Molecular mechanism of Diels--Alder reaction between (E)-3,3,3-trichloro-1-nitropropene and cyclopentadiene: B3LYP/6-31G(d) computational study

Analysis of reactivity indexes supports the polar character of the reaction between (E)-3,3,3-trichloro-1-nitropropene and cyclopentadiene. This is confirmed by the analysis of electronic properties of transition complexes involved in the reaction paths using the B3LYP/6-31G(d) algorithm. The transition state s asymmetry is large, but it is insufficient to provoke a zwitterionic reaction mechanism. Attempts to find a heterocyclic intermediate 7 in the reaction path ultimately leading to 5-endo-nitro-6-exo-trichloromethylnorbornene 3 have been unsuccessful.