Storyboard: Part 1 The reactant is solvated by one molecule of THF. Solvent displaced by (SS) lactide monomer. Ring-opened lactide: . Geometry to second lactide mediated by a weak O...C=O electrostatic interaction (3.01Å). TS1: O...C=O bond formation mediated by strengthened O...C=O electrostatic interaction (2.88Å) and Stereoelectronic antiperiplanar orientation of the incoming O...C bond and the C-Me bond The original alkyl-oxygen coordination to Mg is preserved in TS1 which has a normal mode Enable Java 1.4.2_5 or later of 101i cm-1. The original alkyl-oxygen coordination to Mg is also preserved in the tetrahedral intermediate product from TS1.