Rh(I)-catalyzed Pauson-Khand reaction and cycloisomerization of allenynes: Selective preparation of monocyclic, bicyclo[m.3.0], and bicyclo[5.2.0] ring systems

Article abstract of DOI:10.1021/jo050770z

Rhodium(I)-catalyzed PKR of allenynes was found to be applicable for constructing azabicyclo[5.3.0]decadienone as well as oxabicyclo[5.3.0] decadienone frameworks. In addition, a reliable procedure for constructing a 10-monosubstituted bicyclo[5.3.0]deca-

Full text of DOI:10.1021/jo050770z

Rh(I)-Catalyzed Pauson-Khand Reaction and Cycloisomerization
of Allenynes: Selective Preparation of Monocyclic, Bicyclo[m.3.0],
and Bicyclo[5.2.0] Ring Systems
Chisato Mukai,* Fuyuhiko Inagaki, Tatsunori Yoshida, Katsuya Yoshitani,
Yasuyuki Hara, and Shinji Kitagaki
Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology,
Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
cmukai@kenroku.kanazawa-u.ac.jp
Received April 15, 2005
Rhodium(I)-catalyzed PKR of allenynes was found to be applicable for constructing azabicyclo-
[5.3.0]decadienone as well as oxabicyclo[5.3.0]decadienone frameworks. In addition, a reliable
procedure for constructing a 10-monosubstituted bicyclo[5.3.0]deca-1,7-dien-9-one ring system by
the rhodium(I)-catalyzed PKR of allenynes was developed under the condition of 10 atm of CO.
Investigation of the rhodium(I)-catalyzed cycloisomerization of 4-phenylsulfonylnona-2,3-dien-8-
ynes under nitrogen atmosphere gave the corresponding cyclohexene derivatives, whereas the C1-
homologated allenynes produced cycloheptene derivatives and/or bicyclo[5.2.0]nonene skeletons
depending on the substitution pattern at the allenic terminus. Thus, proper choice of the starting
allenynes and reaction conditions led to the selective formation of 2-phenylsulfonylbicyclo[5.3.0]-
deca-1,7-dien-9-ones (Pauson-Khand-type product), 3-alkylidene-1-phenylsulfonyl-2-vinylcyclo-
heptene derivatives, and bicyclo[5.2.0]nonene frameworks.
Introduction
bicyclo[m.3.0] skeletons (m ) 3, 4) in one operation.
However, this attractive ring-closing method generally
is not effective for the synthesis of bicyclo[5.3.0]decenones2,3
in large part due to entropic as well as enthalpic factors
which could impede the formation of larger rings.4 In the
previous papers,5 we developed a new and efficient
procedure for the construction of the bicyclo[5.3.0]-
decadienone framework 2 (R3 ) R4 ) H) based on the
Rh(I)-catalyzed intramolecular PKR of 1,1-disubstituted
The Co2(CO)8-mediated Pauson-Khand reaction (PKR)1
is well recognized as a formal [2 + 2 + 1] cyclization of
three components, an alkyne, an alkene, and carbon
monoxide, on the two cobalt atoms of the cluster complex
to produce cyclopentenone derivatives. The intramolecu-
lar version of this intriguing [2 + 2 + 1] cyclization
procedure has emerged as one of the most convenient and
straightforward methods for the construction of the
* To whom correspondence should be addressed. Tel: +81-76-234-
4411. Fax: +81-76-234-4410.
(2) For attempts at constructing the bicyclo[5.3.0]decenone skeleton
via the intramolecular PKR of enynes, see: (a) Wender, P. A.;
McDonald, F. E. Tetrahedron Lett. 1990, 31, 3691-3694. (b) Mukai,
C.; Sonobe, H.; Kim, J. S.; Hanaoka, M. J. Org. Chem. 2000, 65, 6654-
6659.
(3) For construction of seven and larger-membered rings via PKR
of enynes with an aromatic ring as a template, see: (a) Pe´rez-Serrano,
L.; Casarrubios, L.; Dom´ınguez, G.; Pe´rez-Castells, J. Chem. Commun.
2001, 2602-2603. (b) Krafft, M. E.; Fu, Z.; Bon˜aga, L. V. R. Tetrahe-
dron Lett. 2001, 42, 1427-1431. (c) Lovely, C. J.; Seshadri, H.;
Wayland, B. R.; Cordes, A. W. Org. Lett. 2001, 3, 2607-2610. (d)
Barluenga, J.; Sanz, R.; Fan˜ana´s, F. J. Chem. Eur. J. 1997, 3, 1324-
1336.
(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; 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. In Comprehensive Organic
Synthesis; Trost, B. M., Ed.; Pergamon: Oxford, 1991; Vol. 5, pp 1037-
1064. (e) Schore, N. E. In Comprehensive Organometallic Chemistry
II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Elsevier: New
York, 1995; Vol. 12, pp 703-739. (f) Fru¨hauf, H.-W. Chem. Rev. 1997,
97, 523-596. (g) Jeong, N. In Transition Metals in Organic Synthesis;
Beller, H., Bolm, C., Eds; Wiley-VCH: Weinheim, 1998; Vol. 1, pp 560-
577. (h) Geis, O.; Schmalz, H.-G. Angew. 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.
(4) Illuminati, G.; Mandolini, L. Acc. Chem. Res. 1981, 14, 95-102.
(5) (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.
10.1021/jo050770z CCC: $30.25 © 2005 American Chemical Society
Published on Web 08/02/2005
J. Org. Chem. 2005, 70, 7159-7171
7159

Mukai et al.
SCHEME 1
SCHEME 2a
allenynes 1 (R3 ) R4 ) H) possessing a phenylsulfonyl
group at the C1-position. In fact, allenynes 1 were
refluxed in toluene in the presence of a catalytic amount
6
of commercially available [RhCl(CO)2]2 or [RhCl(CO)-
dppp]2,7 prepared from commercially available [RhCl-
(cod)]2 and 1,3-bis(diphenylphosphino)propane (dppp),
under a carbon monoxide atmosphere to afford 2 as the
sole product in a moderate to high yield. This ring-closing
reaction was shown to occur selectively between the distal
double bond of the allenic moiety and the alkyne coun-
terpart of 1 (R3 ) R4 ) H), resulting in the exclusive
formation of the bicyclo[5.3.0]decadienone framework 2
(R3 ) R4 ) H) (Scheme 1).8
a Reaction conditions: (a) EtMgBr, THF, 0 °C, 4a (60%), 4d
(52%); (b) nBuLi, TMSCl, THF, -78 °C, then 10% HCl, rt, 4b
(76%), 4e (70%); (c) PhI, Pd(PPh3)2Cl2, CuI, iPr2NH, THF, rt, 4c
(85%), 4f (83%); (d) PhSCl, Et3N, THF, -78 °C; (e) m-CPBA,
CH2Cl2, 0 °C, 5a (71%); 5b (70%), 5c (93%), 5d (76%), 5e (72%),
5f (78%).
52%. Introduction of a silyl group at the triple bond
terminus of 4a and 4d was realized under conventional
conditions to furnish 4b and 4e in the respective yields
of 76% and 70%. On the other hand, the Sonogashira
coupling reaction11 of 4a and 4d with iodobenzene in the
presence of Pd(PPh3)2Cl2 provided 4c and 4f in 85 and
83% yields, respectively. Exposure of 4 to benzenesulfenyl
chloride (PhSCl)12 in THF at -78 °C in the presence of
Et3N effected successive sulfenic ester formation and the
[2,3]-sigmatropic rearrangement resulting in the forma-
tion of the sulfinyl allenynes, which were subsequently
oxidized with m-CPBA to produce 5 (Scheme 2).
Our next endeavors focused on (i) the PKR of allenynes
1 having substituents at the allenic terminus (R3 and/or
R4 ) carbon appendage) to confirm the scope and limita-
tions of this rhodium(I)-catalyzed intramolecular ring-
closing reaction, (ii) the cycloisomerization reaction of
allenynes 1 (R3 and/or R4 ) carbon appendage) for
construction of other carbon frameworks, and (iii) the
application of these reactions to the construction of
heterocycles. This paper describes the results of the above
9
three topics in detail.
With the required allenynes 5 for the ring-closing
reaction in hand, these compounds were submitted to the
rhodium(I)-catalyzed ring-closing conditions that had
been established for the preparation of bicyclo[5.3.0]deca-
1,7-dien-9-ones 1 (R3 ) R4 ) H).5 For the initial evalu-
ation of the rhodium(I)-catalyzed PKR of the allenynes
5 with substitutents at the allenic terminus, a solution
of 5a in toluene in the presence of 2.5 mol % of [RhCl-
Results and Discussion
Pauson-Khand Reaction of 4-Phenylsulfonyl-
nona-2,3-dien-8-yne Derivatives. At the beginning of
this program before considering the ring-closing reaction
of allenynes leading to construction of the 10-substituted
bicyclo[5.3.0]deca-1,7-dien-9-one frameworks, our first
efforts were preliminarily directed toward the PKR of the
4-phenylsulfonylnona-2,3-dien-8-yne derivatives, which
would hopefully give the 9-substituted bicyclo[4.3.0]nona-
1,6-dien-8-ones. Thus, the required allenynes 5 were
easily prepared from commercially available 1,6-hep-
tadiyne (3) in a straightforward manner as shown in
Scheme 2. According to the literature precedents,10
compound 3 was treated with EtMgBr in THF, and the
resulting acetylide was quenched by addition of acetal-
dehyde and acetone to afford the propargyl alcohol
derivatives 4a and 4d in the respective yields of 60% and
13
(CO)dppp]2 was refluxed under an atmosphere of CO
to give the cyclohexene derivative 7a with a crossed-
triene moiety in 95% yield together with a small amount
of the bicyclo[4.3.0]nonadienone derivative 6a (4%) (Table
1, entry 1). The formation of 7a could be rationalized in
terms of the intermediacy of the rhodacyclo intermediate
I, which would collapse to 7a via the â-hydride elimina-
tion of the methyl group at the allenic terminus,14-18
whereas 6a must be produced through a CO-insertion
step from the common intermediate I. This was not the
case for the rhodacyclo intermediate, derived from 1,1-
disubstituted allenynes (e.g., 1, R3 ) R4 ) H),5,6 where
no â-hydrogens existed. Trisubstituted allene 5c with a
(6) Brummond and co-workers have reported the [RhCl(CO)2]2-
catalyzed PKR of allenynes, which involves three successful examples
of the formation of the bicyclo[5.3.0]decadienone skeleton: 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.
(7) Sanger, A. R. J. Chem. Soc., Dalton Trans. 1977, 120-129.
(8) For other examples of the formation of the bicyclo[5.3.0]decane
skeleton via transition metal-catalyzed PKR of allenynes, see: (a)
Shibata, T.; Koga, Y.; Narasaka, K. Bull. Chem. Soc. Jpn. 1995, 68,
911-919. (b) Ahmar, M.; Locatelli, C.; Colombier, D.; Cazes, B.
Tetrahedron Lett. 1997, 38, 5281-5284.
(9) Part of this work was published as a preliminary communica-
tion: Mukai, C.; Inagaki, F.; Yoshida, T.; Kitagaki, S. Tetrahedron Lett.
2004, 45, 4117-4121.
(10) (a) Trost, B. M.; Romero, D. L.; Rise, F. J. Am. Chem. Soc. 1994,
116, 4268-4278. (b) Willis, M. S. B.; Danheiser, R. L. J. Am. Chem.
Soc. 1998, 120, 9378-9379.
(11) Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron Lett.
1975, 16, 4467-4470.
(12) Horner, L.; Binder, V. Liebigs Ann. Chem. 1972, 757, 33-68.
(13) [RhCl(CO)dppp]2 was first used in PKR by Jenog and co-
workers, see: (a) Jeong, N.; Lee, S.; Sung, B. K. Organometallics 1998,
17, 3642-3644. (b) Jeong, N.; Sung, B. K.; Choi, Y. K. J. Am. Chem.
Soc. 2000, 122, 6771-6772.
(14) For reviews on cycloisomerization of enynes, see: (a) Trost, B.
M. Acc. Chem. Res. 1990, 23, 34-42. (b) Aubert, C.; Buisine, O.;
Malacria, M. Chem. Rev. 2002, 102, 813-834.
(15) For Rh(I)-catalyzed enyne cycloisomerization, see: Cao, P.;
Wang, B.; Zhang, X. J. Am. Chem. Soc. 2000, 122, 6490-6491.
(16) For Rh(I)-catalyzed allenene cycloisomerization, see: (a) Maki-
no, T.; Itoh, K. Tetrahedron Lett. 2003, 44, 6335-6338. (b) Makino,
T.; Itoh, K. J. Org. Chem. 2004, 69, 395-405.
7160 J. Org. Chem., Vol. 70, No. 18, 2005

Rh(I)-Catalyzed Pauson-Khand Reaction of Allenynes
TABLE 1. Rh(I)-Catalyzed Ring-Closing Reaction of Compounds 5 under an Atmosphere of CO
entry
substrate
R1
R2
catalyst
time (h)
product and yield (%)
1
2
5a
5b
5c
5a
5b
5c
5d
5e
5f
H
H
TMS
Ph
[RhCl(CO)dppp]2
[RhCl(CO)dppp]2
[RhCl(CO)dppp]2
[RhCl(CO)2]2
0.5
7
12
0.2
0.2
0.2
6
12
12
2
6a (4)
6b (62)
6c (8)
6a (59)
6b (55)
6c (2)
7a (95)
7b (29)
7c (63)
7a (30)
7b (43)
7c (61)
7d (21)
7e (29)
7f (83)
7d (66)
7e (71)
7f (60)
H
3
H
4
H
H
TMS
Ph
H
TMS
Ph
H
TMS
Ph
5
H
[RhCl(CO)2]2
6
H
[RhCl(CO)2]2
7
Me
Me
Me
Me
Me
Me
[RhCl(CO)dppp]2
[RhCl(CO)dppp]2
[RhCl(CO)dppp]2
[RhCl(CO)2]2
8
6e (48)
9
10
11
12
5d
5e
5f
[RhCl(CO)2]2
[RhCl(CO)2]2
2
5
6e (26)
phenyl group at the triple bond terminus behaved
similarly to 5a (entry 3). In contrast to these compounds,
5b provided the Pauson-Khand-type product 6b as a
major product (62%) along with 7b (29%) (entry 2).
Changing a rhodium(I) catalyst from [RhCl(CO)dppp]2
to [RhCl(CO)2]219 brought about some improvement in the
PKR of 5a, resulting in the formation of the bicyclo[4.3.0]
derivative 6a in 59% yield as a major product (entry 4).
However, no significant improvement in the chemical
yield of 6b and 6c was realized when [RhCl(CO)2]2 was
used in the PKR of 5b and 5c (entries 5 and 6).20 The
tetrasubstituted allenes 5d-f were found not to be
suitable substrates for rhodium(I)-catalyzed PKR. Thus,
allenes 5d and 5f exclusively produced the corresponding
cyclohexene deriviatives 7d and 7f irrespective of the
rhodium(I) catalyst (entries 7, 9, 10, and 12). The
behavior of allene 5e with a terminal TMS group was
different from those of 5d and 5f. Compound 5e provided
the Pauson-Khand-type product 6e in 48% yield as a
major product upon exposure to [RhCl(CO)dppp]2 (entry
8).21 The ring-closing reaction of 5e in the presence of
[RhCl(CO)2]2 also gave 6e in 26% yield, although the
predominant production of cyclohexene derivative 7e was
observed in 71% yield (entry 11). The stereochemistry of
the exo-methylene moiety of cyclohexene derivatives 7
was unambiguously determined to be (E) on the basis of
1H NMR spectral considerations. For example, 13 and
15% enhancement of vinyl protons was recorded when
Ha in 7b was irradiated in an NOE experiment. An NOE
experiment with 7f revealed a 7% enhancement between
Ha and R1 (Me).
We envisaged that increasing the CO pressure in the
ring-closing reaction of 5 would facilitate the CO insertion
process resulting in the preferential production of the
bicyclo[4.3.0]nonadienone skeleton 6 over the â-hydride
elimination product 7. To search for what atm of CO
pressure was efficient for acceleration of the CO insertion
process, the ring-closing reaction of 5e under several CO
pressures was investigated because 5e was the only
tetrasubstituted allene which produced the Pauson-
Khand-type product 6e (Table 1, entries 8 and 11). Thus,
a solution of compound 5e in toluene was heated at 120
°C in the presence of 2.5 mol % of [RhCl(CO)2]2 under 5
atm of CO for 4 h to furnish predominantly the desired
6e in 84% yield along with 7e in 10% yield (Table 2, entry
2). The selective formation of 6e was realized by increas-
ing the CO pressure. Further increasing the CO pressure
from 5 to 10 atm produced 6e in the highest chemical
yield (93%) (entry 3). A pressure higher than 10 atm of
CO was found to be ineffective in comparison with 10
atm of CO. In fact, a slightly lowered chemical yield of
(17) During this ongoing study, a similar Rh(I)-catalyzed allenyne
cycloisomerization has been reported independently by two groups.
Brummond and co-workers have reported the [RhCl(CO)2]2-catalyzed
construction of six-membered triene derivatives: (a) Brummond, K.
M.; Chen, H.; Sill, P.; You, L. J. Am. Chem. Soc. 2002, 124, 15186-
15187. (b) Brummond, K. M.; Mitasev, B. Org. Lett. 2004, 6, 2245-
2248. An example of the preparation of seven-membered oxacycle with
triene moiety using a RhCl(PPh3)3-catalyzed reaction, developed by
Shibata and co-workers, has also been reported. Shibata, T.; Takesue,
Y.; Kadowaki, S.; Takagi, K. Synlett 2003, 268-270.
(18) For other examples of transition-metal-catalyzed allenyne
cycloisomerizations, see: (a) Pagenkopf, B. L.; Belanger, D. B.;
O’Mahony, D. J. R.; Livinghouse, T. Synthesis 2000, 1009-1019. (b)
Oh, C. H.; Jung, S. H.; Rhim, C. Y. Tetrahedron Lett. 2001, 42, 8669-
8671.
(19) [RhCl(CO)2]2 was first used in PKR by Narasaka and co-
workers, see: (a) Koga, Y.; Kobayashi, T.; Narasaka, K. Chem. Lett.
1998, 249-250. (b) Kobayashi, T.; Koga, Y.; Narasaka, K. J. Orga-
nomet. Chem. 2001, 624, 73-87.
(20) [RhCl(COD)]2 was examined for PKR of compounds 5a-c
under an atmosphere of CO gave 6a-c (21-65%) and 7a-c (25-58%).
No significant difference from [RhCl(CO)dppp]2 and [RhCl(CO)2]2 could
be observed.
(21) Compound 6e (81%) was predominantly formed along with 7e
(18%) when treated with 2.5 mol % of [RhCl(COD)]2.
J. Org. Chem, Vol. 70, No. 18, 2005 7161

Mukai et al.
SCHEME 3a
TABLE 2. Rh(I)-Catalyzed Ring-Closing Reaction of
Compounds 5e under CO Pressure
product and
yield (%)
CO pressure
(atm)
entry
catalyst
time (h)
6e
7e
1
2
3
4
5
1
5
10
20
20
[RhCl(CO)2]2
[RhCl(CO)2]2
[RhCl(CO)2]2
[RhCl(CO)2]2
[RhCl(CO)dppp]2
2
4
26
84
93
87
2
73
10
5
5
9
20
6
a Reaction conditions: (a) EtMgBr, THF, 0 °C, 9a (58%); (b)
nBuLi, TMSCl, THF, -78 °C, then 10% HCl, rt, 9b (85% from
9a), 9d (41% from 8), 9e (47% from 8), 9f (40% from 8); (c) PhI,
Pd(PPh3)2Cl2, CuI, iPr2NH, THF, rt, 9c (95%); (d) PhSCl, Et3N,
THF, -78 °C; (e) m-CPBA, CH2Cl2, 0 °C, 10a (65%), 10b (77%),
10c (67%), 10d (88%), 10e (87%), 10f (88%).
21
TABLE 3. Rh(I)-Catalyzed Ring-Closing Reaction of
Compounds 5a-d in the Presence of [RhCl(CO)2]2 under
10 atm of CO Pressure
Preparation of 10-Substituted 2-Phenylsulfonylbi-
cyclo[5.3.0]deca-1,7-dien-9-ones by Pauson-Khand
Reaction. By taking advantage of the optimized condi-
tions for the PKR of 4-phenylsulfonylnona-2,3-dien-8-
ynes 5, the formation of 10-substituted bicyclo[5.3.0]-
decadienone frameworks from trisubstituted allenes 10
was investigated. According to the procedure10 described
for the preparation of 5 from 3, commercially available
1,7-octadiyne (8) was converted into the corresponding
propargyl alcohol derivatives 9, which were then submit-
ted to [2,3]-sigmatropic rearrangement and oxidation to
provide six trisubstituted allenes 10 as depicted in
Scheme 3.
entry substrate R1
R2
time (h) product and yield (%)
1
2
3
4
5a
5b
5c
5d
H
H
0.3
0.5
0.3
6
6a (65)
6b (72)
6c (26)
7a (23)
7b (25)
7c (56)
7d (57)
H
TMS
Ph
H
Me
H
Upon exposure to the optimized conditions (2.5 mol %
of [RhCl(CO)2]2 under 10 atm of CO in toluene at 120°C),
10a predominantly produced 10-methylbicyclo[5.3.0]deca-
1,7-dien-9-one 11a, but the yield was fairly low (17%)
(Table 4, entry 1). Similar congeners possessing TMS or
a phenyl group at the triple bond terminus, 10b and 10c,
gave the corresponding bicyclic compounds 11b and 11c
in high yield in a highly selective manner (entries 2 and
3). Furthermore, exclusive construction of 10-butyl-, 10-
benzyl-, and 10-benzyloxymethylbicyclo[5.3.0]decadienone
skeletons 11d-f was realized in acceptable yield (entries
4-6). In these cases, the formation of cycloheptene
derivatives 12d-f could be completely suppressed. Com-
pounds 10a without a substituent at the triple bond
terminus furnished 11a in a low yield (entry 1). However,
11a might be prepared in an acceptable yield via the
TMS-congener 11b because the TMS group can be
regarded as a surrogate for H.23 The ring-closing reaction
of 10 under an atmosphere of CO was examined as a
control experiment (entries 7-13), where the predomi-
nant formation of cycloheptene derivatives 12 was con-
sistently observed except for the benzyl congener 10e.
1-Methyl-4-phenylsulfonyldeca-2,3-dien-9-ynes 14 (tet-
rasubstituted allenes) were prepared from 8 via diynes
13 (Scheme 4) and subsequently exposed to the best
conditions so far ([RhCl(CO)2]2 under 10 atm of CO in
toluene at 120 °C). However, Pauson-Khand-type prod-
6e (87%) was observed when the ring-closing reaction
was performed under 20 atm CO with otherwise identical
conditions (entry 4).22 [RhCl(CO)dppp]2 gave a trace
amount of 6e (2%) (entry 5).
The Pauson-Khand-type compound, [4.3.0]nonadienone
derivative 6e, was obtained in 93% yield upon exposure
of tetrasubstituted allenyne 5e to 2.5mol % of [RhCl-
(CO)2]2 under 10 atm of CO. Therefore, we next examined
application of the optimized conditions to other 4-phe-
nylsulfonylnona-2,3-dien-8-yne derivatives. The results
are presented in Table 3. As can be seen in Table 3,
preferential formation of the Pauson-Khand-type prod-
ucts 6a and 6b could be attained (entries 1 and 2),
although the selectivity was much lower than that of 5e
where the Pauson-Khand-type compound 6e was formed
in an almost exclusive manner. In the case of 5c, the
bicyclic derivative 6c was no longer a major product
(entry 3). In addition, 6d could not be isolated from the
reaction mixture (entry 4). Thus, it turned out that
increasing the CO pressure (10 atm) in the ring-closing
reaction of trisubstituted allenynes 5 favored Pauson-
Khand-type products 6 over â-elimination compounds 7,
compared with those under an atmosphere of CO. In the
cases of tetrasubstituted allenynes 5, however, the
formation of Pauson-Khand-type products 6 seemed to
be unfavorable even under 10 atm of CO except for the
case of 5e.
(22) 2.5 mol % of [RhCl(COD)]2 catalyzed PKR of 5e under 10 atm
of CO to give 6e in 87% yield along with a small amount of 7e (5%).
When 5e was treated with 2.5 mol % of [RhCl(COD)]2 under 20 atm of
CO, 6e was obtained in 81% yield along with 7e in 15% yield.
(23) (a) Utimoto, K.; Kitai, M.; Nozaki, H. Tetrahedron Lett. 1975,
2825-2828. (b) Bu¨chi, G.; Wu¨est, H. Tetrahedron Lett. 1977, 4305-
4306. (c) Miller, R. B.; Al-Hassan, M. I. J. Org. Chem. 1983, 48, 4113-
4116.
7162 J. Org. Chem., Vol. 70, No. 18, 2005

Rh(I)-Catalyzed Pauson-Khand Reaction of Allenynes
SCHEME 5a
TABLE 4. Rh(I)-Catalyzed PKR of Compounds 10 under
10 atm of CO
CO time
product and
yield (%)
entry substrate R1
R2 (atm) (h)
1
2
10a
10b
10c
10d
10e
10f
10a
10a
10b
10b
10c
10d
10e
H
H
H
H
10
TMS 10
Ph 10
3
11a (17) 12a (2)
13 11b (79) 12b (8)
3
6
11c (80) 12c (8)
4
nPr TMS 10b
13 11d (67)
12 11e (86)
5
Ph
TMS 10b
6
BnO TMS 10
6
1
11f (91)
11a (4) 12a (77)
7
H
H
H
H
H
H
H
TMS
TMS
Ph
1c
8
1c,d
1c
15 11b (7) 12a (43)
9
3
6
4
5
6
11b (19) 12b (68)
11b (37) 12b (47)
11c (14) 12c (62)
11d (24) 12d (70)e
11e (79) 12e (7)f
10
11
12
13
1c,d
1c
a Reaction conditions: (a) DEAD, PPh3, THF, 0 °C to rt; (b)
PPTS, EtOH, 55 °C, 21a (53%), 21b (37%), 21d (63%), 21e (47%),
21g (52%), 24a (92% from 18), 24b (36% from 18 via 23a); (c) PhI,
Pd(PPh3)2Cl2, CuI, iPr2NH, THF, rt, 21c (88%), 21f (85%); (d)
PhSCl, Et3N, THF, -78 °C; (e) m-CPBA, CH2Cl2, 0 °C, 22a (72%),
22b (91%), 22c (86%), 22d (81%), 22e (95%), 22f (88%), 22g (94%),
25a (82%), 25b (89%); (f) tBuOK, THF, 0 °C
nPr TMS
Ph TMS
1c
1c
a Bath temperature. b 10 mol% of [RhCl(CO)2]2 was used. c Re-
fluxed in toluene. d [RhCl(CO)dppp]2 was used instead of [RhCl-
(CO)2]2. e A mixture of (E)- and (Z)-isomers was obtained in a ratio
of 4 to 1. f A mixture of (E)- and (Z)-isomers was obtained in a
ratio of 3 to 1.
basis of these results obtained in Table 4 and Scheme 4
in combination with those in Table 3, it might be
concluded that [RhCl(CO)2]2-catalyzed the intramolecular
PKR of trisubstituted allenes under 10 atm of CO
proceeded selectively to afford the corresponding 10-
monosubstituted 2-phenylsulfonylbicyclo[5.3.0]deca-1,7-
dien-9-ones 11 in reasonable yield. However, tetrasub-
stituted allenes were shown to be generally not suitable
substrates for rhodium(I)-catalyzed PKR.
SCHEME 4a
Application of rhodium(I)-catalyzed PKR to the con-
struction of azabicyclo as well as oxabicyclo[5.3.0] ring
systems was the next subject in this investigation. To
this end, the starting allenynes were synthesized by
conventional means as depicted in Scheme 5. Condensa-
tion of N-tosylpropargylamides 1617a and 1725 with homo-
propargyl alcohols 18-2026 under the Mitsunobu condi-
tions18a gave the corresponding condensed products,
which were treated with PPTS in EtOH to afford 21. On
the other hand, the oxygen congeners 24 were prepared
from homopropargyl alcohol 18 via the Williamson ether
synthesis. The diyne derivatives 21a-g and 24a,b were
then exposed to the two-step conditions for transforma-
tion of the propargyl alcohol moiety into a phenylsulfon-
ylallene group to provide the corresponding aza-allenynes
22a-g and oxa-allenynes 25a,b, respectively.
a Reaction conditions: (a) EtMgBr, THF, 0 °C, 13a (54%); (b)
nBuLi, TMSCl,THF, -78 °C, then 10% HCl, rt, 13b (68%); (c) PhI,
Pd(PPh3)2Cl2, CuI, iPr2NH, THF, rt, 13c (92%); (d) PhSCl, Et3N,
THF, -78 °C; (e) m-CPBA, CH2Cl2, 0 °C, 14a (73%), 14b (81%),
14c (77%); (f) 2.5 mol % [RhCl(CO)2]2, toluene, CO (10 atm), 120
°C, 15a (6%), 15b (14%) [recovery of 14b (20%)], 15c (69%)
ucts could not be detected in the reaction mixture.
Production of cycloheptene frameworks 15a,b24 in low
yield was observed instead. In the case of the phenyl
congener 14c, the triene derivative 15c was formed in
good yield (69%). The formation of the triene skeleton
15 was consistent with that observed in the ring-closing
reaction of 1-methylnona-2,3-dien-8-yne derivative 5d
under 10 atm of CO pressure, where cyclohexene deriva-
tive 7d was exclusively produced (see Table 3). On the
According to the previously reported procedure for the
PKR of 1,1-disubstituted allenes,5 the N-tosylamide
derivatives 22a-c were exposed to a rhodium(I) catalyst
in refluxing toluene under an atmosphere of CO to afford
the desired azabicyclo[5.3.0]decadienone derivatives 26a-c
in high yield (Table 5, entries 1-6). Similarly, the oxygen
(25) Trost, B. M.; Toste, F. D. J. Am. Chem. Soc. 2002, 124, 5025-
5036.
(24) (E)-Stereochemistry of 15 was determined on the basis of NOE
experiments. For instance, 3.4% enhancement of vinyl protons and
1.5% enhancement of methyl group were recorded when Ha of 15c was
irradiated.
(26) (a) Landor, P. D.; Landor, S. R.; Pepper, E. S. J. Chem. Soc. C
1967, 185-189. (b) Claesson, A.; Ta¨mnefors, I.; Olsson, L. I. Tetra-
hedron Lett. 1975, 16, 1509-1512. (c) Kim, H. J.; Jang, J. Y.; Chung,
K. H.; Lee, J. H. Biosci. Biotechnol. Biochem. 1999, 63, 494-499.
J. Org. Chem, Vol. 70, No. 18, 2005 7163

Mukai et al.
TABLE 5. Rh(I)-Catalyzed Ring-Closing Reaction of
TABLE 6. Rh(I)-Catalyzed Cycloisermerization of
Compounds 5 under an Atmosphere of N2
Compounds 22a-c and 25a,b under an Atmosphere of CO
product
time
and
entry substrate
X
R
catalyst
(h) yield (%)
product
and
time
1
2
22a
22b
22c
22a
22b
22c
25a
25b
25a
25b
NTs
H
[RhCl(CO)dppp]2
1
1
1
1
1
1
1
4
2
1
26a (89)
26b (99)
26c (94)
26a (67)
26b (84)
26c (94)
27a (66)
27b (81)
27a (59)
27b (69)
entry substrate R1
R2
catalyst
(h) yield (%)
NTs TMS [RhCl(CO)dppp]2
3
NTs Ph
NTs
[RhCl(CO)dppp]2
[RhCl(CO)2]2
1
2
5a
5b
5c
5a
5b
5c
5d
5e
5f
H
H
[RhCl(CO)dppp]2
2
7a (95)
7b (74)
4
H
H
TMS [RhCl(CO)dppp]2 12
5
NTs TMS [RhCl(CO)2]2
NTs Ph
O
O
O
O
3
H
Ph
H
[RhCl(CO)dppp]2
[RhCl(CO)2]2
0.2 7c (89)
0.2 7a (70)
6
[RhCl(CO)2]2
[RhCl(CO)dppp]2
4
H
7
H
5
H
TMS [RhCl(CO)2]2
Ph
H
2
7b (73)a
8
TMS [RhCl(CO)dppp]2
6
H
[RhCl(CO)2]2
[RhCl(CO)dppp]2
0.2 7c (59)
9
H
[RhCl(CO)2]2
7
Me
3
5
7
3
5
7
7d (58)b
7e (92)
7f (78)c
7d (93)
7e (57)d,e
7f (79)f
10
TMS [RhCl(CO)2]2
8
Me TMS [RhCl(CO)dppp]2
9
Me Ph
Me
[RhCl(CO)2]2
[RhCl(CO)2]2
10
11
12
5d
5e
5f
H
SCHEME 6
Me TMS [RhCl(CO)2]2
Me Ph [RhCl(CO)2]2
a Compound 6b was obtained in 10% yield. b Compound 5d was
recovered in 4% yield. c Compound 5f was recovered in 5% yield.
d Compound 6e was obtained in 5% yield. e Compound 5e was
recovered in 17% yield. f Compound 5f was recovered in 11% yield.
a minor product along with the triene derivative 32
(46%). This behavior might be the same as that of 5e
(Table 1, entry 11). Thus, the rhodium(I)-catalyzed PKR
of not only 1,1-disubstituted but also 1,1,3-trisubstituted
allenynes can be applicable to the construction of the
corresponding azabicyclo- as well as oxabicyclo[5.3.0]-
deca-1,7-diene-9-one frameworks in reasonable yield.
Cycloisomerization of 4-Phenylsulfonylnona-2,3-
dien-8-yne and 4-Phenylsulfonyldeca-2,3-dien-9-yne
Derivatives under Nitrogen Atmosphere. In the
rhodium(I)-catalyzed PKR of 4-phenylsulfonylnona-2,3-
dien-8-yne derivatives 5 under an atmosphere of CO
(previously reported conditions),5 undesirable cyclohexene
compounds 7 with a crossed-triene moiety were isolated
as a major product. On the other hand, preferential
formation of bicyclo[4.3.0]nonadienones 6 as well as
bicyclo[5.3.0]decadienones 11 under the Pauson-Khand
conditions was realized by increasing the CO pressure
(1-10 atm). Thus, the next phase of this program
involved development of a reliable procedure for the
selective construction of 3-alkylidene-1-phenylsulfonyl-
2-vinylcyclohex-1-ene derivatives 7. A solution of trisub-
stituted allene 5a in toluene was refluxed in the presence
of 2.5 mol % of [RhCl(CO)dppp]2 under an atmosphere
of nitrogen to give 7a in 95% yield as a sole product
(Table 6, entry 1). A similar treatment of compounds 5b
and 5c afforded 7b and 7c in respective yields of 74%
and 89% (entries 2 and 3). [RhCl(CO)2]2 also worked well
to furnish the corresponding triene derivatives 7a-c
(entries 4-6).27 In the case of 5b with [RhCl(CO)2]2,
unexpected formation of bicyclo[4.3.0] derivative 6b (10%)
was recorded (entry 5). Presumably, one of two carbon
monoxide ligands on the rhodium catalyst would, in part,
congeners 25a,b produced the corresponding oxabicyclo-
[5.3.0]decadienone compounds 27a,b in good yield (en-
tries 7-10). The chemical yields in the preparation of the
azabicyclic frameworks seemed to be generally higher
than those of oxabicyclic ones. Both [RhCl(CO)dppp]2 and
[RhCl(CO)2]2 catalysts served as superior catalysts for
this ring-closing reaction under an atmosphere of CO.
In particular, the former was consistently more effective
than the latter. This result is in good accordance with
the previously observed tendency5 in the PKR of
allenynes 1 (R3 ) R4 ) H).
[RhCl(CO)dppp]2-catalyzed PKR of the tosylamide
derivative 22e with a trisubstituted-allenyl moiety was
carried out under the aforementioned conditions (10 atm
of CO in toluene at 120 °C), described for the selective
preparation of the bicyclo[5.3.0]decadienone skeleton, to
produce the desired product 28 in 86% yield (Scheme 6).
The corresponding triene compound could not be found
in more than trace quantities in the reaction mixture.
The phenyl congener 22f afforded the azabicyclic product
29 in rather lower yield (55%) along with the triene
derivative 30 in 14% yield. However, compound 22d
without a substituent at the triple bond terminus gave
an intractable mixture in which neither the azabicyclic
product nor the triene derivative could be detected. The
PKR of tetrasubstituted allenyne 22g under 10 atm of
CO was fruitless, as can be predicted based on the results
of 14 in Scheme 4. Interestingly, a similar PKR of 22g
under an atmosphere of CO provided 31 in 27% yield as
(27) [RhCl(COD)2]2 could be used for transformation of 5a-c into
7a-c in slightly lower yield [7a (69%), 7b (66%), and 7c (44%)].
7164 J. Org. Chem., Vol. 70, No. 18, 2005

Rh(I)-Catalyzed Pauson-Khand Reaction of Allenynes
TABLE 7. Rh(I)-Catalyzed Cycloisomerization of
Compounds 10 under an Atmosphere of N2
TABLE 8. Rh(I)-Catalyzed Cycloisomerization of
Compounds 22d-f under an Atmosphere of N2
product
and
product
and
(h) yield (%)
time
time
entry substrate R1
R2
catalyst
(h) yield (%)
entry substrate R1
R2
catalyst
1
2
3
4
5
6
22d
22e
22f
22d
22e
22f
H
H
H
H
H
H
H
[RhCl(CO)dppp]2
1
4
4
2
2
4
33 (97)
34 (67)
30 (48)
33 (72)
34 (91)
30 (74)
1
2
3
4
5
6
7
8
10a
10b
10c
10a
10b
10c
10d
10e
H
H
H
H
H
H
H
[RhCl(CO)dppp]2
2
6
5
6
6
9
5
5
12a (82)
12b (83)
12c (29)
12a (78)
12b (69)b
12c (65)
12d (65)c
12e (65)a
TMS [RhCl(CO)dppp]2
TMS [RhCl(CO)dppp]2
Ph
H
[RhCl(CO)dppp]2
[RhCl(CO)dppp]2
a
Ph
H
[RhCl(CO)dppp]2
[RhCl(CO)2]2
TMS [RhCl(CO)dppp]2
Ph [RhCl(CO)dppp]2
TMS [RhCl(CO)2]2
Ph [RhCl(CO)2]2
a
d
nPr TMS [RhCl(CO)2]2
Ph TMS [RhCl(CO)2]2
TABLE 9. Rh(I)-Catalyzed Cycloisomerization of
Compounds 14 under an Atmosphere of N2
a 5 mol% of catalyst was used. b The reported yield (59%) in a
preliminary communication9 was improved. c A mixture of (E)- and
(Z)-pentenyl isomers, in a ratio of 4 to 1, was obtained. The ratio
was determined by 1H NMR. d 10 mol% of catalyst was used. f A
mixture of (E)- and (Z)-trimethylsilylmethylidene isomers, in a
ratio of 3 to 5, was obtained. The ratio was determined by 1H NMR.
participate in the ring-closing reaction. Tetrasubstituted
allenes 5d-f were exposed to both catalysts under an
atmosphere of nitrogen to afford the corresponding cy-
clohexene derivatives 7d-f in acceptable yields as shown
in Table 6. [RhCl(COD)]2 was found to be a less effective
catalyst, in comparison with the above two catalysts.28
Compound 5e provided a small amount of the bicyclic
derivative 6e (5%) when treated with [RhCl(CO)2]2 (entry
11), which is in accordance with the result of entry 5.
By analogy to the selective transformation of allenes
5 into the cyclohexene derivatives 7 under an atmosphere
of nitrogen, the C1-homologated trisubstituted allenes
10a,b were exposed to 2.5 mol % of [RhCl(CO)dppp]2 in
refluxing toluene under an atmosphere of nitrogen to
afford the cychoheptene derivatives 12a,b in high yield
as expected (Table 7, entries 1 and 2). When 10c was
submitted to the ring-closing conditions with [RhCl(CO)-
dppp]2, the reaction rate was rather slow and 12c was
formed in 29% yield along with the recovery of the
starting material 10c (51%) (entry 3). [RhCl(CO)2]2
consistently produced the corresponding cycoheptene
derivatives 12a-c in reasonable yields (entries 4-6). The
other two substrates 10d,e also afforded the correspond-
ing cycloheptene derivatives 12d,e in good yields when
treated with [RhCl(CO)2]2 (entries 7 and 8).29 The nitro-
gen congeners 22d-f with a trisubstituted allenyl moiety
underwent similar Rh(I)-catalyzed cycloisomerization
reaction under the standard conditions to give the
corresponding tetrahydroazepines 33, 34, and 3030 as a
sole product (Table 8).
product
and
entry substrate
R
catalyst
time (h) yield (%)
1
2
3
4
5
14a
14b
14c
14a
14b
H
[RhCl(CO)dppp]2
12
48
120
6
35a (22)a
35b (19)b
35c (49)
35a (58)
15b (14) +
35b (34)c
15c (12) +
35c (60)d
35c (77)
TMS [RhCl(CO)dppp]2
Ph
H
[RhCl(CO)dppp]2
[RhCl(CO)2]2
TMS [RhCl(CO)2]2
6
6
14c
Ph
[RhCl(CO)2]2
12
7
8
9
14c
14c
14c
Ph
Ph
Ph
[RhCl(CO)2]2
[RhCl(CO)2]2
[RhCl(CO)2]2
120
20
12
e
f
15c (62)
15c (10) +
35c (80)
a Compound 14a was recovered in 2% yield. b Compound 14b
was recovered in 49% yield. c Compound 14b was recovered in 16%
yield. d Compound 14c was recovered in 24% yield. e Heated at 80
°C. f Refluxed in xylene.
We next investigated rhodium(I)-catalyzed cycloisomer-
ization of 2-methyl-4-phenylsulfonyldeca-2,3-dien-9-yne
derivatives (tetrasubstituted allenes), which would afford
the cycloheptene skeleton possessing a 2-propenyl moiety
at the C2-position. Thus, allenyne 14a was refluxed in
toluene for 12 h in the presence of 2.5 mol % of [RhCl-
(CO)dppp]2 to give unexpectedly the bicyclo[5.2.0]nonene
compound 35a in 22% yield instead of the triene deriva-
tive 15a along with the recovery of a small amount of
the starting material 14a (2%) (Table 9, entry 1). Bicyclo-
[5.2.0] frameworks 35b,c were also formed under similar
conditions, but the corresponding triene derivatives 15b,c
could not be isolated from the reaction mixture (entries
2 and 3). [RhCl(CO)2]2 catalyzed the formation of the
bicyclo[5.2.0] skeleton to afford 35a-c more effectively
(entries 4-6). The structure of 35 was elucidated by
spectral evidence.31 Furthermore, X-ray crystallographic
(28) Compounds 7d (6%), 7e (31%), and 7f (48%) were obtained with
recovery of the starting materials 5d (72%), 5e (51%), and 5f (36%),
respectively.
(29) [RhCl(COD)2]2 was found not to be a suitable catalyst for
transformation of 10 into 12 [12a (30%), 12b (13%), and 12c (16%)].
(30) The stereochemistry of tetrahydroazepine derivatives was
determined by comparison of 1H NMR spectra with those of carbon
congeners.
J. Org. Chem, Vol. 70, No. 18, 2005 7165

Mukai et al.
analysis32 of 35c unambiguously established its structure
as depicted. To obtain more information on the transfor-
mation of alleynes 14 into 35, several experiments were
performed using phenyl derivative 14c. As mentioned
earlier, 14c produced 35c (60%) and the triene derivative
15c (12%) along with the starting 14c (24%) upon
exposure to [RhCl(CO)2]2 in refluxing toluene for 12 h
(entry 6). When the reaction time was prolonged to 120
h under the same conditions, exclusive formation of 35c
in 77% was observed (entry 7). On the other hand, the
cycloisomerization reaction of 14c at lower reaction
temperature (80 °C in toluene) for 20 h furnished the
triene compound 15c in 62% yield as a sole product (entry
8). Refluxing in xylene fairly shortened the reaction time
(12 h) leading to the formation of 35c in 80% yield along
with 15c in 10% yield (entry 9).
TABLE 10. Rh(I)-Catalyzed Cycloisomerization of
Compounds 36 under an Atmosphere of N2
entry substrate
R
time (h) product and yield (%)
1
2
3
4
5
36a
36b
36c
36d
36e
Ph
1
1
37a (88)
p-MeOC6H4
p-NO2C6H4
CO2Eta
37b (87)
1
37c (84)
12
6
37d (19) + 38d (43)b
37e (21) + 38e (3)
CH2OH
a Refluxed in xylene for 12 h. b Compounds 37d (12%) and 38d
(56%) were obtained when refluxed in xylene for 1 h.9
The formation of 35 can be attributable to a thermal
4π-electrocyclic reaction33 of the primarily formed triene
derivatives 15, and transformation of the latter to the
former seemed to require refluxing temperature in xy-
lene. Thus, compound 15c was refluxed in xylene for 9 h
in the absence of a rhodium catalyst to give a mixture
of 15c and 35c in a ratio of 30:70.34 A similar mixture
(15c/35c ) 30:70) was obtained when 35c was exposed
to xylene refluxing conditions for 9 h. These transforma-
tion reactions suggested that the bicyclo[5.2.0]nonene
framework is thermodynamically more stable than the
corresponding triene derivative.35 Rhodium catalyst was
found to accelerate the conversion of 15 into 35. As a
matter of fact, a solution of 15c in xylene was refluxed
for 9 h in the presence of 2.5 mol % of [RhCl(CO)2]2 to
furnish 35c in 60% yield along with the recovery of 15c
in 11% yield.
SCHEME 7
The tetrasubstituted allene 22g having an N-tosyla-
mide functionality behaved similarly to the carbon
congeners 14 and 36. The exclusive construction of the
tetrahydroazepine derivative 32 in 81% yield was ob-
served when 22g was refluxed in toluene in the presence
of 2.5 mol % of [RhCl(CO)2]2, whereas the bicyclo[5.2.0]-
nonene framework 39 (54%) was formed in a highly
selective manner under xylene refluxing conditions
(Scheme 7).
Some additional tetrasubstituted allenes 3636 with a
terminal methyl group were exposed to 2.5 mol % of
[RhCl(CO)2]2 in refluxing xylene. The results were sum-
marized in Table 10. Tetrasubstituted allene 36a pos-
sessing a phenyl group at the allenic terminus gave the
bicyclo[5.2.0] compound 37a in 88% yield (Table 10, entry
1). The electronic property on the aromatic ring of an
allenic terminus did not affect this transformation. Thus,
p-methoxy and p-nitro derivatives 36b,c provided the
corresponding bicyclic compounds 37b,c in high yield
(entries 2 and 3). Compound 36d having an ethoxy-
carbonyl group instead of a phenyl group also produced
the bicyclo[5.2.0] derivative 37d in rather lower yield
(19%). The triene derivative 38d was obtained as a major
product even for a prolonged reaction time (12 h) (entry
4). A terminal hydroxyl group tolerates this transforma-
tion to give 37e in 21% yield along with a small amount
of 38e (entry 5).
Interestingly, exclusive formation of triene derivatives
41 having a trisubstituted olefin functionality at the C2-
position was observed when the allene 40 with a diethyl
group at the allenic terminus was submitted to xylene
refluxing conditions (Scheme 8). The corresponding bi-
cyclo[5.2.0] derivative 42 could not be detected in the
reaction mixture. The cyclohexyl derivative 43 also
produced 44 in a high yield instead of 45. These observa-
tions were in sharp contrast to those observed in the
cycloisomerization of compounds 14, 22g, and 36 under
refluxing xylene conditions, where the formation of
bicyclo[5.2.0] derivatives via the intermediacy of the
triene derivatives commonly having a 1,1-disubstituted
olefin functionality at the C2-position was observed. On
the other hand, no formation of bicyclo[4.2.0]nonene
skeleton 46 could be detected in the cycloisomerization
reaction of 4-phenylsulfonylnona-2,3-dien-8-yne deriva-
tives 5 under toluene refluxing conditions (see Table 6).
The cyclohexene derivatives 7 with a vinyl or a propenyl
group at the C2-position, which are regarded as presum-
able intermediates for the construction of bicyclo[4.2.0]-
nonene derivatives 46, were refluxed in xylene to afford
only an intractable mixture or the recovery of 7. In
addition, conversion of the cycloheptene derivatives 12
into the bicyclo[5.2.0] derivatives 37 could not be realized
(Scheme 8).37
(31) For example, an NOE experiment of 35b showed 6.1% enhance-
ment of methyl group upon irradiation of vinyl proton, while 5.6%
enhancement between methyl group and vinyl proton of 35c was
observed.
(32) Data for crystallographic analysis of 35c was described in the
Supporting Information.
(33) (a) Doorakian, G. A.; Freedman, H. H. J. Am. Chem. Soc. 1968,
90, 3582-3584. (b) Doorakian, G. A.; Freedman, H. H. J. Am. Chem.
Soc. 1968, 90, 5310-5311. (c) Dolbier, W. R., Jr.; Koroniak, H.; Houk,
K. N.; Sheu, C. Acc. Chem. Res. 1996, 29, 471-477 and references
therein.
(34) Determined by 1H NMR.
(35) Compounds 15c (10%) and 35c (42%) were isolated after
refluxing a solution of 15c in xylene for 9 h.
(36) Compounds 36 were prepared by the standard procedure
described in this paper; see the Supporting Information.
7166 J. Org. Chem., Vol. 70, No. 18, 2005

Rh(I)-Catalyzed Pauson-Khand Reaction of Allenynes
SCHEME 8
FIGURE 1. Conformational analysis of cyclohexene and
cycloheptene derivatives.
To summarize the results so far obtained, there are
several comments concerning the formation of the cy-
clobutene-fused bicyclic frameworks such as bicyclo[5.2.0]-
nonenes via thermal 4π-electrocyclic reaction, which
should deserve mention. (i) The thermal 4π-electrocyclic
reaction leading to cyclobutene-fused bicyclic frameworks
proceeds whenever the substrates not only have a seven-
membered basic skeleton but also a 1,1-disubstituted
olefin moiety at the C2-position such as 15, 32, and 38.
In other words, one of two substituents at the allenic
terminus of the starting tetrasubstituted allenes has to
be a methyl group. (ii) Irrespective of the substitutent
at the triple bond terminus, cyclobutene formation can
be attained if the substrates meet the requirement (i).
(iii) Cycloheptene derivatives 12, 30, 33, 34, 41, and 44,
possessing a vinyl group, a 1,2-disubstituted olefin, or a
trisubstituted olefin moiety at the C2-position, were
unable to convert into the corresponding cyclobutene-
fused bicyclic compounds. (iv) Cyclohexene derivatives 7
never produced bicyclo[4.2.0] derivatives 46, even if
compounds 7 had a 1,1-disubstituted olefin moiety at the
C2-position.
Molecular model considerations of 3-alkylidene-2-vinyl-
1-phenylsulfonylcyclohex-1-ene as well as 3-alkylidene-
2-vinyl-1-phenylsulfonylcyclohept-1-ene skeletons pro-
vided clues to better understand the production of the
6-alkylidene-1-phenylsulfonylbicyclo[5.2.0]non-7-ene frame-
work (Figure 1). A molecular model of 3-alkylidene-2-
vinyl-1-phenylsulfonylcyclohept-1-ene skeletons indicates
that the alkylidene moiety at the C3-position must be out
of the plane p, on which a double bond between C1 and
C2, and an olefin moiety at the C2-position both exist.
There are two significant conformers, which should be
considered for cycloheptene derivatives with a vinyl group
or a 1,1-di-substituted olefin part at the C2-position; one
is A1 and the other A2. Conformer A1 (R′ ) alkyl) would
suffer from a serious nonbonding interaction with a
phenylsulfonyl group. This would not be the case with
conformer A2 where unfavorable interaction could not be
predicted. By that means, conformer A2 (R′ ) alkyl) must
be thermodynamically preferred over conformer A1, the
former of which would therefore readily undergo a
thermal 4π-electrocyclic reaction resulting in the forma-
tion of the bicyclo[5.2.0]nonene framework. In the case
of cycloheptene derivatives (R′ ) H), however, both
conformers A1 and A2 no longer have such a significantly
unfavorable interaction with a phenylsulfonyl group.
Therefore, conformational bias due to the rotational
barrier of a vinyl group at the C2-position is not expected,
and this would make its reactivity toward 4π-electrocyclic
reaction very poor. A similar analysis would be applied
to cycoheptene derivatives having a trisubstituted olefin
functionality at the C2-position. Figure 1 shows two
possible conformers A3 and A4 for compound 44 as a
typical example. Conformer A3 has a nonbonding interac-
tion with a phenylsulfonyl group like conformer A1 does.
This unfavorable interaction would shift the equilibrium
to a more stable conformer A4, which might be expected
to produce the corresponding cyclobutene derivative 45
(see Scheme 8). Because the thermal 4π-electrocylic
reaction proceeds reversibly in a conrotatory ring-closing
mode,33 conformer A4 must produce 45 with a cis-
stereochemical relationship between a phenylsulfonyl
group and the Ca-Cb bond of the cyclohexyl ring, and
this steric congestion would exclusively lead to 44 from
45.38 The conformation of 3-alkylidene-2-vinylcyclohex-
1-ene is quite different from that of 3-alkylidene-2-
vinylcyclohept-1-ene. As can be seen in Figure 1, exami-
(37) Compounds 12d,e were exposed to xylene refluxing conditions
leading to an intractable mixture.
J. Org. Chem, Vol. 70, No. 18, 2005 7167

Mukai et al.
nation of the molecular model indicates that six sp2-
hybridized carbon centers involving C1, C2, C3, and the
C2-vinyl group can exist on the same plane. There are
three possible conformers, B1, B2, and B3, which must
be considered for understanding the most preferred
conformer. Conformer B1, leading to the cyclobutene
derivative, would suffer from an unfavorable nonbonding
interaction between Ha and R′ on the vinyl group at the
C2-position, whereas a more serious interaction of a
phenylsulfonyl group with R′ as well as other interactions
between two vinyl hydrogens are predicted in conformer
B3. However, the C2-vinyl group of conformer B2 can
orient perpendicular to the plane, which consists of a
double bond between C1 and C2, and a C3-alkylidene
moiety, to avoid a nonbonding interaction with not only
a phenylsulfonyl group but also the C3-alkylidene moiety.
Therefore, conformer B2 seems to be the most stable
conformer among them. The fact that the bicyclo[4.2.0]-
octene framework could not be formed might reflect the
stability of conformer B2.
In summary, we have disclosed that the rhodium(I)-
catalyzed PKR of allenynes can be applicable for con-
structing azabicyclo[5.3.0]decadienone as well as oxabi-
cyclo[5.3.0]decadienone frameworks. A reliable procedure
for constructing a 10-monosubstituted-bicyclo[5.3.0]deca-
1,7-dien-9-one ring system by the rhodium(I)-catalyzed
PKR of allenynes was also developed under the condition
of 10 atm of CO. Investigation of the rhodium(I)-catalyzed
cycloisomerization of 4-phenylsulfonylnona-2,3-dien-8-
ynes under nitrogen atmosphere gave the corresponding
cyclohexene derivatives, whereas the C1-homologated
allenynes produced cycloheptene derivatives and/or bicyclo-
[5.2.0]nonene skeletons depending on the substitution
pattern at the allenic terminus. Thus, proper choice of
the starting allenynes and reaction conditions led to the
selective formation of 2-phenylsulfonylbicyclo[5.3.0]deca-
1,7-dien-9-ones (Pauson-Khand-type product), 3-alky-
lidene-1-phenylsulfonyl-2-vinylcycloheptene derivatives,
and bicyclo[5.2.0]nonene frameworks. The application of
this rhodium(I)-catalyzed PKR as well as the cyclo-
isomerization reaction of allenynes to the synthesis of
bioactive compounds is now in progress.
9-(Trimethylsilyl)-3,8-nonadiyn-2-ol (4b). To a solution
of 4a (102 mg, 0.750 mmol) in THF (4 mL) was added nBuLi
in hexane (1.4 M, 1.6 mL, 2.3 mmol) at -78 °C. After the
mixture was stirred for 1 h, TMSCl (0.60 mL, 4.5 mmol) was
added at -78 °C, and the reaction mixture was stirred for 15
min at room temperature. Then, 10% aqueous HCl was added
to the reaction mixture, which was stirred for 30 min and then
extracted with AcOEt. The extract was washed with water and
brine, dried, and concentrated to dryness. The residual oil was
chromatographed with hexane-AcOEt (6:1) to afford 4b (161
1
mg, 76%) as a colorless oil: IR 3605, 2172 cm-1; H NMR δ
4.50-4.46 (m, 1H), 2.29 (t, 2H, J ) 6.9 Hz), 2.28 (dt, 2H, J )
6.9, 2.0 Hz), 1.68 (quin, 2H, J ) 6.9 Hz), 1.40 (d, 3H, J ) 6.6
Hz); 13C NMR δ 106.2, 85.1, 83.4, 82.8, 58.4, 27.6, 24.6, 19.0,
17.7, 0.1; MS m/z 208 (M+, 3.8); HRMS calcd for C12H20OSi
208.1283, found 208.1280.
9-Phenyl-3,8-nonadiyn-2-ol (4c).10b To a solution of 4a
(134 mg, 0.990 mmol) in THF (5 mL) were successively added
CuI (3.8 mg, 2.0 × 10-2 mmol), Pd(PPh3)2Cl2 (6.9 mg, 1.0 ×
10-2 mmol), and iodobenzene (0.20 mL, 2.0 mmol). After the
mixture was stirred for 5 min at room temperature, iPr2NH
(1.4 mL, 10 mmol) was added, and the mixture was further
stirred for 15 h. The precipitates were filtered off, and the
filtrate was concentrated to leave a residual oil, which was
chromatographed with hexane-AcOEt (3:1) to afford 4c (177
mg, 85%) as a pale yellow oil: IR 3601, 2239 cm-1; 1H NMR δ
7.56-7.41 (m, 2H), 7.30-7.25 (m, 3H), 4.53-4.47 (m, 1H), 2.52
(t, 2H, J ) 7.0 Hz), 2.37 (t, 2H, J ) 7.0 Hz), 1.98-1.96 (m,
1H), 1.80-1.76 (m, 2H), 1.41 (d, 3H, J ) 7.2 Hz); 13C NMR δ
131.5, 128.2, 127.6, 123.7, 89.0, 83.5, 82.9, 81.2, 58.5, 27.8, 24.7,
18.5.
4-(Phenylsulfonyl)-2,3-nonadien-8-yne (5a). To a solu-
tion of 4a (186 mg, 1.37 mmol) and Et3N (0.60 mL, 4.1 mmol)
in THF (14 mL) was gradually added PhSCl (590 mg, 4.10
mmol) at -78 °C. After being stirred for 1.5 h at the same
temperature, the reaction was quenched by addition of satu-
rated aqueous NaHCO3, and the mixture was extracted with
AcOEt. The extract was washed with water and brine, dried,
and concentrated to dryness. The residue was passed through
a short pad of silica gel with hexane-AcOEt (6:1) to afford
the crude sulfoxide. To a solution of the crude sulfoxide in CH2-
Cl2 (12 mL) was added m-CPBA (300 mg, 1.70 mmol) at 0 °C.
After being stirred for 30 min, the reaction was quenched by
addition of saturated aqueous Na2S2O3 and NaHCO3, and the
mixture was extracted with CH2Cl2. The extract was washed
with brine, dried, and concentrated to dryness. The residue
was chromatographed with hexane-AcOEt (5:1) to afford 5a
(232 mg, 71% for two steps) as a colorless oil: IR 3308, 1960,
1306, 1150 cm-1; 1H NMR δ 7.91-7.87 (m, 2H), 7.65-7.50 (m,
3H), 5.74 (tq, 1H, J ) 7.3, 3.1 Hz), 2.41-2.34 (m, 2H), 2.17
(dt, 2H, J ) 6.9, 2.6 Hz), 1.90 (t, 1H, J ) 2.6 Hz), 1.73 (d, 6H,
J ) 7.3 Hz); 13C NMR δ 204.3, 140.2, 133.3, 129.0, 128.0, 112.1,
96.4, 83.2, 68.9, 26.4, 25.8, 17.5, 13.4; MS m/z 260 (M+, 0.6);
HRMS calcd for C15H16O2S 260.0871, found 260.0881.
N-(5-Hydroxy-3-pentynyl)-N-2-propynyl-(4-methylben-
zene)sulfonamide (21a). To a solution of 1617a (790 mg, 3.80
mmol), PPh3 (1.1 g, 4.1 mmol), and 1826a (597 mg, 3.24 mmol)
in THF (10 mL) was added dropwise DEAD (0.74 mL, 4.1
mmol) at 0 °C. After the mixture was stirred for 2 h at room
temperature, THF was evaporated off. The residue was passed
through a short pad of silica gel with hexane-AcOEt (7:1) to
afford the crude sulfonamide. To a solution of the crude
sulfonamide in EtOH (15 mL) was added PPTS (63 mg, 0.25
mmol) at room temperature. Afrer the mixture was stirred for
3 h at 55 °C, EtOH was evaporated off. Chromatography of
the residue with hexane-AcOEt (2:1) afforded 21a (505 mg,
53%) as a colorless oil: IR 3607, 3520, 3306, 1348, 1306, 1163
cm-1; 1H NMR δ 7.74 (d, 2H, J ) 8.3 Hz), 7.30 (d, 2H, J ) 8.3
Hz), 4.24-4.22 (m, 2H), 4.19 (d, 2H, J ) 2.3 Hz), 3.38 (t, 2H,
J ) 7.3 Hz), 2.56 (tt, 2H, J ) 7.3, 2.2 Hz), 2.43 (s, 3H), 2.08 (t,
1H, J ) 2.3 Hz), 1.74 (br s, 1H); 13C NMR δ 143.7, 135.6, 129.5,
127.5, 82.1, 80.5, 73.9, 50.9, 45.3, 37.0, 21.4, 18.9; MS m/z 291
Experimental Section
3,8-Nonadiyn-2-ol (4a).10a EtMgBr in THF (1.0 M, 5.2 mL,
5.2 mmol) was added to a 0 °C solution of 1,6-heptadiyne (3)
(400 mg, 19.7 mmol) in THF (8 mL). After the mixture was
heated at 50 °C for 1 h and then cooled to 0 °C, acetaldehyde
(0.30 mL, 5.2 mmol) was rapidly added. The reaction mixture
was further stirred for 15 min at 0 °C and then poured into
water. The resulting mixture was extracted with Et2O, and
the extract was washed with water and brine, dried, and
concentrated to dryness. The residue was chromatographed
with hexane-AcOEt (5:1) to afford 4a (355 mg, 60%) as a
1
colorless oil: IR 3308 cm-1; H NMR δ 4.51 (tq, 1H, J ) 7.0,
2.0 Hz), 2.37-2.27 (m, 4H), 1.97 (t, 1H, J ) 2.0 Hz), 1.73 (tt,
2H, J ) 7.0, 7.0 Hz), 1.43 (d, 3H, J ) 7.0 Hz); 13C NMR δ
83.5, 83.2, 83.0, 68.9, 58.5, 27.4, 24.6, 17.6, 17.5.
(38) We tried to convert 44 into 45 with a trans-relationship between
a phenylsulfonyl group and the Ca-Cb bond by a disrotatory ring-
closing mode. Thus, a solution of 44 in CH2Cl2 was irradiated with a
high-pressure mercury lamp through a Pyrex filter to afford a mixture
of 44 and its isomer with (Z)-benzylidene group at the C3-position. The
formation of 45 with a trans-relationship between a phenylsulfonyl
group and the Ca-Cb bond could not be detected.
7168 J. Org. Chem., Vol. 70, No. 18, 2005

Rh(I)-Catalyzed Pauson-Khand Reaction of Allenynes
(M+, 0.1); HRMS calcd for C15H17NO3S 291.0929, found
291.0923.
AcOEt to afford cyclized products. Chemical yields are sum-
marized in Tables 1, 2, 4, and 5.
General Procedure for Ring-Closing Reaction with
Rh(I) Catalyst under 5-20 atm of CO. To a solution of
allenyne (0.10 mmol) in toluene (1.0 mL) was added 2.5 mol
% of [RhCl(CO)2]2. The reaction mixture was heated at 120
°C (the oil bath temperature) under CO pressure shown in the
tables until the complete disappearance of the starting mate-
rial as indicated by TLC. Toluene was evaporated off, and the
residual oil was chromatographed with hexane-AcOEt to
afford cyclized products. Chemical yields are summarized in
Tables 2-4 and Schemes 4 and 6.
General Procedure for Ring-Closing Reaction with
Rh(I) Catalyst under N2. To a solution of allenyne (0.10
mmol) in toluene or xylene (1.0 mL) was added 2.5 mol % of
Rh(I) catalyst. The reaction mixture was refluxed under a N2
atmosphere until the complete disappearance of the starting
material as indicated by TLC. Solvent was evaporated off, and
the residual oil was chromatographed with hexane-AcOEt to
afford cyclized products. Chemical yields are summarized in
Tables 6-10 and Schemes 7 and 8.
9-Methyl-2-(phenylsulfonyl)bicyclo[4.3.0]nona-1,6-dien-
8-one (6a): colorless plates; mp 88-88.5 °C (Et2O); IR 1705,
1308, 1151 cm-1; 1H NMR δ 7.90-7.87 (m, 2H), 7.68-7.53 (m,
3H), 6.12 (s, 1H), 3.58 (q, 1H, J ) 7.3 Hz), 2.77-2.57 (m, 2H),
2.48 (dt, 2H, J ) 17.5, 5.6 Hz), 2.27-2.16 (m, 1H), 1.85-1.74
(m, 2H), 1.54 (d, 3H, J ) 7.3 Hz); 13C NMR δ 207.0, 167.2,
148.9, 139.5, 134.3, 133.8, 130.4, 129.3, 128.0, 43.5, 25.82,
25.79, 21.7, 18.4; MS m/z 288 (M+, 26.3). Anal. Calcd for
C16H16O3S: C, 66.64; H, 5.59. Found: C, 66.57; H, 5.61.
N-[3-(Phenylsulfonyl)-3,4-pentadienyl]-N-2-propynyl-
(4-methylbenzene)sulfonamide (22a). According to the
same procedure described for preparation of 5a, 22a (304 mg,
72%) was obtained from 21a (297 mg, 1.02 mmol) as colorless
needles: mp 111.5-113 °C (hexane-AcOEt); IR 3308, 1969,
1
1936, 1350, 1308, 1161 cm-1; H NMR δ 7.94-7.90 (m, 2H),
7.69-7.53 (m, 5H), 7.30-7.26 (m, 2H), 5.43 (t, 2H, J ) 2.8
Hz), 4.03 (d, 2H, J ) 2.3 Hz), 3.33 (t, 2H, J ) 6.8 Hz), 2.60-
2.52 (m, 2H), 2.42 (s, 3H), 2.01 (t, 1H, J ) 2.3 Hz); 13C NMR
δ 208.1, 143.7, 139.6, 135.5, 133.6, 129.5, 129.1, 128.1, 127.5,
109.6, 85.0, 76.3, 74.0, 44.9, 36.7, 25.6, 21.5; MS m/z 415 (M+,
0.6). Anal. Calcd for C21H21NO4S2: C, 60.70; H, 5.10; N, 3.32.
Found: C, 60.61; H, 5.10; N, 3.32.
5-(2-Propynyloxy)-2-pentyn-1-ol (24a). tBuOK (300 mg,
2.70 mmol) was added to a solution of 18 (103 mg, 0.559 mmol)
in THF (6 mL) at 0 °C. After the mixture was stirred for 30
min, propargyl bromide (0.60 mL, 6.7 mmol) was added at 0
°C. The mixture was further stirred overnight at room tem-
perature, and the reaction mixture was quenched by addition
of water, extracted with Et2O, washed with water and brine,
dried, and concentrated to dryness. Chromatography of the
residue with hexane-AcOEt (7:1) gave 23a (120 mg). To a
solution of 23a (457 mg, 2.05 mmol) in EtOH (16 mL) was
added PPTS (52 mg, 0.21 mmol) at room temperature. The
mixture was stirred for 1.5 h at 55 °C and then cooled to room
temperature. The reaction mixture was concentrated to dry-
ness, and the residue was chromatographed with hexane-
AcOEt (2:1) to give 24a (273 mg, 92% for two steps) as a pale
yellow oil: IR 3609, 3308 cm-1; 1H NMR δ 4.24-4.18 (m, 4H),
3.64 (t, 2H, J ) 6.8 Hz), 2.52 (tt, 2H, J ) 6.8, 2.3 Hz), 2.44 (t,
1H, J ) 2.3 Hz), 1.97 (m, 1H); 13C NMR δ 82.2, 79.6, 79.1,
74.7, 67.8, 57.9, 50.7, 19.7; MS m/z 138 (M+, 0.1); HRMS calcd
for C8H10O2 138.0681, found 138.0683.
9,9-Dimethyl-2-(phenylsulfonyl)-7-(trimethylsilyl)bi-
cyclo[4.3.0]nona-1,6-dien-8-one (6e): pale yellow plates; mp
122 °C (Et2O); IR 1692, 1308, 1155 cm-1 1H NMR δ 7.92-
;
7.88 (m, 2H), 7.67-7.52 (m, 3H), 2.68 (t, 2H, J ) 6.3 Hz), 2.31
(t, 2H, J ) 6.3 Hz), 1.74 (tt, 2H, J ) 6.3, 6.3 Hz), 1.54 (s, 6H),
0.26 (s, 9H); 13C NMR δ 212.9, 172.1, 153.3, 141.6, 140.0, 134.6,
133.4, 129.2, 127.8, 47.2, 27.6, 27.4, 22.6, 22.0, -0.7; MS m/z
374 (M+, 26). Anal. Calcd for C19H20O3SSi: C, 64.13; H, 7.00.
Found: C, 64.06; H, 7.13.
5-(3-Trimethylsilyl-2-propynyloxy)-2-pentyn-1-ol (24b).
nBuLi (4.8 mL, 6.4 mmol, 1.4 M in hexane) was added to a
solution of 23a (954 mg, 4.28 mmol) in THF (9.0 mL) at -78
°C. After the mixture was stirred for 1 h, TMSCl (1.6 mL, 13
mmol) was added at same temperature. The mixture was
stirred for 1 h at room temperature, and the reaction mixture
was quenched by addition of water, extracted with AcOEt,
washed with water and brine, dried, and concentrated to
dryness. Chromatography of the residue with hexane-AcOEt
(8:1) gave 23b (670 mg). To a solution of 23b in EtOH (18 mL)
was added PPTS (57 mg, 0.23 mmol) at room temperature.
Then the mixture was stirred for 3 h at 55 °C, and the reaction
mixture was concentrated to dryness. Chromatography of the
residue with hexane-AcOEt (3:1) gave 24b (336 mg, 36% for
2-Ethenyl-3-methylene-1-(phenylsulfonyl)cyclohex-
1
ene (7a): colorless oil; IR 1306, 1148 cm-1; H NMR δ 7.86-
7.84 (m, 2H), 7.59-7.55 (m, 1H), 7.51-7.48 (m, 2H), 6.79 (ddt,
1H, J ) 17.7, 11.7, 1.7 Hz), 5.44-5.42 (m, 2H), 5.21-5.20 (m,
1H), 5.10 (dd, 1H, J ) 17.7, 1.7 Hz), 2.58-2.55 (m, 2H), 2.36-
2.33 (m, 2H), 1.78-1.73 (m, 2H); 13C NMR δ144.8, 142.5, 141.5,
136.1, 133.0, 131.8, 128.8, 127.6, 121.5, 119.9, 31.5, 27.3, 22.6;
MS m/z 260 (M+, 0.5); HRMS calcd for C15H16O2S 260.0871,
found 260.0867.
2-(1-Methylethenyl)-1-(phenylsulfonyl)-3-[(E)-(trime-
thylsilyl)methylene]cyclohexene (7e): colorless oil; IR
1304, 1150 cm-1; 1H NMR δ 7.90-7.84 (m, 2H), 7.60-7.45 (m,
3H), 5.98 (s, 1H), 5.17-5.16 (m, 1H), 4.57-4.56 (m, 1H), 2.55-
three steps) as a pale yellow oil: IR 3609, 3433, 2174 cm-1
;
1H NMR δ 4.25-4.18 (m, 4H), 3.63 (t, 2H, J ) 6.9 Hz), 2.53
(tt, 2H, J ) 6.9, 2.0 Hz), 1.72 (s, 1H), 0.18 (s, 9H); 13C NMR δ
101.0, 91.6, 82.7, 79.5, 67.9, 58.9, 51.2, 19.9, -0.3; MS m/z 210
(M+, 0.1); HRMS calcd for C11H18O2Si 210.1076, found 210.1062.
2.53 (m, 4H), 1.84 (s, 3H), 1.80-1.58 (m, 2H), 0.11 (s, 9H); 13
C
NMR δ 150.7, 148.5, 141.7, 141.1, 135.7, 134.5, 132.9, 128.7,
128.0, 117.0, 30.3, 27.2, 24.1, 22.6, -0.3; MS m/z 346 (M+, 0.2);
HRMS calcd for C19H26O2SSi 346.1423, found 346.1430.
3-(Phenylsulfonyl)-5-(2-propynyloxy)-1,2-pentadiene
(25a). According to the same procedure described for prepara-
tion of 5a, 25a (463 mg, 82%) was obtained from 24a (301 mg,
2.18 mmol) as a colorless oil: IR 3308, 1971, 1938, 1308, 1151
10-Methyl-2-(phenylsulfonyl)bicyclo[5.3.0]deca-1,7-dien-
9-one (11a): colorless oil; IR 1705, 1308, 1148 cm-1; 1H NMR
δ 7.90-7.88 (m, 2H), 7.67-7.55 (m, 3H), 6.12 (s, 1H), 3.59 (q,
1H, J ) 7.3 Hz), 2.74-2.54 (m, 2H), 2.25-2.19 (m, 1H), 1.84-
1.75 (m, 4H), 1.53 (d, 3H, J ) 7.3 Hz); 13C NMR δ 207.3, 172.8,
152.6, 139.9, 136.6, 133.64, 133.59, 129.3, 127.8, 46.4, 28.8,
26.5, 25.8, 22.8, 19.6; MS m/z 302 (M+, 1.7); HRMS calcd for
C17H18O3S 302.0977, found 302.0976.
1
cm-1; H NMR δ 7.92-7.89 (m, 2H), 7.67-7.51 (m, 3H), 5.40
(t, 2H, J ) 3.3 Hz), 4.06 (d, 2H, J ) 2.3 Hz), 3.61 (t, 2H, J )
6.6 Hz), 2.55 (tt, 2H, J ) 6.6, 3.3 Hz), 2.39 (t, 1H, J ) 2.3 Hz);
13C NMR δ 208.1, 140.0, 133.5, 129.1, 128.1, 109.9, 84.4, 79.3,
74.6, 67.1, 58.0, 27.2; MS m/z 262 (M+, 0.4); HRMS calcd for
C14H14O3S 262.0664, found 262.0673.
General Procedure for Ring-Closing Reaction with
Rh(I) Catalyst under an Atmosphere of CO. To a solution
of allenyne (0.10 mmol) in toluene (1.0 mL) was added 2.5 mol
% of Rh(I) catalyst. The reaction mixture was refluxed under
a CO atmosphere until the complete disappearance of the
starting material as indicated by TLC. Toluene was evaporated
off, and the residual oil was chromatographed with hexane-
2-Ethenyl-3-methylene-1-(phenylsulfonyl)cyclohep-
1
tene (12a): colorless oil; IR 1308, 1148 cm-1; H NMR δ 7.97
(dd, 1H, J ) 17.0, 11.0 Hz), 7.90-7.48 (m, 5H), 5.56 (dd, 1H,
J ) 17.0, 1.7 Hz), 5.48 (dd, 1H, J ) 11.0, 1.7 Hz), 5.35 (d, 1H,
J ) 1.0 Hz), 4.80 (d, 1H, J ) 1.0 Hz), 2.55-2.50 (m, 2H), 2.15-
2.11 (m, 2H), 1.71-1.62 (m, 2H), 1.37-1.29 (m, 2H); 13C NMR
δ 152.2, 145.9, 141.6, 134.7, 133.0, 131.8, 129.0, 127.2, 124.0,
J. Org. Chem, Vol. 70, No. 18, 2005 7169

Mukai et al.
116.8, 33.9, 30.8, 30.1, 24.7; MS m/z 274 (M+, 5.0); HRMS calcd
for C16H18O2S 274.1028, found 274.1019.
120.8, 49.0, 45.4, 27.1, 21.5, 20.5, -0.6; MS m/z 512 (M+, 1.2).
Anal. Calcd for C26H33NO4S2Si: C, 60.55; H, 6.45; N, 2.72.
Found: C, 60.46; H, 6.73; N, 2.64.
3-Methylene-2-(1-methylethenyl)-1-(phenylsulfonyl)-
cycloheptene (15a): colorless oil; IR 1304, 1146 cm-1
;
1H
4-Ethenyl-1-(4-methylbenzenesulfonyl)-3-methylene-
5-(phenylsulfonyl)-2,3,6,7-tetrahydro-1H-azepine (33): col-
orless plates; mp 73-74 °C (hexane-AcOEt); IR 1340, 1306,
1163, 1148 cm-1; 1H NMR δ 7.89-7.85 (m, 2H), 7.77-7.51 (m,
6H), 7.30-7.27 (m, 2H), 5.63-5.61 (m, 1H), 5.52-5.49 (m, 1H),
5.46-5.44 (m, 1H), 5.16-5.13 (m, 1H), 3.76 (s, 2H), 3.12 (t,
2H, J ) 6.0 Hz), 2.73 (t, 2H, J ) 6.0 Hz), 2.42 (s, 3H); 13C
NMR δ 149.8, 143.6, 141.0, 140.7, 133.3, 132.9, 131.5, 129.8,
129.28, 129.27, 127.3, 127.2, 124.9, 121.9, 50.6, 44.8, 29.8, 21.5;
MS m/z 429 (M+, 2.4); HRMS calcd for C22H23NO4S 429.1068,
found 429.1068. Anal. Calcd for C22H23NO4S2: C, 61.51; H,
5.40; N, 3.26. Found: C, 61.40; H, 5.57; N, 3.21.
NMR δ 7.88-7.86 (m, 2H), 7.58-7.48 (m, 3H), 5.24 (s, 1H),
5.20 (d, 1H, J ) 1.5 Hz), 5.01 (t, 1H, J ) 1.5 Hz), 4.76 (d, 1H,
J ) 1.0 Hz), 2.57-2.55 (m, 2H), 2.33 (t, 2H, J ) 6.4 Hz), 1.74-
1.69 (m, 5H), 1.60-1.57 (m, 2H); 13C NMR δ 155.7, 146.1,
143.6, 141.7, 138.1, 132.7, 128.7, 128.3, 118.9, 115.9, 34.5, 29.4,
29.1, 24.7, 21.6; MS m/z 288 (M+, 81); HRMS calcd for
C17H20O2S 288.1184, found 288.1187.
N-(4-Methylbenzenesulfonyl)-6-(phenylsulfonyl)-3-
azabicyclo[5.3.0]deca-1(10),6-dien-9-one (26a): colorless
plates; mp 172-173 °C (hexane-AcOEt); IR 1701, 1350, 1308,
1159 cm-1; 1H NMR δ 7.82-7.77 (m, 2H), 7.72-7.51 (m, 5H),
7.28-7.22 (m, 2H), 6.28 (s, 1H), 4.48 (s, 2H), 3.58 (t, 2H, J )
4-Ethenyl-1-(4-methylbenzenesulfonyl)-5-(phenylsul-
fonyl)-3-[(Z)-(trimethylsilyl)methylene]-2,3,6,7-tetrahy-
dro-1H-azepine (34): colorless needles; mp 49-50 °C (hexane-
6.3 Hz), 3.24 (s, 2H), 2.85 (t, 2H, J ) 6.3 Hz), 2.42 (s, 3H); 13
C
NMR δ 201.7, 166.2, 145.9, 144.2, 139.5, 136.9, 135.8, 134.1,
133.9, 129.8, 129.6, 127.6, 127.2, 47.4, 44.6, 41.0, 27.1, 21.5;
MS m/z 443 (M+, 17.4). Anal. Calcd for C22H21NO5S2: C, 59.57;
H, 4.77; N, 3.16. Found: C, 59.66; H, 4.94; N, 3.15.
1
AcOEt); IR 1352, 1306, 1165 cm-1; H NMR δ 8.01-7.94 (m,
2H), 7.83-7.61 (m, 6H), 7.50-7.26 (m, 2H), 5.77 (s, 1H), 5.57-
5.45 (m, 2H), 3.90 (s, 2H), 3.16 (t, 2H, J ) 6.1 Hz), 2.79 (t, 2H,
J ) 6.1 Hz), 2.54 (s, 3H), 0.28 (s, 9H); 13C NMR δ? 151.5, 148.1,
143.7, 141.2, 137.2, 134.0, 133.2, 131.6, 130.5, 129.8, 129.2,
127.4, 127.2, 124.9, 49.4, 44.9, 29.0, 21.5, -0.4; MS m/z 501
(M+, 0.7). Anal. Calcd for C25H31NO4S2Si: C, 59.85; H, 6.23;
N, 2.79. Found: C, 59.53; H, 6.47; N, 2.75.
6-(Phenylsulfonyl)-3-oxabicyclo[5.3.0]deca-1(10),6-dien-
9-one (27a): colorless oil; IR 1705, 1308, 1151 cm-1; 1H NMR
δ 7.90-7.87 (m, 2H), 7.67-7.55 (m, 3H), 6.30 (s, 1H), 4.67 (s,
2H), 3.91 (t, 2H, J ) 5.6 Hz), 3.61 (s, 2H), 2.99 (t, 2H, J ) 5.6
Hz); 13C NMR δ 201.9, 170.0, 145.1, 139.9, 135.9, 135.0, 133.9,
129.5, 127.6, 69.1, 66.6, 41.5, 31.1; MS m/z 290 (M+, 2.5);
HRMS calcd for C15H14O4S 290.0613, found 290.0614.
9-Methyl-2-methylene-7-(phenylsulfonyl)bicyclo[5.2.0]-
non-1(9)-ene (35a): colorless oil; IR 1296, 1138 cm-1; 1H NMR
δ 7.89-7.82 (m, 2H), 7.63-7.45 (m, 3H), 5.02 (s, 1H), 4.93 (s,
1H), 2.95-2.84 (m, 1H), 2.75-2.67 (m, 1H), 2.56-2.51 (m, 1H),
2.39 (dd, 1H, J ) 15.5, 6.6 Hz), 2.25-2.05 (m, 2H), 1.99-1.89
(m, 1H), 1.84-1.73 (m, 1H), 1.71-1.53 (m, 1H), 1.63 (s, 3H),
1.38-1.23 (m, 1H); 13C NMR δ 143.7, 142.4, 139.9, 136.8, 133.2,
129.6, 128.2, 112.3, 69.9, 42.6, 36.0, 33.6, 28.0, 27.3, 15.2;
FABMS m/z 289 (M++1, 6.2); FABHRMS calcd for C17H20O2S
289.1262, found 289.1266.
N-(4-Methylbenzenesulfonyl)-8-methyl-6-(phenylsul-
fonyl)-10-(trimethylsilyl)-3-azabicyclo[5.3.0]deca-
1(10),6-dien-9-one (28): colorless plates; mp 131-132 °C
(hexane-AcOEt); IR 1701, 1350, 1308, 1159, 1150 cm-1 1H
;
NMR δ 7.83-7.80 (m, 2H), 7.70-7.64 (m, 1H), 7.60-7.54 (m,
4H), 7.29-7.26 (m, 2H), 4.76 (d, 1H J ) 17.5 Hz), 4.25 (d, 1H,
J ) 17.5 Hz), 3.64 (q, 1H J ) 7.3 Hz), 3.41-3.20 (m, 2H), 2.78-
2.57 (m, 2H), 2.42 (s, 3H), 1.26 (d, 3H, J ) 7.3 Hz), 0.35 (s,
9H); 13C NMR δ 209.9, 172.1, 153.6, 147.9, 143.9, 139.5, 136.1,
133.9, 130.2, 129.7, 129.4, 127.7, 127.0, 46.6, 44.4, 27.1, 21.4,
18.9, -0.8; MS m/z 529 (M+, 0.7); HRMS calcd for C26H31NO5S2-
Si 529.1413, found 529.1420.
9-Phenyl-2-[(E)-6-phenylmethylene]-7-(phenylsulfonyl)-
bicyclo[5.2.0]non-1(9)-ene (37a): colorless needles; mp 195-
195.5 °C (hexane); IR 1298, 1140 cm-1; 1H NMR δ 7.98 (d, 2H,
J ) 7.6 Hz), 7.61-7.26 (m, 13H), 6.89 (s, 1H), 3.12 (d, 1H, J )
14.0 Hz), 3.07-3.02 (m, 1H), 2.92-2.73 (m, 2H), 2.39 (d, 1H,
J ) 14.0 Hz), 2.23-2.11 (m, 1H), 2.10-1.73 (m, 3H), 1.54-
1.38 (m, 1H); 13C NMR δ 141.5, 138.8, 137.11, 137.07, 136.9,
133.7, 133.6, 129.7, 129.0, 128.6, 128.41, 128.36, 128.3, 127.0,
126.4, 69.3, 39.5, 34.2, 30.7, 27.6, 27.4; MS m/z 426 (M+, 0.1);
HRMS calcd for C28H26O2S 426.1653, found 426.1651.
2-[1-(Ethoxycarbonyl)ethenyl]-3-[(E)-phenylmethylene]-
1-(phenylsulfonyl)cycloheptene (38d): colorless oil; IR
4-Ethenyl-1-(4-methylbenzenesulfonyl)-3-[(Z)-phenyl-
methylene]-5-(phenylsulfonyl)-2,3,6,7-tetrahydro-1H-
azepine (30): colorless plates; mp 126-127 °C (hexane-
AcOEt); IR 1340, 1306, 1163, 1151 cm-1 1H NMR δ 7.80-
;
7.78 (m, 2H), 7.68 (dd, 2H, J ) 17.0, 10.5 Hz), 7.53-7.43 (m,
5H), 7.32-7.29 (m, 4H), 7.25-7.16 (m, 3H), 6.45 (s, 1H), 5.43
(dd, 1H, J ) 10.7, 1.5 Hz), 5.42 (dd, 1H, J ) 17.0, 1.5 Hz),
3.82 (s, 2H), 3.01 (t, 2H, J ) 6.1 Hz), 2.65 (t, 2H, J ) 6.1 Hz),
2.33 (s, 3H); 13C NMR δ 151.1, 143.8, 141.1, 136.5, 134.6, 133.6,
133.3, 132.8, 132.6, 132.2, 129.8, 129.4, 129.3, 128.6, 128.5,
127.6, 127.3, 125.3, 47.5, 45.6, 29.3, 21.5; MS m/z 505 (M+,
4.5). Anal. Calcd for C28H27NO4S2: C, 66.51; H, 5.38; N, 2.77.
Found: C, 66.38; H, 5.55; N, 2.72.
1
1717, 1304, 1144 cm-1; H NMR δ 7.89-7.85 (m, 2H), 7.62-
7.47 (m, 3H), 7.36-7.21 (m, 5H), 6.52 (d, 1H, J ) 1.2 Hz), 6.51
(s, 1H), 5.74 (d, 1H, J ) 1.2 Hz), 4.09 (q, 2H, J ) 7.2 Hz), 2.65
(t, 2H, J ) 6.1 Hz), 2.59 (t, 2H, J ) 6.1 Hz), 1.83 (quin, 2H, J
) 6.1 Hz), 1.55 (quin, 2H, J ) 6.1 Hz), 1.23 (t, 3H, J ) 7.2
Hz); 13C NMR δ 164.8, 149.3, 140.9, 140.3, 139.8, 138.5, 136.4,
133.3, 132.9, 129.3, 129.0, 128.7, 128.34, 128.28, 127.5, 60.9,
29.6, 28.7, 26.2, 24.3, 14.0; MS m/z 422 (M+, 1.8); HRMS calcd
for C25H26O4S 422.1552, found 422.1551.
N-(4-Methylbenzenesulfonyl)-8,8-dimethyl-6-(phenyl-
sulfonyl)-10-(trimethylsilyl)-3-azabicyclo[5.3.0]deca-
1(10),6-dien-9-one (31): colorless needles; mp 181-181.5 °C
(hexane-AcOEt); IR 1699, 1350, 1308, 1157 cm-1; 1H NMR δ
7.86-7.81 (m, 2H), 7.73-7.50 (m, 5H), 7.30-7.24 (m, 2H), 4.48
(s, 2H), 2.99 (t, 2H, J ) 6.3 Hz), 2.64 (t, 2H, J ) 6.3 Hz), 2.41
(s, 3H), 1.43 (s, 6H), 0.35 (s, 9H);13C NMR δ 212.0, 171.8, 157.7,
147.2, 144.0, 139.5, 136.0, 133.9, 131.9, 129.8, 129.4, 128.1,
127.0, 50.2, 46.2, 45.1, 28.9, 22.3, 21.5, -0.7; MS m/z 543 (M+,
8.3); HRMS calcd for C27H33NO5S2Si 543.1569, found 543.1569.
1-(4-Methylbenzenesulfonyl)-4-(1-methylethenyl)-5-
(phenylsulfonyl)-3-[(Z)-(trimethylsilyl)methylene]-2,3,6,7-
tetrahydro-1H-azepine (32): colorless needles; mp 52-53 °C
(hexane-AcOEt); IR 1350, 1306, 1161, 1142 cm-1; 1H NMR δ
7.91-7.90 (m, 2H), 7.65-7.63 (m, 3H), 7.58-7.48 (m, 2H),
7.33-7.32 (m, 2H), 5.92 (s, 1H), 5.09 (s, 1H), 5.04 (s, 1H), 3.93
(s, 2H), 3.37-3.36 (m, 2H), 2.74-2.72 (m, 2H), 2.43 (s, 3H),
1.14 (s, 3H), 0.13 (s, 9H); 13C NMR δ 154.4, 149.4, 143.6, 141.1,
140.6, 136.3, 135.4, 134.2, 132.8, 129.9, 129.2, 128.5, 127.0,
N-(4-Methylbenzenesulfonyl)-9-methyl-7-(phenylsul-
fonyl)-2-[(Z)-(trimethylsilyl)methylene]-4-azabicyclo-
[5.2.0]non-1(9)-ene (39): colorless oil; IR 1333, 1157, 1146
cm-1; 1H NMR δ 7.81-7.79 (m, 2H), 7.76-7.61 (m, 2H), 7.48-
7.45 (m, 2H), 7.27-7.25 (m, 3H), 5.47 (s, 1H), 4.65 (d, 1H, J )
6.6 Hz), 4.09-4.05 (m, 2H), 3.68-3.63 (m, 1H), 2.68-2.65 (m,
1H), 2.47-2.43 (m, 3H), 2.40 (s, 3H), 2.07-2.00 (m, 2H), 1.50
(s, 3H), 0.26 (s, 9H); 13C NMR δ 148.1, 145.0, 144.0, 139.9,
137.8, 135.8, 133.7, 129.6, 129.5, 128.2, 126.8, 68.8, 53.4, 49.9,
42.3, 33.9, 21.4, 15.0, 0.1; MS m/z 515 (M+, 0.9); HRMS calcd
for C26H33NO4S2Si 289.1262, found 289.1266.
2-[(E)- and (Z)-1-Methyl-1-propenyl]-3-[(E)-phenyl-
methylene]-1-(phenylsulfonyl)cycloheptene (41).
A
50:50 mixture of (E)- and (Z)-41 was obtained as colorless
plates: mp 73-74 °C (hexane-AcOEt); IR 1304, 1146 cm-1
;
7170 J. Org. Chem., Vol. 70, No. 18, 2005

Rh(I)-Catalyzed Pauson-Khand Reaction of Allenynes
1H NMR δ 7.89-7.83 (m, 2H), 7.59-7.50 (m, 3H), 7.36-7.24
(m, 5H), 6.60 (s, 50/100 × 1H), 6.56 (s, 50/100 × 1H), 5.54-
5.50 (m, 50/100 × 1H), 5.43 (q, 50/100 × 1H, J ) 6.6 Hz), 2.78-
2.73 (m, 50/100 × 1H), 2.69-2.46 (m, 50/100 × 6H), 2.34-
2.28 (m, 50/100 × 1H), 2.17-2.01 (m, 50/100 × 2H), 1.94 (q,
50/100 × 2H, J ) 7.6 Hz), 1.84-1.71 (m, 50/100 × 6H), 1.66-
1.51 (m, 50/100 × 5H), 1.47-1.42 (m, 50/100 × 1H), 1.07 (t,
50/100 × 3H, J ) 7.6 Hz), 0.92 (t, 50/100 × 3H, J ) 7.6 Hz);
13C NMR δ 158.0, 154.0, 142.4, 141.3, 140.9, 139.9, 139.5,
138.9, 137.9, 137.4, 137.3, 137.0, 136.8, 133.6, 132.7, 132.5,
129.0, 128.9, 128.8, 128.6, 128.33, 128.30, 128.29, 128.1, 127.5,
127.4, 127.3, 121.8, 29.9, 29.8, 29.5, 29.3, 28.8, 27.2, 26.9, 24.8,
24.7, 22.9, 15.4, 13.7, 13.0, 12.3; MS m/z 392 (M+, 0.3). Anal.
Calcd for C23H28O2S: C, 76.49; H, 7.19. Found: C, 76.35; H,
7.38.
2-(1-Cyclohexenyl)-3-[(E)-phenylmethylene]-1-(phen-
ylsulfonyl)cycloheptene (44): pale yellow oil; IR 1288, 1140
cm-1; 1H NMR δ 7.85-7.84 (m, 2H), 7.57-7.49 (m, 3H), 7.36-
7.23 (m, 5H), 6.59 (s, 1H), 5.59-5.58 (m, 1H), 2.73 (t, 2H, J )
5.6 Hz), 2.51-2.50 (m, 2H), 2.09-2.07 (m, 2H), 1.84 (quin, 2H,
J ) 6.2 Hz), 1.72 (quin, 2H, J ) 6.2 Hz), 1.67-1.66 (m, 2H),
1.52-1.47 (m, 2H), 1.44-1.39 (m, 2H); 13C NMR δ 157.0, 142.6,
139.6, 137.6, 136.8, 136.4, 132.6, 132.4, 130.0, 128.9, 128.6,
128.3, 127.8, 127.3, 29.9, 28.8, 27.2, 27.0, 25.3, 24.8, 22.2, 21.4;
MS m/z 404 (M+, 52.0); HRMS calcd for C26H28O2S 404.1810,
found 404.1800.
Acknowledgment. This work was supported in part
by a Grant-in Aid for Scientific Research from the
Ministry of Education, Culture, Sports, Science and
Technology, Japan, for which we are thankful.
Supporting Information Available: 1H and 13C NMR
spectra for compounds 4b,d-f, 5a,c,d,f, 6c, 7a-f, 9b-d,f,
10a-d,f, 11a,f, 12a-e, 13b,c, 14a, 15a-c, 21a,d, 24a,b,
25a,b, 27a, 28, 29, 31, 35a,c, 36a-e, 37a-c,e, 38d,e, 39, and
44; characterization data for compounds 4d-f, 5b-f, 6b,c,
7b-d, f, 9a-f, 10a-f, 11b-f, 12b-e, 13a-c, 14a-c, 15b,c,
21b-g, 22b-g, 25b, 26b,c, 27b, 29, 35b,c, 36a-e, 37b-e,
38e, 40, and 43; and X-ray crystallographic data for 35c. This
material is available free of charge via the Internet at
http://pubs.acs.org.
JO050770Z
J. Org. Chem, Vol. 70, No. 18, 2005 7171