60, 9795–9833.
8. Trost, B. M.; Fandrick, D. R.; Dinh, D. C. J. Am. Chem. Soc.
2005, 127, 14186–14187.
9. Trost, B. M.; Machacek, M. R.; Faulk, B. D. J. Am. Chem. Soc.
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ꢀ
10. Nazare, M.; Waldmann, H. Chem.—Eur. J. 2001, 7, 3363–
3376.
11. Both 3-iodo-1-phenylprop-1-yne ( Richard, C. L.; Chow, M.-S.
Tetrahedron Lett. 1984, 25, 2727–2728 ) and 1-iodohept-2-yne
(Homsi, F.; Rousseau, G. Tetrahedron Lett. 1999, 40, 1495–
1498) are known compounds.
12. We have tried to prepare the 5-oxa congener of 4a in order to
compare its reactivity with those of the allenynes 4a and 12a,
both of which have a trimethylsilyl group at the triple bond
terminus. However, the Williamson ether synthesis of 9a with
3-iodo-1-trimethylsilylprop-1-yne did not produce the corre-
sponding ether derivative except for the formation of the
desilylated product.
13. The stereochemistry of compound 18 was determined to be (E)
by comparison of the NMR spectral data with those of the com-
pounds obtained by the Mo(CO)6-mediated PKR, see Ref. 7.
14. Two examples for the low-yield formation of the a-alkylidene-
bicyclo[3.3.0]oct-1-en-3-one skeleton by the Rh(I)-catalyzed
PKR were reported, see Refs. 3c,e.
3. Rh(I)-catalyzed PKR of allenynes: (a) Kobayashi, T.; Koga, Y.;
Narasaka, K. J. Organomet. Chem. 2001, 624, 73–87; (b)
Brummond, K. M.; Chen, H.; Fisher, K. D.; Kerekes, A. D.;
Rickards, B.; Sill, P. C.; Geib, S. J. Org. Lett. 2002, 4, 1931–
1934; (c) Shibata, T.; Kadowaki, S.; Hirase, M.; Takagi, K.
Synlett 2003, 573–575; (d) Brummond, K. M.; Gao, D. Org.
Lett. 2003, 5, 3491–3494; (e) Brummond, K. M.; Mitasev, B.
Org. Lett. 2004, 6, 2245–2248.
4. Chiristoph, B.; Reinhart, K. Helv. Chim. Acta 1996, 79, 2164–
2171.
5. The stereochemistry of compound 7 was established based on
NMR considerations. The coupling constant between Ha and
Hb revealed a typical value (14.6 Hz) for the trans relationship,
while the coupling constant of Hc with Hd was 11.0 Hz. In order
to confirm the relation between Hc and Hd, an NOE experiment
was performed. Irradiation of Hc showed a 12.6% enhancement
of Hd as well as a 12.0% enhancement of Ha, thereby the
cis relationship between Hc and Hd could be unambiguously
confirmed.
6. (a) Tang, Y.; Deng, L.; Zhang, Y.; Dong, G.; Chen, J.; Yang, Z.
Org. Lett. 2005, 7, 593–595; (b) Mukai, C.; Yoshida, T.;
Sorimachi, M.; Odani, A. Org. Lett. 2006, 8, 83–86.
7. (a) Kent, J. L.; Wan, H.; Brummond, K. M. Tetrahedron Lett.
1995, 36, 2407–2410; (b) Brummond, K. M.; Wan, H.
15. Bayden, A.S.;Brummond,K.M.;Jordan, K.D.Organometallics
2006, 25, 5204–5206.