DESYMMETRIZATION OF PROCHIRAL DIESTERS VIA TRANSITION-METAL-CATALYZEDREACTIONS

The development of asymmetric induction in palladium catalyzed allylic alkylation has led to the notion of creating a chiral pocket. Two pla tforms for ligand design that may generate such ''chiral space'' evolv e from derivatizing chiral diols or diamines with 2-diphenylphosphinob enzoic acid or chiral diacids with 2-diphenylphosphinoaniline. Palladi um complexes derived from such ligands effect excellent enantiodiscrim ination in the desymmetrization of esters of meso-cycloalk-2-en-1,4-di ols and gem dicarboxylates of alpha,beta-unsaturated aldehydes. These methods prove useful for asymmetric syntheses of carbanucleosides, nuc leosides, and the antitumor alkaloid (+)-pancratistatin.