Rhodium Complex-Catalyzed Cycloisomerization of Allenenes: Exo and Endo Cyclization Depending on the Auxiliary Ligands

Article abstract of DOI:10.1021/jo035551x

In the presence of a catalytic amount of a rhodium(I) complex, allenenes undergo cycloisomerization reactions resulting in the selective formation of exo-alkylidenecarbocycles and heterocycles. In the catalytic system of rhodium complexes with triaryl phosphites, cyclic 1,4- or 1,5-dienes are formed in good to excellent yields in the formal exo-cyclization mode via the metallacycle intermediate having an exo-alkylidene moiety. In this cycloisomerization, (E)- and (Z)-allenenes are transformed stereospecifically to the corresponding cyclic (E)- and (Z)-1,4-dienes, respectively. On the other hand, the reactions under carbon monoxide atmosphere exclusively afford seven-membered-ring products through an endo-mode cyclization. The unusual cyclization involves an allylic C-H activation process. The allenene bearing a silicon substituent at the olefinic terminus incorporates carbon monoxide to give the corresponding [2+2+1] cycloaddition product. This result apparently indicates that the catalysis of the rhodium complex is explained in terms of the oxidative cyclization of an allenene to furnish the key exo-alkylidene metallacycle intermediate at the first stage of the catalysis.

Full text of DOI:10.1021/jo035551x

Rh od iu m Com p lex-Ca ta lyzed Cycloisom er iza tion of Allen en es:
Exo a n d En d o Cycliza tion Dep en d in g on th e Au xilia r y Liga n d s
Tatsuya Makino and Kenji Itoh*
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University,
Chikusa, Nagoya 464-8603, J apan
itohk@apchem.nagoya-u.ac.jp
Received October 20, 2003
In the presence of a catalytic amount of a rhodium(I) complex, allenenes undergo cycloisomerization
reactions resulting in the selective formation of exo-alkylidenecarbocycles and heterocycles. In the
catalytic system of rhodium complexes with triaryl phosphites, cyclic 1,4- or 1,5-dienes are formed
in good to excellent yields in the formal exo-cyclization mode via the metallacycle intermediate
having an exo-alkylidene moiety. In this cycloisomerization, (E)- and (Z)-allenenes are transformed
stereospecifically to the corresponding cyclic (E)- and (Z)-1,4-dienes, respectively. On the other hand,
the reactions under carbon monoxide atmosphere exclusively afford seven-membered-ring products
through an endo-mode cyclization. The unusual cyclization involves an allylic C-H activation
process. The allenene bearing a silicon substituent at the olefinic terminus incorporates carbon
monoxide to give the corresponding [2+2+1] cycloaddition product. This result apparently indicates
that the catalysis of the rhodium complex is explained in terms of the oxidative cyclization of an
allenene to furnish the key exo-alkylidene metallacycle intermediate at the first stage of the catalysis.
In tr od u ction
Ru,5 Rh,6 Ir,7 Ni-Cr,8 Pd,9,10 and Pt5g). It was revealed
that a stoichiometric amount of cobalt11 and nickel12
complexes promoted such enyne cycloisomerizations.
Similarly, transition metal-catalyzed cycloisomerizations
of 1,n-dienes have also been widely investigated (Sc,13
Ti,14 Zr,15 Ta,16 Ru,17 Rh,18 Ni,19 and Pd20).
Though interesting and useful transformations of
allenes had been known,21 allenes still received less
attention as a component for the catalytic formation of
carbon-carbon multiple bonds compared with alkynes
and alkenes. In the past decade, the transition metal-
catalyzed reaction of allenes has been noticed as an
important carbon-carbon and carbon-heteroatom bond-
forming process, since it exhibited high chemo-, regio-,
and stereoselectivity. In particular, several palladium
complexes have been employed for a wide range of
Carbocycles and heterocycles are extremely important
and basic skeletons in many biologically active natural
products with several complex structures. Thus the
development of effective methods for the construction of
ring systems has been the subject of extensive investiga-
tion. Increasing social needs for environmentally friendly
chemical processes call for the transition metal complex-
catalyzed carbocyclization of alkynes and alkenes as
valuable and powerful protocols for the preparation of a
wide range of carbocycles or heterocycles with high
efficiency and selectivity.1 Above all, transition metal-
catalyzed cycloisomerization reactions are atom economi-
cal and environmentally benign synthetic processes
because there is no requirement of additional reactants
excepting catalysts and solvents.2,3 Especially, the active
development of the catalytic cycloisomerization reaction
of 1,n-enynes has been achieved, and various transition
metal complexes have been reported to be efficient (Ti,4
(5) (a) Nishida, M.; Adachi, N.; Onozuka, K.; Matsumura, H.; Mori,
M. J . Org. Chem. 1998, 63, 9158-9159. (b) Mori, M.; Kozawa, Y.;
Nishida, M.; Kanamaru, M.; Onozuka, K.; Takimoto, M. Org. Lett.
2000, 2, 3245-3247. (c) Trost, B. M.; Toste, F. D. J . Am. Chem. Soc.
1999, 121, 9728-9729. (d) Trost, B. M.; Toste, F. D. J . Am. Chem. Soc.
2000, 122, 714-715. (e) Trost, B. M.; Toste, F. D. J . Am. Chem. Soc.
2002, 124, 5025-5036. (f) Le Paih, J .; Rodr´ıguez, D. C.; De´rien, S.;
Dixneuf, P. H. Synlett 2000, 95-97. (g) Me´ndez, M.; Mun˜oz, M. P.;
Nevado, C.; Ca´rdenas, D. J .; Echavarren, A. M. J . Am. Chem. Soc.
2001, 123, 10511-10520.
* To whom correspondence should be addressed. Phone: +81-52-
789-5112. Fax: +81-52-789-3205.
(1) (a) Lautens, M.; Klute, W.; Tam, W. Chem. Rev. 1996, 96, 49-
92. (b) Negishi, E.; Cope´ret, C.; Ma, S.; Liou, S.-Y.; Liu, F. Chem. Rev.
1996, 96, 365-393. (c) Ojima, I.; Tzamarioudaki, M.; Li, Z.; Donovan,
R. Chem. Rev. 1996, 96, 635-662. (d) Mori, M. Top. Organomet. Chem.
1998, 1, 133-154. (e) Aubert, C.; Buisine, O.; Malacria, M. Chem. Rev.
2002, 102, 813-834. (f) Trost, B. M.; Toste, D. F.; Pinkerton, A. B.
Chem. Rev. 2002, 101, 2067-2096.
(6) (a) Cao, P.; Wang, B.; Zhang, X. J . Am. Chem. Soc. 2000, 122,
6490-6491. (b) Cao, P.; Zhang, X. Angew. Chem., Int. Ed. 2000, 39,
4104-4106. (c) Lei, A.; He, M.; Zhang, X. J . Am. Chem. Soc. 2002,
124, 8198-8199. (d) Lei, A.; He, M.; Wu, S.; Zhang, X. Angew. Chem.,
Int. Ed. 2002, 41, 3457-3460. (e) Lei, A.; Waldkirch, J . P.; He, M.;
Zhang, X. Angew. Chem., Int. Ed. 2002, 41, 4526-4529. (f) Lei, A.;
He, M.; Zhang, X. J . Am. Chem. Soc. 2002, 124, 8198-8199. (g) Tong,
X.; Zhang, Z.; Zhang, X. J . Am. Chem. Soc. 2003, 125, 6370-6371.
(7) Chatani, N.; Inoue, H.; Morimoto, T.; Muto, T.; Murai, S. J . Org.
Chem. 2001, 66, 4433-4436.
(2) Trost, B. M.; Krische, M. J . Synlett 1998, 1-16.
(3) For reviews on transition metal-catalyzed atom economical
reactions, see: (a) Trost, B. M. Science 1991, 254, 1471-1477. (b) Trost,
B. M. Angew. Chem., Int. Ed. Engl. 1995, 34, 259-281. (c) Trost, B.
M. Chem. Eur. J . 1998, 4, 2405-2412. (d) Trost, B. M. Acc. Chem.
Res. 2002, 35, 695-705.
(4) Sturla, S. J .; Kablaoui, N. M.; Buchwald, S. L. J . Am. Chem.
Soc. 1999, 121, 1976-1977.
(8) Trost, B. M.; Tour, J . M. J . Am. Chem. Soc. 1987, 109, 5268-
5270.
10.1021/jo035551x CCC: $27.50 © 2004 American Chemical Society
Published on Web 12/24/2003
J . Org. Chem. 2004, 69, 395-405
395

Makino and Itoh
transition metal catalysis of allenes.22 There are generally
two methodologies to approach the desired products. One
is the addition of carbon or heteroatom nucleophiles to
the allene moiety, which is activated by coordinative
interaction with transition metal complexes.22c-f The
other depends on carbometalation and oxidative cycliza-
tion of an allene functionality.22d,e,23-26 Especially, a
number of quests have been made for catalytic carbony-
lative cycloaddition reactions,27 such as the intramolecu-
lar allenic Pauson-Khand reaction, i.e., the [2+2+1]
cycloaddition of allenynes,28-31 according to the latter
concept.
Catalytic cycloisomerizations of allenes also have been
under current investigation. For example, Brummond et
(19) (a) Bodoganovic, B. Adv. Organomet. Chem. 1979, 17, 105-140.
(b) Behr, A.; Freudenberg, U.; Keim, W. J . Mol. Catal. 1986, 35, 9-17.
(c) Radetich, B.; RajanBabu, T. V. J . Am. Chem. Soc. 1998, 120, 8007-
8008. (d) Walther, D.; Do¨hler, T.; Heubach, K.; Klobes, O.; Schweder,
B.; Go¨rls, H. Z. Anorg. Allg. Chem. 1999, 625, 923-932.
(20) (a) Grigg, R.; Mitchell, T. R. B.; Ramasubbu, A. J . Chem. Soc.,
Chem. Commun. 1979, 669-670. (b) Heumann, A.; Moukhliss, M.
Synlett 1998, 1211-1212. (c) Widenhoefer, R. A.; Perch, N. S. Org.
Lett. 1999, 1, 1103-1105. (d) Kisanga, P.; Widenhoefer, R. A. J . Am.
Chem. Soc. 2000, 122, 10017-10026. (e) Kisanga, P.; Goj, L. A.;
Widenhoefer, R. A. J . Org. Chem. 2001, 66, 635-637. (f) Goj, L. A.;
Widenhoefer, R. A. J . Am. Chem. Soc. 2001, 123, 11133-11147. (g)
Bray, K. L.; Fairlamb, I. J . S.; Lloyd-J ones, G. C. Chem. Commun 2001,
187-188. (h) Bray, K. L.; Charmant, J . P. H.; Fairlamb, I. J . S.; Lloyd-
J ones, G. C. Chem. Eur. J . 2001, 7, 4205-4215. (i) Oh, C. H.; Kim, J .
D.; Han, J . W. Chem. Lett. 2001, 1290-1291 and also see refs 18b,c,e
and 19c.
(21) (a) Patai, S. The Chemistry of Ketenes, Allenes and Related
Compunds; Wiley: Chichester, UK, 1980. (b) Landor, S. R. The
Chemistry of Allenes; Academic Press: London, UK, 1982. (c) Schuster,
H. F.; Coppola, G. M. Allenes in Organic Synthesis; Wiley: New York,
1984. (d) Pasto, D. J . Tetrahedron 1984, 40, 2805-2827. (e) Zimmer,
R. Synthesis 1993, 165-178. (f) Zimmer, R.; Khan, F. A. J . Prakt.
Chem. 1996, 338, 92-94.
(22) (a) Grigg, R.; Sridharan, V. Pure Appl. Chem. 1998, 338, 1047-
1057. (b) Lautens, M.; Rovis, T.; Smith, N. D.; Ostrovsky, D. Pure Appl.
Chem. 1998, 338, 1059-1064. (c) Yamamoto, Y.; Radhakrishnan, U.
Chem. Soc. Rev. 1999, 28, 199-207. (d) Zimmer, R.; Dinesh, C. U.;
Nandanan, E.; Khan, F. A. Chem. Rev. 2000, 100, 3067-3125. (e)
Hashmi, A. S. K. Angew. Chem., Int. Ed. 2000, 39, 3590-3593. (f)
Bates, R. W.; Satcharoen, V. Chem. Soc. Rev. 2002, 31, 12-21. (f) Ma,
S. Acc. Chem. Res. 2003, 36, 701-712.
(23) For leading papers on the late transition metal-catalyzed
carbocyclization in the past decade, see: Rh: (a) Kang, S.-K.; Hong,
Y.-T.; Lee, J .-H.; Kim, W.-Y.; Lee, I.; Yu, C.-M. Org. Lett. 2003, 5, 2813-
2816. Ni: (b) Montgomery, J .; Song, M. Org. Lett. 2002, 4, 4009-4011.
(c) Kang, S.-K.; Yoon, S.-K. Chem. Commun. 2002, 2634-2635. Pd:
(d) Ma, S.; Negishi, E. J . Org. Chem. 1994, 59, 4730-4732. (e) Ma, S.;
Negishi, E. J . Am. Chem. Soc. 1995, 117, 6345-6357. (f) Doi, T.;
Yanagisawa, A.; Nakanishi, S.; Yamamoto, K.; Takahashi, T. J . Org.
Chem. 1996, 61, 2062-2063. (g) Doi, T.; Yanagisawa, A.; Yamamoto,
K.; Takahashi, T. Chem. Lett. 1996, 1085-1086. (h) Kang, S.-K.; Baik,
T.-G.; Kulak, A. N.; Ha, Y.-H.; Lim, Y.; Park, J . J . Am. Chem. Soc.
2000, 122, 11529-11530. (i) Kang, S.-K.; Ha, Y.-H.; Ko, B.-S.; Lim,
Y.; J ung, J . Angew. Chem., Int. Ed. 2002, 41, 343-345. (j) Kang, S.-
K.; Lee, S.-W.; J ung, J .; Lim, Y. J . Org. Chem. 2002, 67, 4376-4379.
(k) Ha, Y.-H.; Kang, S.-K. Org. Lett. 2002, 4, 1143-1146. (l) Gai, X.;
Grigg, R.; Collard, S.; Muir, J . E. Chem. Commun. 2000, 1765-1766.
(m) Lo¨fstedt, J .; Franze´n, J .; Ba¨ckvall, J .-E. J . Org. Chem. 2001, 66,
8015-8025. (n) Franze´n, J .; Lo¨fstedt, J .; Dorange, I.; Ba¨ckvall, J .-E.
J . Am. Chem. Soc. 2002, 124, 11246-11247. (o) Franze´n, J .; Ba¨ckvall,
J .-E. J . Am. Chem. Soc. 2003, 125, 6056-6057. (p) Lo¨fstedt, J .; Na¨rhi,
K.; Dorange, I.; Ba¨ckvall, J .-E. J . Org. Chem. 2003, 68, 7243-7248.
(q) Shin, S.; RajanBabu, T. V. J . Am. Chem. Soc. 2001, 123, 8416-
8417. (r) Ohno, H.; Miyamura, K.; Takeoka, Y.; Tanaka, T. Angew.
Chem., Int. Ed. 2003, 42, 2647-2650 and references therein.
(24) For leading papers on early transition metal-mediated carbocy-
clization in recent years, see: (a) Urabe, H.; Takeda, T.; Hideura, D.;
Sato, F. J . Am. Chem. Soc. 1997, 119, 11295-11305. (b) Urabe, H.;
Sato, F. Tetrahedron Lett. 1998, 39, 7329-7332. (c) Sato, F.; Urabe,
H.; Okamoto, S. Synlett 2000, 753-775 and references therein.
(25) For catalytic intramolecular cycloadditions, see the following.
[3+2], Rh: (a) Hayashi, M.; Ohmatsu, T.; Meng, Y.-P.; Saigo, K. Angew.
Chem., Int. Ed. 1998, 37, 837-839. [4+2], Rh and Ni: (b) Wender, P.
A.; J enkins, T. E.; Suzuki, S. J . Am. Chem. Soc. 1995, 117, 1843-
1844. [5+2], Rh: (c) Wender, P. A.; Glorius, F.; Husfeld, C. O.;
Langkopf, E.; Love, J . A. J . Am. Chem. Soc. 1999, 121, 5348-5349.
Wender and co-workers also applied the rhodium-catalyzed reaction
to total syntheses of natural products, see: (d) Wender, P. A.; Fuji,
M.; Husfeld, C. O.; Love, J . A. Org. Lett. 1999, 1, 137-139. (e) Wender,
P. A.; Zhang, L. Org. Lett. 2000, 2, 2323-2326. (f) Wender, P. A.; Bi,
F. C.; Gamber, G. G.; Gosselin, F.; Hubbard, R. D.; Scanio, M. J . C.;
Sun, R.; Williams, T. J .; Zhang, L. Pure Appl. Chem. 2002, 74, 25-31.
Cf. for the stoichiometric [2+2] cycloaddition with molybdenum
complexes, see: (g) Shen, Q.; Hammond, G. B. J . Am. Chem. Soc. 2002,
124, 6534-6535.
(9) (a) Trost, B. M.; Lautens, M. J . Am. Chem. Soc. 1985, 107, 1781-
1783. (b) Trost, B. M.; Lautens, M. Tetrahedron Lett. 1985, 26, 4887-
4890. (c) Trost, B. M.; Chen, S.-F. J . Am. Chem. Soc. 1986, 108, 6053-
6054. (d) Trost, B. M.; Lee, D. C.; Rise, F. Tetrahedron Lett. 1989, 30,
651-654. (e) Trost, B. M.; Lee, D. C. J . Org. Chem. 1989, 54, 2271-
2274. (f) Trost, B. M.; Edstrom, E. D.; Carter-Petillo, M. B. J . Org.
Chem. 1989, 54, 4489-4490. (g) Trost, B. M.; Lautens, M.; Chan, C.;
J ebaratnam, D. J .; Mueller, T. J . Am. Chem. Soc. 1991, 113, 636-
644. (h) Trost, B. M.; Pedregal, C. J . Am. Chem. Soc. 1992, 114, 7292-
7294. (i) Trost, B. M.; Gelling, O. J . Tetrahedron Lett. 1993, 34, 8233-
8236. (j) Trost, B. M.; Czeskis, B. A. Tetrahedron Lett. 1994, 35, 211-
214. (k) Trost, B. M.; Tanoury, G. J.; Lautens, M.; Chan, C.; MacPherson,
D. T. J . Am. Chem. Soc. 1994, 116, 4255-4267. (l) Trost, B. M.; Romero,
D. L.; Rise, F. J . Am. Chem. Soc. 1994, 116, 4268-4278. (m) Goeke,
A.; Sawamura, M.; Kuwano, R.; Ito, Y. Angew. Chem., Int. Ed. Engl.
1996, 35, 662-663. (n) Yamada, H.; Aoyagi, S.; Kibayashi, C. Tetra-
hedron Lett 1997, 38, 3027-3030. (o) Hatano, M.; Terada, M.; Mikami,
K. Angew. Chem., Int. Ed. 2001, 40, 249-253. (p) Hatano, M.; Mikami,
K. J . Mol. Catal. A 2003, 196, 165-169. (q) Hatano, M.; Mikami, K. J .
Am. Chem. Soc. 2003, 125, 4704-4705. (r) Hatano, M.; Yamanaka,
M.; Mikami, K. Eur. J . Org. Chem. 2003, 2552-2555.
(10) For applications to total syntheses of natural products, see: (a)
Trost, B. M.; Chung, J . Y. L. J . Am. Chem. Soc. 1985, 107, 4586-
4588. (b) Trost, B. M.; J ebaratnam, D. J . Tetrahedron Lett. 1987, 28,
1611-1614. (c) Trost, B. M.; Hipskind, P. A.; Chung, J . Y. L.; Chan,
C. Angew. Chem., Int. Ed. Engl. 1989, 28, 1502-1504. (d) Trost, B.
M.; Phan, L. T. Tetrahedron Lett. 1993, 34, 4735-4738. (e) Trost, B.
M.; Krische, M. J . J . Am. Chem. Soc. 1996, 118, 233-234. (f) Trost, B.
M.; Li, Y. J . Am. Chem. Soc. 1996, 118, 6625-6633. (g) Trost, B. M.;
Krische, M. J . J . Am. Chem. Soc. 1999, 121, 6131-6141. (h) Trost, B.
M.; Haffner, C. D.; J ebaratnam, D. J .; Krische, M. J .; Thomas, A. P. J .
Am. Chem. Soc. 1999, 121, 6183-6192. (i) Trost, B. M.; Corte, J . R.;
Gudiksen, M. S. Angew. Chem., Int. Ed. 1999, 38, 3662-3664.
(11) (a) Llerena, D.; Aubert, C.; Malacria, M. Tetrahedron Lett. 1996,
37, 7353-7356. (b) Buisine, O.; Aubert, C.; Malacria, M. Chem. Eur.
J . 2001, 7, 3517-3525. (c) Kagoshima, H.; Hayashi, M.; Hashimoto,
Y.; Saigo, K. Organometallics 1996, 15, 5439-5441. (d) Kraft, M. E.;
Wilson, A. M.; Dasse, O. A.; Bonaga, L. V. R.; Cheung, Y. Y.; Fu, Z.;
Shao, B.; Scott, I. L. Tetrahedron Lett. 1998, 39, 5911-5914. (e)
Dolaine, R.; Gleason, J . L. Org. Lett. 2000, 2, 1753-1756. (f) Ajamian,
A.; Gleason, J . L. Org. Lett. 2001, 3, 4161-4164.
(12) (a) Tamao, K.; Kobayashi, K.; Ito, Y. J . Am. Chem. Soc. 1988,
110, 1286-1288. (b) Tamao, K.; Kobayashi, K.; Ito, Y. Synlett 1992,
539-546.
(13) (a) Bunel, E. E.; Burger, B. J .; Bercaw, J . E. J . Am. Chem. Soc.
1988, 110, 976-978. (b) Piers, W. E.; Shapiro, P. J .; Bunel, E. E.;
Bercaw, J . E. Synlett 1990, 74-84. (c) Piers, W. E.; Bercaw, J . E. J .
Am. Chem. Soc. 1990, 112, 9406-9407.
(14) (a) Akita, M.; Yasuda, H.; Nagasuna, K.; Nakamura, A. Bull.
Chem. Soc. J pn. 1983, 56, 554-558. (b) Lehmkuhl, H.; Tsien, Y.-L.
Chem. Ber. 1983, 116, 2437-2446. (c) Thorn, M. G.; Hill, J . E.;
Waratuke, S. A.; J ohnson, E. S.; Franwick, P. E.; Rothwell, I. P. J .
Am. Chem. Soc. 1997, 119, 8630-8641. (d) Okamoto, S.; Livinghouse,
T. J . Am. Chem. Soc. 2000, 122, 1223-1224. (e) Okamoto, S.;
Livinghouse, T. Organometallics 2000, 19, 1449-1451.
(15) (a) Christoffers, J .; Bergman, R. G. J . Am. Chem. Soc. 1996,
118, 4715-4716. (b) Thiele, S.; Erker, G. Ber./ Recl. 1997, 130, 201-
207. (c) Bazan, G. C.; Rodriguez, G.; Ashe, A. J ., III; Al-Ahmad, S.;
Kampf, J . W. Organometallics 1997, 16, 2492-2494. (d) Schweder, B.;
Walther, D.; Do¨hler, T.; Klobes, O.; Go¨rls, H. J . Prakt. Chem. 1999,
341, 736-747.
(16) (a) McLain, S. J .; Schrock, R. R. J . Am. Chem. Soc. 1978, 100,
1315-1317. (b) Smith, G.; McLain, S. J .; Schrock, R. R. J . Organomet.
Chem. 1980, 202, 269-277.
(17) (a) Yamamoto, Y.; Ohkoshi, N.; Itoh, K. J . Org. Chem. 1999,
64, 2178-2179. (b) Yamamoto, Y.; Nakagai, Y.; Ohkoshi, N.; Itoh, K.
J . Am. Chem. Soc. 2001, 123, 6372-6380.
(18) (a) Bright, A.; Molone, J . F.; Nicholson, J . K.; Powell, J .; Shaw,
B. L. J . Chem. Soc., Chem. Commun. 1971, 712-713. (b) Schmitz, E.;
Urban, R.; Heuck, U.; Zimmermann, G.; Gru¨ndemann, E. J . Prakt.
Chem. 1976, 318, 185-192. (c) Schmitz, E.; Heuck, U.; Habisch, D. J .
Prakt. Chem. 1976, 318, 471-478. (d) Grigg, R.; Mitchell, T. R. B.;
Ramasubbu, A. J . Chem. Soc., Chem. Commun. 1980, 27-28. (e) Grigg,
R.; Malone, J . F.; Mitchell, T. R. B.; Ramasubbu, A.; Scott, R. M. J .
Chem. Soc., Parkin Trans. 1 1984, 1745-1754.
396 J . Org. Chem., Vol. 69, No. 2, 2004

Rh Complex-Catalyzed Cycloisomerization of Allenenes
SCHEME 1
al. and Shibata et al. quite recently reported indepen-
dently that allenynes undergo catalytic cycloisomeriza-
tion to afford cross-conjugated trienes in the presence of
rhodium complexes.32 Moreover, the transition metal-
catalyzed cycloisomerization reaction of allenenes is also
expected to be valuable.33,34 Trost and co-workers re-
ported pioneering studies with nickel-chromium33a and
SCHEME 2
(26) For catalytic intermolecular cycloadditions, see the following.
[2+2], Ni: (a) Saito, S.; Hirayama, K.; Kabuto, C.; Yamamoto, Y. J .
Am. Chem. Soc. 2000, 122, 10776-10780. [3+2], Pd: (b) Meguro, M.;
Yamamoto. Y. J . Org. Chem. 1999, 64, 694-695. [2+2+2], Ni: (c)
Shanmugasundaram, M.; Wu, M.-S.; Cheng, C.-H. Org. Lett. 2001, 3,
4233-4236. (d) Shanmugasundaram, M.; Wu, M.-S.; J eganmohan, M.;
Huang, C.-W.; Cheng, C.-H. J . Org. Chem. 2002, 67, 7724-7729. (e)
Wu, M.-S.; Shanmugasundaram, M.; Cheng, C.-H. Chem. Commun.
2003, 718-719. [4+2], Rh: (f) Murakami, M.; Ubukata, M.; Itami, K.;
Ito, Y. Angew. Chem., Int. Ed. 1998, 37, 2248-2250. [4+2], Pd: (g)
Siegel, H.; Hopf, H.; Germer, A.; Binger, P. Chem. Ber. 1978, 111,
3112-3118. (h) Murakami, M.; Itami, K.; Ito, Y. J . Am. Chem. Soc.
1997, 119, 7163-7164. (i) Murakami, M.; Minamida, R.; Itami, K.;
Sawamura, M.; Ito, Y. Chem. Commun. 2000, 2293-2294. [4+4], Pd:
(j) Murakami, M.; Itami, K.; Ito, Y. Synlett 1999, 951-953.
(27) [2+2+1], Ru: (a) Kang, S.-K.; Kim, K.-J .; Hong, Y.-T. Angew.
Chem., Int. Ed. 2002, 41, 1584-1586. [4+1], Fe: (b) Eaton, B. E.;
Rollman, B.; Kaduk, J . A. J . Am. Chem. Soc. 1992, 114, 6245-6246.
(c) Sigman, M. S.; Kerr, C. E.; Eaton, B. E. J . Am. Chem. Soc. 1993,
115, 7545-7546. (d) Sigman, M. S.; Eaton, B. E. J . Org. Chem. 1994,
59, 7488-7491. (e) Sigman, M. S.; Eaton, B. E. J . Am. Chem. Soc. 1996,
118, 11783-11788. [4+1], Rh and Pt: (f) Murakami, M.; Itami, K.;
Ito, Y. Angew. Chem., Int. Ed. Engl. 1995, 34, 2691-2694. (g)
Murakami, M.; Itami, K.; Ito, Y. J . Am. Chem. Soc. 1996, 118, 11672-
11673. (h) Murakami, M.; Itami, K.; Ito, Y. J . Am. Chem. Soc. 1997,
119, 2950-2951. (i) Murakami, M.; Itami, K.; Ito, Y. J . Am. Chem.
Soc. 1999, 121, 4130-4135. (j) Murakami, M.; Itami, K.; Ito, Y.
Organometallics 1999, 18, 1326-1336. [4+1], Pd: (k) Mandai, T.; Tsuji,
J .; Tsujiguchi, Y.; Saito, S. J . Am. Chem. Soc. 1993, 115, 5865-5866.
(l) Darcel, C.; Bruneau, C.; Dixneuf, P. H. Synlett 1996, 218-220. [5+1],
Ir: (m) Murakami, M.; Itami, K.; Ubukata, M.; Tsuji, I.; Ito, Y. J . Org.
Chem. 1998, 63, 4-5. [4+4+1], Pd: (n) Murakami, M.; Itami, K.; Ito,
Y. Angew. Chem., Int. Ed. 1998, 37, 3418-3420.
(28) Ti: (a) Hicks, F. A.; Kablaoui, N. M.; Buchwald, S. L. J . Am.
Chem. Soc. 1996, 118, 9450-9451. (b) Hicks, F. A.; Kablaoui, N. M.;
Buchwald, S. L. J . Am. Chem. Soc. 1999, 121, 5881-5898. Rh: (c)
Kobayashi, T.; Koga, Y.; Narasaka, K. J . Organomet. Chem. 2001, 624,
73-87. (d) Brummond, K. M.; Still, P. C.; Rickards, B.; Geib, S. J .
Tetrahedron Lett. 2002, 43, 3735-3738. (e) Brummond, K. M.; Chen,
H.; Fisher, K. D.; Kerekes, A. D.; Rickards, B.; Still, P. C.; Geib, S. J .
Org. Lett. 2002, 4, 1931-1934. (f) Brummond, K. M.; Gao, D. Org. Lett.
2003, 5, 3491-3494. (g) Mukai, C.; Nomura, I.; Yamanishi, K.;
Hanaoka, M. Org. Lett. 2002, 4, 1755-1758. (h) Mukai, C.; Nomura,
I.; Kitagaki, S. J . Org. Chem. 2002, 68, 1376-1385. Ir: (i) Shibata,
T.; Kadowaki, S.; Hirase, M.; Kadowaki, S.; Takagi, K. Synlett 2003,
268-270.
(29) For transition metal-promoted [2+2+1] cycloaddition of al-
lenynes, see the following. Mo, Co, and Zr: (a) Kent, J . L.; Wan, H.;
Brummond, K. M. Tetrahedron Lett. 1995, 36, 2407-2410. (b) Brum-
mond, K. M.; Wan, H. 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. M.; Kerekes, A. D.; Wan, H. J . Org. Chem.
2002, 67, 5156-5163. Co: (e) Ahmar, M.; Locatelli, C.; Colombier, D.;
Cazes, B. Tetrahedron Lett. 1997, 38, 5281-5284. Brummond and co-
workers applied the molybdenum-mediated reaction to total syntheses
of natural products, see: (f) Brummond, K. M.; Lu, J . J . Am. Chem.
Soc. 1999, 121, 5087-5088. (g) Brummond, K. M.; Lu, J .; Peterson, J .
J . Am. Chem. Soc. 2000, 122, 4915-4920.
palladium33b catalysts. Recently, Kang et al. employed
ruthenium catalysts in the cycloisomerization of alle-
nenes to cyclic 1,3-dienes or 1,4-dienes.33c
Herein, we wish to report the rhodium(I)-catalyzed
cycloisomerization of allenenes with high efficiency and
selectivity by way of the participation of the internal
allenic π-bond to generate corresponding carbocycles and
heterocycles (Scheme 1).35 It should be noted that the
present cyclization proceeds via formal exo- or endo-mode
cyclization pathways in striking dependence on the
auxiliary ligands.
Resu lts a n d Discu ssion
Cycloisom er iza tion of Allen en es Lea d in g to F ive-
Mem ber ed Rin gs. We first examined the reaction of
allenene 1 in the presence of a catalytic amount of [RhCl-
(cod)]2 (2.5 mol %, cod ) 1,5-cyclooctadiene) and P(OPh)3
(Rh/P ) 1/2) in toluene at 110 °C and obtained an
encouraging result, i.e., the cyclic 1,4-diene 2 processing
the exo-methylene moiety was isolated in 77% yield with
85% purity as the cycloisomerization product (Scheme
2).36 The rhodium complex was essential to this trans-
formation; no reaction occurred without the rhodium
catalyst under the identical conditions. To optimize
reaction conditions, a series of experiments was under-
taken with allenene 1 as a model substrate to find the
best reaction conditions, e.g., solvents and catalysts
(Table 1). The effect of additives will be discussed in
detail later (vide infra). While the cycloisomerization
proceeded in di-n-butyl ether, isolated yields and selectiv-
ity decreased to some extent (entry 2). Highly efficient
conversions of 1 into 2 were observed in 1,4-dioxane and
chlorobenzene (entries 3 and 4). Particularly, the former
afforded the best result on both a product yield and
selectivity. This result suggests that the coordination of
the rhodium center to 1,4-dioxane gives a stabilizing
(30) It was also disclosed that a stoichiometric amount of the cobalt
complex promoted the intermolecular allenic Pauson-Khand reaction,
see: (a) Ahmar, M.; Antras, F.; Cazes, B. Tetrahedron Lett. 1995, 36,
4417-4420. (b) Ahmar, M.; Chabanis, O.; Gauthier, J .; Cazes, B.
Tetrahedron Lett. 1997, 38, 5277-5280.
(31) For recent reviews on Pauson-Khand reactions, see: (a) Geis,
O.; Schmalz, H.-G. Angew. Chem., Int. Ed. 1998, 37, 911-914. (b)
Chung, Y. K. Coord. Chem. Rev. 1999, 188, 297-341. (c) Brummond,
K. M.; Kent, J . L. Tetrahedron 2000, 56, 3263-3283. (d) Fletcher, A.
J .; Christie, S. D. R. J . Chem. Soc., Perkin Trans. 1 2000, 1657-1668.
(e) Gibson, S. E.; Stevenazzi, A. Angew. Chem., Int. Ed. 2003, 42, 1800-
1810.
(33) (a) Trost, B. M.; Tour, J . M. J . Am. Chem. Soc. 1988, 110, 5231-
5233. (b) Trost, B. M.; Matsuda, K. J . Am. Chem. Soc. 1988, 110, 5233-
5235. (c) Kang, S.-K.; Ko, B.-S.; Lee, D.-M. Tetrahedron Lett. 2002,
43, 6693-6696.
(34) Previously, Trost et al. investigated the related ruthenium-
catalyzed intermolecular couplings of allenes and alkenes derived from
vinyl ketones to provide 1,3-dienes, see: (a) Trost, B. M.; Pinkerton,
A. B. J . Am. Chem. Soc. 1999, 121, 4068-4069. (b) Trost, B. M.;
Pinkerton, A. B.; Kremzow, D. J . Am. Chem. Soc. 2001, 123, 12466-
12476.
(32) (a) Brummond, K. M.; Chen, H.; Sill, P.; You, L. J . Am. Chem.
Soc. 2002, 124, 15186-15187. (b) Shibata, T.; Takesue, Y.; Kadowaki,
S.; Takagi, K. Synlett 2003, 268-270. Cf. for the cobalt-mediated
cycloisomerization of allenynes, see: (c) Llerena, D.; Aubert, C.;
Malacria, M. Tetrahedron Lett 1996, 37, 7027-7030.
(35) For a preliminary communication, see: Makino, T.; Itoh, K.
Tetrahedron Lett. 2003, 44, 6335-6338.
(36) The conversion and the purity were determined by GC analysis
of the reaction mixture and the isolated product 2, respectively. The
recovered allenene 1 was included in the impurity.
J . Org. Chem, Vol. 69, No. 2, 2004 397

Makino and Itoh
TABLE 1. Effect of Solven ts a n d Ca ta lysts on
Cycloisom er iza tion of Allen en e 1a
CHART 1
time yield purity
entry
catalyst (mol %)
solvent
toluene
n-Bu2O
1,4-dioxane
PhCl
(h)
(%)b
(%)c
1
2
3
4
5
6
7
8
9
[RhCl(cod)]2 (2.5)
[RhCl(cod)]2 (2.5)
[RhCl(cod)]2 (2.5)
[RhCl(cod)]2 (2.5)
[RhCl(cod)]2 (2.5)
[RhCl(coe2)]2 (2.5) 1,4-dioxane
[RhCl(CO)2]2 (2.5) 1,4-dioxane
[Rh(cod)2]PF6 (5)
18
18
12
14
24
12
14
24
24
77
62
92
81
26
77
87
87
31
85
74
95
90
53
89
90
85
59
DMF
rial (Chart 1). There might have been steric interaction
between the tert-butyldimethylsilyloxy group and the
coordinated phosphite ligands to retard the requisite
coordination of the rhodium center to 11 for cyclization.
We then investigated the influence of substituents at the
alkene moiety of allenenes. The (E)-allenenes E-12 bear-
ing a trimethylsilyl group at the alkene terminus were
subjected to smooth cycloisomerization to provide only
the corresponding (E)-1,4-dienes E-13 (entry 6). In a
similar manner, the phenyl-substituted (E)-allenenes
E-14 were exclusively converted into E-15 (entry 7). On
the other hand, the cyclization of its stereoisomer Z-14
(E/Z ) 1/56.2) achieved the selective formation of the
corresponding cyclic product Z-15 in excellent yield (E/Z
) 1/21.9, entry 8). These results indicate that the present
cycloisomerization proceeds with high stereospecificity.
The respective stereochemistry of E-13, E-15, and Z-15
was unambiguously confirmed by the observation of
appreciable NOE correlations as depicted in Figure 1.
1,4-dioxane
Rh(acac)(CO)2 (5) 1,4-dioxane
a
All reactions were carried out with Rh complexes and P(OPh)3
(Rh/P ) 1/2) at 110 °C (bath temperature) under Ar atmosphere.
Isolated yield. c Determined by GC analyses.
b
effect on the catalytic active species. On the other hand,
N,N-dimethylformamide (DMF) was an improper solvent
and a large quantity of undesirable isomers and oligo-
mers were formed (entry 5). In addition to [RhCl(cod)]2,
other rhodium(I) complexes bearing bridged chloride
ligands such as [RhCl(coe)2]2 (coe ) cyclooctene) and
[RhCl(CO)2]2 were also effective catalysts (entries 6 and
7). A cationic complex [Rh(cod)2]PF6 was also acceptable
(entry 8), whereas Rh(acac)(CO)2 (acac ) acetylacetonato)
resulted in a striking decrease in the isolated yield and
the purity of 2 (entry 9). Furthermore, other rhodium
complexes, a rhodium(0) complex Rh4(CO)12 and a rhod-
ium(III) complex [Cp*RhCl2]2, provided no expected
product 2 but a complex mixture of unidentified oligo-
mers. A rhodium(II) complex [Rh(OAc)2]2 exhibited no
catalytic activity. The above observation indicates that
1,4-dioxane and [RhCl(cod)]2 are the best choice of solvent
and catalyst combination, respectively. It is notable that
the analogous iridium(I) complex [IrCl(cod)]2 also fur-
nished the cycloisomerization product 2 under identical
conditions despite much lower efficiency and selectivity
(51% yield with 82% purity).
The results obtained for other allenenes under the
optimum conditions are shown in Table 2. Further
investigations revealed that the more bulky phosphite
ligand P(O-o-tol)3 improved the selectivity of cycloisomer-
izations to raise the purity of the cyclization products
(entry 1). The reaction of the barbituric acid derivative
3 provided a spiro-ring product 4 (entry 2). Allenene 5
derived from tosylamide cycloisomerized favorably to
afford pyrrolidine derivative 6 despite somewhat low
selectivity (entry 3),37 whereas the benzylamine deriva-
tive 7, which contains a more electron-rich nitrogen atom,
resulted in a significant decrease in the yield of the
desired product 8 (entry 4). Similarly, the oxygen-
tethered allenene 9 gave the tetrahydrofuran derivative
10 in poor yield concomitant with inseparable isomers
(entry 5). In both reactions, unidentified oligomers were
formed. We presumed that the strong coordination of
electron-rich heteroatoms of 7 and 9 forced the orienta-
tion of the allene and the alkene in an anti conformation,
which was unsuitable for the desirable cyclizations.
Unfortunately, allenene 11, which has a bulky substitu-
ent, tert-butyldimethylsilyloxy, hardly underwent cyclo-
isomerization, resulting in the recovery of starting mate-
F IGURE 1. NOE correlations for E-13, E-15, and Z-15.
Interestingly, the analogous allenene 16 with a methyl
group at the terminal position of the alkene moiety
showed characteristic behavior (Table 3). In contrast to
the cycloisomerizations described above, the reaction of
allenene 16 (E/Z ) 3/1) exclusively afforded cyclic 1,5-
diene 17 instead of the 1,4-diene as a mixture of diaster-
eomers with preferential formation of the cis isomer (cis/
trans ) 2.8/1, entry 1). The phosphite P(O-o-PhC6H4)3,
more bulky than P(O-o-tol)3, was not effective in the
improvement of the stereoselectivity (entry 2). The fact
that a similar distribution of diastereomers was obtained
in the reaction of E-16 apparently indicates that there
is no correlation between the geometry of the alkene
moiety in 16 and the stereochemistry of cyclic 1,5-diene
17 (entry 3). The stereochemistry of 17 was assigned on
the basis of the value of the H-H coupling constant
between a pair of the protons at the ring junctures (J )
7.5 Hz). Furthermore, Figure 2 compares the 13C NMR
spectral data for the major product and that for the minor
product, that is, the signal for the carbon neighboring
the stereocenter appears at a higher field by steric
compression of a gauche interaction in the cis isomer
relative to the trans isomer in 13C NMR spectra.38
The attempted cyclization of an allenene with a gem-
disubstituted alkene such as 18 completely failed and the
(37) Almost pure 6 was readily obtained by recrystallization from
ethyl acetate/n-hexane.
(38) Siverstein, R. M.; Webster, F. X. Spectrometric Identification
of Organic Compounds, 6th ed.; Wiley: New York, 1998.
398 J . Org. Chem., Vol. 69, No. 2, 2004

Rh Complex-Catalyzed Cycloisomerization of Allenenes
TABLE 2. Rh -Ca ta lyzed Cycloisom er iza tion of Allen en esa
a
All reactions were carried out with [RhCl(cod)]2 and P(O-o-tol)3 (Rh/P ) 1/2) in 1,4-dioxane at 110 °C (bath temperature) under Ar
atmosphere. E ) CO2Me. Isolated yield. c Determined by GC analyses.
b
TABLE 3. Cycloisom er iza tion s of Allen en e 16
F IGURE 2. Selected data for 13C NMR spectra of cis- and
trans-17.
E/Z ratio
of 16
time yield purity cis/trans
entry
P(OAr)3
(h) (%)a (%)b ratio of 17b
1
2
3
3/1
3/1
30/1
P(O-o-tol)3
P(O-o-PhC6H4)3 24
P(O-o-PhC6H4)3 24
20
90
93
91
87
93
91
2.8/1
3/1
2.8/1
containing a trisubstituted alkene also resulted in no
reaction due to the inhibition of its coordination by the
steric congestion of the alkene moiety (Chart 1).
a
b
Isolated yield. Determined by GC analyses.
Furthermore, we explored the tolerance of the allenic
moiety toward these catalytic cyclizations (Table 4). Even
allenene 20, possessing the parent allenyl moiety, readily
underwent cycloisomerization despite the low yield of the
corresponding product 21 (entry 1). The employment of
P(O-o-PhC6H4)3 improved both the yield and the purity
starting material remained intact (Chart 1). This sug-
gests that the existence of a hydrogen atom at the
internal olefinic position is necessary to cycloisomeriza-
tion leading to 1,5-dienes (vide infra). Allenene 19
J . Org. Chem, Vol. 69, No. 2, 2004 399

Makino and Itoh
TABLE 4. Effect of Su bstitu en ts a t th e Allen e Moietya
a
All reactions were carried out with [RhCl(cod)]2 and P(OAr)3 (Rh/P ) 1/2) in 1,4-dioxane at 110 °C (bath temperature) under Ar
atmosphere. E ) CO2Me. Isolated yield. c Determined by GC analyses.
b
SCHEME 3
of 21 (entry 2). We assumed that the steric vacancy of
the allene moiety promoted side reactions such as a
catalytic dimerization of allenes.39 The reaction of 22 with
only one alkyl substituent at the allenic terminus pro-
vided the cyclic 1,4-diene 23 as an E/Z mixture with
predominant formation of the E isomer (E/Z ) 2.6/1,
entry 3). The geometry was accurately determined by the
SCHEME 4
values of the H-H coupling constants of vinylic protons
(E-23: J ) 15.3 Hz; Z-23: J ) 10.8 Hz). The change of
the ligand to P(O-o-PhC6H4)3 somewhat improved the
stereoselectivity (E/Z ) 5.4/1, entry 4). In the cyclization
of 24, which has the more bulky tert-butyl group, the
stereoselectivity lowered in comparison with the case
of 22 (E/Z ) 1.5/1, entry 5), whereas the reaction with
P(O-o-PhC6H4)3 enhanced the E/Z ratio of 25 up to 8.3/1
(entry 6). Each geometric isomer of 25 was unambigu-
ously determined in a similar manner (E-25: J ) 15.5
Hz; Z-25: J ) 11.5 Hz).
It is noteworthy that the cycloisomerization of even one
carbon homologated allenene such as 26 selectively
provided the corresponding exo-methylenecyclohexane 27
without the undesirable isomerization of the C-C double
bonds while high loading of the rhodium catalyst was
necessary for complete consumption of 26 (Scheme 3).
It is particularly important that no hydride sources
were required for the present cycloisomerizations. As a
consequence, the cyclization should proceed via a met-
mechanism for the rhodium-catalyzed cycloisomerization
allacycle intermediate generated by an oxidative cycliza-
of allenenes is shown in Scheme 4. The initial step is the
tion mechanism33b rather than via hydrometalation of
coordination of the allenene with a mononuclear rhod-
metal-hydride species followed by a sequence of carbo-
ium(I) phosphite complex, which was generated by the
reaction of [RhCl(cod)]2 with 2 equiv of triaryl phosphites
metalation and â-hydrogen elimination.33a,c A plausible
in situ, at the internal allenic π-bond to lead to the
(39) For recent examples, see the following. Pd: (a) Arisawa, M.;
Sugihara, T.; Yamaguchi, M. Chem. Commun. 1998, 2615-2616. (b)
Oh, C. H.; Yoo, H. S.; J ung, S. H. Chem. Lett. 2001, 1288-1289.
400 J . Org. Chem., Vol. 69, No. 2, 2004
formation of complex 29.40 Subsequently, the oxidative
cyclization gave rhodacyclopentane(III) 30 possessing the

Rh Complex-Catalyzed Cycloisomerization of Allenenes
reaction.42 The central sp carbon of the allene moiety
causes characteristic reactivity toward oxidative cycliza-
tion to give metallacycle 30.
SCHEME 5
Cycloisom er ization of Allen en es Leadin g to Seven -
Mem ber ed Rin gs. During the quests for the optimiza-
tion of conditions of the cycloisomerization of allenene
1, Wilkinson complex RhCl(PPh3)3 was found to cause a
drastic change in the reaction pathway, i.e., the unex-
pected seven-membered-ring product 34 was obtained as
the major product via an unusual endo-mode cyclization
albeit in low isolated yield (Scheme 8).43 This result
apparently indicates that the mode of cyclizations de-
pends on the electronic and steric nature of the ancillary
ligands. Thus, the effect of ligands on formation of a
seven-membered ring was immediately investigated.
Although a full range of phosphine ligands, including
bidentate phosphines, was examined, the desirable prod-
uct 34 was obtained only in moderate yields along with
unidentified isomers. Further studies revealed that the
carbonyl complex [RhCl(CO)2]2 behaved as an effective
catalyst leading to exclusive formation of 34 in 70% yield
without additives (Scheme 9), whereas a similar reaction
with [RhCl(cod)]2 afforded 34 in poor yield (33%). This
result implies that the carbonyl ligands on the rhodium
center are quite important to the selective endo-mode
cyclization.44 Strong support for this presumption is that
the identical reaction under a carbon monoxide atmos-
phere raised the yield of 34 to 80% (Scheme 9). Similarly,
the tosylamide derivatives 5 underwent very rapid cy-
clization to give cyclic enamide 35 in 82% yield. It is also
noteworthy that allenene 18, which was an improper
substrate for formation of five-membered rings, smoothly
affords the corresponding seven-membered-ring 36 in
91% yield (Scheme 10). Unfortunately, other allenenes
such as 3, 7, 9, 14, and 22 did not induce these endo-
mode cyclizations.
exo-alkylidene moiety. Then, metallacycle 30 undergoes
selective elimination of the â-hydrogen atom at the
bridgehead position derived from vinylic hydrogen (Hb)
to give a hydride vinyl complex 31, which spontaneously
induces reductive elimination to furnish the 1,4-diene
product. Presumably, the elimination of the â-hydrogen
derived from the allenic hydrogen (Ha) is disfavored due
to the existence of the sp2 carbon at the R position of the
metallacycle intermediate 30, because the Rh-C-C-Ha
moiety cannot take the coplanar conformation required
for such a â-hydrogen elimination.
The stereospecificity, as shown in the cycloisomeriza-
tion of allenenes 12 and 14, is attributed to a coplanar
arrangement of Rh-C-C-Hb in the abstraction step of
the â-hydrogen Hb. The specific generation of 1,5-diene
17 from methyl-substituted allenene 16 is explained by
a mechanism depicted in Scheme 5. In rhodacycle 30, Hc
of the methyl group is more feasible for smooth â-hydro-
gen elimination than Hb at the ring juncture. Considering
that the kinetic product cis-17 formed predominantly in
each reaction of 16 as shown in Table 3, the oxidative
cyclization seems to be rate determining.
Next, we will discuss the stereoselectivity in the
cyclizations of allenenes 22 and 24 having only one alkyl
substituent at the allenic terminus (Table 4). As il-
lustrated in Scheme 6, the formation of the Z isomer is
anticipated to be more favorable with respect to the steric
repulsion between the substituent R and the rhodium
moiety. Nevertheless, the formation of the less favored
E isomer took place preferentially over the Z isomer in
both cases in 22 and 24.41 It is remarkable that the more
bulky ligand P(O-o-PhC6H4)3 promoted the formation of
the E isomer. In striking contrast to this, excellent
stereoselection was achieved in the [4+1] cycloaddition
of vinylallenes27f,j and the [5+2] cycloaddition of allene-
vinylcyclopropanes,25c which might proceed via analogous
mechanisms. The reason for the predominant formation
of the sterically disfavored E isomer is not clear currently;
however, steric repulsion may not be as significant in the
allenene complex intermediate syn-29.
Two plausible mechanisms for the formation of seven-
membered rings are shown in Scheme 11. Path a involves
a sequence of an allylic C-H activation and carbometa-
lation with the central carbon atom of the allene followed
by reductive elimination.43 The other path is triggered
by intramolecular nucleophilic attack of the alkene
moiety to the coordinated allene in 38 (path b). The
validity of path b was, however, discarded by the follow-
ing experiments. Attempts to capture cationic intermedi-
ate 38 with D2O or EtOD45 completely failed to produce
the expected hydroxy- or ethoxy-substituted products,
and only furnished the ordinal seven-membered-ring
product. In addition, no reaction occurred in the presence
of other electrophilic transition metal catalysts such as
Pt(II), which is widely known as an effective catalyst for
It should be noted that the analogous 1,6-diene 33
never reacted and remained intact under identical condi-
tions (Scheme 7). This observation indicates that the
allene moiety plays a key role in the cycloisomerization
(42) Similar observations were reported in the rhodium- and
platinum-catalyzed [4+1] cycloaddition of vinylallenes and the iridium-
catalyzed [5+1] cycloaddition of allenylcyclopropanes, see refs 27f,j,k.
(43) Recently, Trost et al. reported the formation of exo-alkyl-
idenecycloheptenes by the ruthenium-catalyzed cycloisomerization of
1,6-enynes, see refs 5c,e.
(40) In the case of the rhodium-catalyzed cycloisomerization of
allenynes, the allene moiety coordinates to the rhodium(I) center at
the external allenic π-bond to form the metallacycle intermediate, see
refs 32a,b.
(41) No isomerization of the Z isomer to the more thermodynami-
cally stable E isomer was observed under the reaction conditions.
(44) Under a carbon monoxide atmosphere, even [RhCl(cod)]2 be-
haved as an effective catalyst to give 34 in 74% yield.
(45) (a) Me´ndez, M.; Mun˜oz, M. P.; Echavarren, A. M. J . Am. Chem.
Soc. 2000, 122, 11549-11550. (b) Me´ndez, M.; Mun˜oz, M. P.; Nevado,
C.; Ca´rdenas, D. J .; Echavarren, A. M. J . Am. Chem. Soc. 2001, 123,
10511-10520.
J . Org. Chem, Vol. 69, No. 2, 2004 401

Makino and Itoh
SCHEME 6
SCHEME 7
SCHEME 11
SCHEME 8
SCHEME 9
SCHEME 12
SCHEME 10
the possibility of another reaction pathway cannot be
completely excluded.
In striking contrast to the above, a similar reaction of
trimethylsilyl-substituted allenene E-12 incorporated
carbon monoxide to afford the unprecedented [2+2+1]
cycloaddition product trans,cis-39 concomitant with its
desilylation product trans-4047 as a single stereoisomer,
respectively (Scheme 12).48 A higher CO pressure im-
proved the efficiency of incorporation of carbon monox-
ide.49 The formation of [2+2+1] cycloaddition products
trans,cis-39 and trans-40 is ascribed to the enhanced
stabilization of the metallacycle intermediate 30 in
Scheme 4 by the silicon substituent at an R position to
the rhodium(III) metal. We presume that the rate-
determining CO insertion into metallacycle 30 allows
analogous cyclization of enynes.45b,46 Unfortunately, we
cannot currently give a sufficient account of the unfitness
of several allenenes for the endo-mode cyclizations even
employing the mechanism depicted in Scheme 11. The
substituents might retard the appropriate conformation
required for the allylic C-H activation. Needless to say,
(47) Desilylation of R-silyl ketone trans,cis-39 might proceed via the
corresponding enol silyl ether under thermal or catalytic condition to
provide trans-40, see: Matsuda, I.; Sato, S.; Hattori, M.; Izumi, Y.
Tetrahedron Lett. 1985, 26, 3215-3218.
(46) (a) Chatani, N.; Furukawa, N.; Sakurai, H.; Murai, S. Orga-
nometallics 1996, 15, 901-903. (b) Fu¨rstner, A.; Szillat, H.; Gabor,
B.; Mynott, R. J . Am. Chem. Soc. 1998, 120, 8305-8314. (c) Fu¨rstner,
A.; Szillat, H.; Stelzer, F. J . Am. Chem. Soc. 2000, 122, 6785-6786.
(d) Fu¨rstner, A.; Stelzer, F.; Szillat, H. J . Am. Chem. Soc. 2001, 123,
11863-11869. (e) Oi, S.; Tsukamoto, I.; Miyano, S.; Inoue, Y. Orga-
nometallics 2001, 20, 3704-3709.
(48) The stereochemistry for both trans,cis-39 and trans-40 was
estimated from the NOESY spectra, respectively.
(49) More increase of CO pressure inhibited incorporation of carbon
monoxide to give undesirable isomers.
402 J . Org. Chem., Vol. 69, No. 2, 2004

Rh Complex-Catalyzed Cycloisomerization of Allenenes
(ddd, J ) 1.3, 1.5, 9.0 Hz, 1H) ppm; 13C NMR (125 MHz, CDCl3)
δ 18.2, 25.7, 28.8, 29.0, 42.2, 43.0, 45.2, 55.1, 106.9, 124.6,
134.5, 151.25, 151.34, 172.1, 172.5 ppm; MS (FAB) m/z (rel
intensity, %) 169 (98), 221 (100), 277 (MH+, 100); HRMS (FAB)
calcd for C15H20N2O3 276.1474, found 276.1455.
excellent stereoselection in the [2+2+1] cycloaddition to
furnish thermodynamically stable isomers trans,cis-39
and trans-40 exclusively.
Con clu sion
3-Meth ylen e-4-(2-m eth yl-1-p r op en yl)-1-(4-m eth ylben -
zn esu lfon yl)p yr r olid in e (6). White solid; Rf 0.38 (n-hexane/
ethyl acetate ) 5/1); mp 110-111 °C; IR (CHCl3) ν 815 (m),
900 (m), 1058 (m), 1095 (s), 1161 (vs), 1209 (m), 1345 (s), 1454
(w), 1598 (w), 1666 (w), 2855 (w), 2917 (w), 2974 (w), 3029 (m)
We have found that rhodium(I) triaryl phosphite
complexes effectively catalyzed cycloisomerization of al-
lenenes to produce a variety of carbocycles and hetero-
cycles. In the present transformation, the ligands played
a key role and dominated the cyclization mode. For
example, the reaction of triaryl phosphites exclusively
afforded five-membered rings in the formal exo-cyclic
mode via a metallacycle intermediate with an exo-
alkylidene moiety. On the other hand, the reaction under
a carbon monoxide atmosphere resulted in the selective
formation of seven-membered rings by way of an allylic
C-H activation process. We also found that the similar
reaction of the allenene bearing a silicon substituent gave
the [2+2+1] cycloaddition product as the result of
incorporation of carbon monoxide.
1
cm-1; H NMR (500 MHz, CDCl3) δ 1.60 (s, 3H), 1.69 (s, 3H),
2.43 (s, 3H), 2.62 (dd, J ) 8.9, 9.0 Hz, 1H), 3.41 (ddd, J ) 8.4,
8.7, 9.0 Hz, 1H), 3.63 (dd, J ) 8.4, 9.0 Hz, 1H), 3.65 (ddt, J )
2.0, 2.0, 14.3 Hz, 1H), 4.04 (dd, J ) 1.3, 14.3 Hz, 1H), 4.75-
4.77 (m, 1H), 4.77-4.80 (m, 1H), 4.86-4.88 (m, 1H), 7.33 (d,
J ) 8.3 Hz, 2H), 7.70 (d, J ) 8.3 Hz, 2H) ppm; 13C NMR (125
MHz, CDCl3) δ 18.1, 21.5, 25.6, 42.5, 51.8, 53.5, 107.1, 121.7,
127.8, 129.6, 132.7, 136.0, 143.6, 147.5 ppm; MS (FAB) m/z
(rel intensity, %) 292 (MH+, 100); HRMS (FAB) calcd for
C
16H21O2NS 291.1293, found 291.1327.
1-Ben zyl-3-m eth ylen e-4-(2-m eth yl-1-p r op en yl)p yr r oli-
d in e (8). Colorless oil; Rf 0.42 (n-hexane/ethyl acetate ) 5/1);
IR (neat) ν 881 (s), 973 (w), 1028 (w), 1074 (w), 1126 (m), 1300
(m), 1333 (w), 1374 (m), 1453 (s), 1495 (m), 1663 (m), 2785
(vs), 2912 (vs), 2966 (s), 3028 (m), 3063 (m) cm-1 1H NMR
;
Exp er im en ta l Section
(500 MHz, CDCl3) δ 1.67 (d, J ) 1.5 Hz, 3H), 1.73 (d, J ) 1.5
Hz, 3H), 2.16 (dd, J ) 8.8, 9.5 Hz, 1H), 3.01 (br d, J ) 13.8
Hz, 1H), 3.09 (dd, J ) 7.5, 8.8 Hz, 1H), 3.53-3.60 (m, 1H),
3.57 (d, J ) 13.8 Hz, 1H), 3.60 (d, J ) 12.5 Hz, 1H), 3.71 (d,
J ) 12.5 Hz, 1H), 4.75-4.77 (m, 1H), 4.87-4.89 (m, 1H), 5.00-
Gen er a l P r oced u r e for Rh od iu m (I)-Ca ta lyzed Cyclo-
isom er iza t ion of Allen en es w it h Tr ia r yl P h osp h it e
Liga n d s. To a oven-dried Schlenk flask containing [RhCl-
50
(cod)]2 (3.1 mg, 0.063 mmol) was added a solution of P(O-o-
5.04 (m, 1H), 7.25-7.28 (m, 1H), 7.31-7.38 (m, 4H) ppm; 13
C
51
tol)3 (9.4 mg, 0.027 mmol) in 1,4-dioxane (1 mL). Then a
NMR (125 MHz, CDCl3) δ 18.1, 25.7, 42.9, 58.9, 60.5, 105.5,
124.7, 127.2, 128.3, 129.0, 133.8, 138.1, 151.6 ppm; MS (FAB)
m/z (rel intensity, %) 91 (100), 228 (MH+, 36); HRMS (FAB)
calcd for C16H21N 227.1674, found 227.1665.
solution of dimethyl 2-(4-methyl-2,3-pentadienyl)-2-(2-prope-
nyl)malonate (1) (62.1 mg, 0.25 mmol) in 1,4-dioxane (1.5 mL)
was added to the reaction vessel. The mixture was stirred at
110 °C for 18 h under an Ar atmosphere. After the solution
was cooled to room temperature, the volatile materials were
removed in vacuo. The residue was subjected to silica gel flash
column chromatography (eluent: n-hexane/ethyl acetate ) 20/
1) to afford dimethyl 3-methylene-4-(2-methyl-1-propenyl)-
cyclopentane-1,1-dicarboxylate (2) (56.9 mg, 92%) as a colorless
oil. The gas chromatographic analysis of the isolated product
revealed that 2 was contained in 99% purity.
Dim eth yl 3-Meth ylen e-4-(2-m eth yl-1-p r op en yl)cyclo-
p en ta n e-1,1-d ica r boxyla te (2). Colorless oil; Rf 0.54 (n-
hexane/ethyl acetate ) 5/1); IR (neat) ν 889 (m), 1072 (m), 1173
(m), 1199 (m), 1269 (s), 1376 (w), 1435 (m), 1657 (w), 1737
(vs), 2954 (m) cm-1; 1H NMR (500 MHz, CDCl3) δ 1.64 (d, J )
1.5 Hz, 3H), 1.73 (d, J ) 1.5 Hz, 3H), 1.86 (dd, J ) 11.5, 13.0
Hz, 1H), 2.54 (ddd, J ) 1.3, 7.5, 13.0 Hz, 1H), 2.95 (ddt, J )
2.3, 2.3, 17.0 Hz, 1H), 3.08 (d, J ) 17.0 Hz, 1H), 3.32-3.37
(m, 1H), 3.72 (s, 3H), 3.75 (s, 3H), 4.72-4.74 (m, 1H), 4.88-
4.89 (m, 1H), 4.95-4.97 (m, 1H) ppm; 13C NMR (125 MHz,
CDCl3) δ 18.1, 25.6, 40.0, 40.8, 42.4, 52.7, 52.8, 58.3, 106.9,
125.6, 133.6, 151.3, 172.1, 172.4 ppm; MS (FAB) m/z (rel
intensity, %) 193 (79), 253 (MH+, 100); HRMS (FAB) calcd for
3-Cycloh exylid en em et h yl-4-m et h ylen et et r a h yd r ofu -
r a n (10). Colorless oil; Rf 0.41 (n-hexane/ethyl acetate ) 10/
1); R (neat) ν 849 (w), 887 (m), 930 (m), 967 (w), 1071 (m),
1180 (w), 1232 (w), 1343 (w), 1446 (m), 1665 (w), 1726 (w),
2851 (s), 2927 (vs), 3076 (w) cm-1; 1H NMR (500 MHz, CDCl3)
δ 1.48-1.61 (m, 6H), 2.08-2.17 (m, 4H), 3.38 (dd, J ) 8.0, 9.5
Hz, 1H), 3.51-3.59 (m, 1H), 4.08 (dd, J ) 8.0, 8.0 Hz, 1H),
4.29 (dtt, J ) 2.0, 2.0, 13.4 Hz, 1H), 4.44 (dtt, J ) 1.3, 2.4,
13.4 Hz, 1H), 4.85 (ddd, J ) 2.0, 2.4, 3.0 Hz, 1H), 4.89-4.93
(m, 2H) ppm; 13C NMR (125 MHz, CDCl3) δ 26.8, 28.3, 28.7,
29.3, 37.3, 42.9, 71.4, 74.0, 104.0, 118.9, 143.3, 151.9 ppm; MS
(FAB) m/z (rel intensity, %) 81 (95), 91 (100), 139 (61), 179
(MH+, 47); HRMS (FAB) calcd for C12H19O (MH+) 179.1436,
found 179.1416.
Dim eth yl (E)-3-(2-Meth yl-1-p r op en yl)-4-(tr im eth ylsil-
yl)m eth ylen ecyclop en ta n e-1,1-d ica r boxyla te (E-13). Col-
orless oil; Rf 0.54 (n-hexane/ethyl acetate ) 5/1); IR (neat) ν
840 (s), 959 (m), 1000 (m), 1062 (m), 1100 (m), 1174 (s), 1200
(s), 1249 (s), 1377 (m), 1434 (s), 1625 (m), 1738 (vs), 2953 (vs),
3474 (w) cm-1; 1H NMR (500 MHz, CDCl3) δ 0.08 (s, 9H), 1.62
(d, J ) 1.5 Hz, 3H), 1.70 (d, J ) 1.5 Hz, 3H), 1.81 (dd, J )
11.8, 12.9 Hz, 1H), 2.52 (ddd, J ) 1.8, 7.8, 12.9 Hz, 1H), 2.90
(ddd, J ) 2.5, 2.5, 17.3 Hz, 1H), 3.08 (ddd, J ) 2.5, 2.5, 17.3
Hz, 1H), 3.28-3.34 (m, 1H), 3.72 (s, 3H), 3.74 (s, 3H), 4.90 (d
of sept, J ) 1.5, 9.0 Hz, 1H), 5.20 (ddd, J ) 2.0, 2.5, 2.5 Hz,
1H) ppm; 13C NMR (125 MHz, CDCl3) δ -0.4, 18.1, 25.7, 39.9,
40.1, 45.1, 52.7, 52.8, 58.6, 120.4, 126.0, 133.8, 159.8, 172.2,
172.3 ppm; MS (FAB) m/z (rel intensity, %) 73 (100), 133 (74),
325 (MH+); HRMS (FAB) calcd for C17H29O4Si (MH+) 325.1835,
found 325.1762.
C
14H20O4 252.1362; found 252.1329.
7,8-Dim eth yl-2-m eth ylen e-3-(2-m eth yl-1-p r op en yl)-7,9-
d ia za sp ir o[4.5]d eca n e-6,8,10-tr ion e (4). Pale yellow viscous
oil; Rf 0.33 (n-hexane/ethyl acetate ) 5/1); IR (neat) ν 844 (w),
891 (m), 968 (w), 1004 (w), 1053 (m), 1095 (m), 1148 (w), 1284
(m), 1298 (m), 1326 (m), 1377 (s), 1418 (s), 1455 (s), 1685 (vs),
1747 (m), 2928 (m), 2966 (m), 3078 (w) cm-1 1H NMR (500
;
MHz, CDCl3) δ 1.66 (d, J ) 1.5 Hz, 3H), 1.75 (d, J ) 1.3 Hz,
3H), 2.03 (dd, J ) 11.0, 12.5 Hz, 1H), 2.31 (dd, J ) 8.5, 12.5
Hz, 1H), 2.98 (d, J ) 16.5 Hz, 1H), 3.05 (ddt, J ) 2.3, 2.3, 16.5
Hz, 1H), 3.31 (s, 3H), 3.32 (s, 3H), 3.68-3.75 (m, 1H), 4.80
(ddd, J ) 2.0, 2.3, 2.3 Hz, 1H), 4.93 (d, J ) 2.0 Hz, 1H), 5.01
Dim eth yl (E)-3-Ben zylid en e-4-(2-m eth yl-1-p r op en yl)-
cyclop en ta n e-1,1-d ica r boxyla te (E-15). Colorless oil; Rf
0.46 (n-hexane/ethyl acetate ) 5/1); IR (neat) ν 836 (w), 872
(w), 915 (w), 961 (w), 1063 (m), 1108 (w), 1157 (m), 1200 (s),
1267 (s), 1376 (w), 1434 (m), 1492 (w), 1598 (w), 1736 (vs),
2916 (m), 2952 (m), 3023 (w) cm-1; 1H NMR (500 MHz, CDCl3)
δ 1.72 (d, J ) 1.0 Hz, 3H), 1.81 (d, J ) 1.0 Hz, 3H), 1.87 (dd,
(50) Giordano, G.; Crabtree, R. H. Inorg. Synth. 1979, 19, 218-220.
(51) (a) Kosolapoff, G. M. Organophosphorus Compounds; Wiley:
New York, 1950. (b) Kosolapoff, G. M.; Maier, L. Organic Phosphorus
Compounds; Wiley: New York, 1973; Vol. 5.
J . Org. Chem, Vol. 69, No. 2, 2004 403

Makino and Itoh
J ) 12.5, 12.8 Hz, 1H), 2.60 (ddd, J ) 1.5, 7.0, 12.8 Hz, 1H),
3.23 (ddd, J ) 2.5, 2.5, 18.0 Hz, 1H), 3.42 (d, J ) 18.0 Hz,
1H), 3.55-3.60 (m, 1H), 3.74 (s, 3H), 3.76 (s, 3H), 5.05-5.07
(m, 1H), 6.13 (dt, J ) 2.5, 5.0 Hz, 1H), 7.17-7.21 (m, 1H),
7.29-7.34 (m, 4H) ppm; 13C NMR (125 MHz, CDCl3) δ 18.2,
25.7, 38.6, 40.1, 44.2, 52.7, 52.8, 59.1, 122.7, 125.7, 126.1, 128.2,
134.1, 137.8, 144.2, 172.0, 172.2 ppm; MS (FAB) m/z (rel
intensity, %) 91 (100), 165 (53), 268 (46), 328 (M+, 77); HRMS
(FAB) calcd for C20H24O4 328.1675, found 328.1657.
16.8 Hz, 1H), 3.06-3.11 (m, 1H), 3.71 (s, 3H), 3.73 (s, 3H),
4.78-4.79 (m, 1H), 4.93-4.94 (m, 1H), 5.21 (ddt, J ) 1.4, 8.3,
15.3 Hz, 1H), 5.47 (dt, J ) 7.0, 15.3 Hz, 1H) ppm; 13C NMR
(125 MHz, CDCl3) δ 14.03, 22.47, 29.1, 31.3, 32.4, 40.2, 40.8,
46.7, 52.69, 52.75, 58.3, 107.6, 130.4, 132.8, 151.2, 172.1, 172.2
ppm. Z (minor): 1H NMR (500 MHz, CDCl3) δ 0.87 (t, J ) 7.0
Hz, 3H), 1.23-1.38 (m, 6H), 1.89 (dd, J ) 11.5, 13.0 Hz, 1H),
1.98-2.05 (m, 2H), 2.54 (ddd, J ) 1.5, 7.5, 13.0 Hz, 1H), 2.95
(ddt, J ) 2.3, 2.4, 17.8 Hz, 1H), 3.08 (br d, J ) 17.8 Hz, 1H),
3.42-3.48 (m, 1H), 3.71 (s, 3H), 3.75 (s, 3H), 4.75-4.76 (m,
1H), 4.90-4.91 (m, 1H), 5.17 (ddt, J ) 1.6, 8.9, 10.8 Hz, 1H),
5.50 (ddt, J ) 1.0, 7.5, 10.8 Hz, 1H) ppm; 13C NMR (125 MHz,
CDCl3) δ 14.00, 22.48, 27.4, 29.5, 31.4, 40.1, 40.9, 41.5, 52.72,
52.78, 58.4, 107.3, 130.2, 131.8, 150.9, 172.0, 172.3 ppm.
Dim eth yl 3-(3,3-Dim eth yl-1-bu ten yl-4-m eth ylen ecyclo-
p en ta n e-1,1-d ica r boxyla te (25). Colorless oil; Rf 0.52 (n-
hexane/ethyl acetate ) 5/1); IR (neat) ν 890 (m), 972 (m), 1009
(w), 1072 (m), 1108 (w), 1157 (m), 1173 (m), 1200 (s), 1230 (s),
1252 (s), 1269 (s), 1362 (m), 1435 (m), 1657 (w), 1737 (vs), 2867
(m), 2904 (m), 2954 (s), 3077 (w) cm-1; MS (FAB) m/z (rel
intensity, %) 161 (100), 221 (100), 281 (MH+, 100); HRMS
(FAB) calcd for C16H24O4 280.1675, found 280.1678. E (ma-
jor): 1H NMR (500 MHz, CDCl3) δ 1.00 (s, 9H), 1.96 (dd, J )
11.3, 12.8 Hz, 1H), 2.55 (ddd, J ) 1.5, 7.5, 12.8 Hz, 1H), 2.93
(dddd, J ) 2.0, 2.5, 2.5, 17.0 Hz, 1H), 3.03-3.10 (m, 2H), 3.72
(s, 3H), 3.74 (s, 3H), 4.77 (dddd, J ) 0.8, 2.0, 2.5, 2.5 Hz, 1H),
4.93-4.95 (m, 1H), 5.12 (dd, J ) 8.0, 15.5 Hz, 1H), 5.51 (dd, J
) 1.0, 15.5 Hz, 1H) ppm; 13C NMR (125 MHz, CDCl3) δ 29.7,
32.9, 40.2, 40.9, 46.7, 52.69, 52.8, 58.3, 107.5, 125.1, 143.8,
151.4, 172.1, 172.26 ppm. Z (minor) additional signals: 1H
NMR (500 MHz, CDCl3) δ 1.11 (s, 9H), 1.84 (dd, J ) 11.8, 12.8
Hz, 1H), 2.57 (ddd, J ) 1.0, 7.5, 12.8 Hz, 1H), 2.99 (dddd, J )
2.0, 2.3, 2.5, 17.0 Hz, 1H), 3.03-3.09 (m, 2H), 3.72 (s, 3H),
3.75 (s, 3H), 4.81 (dddd, J ) 0.8, 2.3, 2.5, 2.5 Hz, 1H), 4.93-
4.95 (m, 1H), 4.97 (dd, J ) 10.0, 11.5 Hz, 1H), 5.50 (dd, J )
1.0, 11.5 Hz, 1H) ppm; 13C NMR (125 MHz, CDCl3) δ 31.5,
33.0, 40.0, 41.3, 42.6, 52.73, 107.6, 129.0, 141.8, 151.0, 172.0,
172.31 ppm.
Dim eth yl (Z)-3-Ben zylid en e-4-(2-m eth yl-1-p r op en yl)-
cyclop en ta n e-1,1-d ica r boxyla te (Z-15). Colorless oil; Rf
0.52 (n-hexane/ethyl acetate ) 5/1); IR (neat) ν 698 (m), 755
(m), 840 (w), 891 (w), 916 (w), 965 (w), 1066 (m), 1110 (m),
1202 (s), 1255 (s), 1376 (m), 1434 (s), 1495 (m), 1598 (w), 1731
(vs), 2952 (s), 3023 (m) cm-1 1H NMR (500 MHz, CDCl3) δ
;
1.58 (d, J ) 1.5 Hz, 3H), 1.65 (d, J ) 1.0 Hz, 3H), 1.99 (dd, J
) 6.8, 13.2 Hz, 1H), 2.79 (ddd, J ) 1.6, 8.4, 13.2 Hz, 1H), 3.02
(ddd, J ) 1.5, 1.5, 16.0 Hz, 1H), 3.31 (ddd, J ) 2.3, 2.5, 16.0
Hz, 1H), 3.64-3.70 (m, 1H), 3.736 (s, 3H), 3.737 (s, 3H), 4.94-
4.97 (m, 1H), 6.38-6.40 (m, 1H), 7.12-7.25 (m, 5H) ppm; 13
C
NMR (125 MHz, CDCl3) δ 18.0, 25.3, 39.6, 42.0, 43.5, 52.68,
52.74, 58.1, 123.7, 126.1, 126.9, 127.7, 128.6, 131.8, 137.1,
144.5, 172.0, 172.1 ppm; MS (FAB) m/z (rel intensity, %) 91
(100), 153 (53), 213 (40), 268 (35), 328 (M+, 100). HRMS (FAB)
calcd for C20H24O4 328.1675, found 328.1700.
Dim eth yl 3-(2-Meth yl-1-pr open yl)-4-vin ylcyclopen tan e-
1,1-d ica r boxyla te (17). Colorless oil; Rf 0.53 (n-hexane/ethyl
acetate ) 5/1); IR (neat) ν 859 (w), 915 (m), 995 (m), 1097 (m),
1165 (s), 1197 (s), 1254 (vs), 1377 (m), 1435 (s), 1640 (w), 1732
(vs), 2927 (m), 2952 (s), 3076 (w), 3472 (w) cm-1; MS (FAB)
m/z (rel intensity, %) 207 (96), 235 (60), 267 (MH+, 100); HRMS
(FAB) calcd for C15H23O4 (MH+) 267.1596, found 267.1556. Cis
(major): 1H NMR (500 MHz, CDCl3) δ 1.57 (d, J ) 2.0 Hz,
3H), 1.66 (d, J ) 2.0 Hz, 3H), 2.04 (dd, J ) 7.5, 13.8 Hz, 1H),
2.24 (dd, J ) 7.8, 13.5 Hz, 1H), 2.42 (dd, J ) 7.4, 13.5 Hz,
1H), 2.45 (dd, J ) 7.3, 13.8 Hz, 1H), 2.70 (dddd, J ) 7.4, 7.5,
7.5, 7.8 Hz, 1H), 2.95 (dddd, J ) 7.3, 7.5, 7.5, 9.0 Hz, 1H),
3.71 (s, 3H), 3.72 (s, 3H), 4.89-5.00 (m, 3H), 5.70 (ddd, J )
9.0, 10.5, 17.0 Hz, 1H) ppm; 13C NMR (125 MHz, CDCl3) δ
18.1, 25.8, 38.9, 40.2, 41.6, 47.2, 52.7, 52.8, 59.0, 114.9, 124.2,
132.8, 138.6, 172.9, 173.3 ppm. Trans (minor), additional
signals: 1H NMR (500 MHz, CDCl3) δ 1.58 (d, J ) 2.3 Hz,
3H), 1.67 (d, J ) 2.3 Hz, 3H), 1.99 (dd, J ) 10.5, 13.8 Hz, 1H),
2.51 (dd, J ) 7.8, 13.5 Hz, 1H), 2.54 (dd, J ) 7.0, 10.5 Hz,
3H), 5.65 (ddd, J ) 7.3, 10.3, 17.5 Hz, 1H) ppm; 13C NMR (125
MHz, CDCl3) δ 18.4, 25.7, 39.8, 40.9, 44.6, 50.5, 58.2, 114.8,
125.8, 133.5, 139.4, 173.0, 173.1 ppm.
Dim eth yl 3-Meth ylen e-4-vin ylcyclop en ta n e-1,1-d ica r -
boxyla te (21). Colorless oil; Rf 0.45 (n-hexane/ethyl acetate
) 5/1); IR (neat) ν 821 (w), 892 (m), 918 (m), 992 (w), 1015
(w), 1072 (m), 1109 (w), 1169 (m), 1200 (m), 1269 (m), 1435
(m), 1640 (w), 1658 (w), 1737 (vs), 2953 (m), 2982 (w), 3078
(w) cm-1; 1H NMR (500 MHz, CDCl3) δ 2.01 (dd, J ) 11.0 13.0
Hz, 1H), 2.57 (ddd, J ) 1.5, 7.5, 13.0 Hz, 1H), 2.94 (ddt, J )
2.3, 2.3, 17.0 Hz, 1H), 3.07 (br d, J ) 17.0 Hz, 1H), 3.12-3.18
(m, 1H), 3.72 (s, 3H), 3.74 (s, 3H), 4.82 (q, J ) 2.3 Hz, 1H),
4.98 (q, J ) 2.3 Hz, 1H), 5.05-5.09 (m, 2H), 5.63 (ddd, J )
8.0, 9.5, 17.5 Hz, 1H) ppm; 13C NMR (125 MHz, CDCl3) δ 40.25,
40.27, 47.6, 52.75, 52.82, 58.5, 108.1, 116.1, 139.0, 150.3, 172.0,
172.1 ppm; MS (FAB) m/z (rel intensity, %) 199 (100), 226
(MH2+, 19); HRMS (FAB) calcd for C12H17O4 (MH+) 225.1127,
found 225.1106.
Dim eth yl 4-Meth ylen e-3-(2-m eth yl-1-p r op en yl)cyclo-
h exa n e-1,1-d ica r boxyla te (27). Colorless oil; Rf 0.54 (n-
hexane/ethyl acetate ) 5/1); IR (neat) ν 846 (w), 896 (m), 1011
(w), 1067 (m), 1087 (m), 1159 (s), 1202 (s), 1244 (s), 1292 (m),
1376 (w), 1435 (m), 1646 (m), 1732 (vs), 2952 (s), 3081 (w) cm-1
;
1H NMR (500 MHz, CDCl3) δ 1.52 (dd, J ) 13.0, 13.0 Hz, 1H),
1.58 (d, J ) 1.0 Hz, 3H), 1.73 (d, J ) 1.0 Hz, 3H), 1.77 (ddd,
J ) 4.3, 13.4, 13.4 Hz, 1H), 2.09-2.16 (m, 1H), 2.32-2.42 (m,
3H), 2.96-3.01 (m, 1H), 3.67 (s, 3H), 3.77 (s, 3H), 4.63 (dd, J
) 1.5, 2.0 Hz, 1H), 4.69 (dd, J ) 1.5, 2.0 Hz, 1H), 5.04-5.07
(m, 1H) ppm; 13C NMR (125 MHz, CDCl3) δ 17.9, 25.7, 32.0,
32.3, 38.1, 38.8, 52.5, 52.6, 55.1, 107.3, 125.3, 133.3, 148.3,
171.5, 172.2 ppm; MS (FAB) m/z (rel intensity, %) 147 (100),
207 (100), 267 (MH+, 100); HRMS (FAB) calcd for C15H23O4
(MH+) 267.1596, found 267.1621.
Gen er a l P r oced u r e for Rh od iu m (I)-Ca ta lyzed Cyclo-
isom er iza tion of Allen en es u n d er a Ca r bon Mon oxid e
Atm osp h er e. To a oven-dried Schlenk flask containing [RhCl-
52
(CO)2]2 (2.7 mg, 0.013 mmol) was added 1,4-dioxane (1 mL).
Then a solution of dimethyl 2-(4-methyl-2,3-pentadienyl)-2-
(2-propenyl)malonate (1) (70.6 mg, 0.28 mmol) in 1,4-dioxane
(1.5 mL) was added to the reaction vessel. The system was
charged with CO gas and the resultant mixture was stirred
at 110 °C for 2 h under a CO atmosphere. After the solution
was cooled to room temperature, the volatile materials were
removed in vacuo. The residue was subjected to silica gel flash
column chromatography (eluent; n-hexane/ethyl acetate ) 20/
1) to afford dimethyl 5-isopropylidene-2-cycloheptene-1,1-
dicarboxylate (34) (59.4 mg, 80%) as a colorless oil.
Dim et h yl 3-(1-H ep t en yl)-4-m et h ylen ecyclop en t a n e-
1,1-d ica r boxyla te (23). Colorless oil; Rf 0.50 (n-hexane/ethyl
acetate ) 5/1); IR (CHCl3) ν 890 (m), 968 (w), 1073 (m), 1163
(s), 1200 (s), 1269 (s), 1434 (m), 1656 (w), 1737 (vs), 2855 (m),
2926 (s), 2954 (s) cm-1; MS (FAB) m/z (rel intensity, %) 235
(100), 295 (MH+, 92); HRMS (FAB) calcd for C17H26O4 294.1831,
found 294.1843. E (major): 1H NMR (500 MHz, CDCl3) δ 0.87
(t, J ) 7.0 Hz, 3H), 1.23-1.38 (m, 6H), 1.95 (dd, J ) 11.3,
13.3 Hz, 1H), 1.98-2.05 (m, 2H), 2.53 (ddd, J ) 1.5, 7.6, 12.8
Hz, 1H), 2.92 (ddt, J ) 2.3, 2.5, 16.8 Hz, 1H), 3.06 (br d, J )
Dim eth yl 5-Isop r op ylid en e-2-cycloh ep ten e-1,1-d ica r -
boxyla te (34). Colorless oil; Rf 0.45 (n-hexane/ethyl acetate
(52) McCleverty, J . A.; Wilkinson, G. Inorg. Synth. 1966, 8, 211-
214.
404 J . Org. Chem., Vol. 69, No. 2, 2004

Rh Complex-Catalyzed Cycloisomerization of Allenenes
) 5/1); IR (neat) ν 807 (m), 1066 (s), 1229 (vs), 1373 (m), 1434
(s), 1737 (vs), 2952 (s) cm-1; 1H NMR (500 MHz, CDCl3) δ 1.57
(s, 3H), 1.60 (s, 3H), 2.39 (br s, 4H), 2.85 (d, J ) 6.3 Hz, 2H),
3.70 (s, 6H), 5.64 (dt, J ) 1.5, 10.8 Hz, 1H), 5.95 (dt, J ) 6.3,
10.8 Hz, 1H) ppm; 13C NMR (125 MHz, CDCl3) δ 20.0, 20.3,
27.9, 30.3, 30.6, 52.7, 60.2, 124.8, 126.4, 128.5, 131.8, 171.4
ppm; MS (FAB) m/z (rel intensity, %) 192 (83), 253 (MH+, 100).
Anal. Calcd for C14H20O4: C, 66.65; H, 7.99. Found: C, 66.51;
H, 8.01.
tr a n s,cis-Dim eth yl 4-Isop r op ylid en e-5-oxo-6-(tr im eth -
ylsilyl)h exa h yd r op en ta len e-2,2-d ica r boxyla te (tr a n s,cis-
39). Colorless crystal; mp 130-131 °C; Rf 0.43 (n-hexane/ethyl
acetate ) 5/1); IR (CHCl3) ν 843 (m), 1014 (w), 1067 (w), 1155
(m), 1250 (s), 1268 (s), 1368 (w), 1436 (m), 1636 (m), 1697 (m),
1729 (vs), 2954 (m), 3023 (w) cm-1; 1H NMR (500 MHz, CDCl3)
δ 0.08 (s, 9H), 1.58 (d, J ) 13.0 Hz, 1H), 1.60-1.68 (m, 1H),
1.74 (dd, J ) 12.0, 12.2 Hz, 1H), 1.85 (d, J ) 2.3 Hz, 3H), 1.97
(dd, J ) 12.4, 12.5 Hz, 1H), 2.09 (d, J ) 2.3 Hz, 3H), 2.31-
2.38 (m, 1H), 2.66 (dd, J ) 5.3, 12.2 Hz, 1H), 2.96 (dd, J )
5.8, 12.4 Hz, 1H), 3.737 (s, 3H), 3.739 (s, 3H) ppm; 13C NMR
(125 MHz, CDCl3) δ -2.2, 20.6, 23.7, 37.3, 37.3, 46.1, 47.9,
52.85, 52.86, 54.5, 61.8, 134.3, 143.3, 172.68, 172.70, 209.7
ppm; MS (FAB) m/z (rel intensity, %) 337 (100), 351 (53, M -
H+). Anal. Calcd for C18H28O5Si: C, 61.33; H, 8.01. Found: C,
61.06; H, 7.75.
4-Isop r op ylid en e-1-(4-m eth ylben zen esu lfon yl)-2,3,4,5-
tetr a h yd r o-1H-a zep in e (35). Colorless oil; Rf 0.43 (n-hexane/
ethyl acetate ) 5/1); IR (neat) ν 816 (m), 845 (w), 918 (m), 980
(w), 1018 (m), 1050 (s), 1092 (s), 1163 (vs), 1209 (w), 1291 (m),
1306 (m), 1339 (vs), 1398 (m), 1449 (m), 1494 (w), 1597 (m),
1
1648 (m), 2920 (m) cm-1; H NMR (500 MHz, CDCl3) δ 1.37
(s, 3H), 1.55 (s, 3H), 2.40-2.45 (m, 2H), 2.41 (s, 3H), 2.82 (d,
J ) 5.9 Hz, 2H), 3.70-3.73 (m, 2H), 5.01 (dt, J ) 5.9, 8.9 Hz,
1H), 6.41 (dt, J ) 1.5, 8.9 Hz, 1H), 7.27-7.28 (m, 2H), 7.65-
7.68 (m, 2H) ppm; 13C NMR (125 MHz, CDCl3) δ 19.8, 20.3,
21.4, 28.2, 32.2, 47.1, 111.7, 125.8, 126.7, 127.5, 127.9, 129.5,
137.0, 143.2 ppm; MS (FAB) m/z (rel intensity, %) 292 (MH+,
100); HRMS (FAB) calcd for C16H21NO2S 291.1293, found
291.1286.
tr a n s-Dim eth yl 4-Isop r op ylid en e-5-oxoh exa h yd r op en -
ta len e-2,2-d ica r boxyla te (tr a n s-40). Colorless oil; Rf 0.36
(n-hexane/ethyl acetate ) 3/1); IR (neat) ν 822 (w), 837 (w),
902 (w), 936 (w), 967 (w), 1036 (m), 1065 (m), 1088 (m), 1198
(s), 1263 (s), 1369 (m), 1435 (s), 1624 (s), 1703 (vs), 1731 (vs),
1
2952 (s) cm-1; H NMR (500 MHz, CDCl3) δ 1.87 (d, J ) 1.0
Hz, 3H), 1.92 (dd, J ) 8.5, 13.5 Hz, 1H), 1.97 (dd, J ) 7.8,
13.0 Hz, 1H), 2.20 (d, J ) 1.5 Hz, 3H), 2.21 (dd, J ) 5.0, 18.5
Hz, 1H), 2.58 (dd, J ) 10.0, 18.5 Hz, 1H), 2.64 (ddd, J ) 1.5,
7.8, 13.0 Hz, 1H), 2.59-2.73 (m, 1H), 2.88 (ddd, J ) 1.5, 8.5,
13.5 Hz, 1H), 3.40-3.46 (m, 1H), 3.70 (s, 3H), 3.76 (s, 3H) ppm;
13C NMR (125 MHz, CDCl3) δ 20.6, 24.5, 34.7, 41.07, 41.08,
44.6, 45.4, 52.7, 52.8, 61.6, 135.0, 149.7, 171.7, 172.2, 206.4
ppm; MS (FAB) m/z (rel intensity, %) 217 (62), 249 (54), 281
(100, M+); HRMS (FAB) calcd for C15H20O5 280.1336, found
280.1311.
Dim eth yl 5-Isop r op ylid en e-3-m eth yl-2-cycloh ep ten e-
1,1-d ica r boxyla te (36). Colorless oil; Rf 0.42 (n-hexane/ethyl
acetate ) 5/1); IR (neat) ν 649 (w), 692 (w), 746 (w), 824 (m),
908 (w), 938 (w), 984 (w), 1021 (m), 1067 (m), 1118 (m), 1246
(vs), 1339 (w), 1374 (m), 1434 (s), 1736 (vs), 2727 (w), 2857
(m), 2952 (s) cm-1; 1H NMR (500 MHz, CDCl3) δ 1.57 (s, 3H),
1.62 (s, 3H), 1.84 (d, J ) 1.3 Hz, 3H), 2.33-2.36 (m, 2H), 2.37-
2.40 (m, 2H), 2.80 (s, 2H), 3.69 (s, 6H), 5.37 (d, J ) 1.3 Hz,
1H) ppm; 13C NMR (125 MHz, CDCl3) δ 20.0, 20.4, 27.1, 27.9,
30.6, 35.5, 52.6, 59.5, 120.2, 125.0, 128.0, 140.6, 171.8 ppm;
MS (FAB) m/z (rel intensity, %) 147 (84), 207 (82), 266 (M+,
100); HRMS (FAB) calcd for C15H23O4 (MH+) 267.1596, found
267.1597.
Gen er a l P r oced u r e for Rh od iu m (I)-Ca ta lyzed [2+2+1]
Cycloa d d it ion of Allen en es u n d er Ca r b on Mon oxid e
P r essu r e. A glass tube (27 mm in diameter) placed in a 100
mL stainless steel autoclave was charged with dimethyl (E)-
2-(4-methyl-2,3-pentadienyl)-2-[3-(trimethylsilyl)-2-propenyl]-
malonate (E-12) (84.1 mg, 0.26 mmol), [RhCl(CO)2]2 (2.5 mg,
0.0064 mmol), and 1,4-dioxane (2.5 mL). After the reactor was
flushed with 3 atm of CO three times, it was pressurized with
CO to 3 atm. The contents were stirred at 110 °C for 24 h and
cooled to room temperature. After excess CO was purged, the
volatile materials were removed in vacuo. The residue was
subjected to silica gel flash column chromatography (eluent:
n-hexane/ethyl acetate ) 30/1) to afford trans,cis-dimethyl
4-isopropylidene-5-oxo-6-(trimethylsilyl)hexahydropentalene-
2,2-dicarboxylate (trans,cis-39) (52.7 mg, 58%) as colorless
crystals, followed by trans-dimethyl 4-isopropylidene-5-oxo-
hexahydropentalene-2,2-dicarboxylate (trans-40) (20.8 mg,
29%).
Ack n ow led gm en t. This work was supported by a
Grant-in-Aid for Scientific Research and the 21st Cen-
tury COE Program “Nature-Guided Materials Process-
ing” of the Ministry of Education, Culture, Sports,
Science, and Technology, J apan. We also gratefully
acknowledge Dr.KozoMatsumoto,Mr.Haruhisa Choushi,
and Mr. Shin-ichi Komai at Nagoya University for the
mass spectral measurements, and the Microanalytical
Center of Kyoto University for the elemental analyses
measurements.
Su p p or tin g In for m a tion Ava ila ble: General experimen-
tal methods, detailed experimental procedures, and charac-
terization data for all allenenes, related references and notes,
1
and H and 13C NMR spectra for all cyclization products. This
material is available free of charge via the Internet at
http://pubs.acs.org.
J O035551X
J . Org. Chem, Vol. 69, No. 2, 2004 405