Didehydrophenyl cation

A three-center interaction similar to that in m-pyridynes 100 and 102 (Scheme 16.26) results in substantial stabilization in the two-electron case. 3,5-Didehydrophenyl cation (111), the classic example for in-plane aromaticity, is the global minimum of the C6H3+ hypersurface.Remarkably, the... 

In contrast to benzynes and benzdiynes (cf. Section 6.2), knowledge of tridehy-droarenes is scarce. According to calculations by Bettinger et al. 1,2,4-tridehy-drobenzene (121) and 1,3,5-tridehydrobenzene (122) are less stable than the 1,2,3-isomer 123 by 4.0 and 11.8 kcal/mol, respectively. In contrast to didehydrophenyl cation 111 (Section 5), 122 possesses C2v symmetry the calculated Cl—C3 and Cl—C5 distances are different (194 and 230 pm, respectively, at the CCSD/DZP level of theory). For the 1,2,3-isomer 123 a significantly shorter Cl—C3-distance ( 170 pm) is predicted by various methods. 

---

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

---