CHIRAL IMIDAZOLIDIN-2-ONES IN ASYMMETRIC-SYNTHESIS

Chiral auxiliaries and ligands form the basis of much of the modern de velopment of asymmetric synthesis. The recent literature has burgeoned with contributions in these two highly topical areas. This review loo ks critically at the, as yet, rather unheralded role that chiral imida zolidin-2-ones have, and continue, to play in this fertile research fi eld. In certain respects, imidazolidin-2-ones represent a refinement o f a number of earlier successful auxiliaries/ligands. In addition, the y contribute some unique features to the methodology of asymmetric syn thesis because of their generally higher crystallinity, resistance of the. heterocycle to nucleophilic ring-opening, and their N-bifunctiona lity which permits their construction in C-2-symmetric form.