1. Zervas, L., Borovas, D., and Gazis, E., J. Amer. Chem. Soc., 85, 3660 (1963).
2. Zervas, L., Photaki, I., Poduska, K., and Sheppard, B. C., Proc. Seventh European Peptide Symp., Budapest, 1964, Acta Chim. Acad. Sci. Hung. (in the press).
3. For reviews compare Pettit, G. R., and Van Tamelen, E. E., in Org. Reactions, 12, 356 (1962). Hauptmann, H., and Walther, W. F., Chem. Rev., 62, 347 (1962).
4. McKay, F. C., and Albertson, N. F., J. Amer. Chem. Soc., 79, 4686 (1957); Anderson, G. W., and McGregor, A. C., 79, 6180 (1957).
5. Roeske, R., Chem. and Indust., 1121 (1959). Anderson, G. W., and Callahan, F. M., J. Amer. Chem. Soc., 82, 3359 (1960).