Highly diastereoselective synthesis of 2,6-di[1-(2-akylaziridin-1-yl)alkyl]pyridines, useful ligands in palladium-catalyzed asymmetric allylic alkylation

C2-symmetric enantiopure 2,6-di[1-(1-aziridinyl)alkyl]pyridines (DIAZAP’s) were prepared by a high yielding three step sequence starting from 2,6-pyridinedicarbaldehyde and (S)-valinol or (S)-phenylglycinol. The new compounds were tested as ligands in palladium-catalyzed allylation of carbanions in different solvents. Almost quantitative yield and up to 99% enantiomeric excess were obtained in the reactions of the enolates derived from malonate, phenyl- and benzylmalonate dimethyl esters with 1,3-diphenyl-2-propenyl ethyl carbonate.