exo conformation
1.For a-alkylcyclododecanone,the maximum barrier arrive at 53.9 KJ/mol, and the corresponding conformation is a-side-exo-[31233]-2-one.
2.For a-chlorine (or bromine) cyclo-dodecanones the maxima barriers are 43.9 KJ/mol and 44.3 KJ/mol respectively and the corresponding conformation is a-side-exo-[31233]-2-one.
