1. For reviews, see: (a) Szantay, C.; Honty, K. In Monoterpenoid Indole Alkaloids; Saxton, J. E., Ed.; John Wiley: Chichester, 1994; chapter 4.
2. (b) Szantay, C.; Blasko, G.; Honty, K.; Dörnyei, G. In The Alkaloids; Brossi, A., Ed.; Academic Press: Chicago, 1986; Vol. 27, chapter 2, and references cited therein.
3. Nagakura, N.; Rüffer, M.; Zenk, M. H. J. Chem. Soc., Perkin Trans. 1 1979, 2308–2312.
4. (a) Brown, R. T. In Monoterpenoid Indole Alkaloids; Saxton, J. E., Ed.; John Wiley: New York, 1983; pp. 135–139, 192–194.
5. (b) Brown, R. T.; Dauda, B. E. N.; Santos, C. A. M. Chem. Commun. 1991, 825–826.