Understanding the molecular mechanism of the [3 + 2] cycloaddition reaction of benzonitrile oxide toward electron‐rich N‐vinylpyrrole: a DFT study. (23rd February 2016)

• Record Type: Journal Article
• Authors: Domingo, Luis R.; Emamian, Saeedreza; Salami, Majid; Ríos‐Gutiérrez, Mar
• Is Part Of: Journal of physical organic chemistry. Volume 29:Number 7(2016)
• Page Start: 368
• Page End: 376
• Publication Date: 2016-02-23
• Subjects: [3 + 2] cycloaddition reactions -- benzonitrile oxide -- DFT reactivity indices -- ELF topological analysis -- molecular mechanism -- regioselectivity; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.3544
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract : The[3 + 2] cycloaddition (32CA) reaction of benzonitrile oxide, BNO2, with an electron‐rich N ‐vinylpyrrole derivative, NVP3a, in the presence of dichloromethane, has been theoretically studied using density functional theory (DFT) methods at the B3LYP/6‐31G(d) level. This 32CA reaction presents a relatively high activation Gibbs free energy as a result of the low polar character of this zwitterionic‐type ( zw‐type ) reaction. Analyses of the calculated relative Gibbs free energies and transition state geometries indicate that the studied 32CA reaction, in excellent agreement with experimental outcomes, takes place in a completeregioselective manner as a consequence of the steric repulsions that appear at the most unfavorable transition state. An electron localization function (ELF) topological analysis of the bonding changes along this 32CA reaction supports a non‐concerted two‐stage one‐step molecular mechanism in which the formation of the O3‐ C5 single bond takes place at the end of the reaction after the complete formation of the C1‐C4 one. Copyright © 2016 John Wiley & Sons, Ltd. Abstract : The complete regioselective [3 + 2] cycloaddition reaction of BNO2 toward NVP3a in the presence of dichloromethane takes place via a non‐concerted two‐stage one‐step molecular mechanism confirmed by the electron localization function quantum topological analysis.