Easy access to medium rings by entropy/strain reduction, part 4. A simple and mild route to some substituted 2,7-dihydro-1H-oxepins, thiepins and a phosphepin

Heterocycles

Volumn 53, Issue 4, 2000, Pages 897-904

  Walsh, James G ^a   Gilheany, Declan G ^a  

^a NATIONAL UNIVERSITY OF IRELAND   (Ireland)

Author keywords

[No Author keywords available]

Indexed keywords

OXEPINE DERIVATIVE; PHOSPHORUS DERIVATIVE; THIEPIN DERIVATIVE;

ARTICLE; CHEMICAL REACTION; CHEMICAL STRUCTURE; ENTROPY; REACTION ANALYSIS; REDUCTION; STEREOCHEMISTRY; SYNTHESIS;

EID: 0034177589     PISSN: 03855414     EISSN: None     Source Type: Journal    
DOI: 10.3987/com-99-8834     Document Type: Article

References (48)

1. Previous paper in this series: J.G. Walsh and D.G. Gilheany, J. Heterocyct. Chem., 1999, 36, submitted for publication.
2. Current address: Department of Chemistry, University College, Belfield, Dublin 4, Ireland. declan.gilheany@ucd.ie
3. G. Molander, Acc. Chem. Res., 1998, 31, 603; P. Deslongchamps, Aldrichimica Acta, 1984, 17, 59; G. Illuminati and L. Mandolini, Acc. Chem. Res., 1981, 14, 95 and references cited therein.
4. G. Molander, Acc. Chem. Res., 1998, 31, 603; P. Deslongchamps, Aldrichimica Acta, 1984, 17, 59; G. Illuminati and L. Mandolini, Acc. Chem. Res., 1981, 14, 95 and references cited therein.
5. G. Molander, Acc. Chem. Res., 1998, 31, 603; P. Deslongchamps, Aldrichimica Acta, 1984, 17, 59; G. Illuminati and L. Mandolini, Acc. Chem. Res., 1981, 14, 95 and references cited therein.
6. Preliminary communication: J. G. Walsh, P. F. Furlong, and D. G. Gilheany, J. Chem. Soc., Chem. Commun., 1994, 67.
7. J. G. Walsh, P. J. Furlong and D. G. Gilheany, J. Chem. Soc., Perkin Trans. 1, 1999, 3657.
8. We use the cis,cis terminology to mean the general stereochemistry that places the carboalkoxy, hydroxymethyl or bromomethyl group on the same side of the double bond as the other alkene moiety in each case. Individual compounds are of course named according to the E/Z nomenclature.
9. J. G. Walsh, P. F. Furlong, L. A. Byrne, and D. G. Gilheany, Tetrahedron, 1999, 55, 11519.
10. For overviews of heterocyclic medium rings see: A. R. Katritzky and C.W. Rees (eds.), 'Comprehensive Heterocyclic Chemistry', Pergamon Press, Oxford, 1984, Volumes 1 and 5; A. R. Katritzky, C. W. Rees and E. F. V. Scriven (eds.), 'Comprehensive Heterocyclic Chemistry II', Elsevier, Oxford, 1996, Volume 9, ed. by G. R. Newkome.
11. For overviews of heterocyclic medium rings see: A. R. Katritzky and C.W. Rees (eds.), 'Comprehensive Heterocyclic Chemistry', Pergamon Press, Oxford, 1984, Volumes 1 and 5; A. R. Katritzky, C. W. Rees and E. F. V. Scriven (eds.), 'Comprehensive Heterocyclic Chemistry II', Elsevier, Oxford, 1996, Volume 9, ed. by G. R. Newkome.
12. 4 16 substituted monocyclic dihydrothiepins are recorded in Beilstein (4/8/99) as either the sufide, sulfoxide or sulfone; (a) unsubstituted, dimethyl, trimethyl and acetoxymethyl: W. L. Mock, J. Amer. Chem. Soc., 1967, 89, 1282; W. L. Mock, J. Amer. Chem. Soc., 1969, 91, 5682; L. A. Paquette and S. Maiorana, J. Chem. Soc., Chem. Commun., 1971, 313; W. L. Mock and J. H. McCausland, J. Org. Chem., 1976, 41, 242;
13. 4 16 substituted monocyclic dihydrothiepins are recorded in Beilstein (4/8/99) as either the sufide, sulfoxide or sulfone; (a) unsubstituted, dimethyl, trimethyl and acetoxymethyl: W. L. Mock, J. Amer. Chem. Soc., 1967, 89, 1282; W. L. Mock, J. Amer. Chem. Soc., 1969, 91, 5682; L. A. Paquette and S. Maiorana, J. Chem. Soc., Chem. Commun., 1971, 313; W. L. Mock and J. H. McCausland, J. Org. Chem., 1976, 41, 242;
14. 4 16 substituted monocyclic dihydrothiepins are recorded in Beilstein (4/8/99) as either the sufide, sulfoxide or sulfone; (a) unsubstituted, dimethyl, trimethyl and acetoxymethyl: W. L. Mock, J. Amer. Chem. Soc., 1967, 89, 1282; W. L. Mock, J. Amer. Chem. Soc., 1969, 91, 5682; L. A. Paquette and S. Maiorana, J. Chem. Soc., Chem. Commun., 1971, 313; W. L. Mock and J. H. McCausland, J. Org. Chem., 1976, 41, 242;
15. 4 16 substituted monocyclic dihydrothiepins are recorded in Beilstein (4/8/99) as either the sufide, sulfoxide or sulfone; (a) unsubstituted, dimethyl, trimethyl and acetoxymethyl: W. L. Mock, J. Amer. Chem. Soc., 1967, 89, 1282; W. L. Mock, J. Amer. Chem. Soc., 1969, 91, 5682; L. A. Paquette and S. Maiorana, J. Chem. Soc., Chem. Commun., 1971, 313; W. L. Mock and J. H. McCausland, J. Org. Chem., 1976, 41, 242;
16. (b) phenyl and diphenyl: R. M. Dodson and J. P. Nelson, J. Chem. Soc., Chem. Commun., 1969, 1159; J. Nakayama, M. Tanuma, Y. Honda, and M. Hoshino, Tetrahedron Lett., 1984, 25, 4553; I. U. Khand and P. L. Pauson; Heterocycles, 1978, 11, 59;
17. (b) phenyl and diphenyl: R. M. Dodson and J. P. Nelson, J. Chem. Soc., Chem. Commun., 1969, 1159; J. Nakayama, M. Tanuma, Y. Honda, and M. Hoshino, Tetrahedron Lett., 1984, 25, 4553; I. U. Khand and P. L. Pauson; Heterocycles, 1978, 11, 59;
18. (b) phenyl and diphenyl: R. M. Dodson and J. P. Nelson, J. Chem. Soc., Chem. Commun., 1969, 1159; J. Nakayama, M. Tanuma, Y. Honda, and M. Hoshino, Tetrahedron Lett., 1984, 25, 4553; I. U. Khand and P. L. Pauson; Heterocycles, 1978, 11, 59;
19. (c) various dicarbomethoxy: D. N. Reinhoudt and C. G. Kouwenhoven, Recl. Trav. Chim. Pays-Bas, 1973, 92, 865; A. G. Schultz and T. H Fedynyshyn, Tetrahedron, 1982, 38, 1761;
20. (c) various dicarbomethoxy: D. N. Reinhoudt and C. G. Kouwenhoven, Recl. Trav. Chim. Pays-Bas, 1973, 92, 865; A. G. Schultz and T. H Fedynyshyn, Tetrahedron, 1982, 38, 1761;
21. (d) 3,4,5,6-tetrachloro: K. G. Orral, W. Carruthers, and M. G. Pellatt, Spectrochim. Acta A, 1972, 28, 753;
22. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
23. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
24. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
25. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
26. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
27. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
28. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
29. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
30. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
31. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
32. 4 and two other substitution patterns: 3-pyrrolidinyl-4,5-dicarbomethoxy: K. C. Brannock, R. D. Burpitt, V. W. Goodlett, and J. G. Thweatt, J. Org. Chem., 1963, 28, 1464; 2,7-dicarboxaldehyde: E. Alvarez, M. T. Diaz, R. Perez, J. L. Ravelo, A. Regueiro, J. A. Vera, D. Zurita, and J. D. Martin, J. Org. Chem., 1994, 59, 2848, the other known monocyclic 2,7-dihydrooxepins are either 2-oxo derivatives which are simply unsaturated lactones (8 cases): N. Hoshi and H. Uda, J. Chem. Res. M., 1985, 0925-0945 and references cited therein; R. J. Sundberg and B. C. Pearce, J. Org. Chem., 1982, 47; 725; or 2,7-dioxo derivatives which are merely muconic anhydrides (8 cases): G. J. Fonken, Chem. Ind. (London), 1961, 1575; P. Brassard and P. Karrer, Helv. Chim. Acta, 1960, 43, 262; M. M. Rogic and T. R. Demmin, J. Org. Chem., 1980, 45; 1153; G. Speier and Z. Tyeklar, J. Chem. Soc., Perkin Trans. 2, 1981, 1176; J. W. Jaroszewski and M. G. Ettlinger, J. Org. Chem., 1982, 47, 1212; H. Brodbeck, D. Bourgin, and R. Neier, Tetrahedron Lett., 1986, 27, 343; M. Speck, M. O. Senge, A. Schaefer, and H. Kurreck, Bioorg. Med. Chem. Lett., 1997, 7, 2589;
33. Phosphepins: 1-phenyl-1-oxo: G. Markl and H. Schubert, Tetrahedron Lett., 1970; 1273; 2,7-bis(tert-butyl): G. Markl and W. Burger, Angew. Chem., Int. Ed. Engl., 1984, 23, 894; five 4,5-dichloro-1-oxo cases: G. Keglevich, A. Szollosy, L. Toke, V. Fulop, and A. Kalman, J. Org. Chem., 1990, 55, 6361.
34. Phosphepins: 1-phenyl-1-oxo: G. Markl and H. Schubert, Tetrahedron Lett., 1970; 1273; 2,7-bis(tert-butyl): G. Markl and W. Burger, Angew. Chem., Int. Ed. Engl., 1984, 23, 894; five 4,5-dichloro-1-oxo cases: G. Keglevich, A. Szollosy, L. Toke, V. Fulop, and A. Kalman, J. Org. Chem., 1990, 55, 6361.
35. Phosphepins: 1-phenyl-1-oxo: G. Markl and H. Schubert, Tetrahedron Lett., 1970; 1273; 2,7-bis(tert-butyl): G. Markl and W. Burger, Angew. Chem., Int. Ed. Engl., 1984, 23, 894; five 4,5-dichloro-1-oxo cases: G. Keglevich, A. Szollosy, L. Toke, V. Fulop, and A. Kalman, J. Org. Chem., 1990, 55, 6361.
36. 2,7-dihydrophosphepins: 1-phenyl-, its 1-oxide and 4,5-dicarbomethoxy-1-phenyl-1-oxo: G. Markl and H. Schubert, Tetrahedron Lett., 1970; 1273; G. Markl and G. Dannhardt, Tetrahedron Lett., 1973, 1455; 4-chloro-3-methyl-l-phenyl and its oxide: G. Keglevich, H. T. T. Thanh, K. Ludanyi, T. Novak, K. Ujszaszy, and L. Toke, J. Chem. Res. S., 1998, 210; 1-chloro-2,2,4,6-tetraphenyl: G. Markl, H. Beckh, M. L. Ziegler, and B. Nuber, Angew. Chem., Int. Ed. Engl., 1987, 26, 1134; 3,5-bis(tert-butyl)-1-phenyl-1-oxo: reference 4.
37. 2,7-dihydrophosphepins: 1-phenyl-, its 1-oxide and 4,5-dicarbomethoxy-1-phenyl-1-oxo: G. Markl and H. Schubert, Tetrahedron Lett., 1970; 1273; G. Markl and G. Dannhardt, Tetrahedron Lett., 1973, 1455; 4-chloro-3-methyl-l-phenyl and its oxide: G. Keglevich, H. T. T. Thanh, K. Ludanyi, T. Novak, K. Ujszaszy, and L. Toke, J. Chem. Res. S., 1998, 210; 1-chloro-2,2,4,6-tetraphenyl: G. Markl, H. Beckh, M. L. Ziegler, and B. Nuber, Angew. Chem., Int. Ed. Engl., 1987, 26, 1134; 3,5-bis(tert-butyl)-1-phenyl-1-oxo: reference 4.
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