... (7) Cristol, SJ; Bindel, TH J. Am. Chem. SOC. 1981,103,7287-7293. (8) By analogy with the unsubstituted system? ... A molecular orbital corre- @.- p. +: (9) Nonhebel, D. C.; Walton, J. C. “Free-radical Chemistry”; The University Press: Cambridge, 1974; p 513. ...