<span style="color:black;mso-bidi-language:HI">Theoretical study of facial selectivity and regioselectivity in electrophilic addition <span style="color:black;mso-bidi-language:HI">reaction of chlorine to <i><span style="mso-bidi-font-family:Arial;color:black;mso-bidi-language:HI">exo-</span></i><span style="mso-bidi-font-family:Arial;color:black;mso-bidi-language:HI">tricyclo[<span style="color:black;mso-bidi-language:HI">4.2.1.0^2,5]nona-3,7-diene </span></span></span></span>

Abstract

<span style="color:black;mso-bidi-language:HI">For prediction and interpretation of facial selectivity and regioselectivity of the electrophilic addition reaction to <i><span style="mso-bidi-font-family:Arial;color:black;mso-bidi-language: HI">exo</span></i><span style="color:black;mso-bidi-language:HI">tricyclo[4.2.1.0^{<span style="mso-bidi-font-family:Arial;color:black;mso-bidi-language:HI">2</span>}^{<span style="mso-bidi-font-family:Arial;color:#131313;mso-bidi-language:HI">,</span>}^{<span style="mso-bidi-font-family:Arial;color:black;mso-bidi-language:HI">5</span>}<span style="color:black;mso-bidi-language:HI">]nona-3,7-diene(exoTND) of chlorine<span style="color:#131313;mso-bidi-language:HI">, <span style="color:black; mso-bidi-language:HI">various models(geometric distortions<span style="color:#131313;mso-bidi-language:HI">, <span style="color:black; mso-bidi-language:HI">electron density, orbital effects, electrostatic effects and intermediates stabilities) have been used. Full geometric optimization of <i><span style="color:#131313;mso-bidi-language:HI">e</span></i><i><span style="color:black;mso-bidi-language:HI">xo</span></i><span style="color:black; mso-bidi-language:HI">TND<i> </i>molecule has been done by <i>ab initio </i>and DFT methods and the structure of the molecule have also been investigated. Norbornene double bond(II) of molecule is <i>endo </i>pyramidalized and cyclobuten double bond(II) is also <i>syn </i>pyramidalized<span style="color:#131313;mso-bidi-language:HI">. <span style="color:black; mso-bidi-language:HI">The double bond(I) is more pyramidalized than the double bond(III) and it has higher reactivity. <i>Exo </i>face of the double bond(I) and <i>anti </i>face of the double bond(II) of the molecule are regions having much more electron density(q<span style="color:#131313;mso-bidi-language: HI">i,_{<span style="color:black;mso-bidi-language:HI">HOMO</span>}<span style="color:black;mso-bidi-language:HI">) and bigger negative potential. The <i>exo</i>TND<i>-</i>Cl₂<i> </i>system has been investigated by B3LYP/6-311+G*<span style="mso-bidi-font-family:Arial;color:black;mso-bidi-language:HI"> <span style="color:black;mso-bidi-language:HI">method and their stable configurations have been determined. The <i><span style="color:#131313;mso-bidi-language: HI">e</span></i><i><span style="color:black;mso-bidi-language:HI">xo</span></i><span style="color:black;mso-bidi-language:HI">TND<i> ... </i>Cl₂) and <i>exo</i>TND<i> ... </i>Cl₂<i>(anti) </i>molecular complexes correspond to the most stable configurations of <i>exo</i>TND<i>-</i>Cl₂<i> </i>system<span style="color:#131313;mso-bidi-language:HI">. <span style="color:black; mso-bidi-language:HI">The most stable configuration of bridged cationic intermediates is the <i>exo-</i>bridged<i> </i>chloronium cation. The results that are obtained by using the models for predicted and interpredicted facial selectivity and

<span style="color:black;mso-bidi-language:HI">regioselectivity of the electrophilic addition reaction of chlorine to <i>exo</i>TND<i> </i>molecule agree with each other. Facial selectivity and regioselectivity of the addition reaction parallel the pyramidalization of the double bond.

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