Houk previously pointed out that the most electron-withdrawing r-bond prefers to occupy the position eclipsed to the C@C
double bond.4 The orbital energy of rC@C is lower than that of rCAHA/gem. This is supported by the values of the diagonal elements of the Fock matrix in the bond orbital basis Fii (1.0903 a.u. for rC-C and 0.8241 a.u. for rCAHA/gem). Thus, rCAHA/gem is more electron-donating, which results in greater stabilization by the