Journal of the American Chemical Society
Communication
Med. Chem. 1995, 38, 3146. (b) Endo, Y.; Takehana, S.; Ohno, M.;
Driedger, P. E.; Stabel, S.; Mizutani, M. Y.; Tomioka, N.; Itai, A.; Shudo,
K. J. Med. Chem. 1998, 41, 1476. (c) Chung, S. S. W.; Wang, X.; Roberts,
S. S.; Griffey, S. M.; Reczek, P. R.; Wolgemuth, D. J. Endocrinology 2011,
152, 2492. (d) Wood, T. F.; Easter, W. M.; Carpenter, M. S.; Angiolini, J.
J. Org. Chem. 1963, 28, 2248.
(9) (a) Orcutt, R. M.; Bogert, M. Rocz. Chem. 1938, 18, 732.
(b) Condon, F. E.; West, D. L. J. Org. Chem. 1980, 45, 2006.
(10) (a) Bright, S. T.; Coxon, J. M.; Steel, P. J. J. Org. Chem. 1990, 55,
1338. Also see: (b) Schmerling, L.; Vesely, J. A. J. Org. Chem. 1973, 38,
312. (c) Olah, G. A.; Schilling, P.; Staral, J. S.; Halpern, Y.; Olah, J. A. J.
Am. Chem. Soc. 1975, 97, 6807. (d) Yonehara, F.; Kido, Y.; Morita, S.;
Yamaguchi, M. J. Am. Chem. Soc. 2001, 123, 11310.
which also suggests a concerted 1,5-shift pathway. Our
observation reinforces this model, and the enantioretention
during this carbocation-mediated process represents an exciting
and rare finding.
In summary, we have developed a distinct Cu-catalyzed
cascade transformation to form tetralins and cyclopentenes from
readily available starting materials. The related two processes are
made mechanistically distinct by the way in which the initial
carbocation intermediate is translocated to a remote carbon atom
prior to its interception via a Friedel−Crafts-type reaction. A
series of 1,2-hydride shifts define the arylative alkene cascade to
tetralins through a classical cabocation-type pathway. In contrast,
the cyclopentene formation is notable for a concerted 1,5-
hydride shift process that retains stereochemical information at
the site of the carbocation-type intermediate. Overall, we believe
that the efficacy and mechanistic divergency of these strategies
will be broadly useful for the design of novel carbocation
reactions.13
(11) When the reaction to form 3j was performed with TfOD (Table 2,
entry 10) we observed 15% deuterium incorporation at the two
methylene positions in the aliphatic ring, which is suggestive of a hydride
shift mechanism. This reaction was chosen for simplicity, and we note
that it may not be representative of other substrates.
(12) (a) The configuration is assumed on the basis of retention of
configuration. (b) Possible intermediacy of a vinyl triflate:
ASSOCIATED CONTENT
* Supporting Information
Experimental procedures and spectral data. This material is
■
S
(13) For a related reaction using C−H activation on an alkene, see:
Stang, E. M.; White, M. C. J. Am. Chem. Soc. 2011, 133, 14892.
AUTHOR INFORMATION
Corresponding Author
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We are grateful to the ERC and EPSRC for funding. Mass
spectrometry data were acquired at the EPSRC UK National
Mass Spectrometry Facility at Swansea University.
REFERENCES
■
(1) (a) Olah, G. A. J. Org. Chem. 2001, 66, 5944. (b) Naredla, R. R.;
Klumpp, D. A. Chem. Rev. 2013, 113, 6905.
(2) For selected examples, see: (a) Phipps, R. J.; Grimster, N. P.;
Gaunt, M. J. J. Am. Chem. Soc. 2008, 130, 8172. (b) Phipps, R. J.; Gaunt,
M. J. Science 2009, 323, 1593. (c) Phipps, R. J.; McMurray, L.; Ritter, S.;
Duong, H. A.; Gaunt, M. J. J. Am. Chem. Soc. 2012, 134, 10773.
(d) Bigot, A.; Williamson, A. E.; Gaunt, M. J. J. Am. Chem. Soc. 2011,
133, 13778. (e) Suero, M. G.; Bayle, E. D.; Collins, B. S. L.; Gaunt, M. J.
J. Am. Chem. Soc. 2013, 135, 5332. (f) Walkinshaw, A. J.; Xu, W.; Suero,
M. G.; Gaunt, M. J. J. Am. Chem. Soc. 2013, 135, 12532. (g) Allen, A. E.;
MacMillan, D. W. C. J. Am. Chem. Soc. 2011, 133, 4260.
(3) (a) Birladeanu, L. J. Chem. Educ. 2000, 77, 858. (b) Haibach, M. C.;
Seidel, D. Angew. Chem., Int. Ed. 2014, 53, 5010.
(4) For examples of catalytic cyclizations to give tetralins, see:
(a) Youn, S. W.; Pastine, S. J.; Sames, D. Org. Lett. 2004, 6, 581.
(b) Zhang, L.; Kozmin, S. J. Am. Chem. Soc. 2004, 126, 10204.
(c) O’Connor, B.; Zhang, Y.; Negishi, E.-i.; Luo, F.-T.; Cheng, J.-W.
Tetrahedron Lett. 1988, 29, 3903. (d) Inoue, H.; Chatani, N.; Murai, S. J.
Org. Chem. 2002, 67, 1414.
(5) (a) Biermann, U.; Koch, R.; Metzger, J. R. O. Angew. Chem., Int. Ed.
2006, 45, 3076. (b) Jin, T.; Himuro, M.; Yamamoto, Y. J. Am. Chem. Soc.
2010, 132, 5590. (c) Souto, J. A.; Becker, P.; Iglesias, A.; Muniz, K. J. Am.
̃
Chem. Soc. 2012, 134, 15505.
(6) We believe that DTBP and molecular sieves serve as a buffer for the
TfOH generated in the reaction or simply as a desiccant.
(7) For a review see: Merritt, E. A.; Olofsson, B. Angew. Chem., Int. Ed.
2009, 48, 9052.
(8) For examples, see: (a) Boehm, M. F.; Zhang, L.; Zhi, L.; McClurg,
M. R.; Berger, E.; Wagoner, M.; Mais, D. E.; Suto, C. M.; Davies, P. J. A. J.
D
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