Dipolar Additions with 1-(6-Chloropyridazin-3-yl)pyridinium-3-olate and 1,1′-(Pyridazine-3,6-diyl)di(pyridinium-3-olate)

Abstract

The regio- and stereo-selectivities of the cycloadditions of the title pyridinium-3-olates at the 2- and 6-positions with mono- and di-substituted alkenes are elucidated and rationalised, including secondary orbital overlap and taking into account steric and dipolar effects: for electron-acceptor and conjugated alkenes, all add in the same regioselective sense, with the stereoselectivity being shown to depend on the structure of the pyridinium-3-olate and the addend.

References

1. M. K. Awad and N. M. Nahas, in press.
2. N. Dennis, A. R. Katritzky and Y. Takeuchi, Angew. Chem., Int. Ed. Engl., 1976, 15, 1 and references cited therein.
3. S. A. El-Abbady, H. A. Abdulhamid, A. A. Shalaby, M. G. Ahmed and A. H. Moustafa, Indian J. Chem., 1989, 28B, 923.
4. S. A. El-Abbady, H. A. Abdulhamid, A. A. Shalaby, M. G. Ahmed and A. H. Moustafa, J. Prakt. Chem., 1989, 331, 105.
5. M. L. Iskandar, S. A. El-Abbady, A. A. Shalaby and A. H. Moustafa, Collect. Czech. Chem. Commun., 1992, 57, 1951.
6. A. H. Moustafa, A. A. Shalaby and R. A. Jones, J. Chem. Res., 1983, (S) 37; (M) 0564.
7. S. A. El-Abbady and M. K. Awad, Pol. J. Chem., 1995, 69, 33.
8. S. A. El-Abbady and A. H. Moustafa, J. Chem. Res., 1995, (S) 298; (M) 1701.
9. S. A. El-Abbady and S. M. Agami, Indian J. Chem., 1995, 34B, 504.
10. S. A. El-Abbady, Indian J. Hetergocycl. Chem., 1993, 3, 25.
11. S. A. El-Abbady and S. M. Agami, Heterocycl. Comm., in press.
12. S. A. El-Abbady, A. H. El-Askalani and M. K. Awad, Egypt. J. Chem., in press.