Mirror image conversions of cyclic conjugated non-planar allenes, C9H7X (X=H, F, Cl, Br)

Ab initio studies show the possibility of involvement of cyclic, planar, singlet and/or triplet 2-X-2,4,6,8-cyclononatetraenylidenes, carbenic transition states (1X-S* and/or 1X-T*), in the conversion of cyclic conjugated non-planar allenes, 1-X-1,2,4,6,8-cyclonona-pentaenes (1X), to their corresponding mirror images, 1X′ (where X=H, F, Cl and Br).