Diastereoselectivity in intramolecular ene cyclisation A theoretical study

Diastereoselectivity in unactivated and activated ene cyclisation can be predicted using HF/6-31G(d) optimized geometry of the transition states. Relative energies of different conformations of the transition states, calculated using DFT, can be used for the prediction of product ratios. It was found that the dihedral angle around the forming carbon–carbon bond controls the cis–trans diastereoselectivity. A set of three model pericyclic transition structures has been proposed that mimics the activation process of ene cyclisation.Key words: intramolecular ene reaction, ab initio, DFT.