Journal of the American Chemical Society
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(5) (a) Ghosh, A. K.; Xu, X. M. Org. Lett. 2004, 6, 2055. (b) Chen, J.;
Forsyth, C. J. Angew. Chem., Int. Ed. 2004, 43, 2148. (c) Ferrie, L.;
Reymond, S.; Capdevielle, P.; Cossy, J. Org. Lett. 2006, 8, 3441.
(d) Chandrasekhar, S.; Mahipal, B.; Kavitha, M. J. Org. Chem. 2009,
74, 9531. (e) Tannert, R.; Milroy, L. G.; Ellinger, B.; Hu, T. S.; Arndt,
H. D.; Waldmann, H. J. Am. Chem. Soc. 2010, 132, 3063.
(18) Matteson, D. S.; Sadhu, K. M.; Peterson, M. L. J. Am. Chem. Soc.
1986, 108, 810.
(19) Matteson, D. S.; Maliakal, D.; Pharazyn, P. S.; Kim, B. J. Synlett
2006, 3501.
(20) Molander, G. A.; Cavalcanti, L. N.; Canturk, B.; Pan, P.-S.;
Kennedy, L. E. J. Org. Chem. 2009, 74, 7364.
(6) Zimmerman, H. E.; Traxler, M. D. J. Am. Chem. Soc. 1957,
(21) The Z isomer was obtained in slightly lower er (93:7) with the
79, 1920.
opposite configuration. The er was measured using chiral HPLC.
(7) (a) Lucke, A. J.; Young, D. J. J. Org. Chem. 2005, 70, 3579.
(b) K€oster, R.; Arora, S.; Binger, P. Angew. Chem., Int. Ed. Engl. 1969,
8, 205. (c) Hill, E. A.; Park, Y. W. J. Organomet. Chem. 1988, 356, 1. For
reactivity of an analogous silane, see: (d) Grignon-Dubois, M.;
Dunoguꢀes, J.; Calas, E. Can. J. Chem. 1981, 59, 802.
(8) Yang, Z. Q.; Lorenz, J. C.; Shi, Y. Tetrahedron Lett. 1998,
39, 8621.
(9) (a) Kennedy, J. W. J.; Hall, D. G. J. Am. Chem. Soc. 2002,
124, 11586. (b) Ishiyama, T.; Ahiko, T.; Miyaura, N. J. Am. Chem. Soc.
2002, 124, 12414. (c) Lachance, H.; Lu, X. S.; Gravel, M.; Hall, D. G.
J. Am. Chem. Soc. 2003, 125, 10160. (d) Rauniyar, V.; Hall, D. G.
J. Am. Chem. Soc. 2004, 126, 4518. (e) Gravel, M.; Lachance, H.; Lu,
X. S.; Hall, D. G. Synthesis 2004, 1290. (f) Carosi, L.; Lachance, H.; Hall,
D. G. Tetrahedron Lett. 2005, 46, 8981. (g) Ramachandran, P. V.;
Pratihar, D.; Biswas, D. Org. Lett. 2006, 8, 3877. (h) Rauniyar, V.; Hall,
D. G. Angew. Chem., Int. Ed. 2006, 45, 2426. (i) Lou, S.; Moquist, P. N.;
Schaus, S. E. J. Am. Chem. Soc. 2006, 128, 12660. (j) Elford, T. G.;
Arimura, Y.; Yu, S. H.; Hall, D. G. J. Org. Chem. 2007, 72, 1276.
(k) Ramachandran, P. V.; Pratihar, D. Org. Lett. 2007, 9, 2087. (l) Hall,
D. G. Synlett 2007, 1644. (m) Rauniyar, V.; Hall, D. G. Synthesis 2007,
3421. (n) Lira, R.; Roush, W. R. Org. Lett. 2007, 9, 4315. (o) Carosi, L.;
Hall, D. G. Angew. Chem., Int. Ed. 2007, 46, 5913. (p) Lou, S.; Moquist,
P. N.; Schaus, S. E. J. Am. Chem. Soc. 2007, 129, 15398. (q) Rauniyar, V.;
Zhai, H. M.; Hall, D. G. J. Am. Chem. Soc. 2008, 130, 8481. (r) Rauniyar,
V.; Hall, D. G. J. Org. Chem. 2009, 74, 4236. (s) Barnett, D. S.; Moquist,
P. N.; Schaus, S. E. Angew. Chem., Int. Ed. 2009, 48, 8679. (t) Chen, M.;
Roush, W. R. Org. Lett. 2010, 12, 2706–2709. (u) Jain, P.; Antilla, J. C.
J. Am. Chem. Soc. 2010, 132, 11884.
(10) Aldehydes in fact react with PhBCl2 quantitatively to form
α-chloro ethers, which are hydrolyzed back to the aldehydes upon
aqueous workup. Similar boron species have been observed by Lappert,
and analogous silicon species have been reported by Denmark. See:
(a) Frazer, M. J.; Gerrard, W.; Lappert, M. F. J. Chem. Soc. 1957, 739.
(b) Denmark, S. E.; Wynn, T.; Beutner, G. L. J. Am. Chem. Soc. 2002,
124, 13405.
(11) (a) Evans, D. A.; Allison, B. D.; Yang, M. G. Tetrahedron Lett.
1999, 40, 4457. (b) Evans, D. A.; Halstead, D. P.; Allison, B. D.
Tetrahedron Lett. 1999, 40, 4461. (c) Evans, D. A.; Allison, B. D.; Yang,
M. G.; Masse, C. E. J. Am. Chem. Soc. 2001, 123, 10840.
(12) This result does not necessarily confirm the involvement of a
cationic reaction manifold, as we would expect Ag(OCOCF3) to replace
chloride with the more strongly coordinating trifluoroacetate. By con-
trast, use of Ag(SbF6) as the additive results in an intractable complex
mixture.
(13) Coutts, S. J.; Adams, J.; Krolikowski, D.; Snow, R. J. Tetrahedron
Lett. 1994, 35, 5109.
(14) When run at À35 °C, the reaction was incomplete after days
and the selectivity was not greatly improved.
(15) The minor diastereomer 18-a presumably is produced from a
cis impurity (16) present at a ∼5% level in the trans reagent 17. Since
16 is more reactive than 17 and 3 equiv of the reagent mixture was used,
the percentage of the minor diastereomer was slightly amplified in the
homocrotylation product 18-s relative to reagent 17.
(16) The diastereomeric ratios for 18-s and 17 were measured by
integration of 1H NMR signals.
(17) This is true under the assumption that only one bond of the
cyclopropane is cleaved during the conversion of 16 to 18-a. Alternative
mechanisms leading to 18-a but involving cleavage of the other cyclopro-
pane bonds would be very complex and are inconsistent with the high
observed diastereoselectivity.
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dx.doi.org/10.1021/ja2048682 |J. Am. Chem. Soc. 2011, 133, 18514–18517