Highly efficient trapping of short-lived 1,4-diradicals, the order of first bond formation in the intramolecular photocycloaddition of 3-(4'-pentenyl)-cyclohex-2-enones

Tetrahedron Letters

Volumn 37, Issue 49, 1996, Pages 8941-8944

  Becker, Dan ^a   Galili, Nitsa ^a   Haddad, Nizar ^a  

^a TECHNION ISRAEL INSTITUTE OF TECHNOLOGY   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

POLYCYCLIC HYDROCARBON;

ARTICLE; CYCLIZATION; DRUG SYNTHESIS; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; PHOTOCHEMISTRY; REACTION ANALYSIS; STEREOCHEMISTRY; X RAY ANALYSIS;

EID: 0030566794     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(96)02053-9     Document Type: Article

References (26)

1. 1. (a) Becker, D.; Nagler, M.; Hirsh, S.; Ramun, J. J. Chem. Soc., Chem. Commun., 1983, 371;
2. (b) Becker, D.; Haddad, N. Isr. J. Chem. 1989, 29, 303.
3. (c) Becker, D.; Nagler, M.; Sahali, Y.; Haddad, N. J. Org. Chem. 1991, 56, 4537.
4. 2. (a) Hammond, G. S.; Liu, R. S. J. Am. Chem. Soc., 1967, 89, 4930;
5. (b) Carlough, K. H.; Srinivasan, R. J. Am. Chem. Soc., 1967, 89, 4932.
6. 3. (a) Becker, D.; Haddad, N.; Sahali, Y. Tetrahedron Lett., 1989, 30, 2661;
7. (b) Becker, D.; Morlender, N.; Haddad, N. Tetrahedron Lett. 1995, 36, 1921.
8. 4. (a) Newcomb, M.; Glenn, A. G. J. Am. Chem. Soc., 1989, 111, 275;
9. (b) Bowry, V. W.; Lusztyk, J.; Ingold, K. U. J. Am. Chem. Soc., 1991, 113, 5687;
10. 5. (a) Newcomb, M.; Glenn, A. G.; Williams, W. G. J. Org. Chem., 1989, 54, 2675;
11. (b) Newcomb, M.; Johnson, C. C; Manek, M. B.; Varick, T. R. J. Am. Chem. Soc., 1992, 114, 10915;
12. (c) Bowry, V. W.; Lusztyk, J.; Ingold, K. U. J. Am. Chem. Soc., 1991, 113, 5687.
13. 2Se as the trapping reagent: Maradyn, D. J.; Weedon, A. J. Am. Chem. Soc., 1955, 117, 5359.
14. 7. Chiral cyclopropyl 10 was prepared in an optically pure form, needed for further mechanistic studies, following Hacksell's procedure: Vallgarda, J.; Hacksell, U. Tetrahedron Lett., 1991, 32, 5625; Vallgarda, J.; Appelberg, U.; Csoregh, I.; Hacksell, U. J. Chem. Soc. Perkin Trans. I, 1994, 461.
15. 7. Chiral cyclopropyl 10 was prepared in an optically pure form, needed for further mechanistic studies, following Hacksell's procedure: Vallgarda, J.; Hacksell, U. Tetrahedron Lett., 1991, 32, 5625; Vallgarda, J.; Appelberg, U.; Csoregh, I.; Hacksell, U. J. Chem. Soc. Perkin Trans. I, 1994, 461.
16. 8. (a) Wittig, G.; Schoellkopt, U. Org. Syn. Coll. Vol. V, 1973, 751;
17. (b) Corey, E. J.; Suggs, W. Tetrahedron Lett., 1975, 16, 2647.
18. 9. Conia, J. M.; Rouessac, F. Bull. Soc. Chim. Fr. 1963, 1925.
19. 10. 80-W Hanau mercury vapor lamp (Q-81) was used for irradiations via a Uranium glass filter (λ> 330). All irradiations were carried out in 18 mL of hexane as solvent under nitrogen atmosphere. The concentrations always kept below 0.05 M and the reactions followed by TLC or GC.
20. 11. All new compounds were characterized by full spectroscopic data, yields refer to chromatographed materials with purity of >95%.
21. 12. The relative stereochemical relationship of the stereogenic centers was determined by NOE-difference. The location of these protons determined by combination of COSY-45, XH-CORR, JMOD-XH methods and was supported by NOE experiments. For determination of similar structures by NMR cf.: ref. (3b) and (a) Becker, D.; Haddad, N. Tetrahedron 1993, 49, 947. Becker, D.;
22. (b) Haddad, N. Isr. J. Chem. 1989, 29, 303.
23. -3, (a) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467;
24. 2=5.8 Hz, 1H), 3.21 (m, 1H), 2.45 (m, 1H), 2.41 (s, 1H), 2.21 (m, 1H), 2.15 (m, 4H), 1.86-1.56 (m, 8H).
25. 14. Calculated using the Macro model V-3.5X of Allinger MM2 program. The calculated conformations are in full agreement with the NOE results.
26. 15. "Cross" photoproducts usually formed as major products in the intramolecular photocycloadditions of cyclicenones possessing shorter alkenyl side chain, cf.: Wolff, S.; Agosta, W. C. J. Am. Chem. Soc., 1983, 105, 1292 and 1299.