1. High Pressure Organic Chemistry. Part 21. For Part 20, see: Kotsuki, H.; Teraguchi, M.; Shimomoto, N.; Ochi, M. Tetrahedron Lett. 1996, 37, 3727–3730.
2. Bergman, E.D.; Ginsburg, D.; Pappo, R. Org. React. 1959, 10, 595–623. Perlmutter, P. Conjugate Addition Reactions in Organic Synthesis, Pergamon Press: Oxford, 1992.
3. Kobayashi, S. Synlett 1994, 689–701; Kobayashi, S. Yuki Gosei Kagaku Kyokai-shi 1995, 53, 370–380.
4. Keller, E.; Feringa, B.L. Tetrahedron Lett. 1996, 37, 1879–1882. We thank Dr. Keller for informing us the details of their reactions. See also: Keller, E.; Feringa, B.L. Synlett 1997, 842–844; Sasai, H.; Arai, T.; Shibasaki, M. J. Am. Chem. Soc. 1994, 116, 1571–1572.
5. Kotsuki, H.; Hayashida, K.; Shimanouchi, T.; Nishizawa, H. J. Org. Chem. 1996, 61, 984–990; Kotsuki, H.; Shimanouchi, T. Tetrahedron Lett. 1996, 37, 1845–1848.