Asymmetric introduction of heteroatoms

Selective introduction of heteroatom substituents represents one of the continuing challenges for new methodology. Asymmetric introduction of oxygen, nitrogen, and sulfur substituents via palladium catalyzed allylic alkylations becomes possible in three different ways-1) desymmetrization of meso-2-ene-1,4-diol diesters, 2) deracemization of allylic esters via meso eta(3)-allyl intermediates, and 3) deracemization of an unsymmetrical allyl system wherein racemization occurs via an eta(3)-eta(1)-eta(3)-isomerization mechanism. Applications of this methodology have resulted in numerous total syntheses including asymmetric syntheses of pancratistatin, carbanucleosides, nucleosides, amino acids, phyllanthocin, and vinylglycinol among others.