1. For reviews, see: (a) Bobitt, J. M.; Segebarth, K. P. Cyclopentanoid Terpene Derivatives; Marcel Dekker: New York, 1969;
2. (b) Bianco, A. In Studies in Natural Products Chemistry; Rhaman, A. U., Ed.; Elsevier: Amsterdam, 1990; Vol. 7, p. 439;
3. (c) Franzyk, H. In Progress in the Chemistry of Organic Natural Products; Herz, W.; Falk, H.; Kirby, G. W.; Moore, R. E., Eds.; Springer-Verlag: Wien, 2000; Vol. 73, pp. 1–114.
4. Synthesis of cyclopenta[C]pyran skeleton of iridoid lactones