Intramolecular cyclization reaction via a sterically protected episelenonium ion intermediate

Chemistry Letters

Volumn , Issue 8, 1997, Pages 733-734

  Toshimitsu, Akio ^a   Terada, Masayoshi ^a   Tamao, Kohei ^a  

^a KYOTO UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0031533592     PISSN: 03667022     EISSN: None     Source Type: Journal    
DOI: 10.1246/cl.1997.733     Document Type: Article

References (12)

1. A. Toshimitsu, K. Nakano, T. Mukai, and K. Tamao, J. Am. Chem. Soc., 118, 2756 (1996).
2. The migration of the phenylseleno group to the carbon atom of other (intra-or inter-molecular) double bond has been reported: See for example; T. Kametani, H. Kurobe, and H. Nemoto, J. Chem. Soc., Perkin Trans. 1, 1981, 756; W. P. Jackson, S. V. Ley, and J. A. Morton, Tetrahedron Lett., 22, 2601 (1981); F. Rouessac and H. Zamarlik, Tetrahedron Lett., 22, 2643 (1981); A. Rouessac and F. Rouessac, Tetrahedron, 37, 4165 (1981); T. Kametani, H. Kurobe, H. Nemoto, and K. Fukumoto, J. Chem. Soc., Perkin Trans. 1, 1982, 1085; A. Toshimitsu, T. Kusumoto, and S. Tanimoto, Bull. Inst. Chem. Res., Kyoto Univ., 70, 270 (1992).
3. The migration of the phenylseleno group to the carbon atom of other (intra-or inter-molecular) double bond has been reported: See for example; T. Kametani, H. Kurobe, and H. Nemoto, J. Chem. Soc., Perkin Trans. 1, 1981, 756; W. P. Jackson, S. V. Ley, and J. A. Morton, Tetrahedron Lett., 22, 2601 (1981); F. Rouessac and H. Zamarlik, Tetrahedron Lett., 22, 2643 (1981); A. Rouessac and F. Rouessac, Tetrahedron, 37, 4165 (1981); T. Kametani, H. Kurobe, H. Nemoto, and K. Fukumoto, J. Chem. Soc., Perkin Trans. 1, 1982, 1085; A. Toshimitsu, T. Kusumoto, and S. Tanimoto, Bull. Inst. Chem. Res., Kyoto Univ., 70, 270 (1992).
4. The migration of the phenylseleno group to the carbon atom of other (intra-or inter-molecular) double bond has been reported: See for example; T. Kametani, H. Kurobe, and H. Nemoto, J. Chem. Soc., Perkin Trans. 1, 1981, 756; W. P. Jackson, S. V. Ley, and J. A. Morton, Tetrahedron Lett., 22, 2601 (1981); F. Rouessac and H. Zamarlik, Tetrahedron Lett., 22, 2643 (1981); A. Rouessac and F. Rouessac, Tetrahedron, 37, 4165 (1981); T. Kametani, H. Kurobe, H. Nemoto, and K. Fukumoto, J. Chem. Soc., Perkin Trans. 1, 1982, 1085; A. Toshimitsu, T. Kusumoto, and S. Tanimoto, Bull. Inst. Chem. Res., Kyoto Univ., 70, 270 (1992).
5. The migration of the phenylseleno group to the carbon atom of other (intra-or inter-molecular) double bond has been reported: See for example; T. Kametani, H. Kurobe, and H. Nemoto, J. Chem. Soc., Perkin Trans. 1, 1981, 756; W. P. Jackson, S. V. Ley, and J. A. Morton, Tetrahedron Lett., 22, 2601 (1981); F. Rouessac and H. Zamarlik, Tetrahedron Lett., 22, 2643 (1981); A. Rouessac and F. Rouessac, Tetrahedron, 37, 4165 (1981); T. Kametani, H. Kurobe, H. Nemoto, and K. Fukumoto, J. Chem. Soc., Perkin Trans. 1, 1982, 1085; A. Toshimitsu, T. Kusumoto, and S. Tanimoto, Bull. Inst. Chem. Res., Kyoto Univ., 70, 270 (1992).
6. The migration of the phenylseleno group to the carbon atom of other (intra-or inter-molecular) double bond has been reported: See for example; T. Kametani, H. Kurobe, and H. Nemoto, J. Chem. Soc., Perkin Trans. 1, 1981, 756; W. P. Jackson, S. V. Ley, and J. A. Morton, Tetrahedron Lett., 22, 2601 (1981); F. Rouessac and H. Zamarlik, Tetrahedron Lett., 22, 2643 (1981); A. Rouessac and F. Rouessac, Tetrahedron, 37, 4165 (1981); T. Kametani, H. Kurobe, H. Nemoto, and K. Fukumoto, J. Chem. Soc., Perkin Trans. 1, 1982, 1085; A. Toshimitsu, T. Kusumoto, and S. Tanimoto, Bull. Inst. Chem. Res., Kyoto Univ., 70, 270 (1992).
7. The migration of the phenylseleno group to the carbon atom of other (intra-or inter-molecular) double bond has been reported: See for example; T. Kametani, H. Kurobe, and H. Nemoto, J. Chem. Soc., Perkin Trans. 1, 1981, 756; W. P. Jackson, S. V. Ley, and J. A. Morton, Tetrahedron Lett., 22, 2601 (1981); F. Rouessac and H. Zamarlik, Tetrahedron Lett., 22, 2643 (1981); A. Rouessac and F. Rouessac, Tetrahedron, 37, 4165 (1981); T. Kametani, H. Kurobe, H. Nemoto, and K. Fukumoto, J. Chem. Soc., Perkin Trans. 1, 1982, 1085; A. Toshimitsu, T. Kusumoto, and S. Tanimoto, Bull. Inst. Chem. Res., Kyoto Univ., 70, 270 (1992).
8. This result seems to indicate that the TTBPSe group does not migrate to the other double bond during the reaction. However, the possibility of the migration has not yet been completely ruled out, since it is possible that, under the equilibrium of two episelenonium ion intermediates (7 and its isomer), only 7 affords the cyclized product due to the stability of tertiary carbocation.
9. Starting materials Z-and E-11 were prepared by the Wittig reaction using triphenyl(3-phenylpropyl)phosphonium chloride and 5-acetoxy-6-(2,4,6-tri-tert-butylphenylseleno)-2-hexanone. The E and Z isomers were separated by medium pressured column chromatography and assigned by the NOE measurement.
10. The bicyclic product from each substrate was confirmed to consist of one stereoisomer. Their 13C NMR (67.94 MHz) spectra are as follows: 12; 25.2(t), 26.7(q), 29.2(t), 30.3(t), 31.3(q), 33.1(q), 34.5(t), 34.8(s), 36.6(s), 37.9(t), 39.0(s), 41.5(d), 44.9(d), 121.8(d), 125.2(d), 125.8(d), 126.1(s), 126.6(d), 128.9(d), 135.5(s), 146.2(s), 148.9(s), and 155.2(s); 13; δ 21.8(q), 25.4(t), 28.4(t), 29.2(t), 31.4(q), 33.1(q), 34.8(t), 34.9(s), 36.5(s), 38.7(t), 39.0(s), 43.1(d), 47.3(d), 121.7(d), 124.5(d), 125.4(s), 125.5(d), 128.3(d), 129.2(d), 135.3(s), 147.4(s), 149.1(s), and 155.5(s).
11. Side products were monocyclic olefins formed by the deprotonation of the cation. Total yields of the regioisomeric olefins were 18% from Z-11 and 35% from E-11, tetra-substituted olefin being the major isomer in both cases.
12. Crystals of 12 were obtained by recrystallization from 2-propanol. The result of the X-ray crystallographic analysis in Scheme 4 was drawn at the 30% probability level. All hydrogen atoms are omitted for clarity.