Contribution to the Theoretical Study of Reaction Mechanisms

An experimental and theoretical study of the hetero Diels–Alder reactions between (E)-2-aryl-1-cyano-1-nitroethenes and ethyl vinyl ether: one-step or zwitterionic, two-step mechanism?

“…2 reaction should be determined by a nucleophilic attack from the terminal, one position of ethyl vinyl ether 2 (N C1 = 2.27 eV) to the b-position of nitroalkene (x b = 1.29-1.58 eV [10] ). Such attack favors reaction channels XÀY is the distance between the reaction centers X and Y at the transition structure and r P XÀY is the same distance at the corresponding product [22] b Charge transfer t was calculated according to the expression given by Leroy et al [31] leading to nitronates three and four, which-as confirmed experimentally [11]actually formed during the reaction analyzed.…”

Approach to regiochemistry using local softness in 1,3-dipolar cycloadditions

“…Similar observations can also be made for other types of dipolarophiles. 22 We thus take 1,3-dipole as a nucleophile and dipolarophile as an electrophile for the 1,3-cycloaddition reactions. Hence, the ap-Ž .…”

Curly arrows meet electron density transfers in chemical reaction mechanisms: from electron localization function (ELF) analysis to valence-shell electron-pair repulsion (VSEPR) inspired interpretation

“…The former methods rely by construction on the choice of the expansion technique used to calculate the approximate wave function whereas the topological approach is, in its principles, free of arbitrariness. The localized orbital centroid evolution technique of Leroy et al, 41 the intrinsic bond orbitals transformations 42 and the valence bond approaches used by Karadakov 43 and by Harcourt 44 belong to the former group. The molecular electrostatic potential (MESP) topography approach of Balanarayan et al 45 is very attractive although the correspondences between the evolution of the MESP and the charge density transfers are stated rather than rigorously established.…”