DFT Study of Pericyclic and Pseudopericyclic Thermal Cheletropic Decarbonylations. Evaluation of Magnetic Properties

Abstract

A comprehensive B3LYP/6-31G** study of various thermal cheletropic decarbonylations was conducted. The complete pathway for each reaction was determined, and changes in magnetic susceptibility and its anisotropy were monitored with a view to estimating the aromatization associated to each process. This information, together with the energy and structural results, allowed us to clarify cases that are not clearly pseudopericyclic or pericyclic from previous work. Also, our results reveal that pericyclic reactions involve no disconnection in the cyclic array of overlapping orbitals. Therefore, a pseudopericyclic reaction involves at least one such disconnection. In any case, pseudopericyclic reactions involving two disconnections exhibit much clearer features, which facilitates their classification.

Fluorine effect on pericyclic and pseudopericyclic processes: Evidences and ab initio theory

“…Later many methods based on the magnetic properties such as NICS, 7,8 ACID 9-12 have been developed to characterize pseudeopericyclic reactions. These methods were successfully used by Rodrίguez Otero and their coworkers, [13][14][15][16][17][18][19] to identify the nature of reactions as pericyclic or pseudopericyclic. Lopez and de Lera et al 20 showed that pseudopericyclic reactions do not show a maximum in ellipticity of the forming bond along the reaction coordinate.…”

Coarctate cyclization reactions: a primer

“…[32][33][34][35] Pseudopericyclic transition states exhibit a disconnection in their otherwise cyclic system of delocalized electrons. 36 In ACID plots this is nicely reflected by a disconnection in the ACID surface.…”

Face‐ and Regioselectivity in Electrophilic Phenylsulfenylation of 7‐tert‐Butoxybicyclo[2.2.1]hepta‐2,5‐dienes

“…During our continuous interest in the construction of large π systems , we developed the cheletropic cycloreversion expelling carbon monooxide in the fusion of π systems yielding very large π compounds as well as the retro‐Diels–Alder protocol . Among the pericyclic cycloreversion reactions, cheletropic degradation reactions extruding carbon mono‐oxide are the most advantageous, even if the target π systems are reactive and labile . We have successfully utilized the reactions for construction of acene derivatives such as naphthacenes , pentacenes , and an anthracene‐fused pyrrole .…”