Alder reaction of cyclopropene with furan

Diels-Alder Reaction of Cyclopropene with Furan 

Theory Model Exo Transition State Structure rfis/A r62/A ri6.4/A rey/A r43/A a 63/° 

The computed geometries for two isomeric transition states are presented in Table 5. All computational methods predicted a synchronous formation of the two new C-C bonds and a concerted mechanism for the cycloaddition reaction. Due to the lack of an electron correlation in the HF ab initio computational approach, the computed bonds were substantially shorter when compared with experimental data or computational data obtained with correlational computational methods. If the two isomeric transition state structures obtained with DFT (B3LYP and BLYP) methods are taken into consideration, then it can be seen that the exo transition state structure is the closest structure to the reactants. According to the Hammond postulate [38], the exo transition state structure should then have a lower energy than the isomeric endo transition state structure. 

Theory Model B06-3 BOe-2 BO15-2 BO16-2 HOMO LUMO 

BO = bond order BOe-3 is the bond order between carbon atoms 6 and 3 in the transition state structures. 

---