A DFT study of [3+2] cycloaddition reactions of an azomethine imine with N-vinyl pyrrole and N-vinyl tetrahydroindole

作者：Rios Gutierrez Mar^*; Chafaa Fouad; Nacereddine Abdelmalek Khorief^*; Djerourou Abdelhafid; Domingo Luis R

来源：Journal of Molecular Graphics and Modelling, 2016, 70: 296-304.

DOI：10.1016/j.jmgm.2016.10.009

• Azomethine imines
• Vinyl pyrroles
• [3+2] Cycloadditions
• Molecular mechanism
• Selectivity
• DFT calculations

The mechanism and selectivities of the [3+2] cycloaddition (32CA) reactions of azomethine imine (Al) 8 with two N-vinyl five-membered heterocycles (NVFH), 9a and 9b, have been theoretically studied using DFT methods at the MPWB1K/6-31G(d) computational level. The possible ortho/meta regio- and endo/exo stereoselective channels were explored and characterised. The low polar character of these 32CA reactions, which is the consequence of the high nucleophilic character of both reagents, as well as the non-effective reactivity of these NVFH as nucleophiles, accounts for the high calculated activation energies, 16.1 (9a) and 16.8 (9b) kcal mol(-1) in chlorobenzene. Analysis of the relative electronic and free energies associated with the different reaction pathways indicates that the 32CA reactions of the AI with these NVFH are highly meta regioselective but present a poor stereoselectivity, in agreement with the experimental observations. Finally, electron localisation ELF) topological analysis allows characterising the mechanism of these 32CA reactions as a non-concerted two-stage one-step mechanism.

• 出版日期2016-11