... Soc., 82,66.5 (1960). (6) W. P. Jencks and J. Carriuolo, J. Am. Chem. SOC., 82, 675 (1960). (7) C. K. Ingold, Structure and Mechanism in Organic Chemistry, Cornell University Press, Ithaca, NY, 1953, p. 306 .ff ... Soc., 80,209 (1958). Hanson, J. Am. Chem. Sac.. 70, 819 (1948). ...