Regioselectivity in nucleophilic addition of siloxyalkenes to an alkylideneallyl cation

Chemistry Letters

Volumn 35, Issue 4, 2006, Pages 382-383

  Fujita, Morifumi ^a   Fujiwara, Koji ^a   Okuyama, Tadashi ^a  

^a UNIVERSITY OF HYOGO   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 33646690154     PISSN: 03667022     EISSN: None     Source Type: Journal    
DOI: 10.1246/cl.2006.382     Document Type: Article

References (15)

1. a) H.-U. Siehl, H. Mayr, J. Am. Chem. Soc. 1982, 104, 909.
2. b) H.-U. Siehl, in Dicoordinated Carbocations, ed. by Z. Rappoport, P. J. Stang, John Wiley & Sons, New York, 1997, Chap. 5, pp. 189-236.
3. a) H.-U. Siehl, S. Brixner, J. Phys. Org. Chem. 2004, 17, 1039.
4. b) H.-U. Siehl, T. Müller, J. Gauss, J. Phys. Org. Chem. 2003, 16, 577.
5. c) Y. Apeloig, T. Müller, in Dicoordinated Carbocations, ed. by Z. Rappoport, P. J. Stang, John Wiley & Sons, New York, 1997, Chap. 2, pp. 9-104.
6. M. Fujita, K. Fujiwara, H. Mouri, Y. Kazekami, T. Okuyama, Tetrahedron Lett. 2004, 45, 8023.
7. The orientation of the five-membered ring of 7-9 is also confirmed by the conversion reaction from 7 to 8 and 9. The diene structure of 8 indicates that the siloxy of 7 is at allylic position.
8. 4 in the absence of 5 gives 3 selectively. This suggests the allylic cation contains methoxy group.
9. 6b
10. b) E. Nakamura, S. Yamago, Acc. Chem. Res. 2002, 35, 867, and references cited therein.
11. The vacant orbital at the sp carbon of 2 may be shielded by the cyclohexane ring, but some nucleophiles including chloride and furans prefer the sp attack. So, the present selectivity may be controlled mainly by the charge distribution.
12. 2 center.
13. Lewis acid-mediated reactions of cyclopropanes with siloxyalkenes, see: a) M. Ohno, S. Matsuoka, S. Eguchi, J. Org. Chem. 1986, 51, 4553.
14. b) K. Saigo, S. Shimada, T. Shibasaki, M. Hasegawa, Chem. Lett. 1990, 1093.
15. C. A. Grob, R. Spaar, Helv. Chim. Acta 1970, 53, 2119.