Mehdi Bayat - Faculty of Chemistry, B u-Ali-Sina University, Hamedan, Iran
Fereshteh Yaghoobi - Faculty of Chemistry, B u-Ali-Sina University, Hamedan, Iran
Samaneh Hokmi, - Faculty of Chemistry, B u-Ali-Sina University, Hamedan, Iran
Sadegh Salehzadeh - Faculty of Chemistry, B u-Ali-Sina University, Hamedan, Iran

Since its discovery in ۱۹۲۸ [۱] by otto D iels and kurt Alder, the Diels-Alder (D-A) reaction has become one of the mos t powerful tools in organic synthesis. The Diels-Alder(DA) reacti on is perha ps the most widely used synthetic methodology for construction of a six- membered ring. I n this work, we report a theoretical study on the Diels–Alder (DA) reactions of ۱-methyl-۳-(m ethoxycarbonyl)-۲-nitroindolizine with R-۱, ۳-butadiene(RCHCHCH CH۲) (R=F, Cl, CH۳, S iH۳)[۲]. Fo r this reaction, we considered two possible different path ways (Fig ۱) in the pres ence and a bsence of methylaluminium dichloride as a catalyst. The relative energies and activ ation barriers of all model DA reactions in the gas phase and in methylene chloride were com puted.

Theoretical study , Diels-Alder, Activation barriers