reaction of 1a with 2a smoothly proceeds at 20 °C in the
presence of ligand 713 to give cycloheptane 3aa in 87% yield
with 86% ee.14 Similarly, lactone 1f gives 3fa in 87% yield
with 93% ee at 40 °C, and the same chiral phosphoramidite
ligand is also effective for the reaction of 1a with aziridine
5 to give azepane (R)-615 with 85% ee (eq 3).
Table 3. Palladium-Catalyzed Ring Expansion of 1 with 2a
entry
1
product yield (%)a
1b
2
3
1g (R1 ) CH2Ph, R2 ) CO2Me)
1g
8ga
8ga
8ha
8ia
58
73
78
72
93
1h (R1 ) Me, R2 ) CO2Me)
1i (R1 ) Et, R2 ) CO2Me)
1j (R1 ) R2 ) Ph)
4
5c
8ja
a Isolated yield. b The reaction conditions for Table 2, entry 1 (ligand
4a at 80 °C for 12 h), were employed. c 1.0 equiv of 1j (1.20 mol/L) and
1.4 equiv of 2a were used.
Scheme 1. Proposed Catalytic Cycles for the
Palladium-Catalyzed Cyclizations of 1 with 2a
It is worth noting that the course of the reactions between
1 and 2 can be completely switched from decarboxylative
[4 + 3] cyclizations to nondecarboxylative formal [6 + 3]
cyclizations16 to give ring-expanded nine-membered lac-
tones17 simply by changing the electronic nature of the
lactone substituents. Thus, a reaction of lactone 1g having a
benzyl group at the R-position with cyclopropane 2a under
the same conditions as in Table 2 (Pd/4a catalyst at 80 °C)
gave nine-membered lactone 8ga in 58% yield with no
formation of the decarboxylated seven-membered carbocycle
(Table 3, entry 1). The yield of 8ga could be improved to
73% by conducting the reaction with ligand 4b18 at 65 °C
(entry 2). Under these conditions, other R-alkyl lactones (1h
and 1i) as well as lactone 1j also provide the ring-expanded
(11) (a) Chong, H.-s.; Ganguly, B.; Broker, G. A.; Rogers, R. D.;
Brechbiel, M. W. J. Chem. Soc., Perkin Trans. 1 2002, 2080. (b) Li, H.;
Ble´riot, Y.; Chantereau, C.; Mallet, J.-M.; Sollogoub, M.; Zhang, Y.;
Rodr´ıguez-Garc´ıa, E.; Vogel, P.; Jime´nez-Barbero, J.; Sinay¨, P. Org. Biomol.
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PrakashaReddy, J. J. Org. Chem. 2004, 69, 4760. (d) Lee, S. J.; Beak, P.
J. Am. Chem. Soc. 2006, 128, 2178.
(12) (a) Trost, B. M.; Jiang, C. Synthesis 2006, 369. (b) Christoffers,
J.; Baro, A. AdV. Synth. Catal. 2005, 347, 1473. (c) Douglas, C. J.; Overman,
L. E Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 5363.
(13) (a) Choi, Y. H.; Choi, J. Y.; Yang, H. Y.; Kim, Y. H. Tetrahedron:
Asymmetry 2002, 13, 801. (b) Trost, B. M.; Stambuli, J. P.; Silverman,
S. M.; Schwo¨rer, U. J. Am. Chem. Soc. 2006, 128, 13328. See also: (c)
Trost, B. M.; Cramer, N.; Silverman, S. M. J. Am. Chem. Soc. 2007, 129,
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Soc. 2007, 129, 12398.
nine-membered lactones 8 with complete selectivity (72-93%
yield; entries 3-5).
With regard to the reaction pathways for the present
catalyses, proposed catalytic cycles for the reaction of lactone
1 with cyclopropane 2a are illustrated in Scheme 1. Thus,
oxidative addition of the allyl ester moiety of 1 to pal-
ladium(0) gives π-allylpalladium carboxylate A. Successive
decarboxylation19,20 takes place when R is an aryl group,
which can stabilize the resulting anionic charge on the
(14) See Supporting Information for representative results.
(15) The absolute configuration was determined by X-ray crystal-
lographic analysis (see Supporting Information for details).
(16) (a) Trost, B. M.; Seoane, P. R. J. Am. Chem. Soc. 1987, 109, 615.
(b) Trost, B. M.; McDougall, P. J.; Hartmann, O.; Wathen, P. T. J. Am.
Chem. Soc. 2008, 130, 14960. (c) Chaffee, K.; Morcos, H.; Sheridan, J. B.
Tetrahedron Lett. 1995, 36, 1577.
(17) (a) Shiina, I. Chem. ReV. 2007, 107, 239. (b) Lenoble, G.;
Urrutigo¨ıty, M.; Kalck, P. Tetrahedron Lett. 2001, 42, 3697. (c) Ferraz,
H. M. C.; Longo, S. L., Jr. J. Org. Chem. 2007, 72, 2945. (d) Pradhan,
T. K.; Hassner, A. Synthesis 2007, 3361. (e) Ram´ırez-Ferna´ndez, J.; Collado,
I. G.; Herna´ndez-Gala´n, R. Synlett 2008, 339.
(19) (a) Shimizu, I.; Yamada, T.; Tsuji, J. Tetrahedron Lett. 1980, 21,
3199. (b) Tsuda, T.; Chuji, Y.; Nishi, S.; Tawara, K.; Saegusa, T. J. Am.
Chem. Soc. 1980, 102, 6381. For reviews, see: (c) Tunge, J. A.; Burger,
E. C. Eur. J. Org. Chem. 2005, 1715. (d) You, S.-L.; Dai, L.-X. Angew.
Chem., Int. Ed. 2006, 45, 5246.
(18) van Strijdonck, G. P. F.; Boele, M. D. K.; Kamer, P. C. J.; de Vries,
J. G.; van Leeuwen, P. W. N. M. Eur. J. Inorg. Chem. 1999, 1073.
5644
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