Angewandte
Chemie
Table 4: Products (with e.r. values and yields) of the catalytic enantio-
selective alkynylation with aryl-substituted alkynes.[a,b]
[1] Reviews: a) P. R. Schreiner, Chem. Soc. Rev. 2003, 32, 289;
b) P. M. Pihko, Angew. Chem. 2004, 116, 2110; Angew. Chem.
Int. Ed. 2004, 43, 2062; c) C. Bolm, T. Rantanen, I. Schiffers, L.
Zani, Angew. Chem. 2005, 117, 1788; Angew. Chem. Int. Ed.
2005, 44, 1758; d) H. Yamamoto, K. Futatsugi, Angew. Chem.
2005, 117, 1958; Angew. Chem. Int. Ed. 2005, 44, 1924; e) M. S.
Taylor, E. N. Jacobsen, Angew. Chem. 2006, 118, 1550; Angew.
Chem. Int. Ed. 2006, 45, 1520.
[2] a) M. Rueping, C. Azap, E. Sugiono, T. Theissmann, Synlett
2005, 2367; b) M. Rueping, E. Sugiono, C. Azap, T. Theissmann,
M. Bolte, Org. Lett. 2005, 7, 3781; c) M. Rueping, T. Theissmann,
A. P. Antonchick, Synlett 2006, 1071; d) M. Rueping, A. P.
Antonchick, T. Theissmann, Angew. Chem. 2006, 118, 3765;
Angew. Chem. Int. Ed. 2006, 45, 3683; e) M. Rueping, A. P.
Antonchick, T. Theissmann, Angew. Chem. 2006, 118, 6903;
Angew. Chem. Int. Ed. 2006, 45, 6751; f) M. Rueping, E. Sugiono,
C. Azap, Angew. Chem. 2006, 118, 2679; Angew. Chem. Int. Ed.
2006, 45, 2617; g) M. Rueping, C. Azap, Angew. Chem. 2006, 118,
7996; Angew. Chem. Int. Ed. 2006, 45, 7832; h) M. Rueping, E.
Sugiono, T. Theissmann, A. Kuenkel, A. Köckritz, A. Pews
Davtyan, N. Nemati, M. Beller, Org. Lett. 2007, 9, 1065; i) M.
Rueping, E. Sugiono, F. R. Schoepke, Synlett 2007, 144; j) M.
Rueping, E. Sugiono, S. A. Moreth, Adv. Synth. Catal. 2007, 349,
759; k) M. Rueping, W. Ieawsuwan, A. P. Antonchick, B. J.
Nachtsheim, Angew. Chem. 2007, 119, 2143; Angew. Chem. Int.
Ed. 2007, 46, 2097; l) M. Rueping, A. P. Antonchick Angew.
Chem. 2007, 119, 4646; Angew. Chem. Int. Ed. 2007, 46, 4562.
[3] Review: T. Akiyama, J. Itoh, K. Fuchibe, Adv. Synth. Catal. 2006,
348, 999; a) T. Akiyama, J. Itoh, K. Yokota, K. Fuchibe, Angew.
Chem. 2004, 116, 1592; Angew. Chem. Int. Ed. 2004, 43, 1566;
b) D. Uraguchi, M. Terada, J. Am. Chem. Soc. 2004, 126, 5356;
c) M. Terada, K. Sorimachi, D. Uraguchi, Synlett 2006, 13; d) M.
Terada, K. Machioka, K. Sorimachi, Angew. Chem. 2006, 118,
2312; Angew. Chem. Int. Ed. 2006, 45, 2254; e) S. Mayer, B. List,
Angew. Chem. 2006, 118, 4299; Angew. Chem. Int. Ed. 2006, 45,
4193; f) J. Itoh, K. Fuchibe, T. Akiyama, Angew. Chem. 2006,
118, 4914; Angew. Chem. Int. Ed. 2006, 45, 4796; g) D.
Nakashima, H. Yamamoto, J. Am. Chem. Soc. 2006, 128, 9626;
h) A. Hasegawa, Y. Naganawa, M. Fushimi, K. Ishihara, H.
Yamamoto, Org. Lett. 2006, 8, 3175; i) S. Hoffmann, M. Nicoletti,
B. List, J. Am. Chem. Soc. 2006, 128, 13074; j) N. J. A. Martin, B.
List, J. Am. Chem. Soc. 2006, 128, 13368; k) T. Akiyama, H.
Morita, K. Fuchibe, J. Am. Chem. Soc. 2006, 128, 13070; l) X.-H.
Chen, X.-Y. Xu, H. Liu, L.-F. Cun, L.-Z. Gong, J. Am. Chem.
Soc. 2006, 128, 14802; m) H. Liu, L.-F. Cun, A. Q. Mi, Y. Z.
Jiang, L. Z. Gong, Org. Lett. 2006, 8, 6023; n) M. Terada, K.
Sorimachi, J. Am. Chem. Soc. 2007, 129, 292; o) Q. Kang, Z.-A.
Zhao, S.-L. You, J. Am. Chem. Soc. 2007, 129, 1484; p) G. Li, Y.
Liang, J. C. Antilla, J. Am. Chem. Soc. 2007, 129, 5830.
[4] D. Enders, U. Reinhold, Tetrahedron: Asymmetry 1997, 8, 1895.
[5] a) D. E. Frantz, R. Fꢀssler, E. M. Carreira, J. Am. Chem. Soc.
1999, 121, 11245; b) D. E. Frantz, R. Fꢀssler, C. S. Tomooka,
E. M. Carreira, Acc. Chem. Res. 2000, 33, 373; c) C. Koradin, K.
Polborn, P. Knochel, Angew. Chem. 2002, 114, 2651; Angew.
Chem. Int. Ed. 2002, 41, 2535; d) R. Fꢀssler, D. E. Frantz, J.
Oetiker, E. M. Carreira, Angew. Chem. 2002, 114, 3180; Angew.
Chem. Int. Ed. 2002, 41, 3054; e) C. Wei, C.-J. Li, J. Am. Chem.
Soc. 2002, 124, 5638; f) T. F. Knöpfel, E. M. Carreira, J. Am.
Chem. Soc. 2003, 125, 6054; g) N. Gommermann, X. Koradin, K.
Polborn, P. Knochel, Angew. Chem. 2003, 115, 5941; Angew.
Chem. Int. Ed. 2003, 42, 5763; h) C. Koradin, N. Gommermann,
K. Polborn, P. Knochel, Chem. Eur. J. 2003, 9, 2797; i) C. Fischer,
E. M. Carreira, Org. Lett. 2004, 6, 1497; j) N. Gommermann, P.
Knochel, Chem. Commun. 2004, 2324; k) N. Gommermann, P.
Knochel, Chem. Commun. 2005, 4175; l) J. X. Ji, J. Wu, A. S. C.
Chan, Proc. Natl. Acad. Sci. USA 2005, 102, 11196; m) T. F.
[a] Reaction conditions: 2b, 4a–h (2 equiv), 10 mol% 1g, 5 mol%
AgOAc at 308C in toluene. [b] Yield after chromatography. Enantiose-
lectivities were determined byHPLC analysis using a chiral stationary
phase.[13]
In summary, we have reported a new dual catalysis
procedure, in which an enantioselective activation catalyzed
by a Brønsted acid is combined with a metal-catalyzed
alkynylation. The special features are the mild reaction
conditions and the operational simplicity and practicability,
which even negate the need to preform the catalyst. The new
amino acids obtained have been isolated in good yields and
with excellent enantiomeric ratios (up to e.r. 96:4). Further-
more, this unprecedented dual catalysis procedure represents
not only the first addition of an organometallic compound to a
aldimine activated with a binol phosphate, but more impor-
tantly, in this process both the metal salt and the Brønsted
acid can be employed in catalytic amounts. We assume the
reaction mechanism involves the formation of a chiral silver–
binol phosphate complex, which results in a new metal-
catalyzed reaction, in which the chiral counterion induces the
enantioselectivity.
Further work will be directed toward a more detailed
examination and application of the dual catalysis procedure
as well as asymmetric metal catalysis with chiral counterions.
Received: June 5, 2007
Published online: August 10, 2007
Keywords: alkynes · asymmetric catalysis · binol phosphate ·
.
silver
Angew. Chem. Int. Ed. 2007, 46, 6903 –6906
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim