Application of β-Phosphorylated Nitroethenes in [3+2] Cycloaddition Reactions Involving Benzonitrile N-Oxide in the Light of a DFT Computational Study

The regiochemistry of [3+2] cycloaddition (32CA) processes between benzonitrile N-oxide 1 and β-phosphorylated analogues nitroethenes 2a–c has been studied using the Density Functional Theory (DFT) at M062X/6-31+G(d) theory level. obtained results reactivity indices show that can be classified both as a moderate electrophile nucleophile, while strong electrophiles marginal nucleophiles. Moreover, analysis CDFT shows for cycloadditions with participation β-phosphorylatednitroethene 2a α-cyanonitroethene 2b, more favored reaction path forms 4-nitro-substituted Δ2-isoxazolines 3a–b, β-cyanonitroethene 2c, 5-nitro-substituted Δ2-isoxazoline 4c. This is due to presence cyano group in alkene. study correlates well kinetic description considered channels. DFT calculations have proven clearly polar nature all analyzed reactions according one-step mechanism.