Unveiling the Chemo? and Regioselectivity of the [3+2] Cycloaddition Reaction between 4?Chlorobenzonitrile Oxide and ??Aminocinnamonitrile with a MEDT Perspective**

A molecular electron density theory (MEDT) study for the [3+2] cycloaddition (32CA) reaction of 4-chlorobenzonitrile oxide (CBNO) and ?-aminocinnamonitrile (ACN) has been performed at MPWB1K/6-311G(d,p) computational level. This 32CA reaction, characterised as zwitterionic type (zw-type), presents an activation enthalpy 11.8, 14.2 16.6 kcal mol?1, in gas phase, benzene methanol. The formation 3-aryl-5-(?-aminostyryl)-1,2,4-oxadiazole is predicted energetically feasible one following a non-concerted two-stage one-step mechanism. zw-type shows total chemo regioselectivity. global transfer most favourable transition state structure (TS), higher than 0.14 e, suggests some polar character. favoured TS intramolecular hydrogen bond between amine ?NH2 ACN oxygen CBNO, which favours this reaction. behaviour enhanced with inclusion methanol molecule bonded to atom. present MEDT that best experimental conditions are use non-polar solvent such containing catalytic amounts protic