Rh(I)-catalyzed intramolecular allenic Pauson-Khand reaction: Construction of a bicyclo[5.3.0]dec-1,7-dien-9-one skeleton

Article abstract of DOI:10.1021/ol020051w

Matrix presented 1-Phenylsulfonylallenes possessing a hexynyl appendage in refluxing toluene in the presence of catalytic amount of rhodium(I) catalyst under a carbon monoxide atmosphere underwent regioselective formal [2 + 2 + 1]-cycloaddition to produce

Full text of DOI:10.1021/ol020051w

ORGANIC
LETTERS
2002
Vol. 4, No. 10
1755-1758
Rh(I)-Catalyzed Intramolecular Allenic
Pauson−Khand Reaction: Construction
of a Bicyclo[5.3.0]dec-1,7-dien-9-one
Skeleton
Chisato Mukai,* Izumi Nomura, Kei Yamanishi, and Miyoji Hanaoka
Faculty of Pharmaceutical Sciences, Kanazawa UniVersity, Takara-machi,
Kanazawa 920-0934, Japan
cmukai@kenroku.kanazawa-u.ac.jp
Received March 6, 2002
ABSTRACT
1-Phenylsulfonylallenes possessing a hexynyl appendage in refluxing toluene in the presence of catalytic amount of rhodium(I) catalyst under
a carbon monoxide atmosphere underwent regioselective formal [2 + 2 + 1]-cycloaddition to produce the corresponding bicyclo[5.3.0]dec-
1,7-dien-9-one derivatives in acceptable yields.
The Co2(CO)8-mediated Pauson-Khand reaction (PKR) is
a formal [2 + 2 + 1]-cyclization of an alkene, an alkyne,
and carbon monoxide moieties.1 The intramolecular version
of this intriguing cyclization has been well recognized as
one of the most powerful and reliable tools for constructing
cyclopentenone-fused bicyclic derivatives. Thus, both bicyclo-
[3.3.0]octenone 1 and bicyclo[4.3.0]nonenone 2 frameworks2
can be efficiently synthesized from the corresponding enyne
derivatives. In sharp contrast, the application of this intramo-
lecular Co2(CO)8-mediated PKR to the synthesis of bicyclo-
[5.3.0]decenone derivatives 32e,3 has not yet been realized,
except for the synthesis of azabicyclo[5.3.0]decenone deriva-
tives4 and medium-sized oxabicyclic compounds5,6 from
enynes with an aromatic ring as a template. On the other
hand, the alkyne derivative 4 with an allenyl functionality7-10
(3) A bicyclo[5.3.0]decenone framework with an oxygen-bridged
structure was constructed in 29% yield by the zirconocene-mediated PKR.
See: Wender, P. A.; McDonald, F. E. Tetrahedron Lett. 1990, 31, 3691.
However, this structure can be regarded as an oxabicyclo[4.3.0]nonenone
skeleton. In addition, an attempt at Co2(CO)8-mediated PKR was unsuc-
cessful.
(4) Pe´rez-Serrano, L.; Casarrubios, L.; Dom´ınguez, G.; Pe´rez-Castells,
J. J. Chem. Soc., Chem. Commun. 2001, 2602.
(5) (a) Kraft, M. E.; Fu, Z.; Bon˜aga, V. R. Tetrahedron Lett. 2001, 42,
1427. (b) Lovely, C. J.; Seshadri, H.; Wayland, B. R.; Cordes, A. W. Org.
Lett. 2001, 3, 2607.
(1) For leading reviews, see: (a) Schore, N. E. Org. React. 1991, 40, 1.
(b) Schore, N. E. In ComprehensiVe Organic Synthesis; Trost, B. M., Ed.;
Pergamon: Oxford, 1991; Vol. 5, p 1037. (c) Fru¨hauf, H.-W. Chem. ReV.
1997, 97, 523. (d) Jeong, N. Transition Met. Org. Synth. 1998, 1, 560. (e)
Geis, O.; Schmalz, H.-G. Angew. Chem., Int. Ed. 1998, 37, 911. (f)
Brummond, K. M.; Kent, J. L. Tetrahedron 2000, 56, 3263.
(2) (a) Mukai, C.; Uchiyama, M.; Sakamoto, S.; Hanaoka, M. Tetrahe-
dron Lett. 1995, 36, 5761. (b) Mukai, C.; Kim, J. S.; Uchiyama, M.;
Sakamoto, S. Hanaoka, M. J. Chem. Soc., Perkin Trans. 1 1998, 2903. (c)
Mukai, C.; Kim, J. S.; Uchiyama, M.; Hanaoka, M. Tetrahedron Lett. 1998,
39, 7909. (d) Mukai, C.; Kim, J. S.; Sonobe, H.; Hanaoka, M. J. Org. Chem.
1999, 64, 6822. (e) Mukai, C.; Sonobe, H.; Kim, J. S.; Hanaoka, M. J.
Org. Chem. 2000, 65, 6654.
(6) Zr-mediated PKR for the preparation of medium-sized rings with an
aromatic ring was also reported. Barluenga, J.; Sanz, R.; Fan˜ana´s, F. J.
Chem. Eur. J. 1997, 3, 1324.
(7) Co-mediated PKR of alleynes: (a) Ahmar, M.; Antras, F.; Cazes, B.
Tetrahedron Lett. 1995, 36, 4417. (b) Ahmar, M.; Chabanis, O.; Gauthier,
J.; Cazes, B. Tetrahedron Lett. 1997, 38, 5277. (c) Ahmar, M.; Locatelli,
C.; Colombier, D.; Cazes B. Tetrahedron Lett. 1997, 38, 5281. (d)
10.1021/ol020051w CCC: $22.00 © 2002 American Chemical Society
Published on Web 04/17/2002

instead of an olefin group produced the bicyclo[5.3.0]dec-
1,7-dien-9-one 57c under Co2(CO)8-mediated PKR conditions,
although the chemical yields were rather low (10-25%). Fe-
(CO)4(NMe3)9 was also found to promote the Pauson-
Khand-type [2 + 2 + 1]-cyclization of an allenyne 6,
resulting in the formation of the bicyclo[5.3.0]dec-1,7-dien-
9-one derivative 7 in 15% yield (Scheme 1).
propargyl alcohols and chemical transformation of these
sulfur-containing groups to other functionalities was already
reported. This Letter deals with our preliminary results
regarding the efficient rhodium(I)-catalyzed PKR of al-
lenynes14 for the construction of 2-phenylsulfonylbicyclo-
[5.3.0]dec-1,7-dien-9-one derivatives.
The simple precursors 11 for the cyclization in this
investigation were readily prepared from 5-hexyn-1-ol (7)
(Scheme 2). Protection of the acetylenic terminus of 7 with
Scheme 1
Scheme 2a
a Reaction conditions: (a) (i) BuLi, TMSCl, THF, (ii) 10% HCl;
(b) I2, PPh3, imid., CH2Cl2; (c) LiCtCCH2OTBS, THF-DMPU;
(d) 10% HCl, MeOH, 9a (54%), 9b (16%); (e) TBAF, THF, (96%);
(f) Phl, PdCl2(PPh3)2, iPr2NH, CuI, THF, (68%); (g) PhSCl, Et3N,
THF; (h) mCPBA, CH2Cl2, 11a (78%), 11b (69%), 11c (69%).
Many bioactive natural products have a bicyclo[5.3.0]-
decane skeleton11 as a basic carbon framework. Therefore,
the straightforward and efficient preparation of a bicyclo-
[5.3.0]decane ring system under PKR conditions with an
acceptable yield could become an alternative and useful
method for the synthesis of these natural products. Recent
reports from Jeong12 and Narasaka13 independently disclosed
that rhodium(I) catalysts are effective in the PKR of enynes.
To develop a reliable as well as straightforward procedure
for preparing the bicyclo[5.3.0]decane framework by a
Pauson-Khand-type reaction, we sought to combine these
rhodium catalysts with allenyne derivatives. We paid much
attention to allenynes having a sulfinyl or sulfonyl group as
a starting material for this investigation, because these
allenynes could be easily prepared from the corresponding
a silyl group was followed by iodination to give 8. The iodo
compound 8 was then coupled with the acetylide, derived
from the O-protected propargyl alcohol, to afford the diyne
derivative, which was hydrolyzed under acidic conditions
to give 9a in 54% overall yield along with 9b (16%).
Desilylation of 9a was easily performed with TBAF to give
9b in 96% yield. Palladium-mediated Sonogashira coupling15
of 9b with iodobenzene proceeded under standard conditions
to give 9c in 68% yield. The three propargyl alcohols 9a-c
were independently exposed to benzenesulfenyl chloride16
in the presence of Et3N to give the corresponding sulfoxides,
which were directly oxidized with mCPBA to furnish the
allenyl sulfones 11 in yields of 69-78%.
For the initial evaluation of the rhodium-catalyzed PKR
of the resulting allenynes, we first attempted the cyclization
of compound 11b.17 A solution of 11b in toluene was
refluxed in the presence of 5 mol % of [RhCl(CO)2]213 under
an atmosphere of carbon monoxide (condition A) for 1 h to
give the bicyclo[5.3.0]dec-1,7-dien-9-one 12b in 58% yield
as a sole isolable product (Table 1, entry 3). Reducing the
amount of the catalyst to 2.5 mol % in the same reaction
gave a lower yield (41%). When 5 mol % of [RhCl(CO)-
Pagenkopf, B. L.; Belanger, D. B.; O’Mahony, D. J. R.; Livinghouse, T.
Synthesis 2000, 1009. (e) Antras, F.; Ahmar, M.; Cazes, B. Tetrahedron
Lett. 2001, 42, 8153. (f) Antras, F.; Ahmar, M.; Cazes, B. Tetrahedron
Lett. 2001, 42, 8157.
(8) Mo-mediated PKR of alleynes: (a) Kent, J. L.; Wan, H.; Brummond,
K. M. Tetrahedron Lett. 1995, 36, 2407. (b) Brummond, K. M.; Wan, H.
Tetrahedron Lett. 1998, 39, 931. (c) Brummond, K. M.; Wan, H.; Kent, J.
L. J. Org. Chem. 1998, 63, 6535. (d) Brummond, K. M.; Lu, J. J. Am.
Chem. Soc. 1999, 121, 5087. (e) Brummond, K. M.; Lu, J.; Petersen, J. J.
Am. Chem. Soc. 2000, 122, 4915. (f) Xiong, H.; Hsung, R. P.; Wei, L.-L.;
Berry, C. R.; Mulder, J. A.; Stockwell, B. Org. Lett. 2000, 2, 2869.
(9) Fe-mediated PKR of allenynes: Shibata, T.; Koga, Y.; Narasaka, K.
Bull. Chem. Soc. Jpn. 1995, 68, 911.
(10) For Zr-mediated PKR of alleynes, see: refs 8b and 8c
(11) For example: (a) Herz, H.; Santhanam, P. S. J. Org. Chem. 1965,
30, 4340. (b) Lansburg, P. T.; Hangauer, D. G., Jr.; Vacca, J. P. J. Am.
Chem. Soc. 1980, 102, 3964. (c) Heathcock, C. H.; DelMar, E. G.; Graham,
S. L. J. Am. Chem. Soc. 1982, 104, 1907. (d) Grieco, P. A.; Majetich, G.
F.; Ohfune, Y. J. Am. Chem. Soc. 1982, 104, 4226. (e) Heathcock, C. H.;
Tice, C. M.; Germroth, T. C. J. Am. Chem. Soc. 1982, 104, 6081.
(12) (a) Jeong, N.; Lee, S.; Sung, B. K.Organometallics 1998, 17, 3642.
(b) Jeong, N.; Sung, B. K.; Choi, Y. K. J. Am. Chem. Soc. 2000, 122, 6771.
(13) (a) Koga, Y.; Kobayashi, T.; Narasaka, K. Chem. Lett. 1998, 249.
(b) Kobayashi, T.; Koga, Y.; Narasaka, K. J. Organomet. Chem. 2001, 624,
73.
(14) During this investigation, the Rh(I)-catalyzed PKR of an allenyne
leading to formation of the bicyclo[4.3.0]non-1,6-dien-8-one derivative in
61% yield was reported. See ref 13b.
(15) Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron Lett. 1975,
4467.
(16) Horner, L.; Binder, V. Ann. Chem. 1972, 37, 757.
(17) Rh(I)-catalyzed PKR of the sulfoxide derivative 10b was examined
under conditions A and B; however, no reaction took place and the starting
sulfoxide was completely recovered intact.
1756
Org. Lett., Vol. 4, No. 10, 2002

Scheme 3a
Table 1. Ring Closure of Allenes 1
entry allene
R
condition mol % product yield (%)
1
2
3
4
5
6
11a
11a
11b
11b
11c
11c
TMS
TMS
H
H
Ph
A
B
A
B
A
B
5
5
5
5
2.5
2.5
12a
12a
12b
12b
12c
12c
45
7a
58b
75c
51
a Reaction conditions: (a) NaH, ICH2CtCCH2OTBDPS, THF;
(b) TBAF, THF, (80%); (c) Phl, PdCl2(PPh3)2, iPr2NH, CuI, THF,
15b (82%), 17b (95%); (d) PhSCl, Et3N, THF; (e) mCPBA, CH2Cl2,
16a (78%), 16b (80%), 18a (77%), 18b (80%); (f) NaH, DMF,
I(CH2)2CtCCH2OTHP; (g) NaH, BrCH2CtCH, THF; (h) p-TsOH,
MeOH, (56%).
Ph
84
a The starting material 11b was recovered in 45% yield. b The cyclized
product 12b was obtained in 41% yield when 2.5 mol % of [RhCl(CO)2]2
was used. c The cyclized product 12b was obtained in 56% yield when 2.5
mol % of [RhCl(CO)dppp]2 was used.
to produce the bicyclo[5.3.0]dec-1,7-dien-9-one derivatives
17a,b in good yields. A similar result was observed when
alleynes 18a,b were exposed to conditions A and B, although
the yields with the latter compounds seemed to be somewhat
lower. The results are shown in Table 2.
12
dppp]2 (condition B) was used instead of [RhCl(CO)2]2,
the ring-closed product 12b was formed in a higher yield
(75%, entry 4). Similar treatment of the phenyl derivative
11c under both conditions A and B gave the corresponding
bicyclo[5.3.0]dec-1,7-dien-9-one 12c in respective yields of
51% and 84% (entries 5 and 6). Upon exposure to condition
A, 11a gave 12a in 45% yield (entry 1). However, condition
B gave 12a in only 7% yield along with recovery of the
starting material 11a in 45% yield (entry 2). These results
are summarized in Table 1. Several points deserve comment.
(i) The bicyclo[5.3.0] skeleton was constructed in acceptable
yields compared to those in previous works.7c,9 (ii) Complete
chemoselectivity was observed in the formal [2 + 2 +
1]-cycloaddition, leading to the exclusive construction of the
bicyclo[5.3.0]dec-1,7-dien-9-one framework 12, while the
corresponding bicyclo[4.3.0]nonenone derivative 13 was not
detected in the reaction mixture.
Our next step was to see whether conditions A and B could
be applied to other allenynes. Therefore, we investigated the
rhodium-catalyzed PKR of four additional alleynes 16a,b
and 18a,b. The allenynes required for the cyclization were
prepared as depicted in Scheme 3. Treatment of the malonate
14 with the iodobutyne derivative was followed by desily-
lation to give 15a in 80% yield. According to the procedure
described for the transformation of 9 into 11, 15a was easily
converted through [2,3]-sigmatropic rearrangement16 to the
corresponding alleyne 16a in 78% yield. The Sonogashira
coupling15 of 15a with iodobenzene produced 15b, which
was subsequently converted to the phenyl congener 16b. The
two other starting allenynes 18a,b could also be easily
obtained from dimethyl malonate by conventional means
(Scheme 3).
Table 2. Ring Closure of Allene 16 and 18
entry allene
R
condition mol % product yield (%)
1
2
3
4
5
6
7
8
16a
16a
16b
16b
18a
18a
18b
18b
H
H
Ph
Ph
H
H
Ph
Ph
A
B
A
B
A
B
A
B
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
19a
19a
19b
19b
20a
20a
20b
20b
84
70
70
71
58
59
40
69
The rhodium-catalyzed PKR of two allenynes 16a,b
proceeded under both two conditions A and B as expected
We next examined the PKR of the enyne derivative 21
by applying conditions A and B, which effectively catalyzed
Org. Lett., Vol. 4, No. 10, 2002
1757

dppp]2) depending on the starting allenyne. The application
of this rhodium-catalyzed PKR of allenynes to the construc-
tion of other ring systems, such as the bicyclo[6.3.0]undec-
1,8-dien-10-one framework, is now in progress.
Scheme 4
Acknowledgment. We wish to thank Professor Nakcheol
Jeong, Korea University, Korea, for useful discussions on
the rhodium(I) catalyst.
the PKR of allenynes. Thus, a solution of 21 in toluene was
refluxed for a long time in the presence of catalytic amounts
of rhodium catalyst under a carbon monoxide atmosphere.
However, no cyclized product 22 could be detected in the
reaction mixture, and the starting material 21 was completely
recovered intact.
In summary, we have developed a reliable procedure for
constructing a bicyclo[5.3.0]decane ring system by the
rhodium-catalyzed PKR of allenynes with a sulfonyl group.18
Acceptable yields could be achieved through the proper
choice of the rhodium catalyst ([RhCl(CO)2]2 or [RhCl(CO)-
Supporting Information Available: Experimental pro-
cedures for ring closure and preparation of compound 16a
1
and spectral data and H and 13C NMR spectra for 11a-c,
12a-c, 16a,b, 18a,b, 19a,b, and 20a,b. This material is
available free of charge via the Internet at http://pubs.acs.org.
OL020051W
(18) Preliminary experiments revealed that the compound having a
diethylphosphono group [PO(OEt)2] at the C-1 position of an allenyl moiety
instead of a sulfonyl group (e.g., 16a), upon exposure to the Rh(I)-catalyzed
cyclization conditions, produced the corresponding bicyclo[5.3.0]dec-1,7-
dien-9-one skeleton. The details of these results will be reported later.
1758
Org. Lett., Vol. 4, No. 10, 2002