Long-range through-bond photoactivated σ bond cleavage in steroids. Intramolecular sensitized debromination

Organic Letters

Volumn 2, Issue 1, 2000, Pages 15-18

  Li, Wen Shan ^a   Morrison, Harry ^a  

^a PURDUE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000554529     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol990319s     Document Type: Article

References (46)

1. Organic Photochemistry. 118. For part 117, see: Timberlake, L. D.; Morrison, H. J. Am. Chem. Soc. 1999, 121, 3618.
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5. (d) Agyin, J. K.; Morrison, H.; Siemiarczuk, A. J. Am. Chem. Soc. 1995, 117, 3875.
6. (e) Jiang, S. A.; Xiao, C.; Morrison, H. J. Org. Chem. 1996, 61, 7045.
7. (f) Agyin, J. K.; Timberlake, L. D.; Morrison, H. J. Am. Chem. Soc. 1997, 119, 7945.
8. Liang, N.; Miller, J. R.; Closs, G. L. J. Am. Chem. Soc. 1990, 112, 5353.
9. Tong, Z.-H.; Yang, G.-Q.; Wu, S.-K. Chinese J. Chem. 1990, 61.
10. Cao, H.; Akinoto, Y.; Fujiwara, Y.; Tanimoto, Y.; Zhang, L.-P.; Tung, C.-H. Bull. Chem. Soc. Jpn. 1995, 68, 3411. Tung, C.-H.; Zhang, L.-P.; Yi, L. Chinese. J. Chem. 1996, 14, 377. Tung, C.-H.; Zhang, L.-P.; Yi, L.; Cao, H.; Tanimoto, Y. J. Phys. Chem. 1996, 100, 4480. Tung, C.-H.; Zhang, L.-P.; Yi, L.; Cao, H.; Tanimoto, Y. J. Am. Chem. Soc. 1997, 119, 5348.
11. Cao, H.; Akinoto, Y.; Fujiwara, Y.; Tanimoto, Y.; Zhang, L.-P.; Tung, C.-H. Bull. Chem. Soc. Jpn. 1995, 68, 3411. Tung, C.-H.; Zhang, L.-P.; Yi, L. Chinese. J. Chem. 1996, 14, 377. Tung, C.-H.; Zhang, L.-P.; Yi, L.; Cao, H.; Tanimoto, Y. J. Phys. Chem. 1996, 100, 4480. Tung, C.-H.; Zhang, L.-P.; Yi, L.; Cao, H.; Tanimoto, Y. J. Am. Chem. Soc. 1997, 119, 5348.
12. Cao, H.; Akinoto, Y.; Fujiwara, Y.; Tanimoto, Y.; Zhang, L.-P.; Tung, C.-H. Bull. Chem. Soc. Jpn. 1995, 68, 3411. Tung, C.-H.; Zhang, L.-P.; Yi, L. Chinese. J. Chem. 1996, 14, 377. Tung, C.-H.; Zhang, L.-P.; Yi, L.; Cao, H.; Tanimoto, Y. J. Phys. Chem. 1996, 100, 4480. Tung, C.-H.; Zhang, L.-P.; Yi, L.; Cao, H.; Tanimoto, Y. J. Am. Chem. Soc. 1997, 119, 5348.
13. Cao, H.; Akinoto, Y.; Fujiwara, Y.; Tanimoto, Y.; Zhang, L.-P.; Tung, C.-H. Bull. Chem. Soc. Jpn. 1995, 68, 3411. Tung, C.-H.; Zhang, L.-P.; Yi, L. Chinese. J. Chem. 1996, 14, 377. Tung, C.-H.; Zhang, L.-P.; Yi, L.; Cao, H.; Tanimoto, Y. J. Phys. Chem. 1996, 100, 4480. Tung, C.-H.; Zhang, L.-P.; Yi, L.; Cao, H.; Tanimoto, Y. J. Am. Chem. Soc. 1997, 119, 5348.
14. Zhu, Y.; Schuster, G. B. J. Am. Chem. Soc. 1993, 115, 2190.
15. Pearl, D. M.; Burrow, P. D.; Nash, J. J.; Morrison, H.; Jordan, K. D. J. Am. Chem. Soc. 1993, 115, 9876. Nash, J. J.; Carlson, D. V.; Kaspar, A. M.; Love, D. E.; Jordan, K. D.; Morrison, H. J. Am. Chem. Soc. 1993, 115, 8969. Maxwell, B. D.; Nash, J. J.; Morrison, H. A.; Falcetta, M. L.; Jordan, K. D. J. Am. Chem. Soc. 1989, 111, 7914.
16. Pearl, D. M.; Burrow, P. D.; Nash, J. J.; Morrison, H.; Jordan, K. D. J. Am. Chem. Soc. 1993, 115, 9876. Nash, J. J.; Carlson, D. V.; Kaspar, A. M.; Love, D. E.; Jordan, K. D.; Morrison, H. J. Am. Chem. Soc. 1993, 115, 8969. Maxwell, B. D.; Nash, J. J.; Morrison, H. A.; Falcetta, M. L.; Jordan, K. D. J. Am. Chem. Soc. 1989, 111, 7914.
17. Pearl, D. M.; Burrow, P. D.; Nash, J. J.; Morrison, H.; Jordan, K. D. J. Am. Chem. Soc. 1993, 115, 9876. Nash, J. J.; Carlson, D. V.; Kaspar, A. M.; Love, D. E.; Jordan, K. D.; Morrison, H. J. Am. Chem. Soc. 1993, 115, 8969. Maxwell, B. D.; Nash, J. J.; Morrison, H. A.; Falcetta, M. L.; Jordan, K. D. J. Am. Chem. Soc. 1989, 111, 7914.
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21. Seapy, D. G.; Gonzales, J.; Cameron, K. O. J. Photochem. Photobiol., A 1992, 64, 35.
22. For an interesting recent study of intramolecular electron transfer induced electrochemically in 1-methyl-4-benzyloxycyclohexyl bromide, see: Antonello, S.; Maran, F. J. Am. Chem. Soc. 1998, 120, 5713.
23. Lodder, G.; Cornelisse, J. Recent Advances in the Photochemistry of the Carbon-Halogen Bond; Wiley and Sons, 1995.
24. Cristol, S. J.; Micheli, R. P. J. Am. Chem. Soc. 1978, 100, 850 and references therein.
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27. Dannenberg, J. J.; Dill, K. Tetrahedron Lett. 1972, 1571.
28. Morrison, H.; Agyin, K.; Jiang, A.; Xiao, C. Pure Appl. Chem. 1995, 67, 111.
29. 19
30. Wu, Z.-Z.; Morrison, H. Tetrahedron Lett. 1990, 31, 5865.
31. 3 and silylation of the C3 α-alcohol by TPSCl. The configurations of the TPSO and bromine groups were assigned by NMR and confirmed by X-ray analysis of 3.
32. Satisfactory analytical and spectroscopic data have been obtained for all new compounds reported herein.
33. Using a Continuum NY-61 Nd:YAG laser equipped with a frequency quadrupler (30 mW, 10 Hz, ca. 3.0-3.3 mJ/pulse) and with a 2× beam enlarger in front of a 1 cm square Vycor cell.
34. Prepared from 3α-hydroxy-5α-androstan-17-one by Wolff-Kishner reduction of the ketone and silylation of the alcohol.
35. Nor was there debromination of the 3αOH/17αBr by 266 nm light when this compound was irradiated by itself, thus ensuring that the photochemistry of 2 is initiated by light absorption by the TPSO antenna.
36. Interestingly, the TPSO chemistry was unquenched by piperylene.
37. This is a minimum value since the extent of recombination of the initially created radical or ion pairs cannot be determined from the data in hand.
38. Prepared from testosterone via initial conversion to the 17β hydroxy, 3,6 dione, conversion of the alcohol to the 17α bromide, and selective reduction and silylation at C3.
39. -4 M) used in the emission experiments.
40. Prepared from dehydroisoandrosterone in four steps.
41. The structures are assigned on the basis of spectral analysis. Those for compounds 4, 5, and 8 were confirmed by comparison with independently prepared authentic samples.
42. This is clearly a product resulting from homolysis of the C-Br bond. There was no evidence for the C17 alcohol one might have anticipated had heterolysis been observed. For a recent, relevant discussion, see: Lipson, A.; Deniz, A. A.; Peters, K. S. Chem. Phys. Lett. 1998, 288, 781 and references therein.
43. Using a Luminics EX-700 Pulse Master Excimer Laser at 308 nm, 30 mW power (10 Hz, 3.5 mJ/pulse).
44. Using the singlet and triplet energies for a cyclohexanone as taken from Turro, N. J. Modern Molecular Photochemistry; Benjamin/Cummings: Menlo Park, CA, 1978; p 290.
45. Benson, S. W. Thermochemical Kinetics; Wiley: New York, 1968.
46. Studies to determine the rate constant and overall efficiency for triplet energy transfer from the C3 TPSO antenna to C17Br are in progress.