. The lowest barrierfor the stereochemical transition state (2.9 kcal/mol) was obtained for the2,4-dinitrophenoladditive (see Fig. and Table below). The highest barrier(10.4 kcal/mol) was obtained when 2,4,6-trinitrophenol was employed as the additive(see Fig. and Table below). The barriers for all the four cases matches the trend of the experimentally observed enantioselectivity. We note here that, in order to reduce the computational expense, we have focused on the favoured enantioselective pathway.