The stereodifferentiating potential of arabinosyl aldimines was utilized in stereoselective syntheses of 2-substituted dehydropiperidinones and their further transformation to 2,6-cis-substituted piperidinones. The absolute configuration was proven by X-ray analysis and by the synthesis of the enantiomerically pure alkaloid (+)-dihydropinidine. The presented method offers the possibility to synthesize
阿拉伯糖醛亚胺的立体分化潜力可用于立体选择性合成 2-取代脱氢哌啶酮及其向 2,6-顺式取代哌啶酮的进一步转化。通过 X 射线分析和对映体纯生物碱 (+)-二氢吡啶的合成证明了绝对构型。所提出的方法提供了合成哌啶衍生物对映异构体的可能性,这些衍生物是通过应用相应的半乳糖胺辅助剂获得的。
Carbohydrates as Chiral Templates: Stereoselective Synthesis of (<i>R</i>)- and (<i>S</i>)-α-Aminophosphonic Acid Derivatives
作者:Sabine Laschat、Horst Kunz
DOI:10.1055/s-1992-34155
日期:——
The stereoselective synthesis of diethyl (S)- or (R)-α-[(O-pivaloyl-hexapyranosyl) amino]benzylphosphonates is achieved via Lewis acid catalyzed addition of diethyl phosphite to O-pivaloylated N-benzylidene -β-D-galactosylamine or N-benzylidene-α-D-arabinopyranosylamine. The process can also be performed by a one-pot procedure selectively giving (S)-aminophosphonic acid derivatives from galactosylamine and (R)-aminophosphonic acid derivatives from β-L-fucosylamine as the chiral auxiliaries.
Carbohydrates as chiral templates: Diastereoselective Ugi synthesis of (S)-amino acids using O-acylated D-arabinopyranosylamine as the auxiliary
作者:Horst Kunz、Waldemar Pfrengle、Wilfried Sager
DOI:10.1016/s0040-4039(00)99334-1
日期:1989.1
Enantiomerically pure (S)-amino acids are synthesized via a highly diastereoselective Ugi reaction using 2,3,4-tri-O-pivaloyl-α-D-arabinopyranosylamine as the chiraltemplate.
Stereoselective Total Synthesis of the Diastereomeric Tricyclic Alkaloids Tetraponerine-7 and Tetraponerine-8 Using O-Pivaloylated d-Arabinopyranosylamine as the Common Auxiliary
Based on a diastereoselective domino Mannich-Michael reaction cascade of 2-N-[(S)-3-(benzyloxycarbonyl)[4-(tert-butyldiphenylsiloxy)butyl]amino}octylidene]-2,3,4-tri-O-pivaloyl--d-arabinopyranosylamine with the Danishefsky diene, the major component of the neurotoxic venom of the New Guinean ant Tetraponera punctulata, tetraponerine-8, and its diastereomer tetraponerine-7 were synthesized in pure form. While the Mannich reaction of the arabinosyl imine of the required (S)-configured -aminoaldehyde gave the 2-substituted piperidinone precursor of tetraponerine-8 with excellent diastereoselectivity, the analogous Mannich reaction of the (R)-configured -aminoaldehyde afforded the precursor of tetraponerine-7 with a selectivity of only 2:1 (mismatched case). The enantiomerically pure tetraponerine-8, described as highly toxic for ants, exhibited only moderate toxicity to sucking and stinging insects.