Synthesis of chiral diaza-18-crown-6 derivatives from optically active diethanolamines
作者:Erik F. J. de Vries、Pablo Steenwinkel、Johannes Brussee、Chris G. Kruse、Arne van der Gen
DOI:10.1021/jo00068a029
日期:1993.7
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.
Enantioselective oxidation of aromatic ketones by molecular oxygen, catalyzed by chiral monoaza-crown ethers
作者:Erik F.J. de Vries、Lisette Ploeg、Marcello Colao、Johannes Brussee、Arne van der Gen
DOI:10.1016/0957-4166(95)00138-f
日期:1995.5
Chiral monoaza-15-crown-5 ethers 3a-c and monoaza-18-crown-6 ethers 3d-f have been synthesized from optically active diethanolamines in moderate to good yields. One of these crown ethers, i.e. 3a, proved to be both an efficient and a selective phase transfer catalyst in the asymmetric oxidation of aromatic ketones:by molecular oxygen. Yields of the oxidation reaction were high and enantiomeric ! excesses of up to 72% could be obtained. To account for the remarkable differences in asymmetric induction between the crown ethers tested, a model for the:structure of the transition stare was proposed.
Schmidt, Archiv der Pharmazie, 1915, vol. 253, p. 57
作者:Schmidt
DOI:——
日期:——
Schmidt; Eberhard, Archiv der Pharmazie, 1915, vol. 253, p. 64,66