SYNTHESIS OF CHIRAL DIAZA-18-CROWN-6 DERIVATIVES FROM OPTICALLY-ACTIVE DIETHANOLAMINES

Homotopic 1,10-diaza-18-crown-6 derivatives with two, four, and six chiral centers have been prepared in optically active form from diethanolamines via a cyclization reaction with tosylates 39 and 48. The requisite optically active diethanolamines were prepared from chiral cyanohydrins and chiral ethanolamines by a one-pot Grignard-transimination-reduction or a one-pot reduction-transimination-reduction procedure. Yields were strongly affected by the size of the substituents alpha to the nitrogen atom. The stereoselectivity of the diethanolamine synthesis was found to depend on the configuration of the ethanolamine used.