Reductive coupling of aromatic aldehydes promoted by an aqueous TiCl 3/tBuOOH system in alcoholic cosolvents

European Journal of Organic Chemistry

Volumn , Issue 24, 2007, Pages 4050-4055

  Clerici, Angelo ^a   Greco, Cosimina ^a   Panzeri, Walter ^b   Pastori, Nadia ^a   Punta, Carlo ^a   Porta, Ombretta ^a  

^a POLITECNICO DI MILANO   (Italy)

^b CNR   (Italy)

Author keywords

Aldehydes; Radical chemistry; Reductive dimerization; Substituent effects; Titanium

Indexed keywords

EID: 34548067737     PISSN: 1434193X     EISSN: 10990690     Source Type: Journal    
DOI: 10.1002/ejoc.200700252     Document Type: Article

References (36)

1. M. Finn, R. Friedline, N. K. Suleman, C. J. Whol, J. M. Tanko, J. Am. Chem. Soc. 2004, 126, 7578-7584 and references cited therein.
2. V. Malatesta, J. C. Scaiano, J. Org. Chem. 1982, 47, 1455-1459.
3. a) H. Paul, R. D. Small, J. C. Scaiano, J. Am. Chem. Soc. 1978, 100, 4520-4524;
4. b) S. K. Wang, J. Am. Chem. Soc. 1979, 101, 1235-1239.
5. D. Griller, J. A. Howard, P. R. Marriot, J. C. Scaiano, J. Am. Chem. Soc. 1981, 103, 619-623.
6. M. Weber, H. Fischer, J. Am. Chem. Soc. 1999, 121, 7381-7388 and references cited therein.
7. H), see: J. C. Scaiano in Landolt-Börnstein: Numerical Data and Functioned Relationships in Science and Technology - New Series: Vol. II/13d: Radical Reactions Rates in Liquid (Ed.: H. Fischer), Springer, Berlin, Germany, 1984, pp. 12-26.
8. A. Clerici, R. Cannella, N. Pastori, W. Panzeri, O. Porta, Tetrahedron 2006, 62, 5986-5994.
9. a) For a recent review on pinacol coupling reaction, see: A. Chatteerjee, N. N. Joshi, Tetrahedron 2006, 62, 12137-12158;
10. b) A. Clerici, N. Pastori, O. Porta, Eur. J. Org. Chem. 2002, 3326-3335;
11. c) A. Clerici, O. Porta, J. Org. Chem. 1985, 50, 76-81:
12. d) A. Clerici, O. Porta, Tetrahedron Lett. 1982, 23, 3517-3520;
13. e) A. Clerici, L. Clerici, O. Porta, Tetrahedron Lett. 1996, 37, 3035-3038.
14. a) V. Jagannadahn, S. Steenken, J. Am. Chem. Soc. 1988, 110, 2188-2192;
15. b) V. Jagannadahn, S. Steenken, J. Am. Chem. Soc. 1984, 106, 6542-6551;
16. c) M. Mc Millan, R. O. C. Norman, J. Chem. Soc. B 1968, 590-597;
17. d) W. E. Griffiths, G. F. Longer, J. Myatt, P. F. Todd, J. Chem. Soc. B 1966, 1130-1132;
18. e) W. T. Dixon, R. O. C. Norman, J. Chem. Soc. B 1963, 3119-3124.
19. [6]: vol. II/13b, pp. 311-339.
20. -1, respectively.
21. For a review, see: B. R. Roberts, Chem. Soc. Rev. 1999, 28, 25-25.
22. 2C(OH) radicals are -0.94 and -1.06 V, respectively; a) J. Lilie, G. Beck, A. Henglein, Ber. Bunsen-Ges. Phys. Chem. 1971, 75, 458;
23. b) Z. B. Alfassi (Ed.), General Aspects of the Chemistry of Radicals, Wiley Interscience, 1999, p. 420.
24. [3a]). However, oxidation of A' by peroxide may well be a competitive reaction (see: E. S. Huyser, C. J. Bredeweg, J. Am. Chem. Soc. 1964, 86, 2401-2405).
25. B. G. Gilbert, P. D. R. Marshall, R. O. C. Norman, N. Pined, P. S. Williams, J. Chem. Soc. Perkin Trans. 2 1981, 1392-1400.
26. [10], pp 7-8).
27. J. March, Advanced Organic Chemistry, 3rd ed., Wiley Interscience, 1985, p. 244.
28. ESR coupling constants show that para substitution stabilizes, whereas meta substitution destabilizes benzyl radical. J. M. Dust, D. R. Arnold, J. Am. Chem. Soc. 1983, 105, 1221-1227.
29. 3 is negative, indicating that a methoxy group destabilizes a benzyl radical. Delocalization of the odd electron on the oxygen atom of the methoxyl is only possible by a charge separated structure like Bg′. However, when the donor atom is not a first row element, but a higher period element like Br, derealization of the odd electron becomes possible by expansion of the octet due to low-lying d orbitals. T. H. Fisher, A. W. Meierhoefer, J. Org. Chem. 1978, 43, 224-228 and references cited therein.
30. a) H. G. Viehe, Z. Janousek, R. Mereny, L. Stella, Acc. Chem. Res. 1985, 18, 148-154;
31. b) I. MacInnes, J. C. Walton, J. Chem. Soc. Perkin Trans. 2 1987, 1077-1082;
32. c) F. M. Welle, H. D. Beckhaus, C. Rüchardt, J. Org. Chem. 1997, 62, 552-558;
33. d) J. J. Brocks, H. D. Beckhaus, A. L. J. Beckwith, C. Rüchardt, J. Org. Chem. 1998, 63, 1935-1943.
34. The relevant references for known diols 2 are given in sequence: a) 2a and 2g: A. Furstner, R. Csuk, C. Rohrer, H. Weidmann, J. Chem. Soc. Perkin Trans. 1 1988, 1729-1734;
35. b) 2e, 2f, and 2d: L. Wang, Y. Zhang, Tetrahedron 1988, 54, 11129-11140;
36. [8]