Synthesis of an enantiopure scorpionate ligand by a nucleophilic addition to a ketenimine and a zinc initiator for the isoselective ROP of rac-lactide.

A novel nucleophilic addition of an organolithium to a ketenimine to prepare an enantiopure NNN-heteroscorpionate ligand is described. We verified its potential utility as a valuable scaffold for chirality induction through the preparation of enantiopure zinc complexes, which behave as highly efficient initiators to produce highly-enriched isotactic poly(lactide)s (Pi up to 0.88).