1. Comprehensive Heterocyclic Chemistry; Katritzky, A., Rees, C. W., Scriven, E. F. V., Eds.; Elsevier Science: Oxford, UK, 1996.
2. Martin, S. F. In The Alkaloids; Brossi, A., Ed.; Academic: New York, 1987; Vol. 30, pp 251–377; Lewis, J. R. Nat. Prod. Rep. 1994, 11, 329; Jeffs, P. W. In The Alkaloids; Rodrigo, R. G. A., Ed.; Academic: New York, 1981; Vol. 19, pp 1–80.
3. Kuehne, M. E.; Matsko, T. H.; Bohnert, J. C.; Motyka, L.; Oliver-Smith, D. J. Org. Chem. 1981, 46, 2002; Kuehne, M. E.; Earley, W. G. Tetrahedron 1983, 39, 3707; Kuehne, M. E.; Brook, C. S.; Xu, F.; Parsons, R. Pure Appl. Chem. 1994, 66, 2095; Nkiliza, J.; Vercauteren, J. Tetrahedron Lett. 1991, 32, 1787; Rawal, V. H.; Michoud, C.; Monestel, R. F. J. Am. Chem. Soc. 1993, 46, 3030.
4. Overman, L. E.; Sworin, M.; Burk, R. M. J. Org. Chem. 1983, 48, 2685; Overman, L. E.; Sugai, S. Helv. Chim. Acta. 1985, 68, 745; Overman, L. E.; Robertson, G.; Robichaud, A. J. J. Org. Chem. 1989, 54, 1236.
5. Gallagher, T.; Magnus, P.; Huffman, J. C. J. Am. Chem. Soc. 1983, 105, 4750; Magnus, P.; Gallagher, T.; Brown, P.; Pappalardo, P. Acc. Chem. Res. 1984, 17, 35.