Sulfur-functionalized olefins for titanacycle formation: Tandem asymmetric cyclization and the pummerer reaction based on sulfoxides promoted by titanium(II)-to-titanium(IV) relay

Angewandte Chemie - International Edition

Volumn 41, Issue 19, 2002, Pages 3671-3674

  Narita, Miho ^a   Urabe, Hirokazu ^a   Sato, Fumie ^a  

^a TOKYO INSTITUTE OF TECHNOLOGY   (Japan)

Author keywords

Cyclization; Metallacycles; Pummerer reaction; Sulfoxides; Synthetic methods; Titanium

Indexed keywords

ALDEHYDES; REUSABILITY; SULFUR; SYNTHESIS (CHEMICAL); TITANIUM;

CYCLIZATION;

OLEFINS;

ALKENE DERIVATIVE; SULFOXIDE; SULFUR; TITANIUM DERIVATIVE;

ARTICLE; CYCLIZATION; REACTION ANALYSIS; STEREOCHEMISTRY; STEREOSPECIFICITY; STOICHIOMETRY;

EID: 0037020348     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/1521-3773(20021004)41:19<3671::AID-ANIE3671>3.0.CO;2-X     Document Type: Article

References (41)

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3. For reviews on group four-metal-mediated enyne cyclization, see: S. L. Buchwald, R. B. Nielsen. Chem. Rev. 1988, 88, 1047-1058; E. Negishi in Comprehensive Organic Synthesis, Vol. 5 (Eds.: B. M. Trost, I. Fleming, L. A. Paquette), Pergamon, Oxford, 1991, pp. 1163-1184; E. Negishi, T. Takahashi, Acc. Chem. Res. 1994, 27, 124-130; M. Maier in Organic Synthesis Highlights II (Ed.: H. Waldmann), VCH, Weinheim, 1995, pp. 99-113.
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5. For reviews on group four-metal-mediated enyne cyclization, see: S. L. Buchwald, R. B. Nielsen. Chem. Rev. 1988, 88, 1047-1058; E. Negishi in Comprehensive Organic Synthesis, Vol. 5 (Eds.: B. M. Trost, I. Fleming, L. A. Paquette), Pergamon, Oxford, 1991, pp. 1163-1184; E. Negishi, T. Takahashi, Acc. Chem. Res. 1994, 27, 124-130; M. Maier in Organic Synthesis Highlights II (Ed.: H. Waldmann), VCH, Weinheim, 1995, pp. 99-113.
6. For reviews on group four-metal-mediated enyne cyclization, see: S. L. Buchwald, R. B. Nielsen. Chem. Rev. 1988, 88, 1047-1058; E. Negishi in Comprehensive Organic Synthesis, Vol. 5 (Eds.: B. M. Trost, I. Fleming, L. A. Paquette), Pergamon, Oxford, 1991, pp. 1163-1184; E. Negishi, T. Takahashi, Acc. Chem. Res. 1994, 27, 124-130; M. Maier in Organic Synthesis Highlights II (Ed.: H. Waldmann), VCH, Weinheim, 1995, pp. 99-113.
7. For reviews on titanium alkoxide-mediated enyne cyclization, see: F. Sato, H. Urabe, S. Okamoto, Pure Appl. Chem. 1999, 71, 1511-1519; F. Sato, H. Urabe, S. Okamoto, Synlett 2000, 753-775; F. Sato, H. Urabe, S. Okamoto, Chem. Rev. 2000, 100, 2835-2886; O. G. Kulinkovich, A. de Meijere, Chem. Rev. 2000, 100, 2789-2834; J. J. Eisch, J. Organomet. Chem. 2001, 617-618, 148-157; F. Sato, S. Okamoto, Adv. Synth. Catal. 2001, 343, 759-784; F. Sato, H. Urabe in Titanium and Zirconium in Organic Synthesis (Ed.: I. Marek), Wiley-VCH, Weinheim, 2002, pp. 319-354.
8. For reviews on titanium alkoxide-mediated enyne cyclization, see: F. Sato, H. Urabe, S. Okamoto, Pure Appl. Chem. 1999, 71, 1511-1519; F. Sato, H. Urabe, S. Okamoto, Synlett 2000, 753-775; F. Sato, H. Urabe, S. Okamoto, Chem. Rev. 2000, 100, 2835-2886; O. G. Kulinkovich, A. de Meijere, Chem. Rev. 2000, 100, 2789-2834; J. J. Eisch, J. Organomet. Chem. 2001, 617-618, 148-157; F. Sato, S. Okamoto, Adv. Synth. Catal. 2001, 343, 759-784; F. Sato, H. Urabe in Titanium and Zirconium in Organic Synthesis (Ed.: I. Marek), Wiley-VCH, Weinheim, 2002, pp. 319-354.
9. For reviews on titanium alkoxide-mediated enyne cyclization, see: F. Sato, H. Urabe, S. Okamoto, Pure Appl. Chem. 1999, 71, 1511-1519; F. Sato, H. Urabe, S. Okamoto, Synlett 2000, 753-775; F. Sato, H. Urabe, S. Okamoto, Chem. Rev. 2000, 100, 2835-2886; O. G. Kulinkovich, A. de Meijere, Chem. Rev. 2000, 100, 2789-2834; J. J. Eisch, J. Organomet. Chem. 2001, 617-618, 148-157; F. Sato, S. Okamoto, Adv. Synth. Catal. 2001, 343, 759-784; F. Sato, H. Urabe in Titanium and Zirconium in Organic Synthesis (Ed.: I. Marek), Wiley-VCH, Weinheim, 2002, pp. 319-354.
10. For reviews on titanium alkoxide-mediated enyne cyclization, see: F. Sato, H. Urabe, S. Okamoto, Pure Appl. Chem. 1999, 71, 1511-1519; F. Sato, H. Urabe, S. Okamoto, Synlett 2000, 753-775; F. Sato, H. Urabe, S. Okamoto, Chem. Rev. 2000, 100, 2835-2886; O. G. Kulinkovich, A. de Meijere, Chem. Rev. 2000, 100, 2789-2834; J. J. Eisch, J. Organomet. Chem. 2001, 617-618, 148-157; F. Sato, S. Okamoto, Adv. Synth. Catal. 2001, 343, 759-784; F. Sato, H. Urabe in Titanium and Zirconium in Organic Synthesis (Ed.: I. Marek), Wiley-VCH, Weinheim, 2002, pp. 319-354.
11. For reviews on titanium alkoxide-mediated enyne cyclization, see: F. Sato, H. Urabe, S. Okamoto, Pure Appl. Chem. 1999, 71, 1511-1519; F. Sato, H. Urabe, S. Okamoto, Synlett 2000, 753-775; F. Sato, H. Urabe, S. Okamoto, Chem. Rev. 2000, 100, 2835-2886; O. G. Kulinkovich, A. de Meijere, Chem. Rev. 2000, 100, 2789-2834; J. J. Eisch, J. Organomet. Chem. 2001, 617-618, 148-157; F. Sato, S. Okamoto, Adv. Synth. Catal. 2001, 343, 759-784; F. Sato, H. Urabe in Titanium and Zirconium in Organic Synthesis (Ed.: I. Marek), Wiley-VCH, Weinheim, 2002, pp. 319-354.
12. For reviews on titanium alkoxide-mediated enyne cyclization, see: F. Sato, H. Urabe, S. Okamoto, Pure Appl. Chem. 1999, 71, 1511-1519; F. Sato, H. Urabe, S. Okamoto, Synlett 2000, 753-775; F. Sato, H. Urabe, S. Okamoto, Chem. Rev. 2000, 100, 2835-2886; O. G. Kulinkovich, A. de Meijere, Chem. Rev. 2000, 100, 2789-2834; J. J. Eisch, J. Organomet. Chem. 2001, 617-618, 148-157; F. Sato, S. Okamoto, Adv. Synth. Catal. 2001, 343, 759-784; F. Sato, H. Urabe in Titanium and Zirconium in Organic Synthesis (Ed.: I. Marek), Wiley-VCH, Weinheim, 2002, pp. 319-354.
13. For reviews on titanium alkoxide-mediated enyne cyclization, see: F. Sato, H. Urabe, S. Okamoto, Pure Appl. Chem. 1999, 71, 1511-1519; F. Sato, H. Urabe, S. Okamoto, Synlett 2000, 753-775; F. Sato, H. Urabe, S. Okamoto, Chem. Rev. 2000, 100, 2835-2886; O. G. Kulinkovich, A. de Meijere, Chem. Rev. 2000, 100, 2789-2834; J. J. Eisch, J. Organomet. Chem. 2001, 617-618, 148-157; F. Sato, S. Okamoto, Adv. Synth. Catal. 2001, 343, 759-784; F. Sato, H. Urabe in Titanium and Zirconium in Organic Synthesis (Ed.: I. Marek), Wiley-VCH, Weinheim, 2002, pp. 319-354.
14. For precedents, zirconacycles generated from acetylenic sulfides are known, but, in these cases, no unique behavior of the functionalized metallacycles has been observed. B. C. Van Wagenen, T. Livinghouse, Tetrahedron Lett. 1989, 30, 3495-3498; B. L. Pagenkopf, E. C. Lund, T. Livinghouse, Tetrahedron 1995, 51, 4421-4438; M. I. Kemp, R. J. Whitby, S. J. Coote, Synthesis 1998, 557-568. Olefinic sulfur compounds have not been investigated in a similar reaction. For a recent application of sulfur-functionalized enynes in the cobalt-mediated Pauson-Khand reaction, see: J. Adrio, J. C. Carretero, J. Am. Chem. Soc. 1999, 121, 7411-7412; J. Adrio, M. R. Rivero, J. C. Carretero, Chem. Eur J. 2001, 7, 2435-2448; J. C. Carretero, J. Adrio, Synthesis 2001, 1888-1896.
15. For precedents, zirconacycles generated from acetylenic sulfides are known, but, in these cases, no unique behavior of the functionalized metallacycles has been observed. B. C. Van Wagenen, T. Livinghouse, Tetrahedron Lett. 1989, 30, 3495-3498; B. L. Pagenkopf, E. C. Lund, T. Livinghouse, Tetrahedron 1995, 51, 4421-4438; M. I. Kemp, R. J. Whitby, S. J. Coote, Synthesis 1998, 557-568. Olefinic sulfur compounds have not been investigated in a similar reaction. For a recent application of sulfur-functionalized enynes in the cobalt-mediated Pauson-Khand reaction, see: J. Adrio, J. C. Carretero, J. Am. Chem. Soc. 1999, 121, 7411-7412; J. Adrio, M. R. Rivero, J. C. Carretero, Chem. Eur J. 2001, 7, 2435-2448; J. C. Carretero, J. Adrio, Synthesis 2001, 1888-1896.
16. For precedents, zirconacycles generated from acetylenic sulfides are known, but, in these cases, no unique behavior of the functionalized metallacycles has been observed. B. C. Van Wagenen, T. Livinghouse, Tetrahedron Lett. 1989, 30, 3495-3498; B. L. Pagenkopf, E. C. Lund, T. Livinghouse, Tetrahedron 1995, 51, 4421-4438; M. I. Kemp, R. J. Whitby, S. J. Coote, Synthesis 1998, 557-568. Olefinic sulfur compounds have not been investigated in a similar reaction. For a recent application of sulfur-functionalized enynes in the cobalt-mediated Pauson-Khand reaction, see: J. Adrio, J. C. Carretero, J. Am. Chem. Soc. 1999, 121, 7411-7412; J. Adrio, M. R. Rivero, J. C. Carretero, Chem. Eur J. 2001, 7, 2435-2448; J. C. Carretero, J. Adrio, Synthesis 2001, 1888-1896.
17. For precedents, zirconacycles generated from acetylenic sulfides are known, but, in these cases, no unique behavior of the functionalized metallacycles has been observed. B. C. Van Wagenen, T. Livinghouse, Tetrahedron Lett. 1989, 30, 3495-3498; B. L. Pagenkopf, E. C. Lund, T. Livinghouse, Tetrahedron 1995, 51, 4421-4438; M. I. Kemp, R. J. Whitby, S. J. Coote, Synthesis 1998, 557-568. Olefinic sulfur compounds have not been investigated in a similar reaction. For a recent application of sulfur-functionalized enynes in the cobalt-mediated Pauson-Khand reaction, see: J. Adrio, J. C. Carretero, J. Am. Chem. Soc. 1999, 121, 7411-7412; J. Adrio, M. R. Rivero, J. C. Carretero, Chem. Eur J. 2001, 7, 2435-2448; J. C. Carretero, J. Adrio, Synthesis 2001, 1888-1896.
18. For precedents, zirconacycles generated from acetylenic sulfides are known, but, in these cases, no unique behavior of the functionalized metallacycles has been observed. B. C. Van Wagenen, T. Livinghouse, Tetrahedron Lett. 1989, 30, 3495-3498; B. L. Pagenkopf, E. C. Lund, T. Livinghouse, Tetrahedron 1995, 51, 4421-4438; M. I. Kemp, R. J. Whitby, S. J. Coote, Synthesis 1998, 557-568. Olefinic sulfur compounds have not been investigated in a similar reaction. For a recent application of sulfur-functionalized enynes in the cobalt-mediated Pauson-Khand reaction, see: J. Adrio, J. C. Carretero, J. Am. Chem. Soc. 1999, 121, 7411-7412; J. Adrio, M. R. Rivero, J. C. Carretero, Chem. Eur J. 2001, 7, 2435-2448; J. C. Carretero, J. Adrio, Synthesis 2001, 1888-1896.
19. For precedents, zirconacycles generated from acetylenic sulfides are known, but, in these cases, no unique behavior of the functionalized metallacycles has been observed. B. C. Van Wagenen, T. Livinghouse, Tetrahedron Lett. 1989, 30, 3495-3498; B. L. Pagenkopf, E. C. Lund, T. Livinghouse, Tetrahedron 1995, 51, 4421-4438; M. I. Kemp, R. J. Whitby, S. J. Coote, Synthesis 1998, 557-568. Olefinic sulfur compounds have not been investigated in a similar reaction. For a recent application of sulfur-functionalized enynes in the cobalt-mediated Pauson-Khand reaction, see: J. Adrio, J. C. Carretero, J. Am. Chem. Soc. 1999, 121, 7411-7412; J. Adrio, M. R. Rivero, J. C. Carretero, Chem. Eur J. 2001, 7, 2435-2448; J. C. Carretero, J. Adrio, Synthesis 2001, 1888-1896.
20. 3-carbon-metal bond of a certain zirconacycle proceeded with retention of configuration, which is consistent with the stereochemistry of the mechanism in Eq. (1). M. Mori, N. Uesaka, F. Saitoh, M. Shibasaki, J. Org. Chem. 1994, 59, 5643-5649.
21. For discussion on the configurational stability of α-metalated sulfides, see: R. W. Hoffmann, M. Julius, F. Chemla, T. Ruhland, G. Frenzen, Tetrahedron 1994, 50, 6049-6060; R. W. Hoffmann, R. K. Dress, T. Ruhland, A. Wenzel, Chem. Ber 1995, 128, 861-870; S. Nakamura, R. Nakagawa, Y. Watanabe, T. Toru, Angew. Chem. 2000, 112, 361-363; Angew. Chem. Int. Ed. 2000, 39, 353-355.
22. For discussion on the configurational stability of α-metalated sulfides, see: R. W. Hoffmann, M. Julius, F. Chemla, T. Ruhland, G. Frenzen, Tetrahedron 1994, 50, 6049-6060; R. W. Hoffmann, R. K. Dress, T. Ruhland, A. Wenzel, Chem. Ber 1995, 128, 861-870; S. Nakamura, R. Nakagawa, Y. Watanabe, T. Toru, Angew. Chem. 2000, 112, 361-363; Angew. Chem. Int. Ed. 2000, 39, 353-355.
23. For discussion on the configurational stability of α-metalated sulfides, see: R. W. Hoffmann, M. Julius, F. Chemla, T. Ruhland, G. Frenzen, Tetrahedron 1994, 50, 6049-6060; R. W. Hoffmann, R. K. Dress, T. Ruhland, A. Wenzel, Chem. Ber 1995, 128, 861-870; S. Nakamura, R. Nakagawa, Y. Watanabe, T. Toru, Angew. Chem. 2000, 112, 361-363; Angew. Chem. Int. Ed. 2000, 39, 353-355.
24. For discussion on the configurational stability of α-metalated sulfides, see: R. W. Hoffmann, M. Julius, F. Chemla, T. Ruhland, G. Frenzen, Tetrahedron 1994, 50, 6049-6060; R. W. Hoffmann, R. K. Dress, T. Ruhland, A. Wenzel, Chem. Ber 1995, 128, 861-870; S. Nakamura, R. Nakagawa, Y. Watanabe, T. Toru, Angew. Chem. 2000, 112, 361-363; Angew. Chem. Int. Ed. 2000, 39, 353-355.
25. 3-carbon atom, alkyl (refs. [6] and [7a-d]), allylic (ref. [7e]), benzylic (refs. [7b] and [7f]), and α-sulfenyl (this work) carbon atoms satisfied the above objective, but α-sulfonyl (this work) and α-alkoxycarbonyl (ref. [7d]) carbon atoms do not. For synthetic applications of the aforementioned stereodefined metallacycles, also see the following: a) S. F. Fillery, G. J. Gordon, T. Luker, R. J. Whitby, Pure Appl. Chem. 1997, 69, 633-638; (b) Z. Zhao, Y. Ding, G. Zhao, J. Org. Chem. 1998, 63, 9285-9291; (c) G. J. Gordon, T. Luker, M. W. Tuckett, R. J. Whitby, Tetrahedron 2000, 56, 2113-2129; (d) H. Urabe, K. Suzuki, F. Sato, J. Am. Chem. Soc. 1997, 119, 10014-10027; (e) H. Urabe, T. Takeda, D. Hideura, F. Sato, J. Am. Chem. Soc. 1997, 119, 11295-11305; (f) E. Negishi, D. Choueiry, T. B. Nguyen, D. R. Swanson, J. Am. Chem. Soc. 1994, 116, 9751-9752; See also: g) F. A. Hicks, N. M. Kablaoui, S. L. Buchwald, J. Am. Chem. Soc. 1996, 118, 9450-9451.
26. 3-carbon atom, alkyl (refs. [6] and [7a-d]), allylic (ref. [7e]), benzylic (refs. [7b] and [7f]), and α-sulfenyl (this work) carbon atoms satisfied the above objective, but α-sulfonyl (this work) and α-alkoxycarbonyl (ref. [7d]) carbon atoms do not. For synthetic applications of the aforementioned stereodefined metallacycles, also see the following: a) S. F. Fillery, G. J. Gordon, T. Luker, R. J. Whitby, Pure Appl. Chem. 1997, 69, 633-638; (b) Z. Zhao, Y. Ding, G. Zhao, J. Org. Chem. 1998, 63, 9285-9291; (c) G. J. Gordon, T. Luker, M. W. Tuckett, R. J. Whitby, Tetrahedron 2000, 56, 2113-2129; (d) H. Urabe, K. Suzuki, F. Sato, J. Am. Chem. Soc. 1997, 119, 10014-10027; (e) H. Urabe, T. Takeda, D. Hideura, F. Sato, J. Am. Chem. Soc. 1997, 119, 11295-11305; (f) E. Negishi, D. Choueiry, T. B. Nguyen, D. R. Swanson, J. Am. Chem. Soc. 1994, 116, 9751-9752; See also: g) F. A. Hicks, N. M. Kablaoui, S. L. Buchwald, J. Am. Chem. Soc. 1996, 118, 9450-9451.
27. 3-carbon atom, alkyl (refs. [6] and [7a-d]), allylic (ref. [7e]), benzylic (refs. [7b] and [7f]), and α-sulfenyl (this work) carbon atoms satisfied the above objective, but α-sulfonyl (this work) and α-alkoxycarbonyl (ref. [7d]) carbon atoms do not. For synthetic applications of the aforementioned stereodefined metallacycles, also see the following: a) S. F. Fillery, G. J. Gordon, T. Luker, R. J. Whitby, Pure Appl. Chem. 1997, 69, 633-638; (b) Z. Zhao, Y. Ding, G. Zhao, J. Org. Chem. 1998, 63, 9285-9291; (c) G. J. Gordon, T. Luker, M. W. Tuckett, R. J. Whitby, Tetrahedron 2000, 56, 2113-2129; (d) H. Urabe, K. Suzuki, F. Sato, J. Am. Chem. Soc. 1997, 119, 10014-10027; (e) H. Urabe, T. Takeda, D. Hideura, F. Sato, J. Am. Chem. Soc. 1997, 119, 11295-11305; (f) E. Negishi, D. Choueiry, T. B. Nguyen, D. R. Swanson, J. Am. Chem. Soc. 1994, 116, 9751-9752; See also: g) F. A. Hicks, N. M. Kablaoui, S. L. Buchwald, J. Am. Chem. Soc. 1996, 118, 9450-9451.
28. 3-carbon atom, alkyl (refs. [6] and [7a-d]), allylic (ref. [7e]), benzylic (refs. [7b] and [7f]), and α-sulfenyl (this work) carbon atoms satisfied the above objective, but α-sulfonyl (this work) and α-alkoxycarbonyl (ref. [7d]) carbon atoms do not. For synthetic applications of the aforementioned stereodefined metallacycles, also see the following: a) S. F. Fillery, G. J. Gordon, T. Luker, R. J. Whitby, Pure Appl. Chem. 1997, 69, 633-638; (b) Z. Zhao, Y. Ding, G. Zhao, J. Org. Chem. 1998, 63, 9285-9291; (c) G. J. Gordon, T. Luker, M. W. Tuckett, R. J. Whitby, Tetrahedron 2000, 56, 2113-2129; (d) H. Urabe, K. Suzuki, F. Sato, J. Am. Chem. Soc. 1997, 119, 10014-10027; (e) H. Urabe, T. Takeda, D. Hideura, F. Sato, J. Am. Chem. Soc. 1997, 119, 11295-11305; (f) E. Negishi, D. Choueiry, T. B. Nguyen, D. R. Swanson, J. Am. Chem. Soc. 1994, 116, 9751-9752; See also: g) F. A. Hicks, N. M. Kablaoui, S. L. Buchwald, J. Am. Chem. Soc. 1996, 118, 9450-9451.
29. 3-carbon atom, alkyl (refs. [6] and [7a-d]), allylic (ref. [7e]), benzylic (refs. [7b] and [7f]), and α-sulfenyl (this work) carbon atoms satisfied the above objective, but α-sulfonyl (this work) and α-alkoxycarbonyl (ref. [7d]) carbon atoms do not. For synthetic applications of the aforementioned stereodefined metallacycles, also see the following: a) S. F. Fillery, G. J. Gordon, T. Luker, R. J. Whitby, Pure Appl. Chem. 1997, 69, 633-638; (b) Z. Zhao, Y. Ding, G. Zhao, J. Org. Chem. 1998, 63, 9285-9291; (c) G. J. Gordon, T. Luker, M. W. Tuckett, R. J. Whitby, Tetrahedron 2000, 56, 2113-2129; (d) H. Urabe, K. Suzuki, F. Sato, J. Am. Chem. Soc. 1997, 119, 10014-10027; (e) H. Urabe, T. Takeda, D. Hideura, F. Sato, J. Am. Chem. Soc. 1997, 119, 11295-11305; (f) E. Negishi, D. Choueiry, T. B. Nguyen, D. R. Swanson, J. Am. Chem. Soc. 1994, 116, 9751-9752; See also: g) F. A. Hicks, N. M. Kablaoui, S. L. Buchwald, J. Am. Chem. Soc. 1996, 118, 9450-9451.
30. 3-carbon atom, alkyl (refs. [6] and [7a-d]), allylic (ref. [7e]), benzylic (refs. [7b] and [7f]), and α-sulfenyl (this work) carbon atoms satisfied the above objective, but α-sulfonyl (this work) and α-alkoxycarbonyl (ref. [7d]) carbon atoms do not. For synthetic applications of the aforementioned stereodefined metallacycles, also see the following: a) S. F. Fillery, G. J. Gordon, T. Luker, R. J. Whitby, Pure Appl. Chem. 1997, 69, 633-638; (b) Z. Zhao, Y. Ding, G. Zhao, J. Org. Chem. 1998, 63, 9285-9291; (c) G. J. Gordon, T. Luker, M. W. Tuckett, R. J. Whitby, Tetrahedron 2000, 56, 2113-2129; (d) H. Urabe, K. Suzuki, F. Sato, J. Am. Chem. Soc. 1997, 119, 10014-10027; (e) H. Urabe, T. Takeda, D. Hideura, F. Sato, J. Am. Chem. Soc. 1997, 119, 11295-11305; (f) E. Negishi, D. Choueiry, T. B. Nguyen, D. R. Swanson, J. Am. Chem. Soc. 1994, 116, 9751-9752; See also: g) F. A. Hicks, N. M. Kablaoui, S. L. Buchwald, J. Am. Chem. Soc. 1996, 118, 9450-9451.
31. 3-carbon atom, alkyl (refs. [6] and [7a-d]), allylic (ref. [7e]), benzylic (refs. [7b] and [7f]), and α-sulfenyl (this work) carbon atoms satisfied the above objective, but α-sulfonyl (this work) and α-alkoxycarbonyl (ref. [7d]) carbon atoms do not. For synthetic applications of the aforementioned stereodefined metallacycles, also see the following: a) S. F. Fillery, G. J. Gordon, T. Luker, R. J. Whitby, Pure Appl. Chem. 1997, 69, 633-638; (b) Z. Zhao, Y. Ding, G. Zhao, J. Org. Chem. 1998, 63, 9285-9291; (c) G. J. Gordon, T. Luker, M. W. Tuckett, R. J. Whitby, Tetrahedron 2000, 56, 2113-2129; (d) H. Urabe, K. Suzuki, F. Sato, J. Am. Chem. Soc. 1997, 119, 10014-10027; (e) H. Urabe, T. Takeda, D. Hideura, F. Sato, J. Am. Chem. Soc. 1997, 119, 11295-11305; (f) E. Negishi, D. Choueiry, T. B. Nguyen, D. R. Swanson, J. Am. Chem. Soc. 1994, 116, 9751-9752; See also: g) F. A. Hicks, N. M. Kablaoui, S. L. Buchwald, J. Am. Chem. Soc. 1996, 118, 9450-9451.
32. For reviews on the Pummerer reaction, see: A. Padwa, D. E. Gunn, Jr., M. H. Osterhout, Synthesis 1997, 1353-1377; O. De Lucchi, U. Miotti, G. Modena in Organic Reactions, Vol. 40 (Ed.: L. A. Paquette), Wiley, New York, 1991, pp. 157-406; D. S. Grierson, H.-P. Husson in Comprehensive Organic Synthesis. Vol. 6 (Eds.: B. M. Trost. I. Fleming), Pergamon, Oxford, 1991. pp. 909-947.
33. For reviews on the Pummerer reaction, see: A. Padwa, D. E. Gunn, Jr., M. H. Osterhout, Synthesis 1997, 1353-1377; O. De Lucchi, U. Miotti, G. Modena in Organic Reactions, Vol. 40 (Ed.: L. A. Paquette), Wiley, New York, 1991, pp. 157-406; D. S. Grierson, H.-P. Husson in Comprehensive Organic Synthesis. Vol. 6 (Eds.: B. M. Trost. I. Fleming), Pergamon, Oxford, 1991. pp. 909-947.
34. For reviews on the Pummerer reaction, see: A. Padwa, D. E. Gunn, Jr., M. H. Osterhout, Synthesis 1997, 1353-1377; O. De Lucchi, U. Miotti, G. Modena in Organic Reactions, Vol. 40 (Ed.: L. A. Paquette), Wiley, New York, 1991, pp. 157-406; D. S. Grierson, H.-P. Husson in Comprehensive Organic Synthesis. Vol. 6 (Eds.: B. M. Trost. I. Fleming), Pergamon, Oxford, 1991. pp. 909-947.
35. H. Urabe, T. Hamada, F. Sato, J. Am. Chem. Soc. 1999, 121, 2931-2932.
36. H. Urabe, F. Sato in Lewis Acids in Organic Synthesis, Vol. 2 (Ed.: H. Yamamoto), Wiley-VCH, Weinheim, 2000, pp. 653-798.
37. For reviews on chiral sulfoxides in organic synthesis, see: M. R. Barbachyn, C. R. Johnson in Asymmetric Synthesis, Vol. 4 (Ed.: J. D. Morrison, J. W. Scott), Academic Press, Orlando. 1984. pp. 227-261; A. J. Walker, Tetrahedron: Asymmetry 1992, 3, 961-998; C. C. Carreño, Chem. Rev. 1995, 95, 1717-1760; J. L. García Ruano, B. Cid de la Plata. Top. Curr Chem. 1999, 204, 1-126.
38. For reviews on chiral sulfoxides in organic synthesis, see: M. R. Barbachyn, C. R. Johnson in Asymmetric Synthesis, Vol. 4 (Ed.: J. D. Morrison, J. W. Scott), Academic Press, Orlando. 1984. pp. 227-261; A. J. Walker, Tetrahedron: Asymmetry 1992, 3, 961-998; C. C. Carreño, Chem. Rev. 1995, 95, 1717-1760; J. L. García Ruano, B. Cid de la Plata. Top. Curr Chem. 1999, 204, 1-126.
39. For reviews on chiral sulfoxides in organic synthesis, see: M. R. Barbachyn, C. R. Johnson in Asymmetric Synthesis, Vol. 4 (Ed.: J. D. Morrison, J. W. Scott), Academic Press, Orlando. 1984. pp. 227-261; A. J. Walker, Tetrahedron: Asymmetry 1992, 3, 961-998; C. C. Carreño, Chem. Rev. 1995, 95, 1717-1760; J. L. García Ruano, B. Cid de la Plata. Top. Curr Chem. 1999, 204, 1-126.
40. For reviews on chiral sulfoxides in organic synthesis, see: M. R. Barbachyn, C. R. Johnson in Asymmetric Synthesis, Vol. 4 (Ed.: J. D. Morrison, J. W. Scott), Academic Press, Orlando. 1984. pp. 227-261; A. J. Walker, Tetrahedron: Asymmetry 1992, 3, 961-998; C. C. Carreño, Chem. Rev. 1995, 95, 1717-1760; J. L. García Ruano, B. Cid de la Plata. Top. Curr Chem. 1999, 204, 1-126.
41. The starting vinyl sulfoxides were prepared from a commercially available sample of homochiral methyl tolyl sulfoxide and assumed to retain the same level of ee values (see reference [11]), Thus, the enantiomeric ratios shown in Eq. (3) and Table 2 have not been corrected for the actual ee values of the vinyl sulfoxides.