Synthesis of chiral diaza-18-crown-6 derivatives from optically active diethanolamines
摘要:
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.
A simple chiral derivatisation protocol for 1H NMR spectroscopic analysis of the enantiopurity of O-silyl-1,2-amino alcohols
作者:Magdalena E. Powell、Andrew M. Kelly、Steven D. Bull、Tony D. James
DOI:10.1016/j.tetlet.2008.12.013
日期:2009.2
A simplechiral derivatisation protocol for determining the enantiopurity of O-silyl-protected-1,2-amino alcohols by 1HNMRspectroscopicanalysis is described, which involves their treatment with 2-formylphenylboronic acid and enantiopure (syn)-methyl-2,3-dihydroxy-3-phenylpropionate to afford mixtures of imino-boronate esters whose diastereoisomeric ratio is an accurate reflection of the enantiopurity
描述了一种简单的手性衍生方案,可通过1 H NMR光谱分析确定O-甲硅烷基保护的1,2-氨基醇的对映体纯度,涉及用2-甲酰基苯基硼酸和对映纯(syn)-甲基-2处理3-二羟基-3-苯基丙酸酯提供亚氨基-硼酸酯的混合物,其非对映异构体比率准确反映了母体氨基醇的对映体纯度。