DFT study on the factors determining the enantioselectivity of Friedel-Crafts reactions of indole with N-acyl and N-tosylimines catalyzed by BINOL-phosphoric acid derivatives.

DFT methods have been used to study the mechanism and the enantioselectivity of the Friedel-Crafts reaction of indoles with acyl and tosyl imides catalyzed by BINOL-phosphoric acid catalysts. The results are in excellent agreement with the experimental enantioselectivities. The energies of the competing transition structures and, thus, the enantioselectivity are rationalized from calculations on a model system. We propose a simple model to predict the absolute configuration of the products.