1,2-DIMETHYLENECYCLOHEXANE: CYCLOHEXANE, 1,2-DIMETHYLENE

Note, as discussed in Reference 8, 1,3-dimethylenecyclohexane is some 10 kJ mol 1 more stable than its 1,4-isomer. The 1,3- and 1,4-dimethylene compounds are stabilized relative to the monomethylene compound by 19 and 9 kJmol-1, respectively, while the corresponding diketones are stabilized relative to the monoketone by some 7 and 4 kJmol-1. These results are consonant with the 1,3-bis-sp2 cyclohexanes being more stabilized than their 1,4-counterpart, but electrostatic destabilization affecting the /J-di ketone and not particularly the bismethylene compound. 

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